Radiation imagery chemistry: process – composition – or product th – Radiation modifying product or process of making – Radiation mask
Patent
1980-01-14
1983-02-22
Bowers, Jr., Charles L.
Radiation imagery chemistry: process, composition, or product th
Radiation modifying product or process of making
Radiation mask
430 4, 430 15, 430 22, 430148, G03C 504, G03F 100
Patent
active
043749119
ABSTRACT:
A method of fabricating a photomask having at least three distinct zones of light transmissibility is disclosed. A first mask is made from a predetermined pattern, this mask having only two distinct zones of light transmissibility. A second mask, made by contact printing of a diazo film, is formed from a selected portion of one zone of the original pattern, which zone has the greater light transmissibility. The second mask, being a contact print, is the photographic opposite of the first. The two masks are then aligned with the selected portion of the second mask superimposed over its original location in the first mask and a composite latent image thereof is formed in a suitable emulsion. This composite image is then developed and fixed on an appropriate support to form a photomask having at least three density zones.
REFERENCES:
patent: 3202509 (1965-08-01), Drake et al.
patent: 3666463 (1972-05-01), Beynnon et al.
patent: 3674487 (1972-07-01), Druschel
patent: 3744904 (1973-07-01), Loprest et al.
patent: 3775119 (1973-11-01), Bemis
Habib, D. P., et al., "The Diazotype Process", Unconventional Photographic Systems, SPSE, 1964, pp. 113 and 126-133.
DeForest, W. S. "Photoresists", McGraw-Hill Book Co., 1975, pp. 151-153.
Bowers Jr. Charles L.
International Business Machines - Corporation
Seinberg Saul A.
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