Claims
- 1. Apparatus for detecting disengagement of a workpiece comprising:a polishing head having a first portion and a second portion; and a detector adapted to provide a metric indicative of relative motion between the first portion and the second portion.
- 2. The apparatus of claim 1, wherein the detector is an accelerometer, a limit switch, a proximity sensor, a Hall effect sensor, an optical encoder or a reed switch.
- 3. The apparatus of claim 1, wherein the detector is a linear voltage displacement transducer.
- 4. The apparatus of claim 3, wherein the transducer further comprises:a sensor body; and a piston extending movably from the sensor body and in contact with the first portion.
- 5. The apparatus of claim 1 further comprising:a column supporting the polishing head; and a bracket coupling the detector to the column.
- 6. The apparatus of claim 1, wherein the first portion comprises at least a carrier plate, a cover or a retaining ring.
- 7. The apparatus of claim 1, wherein the first portion comprises a cover having a surface adapted to interface with the detector.
- 8. The apparatus of claim 1, wherein the polishing head further comprises a flexure coupling the second portion to the first portion.
- 9. The apparatus of claim 8, wherein the flexure is coupled between a retaining ring and the second portion.
- 10. The apparatus of claim 1, wherein the polishing head further comprises a biasing device disposed between the first portion and the second portion.
- 11. The apparatus of claim 1, wherein the metric is a change in voltage.
- 12. The apparatus of claim 1, wherein the first portion moves in response to movement of the workpiece normal to a polishing material as the workpiece is polished on the polishing material.
- 13. Apparatus for detecting disengagement of a workpiece comprising:a polishing material; a polishing head for retain the workpiece against the polishing material during polishing; and a detector adapted to provide a metric indicative of relative motion between the polishing material and the polishing head.
- 14. The apparatus of claim 13, wherein the detector is a linear voltage displacement transducer, an accelerometer, a limit switch, a proximity sensor, a Hall effect sensor, an optical encoder or a reed switch.
- 15. Apparatus for detecting disengagement of a workpiece comprising:a polishing head having a first portion and a second portion; and a means for detecting relative motion between the first portion and the second portion.
- 16. The apparatus of claim 15, wherein the means for detecting is an accelerometer, a limit switch, a proximity sensor, a Hall effect sensor, an optical encoder, linear voltage displacement transducer or a reed switch.
- 17. Apparatus for detecting disengagement of a workpiece comprising:a platen; a polishing material disposed on the platen; a polishing head supported above the polishing material, the polishing head having a first portion and a second portion; and a detector adapted to provide a metric indicative of motion between the first portion and the second portion.
- 18. The apparatus of claim 17, wherein the platen is stationary.
- 19. The apparatus of claim 17, wherein the platen rotates.
- 20. The apparatus of claim 17, wherein the polishing head moves laterally relative to the platen during processing.
- 21. A method for detecting disengagement of a workpiece from a polishing head comprising:pressing the workpiece retained in the polishing head against a polishing material; providing relative motion between the workpiece and the polishing material; and detecting motion of the polishing head in a direction normal to the polishing material.
- 22. The method of claim 21, wherein the step of detecting motion further comprises the step of moving a first portion of the polishing head relative to a second portion.
- 23. The method of claim 22, wherein the step of detecting motion further comprises establishing a baseline or process window.
- 24. The method of claim 23, wherein the step of detecting motion further comprises the step of detecting motion of the first portion outside of the process window.
- 25. The method of claim 21, wherein the step of detecting motion further comprises the step of moving a piston coupled to a sensor.
- 26. The method of claim 25, wherein the sensor is a linear voltage displacement transducer.
- 27. The method of claim 21, wherein the step of providing relative motion between the workpiece and the polishing material further comprises the step of polishing the workpiece.
Parent Case Info
This application claims benefit of U.S. Provisional Patent Application Ser. No. 60/185,787, filed Feb. 29, 2000, which is hereby incorporated herein by reference in its entirety.
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