Attenuated embedded phase shift photomask blanks
AssigneeInternational Business Machines Corporation
InventorsMarie Angelopoulos, Katherina Babich, S. Jay Chey, Michael Straight Hibbs, Robert N. Lang, Arpan Pravin Mahorowala, Kenneth Christopher Racette
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Abstract
An attenuating embedded phase shift photomask blank that produces a phase shift of the transmitted light is formed with an optically translucent film made of metal, silicon, nitrogen and oxygen. An etch stop layer is added to improve the etch selectivity of the phase shifting layer. A wide range of optical transmission (0.001% up to 15% at 157 nm) is obtained by this process.
Claims21
An attenuating phase shift mask blank for use in lithography comprising:
- substrate;
- an etch stop layer deposited on said substrate;
- a phase shifting layer disposed on said etch stop layer;
- and
- said phase shift mask blank being capable of producing a photomask with substantially 180° phase shift and an optical transmission of at least 0.001% at a selected wavelength of <500 nm.
A method of fabricating an attenuating phase shift mask blank for use in lithography comprising:
- providing a substrate;
- disposing a thin layer of etch stop layer on said substrate;
- disposing a layer of phase shifter layer on said substrate;
- said blank is capable of producing a photomask with 180° phase shift and an optical transmission of at least 0.001% at a selected wavelenth of <500 nm.
Dependencies are inferred from the claim text.