Processing endpoint detecting technique and detector structure using multiple radiation sources or discrete detectors
US5362969A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 23, 1993 |
| Grant date | Nov 8, 1994 |
| Priority date | — |
| Expiry date | Apr 23, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/26
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A detector structure and technique for non-contact monitoring of a process being performed on a surface, such as in semiconductor wafer integrated circuit processing and flat panel display substrate processing, in order to determine when the process has reached endpoint. In one embodiment, multiple small area radiation sources, such as light emitting diodes, are symmetrically arranged around a large area photodetector, and each have similar radiation distribution patterns. In an alternative embodiment, multiple photodetectors are symmetrically arranged around a single light emitting diode with a symmetrical radiation distribution pattern. In either case, the amount of source radiation reflected onto the detector from the surface being processed is not significantly affected by any wobble or tilting of the surface that may occur during processing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.