Removing process-variation-related inaccuracies from scatterometry measurements
US9874527B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 2015 |
| Grant date | Jan 23, 2018 |
| Priority date | — |
| Expiry date | Jan 9, 2036 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70633
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Metrology methods and respective software and module are provided, which identify and remove measurement inaccuracy which results from process variation leading to target asymmetries. The methods comprise identifying an inaccuracy contribution of process variation source(s) to a measured scatterometry signal (e.g., overlay) by measuring the signal across a range of measurement parameter(s) (e.g., wavelength, angle) and targets, and extracting a measurement variability over the range which is indicative of the inaccuracy contribution. The method may further assume certain functional dependencies of the resulting inaccuracy on the target asymmetry, estimate relative donations of different process variation sources and apply external calibration to further enhance the measurement accuracy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.