Semiconductor wafer processing with across-wafer critical dimension monitoring using optical endpoint detection
US5427878A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 16, 1994 |
| Grant date | Jun 27, 1995 |
| Priority date | — |
| Expiry date | May 16, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/0683
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for across-wafer critical dimension uniformity performance monitoring in the manufacture of semiconductor devices employs a number of optical endpoint detectors at sites at the wafer face which are spaced across the wafer face. Each optical endpoint detector is able to directly measure the end point of the process step at its site. One of these optical endpoint detectors is used to control the process, and when the endpoint has been reached for this site the process completion time is predicted and this completion time is used to control the processing equipment. For example, if the process step being monitored is the development of photoresist, then the developing operation is ended based upon this calculated completion time derived from the detected endpoint for the control site. The other sites are used to monitor across-wafer performance. The output of each of these other optical detectors is used to determine the endpoint for each monitor site, and these endpoints are compared with the control endpoint to determine across-wafer critical dimension performance and conformance to specification. The wafers can thus be flagged if out-of-limit, and need not be processed thr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.