Dial deposition and processing apparatus

• US 4,795,299 A
• Filed: 04/15/1987
• Issued: 01/03/1989
• Est. Priority Date: 04/15/1987
• Status: Expired due to Fees

• Current Assignee: Aixtron Inc. (Aixtron AG)
• Original Assignee: Genus PLC
• Inventors: Graves, Walter E., Boys, Donald R.
• Primary Examiner(s): Spar, Robert J.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/038,540
• Time in Patent Office: 629 Days
• Field of Search: 118/426, 118/500, 118/729, 118/730, 414/217, 414/221, 414/222, 414/225, 414/590, 414/744 A, 414/417, 204/298
• US Class Current: 414/217
• CPC Class Codes: H01L 21/6719 characterized by the construction of the processing chambers, e.g. modular processing chambers
• CPC Class Codes: H01L 21/67196 characterized by the construction of the transfer chamber
• CPC Class Codes: H01L 21/67745 characterized by movements or sequence of movements of transfer devices
• CPC Class Codes: H01L 21/67751 vertical transfer of a single workpiece
• CPC Class Codes: Y10S 414/138 Wafers positioned vertically within cassette
• CPC Class Codes: Y10S 414/139 including wafer charging or discharging means for vacuum chamber
• CPC Class Codes: Y10S 414/14 Wafer cassette transporting

Abstract

A system for moving and processing workpieces includes individual stations isolated from one another and from a main chamber by seals formed by a transport mechanism. Workpieces are moved in a queue in a circular pattern, by a dial turret operated by a bell-crank and a Geneva mechanism. Stations seal to the baseplate from below, and a vacuum chamber encloses the turret assembly which operates on a post through a center hole in the baseplate. Workpieces loaded to one depended chamber are withdrawn from chambers and inserted into next chambers in a circular pattern, passing through the main chamber with each transfer, and ending back in the chamber where they were loaded. In an alternative embodiment passages between the main chamber and each individual chamber have valves allowing processing to take place without carriers attached to the turret being in the processing chambers. In another embodiment a single radial arm transfers one workpiece at a time, indexing in either direction, allowing workpieces withdrawn from one chamber to be placed in any other chamber. In other alternative embodiments automatic equipment for loading and unloading workpieces is provided with a single cassette air-lock and with in-line air locking for cassettes. Provision is made for a wide variety of processes to be performed, and processing can be from one or both sides of a workpiece.

Claims

1. A system for moving and processing workpieces comprising:

a main baseplate forming a fixed horizontal framing element of said system, having a central hole therethrough and two or more vertical passages therethrough, said vertical passages arranged at repeating angular intervals on the circumference of a circle with its center located within said central hole, said main baseplate having a substantially flat upper surface in proximity of said vertical passages;

a plurality of individual stations equal in number to the number of said vertical passages, with one of each of said stations sealed to a bottom surface of said main baseplate at each of said vertical passages, each individual station having an opening with each opening aligned with a different one of said vertical passages, one of said individual stations being an air-lock, the others being processing stations;

a vertical centerpost passing through said central hole of said main baseplate;

a turret of substantially the diameter of the locus of said vertical passages through said main baseplate, said turret fixedly attached to the center post and concentric with it;

a plurality of carrier assemblies, equal in number to the number of individual stations, said carrier assemblies configured to hold a workpiece vertically in a plane with the aid of gravity, each of said carrier assemblies attached to said turret and extending therebelow in a circular pattern congruent with the pattern of said vertical passages through said main baseplate;

means for moving said center post vertically between a lowermost position at which workpieces on said carrier assemblies are fully inserted through said vertical passages and into said individual stations, and an uppermost position at which workpieces on said carrier assemblies are fully withdrawn from said vertical passages and above the upper surface of said main baseplate;

means for indexing said center post rotationally at said upperemost position by an angular increment equal to the angular increment between said vertical passages through said main baseplate relative to said centerpost;

a sealable door opening from said one of said individual stations used as an air-lock;

a workpiece cradle attached to an inside surface of said air-lock door, said cradle being configured to hold a workpiece vertically with the aid of gravity and in the same plane as a workpiece held by one of said carrier assemblies, such that a workpiece entering said air-lock through said vertical passage will transfer from said carrier assembly to said door cradle, and a workpiece in said door cradle will transfer to said carrier assembly as said carrier leaves said air-lock through said vertical passage;

