Work-piece processing system

• US 7,246,985 B2
• Filed: 04/16/2004
• Issued: 07/24/2007
• Est. Priority Date: 04/16/2004
• Status: Active Grant

• Current Assignee: Axcelis Technologies Incorporated
• Original Assignee: Axcelis Technologies Incorporated
• Inventors: Ferrara, Joseph
• Primary Examiner(s): Mackey; Patrick
• Assistant Examiner(s): GREENHUT, CHARLES N
• Application Number:
  US10/826,419
• Publication Number:
  US 20050232727A1
• Time in Patent Office: 1,194 Days
• Field of Search: 414/217, 414/939
• US Class Current: 414/217
• CPC Class Codes: H01L 21/67201 characterized by the construction of the load-lock chamber
• CPC Class Codes: H01L 21/67213 comprising at least one ion or electron beam chamber coating by ion implantation C23C; ion or electron beam tubes H01J37/00
• CPC Class Codes: H01L 21/67742 Mechanical parts of transfer devices robots in general in B25J
• CPC Class Codes: H01L 21/67745 characterized by movements or sequence of movements of transfer devices
• CPC Class Codes: H01L 21/67748 horizontal transfer of a single workpiece
• CPC Class Codes: H01L 21/67778 involving loading and unloading of wafers
• CPC Class Codes: Y10S 414/139 including wafer charging or discharging means for vacuum chamber

Abstract

A transfer system for use with a tool for processing a work-piece at low or vacuum pressure such as an ion implanter for implanting silicon wafers. An enclosure defines a low pressure region for processing of work-pieces placed at a work-piece processing station within the low pressure region. A two tier multiple work-piece isolation load lock transfers work-pieces from a higher pressure region to the lower pressure for processing and back to said higher pressure subsequent to said processing. A first robot transfers work-pieces within the low pressure region from the load locks to a processing station within the low pressure region. Multiple other robots positioned outside the low pressure region transfers work-pieces to and from the two tier work-piece isolation load locks from a source of said work-pieces prior to processing and to a destination of said work-pieces after said processing.

Claims

1. For use with a tool for processing a work-piece at low pressure, a work-piece transfer system comprising:

a) a first isolation load lock housed within a load lock housing for transferring a work-piece from a higher pressure region to a lower pressure region and back to said higher pressure region including first and second access openings facing said higher pressure region at different angles to allow the first load lock to be accessed from two different directions;

b) a second isolation load lock housed within said load lock housing positioned next to the first work-piece isolation load lock for transferring a work-piece from a higher pressure region to a lower pressure region and back to said higher pressure region including first and second access openings facing said higher pressure region at different angles to allow the second load lock to be accessed from two different directions;

c) a work-piece processing station for processing work-pieces at low pressure;

d) a first robot for transferring work-pieces from one of said first and second work-piece isolation load locks to the work-piece processing station; and

e) multiple other robots positioned in said higher pressure region outside the low pressure region for transferring work-pieces to and from the adjacent work-piece isolation load locks from a source of said work-pieces prior to processing and to a destination of said work-pieces after said processing wherein each of said multiple other robots is aligned in facing relation for moving workpieces through a specified one of said first and second access openings of a given load lock.

2. The transfer system of claim 1 additionally comprising a work-piece aligner for controlling an alignment of work-pieces moved through the first and second work-piece isolation load locks.

3. The transfer system of claim 1 wherein each said load lock includes a support for supporting a work-piece placed on the support within the load lock;

and

a control valve for selectively venting a load lock to atmosphere and to a vacuum source for lowering the pressure within the load lock.

4. The transfer system of claim 1 wherein the first and second isolation load locks are spaced vertically from each other and wherein the first robot includes two spaced apart end effectors that can be moved into the first and second isolation load locks to obtain a work-piece.

5. The transfer system of claim 4 wherein the spaced apart end effectors can be raised and lowered in relation to the load locks to allow either end effector to move into either of said first or second load locks.

