CHEMICAL VAPOR DEPOSITION METHODS, ATOMIC LAYER DEPOSITION METHODS, AND
VALVE ASSEMBLIES FOR USE WITH A REACTIVE PRECURSOR IN SEMICONDUCTOR PROCESSING
TECHNICAL FIELD
[0001] This invention relates to chemical vapor deposition methods, including atomic layer deposition, and to valve assemblies for use with a reactive precursor in semiconductor processing.
BACKGROUND OF THE INVENTION
[0002] Semiconductor processing in the fabrication of integrated circuitry typically includes the deposition of layers on semiconductor substrates. Exemplary processes include physical vapor deposition (PVD) and chemical vapor deposition (CVD). In the context of this document, "CVD" includes any process, whether existing or yet-to-be developed, where one or more vaporized chemicals is fed as a deposition precursor for reaction and adherence to a substrate surface. By way of example only, one such CVD process includes atomic layer deposition (ALD). With typical ALD, successive mono-atomic layers are adsorbed to a substrate and/or reacted with the outer layer on the substrate, typically by successive feeding of different precursors to the substrate surface.
[0003] Chemical vapor depositions can be conducted within chambers or reactors which retain a single substrate upon a wafer holder or susceptor. One or more precursor gasses are typically provided to a shower head within the chamber which is intended to uniformly provide the reactant gasses substantially homogeneously over the outer surface of the substrate. The precursors react or otherwise manifest in a deposition of a suitable layer atop the substrate. Plasma enhancement may or may not be utilized, and either directly within the chamber or remotely therefrom.
[0004] In certain chemical vapor deposition processes, including ALD, precursors are pulsed or otherwise intermittently injected into the reactor for reaction and/or deposition onto a substrate. In many cases, it is highly desirable to turn the individual precursor flows on and off very quickly. For example, some deposition processes utilize plasma generation of a precursor in a chamber remote from the deposition chamber. As the precursor leaves the remote plasma generation chamber, such typically converts to a short lived, non-plasma desired active state intended to be maintained for reaction in the deposition chamber. Yet plasma generation in the remote chamber is very pressure dependent, and the plasma typically ceases in the remote chamber when switching/pulsing the active species flow to the chamber. Accordingly, such process are expected to utilize pulsed remote plasma generation, and which may not be practical.
[0005] The invention was motivated in overcoming the above-described drawbacks, although it is in no way so limited. The invention is only limited by the accompanying claims as literally worded without interpretative or other limiting reference to the specification or drawings, and in accordance with the doctrine of equivalents.
SUMMARY
[0006] The invention includes chemical vapor deposition methods, including atomic layer deposition, and valve
assemblies for use with a reactive precursor in semiconductor processing. In one implementation, a chemical vapor deposition method includes positioning a semiconductor substrate within a chemical vapor deposition chamber. A first deposition precursor is fed to a remote plasma generation chamber positioned upstream of the deposition chamber, and a plasma is generated therefrom within the remote chamber and effective to form a first active deposition precursor species. The first species is flowed to the deposition chamber. During the flowing, flow of at least some of the first species is diverted from entering the deposition chamber while feeding and maintaining plasma generation of the first deposition precursor within the remote chamber. At some point, diverting is ceased while feeding and maintaining plasma generation of the first deposition precursor within the remote chamber.
[0007] In one implementation, a chemical vapor deposition method includes positioning a semiconductor substrate within a chemical vapor deposition chamber. A first deposition precursor is fed to the chamber through at least a portion of a rotatable cylindrical mass of a valve assembly. During the flowing, flow of at least some of the first deposition precursor is diverted from entering the deposition chamber by rotating the cylindrical mass in a first rotational direction. At some point while diverting is occurring, the cylindrical mass is rotated in the first rotational direction effective to cease said diverting.
