Single crystal silicon dry-etch endpoint based on dopant-dependent and thermally-assisted etch rates
US5591300A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Jan 7, 1997 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/3065
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A dry etching method for endpoint detection of a single crystal silicon wafer is disclosed. A top portion of the single crystal silicon wafer is doped with heavy levels of a doping agent, thereby creating heavily and lightly doped regions within the single crystal silicon wafer. A photoresist is patterned on the top surface of the single crystal silicon wafer and etching commences on the top surface. The etch rate is monitored as the etch progresses through the top portion of the single crystal silicon wafer to determine the etch endpoint. The etch endpoint is detected by a local minimum generated by the combined effects of wafer surface thermal heating and the change or etch rate between the heavily doped single crystal silicon and lightly doped single crystal silicon. Once the etch endpoint has been detected, the etching process is stopped, and the photoresist is removed, thereby exposing a doped product.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.