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Photomask blank, photomask, and methods of manufacturing the same

  • US 8,021,806 B2
  • Filed: 06/29/2009
  • Issued: 09/20/2011
  • Est. Priority Date: 06/30/2008
  • Status: Expired due to Fees
First Claim
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1. A photomask blank for manufacturing a phase shift mask having a light-transmitting substrate provided with a phase shift part adapted to give a predetermined phase difference to transmitted exposure light,wherein the phase shift part is a dug-down part that is dug down from a surface of the light-transmitting substrate to a digging depth adapted to produce the predetermined phase difference with respect to exposure light transmitted through the light-transmitting substrate at a portion where the phase shift part is not provided,the photomask blank comprising:

  • an etching mask film, on the digging-side surface of the light-transmitting substrate, that is made of a material being dry-etchable with a chlorine-based gas, but not dry-etchable with a fluorine-based gas, and serves as an etching mask at least until the digging depth is reached when forming the dug-down part; and

    a light-shielding film, on an opposite-side surface of the light-transmitting substrate, that forms, by etching, a light-shielding part adapted to shield exposure light transmitted through the light-transmitting substrate in a region other than a transfer pattern region,wherein the light-shielding film comprises a portion that contacts with the opposite-side surface of the light-transmitting substrate and that is formed by a material having an etch resistance with respect to the light-transmitting substrate.

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