Three-phase phase shift mask
US6312855A · kind A · utility
1Cited by
1References
11Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 22, 1999 |
| Grant date | Nov 6, 2001 |
| Priority date | — |
| Expiry date | Nov 22, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/28
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A three-phase phase shift mask. On a transparent substrate, a non-transparent pattern covering a portion of the transparent substrate is formed, while the other portion of the substrate is remained exposed. A proximity region around a comer of the non-transparent pattern is equally partitioned three phase-shift areas different from each other with a phase shift of 120.degree.. The formation of these three phase-shift areas uses two etching steps to form a first and a second phase-shift areas, while a portion of the exposed substrate is etched twice as a third phase-shift area.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.