US20120090782A1 - Microwave plasma source and plasma processing apparatus - Google Patents
Microwave plasma source and plasma processing apparatus Download PDFInfo
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- US20120090782A1 US20120090782A1 US13/276,642 US201113276642A US2012090782A1 US 20120090782 A1 US20120090782 A1 US 20120090782A1 US 201113276642 A US201113276642 A US 201113276642A US 2012090782 A1 US2012090782 A1 US 2012090782A1
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Classifications
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
- H01J37/32192—Microwave generated discharge
- H01J37/32293—Microwave generated discharge using particular waveforms, e.g. polarised waves
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/46—Generating plasma using applied electromagnetic fields, e.g. high frequency or microwave energy
- H05H1/461—Microwave discharges
- H05H1/463—Microwave discharges using antennas or applicators
Definitions
- the present disclosure relates to a microwave plasma source and a plasma processing apparatus using the same.
- a plasma processing apparatus such as a plasma etching apparatus or a plasma CVD apparatus has been used for performing a plasma process such as an etching process or a film forming process on a processing target substrate such as a semiconductor wafer or a glass substrate.
- RLSA Random Line Slot Antenna microwave plasma processing apparatus capable of uniformly generating high-density surface wave plasma having a low electron temperature is attracting attention (see, for example, Patent Document 1).
- the RLSA microwave plasma processing apparatus includes a planar antenna (radial line slot antenna) having slots formed in a certain pattern.
- the planar antenna is provided in an upper portion of a chamber (processing vessel). Microwave induced from a microwave generation source through a coaxial waveguide is radiated into the chamber from the slots of the planar antenna. A gas introduced into the chamber is excited into plasma by a microwave electric field. Accordingly, a plasma process is performed on a processing target object such as a semiconductor wafer.
- Patent Document 2 is a microwave plasma source that splits microwave into a multiple number of microwaves, radiates the split microwaves into a chamber through a multiple number of antenna modules and combines the split microwaves in a space within the chamber.
- the microwaves in the space within the chamber by using the multiple number of antenna modules, phases or intensity of the microwaves radiated from the antennas of the antenna modules can be adjusted. As a result, the plasma distribution can also be adjusted.
- Patent Document 1 Japanese Patent Laid-open Publication No. 2000-294550
- Patent Document 2 Pamphlet of International Patent Publication No. 2008/013112
- antinodes and nodes of a standing wave generated when the microwaves are radiated into the chamber can occur.
- the antinodes and the nodes of the standing wave may cause non-uniformity of an electron density distribution in the plasma. As a result, a plasma density distribution may not become uniformized.
- the present disclosure provides a microwave plasma source capable of controlling positions of nodes and antinodes of a standing wave of microwave within the processing chamber not to be fixed and improving uniformity of a plasma density distribution within the processing chamber. Further, the present disclosure also provides a plasma processing apparatus using the microwave plasma source.
- a microwave plasma source for introducing microwave into a processing chamber capable of performing a plasma process by exciting a gas supplied into the processing chamber into plasma by the microwave.
- the microwave plasma source includes a microwave generator for generating microwave; and a microwave supply unit configured to supply the generated microwave into the processing chamber.
- the microwave supply unit includes a multiple number of microwave introducing devices each introducing the microwave into the processing chamber; and a multiple number of phase controllers for adjusting phases of the microwaves input to the multiple number of microwave introducing devices.
- the phases of the microwaves may be adjusted by fixing an input phase of the microwave input to one of two adjacent microwave introducing devices while varying an input phase of the microwave input to the other microwave introducing device according to a periodic waveform.
- the phases of the microwaves may be adjusted by varying input phases of the microwaves input to both of the two adjacent microwave introducing devices according to periodic waveforms not overlapped with each other.
- the periodic waveform may be one of a sine waveform, a triangular waveform, a trapezoidal waveform and a waveform similar to a sine waveform.
- the microwave plasma source may further include a ceiling plate serving as a top wall of the processing chamber and configured to transmit the microwaves radiated from the multiple number of microwave introducing devices.
- the ceiling plate may include a multiple number of dielectric members provided at positions corresponding to the multiple number of microwave introducing devices; and a metal frame, having a honeycomb structure, for supporting the dielectric members.
- the frame may have a gas flow path and a multiple number of gas discharge holes. Further, a gas used for the plasma process may be discharged into the processing chamber from the gas discharge holes.
- a plasma processing apparatus including a processing chamber for accommodating therein a processing target substrate; a mounting table for mounting thereon the processing target substrate within the processing chamber; a gas supply unit for supplying a gas into the processing chamber; and the aforementioned microwave plasma source.
- plasma may be generated by microwave introduced into the processing chamber from the microwave plasma source. Further, a process may be performed on the processing target substrate by the plasma.
- the phases of the microwaves may be adjusted by fixing the input phase of the microwave inputted to one of two adjacent microwave introducing devices while varying the input phase of the microwave inputted to the other microwave introducing device according to the periodic waveform.
- the phases of the microwaves may be adjusted by varying input phases of the microwaves inputted to both of the two adjacent microwave introducing devices according to periodic waveforms not overlapped with each other. Accordingly, by continuously changing the positions of the nodes and the antinodes of the standing wave generated when the microwaves are radiated into the processing chamber, it may be possible to uniformize electric field intensity and to improve in-plane uniformity of the electric field intensity. As a result, an electron density, i.e., a plasma density within the processing chamber can be uniformized, and a uniform plasma process can be performed.
- FIG. 1 is a cross sectional view illustrating a schematic configuration of a surface wave plasma processing apparatus having a microwave plasma source in accordance with a first embodiment of the present disclosure
- FIG. 2 is a configuration view of the microwave plasma source
- FIG. 3 is a plane view schematically illustrating a microwave supply unit of the microwave plasma source
- FIG. 4 shows an example circuit configuration of a main amplifier of an antenna module of the microwave plasma source
- FIG. 5 is a cross sectional view illustrating a microwave introducing device of the antenna module of the microwave plasma source
- FIG. 6 is a transversal cross sectional view taken along a line AA′ of FIG. 5 , and shows a power supply unit of the microwave introducing device;
- FIG. 7 is a transversal cross sectional view taken along a line BB′ of FIG. 5 , and shows a slug and a sliding member of a tuner;
- FIG. 8 is a schematic diagram for describing a case where input phases of microwaves inputted to three microwave introducing devices among seven microwave introducing devices of the microwave plasma source are varied according to a periodic waveform;
- FIG. 9 shows an input phase with time when an input phase of microwave inputted to one of adjacent microwave introducing devices is fixed to 0° while varying an input phase of microwave inputted to the other microwave introducing device according to a sine waveform
- FIGS. 10A to 10C show example periodic waveforms other than a sine waveform
- FIGS. 11A and 11B respectively show analysis results of electric field distributions within a chamber in a case where input phases of microwaves inputted to all of the seven microwave introducing devices of the microwave plasma source shown in FIG. 3 are set to be about 0° and in a case where input phases of microwaves inputted to three outer microwave introducing devices are changed by about 180°;
- FIG. 12 is a plane view schematically illustrating a microwave supply unit and a ceiling plate of a microwave plasma source in accordance with a second embodiment of the present disclosure.
- FIG. 13 is a cross sectional view taken along a line CC′ of FIG. 12 ;
- FIG. 14 is a plane view schematically illustrating a modification example of the ceiling plate.
- FIG. 15 is a bottom view illustrating another modification example of the ceiling plate.
- FIG. 1 is a cross sectional view illustrating a schematic configuration of a surface wave plasma processing apparatus having a microwave plasma source in accordance with a first embodiment of the present disclosure.
- FIG. 2 is a configuration view of the microwave plasma source.
- FIG. 3 is a plane view schematically illustrating a microwave supply unit of the microwave plasma source.
- FIG. 4 shows an example circuit configuration of a main amplifier of an antenna module of the microwave plasma source.
- FIG. 5 is a cross sectional view illustrating a microwave introducing device of the antenna module of the microwave plasma source.
- FIG. 6 is a transversal cross sectional view taken along a line AA′ of FIG. 5 , and shows a power supply unit of the microwave introducing device.
- FIG. 7 is a transversal cross sectional view taken along a line BB′ of FIG. 5 , and shows a slug and a sliding member of a tuner.
- a surface wave plasma processing apparatus 100 is configured as a plasma etching apparatus that performs a plasma process such as an etching process on a wafer.
- the surface wave plasma processing apparatus 100 may include a substantially cylindrical chamber 1 and a microwave plasma source 2 for generating microwave plasma within the chamber 1 .
- the chamber 1 is made of a metal material such as aluminum or stainless steel, and is airtightly sealed. Further, the chamber 1 is electrically grounded.
- An opening 1 a may be formed at a top portion of the chamber 1 , and the microwave plasma source 2 is provided in the opening la so as to face the inside of the chamber 1 .
- a susceptor 11 for horizontally mounting thereon a wafer W as a processing target object is provided within the chamber 1 .
- the susceptor 11 is supported on a cylindrical supporting member 12 that is provided at a center of a bottom of the chamber 1 via an insulating member 12 a.
- the susceptor 11 and the supporting member 12 may be made of, e.g., aluminum having an alumite-treated (anodically oxidized) surface.
- the susceptor 11 may include an electrostatic chuck for electrostatically attracting the wafer W, a temperature control device, a gas flow path for supplying a heat transfer gas to a rear surface of the wafer W and a vertically movable elevating pin for transferring the wafer W. Further, the susceptor 11 is electrically connected with a high frequency bias power supply 14 via a matching unit 13 . A high frequency power is supplied to the susceptor 11 from the high frequency bias power supply 14 , so that ions in the plasma may be attracted toward the wafer W.
