METHOD OF DETERMINING A FLATNESS OF AN ELECTRONIC DEVICE...

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Reexamination Certificate

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C451S057000, C451S288000

Reexamination Certificate

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06951502

ABSTRACT:
A flatness of a substrate is determined to achieve a desired flatness of a mask blank by predicting the variation in flatness resulting from a film stress of a thin film formed on the substrate. The flatness is adjusted by measuring the flatness of the substrate as a measured flatness, selecting a load type with reference to the measured flatness, and polishing the substrate under pressure distribution specified by the load type. A principal surface of the substrate has a flatness greater than 0 μm and not greater than 0.25 μm. A polishing apparatus includes a rotatable surface table, a polishing pad formed thereon, abrasive supplying means for supplying an abrasive to the polishing pad, substrate holding means, and substrate pressing means for pressing the substrate. The substrate pressing means has a plurality of pressing members for individually and desirably pressing a plurality of divided regions of the substrate surface.

REFERENCES:
patent: 5951374 (1999-09-01), Kato et al.
patent: 6447368 (2002-09-01), Fruitman et al.
patent: 6468131 (2002-10-01), Korovin
patent: 6638140 (2003-10-01), Kimura et al.
patent: 6855908 (2005-02-01), Takeuchi et al.
patent: 2003/0104698 (2003-06-01), Taniguchi et al.
patent: 64-40267 (1989-02-01), None
patent: 2002-46059 (2002-02-01), None
patent: 2002-316835 (2002-10-01), None

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