a plurality of pedestals, equal in number to the number of individual stations used as process stations, one said pedestal attached to an inner wall of each said process station, each pedestal configured to hold a workpiece substantially vertically with the aid of gravity and in substantially the same plane as a workpiece held by one of said carrier assemblies, such that a workpiece entering one of said process stations through one of said vertical passages will transfer from said carrier assembly to said process pedestal, and a workpiece on said process pedestal will transfer to said carrier assembly as said carrier leaves said process station through said vertical passage, the workpiece being supported on said pedestals during processing; and

an hermetic dome sealed to said main baseplate, said baseplate and said dome forming a main chamber enclosing said center post, turret and carrier assemblies;

said turret with said carrier assemblies being lifted, indexed and lowered by said center post moving means and indexing means, said lifting, indexing, and lowering for engaging and lifting workpieces from said door cradle and process pedestals and for transferring said workpieces through said main chamber and into the next individual chamber in the direction of indexing, the workpieces being lifted simultaneously from all said pedestals and cradles and indexed and placed simultaneously.

2. A system for moving and processing workpieces as in claim 1 wherein said carrier assemblies comprise two vertical arms spaced apart a distance greater than the width of a workpiece, and two grooved supports spaced apart less than the width of a workpiece, said grooved supports being attached one each to the lower end of each of two said vertical arms, grooves facing such that a workpiece may be supported vertically having a small edge portion engaged in the groove of each said grooved support, said workpiece then being disposed between said vertical arms.

3. A system for moving and processing workpieces as in claim 2 wherein said door cradle on said air-lock door comprises two grooved elements spaced apart less than the distance of the spacing of said two grooved supports of said carrier assemblies, such that with said door closed on said air-lock, and with a carrier assembly fully inserted onto said air-lock, a workpiece supported on said door cradle will be in a common plane with the grooves of said grooved supports of said carrier assembly, and said workpiece will be a short distance above but not touching said grooved supports of said carrier assembly.

4. A system for moving and processing workpieces as in claim 3 wherein said pedestals in said processing chambers are angled a small amount from vertical and include on each pedestal two workpiece support members at substantially the height and spacing of said support elements forming the cradle on said air-lock door, said support members angled such as to cause a workpiece transferring thereto from a lowering carrier assembly to tilt toward the angled face of said pedestal and hence to lie flat on said pedestal face.

5. A system for moving and processing workpiece as in claim 3 wherein said pedestals in said processing chambers include two workpiece support members at substantially the height and spacing of said support elements forming the cradle on said air-lock door, said support members mounted to one or more side walls or to a bottom wall of said processing chamber in a manner such that a relatively thin and flat workpiece is supported vertically by said support member, and neither face of said workpiece is occluded or shadowed, and both opposite faces of said workpiece are substantially presented for processing to opposite sides of said processing chamber.

6. A system for moving and processing workpieces as in claim 1 further comprising sealing means associated with said baseplate for effecting a seal at each said vertical passage through said baseplate as said turret assembly reaches the lowermost position, thereby sealing each process station from said main chamber and from each other process chamber.

7. A system for moving and processing workpieces as in claim 6 wherein said sealing means is an O-ring in a groove, said groove being in said main baseplate, one such groove and O-ring surrounding each said vertical passage.

8. A system for moving and processing workpieces as in claim 1 wherein said means for moving said center post vertically is a bell-crank mechanism operating on said central post from a position below said baseplate.

9. A system for moving and processing workpieces as in claim 8 wherein said means for indexing said center post rotationally comprises a Geneva wheel mechanism with a number of positions equal to the number of individual stations.

10. A system for moving and processing workpieces as in claim 9 further comprising a first sealed rotary motion feedthrough mechanism through a wall of said system for rotating said Geneva wheel.

11. A system for moving and processing workpieces as in claim 10 further comprising a second sealed rotary motion feedthrough mechanism through a wall of said system for rotating said bell-crank mechanism.

12. A system for moving and processing workpieces as in claim 1 further comprising a second baseplate spaced below said main baseplate, said stations sealed to the underside of said main baseplate being disposed above said second baseplate, said second baseplate having a pluraltiy of openings equal in number to the number of stations, each station having an opening sealed also to said openings through said second baseplate;

said system further comprising vacuum pumping means connected below said second baseplate, said vacuum pumping means for evacuating said processing stations through said openings in said second baseplate.

