Library accuracy enhancment and evaluation
US7617075B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 28, 2007 |
| Grant date | Nov 10, 2009 |
| Priority date | — |
| Expiry date | Nov 28, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70625
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The accuracy of a library of simulated-diffraction signals for use in optical metrology of a structure formed on a wafer is evaluated by utilizing an identity relationship inherent to simulated diffraction signals. Each simulated diffraction signal contains at least one set of four reflectivity parameters for a wavelength and/or angle of incidence. One of the four reflectivity parameters is selected. A value for the selected reflectivity parameter is determined using the identity relationship and values of the remaining three reflectivity parameters. The determined value for the selected reflectivity parameter is compared to the value in the obtained set of four reflectivity parameters to evaluate and improve the accuracy of the library. The identity relationship can also be used to reduce the data storage in a library.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.