[0008] In one implementation, a valve assembly for a reactive precursor to be used in semiconductor processing includes a valve body having at least one inlet and at least two outlets. The inlet is configured for connection with a reactive precursor source. A first of the outlets is configured for connection with a feed stream to a semiconductor substrate processor chamber. A second of the outlets is configured for diverting precursor flow away from said chamber. The valve body includes a first fluid passageway therein extending between the inlet and the first outlet. The valve body has a second fluid passageway extending between the first fluid passageway and the second outlet. A control plate and/or generally cylindrical mass is mounted for at least limited rotation within the body proximate the first and second passageways. Such includes an arcuate region at least a portion of which is received within the first passageway. The arcuate region includes a first region having an opening extending therethrough and which is positionable into a first selected radial orientation to provide the inlet and the first outlet in fluid communication with one another through the first passageway while restricting flow to the second passageway. The arcuate region includes a second region positionable into the first radial orientation to provide the inlet and second outlet in fluid communication through the first and second passageways while restricting flow to the first outlet.
[0009] Other aspects and implementations are contemplated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Preferred embodiments of the invention are described below with reference to the following accompanying drawings.
[0011] FIG. 1 is a diagrammatic illustration of a preferred embodiment implementation of an aspect of the invention.
[0012] FIG. 2 is a diagrammatic sectional view taken through line 2-2 in FIG. 3 of a valve assembly in accordance with an aspect of the invention, and in one operational orientation.
[0013] FIG. 3 is a sectional view taken through line 3-3 in FIG. 2.
[0014] FIG. 4 is a sectional view taken through line 4-4 in FIG. 5, and is of the FIG. 2 valve assembly in another operational orientation.
[0015] FIG. 5 is a sectional view taken through line 5-5 in FIG. 4.
[0016] FIG. 6 is a diagrammatic sectional view taken of an alternate embodiment valve assembly in accordance with an aspect of the invention, and in one operational orientation.
[0017] FIG. 7 is an enlarged sectional view taken through line 7-7 in FIG. 6.
[0018] FIG. 8 is an enlarged perspective view of a component of the FIG. 6 valve assembly.
[0019] FIG. 9 is a diagrammatic sectional view of the FIG. 6 valve assembly in another operational orientation.
[0020] FIG. 10 is an enlarged sectional view taken through line 10-10 in FIG. 9.
[0021] FIG. 11 is an enlarged diagrammatic sectional view of the FIG. 6 valve assembly in yet another operational orientation.
[0022] FIG. 12 is an enlarged diagrammatic sectional view of the FIG. 6 valve assembly in still another operational orientation.
DETAILED DESCRIPTION OF THE
PREFERRED EMBODIMENTS
[0023] This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws "to promote the progress of science and useful arts" (Article 1, Section 8).
[0024] A first embodiment chemical vapor deposition method is described initially with reference to FIG. 1. Such depicts a chemical vapor deposition chamber 12 having a semiconductor substrate 14 positioned therein. In the context of this document, the term "semiconductor substrate" or "semiconductive substrate" is defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term "substrate" refers to any supporting structure, including, but not limited to, the semiconductive substrates described above.
[0025] A remote plasma generation chamber 16 is positioned upstream of deposition chamber 12. Any existing or yet-to-be-developed remote plasma generation is contemplated. Plasma generator 16 is fed by an inlet stream 18 for feeding some suitable first deposition precursor thereto. A valve assembly 20 is depicted as being received intermediate plasma generator 16 and deposition chamber 12. An outfeed line 22 from plasma generator 16 is depicted as being
an in-feed line to valve assembly 20. An out-feed line 24 feeds from valve assembly 24 to deposition chamber 12, and another out-feed line 26 from valve assembly 20 is directed away from feeding to deposition chamber 12. More than the illustrated valve assembly input and outputs are of course contemplated.
[0026] Valve assembly out-feed line 24 includes exemplary additional in-feed lines 28 and 30. Such might be configured for providing additional deposition precursors and/or purge gasses for separate or combined flow with precursor from valve assembly 20 to deposition chamber 12. More or fewer downstream lines could be included, of course, as well as being directly provided to chamber 12 apart from stream 24.
