Methods for the in-process detection of workpieces in a CMP environment
US5993289A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 1998 |
| Grant date | Nov 30, 1999 |
| Priority date | — |
| Expiry date | Mar 5, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/45232
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.