6. For use with a tool for processing a work-piece at low pressure, transfer apparatus comprising:

a) an enclosure defining a low pressure region for processing of work-pieces at a work-piece processing station within the low pressure region;

b) two adjacent work-piece isolation load locks wherein each load lock includes;

i) first and second access openings for selectively communicating atmospheric pressure to a load lock interior for transferring work-pieces to and from a region of atmospheric pressure wherein said two access openings confront said region of atmospheric pressure at different angles, and

ii) a third access opening for transferring work-pieces within the load lock interior to lower pressure for processing and back to said higher pressure subsequent to said processing;

c) a first robot for transferring work-pieces from the adjacent work-piece isolation load locks to a processing station within the low pressure region; and

d) multiple other robots positioned in said atmospheric region outside the low pressure region for transferring work-pieces to and from the adjacent work-piece isolation load locks from a source of said work-pieces prior to processing and to a destination of said work-pieces after said processing wherein each of said multiple other robots is aligned in facing relation for moving workpieces through a specified one of said first and second access openings of a given load lock.

7. The transfer apparatus of claim 6 wherein the adjacent work-piece isolation load locks are positioned one on top of the other.

8. The transfer apparatus of claim 7 wherein the first and second access openings of a load lock open to allow work-pieces to be inserted along different travel paths and placed on a load lock support.

9. The transfer apparatus of claim 6 wherein the first robot moves the work-pieces in an arc to a transfer station.

10. The transfer apparatus of claim 9 wherein the first robot has two end effectors, wherein each end effector can actively grasp a work-piece in either load lock.

11. The transfer apparatus of claim 10 wherein the load locks are positioned one on top of the other and the work-pieces are generally flat wafers and further wherein the two end effectors move up and down along a direction transverse to a plane of the generally flat wafers.

12. The transfer apparatus of claim 11 wherein the two end effectors are coupled to a movable carriage that moves the two end effectors simultaneously.

13. A process for serially processing multiple work-pieces at low pressure comprising:

positioning two load locks adjacent to each other wherein each load lock has first and second atmosphere access openings that confront a region of atmosphere at different angles;

providing a low pressure robot having two end effectors for moving work-pieces to a processing station from the two load locks;

positioning multiple in-air robots in facing relationship with a specified atmosphere access opening of the two load locks for moving workpieces into and out of said two load locks;

grasping an unprocessed work-piece with one in-air robot and moving said unprocessed work-piece into a first load lock of said two load locks through a first atmospheric load lock access opening having a facing relationship with said one in-air robot and placing the unprocessed work-piece inside the first load lock;

lowering the pressure within the first load lock;

removing the unprocessed work-piece from the first load lock with one end effector of said low pressure robot and moving the unprocessed work-piece to a processing station;

placing an already processed work-piece obtained from the processing station with a second end effector of said low pressure robot into one load lock of said two load locks;

raising the pressure within the one load lock; and

removing the processed work-piece from the one load lock through a specified atmospheric load lock access opening.

14. The process of claim 13 wherein a processed work-piece is placed into the one load lock at the same time an unprocessed work-piece is being processed at the processing station.

15. The process of claim 14 wherein the work-piece is a semiconductor wafer and wherein the low pressure robot delivers the wafer for placement onto a wafer chuck that attracts the wafer and further comprising reorienting the wafer and chuck prior to processing.

16. The process of claim 13 comprising positioning the two locks, one above the other.

17. The process of claim 16 comprising moving the two end effectors of the low pressure robot up and down to enable either end effector to access work-pieces within either the two load locks.

18. The process of claim 17 wherein the two end effectors are mounted collinearly to each other on a carriage that supports a drive motor for independently activating each end effector and further comprising moving the carriage up and down with respect to the two load locks to appropriately position an end effector with respect to a load lock.

19. The process of claim 13 wherein the work-piece is a generally planar wafer and additionally comprising aligning an orientation of the wafer prior to inserting an unprocessed wafer into the first load lock.

20. The process of claim 19 additionally comprising gathering an unprocessed wafer from a source of wafers with a first in-air robot, placing the unprocessed wafer onto an aligner for orientation and wherein a second in air robot removes an aligned wafer from the aligner for transfer through the first load lock to the processing station.

21. The process of claim 13 wherein one or more additional unprocessed work pieces are moved sequentially from a source by an in air robot to the first load lock prior to removal of the processed work piece from the one load lock.

22. The process of claim 21 wherein alternate ones of the additional unprocessed work pieces are placed into alternate load locks of said two load locks to allow a predecessor work piece to be removed from a pumped down load lock while an alternate load lock is opened to atmosphere for receipt of an unprocessed work piece.

23. The process of claim 13 wherein a given work piece is removed after processing from the same load lock into which said given work piece was placed prior to processing.