WO1987003979A1

WO1987003979A1 - Intelligent wafer carrier

Info

Publication number: WO1987003979A1
Application number: PCT/US1985/002574
Authority: WO
Inventors: George Allan Maney; Anthony Charles Bonora; Mihir Parikh
Original assignee: Asyst Technologies
Priority date: 1985-12-23
Filing date: 1985-12-23
Publication date: 1987-07-02
Also published as: JPH071784B2; JPS63503260A

Abstract

System mounted with a transportable container (10) for carrying articles such as semiconductor wafers which comprises a non-volatile memory (40) used to store the identity, status, and history of the articles in the container. Further, the system includes means (50) for transmitting data from the memory to an information processor (20) associated with a processing station (100) which processes the articles in a carrier (31). In a preferred embodiment, the system includes data processing capability and both receive data from and transmits data to the processing station.

Description

INTELLIGENT WAFER CARRIER

Field of the Invention

The present invention relates to standardized mechanical interface systems for reducing particle contamination of semiconductor wafers during semiconductor processing. More particularly, the present invention relates to an apparatus for information processing in standard mechanical interface systems.

Background of the Invention

A standardized mechanical interface (SMIF) system has been proposed to reduce particle contamination by significantly reducing particle fluxes onto wafers. This end is accomplished by mechanically insuring that during transport, storage and processing of the wafers, the gaseous media (such as air or nitrogen) surrounding the wafers is essentially stationary relative to the wafers and by insuring that particles from the outside environment do not enter the immediate internal wafer environment.

The SMIF concept is based on the realization that a small volume of still, particle free air, with no internal source of particles, is the cleanest possible environment for wafers. Further details of one proposed system are described in the article "SMIF: A Technology for Wafer Cassette Transfer and VLSI Manufacturing , by Mihir Parikh and ϋlrich Kaemph, Solid State Technology, July 1984, pp. 111-115, and the above cross-referenced applications.

The proposed SMIF system has three main components, namely, (1) minimum volume, dust proof transportable containers or boxes are used for storing and transporting wafer cassettes; (2) canopies are placed over the cassette ports of processing equipment so that the environments inside the boxes and the canopies become miniature clean spaces; and (3) doors on the boxes are designed to mate with doors on the interface ports on the equipment canopies and two doors are open simultaneously so that particles which may have been on the external door surfaces are trapped (sandwiched) between the doors.

In the proposed SMIF system, a box is placed at the interface port on top of the canopy at a desired processing station; latches release the boxed door and the interface port door simultaneously. A mechanical elevator lowers the two doors with the cassette riding on top into the canopy covered space. A manipulator picks up the cassette and places into the cassette port/elevator of the equipment. After processing, the reverse operation takes place.

In typical processing environments today, "clean rooms" are established in which through filtering and other techniques attempts are made to remove particles which may cause contamination on semiconductor wafer surfaces. The SMIF concept is one way which has come under consideration for improving the processing environment over that available in clean rooms.

The proposed SMIF systems involve transporting cassettes of wafers from processing station to processing station inside the boxes. A given processing station may be located long distances from the preceding station. Further, the processing may be complex, involving a large number of steps different processing times, requiring the boxes including wafer cassettes to be stored between processing stations. Thus there is a need to identify the boxes containing wafers so that information about the wafers within the boxes can be processed.

The proposed SMIF systems, however, have not been fully satisfactory. The SMIF systems which have been proposed include boxes which may be marked with "OCR" or bar codes. This sort of proposed marking will identify the particular box, however, the user is unable to effectively include information with the box concerning the wafers within the box. Accordingly, there is a need for improved apparatus for information processing in SMIF systems. Summary of the Invention

The present invention is a apparatus for transporting articles such as semiconductor wafers, to be processed from one processing station to another. The apparatus includes a transportable container for the articles. A storage means is mounted on the transportable container for storing machine readable data. On the processing station, there is a means for engaging the transportable container so that the articles within the container can be withdrawn from the container into the processing environment. Adjacent the engaging means, a communicating means for reading the machine readable data from the storage means or transportable container is mounted.

In another aspect, the apparatus of the present invention includes a data processing means for processing data mounted on the transportable container. Further, a means for transmitting data from the processing station is added for communication with the data processing means on the transportable container. In this embodiment, a means for receiving data on the transportable container is included.

The invention also provides a power supply mounted with the transportable container. The power supply may include a battery or a transformer coupled circuit which receives power from a transformer mounted adjacent the engaging means, or a combination of both.