- a gas exhaust pipe 15 is connected to the bottom of the chamber 1 , and a gas exhaust unit 16 including a vacuum pump is connected with the gas exhaust pipe 15 .
- the chamber 1 is evacuated, so that the inside of the chamber 1 can be depressurized to a certain vacuum level at a high speed.
- a loading/unloading port 17 for loading and unloading the wafer W and a gate valve 18 for opening and closing the loading/unloading port 17 are provided at a sidewall of the chamber 1 .
- a shower plate 20 for discharging a processing gas for plasma etching toward the wafer W is horizontally provided above the susceptor 11 within the chamber 1 .
- the shower plate 20 includes a lattice-shaped gas flow path 21 and a multiple number of gas discharge holes 22 formed in the gas flow path 21 . There exist spaces 23 between lattice patterns of the gas flow path 21 .
- An outwardly extending pipe 24 is connected to the gas flow path 21 of the shower plate 20 .
- the pipe 24 is connected with a processing gas supply source 25 .
- a ring-shaped plasma gas introducing member is provided along the sidewall of the chamber 1 at a position above the shower plate 20 of the chamber 1 , and a multiple number of gas discharge holes are formed at an inner periphery of the plasma gas introducing member 26 .
- the plasma gas introducing member 26 is connected to a plasma gas supply source 27 for supplying the plasma gas via a pipe 28 .
- a rare gas such as an Ar gas may be used as the plasma gas.
- the plasma gas introduced into the chamber 1 from the plasma gas introducing member 26 is excited into plasma by the microwave introduced into the chamber 1 from the microwave plasma source 2 .
- This plasma travels in the spaces 23 of the shower plate 20 and excites the processing gas discharged from the gas discharge holes 22 of the shower plate 20 . As a result, plasma of the processing gas is generated.
- the microwave plasma source 2 is provided on a ceiling plate 110 supported by a supporting ring 29 placed at the upper portion of the chamber 1 .
- a gap between the supporting ring 29 and the ceiling plate 110 is hermetically sealed.
- the microwave plasma source 2 includes a microwave output unit 30 for splitting and outputting microwaves and a microwave supply unit 40 for guiding and radiating the microwaves outputted into the chamber 1 from the microwave output unit 30 .
- the microwave output unit 30 includes a microwave power supply 31 , a microwave oscillator 32 , an amplifier 33 and a splitter 34 .
- the amplifier 33 amplifies the oscillated microwave, and the splitter 34 splits the amplified microwave in plural numbers.
- the microwave oscillator 32 oscillates microwave of a certain frequency (e.g., about 2.45 GHz), by way of example, by PLL (Phase Locked Loop).
- the splitter 34 splits the microwave amplified by the amplifier 33 while matching input impedance with output impedance so as to reduce a loss of the microwave.
- the microwave may have a frequency other than about 2.45 GHz, e.g., about 8.35 GHz, about 5.8 GHZ, about 1.98 GHz or about 915 MHz.
- the microwave supply unit 40 includes a multiple number of antenna modules 41 for introducing the microwaves split by the splitter 34 into the chamber 1 .
- Each antenna module 41 includes an amplifier unit 42 for amplifying the split microwave and a microwave introducing device 43 .
- the microwave introducing device 43 includes a tuner 60 for matching impedances and an antenna unit 45 for radiating the amplified microwave into the chamber 1 .
- the split microwave is radiated into the chamber 1 from the antenna unit 45 of the microwave introducing device 43 of each of the antenna modules 41 .
- the microwave supply unit 40 includes seven antenna modules 41 .
- six microwave introducing devices 43 are annularly arranged on the circular ceiling plate 110 , and one microwave introducing device 43 is provided at the center thereof.
- the ceiling plate 110 serves as a vacuum seal and a microwave transmitting plate.
- the ceiling plate 110 includes a metal frame 110 a and dielectric members 110 b provided at positions where the microwave introducing devices 43 are provided.
- Each dielectric member 110 b is made of a dielectric material such as quartz.
- the amplifier unit 42 includes a phase controller 46 , a variable gain amplifier 47 , a main amplifier 48 as a solid state amplifier and an isolator 49 .
- the phase controller 46 is capable of changing a phase of microwave.
- radiation property can be modulated.
- directivity can be controlled, and a plasma distribution can be varied.
- a phase of microwave for each antenna module by adjusting a phase of microwave for each antenna module, directivity can be controlled, and a plasma distribution can be varied.
- a phase of microwave for each antenna module by fixing a phase of microwave of a certain antenna module while continuously varying a phase of microwave of an antenna module adjacent thereto, it is possible to suppress a standing wave of the microwave.
- the variable gain amplifier 47 adjusts a power level of the microwave to be inputted to the main amplifier 48 . Further, the variable gain amplifier 47 also regulates plasma intensity or controls a difference between the respective antenna modules. By adjusting the variable gain amplifier 47 for each antenna module, a certain plasma distribution may be generated.
- the main amplifier 48 as the solid state amplifier may include, for example, an input matching circuit 131 , a semiconductor amplifying device 132 , an output matching circuit 133 and a high Q resonance circuit 134 .
- the isolator 49 separates microwave reflected from the antenna unit 45 and heading toward the main amplifier 48 .
- the isolator 49 includes a circulator and a dummy load (a coaxial terminator).
- the circulator sends the microwave reflected from the antenna unit 45 to the dummy load, and the dummy load converts the reflected microwave sent from the circulator into heat.
- the microwave introducing device 43 includes a coaxial waveguide 44 for transmitting microwave and the antenna unit 45 for radiating the microwave transmitted through the waveguide 44 into the chamber 1 .
- Microwaves radiated from the respective microwave introducing devices 43 into the chamber 1 are combined within the chamber 1 , so that surface wave plasma is generated within the chamber 1 .
- the waveguide 44 includes a cylindrical external conductor 52 and a rod-shaped internal conductor 53 .
- the external conductor 52 and the internal conductor 53 are coaxially arranged.
- the antenna unit 45 is positioned at a leading end of the waveguide 44 .
- the internal conductor 53 serves as a power supply, while the external conductor 52 is electrically grounded.
- a reflection plate 58 is provided at upper ends of the external conductor 52 and the internal conductor 53 .
- a power supply device 54 for supplying the microwave (electromagnetic wave) is provided at a side of the waveguide 44 .
- the power supply device 54 includes a microwave power inlet port 55 for introducing a microwave power.
- the microwave power inlet port 55 is provided at a side surface of the waveguide 44 (external conductor 52 ).
- the microwave power inlet port 55 is connected with a coaxial line 56 as a power supply line for supplying the microwave amplified by the amplifier unit 42 .
- the coaxial line 56 includes an internal conductor 56 a and an external conductor 56 b. Further, a leading end of the internal conductor 56 a of the coaxial line 56 is connected to a power supply antenna 90 horizontally extending toward the inside of the external conductor 52 .
- the power supply antenna 90 may be, for example, formed as a microstrip line on a PCB substrate as a print circuit.
- a wavelength shortening member 59 for shortening an effective wavelength of a reflection wave.
- the wavelength shortening member 59 may be made of a dielectric material such as Teflon (Registered Trademark).
- Teflon Registered Trademark
- the wavelength shortening member 59 may not be provided. Since the electromagnetic wave radiated from the power supply antenna 90 is reflected by the reflection plate 58 , a maximum amount of electromagnetic wave can be transmitted into the coaxial waveguide 44 .
- a distance from the power supply antenna 90 to the reflection plate 58 may be set to be multiples of half-wavelength of ⁇ g/4.
- the power supply antenna 90 includes an antenna main body 91 and a reflection member 94 .
- the antenna main body 91 includes a first pole 92 to which an electromagnetic wave is supplied and a second pole 93 for radiating the supplied electromagnetic wave. Further, the antenna main body 91 is connected to internal conductor 56 a of the coaxial line 56 at the microwave power inlet port 55 .
- the reflection member 94 has a ring shape and is extended along the outside of the internal conductor 53 from the both sides of the antenna main body 91 . In this configuration, the standing wave may be generated by the electromagnetic wave incident to the antenna main body 91 and the electromagnetic wave reflected from the reflection member 94 .
- the second pole 93 of the antenna main body 91 is in contact with the internal conductor 53 .
- the microwave power is supplied into a space between the external conductor 52 and the internal conductor 53 .
- the microwave power supplied to the power supply device 54 is propagated to the antenna unit 45 .
- the tuner 60 is provided in the waveguide 44 .
- the tuner 60 is configured to match load (plasma) impedance within the chamber 1 with characteristic impedance of the microwave power supply in the microwave output unit 30 .
- the tuner 60 includes two slugs 61 a and 61 b provided between the external conductor 52 and the internal conductor 53 ; and a slug driving unit 70 provided at the outside (top) of the reflection plate 58 . Further, the slugs 61 a and 61 b are vertically movable along the waveguide 44 .
- the slug 61 a is located on the side of the slug driving unit 70
- the slug 61 b is located on the side of the antenna unit 45 .
- Two slug moving shafts 64 a and 64 b for moving the slugs are provided within an internal space of the internal conductor 53 in a lengthwise direction of the internal conductor 53 .
- Each of the slug moving shafts 64 a and 64 b is formed of, e.g., a screw rod having a trapezoidal screw.
- the slug 61 a is made of a dielectric material and has a ring shape.
- a sliding member 63 made of resin having slidable property is fitted to the inside of the slug 61 a.
- the sliding member 63 has a screw hole 65 a into which the slug moving shaft 64 a is screwed; and a through hole 65 b through which the slug moving shaft 64 b is inserted.
