Metrology method and apparatus, computer program and lithographic system
US10705437B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 9, 2018 |
| Grant date | Jul 7, 2020 |
| Priority date | — |
| Expiry date | Oct 9, 2038 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L23/544
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed is a method, and associated apparatuses, for measuring a parameter of interest relating to a structure having at least two layers. The method comprises illuminating the structure with measurement radiation and detecting scattered radiation having been scattered by said structure. The scattered radiation comprises normal and complementary higher diffraction orders. A scatterometry model which relates a scattered radiation parameter to at least a parameter of interest and an asymmetry model which relates the scattered radiation parameter to at least one asymmetry parameter are defined, the asymmetry parameter relating to one or more measurement system errors and/or an asymmetry in the target other than a misalignment between the two layers. A combination of the scatterometry model and asymmetry model is used to determine a system of equations, and the system of equations is then solved for the parameter of interest.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.