A keyboard and a display are included in one aspect of the invention with the transportable container or on the processing station so that an operator can communicate with the apparatus. Also, the transportable container may include sensors for indicating conditions, such as engagement or disengagement of the container with the engaging means, whether a cassette of wafers is within the container or not, whether the container is in its opened or closed condition, and other conditions which may be relevant to the particular processing sequence being conducted. Brief Description of the Drawings

Fig. 1 shows a perspective view of a SMIF system positioned adjacent processing equipment.

Fig. 2 is a schematic representation of a SMIF system employing the present invention.

Fig. 3A and 3B are circuit diagrams of one embodiment of the present invention.

Fig. 4 is an alternative embodiment of an apparatus according to the present invention.

Fig. 5 is a schematic diagram of a power supply according to the present invention.

Fig. 6 is a schematic representation of the mounting relationship of apparatus according to the present invention.

Fig. 7 is a block diagram of a system included on the transportable container in one embodiment of the present invention.

Fig. 8 is a chart used in explanation of part of the circuit of Fig. 5.

Detailed Description

With reference to the drawings, a detailed description of the present invention is provided.

In Fig. 1, a semiconductor wafer processing station 100 is shown. A given semiconductor manufacturing process may include any number of processing stations such as the station 100 shown in Fig. 1. The stations are manufactured to handle processing steps such as the application of photo resist materials, the alignment of masks for exposing photo resist materials, the deposition of materials on semiconductor wafers, and so forth.

Fig. 1 shows a transportable container 10 for semiconductor wafers, or other articles to be processed, mounted on the processing station 100. The transportable container 10 is removeably engaged on the canopy 30 of the processing station 100 by a means 60 for engaging described with reference to Fig. 2. The transportable container 10 is adapted for containing a cartridge 31 for holding a plurality of semiconductor wafers 32. The cartridge 31 is lowered into the processing station 100 without exposure to outside air.

According to the present invention, an intelligent data card 40 is mounted on the transportable container 10. The term "data card" as used herein refers to the portion of the present invention mounted on the transportable container 10, and at a minimum includes data storage means as described below. Further, mounted on the processing station 100 is a means 50 for communication with an electronic card 40 on a transportable container 10 engaged on the processing station 100. The means 50 for communicating with the data card 40 is connected to a data processor 20 on the processing station 100. The data processor 20 may include a display 21 such as an LED or liquid crystal display. Also, the data processor 20 may include a keyboard 22 for inputting data regarding for instance the control of the process.

In operation, an operator will carrier the transportable container 10 from processing station 100 to processing station with the data card 40 attached to the container 10. The data stored in the data card 40 is communicated to the means 50 on the processing station 100 for communicating with the data card 40 when the transportable container 10 is engaged. The data from the data card 40 on the transportable container 10 is communicated through the means 50 to the data processor 20. In preferred embodiments as described below in more detail, the data processor 20 may also communicate to the data card 40 through the means 50.

Fig. 2 illustrates schematically the transportable container 10 engaged on the canopy 30 of a processing station. An engaging means 60 for engaging the transportable container 10 on the canopy 30 of the processing station is shown. The engaging means 60 includes a guide 61 on the canopy. Also, a tab 62 is formed on the transportable container 10. When the transportable container 10 is mounted on the guide 61 and fully engaged, the port 70 on the canopy 30 through which the cartridge of semiconductor wafers is lowered, is aligned with the transportable container 10. The data card 40 is mounted on the transportable container 10 along at least one side of the transportable container 10. The communicating means 50 is mounted adjacent the engaging means 60 in relationship with the card 40. The communicating means 50 is connected over communicating line

51 to the process controller 20 on the processing station 100.

Fig. 3A illustrates a circuit for mounting on the data card 40 in one embodiment of the present invention. Fig. 3B illustrates a communication means 50 for receiving data from the card 40 as shown in Fig. 3A. The circuit of Fig. 3A includes a timer/counter 41 and a storage means 42 such as a "PROM" or other stable storage device. The timer/counter 41 is connected to the storage means 42 across a communication bus 43. The timer/counter, when power is applied, generates addresses in sequence to the storage means 41 which outputs data through the light emitting diode 44 or other optical transmission means. In the embodiment of Fig. 3A, there is a single light emitting diode mounted on the data card 40. In this manner the timer/counter sequences through data locations in the storage means 41 and causes data to be output serially through the light emitting diode 44.

The communicating means 50 of Fig. 3B includes a photosensitive transistor 52 or other photo detector which responds to the data transmitted by the light emitting diode 44 to generate a signal across the control line 51 for communication with process control on the processing station 100. When the transportable container 10 is engaged on the engaging means 60 as shown in Fig. 2, the light emitting diode 44 and the photosensitive transistor

52 are aligned for optimum communication. The data card 40 includes a power supply 45, such as a battery. The power supply will be applied to the timer/counter by a switch 46 which is engaged only when the transportable container 10 is fully engaged on the engaging means 60.

