Method for forming shallow trench isolation structure
US6001707A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 1, 1999 |
| Grant date | Dec 14, 1999 |
| Priority date | — |
| Expiry date | Feb 1, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76237
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for forming a shallow trench isolation structure in a substrate includes the steps of forming a doped region around the future top corner regions of a trench. The concentration of dopants inside the doped region increases towards the substrate surface. Thereafter, a trench is formed in the substrate, and then a thermal oxidation operation is carried out. Utilizing the higher oxidizing rate for doped substrate relative to an undoped region, the upper corners of the trench become rounded corners. Subsequently, a liner oxide layer is formed over the substrate surface inside the trench using conventional methods. Finally, insulating material is deposited into the trench to form a trench isolation structure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.