Phase shift photomask, phase shift photomask blank, and process for fabricating them
US5702847A · kind A · utility
42Cited by
12References
23Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 30, 1995 |
| Grant date | Dec 30, 1997 |
| Priority date | — |
| Expiry date | May 30, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/32
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The invention relates to a phase shift photomask in which the peripheral region portion of a phase shift layer is removed by a relatively simple procedure and which has no or little defect and is inexpensive, a blank therefor, and a process for fabricating them. The process includes the steps of forming phase shift layer 23 all over the surface of one side of transparent substrate 21, and immersing only the peripheral region of substrate 21 in etching solution 25 to etch away the peripheral region of phase shift layer 23, whereby phase shift layer 27 is confined within an area smaller than that of substrate 21.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.