Manufacture of trench-gate semiconductor devices
US6518129B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 17, 2001 |
| Grant date | Feb 11, 2003 |
| Priority date | — |
| Expiry date | Aug 17, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D30/025
Abstract
The manufacture of a trench-gate semiconductor device, for example a power transistor or a memory device includes the steps of forming at a surface (10a) of a semiconductor body (10) a first mask (51) having a first window (51a), providing a thin layer of a second material (52) in the first window (51a), forming an intermediate mask (53A, 53B) of a third material having curved sidewalls and using the intermediate mask (53A, 53B) to form two L-shaped parts (52A, 52D and 52B, 52E) of the second material with a second window (52a) which is used to etch a trench-gate trench (20). The rectangular base portion (52D, 52E) of each L-shaped part ensures that the trench (20) is maintained narrow during etching. Narrow trenches are advantageous for low specific on-resistance and low RC delay in low voltage cellular trench-gate power transistors. Narrow deep trenches are also advantageous for cell density in DRAM devices where a memory cell has a switching transistor cell surrounded by a trench-gate and a storage capacitor in a lower part of the same trench.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.