Contacting and filling deep-trench-isolation with tungsten
US8294203B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 2, 2005 |
| Grant date | Oct 23, 2012 |
| Priority date | — |
| Expiry date | Jun 20, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/763
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Electrically isolated, deep trench isolation (DTI) structures, are formed in a wafer, and a portion of the DTI structures are converted to electrically connected structures to provide a shielding function, or to provide connection to deep buried layers. In one aspect, DTI structures include a polysilicon filling over a liner layer disposed on the inner surface of a deep trench, the polysilicon is removed by isotropic etching, and the deep trench is re-filled with a conductive material. Alternatively, the polysilicon filling remains and a contact is formed to provide an electrical connection to the polysilicon. In another aspect, a deep trench is disposed in the wafer such that a lower portion thereof is located within a deep buried layer, and after the polysilicon is removed, an anisotropic etch removes a portion of the deep trench liner from the bottom of the deep trench, thereby allowing a tungsten deposition to make electrical contact with the deep buried layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.