Apparatus for endpoint detection during mechanical planarization of semiconductor wafers

Patent 5069002 Issued on December 3, 1991. Estimated Expiration Date:

April 17, 2011. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Inventors

Application

No. 686686 filed on 04/17/1991

US Classes:

451/1, PRECISION DEVICE OR PROCESS - OR WITH CONDITION RESPONSIVE CONTROL216/38, PLANARIZING A NONPLANAR SURFACE216/84, With measuring, testing, or inspecting257/E21.244, Involving dielectric removal step (EPO)438/692, Simultaneous (e.g., chemical-mechanical polishing, etc.)438/959, MECHANICAL POLISHING OF WAFER451/41, Glass or stone abrading451/287Planar surface abrading

Examiners

Primary: Parker, Roscoe V.

Attorney, Agent or Firm

Crowder; Albert M.

International Classes

B24B 049/16
H01L 021/304

Abstract

An apparatus for detecting a planar endpoint on a semiconductor wafer during mechanical planarization of the wafer. The planar endpoint is detected by sensing a change in friction between the wafer and a polishing surface. This change of friction may be produced when, for instance, an oxide coating of the wafer is removed and a harder material is contacted by the polishing surface. In a preferred form, the change in friction is detected by rotating the wafer and polishing surface with electric motors and measuring current changes on one or both of the motors. This current change can then be used to produce a signal to operate control means for adjusting or stopping the process.