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Title:
APPARATUS AND METHOD FOR CHEMICAL-MECHANICAL POLISHING (CMP) USING A HEAD HAVING DIRECT PNEUMATIC WAFER POLISHING PRESSURE SYSTEM
Document Type and Number:
WIPO Patent Application WO/2000/051782
Kind Code:
A1
Abstract:
A resilient pneumatic annular sealing bladder (550) is coupled for fluid communication to a first pressurized pneumatic fluid to define a first pneumatic zone (556) and is attached to a first surface (562) of the wafer stop plate (554) adjacent the retaining ring (166) interior cylindrical surface to receive the wafer (113) and to support the wafer at a peripheral edge (557). The resilient pneumatic annular sealing bladder (550) defines a second pneumatic zone (558) radially interior to the first pneumatic zone (557) and extends between the first surface (562) of the wafer stop plate (554) and the wafer (113) when the wafer (173) is attached to the polishing head (559) during a polishing operation and is coupled for fluid communication to a second pressurized pneumatic fluid. The wafer attachment stop plate (554) is operative during non polishing periods to prevent the wafer (113) from flexing excessively from an applied vacuum force used to hold the wafer to the polishing head during wafer loading and unloading operations.

Inventors:
Moloney, Gerard S. (74 Washington Square Drive Milpitas, CA, 95035, US)
Price, Jason (271 Briarcliff Drive, No. 6 Eugene, OR, 97404, US)
Chin, Scott (473 Pepper Drive Palo Alto, CA, 94306, US)
Kajiwara, Jiro (20651 Forge Way, No. 150 Cupertino, CA, 95014, US)
Charif, Malek (5293 Joseph Lane San Jose, CA, 95118, US)
Application Number:
PCT/IB2000/000513
Publication Date:
September 08, 2000
Filing Date:
March 01, 2000
Export Citation:
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Assignee:
MITSUBISHI MATERIALS CORPORATION (1-5-1 Ohtemchi Chiyoda-ku Tokyo, 100-8117, JP)
International Classes:
B24B37/30; B24B37/32; B24B41/06; B24B49/16; H01L21/304; (IPC1-7): B24B37/04; B24B41/06
Foreign References:
US5584751A
US5635083A
EP0841123A1
EP0847835A1
EP0881039A2
EP0747167A2
Download PDF:
Description:
applying pressure to a substrate retaining ring, substrate sub-cazIier, pneumatic bladder pressing a portion of said substrate against a polishing surface, and back-side surface of said substrate substantially independently of each other.

3. In a semiconductor wafer polishing machine of the type having a retaining ring for retaining the wafer to a wafer carrier during polishing against a polishing pad, the polishing machine characterized in that a diaphragm mounts said wafer and is supported from a floating retaining ring.

4. In a semiconductor wafer polishing machine of the type having a retaining ring for retaining the wafer to a wafer carrier during polishing against a polishing pad, the polishing machine characterized in that an open diaphragm support from floating retaining ring is used to press said wafer against said polishing pad.

5. A wafer polishing head for polishing a semiconductor wafer on a polishing pad, said polishing head comprising : a retaining ring having an interior cylindrical surface and defining an interior cylindrical pocket sized to carry said wafer and to laterally restrain movement of said wafer when said wafer is moved relative to said polishing pad while being polished against said polishing pad, said retaining ring having a lower surface that is pressed against said polishing pad by a first pressurized fluid to define a first pressure zone during polishing of said wafer; a wafer attachment stop plate attached to said retaining ring; a resilient pneumatic annular sealing bladder coupled for fluid communication to a second pressurized fluid to define a second pressure zone and attached to a first surface of said wafer stop plate adjacent said retaining ring interior cylindrical surface to receive said wafer and to support said wafer proximate a peripheral edge; said resilient pneumatic annular sealing bladder defining a third pressure zone radially interior to said second pressure zone and extending between said first surface of said wafer stop plate and said wafer when said wafer is attached to said polishing head during a polishing operation and coupled for fluid communication to a third pressurized fluid, said first surface of said wafer stop plate not being in contact with a wafer back side surface during polishing of said wafer ;

said wafer attachment stop plate operative during non-polishing periods to prevent said wafer from flexing an amount that would damage the structure of said wafer from an applied vacuum force used to hold said wafer to said polishing head ; said first, said second, and said third pressurized fluids being adjusted to achieve a predetermined polishing pressure profile over a front side surface of said wafer.

