Shallow trench isolation method providing rounded top trench corners
US6174786A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 23, 1999 |
| Grant date | Jan 16, 2001 |
| Priority date | — |
| Expiry date | Nov 23, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76232
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of shallow trench isolation by forming a trench in a semiconductor device comprises the steps of forming an oxide layer; forming a mask layer; anisotropically etching the mask layer; forming a second oxide layer; forming a cap layer; forming rounded end caps adjacent the mask; and transferring the rounding of the caps to the top corners of the trench. The oxide layer is formed over a substrate of the semiconductor device. The mask layer is formed over the oxide layer. The mask layer is then anisotropically etched to form the mask and an opening in the mask. The opening in the mask exposes the substrate, and the width of the opening is greater than the width of the trench. Blanket etching the cap layer forms the rounded end caps. The rounded end caps are adjacent to the mask on opposite ends of the opening, and the distance between the end caps is about equal to the width of the trench. The trench is formed by plasma etching the trench. During this process, the rounding of the end caps is transferred to the top corners of a trench.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.