Cutting patterns for full phase shifting masks
US6981240B2 · kind B2 · utility
4Cited by
48References
22Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 10, 2003 |
| Grant date | Dec 27, 2005 |
| Priority date | — |
| Expiry date | Sep 19, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/32139
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A full phase shifting mask (FPSM) can define substantially all of the features of an integrated circuit using pairs of shifters having opposite phase. In particular, cutting patterns for working with the polysilicon, or gate, layers and active layers of static random access memory (SRAM) cells are considered. To resolve phase conflicts between shifters, one or more cutting patterns can be selected. These cutting patterns include cuts on contact landing pads. This cut simplifies the FPSM layout while ensuring greater critical dimension control of the more important features and reducing mask misalignment sensitivity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.