Exposure mask, exposure mask substrate, method for fabricating the same, and method for forming pattern based on exposure mask
US5547787A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1993 |
| Grant date | Aug 20, 1996 |
| Priority date | — |
| Expiry date | Apr 21, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/26
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An exposure mask having an excellent alignment accuracy between patterns, which is prepared by first forming on a light transmissive substrate a light shielding film or a semi-transparent film pattern (first pattern) somewhat larger than a desired dimension, forming thereon a semi-transparent film or a light transmissive film pattern (second pattern) so as to include all patterns of the desired dimensions made up of a light shielding part, a semi-transparent part and a light transmissive part, and then removing a projected part of the first pattern with use of the second pattern as a mask. The semi-transparent film is formed of at least two layers each of which contains a common element, thus the semi-transparent film can be made with use of the same apparatus and when patterning, etching process can be carried out with use of the same etchant. Further, since in a mask including the semi-transparent pattern, at least that area of non-pattern zone where light reaches a wafer through the transfer, acts to shield the exposure light, too narrowed pattern or insufficient focal depth can be prevented.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.