Determining transmittance of a photomask using optical metrology
US7639375B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 14, 2006 |
| Grant date | Dec 29, 2009 |
| Priority date | — |
| Expiry date | Jun 25, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30148
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Transmittance of a photomask is determined using optical metrology. In particular, reflectance of a portion of the photomask is determined by directing an incident beam of light at the portion of the photomask. The reflectance is determined by measuring light diffracted from the portion of the photomask. One or more geometric features of the portion of the photomask are determined using the measured light diffracted from the portion of the photomask. A wave coupling is determined using the determined one or more geometric features of the portion of the photomask. The transmittance of the photomask is determined using the determined wave coupling and the determined reflectance of the portion of the photomask.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.