Photomask, microstructure, manufacturing method of photomask, and aligner
US6866969B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 2002 |
| Grant date | Mar 15, 2005 |
| Priority date | — |
| Expiry date | Mar 28, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/001
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Provided is a photomask enabling accurate tone representation. This photomask has a transparent substrate (42), and a phase grating structured from a plurality of grooves of a fixed pitch (P) formed on said substrate, wherein at least either the depth or width of the respective grooves of the phase grating is made to bear the exposure pattern. And, when the wavelength of the exposed light of the aligner employing the photomask is set to λ, and the incident side numerical aperture of the imaging system lens is set to NAi, P<λ/NAi. Thereby, the grating will no longer be imaged, and the exposure pattern represented with the depth or width of the respective grooves of the phase grating will be transcribed on to a light sensitive material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.