Process for control of the shape of the etch front in the etching of polysilicon
US6074954A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1998 |
| Grant date | Jun 13, 2000 |
| Priority date | — |
| Expiry date | Aug 31, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D1/047
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The present disclosure pertains to our discovery that the use of a particular combination of etchant gases results in the formation of a substantially flat etch front for polysilicon etching applications. In general, the process of the invention is useful for controlling the shape of the etch front during the etchback of polysilicon. Typically, the process comprises isotropically etching the polysilicon using a plasma produced from a plasma source gas comprising a particular combination of reactive species which selectively etch polysilicon. The plasma source gas comprises from about 80% to about 95% by volume of a fluorine-comprising gas, and from about 5% to about 20% by volume of an additive gas selected from a group consisting of a bromine-comprising gas, a chlorine-comprising gas, an iodine-comprising gas, or a combination thereof. One preferred mixture is SF.sub.6, Cl.sub.2 and HBr. A preferred method of the invention, used to perform recess etchback of a polysilicon-filled trench in a substrate, comprises the following steps: a) providing a trench 3 formed in a semiconductor structure, wherein the structure includes a substrate 2, at least one gate dielectric layer 6 overlyi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.