Adjustable method for eliminating trench top corners
US5962342A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 1997 |
| Grant date | Oct 5, 1999 |
| Priority date | — |
| Expiry date | Dec 18, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76232
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An adjustable method for making trenches for a semiconductor IC device having eliminated top corners is disclosed. The adjustable method includes forming a masking layer on the surface of the silicon nitride layer covering the device substrate that has openings corresponding to the openings of the trenches formed. Dimension of the masking layer opening is relatively greater than the dimension of the opening of the corresponding trench. An anisotropic etching procedure is then performed against the portions of the device substrate exposed out of the coverage of the masking layer, and the anisotropic etching shapes the trench sidewalls into sloped ones having larger dimension at the opening than at the surface of the filling material inside the trenches. This eliminates the top corners at the edges of the trench opening, charge accumulation and consequent leakage current can thus be prevented.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.