[0027] The above-described and illustrated embodiment of FIG. 1 is but one example diagrammatic depiction usable in carrying out methodical aspects of the invention. Any other processing in accordance with the method claims as literally worded without limiting or interpretative reference to the specification or drawings is also of course contemplated.
[0028] With semiconductor substrate 14 positioned within deposition chamber 12, a first deposition precursor is fed to remote plasma generation chamber 16. A plasma is generated therefrom within the remote chamber effectively to form a first active deposition precursor species for provision to deposition chamber 12. Such first species is flowed to deposition chamber 12 via line 22, valve assembly 20 and line 24. During such flowing, the flow of at least some of the first species is diverted from entering deposition chamber 12, all while feeding and maintaining plasma generation of the first deposition precursor within the remote chamber. For example in the preferred embodiment, valve assembly 20 is operated for diverting the flow of at least some of the first species into line 26 as opposed to line 24. In the depicted preferred embodiment, diverting and ceasing thereof is controlled by a single valve assembly 20 located downstream of remote chamber 16 and upstream of deposition chamber 12 as respects flow of the first deposition precursor.
[0029] In one preferred embodiment, the diverting is effective to divert substantially all of the first species from entering the deposition chamber, and all while feeding and maintaining plasma generation of the first deposition precursor within the remote chamber. In other words in the depicted preferred embodiment, line 24 is effectively completely blocked off by valve assembly 20, with line 26 being provided in an open state by valve assembly 20.
[0030] In one preferred embodiment, the method is atomic layer deposition, with chamber 12 comprising an atomic layer deposition chamber. Flowing of the first species to chamber 12 and substrate 14 therein is thereby effective to form a first monolayer on the substrate. In one preferred atomic layer deposition while such diverting is occurring, for example into line 26, a purge gas is flowed to chamber 12, and all while feeding and maintaining plasma generation of the first deposition precursor within the remote chamber. For example in the FIG. 1 depicted embodiment, a purge gas could be flowed to chamber 12 via one or both of lines 28 and 30. Further in one preferred atomic layer deposition method in accordance with an aspect of the invention, after flowing the purge gas and while diverting, a second deposition precursor different from the first deposition precursor
is fed to deposition chamber 12 effective to form a second monolayer on the first monolayer, and all while feeding and maintaining plasma generation of the first deposition precursor within remote chamber 16. Again in the depicted exemplary embodiment, one or both of lines 28 and 30 could be utilized for the same. Further in accordance with one preferred atomic layer deposition method implementation, after forming the second monolayer and while diverting, a purge gas (the same or different from the first-described purge gas) is flowed to the chamber all while feeding and maintaining plasma generation of the first deposition precursor within remote chamber 16.
[0031] Regardless, a chemical vapor deposition method in accordance with an aspect of the invention contemplates ceasing the diverting all while feeding and maintaining plasma generation of the first deposition precursor within the remote chamber. In one embodiment where the diverting constitutes ceasing essentially all flow of the first species from entering the deposition chamber, such ceasing of the diverting will result in the resumption of first species flow to chamber 12. In one embodiment where such diverting does not constitute diversion of all of the first species from entering the deposition chamber, such ceasing of the diverting will result in an increased rate of flow of the first species to chamber 12.
[0032] In one atomic layer deposition method in accordance with an aspect of the invention, another monolayer is effectively formed on the substrate. Such monolayer may be the same as the first monolayer. Such monolayer may be a third monolayer formed on the second monolayer, which is the same as either the first or second monolayers, or some reaction product thereof.
