Time-varying intensity map generation for reticles
US10401305B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 1, 2013 |
| Grant date | Sep 3, 2019 |
| Priority date | — |
| Expiry date | Mar 13, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/705
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical reticle inspection tool is used during a first inspection to obtain, for each set of one or more patch areas of the reticle, a reference average of multiple reference intensity values corresponding to light measured from sub-areas of each patch area. After using the reticle in photolithography processes, the optical reticle inspection tool is used during a second inspection to obtain, for each set of one or more patch areas, an average of multiple test intensity values corresponding to light measured from the sub-areas. The first and second inspections use the same tool setup recipe. A difference intensity map is generated, and such map comprises map values that each corresponds to a difference between each average of the test and reference intensity values for each set of one or more patches. The difference intensity map indicates whether the reticle has degraded over time more than a predefined level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.