Phase shifting mask
US5342713A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 1992 |
| Grant date | Aug 30, 1994 |
| Priority date | — |
| Expiry date | Dec 18, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/30
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The present invention relates to a phase shifting mask for use in a photolithographic process of forming a wiring pattern. The phase shifting mask comprises a transparent base plate (11), shading layers (12) formed selectively on the transparent base plate (11), and two kinds of phase shifting layers (13a, 13b) formed on transparent portions of the transparent base plate between the adjacent shading layers, respectively. The phase difference of the two kinds of phase shifting layers (13a, 13b) relative to the transparent base plate (11) is 90.degree., and the phase difference between the phase shifting layers is 180.degree.. The transfer of an unnecessary pattern in the shifter edge portion can be obviated by using the shading layers having a phase difference of 90.degree. relative to the transparent base plate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.