- a sliding member 63 of the slug 61 b also has a screw hole 65 a and a through hole 65 b.
- the slug moving shaft 64 b is screwed into the screw hole 65 a of the sliding member 63 , and the slug moving shaft 64 a is inserted through the through hole 65 b of the sliding member 63 . Accordingly, by rotating the slug moving shaft 64 a, the slug 61 a is moved up and down, and by rotating the slug moving shaft 64 b, the slug 61 b is moved up and down. That is, the slugs 61 a and 61 b are moved up and down by a screw device including the slug moving shafts 64 a and 64 b and the sliding members 63 .
- the internal conductor 53 has three slits 53 a arranged at a regular interval, and the three slits 53 a are formed in a lengthwise direction thereof. Further, each of the sliding members 63 has three protrusions 63 a arranged at a regular interval so as to correspond to the three slits 53 a, respectively.
- the sliding members 63 are respectively fitted into the slugs 61 a and 61 b while the protrusions 63 a are in contact with the inner peripheries of the slugs 61 a and 61 b. Outer peripheral surfaces of the sliding members 63 are firmly in contact with inner peripheral surfaces of the internal conductor 53 .
- a width of each slit 53 a may be set to be equal to or smaller than about 5 mm.
- the sliding member 63 resin that can be easily fabricated and has fine slidable property may be used.
- resin polyphenylene sulfide (PPS) resin (Product name: BEAREE AS5000 (manufactured by NTN Co., Ltd.)) may be used.
- the slug moving shafts 64 a and 64 b are extended to the slug driving unit 70 through the reflection plate 58 .
- bearings are provided between the slug moving shafts 64 a and 64 b and the reflection plate 58 .
- a bearing 67 made of a conductor is provided at a lower end of the internal conductor 53 , and lower ends of the slug moving shafts 64 a and 64 b are supported on the bearing 67 .
- the slug driving unit 70 has a housing 71 .
- the slug moving shafts 64 a and 64 b are extended into the housing 71 .
- Gears 72 a and 72 b are fixed to upper ends of the slug moving shafts 64 a and 64 b, respectively.
- the slug driving unit 70 also includes a motor 73 a for rotating the slug moving shaft 64 a and a motor 73 b for rotating the slug moving shaft 64 b.
- a gear 74 a is fixed to a shaft of the motor 73 a
- a gear 74 b is fixed to a shaft of the motor 73 b.
- the gear 74 a is engaged with the gear 72 a
- the gear 74 b is engaged with the gear 72 b.
- the slug moving shaft 64 a is rotated by the motor 73 a via the gears 74 a and 72 a
- the slug moving shaft 64 b is rotated by the motor 73 b via the gears 74 b and 72 b.
- the motors 73 a and 73 b may be, e.g., stepping motors.
- the slug moving shaft 64 b is longer than the slug moving shaft 64 a such that the upper end of the slug moving shaft 64 b extends to a higher position than the upper end of the slung moving shaft 64 a. Accordingly, if the positions of the gears 72 a and 72 b are offset vertically, the motors 73 a and 73 b are also offset vertically. Thus, a space for power transmission units such as the motors and the gears can be reduced, and the housing 71 accommodating the power transmission units may have the same diameter as that of the external conductor 52 .
- Incremental encoders 75 a and 75 b for detecting positions of the slugs 61 a and 61 b are directly connected with output shafts of the motors 73 a and 73 b, respectively.
- the positions of the slugs 61 a and 61 b are controlled by a slug controller 68 .
- the slug controller 68 controls the positions of the slugs 61 a and 61 b by sending a control signal to the motors 73 a and 73 b. Accordingly, the impedance can be adjusted.
- the slug controller 68 performs impedance matching such that impedance of a termination end becomes, e.g., about 50 ⁇ . If only one of the two slugs is moved, a trajectory passing through an origin on a Smith chart is created. If both slugs are moved, only a phase is rotated.
- the antenna unit 45 includes a planar slot antenna 81 having slots 81 a and serving as a microwave radiation antenna. Further, the antenna unit 45 includes a wavelength shortening member 82 provided on a top surface of the planar slot antenna 81 . A cylindrical member 82 a made of a conductor is provided through the center of the wavelength shortening member 82 so as to connect the bearing 67 with the planar slot antenna 81 . Accordingly, the internal conductor 53 is connected with the planar slot antenna 81 via the bearing 67 and the cylindrical member 82 a. Further, a wavelength shortening member 83 is provided at a leading end side of the planar slot antenna 81 .
- a lower end of the external conductor 52 is extended up to the planar slot antenna 81 , and an outside of the wavelength shortening member 82 is covered with the external conductor 52 . Furthermore, outsides of the planar slot antenna 81 and the wavelength shortening member 83 are covered with a coating conductor 84 .
- Each of the wavelength shortening members 82 and 83 has a dielectric constant larger than that of a vacuum and is made of, e.g., quartz, ceramic, fluorine-based resin such as polytetrafluoroethylene, polyimide resin, or the like.
- a wavelength of microwave may be lengthened.
- each of the wavelength shortening members 82 and 83 serves to shorten the wavelength of the microwave so as to reduce a size of the antenna.
- the wavelength shortening members 82 and 83 can adjust the phase of the microwave depending on their thicknesses.
- the thicknesses of the wavelength shortening members 82 and 83 may be adjusted such that the planar slot antenna 81 becomes a portion corresponding to an antinode of a standing wave. In this way, reflection of the microwave can be decreased, and radiation energy of the planar slot antenna 81 can be increased.
- the wavelength shortening member 83 is in contact with the dielectric member 110 b inserted into the frame 110 a of the ceiling plate 110 .
- the microwave amplified by the main amplifier 48 is transmitted to the space between the internal conductor 53 and the external conductor 52 ; passed through the wavelength shortening member 83 and the dielectric member 110 b of the ceiling plate 110 from the slots 81 a of the planar slot antenna 81 ; and radiated into the space within the chamber 1 .
- the main amplifier 48 , the tuner 60 and the planar slot antenna 81 are located adjacent to each other.
- the tuner 60 and the planar slot antenna 81 form a lumped constant circuit existing within a 1 ⁇ 2 wavelength. Further, since a combined resistance of the planar slot antenna 81 and the wavelength shortening members 82 and 83 is set to be about 50 ⁇ , the tuner 60 can directly tune the plasma load. Accordingly, energy can be efficiently transferred to the plasma.
- Each component of the surface wave plasma processing apparatus 100 is controlled by a control unit 120 having a microprocessor.
- the control unit 120 may include a storage unit, an input unit, a display, and so forth.
- the storage unit stores therein process sequences of the surface wave plasma processing apparatus 100 and process recipes as control parameters.
- the control unit 120 controls the plasma processing apparatus according to a selected processing recipe.
- the wafer W is loaded into the chamber 1 and is mounted on the susceptor 11 .
- a plasma gas e.g., an Ar gas is introduced into the chamber 1 from the plasma gas supply source 27 through the pipe 28 and the plasma gas introducing member 26 , and microwave is introduced into the chamber 1 from the microwave plasma source 2 . Accordingly, surface wave plasma is generated within the chamber 1 .
- a processing gas e.g., an etching gas such as a Cl 2 gas is discharged from the processing gas supply source 25 into the chamber 1 via the pipe 24 and the shower plate 20 .
- the discharged processing gas is excited into plasma by the plasma that has passed through the spaces 23 of the shower plate 20 .
- a plasma process such as an etching process is performed on the wafer W.
- a microwave power oscillated by the microwave oscillator 32 of the microwave output unit 30 is amplified by the amplifier 33 , and the amplified microwave power is split by the splitter 34 in plural numbers. Then, the split microwave powers are sent to the microwave supply unit 40 .
- the split microwave powers are individually amplified by the main amplifiers 48 as the solid state amplifiers, and are supplied into the waveguides 44 of the microwave introducing devices 43 , respectively. In each of the waveguides 44 , impedances of the split microwave powers are automatically matched by the tuner 60 .
- the microwave powers are radiated into chamber 1 via the wavelength shortening member 82 , the planar slot antenna 81 , the wavelength shortening member 83 and the dielectric member 110 b of the ceiling plate 110 . Then, the split microwave powers are combined within the chamber 1 .
- an input phase of the microwave inputted to one of two adjacent microwave introducing devices 43 is fixed, while varying an input phase of the microwave inputted to the other microwave introducing device 43 according to a periodic waveform such as a sine waveform.
- input phases of the microwaves inputted to both of the two adjacent microwave introducing devices 43 may be varied according to periodic waveforms not overlapped with each other.
- input phases of the microwaves inputted to three microwave introducing devices 43 marked by slanting lines of FIG. 8 are varied according to a periodic waveform, while fixing input phases of the microwaves inputted to the rest microwave introducing devices 43 marked by a white color to about 0°.
- the periodic waveform is set to be a sine waveform
- the input phases of the microwaves inputted to two adjacent microwave introducing devices 43 are as shown in FIG. 9 .
- antinodes of a standing wave when the input phases of the microwaves inputted to the two adjacent microwave introducing devices 43 are all fixed to about 0° are changed nodes if the input phase of the microwave inputted to one of the adjacent microwave introducing devices 43 is varied by about 180°, or vice versa.
- the positions of the nodes and the antinodes of the standing wave may be varied continuously, so that electric field intensity can be uniformized, and uniformity of the electric field intensity on a wafer surface can also be improved. Accordingly, electron density, i.e., plasma density within the chamber 1 can be uniformized, so that a uniform plasma process can be performed.
- phase of the microwave inputted to each microwave introducing device 43 may be adjusted by the phase controller 46 of each antenna module 41 .
