Method and composite hard mask for forming deep trenches in a semiconductor substrate
US7138338B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 2004 |
| Grant date | Nov 21, 2006 |
| Priority date | — |
| Expiry date | Jul 14, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D1/047
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method and structure for forming deep trenches in a semiconductor substrate is provided. The method comprises: providing a semiconductor substrate; forming a pad oxide layer on the semiconductor substrate; forming a pad nitride layer on the pad oxide layer; forming a borophosphosilicate glass layer on the pad nitride layer; forming a borosilicate glass layer on the borophosphosilicate glass layer; and forming deep trenches through the borosilicate glass layer, through the borophosphosilicate glass layer, through the pad nitride, through the pad oxide, and into the semiconductor substrate. The borosilicate glass layer and the borophosphosilicate glass layer function as a composite hard mask in forming the deep trenches. With the borophosphosilicate glass layer, the composite hard mask can be easily removed by dry etch process using hydrogen fluoride vapor after the deep trenches have been formed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.