13. A system for moving and processing workpieces as in claim 1 wherein said main baseplate has at least one radial hole at each process station position, said radial hole intersecting said vertical passages through said main baseplate, each of said radial holes configured for mounting of one of either process gas supplies and process monitoring transducers such that process stations may be demounted without disconnecting said gas supplies and transducers.

14. A system for moving and processing workpieces as in claim 13 wherein said main baseplate also has at least one vertical hole therethrough at each process station position, said vertical holes being located toward the center of said center post from said vertical passages, and intersecting with said radial holes, said radial holes passing through said baseplate to said vertical passages;

said system further comprising pumping means connected to the main chamber for pumping the main chamber and for pumping said process chambers through said vertical holes by way of said radial holes and said vertical passages.

15. A system for moving and processing workpieces as in claim 13 wherein said main baseplate also has at least one vertical hole therethrough at each process station position, said vertical holes being located toward the center of said centerpost from said vertical passages, and intersecting with said radial holes, said radial holes passing through said baseplate to said vertical passages;

said system further comprising a plurality of pumping means, with each of said pumping means dedicated to a different one of said processing stations and connected thereto from below through said vertical holes.

16. A system for moving and processing workpieces as in claim 1 further comprising pumping means, gas supply means, monitoring means and processing means which are dedicated at each of said process stations, for performing processes in each process station independent of the processes being performed in the other process stations.

17. A system for moving and processing workpieces as in claim 16 wherein at least one of said process stations comprises chemical vapor deposition apparatus and at least one of said process stations comprises sputtering apparatus.

18. A system for moving and processing workpieces as in claim 1 wherein said carrier assemblies include means for lateral movement such that workpieces may be placed upon said pedestals and said carrier assemblies may be withdrawn;

said system further comprising sealing means activated by independently operated vacuum valves located at each of said vertical passages through said main baseplate serving each said processing station, so that processing can be performed with said carrier assemblies in said main chamber.

19. A system for moving and processing workpieces as in claim 18 wherein said turret consists of a single radial arm from said center post, said radial arm having a single carrier assembly, said means for indexing said center post indexable in either radial direction, providing for transferring workpieces optionally from any one station to any other station as desired for process sequence, said carrier residing in said main chamber during processing.

20. A system for moving and processing workpieces as in claim 18 further comprising means for automatically loading workpieces from a cassette of workpieces to said door cradle and automatically unloading processed workpieces from said door cradle back to said cassette.

21. A system for moving and processing workpieces as in claim 20 wherein said loading and unloading means is enclosed in a vacuum chamber, said chamber having opening means for placing said cassettes into and for withdrawing said cassette of workpieces from said vacuum chamber;

said system further comprising rough pumping means and high vacuum pumping means for creating a first vacuum level and a second vacuum level, respectively, in said system.

22. A system for moving and processing workpieces as in claim 21 wherein said opening means comprises two openings;

said system further comprising two vacuum gate valves with one of each of said gate valves sealed to each of said openings;

said system further comprising two cassette lock chambers with one of each of said lock chambers sealed to each of said vacuum gate valves, each lock chamber connected to said rough pumping means;

said system further comprising venting means for venting said lock chambers;

said opening means further comprising an opening for passing a cassette of wafer in or out while such chamber is vented;

said load and unload means also including means for transporting cassettes from chamber to chamber through said gate valves when said gate valves are open, one of said locks being used as an entrance lock for cassettes and the other being used as an exit lock for cassettes, so that the system can be continuously loaded and unloaded, and processing can be carrier out while air locking cassettes in and out.

23. A system for moving and processing workpieces as in claim 18 including means for automatically loading workpieces from a cassette of workpieces to said door cradle and automatically unloading processed workpieces from said door cradle back to said cassette.

24. A system for moving and processing workpieces as in claim 18 wherein said loading and unloading means is enclosed in a vacuum chamber, said chamber having an opening for placing and withdrawing cassettes of workpieces, rough pumping means and high vacuum pumping means.

