Sensors for a linear polisher

• US 5,762,536 A
• Filed: 02/06/1997
• Issued: 06/09/1998
• Est. Priority Date: 04/26/1996
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Lam Research Corporation
• Inventors: Engdahl, Erik H., Pant, Anil K., Breivogel, Joseph R., Young, Douglas W., Jairath, Rahul
• Primary Examiner(s): Eley, Timothy V.
• Assistant Examiner(s): BANKS, DERRIS HOLT
• Application Number:
  US08/797,470
• Time in Patent Office: 488 Days
• Field of Search: 451/296, 451/307, 451/5, 451/6, 451/8, 451/9, 451/10, 451/11, 451/303, 451/285, 451/287, 451/288, 451/41, 451/28
• US Class Current: 451/6
• CPC Class Codes: B24B 21/04 for grinding plane surfaces
• CPC Class Codes: B24B 21/08 Pressure shoes; Pressure members, e.g. backing belts
• CPC Class Codes: B24B 37/04 designed for working plane surfaces
• CPC Class Codes: B24B 49/16 taking regard of the load

Abstract

A technique for utilizing sensors to monitor the polishing of a semiconductor wafer when a linear polisher is utilized to polish the wafer. The sensors are distributed along the surface or are coupled to openings along the surface to monitor the on-going polishing process. The sensed information from the sensors are processed in order to provide feedback for compensating the fluid dispensing when fluid platens are used and/or the downforce exerted by the wafer carrier.

Claims

1. In a tool utilized to polish a material having a planar surface and in which said planar surface is placed upon a polishing pad for polishing said planar surface, an apparatus for determining a polishing force exerted onto said planar surface comprising:

a platen disposed along an underside of said pad opposite said surface;

a sensor coupled to said platen to measure a gap distance between said platen and said pad to determine said polishing force.

2. The apparatus of claim 1 wherein said sensor is a proximity sensor.

3. In a tool utilized to polish a material having a planar surface and in which said planar surface is placed upon a polishing pad for polishing said planar surface, an apparatus for determining a polishing force exerted onto said planar surface comprising:

a platen disposed along an underside of said pad opposite said surface;

a pressure sensor coupled to said platen to measure pressure being exerted on said platen to determine said polishing force.

4. In a linear polisher for performing chemical-mechanical polishing (CMP) on a surface of a substrate or a layer formed on said substrate, and in which said surface is placed upon a linearly moving polishing pad for polishing said surface, an apparatus for determining a separation distance of a region underlying said pad comprising:

a platen disposed along an underside of said pad opposite said surface;

plurality of sensors coupled to said platen to measure said separation distance between said platen and said pad or a belt upon which said pad is mounted at a plurality of locations along said platen.

5. The apparatus of claim 4 wherein said sensors are proximity sensors for measuring said separation distance.

6. The apparatus of claim 4 wherein said platen is a fluid platen, in which fluid is dispensed within said region, and measurement of said separation distance determines thickness of said fluid along said platen.

7. The apparatus of claim 6 wherein said sensors are utilized to obtain measurements at said plurality of locations to adjust one or more fluid dispensing channels of said platen.

8. In a linear polisher for performing chemical-mechanical polishing (CMP) on a surface of a substrate or a layer formed on said substrate, and in which said surface is placed upon a linearly moving polishing pad for polishing said surface, an apparatus for determining a pressure being exerted on a region underlying said pad comprising:

a platen disposed along an underside of said pad opposite said surface;

plurality of sensors coupled to said platen to measure said pressure being exerted on said platen at plurality of locations along a surface of said platen.

9. The apparatus of claim 8 wherein said platen is a fluid platen in which fluid is dispensed between said platen and said pad or a belt upon which said pad is mounted;

said platen also having openings formed along its surface in order for said fluid to flow therein; and

said sensors coupled to said openings to measure pressure of said fluid in said openings.

10. The apparatus of claim 9 wherein said sensors are utilized to obtain pressure measurements at said plurality of locations along said surface and in which said pressure measurements are used to adjust one or more fluid dispensing channels of said platen.

11. The apparatus of claim 9 wherein said sensors are utilized to obtain pressure measurements at said plurality of locations along said surface to obtain an average pressure profile across said platen and said average pressure profile is used to adjust a downforce of a carrier carrying said substrate.

12. In a linear polisher for performing chemical-mechanical polishing (CMP) on a surface of a substrate or a layer formed on a substrate, and in which said surface is placed upon a linearly moving polishing pad for polishing said surface, a method of monitoring a separating distance of a region underlying said pad, comprising the steps of:

placing a platen along an underside of said pad or a belt upon which said pad is mounted opposite said surface and in which said region resides between said platen and said pad or said belt upon which said pad is mounted;

coupling plurality of sensors to said platen to measure said separating distance of said region at a plurality of locations along said platen.

13. The method of claim 12 wherein said step of placing said platen places a fluid platen in which fluid is dispensed between said platen and said pad or a belt upon which said pad is mounted;

and measurement of said separating distance determines thickness of said fluid along said region.

14. The method of claim 13 further including the step of adjusting one or more fluid dispensing channels of said platen based on said measurements.

15. In a linear polisher for performing chemical-mechanical polishing (CMP) on a surface of a substrate or a layer formed on said substrate, and in which said surface is placed upon a linearly moving polishing pad for polishing said surface, a method of monitoring a pressure being exerted on a region underlying said pad, comprising the steps of:

placing a platen along an underside of said pad or a belt upon which said pad is mounted opposite said surface;

coupling plurality of sensors to said platen to measure said pressure being exerted on said platen at a plurality of locations along a surface of said platen.

16. The method of claim 15 wherein said step of placing said platen places a fluid platen in which fluid is dispensed between said platen and said pad or a belt upon which said pad is mounted;

and measurement of said pressure measures fluid pressure at said plurality of locations.

17. The method of claim 16 wherein said step of placing said fluid platen includes placing said fluid platen with openings formed along its surface for passage of said fluid therein for coupling to pressure sensors to measure pressure of said fluid at said plurality of locations.

18. The method of claim 17 further including the step of adjusting one or more fluid dispensing channels of said platen based on said measurements.

19. The method of claim 17 further including the step of averaging said measurements to adjust a force exerted by said substrate onto said pad.

20. The method of claim 15 wherein said step of coupling said sensors couples strain gauges to said surface of said platen.