[0033] In one considered aspect, the flowing of the first species to deposition chamber 12 can be considered as being at subatmospheric pressure, and comprises flow into a first passageway inlet, for example the inlet to line 24 exiting valve assembly 20. The diverting can be considered as comprising flow into a second passageway inlet, for example into line 26 from valve assembly 20. In accordance with one aspect of the invention, the method comprises maintaining pressure of the first inlet and the second inlet within 500 mTorr, and more preferably within 100 mTorr, from one another during the flowing and the diverting. By way of example only, maintaining such pressure control during the entirety of the deposition process can facilitate maintenance and control of plasma within remote generator 16. Yet in one preferred embodiment, the invention contemplates keeping the pressure of the first inlet and the second inlet greater than 500 mTorr from one another during the flowing and the diverting. Subatmospheric pressure within the exemplary system, as well as within plasma generator 16, is intended to be maintained in the preferred embodiment primarily by line 26 and an out-feed line 32 from chamber 12 to the same or different subatmospheric vacuum pressure sources.
[0034] In one exemplary preferred embodiment, particularly where the diverting is of all flow from entering line 24, the diverting preferably takes place over a time period sufficient to reduce the risk of temporarily isolating vacuum pressure from plasma generator 16, which might otherwise cause extinguishing of the plasma. In one preferred embodiment, the diverting takes from 0.1 second to 1.0 second from
staring the diverting of the first species to total diversion of the first species, and in another embodiment takes more than 1.0 second.
[0035] In one preferred embodiment, the diverting, for example utilizing valve assembly 20, comprises rotating a cylindrical valve mass. In one preferred embodiment, the diverting, for example utilizing valve assembly 20, comprises rotating a valve plate which may or may not constitute a cylindrical valve mass. For example, and by way of example only, such a valve plate might be square or rectangular in cross-section, as opposed to being substantially round in at least one cross-section.
[0036] In one exemplary implementation, the diverting, for example using valve assembly 20, can comprise pivoting a valve flap, and in one exemplary implementation can comprise straight linearly sliding of a diverting valve mass.
[0037] By way of example only, two exemplary valve assembly constructions usable in carrying out methodical aspects of the invention are described with reference to FIGS. 2-12. The invention also contemplates valve assemblies for use in semiconductor processing with reactive precursors independent of any method claimed or described herein. The respective method claim families and apparatus claim families stand as literally worded, without reference to the other. In other words, the concluding apparatus claims are not limited by the method claims, nor are the concluding method claims limited by any attribute of the apparatus claims, unless literal language appears in such claims, and without any limiting or interpretative reference to the specification or drawings.
[0038] An exemplary first embodiment semiconductor processing reactive precursor valve assembly is described with reference to FIGS. 2-5, and is indicated generally with reference numeral 36. FIGS. 2 and 3 depict assembly 36 in one exemplary operational configuration, while FIGS. 4 and 5 depict assembly 36 in another operational configuration. Valve assembly 36 comprises a valve body 37 having at least one inlet 38 and at least two outlets 40 and 42. Inlet 38 is configured for connection with a reactive precursor source. First depicted outlet 40 is configured for connection with a feed stream to a semiconductor substrate processor chamber, and second outlet 42 is configured for diverting precursor flow away from such chamber. Valve body 37 comprises a first fluid passageway 44 therein extending between inlet 38 and first outlet 40. Valve body 37 also comprises a second fluid passageway 46 extending between first fluid passageway 44 and second outlet 42. In the depicted preferred embodiment, first passageway 44 extends in a straight axial line through valve body 37 from inlet 38 to outlet 40, and second passageway 46 extends in a straight axial line through valve body 37 perpendicular to and from first passageway 44 to second outlet 42. Either might be of any constant or variable cross sectional shape, and/or size.
[0039] A control mass 48 is mounted for at least limited rotation within body 37 proximate the first and second passageways. In one implementation, control mass 48 is in the form of a control plate. In one implementation, control mass 48 is in the form of a generally cylindrical mass. In the depicted preferred embodiment, control mass 48 is in the form of both a control plate which is round and in the form of a generally cylindrical mass. The depicted embodiment shows control plate 48 mounted for rotation about a central
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