An alternative embodiment for a circuit on the data card 40 is shown in Fig. 4. The embodiment of Fig. 4 includes a microcomputer 101 or other data processing means and a static memory device such as a RAM 102. The microcomputer 101 communicates with the memory device 102 across the bus 103. The microcomputer 101 communicates with a transmitter 104 such as the light emitting diode 105. Also, the microcomputer 101 communicates with a receiver 106 such as the photosensitive transistor 107. The microcomputer receives power from power supply (described below) at +5 volts along line 108. The memory device 102 receives power from a battery along line 109. The storage device 102 likewise receives an enable signal on line 110 when the power supply supplying power to the microcomputer 101 is in operation.

The generation of the power supply, voltage on line 108, the battery voltage on line 109 and the enable signal on line 110 is accomplished by the circuit shown in Fig. 5.

Fig. 5 shows a power supply 120 for mounting on the data card 40 used in conjunction with the circuit shown in Fig. 4. The power supply 120 is adapted to receive power through a transformer coupling device 121, when the transportable container 10 is engaged by the engaging means 60 on the processing station 100. The relationship of the transformer coupling is described in more detail with reference to Fig. 6. An AC signal is received from transformer coupling means 121 and converted to DC in an AD to DC converter 122, such as the bridge shown in Fig. 5. A voltage regulator 123 may be included to provide a stable voltage for the operation of the components on the data card 40. The output of the voltage regulator 123 is supplied as the power supply voltage to the microcomputer 101 across line 108 in the embodiment of Fig. 4. On the data card 40, a battery 125 is included. The battery voltage is slightly less than the output of the voltage regulator 123 on line 108. It is connected through the Shottley diode 126 to the node 127 which is likewise connect through a Shottley diode 128 to the power supply output on line 108. Node 127 is supplied as the battery voltage to the storage device 102 on line 109.

The memory enable signal (MENABLE) operates to enable the memory device 102 only when the power from the transformer coupled power 121 is turned on. For the embodiment shown in Fig. 5 including the rectifying optocoupler 141 and the circuit including Rl and Cl and the diode 142, the memory enable circuit is generated as it will be described with reference to Fig. 8.

The rectifying optocoupler 141 is a means for generating voltage on line 143 from the power supply such as battery 125 when the power from the transformer coupling device is off. When the power from the transformer coupling device turns on as indicated by line 200 of Fig. 8 at point 201, output on line 143 tends to drop which can be seen at point 301 of line 300 on Fig. 8. However, the speed at which the voltage on line 143, MENABLE can drop as determined by the time constant set by Rl and Cl. Thus, the power on line 108 will reach the voltage necessary to drive the microcomputer 101 before the enable signal on line 110 reaches a level to enable the memory device 102. This prevents causing disruption of the data stored in the memory device before the power is completely up in the data card 40.

However, when power turns off at point 202 in Fig. 8, the rectifying optocoupler 141 will supply a charging current across line 143 which will rapidly charge the capacitor Cl as can be seen at point 302 on line Fig. 8. „ Thus, the static RAM will be disabled very rapidly when power is turned off from the transformer coupling device 121. A variety of other circuits for protecting the data stored in the memory device 102 can be devised as suits the particular embodiment of the data card 40 chosen by the user.

Fig. 6 shows one configuration for mounting the data card 40, such as the one described with reference to Figs. 4 and 5, in communication with the communication means 50 for receiving the data from the data card 40 and transmitting data to the data card 40. When the transportable container 10 is fully engaged on the engaging means 60 and mounted on the canopy 30 of the processing station, the data card 40 and the communicating means 50 are aligned for communication.

As mentioned with reference to Fig. 5, a transformer coupling device 21 is mounted on the data card 40. Likewise, a mate transformer coupling device 131 is mounted on the communicating means 50. When the transportable container 10 is engaged on the engaging means 60 fully, the transformer coupling device 121 and its mate 131 are aligned so power is transmitted from the communicating means 50 to the data card 40 on the transportable container 10.

Also shown in Fig. 6 schematically are the transmitting means 104 and the receiving means 106 on the card 40. Mounted adjacent the transmitting means 104 on the communicating means 50 when the transportable container 10 is fully engaged is a mate receiving means 134 for receiving the data from the data card 40. Also a transmitting means 136 is mounted on the communicating means 50 so that it is adjacent the receiving means 106 on the transportable container 10 when the transportable container 10 is fully engaged on the engaging means 60. The communicating means 50 communicates across the communication line 51 with the data processing means 20 on the processing station 100.

