Opposite focus control to avoid keyholes inside a passivation layer
US6159660A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 1997 |
| Grant date | Dec 12, 2000 |
| Priority date | — |
| Expiry date | Feb 3, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/32139
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of forming a number of closely spaced electrodes is described wherein covering the electrodes with a conformal layer of oxide or nitride deposited using plasma enhanced chemical vapor deposition does not result in the formation of restricted regions or keyholes between adjacent electrodes. The method uses de-focussing to form the electrode mask pattern in a layer of photoresist. The focal plane in which the electrode pattern is focussed is positioned a de-focus distance above the layer of photoresist. The de-focus method results in electrodes having a trapezoidal cross section wherein the bottom of the electrode is wider than the top of the electrode. The trapezoidal cross section avoids the formation of restricted regions or keyholes when the electrodes are covered with a conformal dielectric layer, such as a layer of oxide or nitride deposited using plasma enhanced chemical vapor deposition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.