Resist development control system
US4142107A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1977 |
| Grant date | Feb 27, 1979 |
| Priority date | — |
| Expiry date | Jun 30, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/30
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In the process of developing exposed photoresist on a substrate, the endpoint in developing away all of the exposed positive photoresist or any other positive resist is detected by exposing a wafer with a predetermined pattern including an optical grating or other special pattern formed in the photoresist upon a test area. In a system employing this concept, a beam is diffracted by the optics of the grating only at a first angle until the resist forming the grating is removed by development. Then a sensor is activated when an angle of reflection is unblocked when the grating disappears. The system is then turned off to stop development by the sensor in an automatic system or, by the operator in a manual system. A double exposure technique is employed to produce the grating or other special pattern.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.