Wafer scrubbing machine

• US 6,055,694 A
• Filed: 11/30/1998
• Issued: 05/02/2000
• Est. Priority Date: 11/30/1998
• Status: Expired due to Fees

• Current Assignee: Accretech USA Incorporated (Tokyo Seimitsu Company Limited)
• Original Assignee: TSK America Incorporated
• Inventors: Steere, Colby R.
• Primary Examiner(s): Warden, Sr., Robert J.
• Assistant Examiner(s): ALDAG, ANDREW J
• Application Number:
  US09/201,291
• Time in Patent Office: 519 Days
• Field of Search: 15/21.1, 15/77, 15/88.2, 15/88.3, 15/88.4, 15/102, 414/937, 414/938, 414/940, 414/941
• US Class Current: 15/77
• CPC Class Codes: H01L 21/6704 for wet cleaning or washing
• CPC Class Codes: H01L 21/67046 using mainly scrubbing means, e.g. brushes
• CPC Class Codes: Y10S 414/138 Wafers positioned vertically within cassette

Abstract

A wafer scrubbing machine is provided with a network of wafer holders which can be moved from a retracted position adjacent each other at a wafer receiving station to an expanded position spaced apart from each within a scrubbing station. The wafers are picked up simultaneously by pairs of depending arms in the scrubbing station and passed between pairs of rotating brushes for cleaning purposes. A common drive wheel is provided to rotate the wafers simultaneously during scrubbing between the brushes. A second network of wafer holders is provided to receive the scrubbed wafers in the scrubbing station and to move into a retracted position within a delivery station for transfer of the cleaned wafers into a cassette for subsequent processing. Two sets of networks may be provided on a common rotatable assembly in order to accommodate two different sizes of delivered wafers.

Claims

1. A wafer scrubbing machine comprising

a first wafer holder network including a plurality of holders, each holder being disposed to receive a wafer in a vertically upstanding manner and an actuator system for moving said holders relative to each other between a retracted first position with said holders adjacent each other and an expanded second position with said holders in spaced apart relation to each other;

a plurality of parallel rotatably mounted brushes; and

a transfer conveyor for simultaneously moving a plurality of wafers from said holders in said second position thereof into and between said brushes for scrubbing of each wafer between a pair of adjacent brushes.

2. A wafer scrubbing machine as set forth in claim 1 further comprising

a second wafer holder network including a plurality of holders and means for moving said holders relative to each other between an expanded position with said holders in spaced apart relation to each other to receive a plurality of wafers from said transfer conveyor and a retracted position with said holders adjacent each other.

3. A wafer scrubbing machine as set forth in claim 2 which further comprises a receiving station for receiving a cassette of wafers and for transferring the wafers in a cassette into said holders of said first wafer holder network and a delivery station for transferring the scrubbed wafers into a cassette, said delivery system being adjacent to said second wafer holder network when said second wafer holder network is in said retracted position.

4. A wafer scrubbing machine as set forth in claim 1 wherein said transfer conveyor includes a plurality of pairs of depending arms for movement between a respective pair of said brushes, a guide on a lower end on each arm for engaging a peripheral edge of a wafer mounted on a respective holder, a rotatable wheel mounted intermediately of each arm for engaging the peripheral edge of a wafer and a spreader assembly for moving at least one of said arms relative to the other of said arms to selectively engage each said guide and said wheel with a respective wafer.

5. A wafer scrubbing machine as set forth in claim 4 which further includes means for rotating an engaged wafer during passage between a respective pair of said brushes.

6. A wafer scrubbing machine as set forth in claim 1 wherein said holders are disposed on a pitch of 10 millimeters in said retracted position.

7. A wafer scrubbing machine as set forth in claim 1 which further comprises a catch basin below said brushes thereof to receive used cleaning fluid.

8. A wafer scrubbing machine as set forth in claim 1 wherein said actuator system for moving said holders is connected to a foremost holder of said holders for moving said foremost holder between said positions of said holders and includes a plurality of longitudinally collapsible links connected to and between each pair of adjacent holders to transfer a forward motion therebetween.

9. A wafer scrubbing machine as set forth in claim 8 which further comprises a plurality of guide pins, each pin being secured to a selected one of said holders and passing through a plurality of said holders for guiding said holders relative to each other.

10. A wafer scrubbing machine as set forth in claim 1 wherein each holder has an arcuate recess in a top surface thereof to receive a wafer in upstanding relation.