- Each phase controller 46 is controlled by the control unit 120 .
- the periodic waveform may not be limited to the sine waveform.
- a triangular waveform as shown in FIG. 10A or a trapezoidal waveform as shown in FIG. 10B may be used.
- the periodic waveform may not be limited to a perfect sine waveform.
- a waveform similar to a sine waveform an analogous sine waveform obtained by flattening a sine waveform at a phase around about 180°, as shown in FIG. 10C .
- a rectangular waveform may be also applicable, the rectangular waveform is not desirable because there is a portion where a differential value becomes infinite.
- FIG. 11A shows an electric field distribution when the input phases of the microwaves inputted to all the microwave introducing devices are fixed to about 0°.
- FIG. 11B shows an electric field distribution when the input phases of the microwaves inputted to the three outer microwave introducing devices are changed by about 180°.
- electric field intensity is indicated by different colors (black and white).
- bright circular ring-shaped portions indicate portions where the electric field intensity is high around the microwave introducing devices of the antenna modules. These portions correspond to antinodes of the standing wave. Further, among these portions, darker portions represent higher electric field intensity. Furthermore, portions between the adjacent microwave introducing devices show lower electric field intensity. These portions correspond to nodes of the standing wave. Specifically, portions surrounded by a dashed line in FIG. 11A correspond to the nodes of the standing wave.
- the electric field intensity changes greatly, as shown in FIG. 11B .
- the portions, surrounded by the dashed line in FIG. 11A correspond to the nodes of the standing wave. However, these portions are changed to the antinodes of the standing wave in FIG. 11B since the electric field intensity has been increased by changing the input phase of the microwave inputted to one of two adjacent microwave introducing devices by about 180°. That is, when the input phases of the microwaves inputted to all the microwave introducing devices 43 are fixed to about 0°, portions between adjacent microwave introducing devices 43 correspond the nodes of the standing wave.
- the input phase of the microwave inputted to one of two adjacent microwave introducing devices is fixed, while varying the input phase of the microwave inputted to the other microwave introducing device according to the periodic waveform such as a sine waveform.
- the input phases of the microwaves inputted to both of the two adjacent microwave introducing devices 43 may be varied according to periodic waveforms not overlapped with each other.
- all of the microwave introducing devices need not satisfy these conditions.
- only a part of these sets may satisfy these conditions.
- a ceiling plate has a different configuration.
- FIG. 12 illustrates a plane view schematically illustrating a ceiling plate and a microwave introducing device of a microwave plasma source in accordance with the second embodiment.
- FIG. 13 is a cross sectional view taken along a line CC′ of FIG. 12 .
- a circular ceiling plate 110 in accordance with the second embodiment includes dielectric members 110 b fitted to positions where a multiple number of microwave introducing devices 43 for radiating microwaves into the chamber 1 are provided.
- Each dielectric member 110 b is made of a dielectric material such as quartz and has a hexagon shape. Adjacent dielectric members 110 b are placed close to each other such that one side of a hexagon faces to one side of other hexagon.
- a metal frame 110 a supporting the dielectric members 110 b has a honeycomb structure. Portions of the metal frame 110 a between the adjacent dielectric members 110 b have narrow straight lines shapes.
- the frame 110 a has supporting members 110 c for supporting the dielectric members 110 b.
- the ceiling plate 110 serves to transmit the microwaves as stated above.
- the entire ceiling plate 110 may be made of a dielectric material.
- the microwaves are radiated from the multiple number of microwave introducing devices 43 as in the microwave plasma source in accordance with the present embodiment, if the entire ceiling plate 110 is made of the dielectric material such as quartz, all the microwaves radiated from a certain microwave introducing device 43 may not be introduced into the chamber 1 but a part of the microwaves may reach another microwave introducing device 43 through the ceiling plate 110 . In such a case, the microwave radiated from the certain microwave introducing device 43 and the microwave radiated from the another microwave introducing device 43 may interfere with each other. Further, if the entire ceiling plate 110 is made of the dielectric material, there may also be various other problems. By way of example, a mode jump of plasma may occur easily or strength of a dielectric member may become decreased.
- the dielectric members are provided only at positions where the microwave introducing devices 43 of the antenna modules 41 are placed, and other portions of the ceiling plate 110 have the metal frame for supporting the dielectric members.
- Each dielectric member may have a circular shape as in the first embodiment or may have a rectangular shape or a square shape.
- the dielectric members have circular shapes, however, the area of metal frame between the adjacent dielectric members would be increased and, thus, area occupied by the dielectric members may be reduced. In such a case, a microwave radiation area may also be reduced, making it difficult to generate plasma efficiently. Furthermore, when the dielectric members have rectangular shapes or square shapes, strength of the ceiling plate 110 may be decreased.
- the frame 110 a of the ceiling plate 110 to have the honeycomb structure and the dielectric members 110 b to have the hexagon shapes, the area of the ceiling plate 110 occupied by the dielectric members 110 b can be increased.
- the microwave radiation area can be increased and the plasma can be generated efficiently.
- the frame 110 a to have the honeycomb structure the strength of the ceiling plate 110 can be increased.
- the frame 110 a may not have a perfect honeycomb structure but it may have a structure similar to the honeycomb structure.
- outer peripheries of the dielectric members 110 b corresponding to outer microwave introducing devices 43 may be protruded outward. In such a configuration, the areas of the dielectric members 110 b can be more increased.
- the frame 110 a may have a honeycomb structure and a honeycomb-shaped structure including a structure similar to the honeycomb structure.
- a multiple number of gas discharge holes 112 may be formed at the frame 110 a of the ceiling plate 110 so as to discharge a plasma gas such as an Ar gas, as in a shower device.
- a gas flow path may be formed inside the frame 110 a of the ceiling plate 110 , and the plasma gas supply source 27 may be connected to the gas flow path via, e.g., the pipe 28 .
- the plasma gas such as the Ar gas may be uniformly discharged from the gas discharge holes 112 . Accordingly, the Ar gas can be excited into plasma promptly, so that uniform plasma can be generated.
- the effects of the second embodiment can be more enhanced when the second embodiment is combined with the first embodiment.
- the aforementioned effects of the second embodiment can be achieved even if the first embodiment is not combined.
- the present disclosure may not be limited to the above-described embodiment and can be modified in various ways.
- the circuit configuration of the microwave output unit, or the circuit configuration of the microwave supply unit and the main amplifier may not be limited to the above-described embodiments.
- the microwave introducing device may also not be limited to those described in the embodiments.
- the microwave introducing device may have various configurations as long as it can radiate a microwave appropriately.
- the number or the arrangement of the microwave introducing devices may not be limited to the above embodiments.
- the etching apparatus is used as the plasma processing apparatus.
- the present disclosure is not limited thereto and may be applicable to various other plasma processes such as a film forming process, an oxynitriding process, an asking process or the like.
- the processing target substrate is not limited to the semiconductor wafer, and various other types of substrates such as a FPD (Flat Panel Display) represented by an LCD (Liquid Crystal Display) and a ceramic substrate may be adopted.
Abstract
There are provided a microwave plasma source and a plasma processing apparatus capable of improving uniformity of a plasma density distribution within a processing chamber by controlling positions of nodes and antinodes of a standing wave of microwave within the processing chamber not to be fixed. The microwave plasma source 2 includes a microwave supply unit 40. The microwave supply unit 40 includes multiple microwave introducing devices 43 each introducing microwave into the processing chamber; and multiple phase controllers 46 for adjusting phases of the microwaves inputted to the microwave introducing devices 43. Here, the phases of the microwaves inputted to the microwave introducing devices 43 are adjusted by fixing an input phase of the microwave inputted to one of two adjacent microwave introducing devices 43 while varying an input phase of the microwave inputted to the other microwave introducing device 43 according to a periodic waveform.
Description
- This application claims the benefit of Japanese Patent Application No. 2010-234688 filed on Oct. 19, 2010, the entire disclosures of which are incorporated herein by reference in their entirety.
- The present disclosure relates to a microwave plasma source and a plasma processing apparatus using the same.
- In a manufacturing process of a semiconductor device or a liquid crystal display, a plasma processing apparatus such as a plasma etching apparatus or a plasma CVD apparatus has been used for performing a plasma process such as an etching process or a film forming process on a processing target substrate such as a semiconductor wafer or a glass substrate.
- Recently, as such a plasma processing apparatus, a RLSA (Radial Line Slot Antenna) microwave plasma processing apparatus capable of uniformly generating high-density surface wave plasma having a low electron temperature is attracting attention (see, for example, Patent Document 1).
- The RLSA microwave plasma processing apparatus includes a planar antenna (radial line slot antenna) having slots formed in a certain pattern. The planar antenna is provided in an upper portion of a chamber (processing vessel). Microwave induced from a microwave generation source through a coaxial waveguide is radiated into the chamber from the slots of the planar antenna. A gas introduced into the chamber is excited into plasma by a microwave electric field. Accordingly, a plasma process is performed on a processing target object such as a semiconductor wafer.
- In order to adjust a plasma distribution in such a RLSA microwave plasma processing apparatus, it is required to provide a multiple number of antennas each having a different slot shape and pattern, and to exchange the antennas. In this case, processes become more complicated.
- In order to solve this problem, described in
Patent Document 2 is a microwave plasma source that splits microwave into a multiple number of microwaves, radiates the split microwaves into a chamber through a multiple number of antenna modules and combines the split microwaves in a space within the chamber. - As described above, by combining the microwaves in the space within the chamber by using the multiple number of antenna modules, phases or intensity of the microwaves radiated from the antennas of the antenna modules can be adjusted. As a result, the plasma distribution can also be adjusted.