A preferred embodiment of the circuit mounted on the data card 40 is shown in Fig. 7. The data card 40 shown 10

schematically in Fig. 7 includes a data processing system 151 in communication across a bus 152 with a plurality 153 of input/output devices.

The data processing system includes a CPU 154, a non-volatile memory device such as a ROM 155, a random access memory device 156 for reading and writing data, and a power supply 157 such as the power supply shown in Fig. 5.

The plurality of input/output devices include any one of the following devices. First, a display 160, such as an LED or liquid crystal display, may be mounted on the data card 40 for providing data to an operator. Also a keyboard 161 may be mounted on the data card 40 with the transportable container 10 so that an operator may control data stored within the data card 40.

A sensor device 162 may be included on the data card 40 which communicates with a plurality of sensors on the transportable container 10. These sensors may provide information regarding conditions, such as engagement or disengagement of the transportable container 10 with an engaging means 60, opening or closing of the port in the transportable container 10 for allowing access to the articles stored within a container or other conditions. Further, a sensor may be included which indicates whether a retaining device has engaged the articles stored in the container. Many other sensors may be included depending on the particular processing steps being carried out and the characteristics of articles being transported in the transportable container 10.

The plurality of input/output devices 153 includes a transmitter 163 and a receiver 164 such as the light emitting diode 44 and photosensitive transistor 52 discussed with reference to Figs. 4 and 6. The transmitter 163 and receiver 164 may be of other varieties of phototransistors and photodetectors as suited to the particular use required. Further, the transmitter and receiver may be comprised of a magnetic tape and a magnetic reading head. Other acoustic, inductive or optical means of accomplishing data communication between the electronic data card 40 and the communication means 50 may be implemented as suits the particular needs of the device.

Further, the data card 40 may include a real time clock 165 for generating data regarding real time. Data from the clock 165 may be useful by the processing stations in determining parameters for processing and the like. Also, the clock 165 may be used for determining length of storage time for the articles contained in the transportable container 10.

The foregoing description of a preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously, many modifications and variations are possible in light of the above teaching. The particular embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.

Claims

1. An apparatus for transporting articles to be processed between processing stations, comprising: transportable container for the articles to be processed and adapted for engaging at least one processing station; data storage means mounted on the transportable container for storing machine readable data; and means, mounted on the at least one processing station, for reading data from the data storage means when the transportable container is engaged on the at least one processing station.

2. The apparatus of Claim 1, further including: transmitting means mounted with the data storage means for transmitting the data.

3. The apparatus of Claim 2, further including: receiving means, mounted with the means for reading, for receiving the transmitted data.

4. The apparatus of Claim 1, further including: power supply means for supplying power for the data storage means.

5. The apparatus of Claim 4, wherein: the power supply means includes a battery.

6. The apparatus of Claim 4, wherein: the power supply means includes means for receiving power from the processing station when the transportable container is engaged on the processing station.

7. The apparatus of Claim 1, further including: optical communication means, for communicating data from the data storage means to the means for reading.

8. The apparatus of Claim 1, further including: inductive communication means for communicating data from the data storage means to the means for reading.

9. The apparatus of Claim 1, further including: acoustic communication means for communicating data from the data storage means to the means for reading.

10. An apparatus for transporting articles to be processed between processing stations, comprising: transportable container for the articles to be processed adapted for engaging at least one processing station; data processing means mounted on the trans¬ portable container, for processing and storing data; and communicating means for two way data communi¬ cation between the data processing means and the at least one processing station.

11. The apparatus of Claim 10, further including: input means, mounted on the transportable container, for inputting data to the data processing means.

12. The apparatus of Claim 10, further including: display means, mounted on the transportable container, for displaying data from the data processing means.

13. The apparatus of Claim 10, further including: sensor means, mounted in communication with the data processing means, for sensing a condition of the transportable container. U

14. The apparatus of Claim 10, wherein: the communicating means, includes means for optical transmission and reception of data.

15. The apparatus of Claim 10, wherein: the communicating means includes means for inductive transmission and reception of data.

16. The apparatus of Claim 10, wherein: the communicating means includes means for acoustic transmission and reception of data.

17. The apparatus of Claim 10, further including: power supply means for supplying power to the data processing means.

18. The apparatus of Claim 17, wherein: the power supply means includes a battery.

19. The apparatus of Claim 17, wherein: the power supply means includes means for receiving power from the processing station.

20. The apparatus of Claim 10, further including: a clock, mounted on the transportable container for generating real time data.