Shallow trench isolation formation with simplified reverse planarization mask
US6124183A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 1997 |
| Grant date | Sep 26, 2000 |
| Priority date | — |
| Expiry date | Dec 18, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76224
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An insulated trench isolation structure with large and small trenches of differing widths is formed in a semiconductor substrate using a simplified reverse source/drain planarization mask. Embodiments include forming trenches and refilling them with an insulating material which also covers a main surface of the substrate, polishing to remove an upper portion of the insulating material and to planarize the insulating material above the small trenches, furnace annealing to densify and strengthen the remaining insulating material, masking the insulating material above the large trenches, isotropically etching the insulating material, and polishing to planarize the insulating material. Since the insulating material is partially planarized and strengthened prior to etching, etching can be carried out after the formation of a relatively simple planarization mask over only the large trenches, and not the small trenches. Because the features of the planarization mask are relatively few and have a relatively large geometry, the present invention avoids the need to create and implement a critical mask, enabling production costs to be reduced and manufacturing throughput to be increased.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.