- Patent Document 1: Japanese Patent Laid-open Publication No. 2000-294550
- Patent Document 2: Pamphlet of International Patent Publication No. 2008/013112
- However, when the plasma is generated by radiating the microwaves into the chamber through the multiple number of antenna modules, antinodes and nodes of a standing wave generated when the microwaves are radiated into the chamber can occur. The antinodes and the nodes of the standing wave may cause non-uniformity of an electron density distribution in the plasma. As a result, a plasma density distribution may not become uniformized.
- In view of the foregoing, the present disclosure provides a microwave plasma source capable of controlling positions of nodes and antinodes of a standing wave of microwave within the processing chamber not to be fixed and improving uniformity of a plasma density distribution within the processing chamber. Further, the present disclosure also provides a plasma processing apparatus using the microwave plasma source.
- In accordance with a first aspect of the present disclosure, there is provided a microwave plasma source for introducing microwave into a processing chamber capable of performing a plasma process by exciting a gas supplied into the processing chamber into plasma by the microwave. The microwave plasma source includes a microwave generator for generating microwave; and a microwave supply unit configured to supply the generated microwave into the processing chamber. The microwave supply unit includes a multiple number of microwave introducing devices each introducing the microwave into the processing chamber; and a multiple number of phase controllers for adjusting phases of the microwaves input to the multiple number of microwave introducing devices. Here, the phases of the microwaves may be adjusted by fixing an input phase of the microwave input to one of two adjacent microwave introducing devices while varying an input phase of the microwave input to the other microwave introducing device according to a periodic waveform. Alternatively, the phases of the microwaves may be adjusted by varying input phases of the microwaves input to both of the two adjacent microwave introducing devices according to periodic waveforms not overlapped with each other.
- The periodic waveform may be one of a sine waveform, a triangular waveform, a trapezoidal waveform and a waveform similar to a sine waveform.
- Further, the microwave plasma source may further include a ceiling plate serving as a top wall of the processing chamber and configured to transmit the microwaves radiated from the multiple number of microwave introducing devices. Here, the ceiling plate may include a multiple number of dielectric members provided at positions corresponding to the multiple number of microwave introducing devices; and a metal frame, having a honeycomb structure, for supporting the dielectric members. The frame may have a gas flow path and a multiple number of gas discharge holes. Further, a gas used for the plasma process may be discharged into the processing chamber from the gas discharge holes.
- In accordance with a second aspect of the present disclosure, there is provided a plasma processing apparatus including a processing chamber for accommodating therein a processing target substrate; a mounting table for mounting thereon the processing target substrate within the processing chamber; a gas supply unit for supplying a gas into the processing chamber; and the aforementioned microwave plasma source. Here, plasma may be generated by microwave introduced into the processing chamber from the microwave plasma source. Further, a process may be performed on the processing target substrate by the plasma.
- In accordance with the present disclosure, the phases of the microwaves may be adjusted by fixing the input phase of the microwave inputted to one of two adjacent microwave introducing devices while varying the input phase of the microwave inputted to the other microwave introducing device according to the periodic waveform. Alternatively, the phases of the microwaves may be adjusted by varying input phases of the microwaves inputted to both of the two adjacent microwave introducing devices according to periodic waveforms not overlapped with each other. Accordingly, by continuously changing the positions of the nodes and the antinodes of the standing wave generated when the microwaves are radiated into the processing chamber, it may be possible to uniformize electric field intensity and to improve in-plane uniformity of the electric field intensity. As a result, an electron density, i.e., a plasma density within the processing chamber can be uniformized, and a uniform plasma process can be performed.
- Non-limiting and non-exhaustive embodiments will be described in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be intended to limit its scope, the disclosure will be described with specificity and detail through use of the accompanying drawings, in which:
-
FIG. 1 is a cross sectional view illustrating a schematic configuration of a surface wave plasma processing apparatus having a microwave plasma source in accordance with a first embodiment of the present disclosure; -
FIG. 2 is a configuration view of the microwave plasma source; -
FIG. 3 is a plane view schematically illustrating a microwave supply unit of the microwave plasma source; -
FIG. 4 shows an example circuit configuration of a main amplifier of an antenna module of the microwave plasma source; -
FIG. 5 is a cross sectional view illustrating a microwave introducing device of the antenna module of the microwave plasma source; -
FIG. 6 is a transversal cross sectional view taken along a line AA′ ofFIG. 5 , and shows a power supply unit of the microwave introducing device; -
FIG. 7 is a transversal cross sectional view taken along a line BB′ ofFIG. 5 , and shows a slug and a sliding member of a tuner; -
FIG. 8 is a schematic diagram for describing a case where input phases of microwaves inputted to three microwave introducing devices among seven microwave introducing devices of the microwave plasma source are varied according to a periodic waveform; -
FIG. 9 shows an input phase with time when an input phase of microwave inputted to one of adjacent microwave introducing devices is fixed to 0° while varying an input phase of microwave inputted to the other microwave introducing device according to a sine waveform; -
FIGS. 10A to 10C show example periodic waveforms other than a sine waveform; -
FIGS. 11A and 11B respectively show analysis results of electric field distributions within a chamber in a case where input phases of microwaves inputted to all of the seven microwave introducing devices of the microwave plasma source shown inFIG. 3 are set to be about 0° and in a case where input phases of microwaves inputted to three outer microwave introducing devices are changed by about 180°; -
FIG. 12 is a plane view schematically illustrating a microwave supply unit and a ceiling plate of a microwave plasma source in accordance with a second embodiment of the present disclosure. -
FIG. 13 is a cross sectional view taken along a line CC′ ofFIG. 12 ; -
FIG. 14 is a plane view schematically illustrating a modification example of the ceiling plate; and -
FIG. 15 is a bottom view illustrating another modification example of the ceiling plate. - Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.
-
FIG. 1 is a cross sectional view illustrating a schematic configuration of a surface wave plasma processing apparatus having a microwave plasma source in accordance with a first embodiment of the present disclosure.FIG. 2 is a configuration view of the microwave plasma source.FIG. 3 is a plane view schematically illustrating a microwave supply unit of the microwave plasma source.FIG. 4 shows an example circuit configuration of a main amplifier of an antenna module of the microwave plasma source.FIG. 5 is a cross sectional view illustrating a microwave introducing device of the antenna module of the microwave plasma source.FIG. 6 is a transversal cross sectional view taken along a line AA′ ofFIG. 5 , and shows a power supply unit of the microwave introducing device.FIG. 7 is a transversal cross sectional view taken along a line BB′ ofFIG. 5 , and shows a slug and a sliding member of a tuner. - A surface wave
plasma processing apparatus 100 is configured as a plasma etching apparatus that performs a plasma process such as an etching process on a wafer. The surface waveplasma processing apparatus 100 may include a substantiallycylindrical chamber 1 and amicrowave plasma source 2 for generating microwave plasma within thechamber 1. Thechamber 1 is made of a metal material such as aluminum or stainless steel, and is airtightly sealed. Further, thechamber 1 is electrically grounded. Anopening 1 a may be formed at a top portion of thechamber 1, and themicrowave plasma source 2 is provided in the opening la so as to face the inside of thechamber 1. - A
susceptor 11 for horizontally mounting thereon a wafer W as a processing target object is provided within thechamber 1. Thesusceptor 11 is supported on acylindrical supporting member 12 that is provided at a center of a bottom of thechamber 1 via an insulatingmember 12 a. Thesusceptor 11 and the supportingmember 12 may be made of, e.g., aluminum having an alumite-treated (anodically oxidized) surface. - Although not illustrated, if necessary, the
susceptor 11 may include an electrostatic chuck for electrostatically attracting the wafer W, a temperature control device, a gas flow path for supplying a heat transfer gas to a rear surface of the wafer W and a vertically movable elevating pin for transferring the wafer W. Further, thesusceptor 11 is electrically connected with a high frequencybias power supply 14 via amatching unit 13. A high frequency power is supplied to the susceptor 11 from the high frequencybias power supply 14, so that ions in the plasma may be attracted toward the wafer W. - A
gas exhaust pipe 15 is connected to the bottom of thechamber 1, and agas exhaust unit 16 including a vacuum pump is connected with thegas exhaust pipe 15. By operating thegas exhaust unit 16, thechamber 1 is evacuated, so that the inside of thechamber 1 can be depressurized to a certain vacuum level at a high speed. Furthermore, a loading/unloadingport 17 for loading and unloading the wafer W and agate valve 18 for opening and closing the loading/unloadingport 17 are provided at a sidewall of thechamber 1. - A
shower plate 20 for discharging a processing gas for plasma etching toward the wafer W is horizontally provided above thesusceptor 11 within thechamber 1. Theshower plate 20 includes a lattice-shapedgas flow path 21 and a multiple number of gas discharge holes 22 formed in thegas flow path 21. There existspaces 23 between lattice patterns of thegas flow path 21. An outwardly extendingpipe 24 is connected to thegas flow path 21 of theshower plate 20. Thepipe 24 is connected with a processinggas supply source 25. - Further, a ring-shaped plasma gas introducing member is provided along the sidewall of the
chamber 1 at a position above theshower plate 20 of thechamber 1, and a multiple number of gas discharge holes are formed at an inner periphery of the plasmagas introducing member 26. The plasmagas introducing member 26 is connected to a plasmagas supply source 27 for supplying the plasma gas via apipe 28. A rare gas such as an Ar gas may be used as the plasma gas. - The plasma gas introduced into the
chamber 1 from the plasmagas introducing member 26 is excited into plasma by the microwave introduced into thechamber 1 from themicrowave plasma source 2. This plasma travels in thespaces 23 of theshower plate 20 and excites the processing gas discharged from the gas discharge holes 22 of theshower plate 20. As a result, plasma of the processing gas is generated. - The
