Method for monitoring a reticle
US7300729B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 2006 |
| Grant date | Nov 27, 2007 |
| Priority date | — |
| Expiry date | Mar 29, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/146
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Reticles may comprise shading elements (SEs) for locally altering the reticle optical properties. However, such reticles may degrade over time as a result of repeated exposure to radiation in a lithography process, as the radiation may “heal” the SEs. Disclosed are techniques for monitoring a reticle in order to maintain confidence about the reticle's optical properties and the uniformity of patterns on wafers that are to be printed using the reticle. Reticles undergo periodic inspection comprising reticle transmission measurement and/or aerial imaging of the reticle. When such inspection indicates sufficient reticle degradation, the reticle is tagged for correction prior to its subsequent use in a lithography process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.