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Photomask and methods for manufacturing and correcting photomask

  • US 8,974,987 B2
  • Filed: 02/04/2010
  • Issued: 03/10/2015
  • Est. Priority Date: 02/16/2009
  • Status: Active Grant
First Claim
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1. A halftone phase shifting mask using an ArF excimer laser as an exposing source, being used for a projection exposure by an off axis illumination, and comprising on a principal plane of a transparent substrate a main pattern transferred to a transfer-target surface by the projection exposure and an assist pattern formed nearby the main pattern, where the assist pattern is not transferred to the transfer-target surface and a minimum pattern pitch of the main pattern on the transfer-target surface is a pitch of 120 nm or less;

  • wherein the main pattern and the assist pattern are each constituted from a semi-transparent film made of a same material; and

    a first retardation of 180°

    is generated between a first light transmitting through the main pattern and a second light transmitting through a transparent region of the transparent substrate, and a predetermined second retardation within a scope of 70°

    to 115°

    is generated between a third light transmitting through the assist pattern and the second light transmitting through the transparent region of the transparent substrate.

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