Silicon chemical mechanical polish etch (CMP) stop for reduced trench fill erosion and method for formation
US5837612A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 1, 1997 |
| Grant date | Nov 17, 1998 |
| Priority date | — |
| Expiry date | Aug 1, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/05
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for forming shallow trench isolation (STI) (100) begins by forming an oxidizable layer (106) preferably made of polysilicon. An opening is patterned and etched through this layer (106) to define and form the trench isolation region (108). Silicon sidewalls of the trench (108) and the polysilicon layer (106) are then exposed to an oxidizing ambient to form a thermal oxide trench liner (107a) and an erosion-protection polysilicon-oxide layer (107b). A trench fill material (110a) is then deposited and chemically mechanically polished (CMP) utilizing the polysilicon layer (106) as a polish stop. The final polished trench fill plug comprises an ozone TEOS bulk material (110c) and an annular peripheral upper erosion-protection portion formed of the polysilicon-oxide (107d). The annular polysilicon-oxide protection regions (107d) either reduce or entirely eliminate adverse sidewall parasitic erosion which occurs in conventional trench technology when processing active areas (124).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.