Methods and apparatus for etching self-aligned contacts
US5783496A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 1996 |
| Grant date | Jul 21, 1998 |
| Priority date | — |
| Expiry date | Mar 29, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31116
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method in a plasma processing chamber for fabricating a semiconductor device having a self-aligned contact. The method includes the step of providing a wafer having a substrate, a polysilicon layer disposed above the substrate, a nitride layer disposed above a polysilicon layer, and an oxide layer disposed above the nitride layer. The method further includes the step of etching in a first etching step partially through the oxide layer of the layer stack with a first chemistry and a first set of process parameters. In this first etching step, the first chemistry comprises essentially of CHF.sub.3 and C.sub.2 HF.sub.5. The method also includes the step of etching the oxide layer in a second etching step through to the substrate with a second chemistry comprising CHF.sub.3 and C.sub.2 HF.sub.5 and a second set of process parameters. The second set of process parameters is different from the first set of process parameters and represents a set of parameters for etching the oxide layer with a higher oxide-to-nitride selectivity than the oxide-to-nitride selectivity achieved in the first etching step.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.