Method for fabricating photomasks having a phase shift layer comprising the use of a positive to negative resist, substrate imaging and heating
US5380609A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1993 |
| Grant date | Jan 10, 1995 |
| Priority date | — |
| Expiry date | Jul 29, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/30
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The invention relates to a method for forming a resist pattern for dry etching a phase shifter layer in which a phase shifter pattern portion and a portion for protecting the surface of a light-blocking pattern are formed by a single photolithographic step. A light-blocking patter 40 is formed on a phase shifter layer 33, followed by the formation of a positive to negative image reversible resist thin film 41. A given region of the resist thin film 41 that includes a part of the unpatterned region thereof is exposed to ionizing radiation 42. Post-exposure baking for image reversal is carried out. Subsequently, the whole back side of the substrate is exposed to ultraviolet light 44 using the light-blocking pattern as a mask, thereby enabling only an unexposed region of the unpatterned resist to be soluble in a developer. The resist thin film 41 is developed to form a resist pattern 45.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.