Dry etching process for semiconductor
US5871659A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 1996 |
| Grant date | Feb 16, 1999 |
| Priority date | — |
| Expiry date | Jun 18, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/3065
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A process for dry etching a silicon substrate, in which a mask exposing a region of the surface of the silicon substrate is formed, and the exposed region is dry etched. The dry etching is performed with a gas mixture including chlorine or a chlorine-containing gas, an oxygen-containing gas, and a fluorine-containing gas in which a ratio of a flow rate of oxygen gas to a flow rate of chlorine gas, O.sub.2 /Cl.sub.2, is selected to be from 0.6 to 3. The gas mixture may also contain a fluorine-containing gas and helium. Preferably, the gas mixture excludes carbon-containing gases. The dry etching process allows for an increased etch rate, as well as a high etch selectivity compared to that of SiO.sub.2 gas. The trench formed in the substrate by this process can be made of a larger depth with high reproducibility and good configuration. The sidewall profile angle of the trench is maintained slightly tapered, with a sidewall profile angle of approximately 90 degrees. Also, by mixing HBr gas into the gas mixture, it is possible to better control the formation of the trench. Thus, this process makes it possible to form, in a silicon substrate, a regularly configured and very deep trench …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.