microwave plasma source 2 is provided on aceiling plate 110 supported by a supportingring 29 placed at the upper portion of thechamber 1. A gap between the supportingring 29 and theceiling plate 110 is hermetically sealed. As illustrated inFIG. 2 , themicrowave plasma source 2 includes amicrowave output unit 30 for splitting and outputting microwaves and amicrowave supply unit 40 for guiding and radiating the microwaves outputted into thechamber 1 from themicrowave output unit 30. - The
microwave output unit 30 includes amicrowave power supply 31, amicrowave oscillator 32, anamplifier 33 and asplitter 34. Theamplifier 33 amplifies the oscillated microwave, and thesplitter 34 splits the amplified microwave in plural numbers. - The
microwave oscillator 32 oscillates microwave of a certain frequency (e.g., about 2.45 GHz), by way of example, by PLL (Phase Locked Loop). Thesplitter 34 splits the microwave amplified by theamplifier 33 while matching input impedance with output impedance so as to reduce a loss of the microwave. Here, the microwave may have a frequency other than about 2.45 GHz, e.g., about 8.35 GHz, about 5.8 GHZ, about 1.98 GHz or about 915 MHz. - The
microwave supply unit 40 includes a multiple number ofantenna modules 41 for introducing the microwaves split by thesplitter 34 into thechamber 1. Eachantenna module 41 includes anamplifier unit 42 for amplifying the split microwave and amicrowave introducing device 43. Further, themicrowave introducing device 43 includes atuner 60 for matching impedances and anantenna unit 45 for radiating the amplified microwave into thechamber 1. The split microwave is radiated into thechamber 1 from theantenna unit 45 of themicrowave introducing device 43 of each of theantenna modules 41. As depicted inFIG. 3 , themicrowave supply unit 40 includes sevenantenna modules 41. Here, sixmicrowave introducing devices 43 are annularly arranged on thecircular ceiling plate 110, and onemicrowave introducing device 43 is provided at the center thereof. Theceiling plate 110 serves as a vacuum seal and a microwave transmitting plate. Theceiling plate 110 includes ametal frame 110 a anddielectric members 110 b provided at positions where themicrowave introducing devices 43 are provided. Eachdielectric member 110 b is made of a dielectric material such as quartz. - The
amplifier unit 42 includes aphase controller 46, avariable gain amplifier 47, amain amplifier 48 as a solid state amplifier and anisolator 49. - The
phase controller 46 is capable of changing a phase of microwave. By thephase controller 46, radiation property can be modulated. By way of example, by adjusting a phase of microwave for each antenna module, directivity can be controlled, and a plasma distribution can be varied. In the present embodiment, as will be described later, by fixing a phase of microwave of a certain antenna module while continuously varying a phase of microwave of an antenna module adjacent thereto, it is possible to suppress a standing wave of the microwave. - The
variable gain amplifier 47 adjusts a power level of the microwave to be inputted to themain amplifier 48. Further, thevariable gain amplifier 47 also regulates plasma intensity or controls a difference between the respective antenna modules. By adjusting thevariable gain amplifier 47 for each antenna module, a certain plasma distribution may be generated. - As shown in
FIG. 4 , themain amplifier 48 as the solid state amplifier may include, for example, aninput matching circuit 131, asemiconductor amplifying device 132, anoutput matching circuit 133 and a highQ resonance circuit 134. - The
isolator 49 separates microwave reflected from theantenna unit 45 and heading toward themain amplifier 48. Theisolator 49 includes a circulator and a dummy load (a coaxial terminator). The circulator sends the microwave reflected from theantenna unit 45 to the dummy load, and the dummy load converts the reflected microwave sent from the circulator into heat. - Now, the
microwave introducing device 43 will be explained. - As depicted in
FIGS. 5 and 6 , themicrowave introducing device 43 includes acoaxial waveguide 44 for transmitting microwave and theantenna unit 45 for radiating the microwave transmitted through thewaveguide 44 into thechamber 1. Microwaves radiated from the respectivemicrowave introducing devices 43 into thechamber 1 are combined within thechamber 1, so that surface wave plasma is generated within thechamber 1. - The
waveguide 44 includes a cylindricalexternal conductor 52 and a rod-shapedinternal conductor 53. Theexternal conductor 52 and theinternal conductor 53 are coaxially arranged. Theantenna unit 45 is positioned at a leading end of thewaveguide 44. In thewaveguide 44, theinternal conductor 53 serves as a power supply, while theexternal conductor 52 is electrically grounded. Areflection plate 58 is provided at upper ends of theexternal conductor 52 and theinternal conductor 53. - A
power supply device 54 for supplying the microwave (electromagnetic wave) is provided at a side of thewaveguide 44. Thepower supply device 54 includes a microwavepower inlet port 55 for introducing a microwave power. The microwavepower inlet port 55 is provided at a side surface of the waveguide 44 (external conductor 52). The microwavepower inlet port 55 is connected with acoaxial line 56 as a power supply line for supplying the microwave amplified by theamplifier unit 42. Thecoaxial line 56 includes aninternal conductor 56 a and anexternal conductor 56 b. Further, a leading end of theinternal conductor 56 a of thecoaxial line 56 is connected to apower supply antenna 90 horizontally extending toward the inside of theexternal conductor 52. - The
power supply antenna 90 may be, for example, formed as a microstrip line on a PCB substrate as a print circuit. Provided in a gap between thereflection plate 58 and thepower supply antenna 90 is awavelength shortening member 59 for shortening an effective wavelength of a reflection wave. Thewavelength shortening member 59 may be made of a dielectric material such as Teflon (Registered Trademark). Here, when microwave having a high frequency of, e.g., about 2.45 GHz is used, thewavelength shortening member 59 may not be provided. Since the electromagnetic wave radiated from thepower supply antenna 90 is reflected by thereflection plate 58, a maximum amount of electromagnetic wave can be transmitted into thecoaxial waveguide 44. Here, a distance from thepower supply antenna 90 to thereflection plate 58 may be set to be multiples of half-wavelength of λg/4. - As shown in
FIG. 6 , thepower supply antenna 90 includes an antennamain body 91 and areflection member 94. The antennamain body 91 includes afirst pole 92 to which an electromagnetic wave is supplied and asecond pole 93 for radiating the supplied electromagnetic wave. Further, the antennamain body 91 is connected tointernal conductor 56 a of thecoaxial line 56 at the microwavepower inlet port 55. Thereflection member 94 has a ring shape and is extended along the outside of theinternal conductor 53 from the both sides of the antennamain body 91. In this configuration, the standing wave may be generated by the electromagnetic wave incident to the antennamain body 91 and the electromagnetic wave reflected from thereflection member 94. Thesecond pole 93 of the antennamain body 91 is in contact with theinternal conductor 53. - As the
power supply antenna 90 radiates the microwave (electromagnetic wave), the microwave power is supplied into a space between theexternal conductor 52 and theinternal conductor 53. The microwave power supplied to thepower supply device 54 is propagated to theantenna unit 45. - Furthermore, the
tuner 60 is provided in thewaveguide 44. Thetuner 60 is configured to match load (plasma) impedance within thechamber 1 with characteristic impedance of the microwave power supply in themicrowave output unit 30. Thetuner 60 includes twoslugs external conductor 52 and theinternal conductor 53; and aslug driving unit 70 provided at the outside (top) of thereflection plate 58. Further, theslugs waveguide 44. - Among these slugs, the
slug 61 a is located on the side of theslug driving unit 70, while theslug 61 b is located on the side of theantenna unit 45. Twoslug moving shafts internal conductor 53 in a lengthwise direction of theinternal conductor 53. Each of theslug moving shafts - As shown in
FIG. 7 , theslug 61 a is made of a dielectric material and has a ring shape. A slidingmember 63 made of resin having slidable property is fitted to the inside of theslug 61 a. The slidingmember 63 has ascrew hole 65 a into which theslug moving shaft 64 a is screwed; and a throughhole 65 b through which theslug moving shaft 64 b is inserted. Like theslug 61 a, a slidingmember 63 of theslug 61 b also has ascrew hole 65 a and a throughhole 65 b. However, unlike theslug 61 a, theslug moving shaft 64 b is screwed into thescrew hole 65 a of the slidingmember 63, and theslug moving shaft 64 a is inserted through the throughhole 65 b of the slidingmember 63. Accordingly, by rotating theslug moving shaft 64 a, theslug 61 a is moved up and down, and by rotating theslug moving shaft 64 b, theslug 61 b is moved up and down. That is, theslugs slug moving shafts members 63. - The
internal conductor 53 has threeslits 53 a arranged at a regular interval, and the threeslits 53 a are formed in a lengthwise direction thereof. Further, each of the slidingmembers 63 has threeprotrusions 63 a arranged at a regular interval so as to correspond to the threeslits 53 a, respectively. The slidingmembers 63 are respectively fitted into theslugs protrusions 63 a are in contact with the inner peripheries of theslugs members 63 are firmly in contact with inner peripheral surfaces of theinternal conductor 53. As theslug moving shafts members 63 are moved up and down while being slid on theinternal conductor 53. That is, the inner peripheral surfaces of theinternal conductor 53 serves as a sliding guide of theslugs internal conductor 53 can be substantially removed, and, thus, radiation efficiency of the microwave power can maintains high. - As the sliding
member 63, resin that can be easily fabricated and has fine slidable property may be used. By way of example, polyphenylene sulfide (PPS) resin (Product name: BEAREE AS5000 (manufactured by NTN Co., Ltd.)) may be used. - The
slug moving shafts slug driving unit 70 through thereflection plate 58. Although not shown, bearings are provided between theslug moving shafts reflection plate 58. Further, abearing 67 made of a conductor is provided at a lower end of theinternal conductor 53, and lower ends of theslug moving shafts bearing 67. - The
slug driving unit 70 has ahousing 71. Theslug moving shafts housing 71.Gears slug moving shafts slug driving unit 70 also includes amotor 73 a for rotating theslug moving shaft 64 a and amotor 73 b for rotating theslug moving shaft 64 b. Agear 74 a is fixed to a shaft of themotor 73 a, and agear 74 b is fixed to a shaft of themotor 73 b. Thegear 74 a is engaged with thegear 72 a, and thegear 74 b is engaged with thegear 72 b. With this configuration, theslug moving shaft 64 a is rotated by themotor 73 a via thegears slug moving shaft 64 b is rotated by themotor 73 b via thegears motors - Moreover, the
slug moving shaft 64 b is longer than theslug moving shaft 64 a such that the upper end of theslug moving shaft 64 b extends to a higher position than the upper end of theslung moving shaft 64 a. Accordingly, if the positions of thegears motors housing 71 accommodating the power transmission units may have the same diameter as that of theexternal conductor 52. -
Incremental encoders slugs motors - The positions of the
