System, masks, and methods for photomasks optimized with approximate and accurate merit functions
US7703049B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 6, 2006 |
| Grant date | Apr 20, 2010 |
| Priority date | — |
| Expiry date | Apr 28, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P90/02
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Photomask patterns are represented using contours defined by mask functions. Given target pattern, contours are optimized such that defined photomask, when used in photolithographic process, prints wafer pattern faithful to target pattern. Optimization utilizes “merit function” for encoding aspects of photolithographic process, preferences relating to resulting pattern (e.g. restriction to rectilinear patterns), robustness against process variations, as well as restrictions imposed relating to practical and economic manufacturability of photomasks. An accurate, slower merit function may be used to determine adjustment parameters for a faster, approximate merit function. The faster merit function may be used for iteration and adjusted based on the adjustment parameters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.