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Imaging Hard Surface Photomask Blanks Using White Light Actinic Radiation

IP.com Disclosure Number: IPCOM000040646D
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Betteridge, BL: AUTHOR [+3]

Abstract

A hard surface photomask blank typically consists of a glass base coated with a thin film (.1000 Ao) of metal, metallic oxide, or semiconductor. Typical thin film coatings include chromium, iron oxide, and silicon. In order to image a hard surface photomask blank, it is coated with a photosensitive material and selectively exposed to the required actinic radiation. The photosensitive coating is then subjected to a developing solution which removes the exposed areas of the photosensitive coating, thereby leaving the underlying thin film coating unprotected from contact with etchant solutions. These unprotected areas of the thin film are then removed by subjecting the blank to the appropriate etchant. Finally, the remaining photosensitive coating is stripped to yield the finished photomask.

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Imaging Hard Surface Photomask Blanks Using White Light Actinic Radiation

A hard surface photomask blank typically consists of a glass base coated with a thin film (.1000 Ao) of metal, metallic oxide, or semiconductor. Typical thin film coatings include chromium, iron oxide, and silicon. In order to image a hard surface photomask blank, it is coated with a photosensitive material and selectively exposed to the required actinic radiation. The photosensitive coating is then subjected to a developing solution which removes the exposed areas of the photosensitive coating, thereby leaving the underlying thin film coating unprotected from contact with etchant solutions. These unprotected areas of the thin film are then removed by subjecting the blank to the appropriate etchant. Finally, the remaining photosensitive coating is stripped to yield the finished photomask. The photosensitive coating which is currently in general use to image hard surface photomask blanks is photoresist, which requires ultraviolet radiation exposure for sensitization. In the following described process, a photographic emulsion coating replaces the photoresist coating. The photographic emulsion coating is selectively exposed to white light and processed in standard photographic chemicals. After performing an etch bleach reversal process on the developed emulsion, the thin film is then etched in a plasma environment, thereby eliminating the need for hazardous acid etch baths. The remaining emul...