"Geometric autogeneration of""hard""phase-shift designs for VLSI"
US5636131A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 12, 1995 |
| Grant date | Jun 3, 1997 |
| Priority date | — |
| Expiry date | May 12, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S706/92
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An apparatus implemented in a computer aided design (CAD) system automatically generates phase shifted mask designs for very large scale integrated (VLSI) chips from existing circuit design data. The system uses a series of basic geometric operations to design areas requiring phase assignment, resolve conflicting phase assignments, and eliminate unwanted phase edges. This apparatus allows automatic generation of phase shift mask data from any circuit design that allows for phase shifting. Since the dimensional input for all geometric operations is directly linked to the design ground rules given to the circuit designers, any designable circuit layout can also be phase shifted with this algorithm. The autogeneration of phase shift patterns around an existing circuit design is broken down into four major tasks: 1. Define areas that need a phase assignment; 2. Make a first pass phase assignment unique to each critical feature and define "runs" of interrelated critical features; 3. Propagation phase assignment through the "runs"; and 4. Design trim features.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.