Overlay key, method of forming the same, and method of measuring overlay accuracy
US10162273B2 · kind B2 · utility
6Cited by
7References
17Claims
0Family size
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Key dates
| Filing date | May 3, 2016 |
| Grant date | Dec 25, 2018 |
| Priority date | — |
| Expiry date | May 3, 2036 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70633
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Embodiments of the present disclosure disclose an overlay key including at least two overlay marks each having a first sub-mark and a second sub-mark centro-symmetrical to each other, the first sub-mark and the second sub-mark each including two bar patterns that are perpendicular to each other and have a common end. At least two of the overlay marks are located in different layers. Also disclosed is a method of forming the overlay key and a method of measuring overlay accuracy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.