Production method of a semiconductor dynamic sensor
US5643803A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 1993 |
| Grant date | Jul 1, 1997 |
| Priority date | — |
| Expiry date | Sep 17, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/924
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
It is intended to provide an etching method for semiconductor devices in which the etching depth or the thickness of a thin thickness portion can be precisely controlled. According to experiment results, when a P-type substrate in which an N-type epitaxial layer is formed is immersed in an etching solution such as KOH or the like, and a voltage for reverse bias of PN junction is applied between an electrode plate opposing the substrate and the epitaxial layer to perform electrochemical etching, it has been found that the distance from the PN junction plane to the etching stop position is approximately equal to a depletion layer width at the substrate side of the PN junction portion. Namely, the etching stops at the forward end of the depletion layer. Therefore, the junction depletion layer width at the substrate side is controlled to be a size obtained by subtracting a necessary depth for etching from a thickness of the semiconductor substrate except for the semiconductor layer, so that the etching depth or the thickness of the thin thickness portion remaining after etching can be precisely controlled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.