Method of designing phase grating pattern providing modified illumination optimum for producing a target pattern and method of manufacturing a photo mask system comprising the phase grating pattern
US6911286B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 9, 2003 |
| Grant date | Jun 28, 2005 |
| Priority date | — |
| Expiry date | Dec 25, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70158
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of designing a phase grating pattern provides a modified form of illumination for a main mask, optimum for producing one or more target patterns on a wafer in a photolithographic process. Once the target pattern(s) to be formed on the wafer are decided, an area to be occupied by at least a portion of the phase grating is divided into a plurality of subcells, initial phase values are assigned to each of the subcells, and one of the subcells is randomly selected and the phase value last assigned thereto is changed, and the process is repeated. The process is in an iteration that changes the arrangement of the phase values assigned to the subcells until they converge on one which will provide the design for a phase grating which will produce a modified form of illumination optimum for use in forming the target pattern(s) on the wafer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.