6. A wafer polishing head for polishing a semiconductor wafer on a polishing pad, said polishing head comprising : a retaining ring having an interior cylindrical surface and defining an interior cylindrical pocket sized to carry said wafer and to laterally restrain movement of said wafer when said wafer is moved relative to said polishing pad while being polished against said polishing pad, said retaining ring having a lower surface that is pressed against said polishing pad by a first pressurized fluid to define a first pressure zone of said retaining ring against said polishing pad during polishing of said wafer ; a wafer attachment stop plate attached to said retaining ring ; and a resilient seal disposed adjacent said retaining ring interior cylindrical surface to receive said wafer and to support said wafer at a peripheral edge and defining a second pressure zone between said wafer and said polishing pad when said wafer has been mounted to said head that is coupled for fluid communication to a second pressurized fluid ; said wafer attachment stop plate operative during non-polishing periods to prevent said wafer from flexing e an amount that would damage the structure of said wafer from an applied vacuum force used to hold said wafer to said polishing head during wafer loading and unloading operations; said first and said second pressurized fluids being adjusted to achieve a predetermined polishing pressures over a front side surface of said wafer.

7. A wafer polishing head for polishing a semiconductor wafer on a polishing pad, said polishing head comprising: a retaining ring having an interior cylindrical surface and defining an interior cylindrical pocket sized to carry said wafer and to laterally restrain movement of said wafer when said wafer is moved relative to said polishing pad while being polished

against said polishing pad, said retaining ring having a lower surface that is pressed against said polishing pad by a first pressurized fluid to define a first pressure zone of said retaining ring against said polishing pad during polishing of said wafer; a wafer attachment stop plate attached to said retaining ring ; and a plurality of resilient pneumatic bladders attached to a first surface of said wafer stop plate, each said bladder being coupled for fluid communication to a source of pressurized fluid; a first one of said plurality of resilient pneumatic bladders having an annular shape and disposed adjacent said retaining ring interior cylindrical surface to receive said wafer and to support said wafer proximate a peripheral edge, said first bladder being coupled for fluid communication to a second pressurized pneumatic fluid; a second one of said plurality of resilient pneumatic bladders disposed between said annular shaped first bladder and a central portion of said cylindrical pocket and coupled for fluid communication to a third pressurized pneumatic fluid ; said first, said second, and said third pressurized fluids being adjusted to achieve a predetermined polishing pressures over a front side surface of said wafer.

8. A wafer polishing head for polishing a semiconductor wafer on a polishing pad, said polishing head comprising : a retaining ring having an interior cylindrical surface and defining an interior cylindrical pocket sized to carry said wafer and to laterally restrain movement of said wafer when said wafer is moved relative to said polishing pad while being polished against said polishing pad, said retaining ring having a lower surface that is pressed against said polishing pad by a first pressurized fluid to define a first pressure zone of said retaining ring against said polishing pad during polishing of said wafer ; a wafer attachment stop plate attached to said retaining ring; said wafer attachment stop plate having a plurality of resilient concentric annular sealing ridges extending from a surface of said stop plate and defining substantially independent pneumatic pressure zones when pressed against a back side surface of said wafer, each said pneumatic pressure zone being coupled for fluid communication to a source of pressurized pneumatic fluid; a first one of said plurality of resilient concentric annular sealing ridges being disposed adjacent said retaining ring interior cylindrical surface to receive said wafer

and to support said wafer proximate a peripheral edge and defining a second pneumatic pressure zone, said second pneumatic pressure zone being coupled for fluid communication to a second pressurized pneumatic fluid ; a second one of said plurality ofresilient concentric annular sealing ridges being disposed interior to said first annular sealing ridges and coupled for fluid communication to a third pressurized pneumatic fluid; said first, said second, and said third pressurized fluids being adjusted to achieve a predetermined polishing pressure profile between said polishing pad and a front side surface of said wafer during polishing.

9. A method for polishing a semiconductor wafer on a polishing pad, said method comprising: defining a first annular pneumatic pressure zone with a first sealing bladder; defining a second pneumatic pressure zone radially interior to said first pneumatic zone with a second sealing bladder; developing first and second pressures respectively in said first and said second sealing bladders; directly pressing a backside surface of said wafer with said first and second sealing bladders without an intervening rigid member so that a front side surface of said wafer is pressed against said polishing pad; and adjusting said first and second pressures independently to achieve a desired wafer material remove characteristic across said front side surface of said wafer.

10. The method in Claim 9 wherein said desired wafer material removal characteristic comprises substantially uniformmaterial across said front surface of said wafer.