11. A wafer scrubbing machine as set forth in claim 10 wherein each recess has a width of 0.0394 inches.

12. A wafer scrubbing system as set forth in claim 1 wherein said actuator system includes an endless cable extending parallel to a path of a foremost one of said holders between said retracted position and said expanded position, a bracket secured to and between said cable and a foremost one of said holders, and a pneumatic actuator connected to said cable for driving said cable to effect movement of said bracket and said foremost holder between said positions of said holders.

13. A wafer scrubbing assembly comprising

a wafer holder network including a plurality of holders for receiving wafers in a vertically upstanding manner and being movable relative to each other between a retracted position with said holders adjacent each other and an expanded position with said holders in spaced apart relation to each other;

a plurality of parallel rotatably mounted brushes disposed above said holders when said holders are in said expanded position thereof; and

a transfer conveyor for simultaneously moving a plurality of wafers vertically between said holders in said expanded position thereof and said brushes.

14. A wafer scrubbing machine as set forth in claim 13 wherein said transfer conveyor includes a plurality of pairs of depending arms for movement between a respective pair of said brushes, at least one of said arms being movable laterally relative to the other arm of said pair of arms, a guide on a lower end of each arm for engaging a peripheral edge of a wafer mounted on a respective holder and a rotatable wheel mounted intermediately of each arm for engaging the peripheral edge of a wafer.

15. A wafer scrubbing machine as set forth in claim 14 which further includes a rotatable drive shaft for rotating a plurality of engaged wafers simultaneously during passage between a respective pair of said brushes.

16. A wafer scrubbing machine as set forth in claim 15 further comprising a spring biasing a respective wheel against a wafer received between said arms to bias the wafer against said drive shaft.

17. A wafer scrubbing machine as set forth in claim 14 wherein each holder includes a projection and wherein each pair of arms includes at least one depending guide piece having a groove therein for receiving said projection to align said pair of arms with a respective holder during transfer of a wafer therebetween.

18. A wafer scrubbing machine as set forth in claim 13 wherein each holder includes a main body part of metal and a wafer holding part of plastic removably mounted on said main body part, said wafer holding part defining a recess therebetween for receiving a minor portion of a wafer.

19. A wafer scrubbing station as set forth in claim 13 which further comprises an actuator system for driving a foremost one of said holders between said retracted position and said expanded position, said actuator system including an endless cable extending parallel to a path of a foremost one of said holders between said retracted position and said expanded position, a bracket secured to and between said cable and the foremost holder, and a pneumatic actuator connected to said cable for driving said cable to effect movement of said bracket and said foremost holder between said positions of said holders.

20. A wafer scrubbing machine comprising

a receiving station for receiving a cassette of wafers;

a scrubbing station including a first wafer holder network including a plurality of holders, each holder being disposed to receive a wafer in a vertically upstanding manner, means for moving said holders relative to each other between a retracted position at said receiving station with said holders adjacent each other and an expanded position with said holders in spaced apart relation to each other, a plurality of parallel rotatably mounted brushes above said holders when said holders are in said expanded position thereof, a transfer conveyor for simultaneously moving a plurality of wafers from said holders in said expanded position thereof into and between said brushes for scrubbing of each wafer between a pair of adjacent brushes, and a second wafer holder network including a plurality of second holders and an actuator system for moving said second holders relative to each other between an expanded position with said second holders in spaced apart relation to each other to receive a plurality of wafers from said transfer conveyor and a retracted position with said second holders adjacent each other; and

a delivery station for delivering wafers from said second wafer holder network to a cassette, said delivery station being adjacent to said second wafer holder network when said second wafer holder network is in said retracted position.

21. A wafer scrubbing machine as set forth in claim 20 wherein said transfer conveyor includes a plurality of pairs of depending arms for movement between a respective pair of said brushes, at least one of said arms of each pair of arms being movable laterally relative to the other of said arms of said pair of arms, a guide on a lower end on each arm for engaging a peripheral edge of a wafer mounted on a respective holder and a rotatable wheel mounted intermediately of each arm for engaging the peripheral edge of a wafer.

22. A wafer scrubbing machine as set forth in claim 21 which further includes a rotatable drive shaft for rotating a plurality of engaged wafers simultaneously during passage between a respective pair of said brushes.

23. A wafer scrubbing machine as set forth in claim 20 which further comprises a catch basin below said brushes to receive used cleaning fluid.