Grating-over-grating overlay measurement with parallel color per layer
US12399435B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 20, 2023 |
| Grant date | Aug 26, 2025 |
| Priority date | — |
| Expiry date | Mar 1, 2044 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70633
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An overlay metrology system may include an illumination source to generate illumination including two or more spectral bands having two or more center wavelengths. The system may include an optical sub-system to illuminate and image a sample, where the sample in accordance with the metrology recipe includes one or more cells with grating-over-grating structures formed as overlapping gratings with different pitches in different sample layers. The system may include collection pupil components to exclusively pass, for each of the two or more center wavelengths, two diffraction lobes from each of the different pitches of the grating-over-grating structures. A controller may receive images of the sample from the detectors generated in accordance with the metrology recipe and generate overlay measurements between at least some of the different layers of the sample based on the images.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.