Is a
Patent attributes
Patent Jurisdiction
Patent Number
Patent Inventor Names
Masayuki Mogi0
Naoto Kondo0
Tsuneo Numanami0
Tsuneyuki Hagiwara0
Masayuki Nakatsu0
Date of Patent
March 18, 2008
0Patent Application Number
108969460
Date Filed
July 23, 2004
0Patent Primary Examiner
Patent abstract
A photomask blank substrate is made by polishing a starting substrate to a specific flatness in a principal surface region on a top surface of the substrate so as to form a polished intermediate product, then additionally polishing the intermediate product. Substrates made in this way exhibit a good surface flatness at the time of wafer exposure. When a photomask fabricated from a blank obtained from such a substrate is held on the mask stage of a wafer exposure system with a vacuum chuck, the substrate surface undergoes minimal warping, enabling exposure patterns of small geometry to be written onto wafers to good position and linewidth accuracies.
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