Sub-wavelength segmentation in measurement targets on substrates
US9746785B2 · kind B2 · utility
3Cited by
5References
21Claims
0Family size
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Key dates
| Filing date | May 27, 2009 |
| Grant date | Aug 29, 2017 |
| Priority date | — |
| Expiry date | Feb 18, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Measurement targets for use on substrates, and overlay targets are presented. The targets include an array of first regions alternating with second regions, wherein the first regions include structures oriented in a first direction and the second regions include structures oriented in a direction different from the first direction. The effective refractive index of the two sets of regions are thereby different when experienced by a polarized beam, which will act as a TM-polarized beam when reflected from the first set of regions, but as a TE-polarized beam when reflected from the second set of regions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.