25. A system for moving and processing workpieces as in claim 18 wherein said vacuum chamber enclosing load and unload means has an opening at each end, a vacuum gate valve is sealed to each said opening, and a cassette lock chamber is sealed to each said gate valve, each lock chamber having rough pumping means and venting means, and an opening for passing a cassette of wafers in or out while such chamber is vented, said load and unload means also including means for transporting cassettes from chamber to chamber, through said gate valves when open, one of said locks being used as an entrance lock for cassettes and the other as an exit lock for cassettes, providing ability to continuously load, unload and process while air locking cassettes in and out.

26. A system for moving and processing workpieces as in claim 1 further comprising means for automatically loading workpieces from a cassette of workpieces to said door cradle and automatically unloading processed workpieces from said door cradle back to said cassette.

27. A system for moving and processing workpieces as in claim 26 further comprising a vacuum chamber with said loading and unloading means enclosed therein, said vacuum chamber having opening means or placing and withdrawing cassettes of workpieces from said vacuum chamber;

said system further comprising rough pumping means and high vacuum pumping means for creating a first vacuum level and a second vacuum level respectively, in said system.

28. A system for moving and processing workpieces as in claim 27 wherein said opening means comprises two openings;

said system further comprising two vacuum gate valves with one of each of said gate valves sealed to each of said openings;

said system further comprising two cassette lock chambers with one of each of said lock chambers sealed to each of said vacuum gate valves, each lock chamber connected to said rough pumping means;

said system further comprising venting means for venting said lock chambers;

said opening means further comprising an opening for passing a cassette of wafers in or out while such chamber is vented;

said load and unload means also including means for transporting cassettes from chamber to chamber through said gate valves when said gate valves are open, one of said locks being used as an entrance lock for cassettes and the other being used as an exit lock for cassettes, so that the system can be continuously loaded and unloaded, and processing can be carried out while air locking cassettes in and out.

29. A system for moving and processing workpieces comprising:

baseplate means for providing a fixed horizontal framing element for said system, said baseplate means having a central hole therethrough and a plurality of vertical passages therethrough, said vertical passages arranged at repeating angular intervals on the circumference of a circle having its center located with said hole, said baseplate means having a substantially flat upper surface in proximity of said vertical passages and a bottom surface;

a plurality of individual stations equal in number to the number of said vertical passages, with one of each of said stations sealed to said bottom surface of said baseplate means at each of said vertical passages, each individual station having an opening for receiving a workpiece which is aligned with its respective vertical passage;

a vertical center post passing through said central hole of said baseplate means and extending above said upper surface, said center post having its center at the center of the circle defined by said vertical passages;

turret means fixedly attached to said center post and rotatable therewith, for holding at least one workiece at a radial distance from the center of said center post that is equal to the radius of the circle defined by said vertical passages;

a dome hermetically sealed to said baseplate means, said dome and said baseplate means forming a main pressure vessel enclosing the center post and turret means;

elevator means for moving said center post and turret means vertically between a lowermost position at which said workpiece would be fully inserted through any one of said vertical passages and into a corresponding one of said individual stations and an uppermost position at which said workpiece would be fully withdrawn from any one of said vertical passages and out of said corresponding individual station;

indexing means for rotating said center post and turret means through angular increments which are multiples of the angular increment between said vertical passages relative to said centerpost;

pump means for controlling the pressure inside said pressure vessel and inside said stations.

30. A system as in claim 29 wherein said turret means comprises a frame for attaching said turret means to said center post and a plurality of carrier assemblies attached to said frame and depending therefrom, each of said carrier assemblies configured for holding a workpiece having a substantially planar shape in a substantially vertical orientation at said radial distance from said center post, said carrier assemblies having an angular increment therebetween relative to said center post that is equal to the angular increment between stations.

31. A system for moving and processsing workpieces as in claim 29 further comprising processing means at said individual stations for performing processes in any one of said individual stations independent of processes performed in other of said individual stations.

32. A system for moving and processing workpieces as in claim 31 wherein at least one of said individual stations comprises chemical vapor deposition apparatus and at least one of said individual stations comprises sputtering apparatus.

33. A system for moving and processing workpieces as in claim 29 wherein said turret means further comprises transfer means for placing and retreiving said at least one workpiece in and from said individual stations, and individually operated sealing means at each of said vertical passages, such that a workpiece may be placed into or retrieved from any one of said individual stations with said sealing means open, and a workpiece may reside in an individual station with said turret assembly in said main chamber and said individually operated sealing means sealed.