Dichromatic photomask and a method for its fabrication
US5501926A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1995 |
| Grant date | Mar 26, 1996 |
| Priority date | — |
| Expiry date | Jan 31, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/50
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of manufacturing a photomask for the production of dual depth features on substrates, and the photomask so manufactured, wherein the method of manufacturing the photomask is comprised of the steps of: (1) coating a substrate which transmits at least two selected wavelengths with: a) an optical filter material which prevents the transmission of at least one of the wavelengths, b) an opaque masking material, and c) a dual tone photoresist; (2) using a single mastering tool to selectively expose areas of the coated substrate to one of the wavelengths; (3) developing the photoresist; (4) etching the exposed masking material and optical filter material; (5) exposing the remaining coated substrate; (6) developing the remaining photoresist; (7) etching the exposed surface; and (8) stripping away the remaining photoresist.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.