Wafer transfer system having rotational capability

• US 5,615,988 A
• Filed: 05/22/1996
• Issued: 04/01/1997
• Est. Priority Date: 07/07/1995
• Status: Expired due to Term

• Current Assignee: Brooks Automation Incorporated (Azenta, Inc.)
• Original Assignee: PRI Automation, Inc. (Azenta, Inc.)
• Inventors: Weiss, Mitchell, Wiesler, Mordechai
• Primary Examiner(s): Bucci, David A.
• Application Number:
  US08/651,715
• Time in Patent Office: 314 Days
• Field of Search: 414/416, 414/786, 414/937-939, 414/935, 414/217, 414/222
• US Class Current: 414/416.03
• CPC Class Codes: H01L 21/67778 involving loading and unloading of wafers
• CPC Class Codes: H01L 21/67781 Batch transfer of wafers
• CPC Class Codes: H01L 21/68707 the wafers being placed on a robot blade, or gripped by a gripper for conveyance
• CPC Class Codes: Y10S 414/137 including means for charging or discharging wafer cassette
• CPC Class Codes: Y10S 414/138 Wafers positioned vertically within cassette

Abstract

A wafer transfer system is operable with a front or side loading wafer carrier to move one or more horizontally oriented wafers out of the carrier and to rotate the wafers to a vertical orientation in which the wafers are accessible for further processing. The transfer system provides a wafer extractor which employs a plurality of paired fingers of a size and configuration to fit between the spaced, stacked wafers in the carrier for lifting the wafers off the shoulders of the carrier. The fingers are then movable generally horizontally to remove the wafers from the carrier into two angled combs having ledges for receiving wafers. The fingers and combs are rotated to a vertical orientation in which the wafers are supported along their edges by the combs. The fingers are shifted horizontally a small amount relative to the combs to disengage from the wafers, either by a translation following the rotation or by rotating the fingers and combs about different axes. In this manner, the wafers are in a position from which they can be accessed by a robot arm according to the particular process. In a further embodiment, the fingers and combs are also translated forward during the rotation, thereby minimizing the floor space or footprint required by the system.

Claims

1. A semiconductor wafer transfer system for moving a wafer horizontally into and out of a wafer support device to and from a position in which the wafer is maintained in a vertical orientation accessible for further processing, the wafer support device having opposed, paired shoulders on interior walls thereof to support the wafer in a horizontal orientation, the support device further having a vertical opening therein, the wafer transfer system comprising:

a base positioned adjacent the opening in the wafer support device;

an extraction structure mounted to the base for generally horizontal reciprocal movement into and out of the wafer support device for removing the wafer from the wafer support device along a generally horizontal path, the extraction structure further mounted to the base for rotation to a generally vertical orientation; and

a wafer support structure comprising wafer receiving elements disposed to receive the wafer from the extraction structure, the wafer support structure mounted to the base for rotation to a generally vertical orientation concurrently with the extraction structure.

2. The wafer transfer system of claim 1, wherein the wafer receiving elements each include a recess configured to receive an edge portion of the wafer.

3. The wafer transfer system of claim 1, wherein the wafer receiving elements each include a plurality of recesses configured to receive an edge portion of an associated wafer.

4. The wafer transfer system of claim 1, wherein the wafer support structure comprises two wafer receiving elements disposed at an angle with respect to each other to receive differing portions of the wafer.

5. The wafer transfer system of claim 1, wherein the extraction structure comprises a frame having an opening therethrough and the wafer support structure comprises a pair of arms extending through the opening, the wafer receiving elements being mounted to the arms to receive the wafer in a horizontal orientation from the extraction structure.

6. The wafer transfer system of claim 1, wherein the extraction structure and the wafer support structure are mounted for rotation about a single axis.

7. The wafer transfer system of claim 6, wherein the extraction structure is mounted for a horizontal shift when in the vertical orientation away from the wafer support structure to free a wafer from the extraction structure, leaving the wafer in the vertical orientation supported solely by the wafer support structure.

8. The wafer transfer system of claim 1, wherein the extraction structure and the wafer support structure are mounted for rotation about differing axes, whereby the extraction structure and the wafer support structure traverse differing arcs during rotation to the vertical orientation, whereby the wafer is freed from the extraction structure during rotation to the vertical orientation, leaving the wafer in the vertical orientation supported solely by the wafer support structure.

9. The wafer transfer system of claim 1, wherein the extraction structure and the wafer support structure are mounted for horizontal translation toward the wafer support device during rotation to the vertical orientation.

