Forming of close thin trenches
US6972240B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 19, 2003 |
| Grant date | Dec 6, 2005 |
| Priority date | — |
| Expiry date | Apr 21, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76229
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for forming narrow trenches in a silicon substrate, comprising the steps of: etching the substrate to form first trenches separated by first silicon ribs; performing a thermal oxidation of the substrate to form a silicon oxide layer around the substrate, to obtain second trenches and second silicon ribs; filling the second trenches with fingers of an etchable material; etching the oxide down to the upper surface of the second ribs while keeping oxide portions between said material fingers and the second ribs; etching away the second silicon ribs and said material fingers; etching the oxide to expose the substrate at the bottom of the oxide portions, while keeping oxide fingers; and etching the substrate between the oxide fingers to form narrow trenches in the substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.