Fast freeform source and mask co-optimization method
US8584056B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 2009 |
| Grant date | Nov 12, 2013 |
| Priority date | — |
| Expiry date | Jan 27, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F30/39
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The present invention relates to lithographic apparatuses and processes, and more particularly to tools for optimizing illumination sources and masks for use in lithographic apparatuses and processes. According to certain aspects, the present invention significantly speeds up the convergence of the optimization by allowing direct computation of gradient of the cost function. According to other aspects, the present invention allows for simultaneous optimization of both source and mask, thereby significantly speeding the overall convergence. According to still further aspects, the present invention allows for free-form optimization, without the constraints required by conventional optimization techniques.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.