11. A semiconductor wafer made by the process in Claim 9.

12. The method of polishing in Claim 2, wherein said substrate comprises a semiconductor wafer.

13. The method in Claim 9, further comprising the steps of : retaining said wafer within a cylindrical pocket defined by a retaining ring and sized to carry said wafer and to laterally restrain movement of said wafer when said wafer is moved relative to said polishing pad during polishing; and defining an annular retaining ring pressure zone surrounding and substantially concentric with said first annular pneumatic pressure zone to press a contact surface of a retaining ring against said polishing pad during polishing.

14. The method of Claim 13, wherein said annular retaining ring pressure zone is defined to be a pressure that alters the wafer material removal rate proximate the peripheral edge of the wafer to reduce under removal or over removal of material from the front side surface of said wafer relative to interior portions of the wafer.

15. A wafer polishing head for polishing a substrate on a polishing surface, said polishing head comprising: a housing; a retaining ring defining a pocket sized to carry said substrate and to restrain movement of said substrate when said substrate is moved relative to said polishing pad while being polished against said polishing pad; a substrate subcarrier attached to said retaining ring by a primary diaphragm and to said housing by a secondary diaphragm; a resilient pneumatic annular sealing bladder coupled for fluid communication to a first pressurized pneumatic fluid to define a first pneumatic zone to receive said substrate and to support said substrate at a peripheral edge; and said resilient pneumatic annular sealing bladder defining a second pneumatic zone radially interior to said first pneumatic zone when said substrate is attached to said polishing head during a polishing operation and coupled for fluid communication to a second pressurized pneumatic fluid ; said first and said second pressurized fluids being adjusted to achieve predetermined polishing pressures over regions of a front-side surface of said substrate.

16. The wafer polishing head in Claim 15, said head further comprising: a stop plate separated from said substrate during polishing but disposed adjacent to at least a portion of said substrate to limit the movement of portions of said substrate during non-polishing substrate handling operations; said resilient pneumatic annular sealing bladder being attached to a first surface of said substrate stop plate adjacent said retaining ring interior cylindrical surface to receive said substrate and to support said substrate at a peripheral edge ; said resilient pneumatic annular sealing bladder extending between said first surface of said substrate stop plate and said substrate when said substrate is attached to said polishing head during a polishing operation; and said first surface of said substrate stop plate not being in contact with a substrate back-side surface during polishing of said substrate.

17. The wafer polishing head in Claim 15, wherein said stop plate is provided adjacent only over a central portion of said substrate.

18. The wafer polishing head in Claim 16, wherein said stop plate is provided adjacent substantially over an entire back-side surface of said substrate.

19. The waferpolishing head in Claim 15, wherein said substrate comprises a semiconductor wafer.

20. The wafer polishing head in Claim 16, wherein said substrate comprises a semiconductor wafer.

21. The wafer polishing head in Claim 15, wherein said substrate comprises a semiconductor wafer and said polishing comprises planarization of electronic circuit elements deposited on said semiconductor wafer.

22. In a wafer processing machine, a method for removing material from the surface of a substrate, said method comprising :

defining a pocket sized to carry said substrate and restraining movement of said substrate within said pocket when said substrate is moved relative to a polishing pad during processing; a substrate subcarrier attached to said retaining ring by aprimary diaphragm and to said housing by a secondary diaphragm; defining a first pneumatic pressure zone using a resilient pneumatic annular sealing bladder coupled for fluid communication to a first pressurized pneumatic fluid and receiving and supporting said substrate at a peripheral edge by said annular sealing bladder; defining a second pneumatic zone radially interior to said first pneumatic zone with said resilient pneumatic annular sealing bladder when said substrate is attached to said polishing machine against said sealing bladder during a processing operation, said second pneumatic pressure zone being coupled for fluid communication to a second pressurized pneumatic fluid; and adjusting said first and said second pressurized fluids independently to achieve predetermined material removal pressures over regions of a front-side surface of said substrate.

23. The method in Claim 22, further comprising the step of : limiting flexing movement of portions of said substrate during non-substrate processing operations on said substrate with a plate aligned substantially adjacent to an parallel with a portion of a back-side surface of said substrate, said plate not being in contact with said substrate back-side surface during polishing of said substrate.

24. The method in Claim 22, wherein said substrate comprises a semiconductor wafer.

25. The method in Claim 22, wherein said processing operation comprises a substrate polishing operation.

26. The method in Claim 22, wherein said substrate comprises a semiconductor wafer and said processing operation comprises a semiconductor wafer polishing operation.

27. The method in Claim 22, wherein said substrate comprises a semiconductor wafer and said processing operation comprises a semiconductor wafer planarization operation.

28. A semiconductor wafer fabricated according to the method in Claim 22.

29. A semiconductor wafer fabricated according to the method in Claim 22.