Image-based overlay targets incorporating features for pattern recognition and moire fringe patterns for measurement
US11748869B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 8, 2019 |
| Grant date | Sep 5, 2023 |
| Priority date | — |
| Expiry date | Jan 3, 2042 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2223/54426
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Embodiments disclosed herein include a lithography reticle set and methods of using such reticle sets. In an embodiment, the set comprises a first reticle and a second reticle. In an embodiment, the first reticle comprises a first grating having a first pitch, and a second grating having a second pitch. In an embodiment, the second reticle comprises a third grating having a third pitch, wherein the third pitch is different than the first pitch, and a fourth grating having a fourth pitch, wherein the fourth pitch is different than the first pitch. In an embodiment the third grating overlaps the first grating and the fourth grating overlaps the second grating when two or more edges of the first reticle are aligned with two or more edges of the second reticle. In an embodiment the first reticle or the second reticle further comprises a pattern recognition feature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.