Method of making photomask blank substrates

Details Method of making photomask blank substrates Method of making photomask blank substrates

2004-07-23

2008-03-18

Rosasco, S. (Department: 1756)

Radiation imagery chemistry: process, composition, or product th

Radiation modifying product or process of making

Radiation mask

Reexamination Certificate

active

07344808

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.

REFERENCES:
patent: 6537844 (2003-03-01), Itoh
patent: 2004/0100624 (2004-05-01), Hagiwara et al.
patent: 2005/0019676 (2005-01-01), Nakatsu et al.
patent: 2005/0019677 (2005-01-01), Nakatsu et al.
patent: 2005/0019678 (2005-01-01), Nakatsu et al.
patent: 2003-50458 (2003-02-01), None

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