slugs slug controller 68. To elaborate, based on an impedance magnitude of an input terminal detected by a non-illustrated impedance detector and position information of theslugs encoders slug controller 68 controls the positions of theslugs motors slug controller 68 performs impedance matching such that impedance of a termination end becomes, e.g., about 50 Ω. If only one of the two slugs is moved, a trajectory passing through an origin on a Smith chart is created. If both slugs are moved, only a phase is rotated. - The
antenna unit 45 includes aplanar slot antenna 81 havingslots 81 a and serving as a microwave radiation antenna. Further, theantenna unit 45 includes awavelength shortening member 82 provided on a top surface of theplanar slot antenna 81. Acylindrical member 82 a made of a conductor is provided through the center of thewavelength shortening member 82 so as to connect thebearing 67 with theplanar slot antenna 81. Accordingly, theinternal conductor 53 is connected with theplanar slot antenna 81 via thebearing 67 and thecylindrical member 82 a. Further, awavelength shortening member 83 is provided at a leading end side of theplanar slot antenna 81. Further, a lower end of theexternal conductor 52 is extended up to theplanar slot antenna 81, and an outside of thewavelength shortening member 82 is covered with theexternal conductor 52. Furthermore, outsides of theplanar slot antenna 81 and thewavelength shortening member 83 are covered with acoating conductor 84. - Each of the
wavelength shortening members wavelength shortening members wavelength shortening members wavelength shortening members planar slot antenna 81 becomes a portion corresponding to an antinode of a standing wave. In this way, reflection of the microwave can be decreased, and radiation energy of theplanar slot antenna 81 can be increased. - The
wavelength shortening member 83 is in contact with thedielectric member 110 b inserted into theframe 110 a of theceiling plate 110. The microwave amplified by themain amplifier 48 is transmitted to the space between theinternal conductor 53 and theexternal conductor 52; passed through thewavelength shortening member 83 and thedielectric member 110 b of theceiling plate 110 from theslots 81 a of theplanar slot antenna 81; and radiated into the space within thechamber 1. - In the present embodiment, the
main amplifier 48, thetuner 60 and theplanar slot antenna 81 are located adjacent to each other. Thetuner 60 and theplanar slot antenna 81 form a lumped constant circuit existing within a ½ wavelength. Further, since a combined resistance of theplanar slot antenna 81 and thewavelength shortening members tuner 60 can directly tune the plasma load. Accordingly, energy can be efficiently transferred to the plasma. - Each component of the surface wave
plasma processing apparatus 100 is controlled by acontrol unit 120 having a microprocessor. Thecontrol unit 120 may include a storage unit, an input unit, a display, and so forth. The storage unit stores therein process sequences of the surface waveplasma processing apparatus 100 and process recipes as control parameters. Thecontrol unit 120 controls the plasma processing apparatus according to a selected processing recipe. - Now, an operation of the surface wave
plasma processing apparatus 100 having the above-described configuration will be explained. First, the wafer W is loaded into thechamber 1 and is mounted on thesusceptor 11. Then, a plasma gas, e.g., an Ar gas is introduced into thechamber 1 from the plasmagas supply source 27 through thepipe 28 and the plasmagas introducing member 26, and microwave is introduced into thechamber 1 from themicrowave plasma source 2. Accordingly, surface wave plasma is generated within thechamber 1. - After the surface wave plasma is generated, a processing gas, e.g., an etching gas such as a Cl2 gas is discharged from the processing
gas supply source 25 into thechamber 1 via thepipe 24 and theshower plate 20. The discharged processing gas is excited into plasma by the plasma that has passed through thespaces 23 of theshower plate 20. By using the plasma of the processing gas, a plasma process such as an etching process is performed on the wafer W. - When the surface wave plasma is generated, in the
microwave plasma source 2, a microwave power oscillated by themicrowave oscillator 32 of themicrowave output unit 30 is amplified by theamplifier 33, and the amplified microwave power is split by thesplitter 34 in plural numbers. Then, the split microwave powers are sent to themicrowave supply unit 40. In themicrowave supply unit 40, the split microwave powers are individually amplified by themain amplifiers 48 as the solid state amplifiers, and are supplied into thewaveguides 44 of themicrowave introducing devices 43, respectively. In each of thewaveguides 44, impedances of the split microwave powers are automatically matched by thetuner 60. Then, without power reflection, the microwave powers are radiated intochamber 1 via thewavelength shortening member 82, theplanar slot antenna 81, thewavelength shortening member 83 and thedielectric member 110 b of theceiling plate 110. Then, the split microwave powers are combined within thechamber 1. - At this time, when an input phase of each microwave inputted into the
microwave introducing device 43 is fixed to, e.g., about 0°, positions of nodes and antinodes of a standing wave generated when the microwave is radiated into thechamber 1 are fixed. Accordingly, electron density of the plasma may be non-uniform, resulting in deterioration of uniformity of a plasma density distribution. - To solve the problem, in the present embodiment, an input phase of the microwave inputted to one of two adjacent
microwave introducing devices 43 is fixed, while varying an input phase of the microwave inputted to the othermicrowave introducing device 43 according to a periodic waveform such as a sine waveform. Alternatively, input phases of the microwaves inputted to both of the two adjacentmicrowave introducing devices 43 may be varied according to periodic waveforms not overlapped with each other. - By way of example, input phases of the microwaves inputted to three
microwave introducing devices 43 marked by slanting lines ofFIG. 8 are varied according to a periodic waveform, while fixing input phases of the microwaves inputted to the restmicrowave introducing devices 43 marked by a white color to about 0°. Here, if the periodic waveform is set to be a sine waveform, the input phases of the microwaves inputted to two adjacentmicrowave introducing devices 43 are as shown inFIG. 9 . Further, antinodes of a standing wave when the input phases of the microwaves inputted to the two adjacentmicrowave introducing devices 43 are all fixed to about 0° are changed nodes if the input phase of the microwave inputted to one of the adjacentmicrowave introducing devices 43 is varied by about 180°, or vice versa. In this way, by periodically varying the input phases of the microwaves, the positions of the nodes and the antinodes of the standing wave may be varied continuously, so that electric field intensity can be uniformized, and uniformity of the electric field intensity on a wafer surface can also be improved. Accordingly, electron density, i.e., plasma density within thechamber 1 can be uniformized, so that a uniform plasma process can be performed. - At this time, the phase of the microwave inputted to each
microwave introducing device 43 may be adjusted by thephase controller 46 of eachantenna module 41. Eachphase controller 46 is controlled by thecontrol unit 120. - The periodic waveform may not be limited to the sine waveform. By way of example, a triangular waveform as shown in
FIG. 10A or a trapezoidal waveform as shown inFIG. 10B may be used. Moreover, the periodic waveform may not be limited to a perfect sine waveform. For example, in order to increase time during which a phase is about 180°, there may be used a waveform similar to a sine waveform (an analogous sine waveform) obtained by flattening a sine waveform at a phase around about 180°, as shown inFIG. 10C . Further, although a rectangular waveform may be also applicable, the rectangular waveform is not desirable because there is a portion where a differential value becomes infinite. - Actually, by using the microwave plasma source including seven microwave introducing devices as shown in
FIG. 3 , an electric field distribution within the chamber is investigated for each of cases where the input phases of the microwaves inputted to all the microwave introducing devices are fixed to about 0° and where three microwave introducing devices among six outer microwave introducing devices are changed by about 180°. Here, a pressure within the chamber is set to be about 0.5 Torr and a microwave power is set to be about 200 W. The result is shown inFIGS. 11A and 11B .FIG. 11A shows an electric field distribution when the input phases of the microwaves inputted to all the microwave introducing devices are fixed to about 0°.FIG. 11B shows an electric field distribution when the input phases of the microwaves inputted to the three outer microwave introducing devices are changed by about 180°. InFIGS. 11A and 11B , electric field intensity is indicated by different colors (black and white). InFIG. 11A , bright circular ring-shaped portions indicate portions where the electric field intensity is high around the microwave introducing devices of the antenna modules. These portions correspond to antinodes of the standing wave. Further, among these portions, darker portions represent higher electric field intensity. Furthermore, portions between the adjacent microwave introducing devices show lower electric field intensity. These portions correspond to nodes of the standing wave. Specifically, portions surrounded by a dashed line inFIG. 11A correspond to the nodes of the standing wave. Further, by changing the input phases of the microwaves inputted to the three microwave introducing devices by about 180°, the electric field intensity changes greatly, as shown inFIG. 11B . The portions, surrounded by the dashed line inFIG. 11A , correspond to the nodes of the standing wave. However, these portions are changed to the antinodes of the standing wave inFIG. 11B since the electric field intensity has been increased by changing the input phase of the microwave inputted to one of two adjacent microwave introducing devices by about 180°. That is, when the input phases of the microwaves inputted to all themicrowave introducing devices 43 are fixed to about 0°, portions between adjacentmicrowave introducing devices 43 correspond the nodes of the standing wave. However, by changing the input phases of the microwaves inputted to the three outermicrowave introducing devices 43 by about 180°, these portions are changed to correspond the antinodes of the standing wave. Based on this analysis, it can be understood that by varying the input phases periodically, the positions of the nodes and the antinodes of the standing wave can be continuously changed and electric field intensity can be uniformized. As a result, plasma density obtained by the electric field can also be uniformized. - In accordance with the present embodiment, among the multiple number of
microwave introducing devices 43, the input phase of the microwave inputted to one of two adjacent microwave introducing devices is fixed, while varying the input phase of the microwave inputted to the other microwave introducing device according to the periodic waveform such as a sine waveform. Alternatively, the input phases of the microwaves inputted to both of the two adjacentmicrowave introducing devices 43 may be varied according to periodic waveforms not overlapped with each other. However, all of the microwave introducing devices need not satisfy these conditions. By way of example, among sets of two adjacentmicrowave introducing devices 43, only a part of these sets may satisfy these conditions. - Now, a second embodiment of the present disclosure will be described.
