Drift compensation for an optical metrology tool
US7428044B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 2006 |
| Grant date | Sep 23, 2008 |
| Priority date | — |
| Expiry date | Mar 17, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/93
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Drift in an optical metrology tool is compensated for by obtaining a first measured diffraction signal and a second measured diffraction signal of a first calibration structure mounted on the optical metrology tool. The first and second measured diffraction signals were measured using the optical metrology tool. The second measured diffraction signal was measured later in time than the first measured diffraction signal. A first drift function is generated based on the difference between the first and second measured diffraction signals. A third measured diffraction signal is obtained of a first structure formed on a first wafer using the optical metrology tool. A first adjusted diffraction signal is generated by adjusting the third measured diffraction signal using the first drift function.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.