US 5,993,289 A · Methods for the in-process detection of workpieces in a CMP environment

Abstract

A method for detecting the presence of a workpiece on a polishing pad of a chemical mechanical polishing (CMP) machine applies an optical interrogation signal to a workpiece during the CMP process. An optical probe assembly produces a light signal that communicates with the polishing pad; portions of the light signal reflect from the polishing pad in a scattered manner. A light receptor receives reflected light associated with the interrogation signal, and the characteristics of the received light are analyzed and processed by a suitable processor. By analyzing the scattered light signals, the method distinguishes the reflective characteristics of the polishing pad from the reflective characteristics of the workpiece. Thus, the method may be used to detect a lost or broken workpiece in a fast and effective manner.

Claims16

Dependent claims

A method for detecting the presence of a workpiece on a polishing pad during a chemical mechanical polishing (CMP) procedure, said method comprising the steps of:

moving at least one workpiece on a surface of a rotating polishing pad such that said at least one workpiece is polished by said rotating polishing pad;
disposing a probe assembly above said surface such that said probe assembly engages said surface in a nonconducting manner during said CMP procedure;
applying an interrogation signal from said probe assembly to said surface;
capturing a scattered signal from said surface;
and
analyzing said scattered signal to thereby obtain substantially real time data pertaining to the absence or presence of a workpiece on said surface.

3 more elements

Dependencies are inferred from the claim text.

Methods for the in-process detection of workpieces in a CMP environment

Life of this patent

Methods for the in-process detection of workpieces in a CMP environment

Life of this patent

Abstract

Claims16