Variable-etch-depth gratings
US10976483B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 2020 |
| Grant date | Apr 13, 2021 |
| Priority date | — |
| Expiry date | Feb 24, 2040 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B2027/0178
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed herein are techniques for fabricating straight or slanted variable-etch-depth gratings. A photoresist material for fabricating a variable-etch-depth grating in a substrate is sensitive to light with a wavelength shorter than 300 nm and has an etch rate comparable to the etch rate of the substrate. A depth of an exposed portion of a photoresist material layer including the photoresist material correlates with the exposure dose. After exposure using a gray-scale mask and development, the photoresist material layer has a non-uniform thickness. The photoresist material layer with the non-uniform thickness and the underlying substrate are etched using a straight etching or slanted etching process to form the straight or slanted variable-etch-depth grating in the substrate. The variable-etch-depth grating is characterized by a non-uniform depth profile corresponding to the non-uniform thickness of the photoresist material layer before etching.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.