- Although basic configurations of a microwave plasma source and a plasma processing apparatus in accordance with the second embodiment are the same as those of the first embodiment, a ceiling plate has a different configuration.
-
FIG. 12 illustrates a plane view schematically illustrating a ceiling plate and a microwave introducing device of a microwave plasma source in accordance with the second embodiment.FIG. 13 is a cross sectional view taken along a line CC′ ofFIG. 12 . As shown inFIGS. 12 and 13 , acircular ceiling plate 110 in accordance with the second embodiment includesdielectric members 110 b fitted to positions where a multiple number ofmicrowave introducing devices 43 for radiating microwaves into thechamber 1 are provided. Eachdielectric member 110 b is made of a dielectric material such as quartz and has a hexagon shape. Adjacentdielectric members 110 b are placed close to each other such that one side of a hexagon faces to one side of other hexagon. Ametal frame 110 a supporting thedielectric members 110 b has a honeycomb structure. Portions of themetal frame 110 a between the adjacentdielectric members 110 b have narrow straight lines shapes. Theframe 110 a has supportingmembers 110 c for supporting thedielectric members 110 b. - The
ceiling plate 110 serves to transmit the microwaves as stated above. In order to transmit the microwave efficiently, theentire ceiling plate 110 may be made of a dielectric material. However, when the microwaves are radiated from the multiple number ofmicrowave introducing devices 43 as in the microwave plasma source in accordance with the present embodiment, if theentire ceiling plate 110 is made of the dielectric material such as quartz, all the microwaves radiated from a certainmicrowave introducing device 43 may not be introduced into thechamber 1 but a part of the microwaves may reach anothermicrowave introducing device 43 through theceiling plate 110. In such a case, the microwave radiated from the certainmicrowave introducing device 43 and the microwave radiated from the anothermicrowave introducing device 43 may interfere with each other. Further, if theentire ceiling plate 110 is made of the dielectric material, there may also be various other problems. By way of example, a mode jump of plasma may occur easily or strength of a dielectric member may become decreased. - For these reasons, in the
ceiling plate 110 in accordance with the first embodiment, the dielectric members are provided only at positions where themicrowave introducing devices 43 of theantenna modules 41 are placed, and other portions of theceiling plate 110 have the metal frame for supporting the dielectric members. Each dielectric member may have a circular shape as in the first embodiment or may have a rectangular shape or a square shape. - If the dielectric members have circular shapes, however, the area of metal frame between the adjacent dielectric members would be increased and, thus, area occupied by the dielectric members may be reduced. In such a case, a microwave radiation area may also be reduced, making it difficult to generate plasma efficiently. Furthermore, when the dielectric members have rectangular shapes or square shapes, strength of the
ceiling plate 110 may be decreased. - In contrast, as in the second embodiment, by forming the
frame 110 a of theceiling plate 110 to have the honeycomb structure and thedielectric members 110 b to have the hexagon shapes, the area of theceiling plate 110 occupied by thedielectric members 110 b can be increased. Thus, the microwave radiation area can be increased and the plasma can be generated efficiently. Furthermore, by forming theframe 110 a to have the honeycomb structure, the strength of theceiling plate 110 can be increased. - Although the
frame 110 a is described inFIG. 12 to have the honeycomb structure, theframe 110 a may not have a perfect honeycomb structure but it may have a structure similar to the honeycomb structure. By way of example, as illustrated inFIG. 14 , outer peripheries of thedielectric members 110 b corresponding to outermicrowave introducing devices 43 may be protruded outward. In such a configuration, the areas of thedielectric members 110 b can be more increased. As described above, in accordance with the second embodiment, theframe 110 a may have a honeycomb structure and a honeycomb-shaped structure including a structure similar to the honeycomb structure. - As depicted in
FIG. 15 , a multiple number of gas discharge holes 112 may be formed at theframe 110 a of theceiling plate 110 so as to discharge a plasma gas such as an Ar gas, as in a shower device. In such a case, a gas flow path may be formed inside theframe 110 a of theceiling plate 110, and the plasmagas supply source 27 may be connected to the gas flow path via, e.g., thepipe 28. In this configuration, the plasma gas such as the Ar gas may be uniformly discharged from the gas discharge holes 112. Accordingly, the Ar gas can be excited into plasma promptly, so that uniform plasma can be generated. - Moreover, the effects of the second embodiment can be more enhanced when the second embodiment is combined with the first embodiment. However, the aforementioned effects of the second embodiment can be achieved even if the first embodiment is not combined.
- Further, the present disclosure may not be limited to the above-described embodiment and can be modified in various ways. By way of example, the circuit configuration of the microwave output unit, or the circuit configuration of the microwave supply unit and the main amplifier may not be limited to the above-described embodiments. In addition, the microwave introducing device may also not be limited to those described in the embodiments. The microwave introducing device may have various configurations as long as it can radiate a microwave appropriately. Moreover, the number or the arrangement of the microwave introducing devices may not be limited to the above embodiments.
- Further, in the above-described embodiments, the etching apparatus is used as the plasma processing apparatus. However, the present disclosure is not limited thereto and may be applicable to various other plasma processes such as a film forming process, an oxynitriding process, an asking process or the like. Furthermore, the processing target substrate is not limited to the semiconductor wafer, and various other types of substrates such as a FPD (Flat Panel Display) represented by an LCD (Liquid Crystal Display) and a ceramic substrate may be adopted.
Claims (5)
1. A microwave plasma source for introducing microwave into a processing chamber capable of performing a plasma process by exciting a gas supplied into the processing chamber into plasma by the microwave, the microwave plasma source comprising:
a microwave generator for generating microwave; and
a microwave supply unit, configured to supply the generated microwave into the processing chamber, including:
a plurality of microwave introducing devices, each introducing the microwave into the processing chamber; and
a plurality of phase controllers for adjusting phases of the microwaves input to the plurality of microwave introducing devices,
wherein the phases of the microwaves are adjusted by fixing an input phase of the microwave input to one of two adjacent microwave introducing devices while varying an input phase of the microwave input to the other microwave introducing device according to a periodic waveform, or by varying input phases of the microwaves input to both of the two adjacent microwave introducing devices according to periodic waveforms not overlapped with each other.
2. The microwave plasma source of claim 1 , wherein the periodic waveform is one of a sine waveform, a triangular waveform, a trapezoidal waveform and a waveform similar to a sine waveform.
3. The microwave plasma source of claim 1 , further comprising:
a ceiling plate serving as a top wall of the processing chamber and configured to transmit the microwaves radiated from the plurality of microwave introducing devices,
wherein the ceiling plate includes:
a plurality of dielectric members provided at positions corresponding to the plurality of microwave introducing devices; and
a metal frame, having a honeycomb structure, for supporting the dielectric members.
4. The microwave plasma source of claim 3 ,
wherein the frame has a gas flow path and a plurality of gas discharge holes, and
a gas used for the plasma process is discharged into the processing chamber from the gas discharge holes.
5. A plasma processing apparatus comprising:
a processing chamber for accommodating therein a processing target substrate;
a mounting table for mounting thereon the processing target substrate within the processing chamber;
a gas supply unit for supplying a gas into the processing chamber; and
a microwave plasma source as claimed in claim 1 ,
wherein plasma is generated by microwave introduced into the processing chamber from the microwave plasma source and a process is performed on the processing target substrate by the plasma.
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JP2010234688A JP2012089334A (en) | 2010-10-19 | 2010-10-19 | Microwave plasma source and plasma processing apparatus |
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JP (1) | JP2012089334A (en) |
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TW (1) | TW201247035A (en) |
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CN112689376A (en) * | 2021-03-15 | 2021-04-20 | 四川大学 | Microwave plasma jet excitation device adopting piezoelectric material |
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CN102458032A (en) | 2012-05-16 |
TW201247035A (en) | 2012-11-16 |
JP2012089334A (en) | 2012-05-10 |
KR20120040677A (en) | 2012-04-27 |
KR101289771B1 (en) | 2013-07-26 |
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