10. The wafer transfer system of claim 9, further comprising a curved track and wherein the extraction device includes a cam follower disposed to traverse the curved track during rotation to the vertical orientation.

11. The wafer transfer system of claim 1, wherein the extraction structure comprises a pair of fingers, each finger mounted to one of a pair of upstanding members to extend outwardly in a generally horizontal plane toward the opening in the support device, the fingers being spaced apart a distance to fit beneath the wafer in the wafer support device at a location inwardly of the shoulders.

12. The wafer transfer system of claim 11, further comprising a lifting mechanism for providing a component of relative vertical motion between the extraction structure and the wafer support device to bring the fingers into and out of contact with the undersurface of the wafer for lifting the wafer off and loading the wafer onto the shoulders of the support device.

13. The wafer transfer system of claim 1, wherein the extraction structure comprises a plurality of pairs of fingers, each finger of each pair mounted to one of a pair of upstanding members to extend outwardly in a generally horizontal plane toward the opening in the support device, the fingers of each pair being spaced apart a distance to fit beneath the wafer in the wafer support device inwardly of the shoulders, the pairs being vertically spaced apart a distance to fit between a plurality of wafers in the wafer support device.

14. The wafer transfer system of claim 1, further comprising a track mounted to the base, the extraction structure being mounted for reciprocal motion along the track.

15. A semiconductor wafer transfer system for moving a wafer horizontally into and out of a wafer support device to and from a position in which the wafer is maintained in a vertical orientation accessible for further processing, the wafer support device having opposed, paired shoulders on interior walls thereof to support the wafer in a horizontal orientation, the support device further having a vertical opening therein, the wafer transfer system comprising:

means for translating the wafer generally horizontally into and out of the wafer support device;

means for receiving the wafer from the translating means and for supporting the wafer in a vertical orientation; and

means for rotating the receiving means and the translating means concurrently to rotate the wafer to and from a generally vertical position in which the wafer is accessible to further processing equipment.

16. The wafer transport system of claim 15, wherein the receiving means comprise a wafer support structure comprising wafer receiving elements disposed to receive the wafer from the translating means, the wafer receiving elements each having a recess configured to receive an edge portion of the wafer.

17. The wafer transfer system of claim 16, wherein the wafer receiving elements are disposed at an angle with respect to each other to receive differing portions of the wafer.

18. The wafer transfer system of claim 16, wherein the translating means and the receiving means are mounted for rotation about a single axis.

19. The wafer transfer system of claim 18, wherein the translating means is mounted for a horizontal shift when in the vertical orientation away from the receiving means to free a wafer from the extraction structure, leaving the wafer in the vertical orientation supported solely by the receiving means.

20. The wafer transfer system of claim 16, wherein the translating means and the receiving means are mounted for rotation about differing axes, whereby the translating means and the receiving means traverse differing arcs during rotation to the vertical orientation and the wafer is freed from the translating means during rotation to the vertical orientation, leaving the wafer in the vertical orientation supported solely by the receiving means.

21. The wafer transfer system of claim 16, wherein the translating means and the receiving means are mounted for horizontal translation toward the wafer support device during rotation to the vertical orientation.

22. A process for moving a wafer horizontally into and out of a wafer support device to and from a position in which the wafer is maintained in a vertical orientation accessible for further processing, the wafer support device having opposed, paired shoulders on interior walls thereof to horizontally support the wafer, the support device further having a vertical opening therein, the process comprising:

providing a wafer transfer device comprising;

a base positioned adjacent the opening in the wafer support device,

an extraction structure mounted to the base for generally horizontal reciprocal movement into and out of the wafer support device for removing the wafer from the wafer support device along a generally horizontal path, the extraction structure further mounted to the base for rotation to a generally vertical orientation, and

a wafer support structure comprising wafer receiving elements disposed to receive the wafer from the extraction structure, the wafer support structure mounted to the base for rotation to a generally vertical orientation concurrently with the extraction structure;

moving the wafer by the extraction structure along a generally horizontal path out of the support device into contact with the wafer support structure; and

rotating the extraction structure and the wafer support structure concurrently to a generally vertical orientation.

23. The process of claim 22, wherein the rotating step comprises rotating the extraction structure and the wafer support structure about a single axis.

24. The process of claim 23, further comprising the step of shifting the extraction structure horizontally out of contact with the wafer, leaving the wafer supported by the wafer support structure.

25. The process of claim 22, wherein the rotating step comprises rotating the extraction structure and the wafer support structure about differing axes.

26. The process of claim 22, further comprising translating the extraction structure and the wafer support structure horizontally during the rotation step.