Method of removing assist features utilized to improve process latitude
US6875545B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 27, 2002 |
| Grant date | Apr 5, 2005 |
| Priority date | — |
| Expiry date | Feb 26, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70466
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of transferring a lithographic pattern onto a substrate by use of a lithographic apparatus. The method includes the steps of: (1) defining features to be printed on the substrate; (2) determining which of the features require assist features to be disposed adjacent thereto in order for the features to be printed within defined resolution limits; (3) generating a mask containing the features to be printed and the assist features; (4) performing a first illumination process so as to print the features on the substrate, the first illumination process resulting in the partial printing of the assist features on the substrate; and (5) performing a second illumination process so as to reduce the amount of the assist features printed on the substrate; the second illumination process entails the step of performing a quadrapole illumination.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.