Device metrology targets and methods
US11054752B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 13, 2018 |
| Grant date | Jul 6, 2021 |
| Priority date | — |
| Expiry date | Jul 31, 2039 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D89/10
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An overlay metrology system includes one or more processors coupled to an illumination source to direct illumination to a sample and a detector to capture diffracted orders of radiation from the sample. The system may generate overlay sensitivity calibration parameters based on differential measurements of a calibration target including two overlay target cells on the sample, where first-layer target elements and second-layer target elements of the overlay target cells are distributed with a common pitch along a measurement direction and are misregistered with a selected offset value in opposite directions. The system may further determine overlay measurements based on differential measurements of additional overlay target cells with two wavelengths, where first-layer target elements and second-layer target elements of the additional overlay target cells are distributed with the common pitch and are formed to overlap symmetrically. The system may further adjust the overlay measurements with the overlay sensitivity calibration parameters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.