Deep trench bottle-shaped etching using Cl2 gas
US6306772A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Apr 19, 2000 |
| Grant date | Oct 23, 2001 |
| Priority date | — |
| Expiry date | Apr 19, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/3065
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method to fabricate bottle-shaped deep trench into a semiconductor substrate. After a neck profile is formed, the chlorine gas at a predetermined flow rate is added to the etching plasma gas composition, while the flow rates of the plasma gases are increased by about 30% by volume, to create an enlarged lower portion of the deep trench. Preferably, the neck portion is etched using an etching composition which contains HBr, NF.sub.3, and (He/O.sub.2) provided at flow rates of about 87:13:35 sccm. The enlarged lower portion is etched using an etching composition which contains HBr, NF.sub.3, and (He/O.sub.2) provided at flow rates of about 113.+-.12:17.+-.2:46.+-.5 sccm, and Cl.sub.2 provided at a flow rate between 10 and 40 sccm. It was found that the width of the lower portion of the deep trench can be increased by 100% with minimum side effects such as polymer deposition in the plasma chamber, which could occur as result of substantially increased flow rate of HBr and/or NF.sub.3.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.