Undercut membrane mask for high energy photon patterning
First Claim
1. A mask for use with high energy radiation sources comprising:
- a substrate;
at least one dielectric layer formed on a first surface of said substrate to produce a layered structure having a thickness of a first dimension; and
at least one aperture in said layered structure, said aperture extending through said substrate, said aperture having a generally conically undercut edge profile with substantially vertical sidewalls of a second dimension adjacent to said first surface, said second dimension being substantially less than said first dimension for providing a thin object plane for said mask.
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Accused Products
Abstract
A mask for use with high energy radiation sources in precision projection processing by excimer lasers, for example, is described. The mask comprises a suitable substrate, such as silicon, upon which a multilayer dielectric stack is formed which acts as a reflective coating for the impinging excimer laser radiation, minimizing energy absorption by the mask substrate. The mask transparent areas are defined by the through-holes in the mask. The through-holes are formed with a conically undercut edge profile to define a thin object plane for the mask and minimize scattering of the radiation from the through-hole sidewalls. A method for fabricating the mask is also described.
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Citations
39 Claims
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1. A mask for use with high energy radiation sources comprising:
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a substrate; at least one dielectric layer formed on a first surface of said substrate to produce a layered structure having a thickness of a first dimension; and at least one aperture in said layered structure, said aperture extending through said substrate, said aperture having a generally conically undercut edge profile with substantially vertical sidewalls of a second dimension adjacent to said first surface, said second dimension being substantially less than said first dimension for providing a thin object plane for said mask. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for fabricating a mask for use with high energy radiation sources comprising the steps of:
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forming at a first surface of a planar substrate a doped layer, said doped layer having a higher concentration of dopant impurities to a first predetermined depth than the substrate beneath said doped layer; forming a first masking layer on said first surface and a second masking layer on a second surface opposite said first surface of said substrate, said first masking layer defining a desired mask pattern; forming at least one aperture through said second masking layer exposing selected portions of said second surface and etching said selected portions to form at least one recess in said substrate to a second predetermined depth, the substrate material remaining between said recess and said first surface forming a membrane; etching said membrane through said first masking layer to form a plurality of apertures in said desired mask pattern, said apertures extending through said membrane into said recess; anisotropic etching said membrane undercutting said heavily doped layer and forming outwardly sloping aperture sidewalls extending from said undercut layer to said recess defining a generally conical undercut edge profile for said apertures through said membrane; removing said first and second masking layers; and applying at least one dielectric layer to said first surface. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method of laser processing a target substrate comprising the steps of:
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generating a high energy radiation beam; locating a transmission mask defining a desired processing pattern in front of said target substrate, said high energy radiation beam incident on said transmission mask, said mask comprising; a substrate; at least one dielectric layer formed on a first surface of said substrate to produce a layered structure having a thickness of a first dimension, said high energy radiation beam incident on said dielectric layer; and at least one aperture in said layered structure, said aperture extending through said substrate and said dielectric layer, said aperture having a generally conically undercut edge profile with substantially vertical sidewalls of a second dimension adjacent to said first surface said second dimension being substantially less than said first dimension; and imaging the radiation transmitted through said mask exiting said undercut aperture onto said target substrate.
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31. A mask for use in laser processing of target materials comprising:
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a substrate; a reflective coating including at least one layer of dielectric material having a high reflectivity formed on a top surface of said substrate to produce a layered structure having a predetermined thickness; and at least one aperture in said layered structure, said aperture extending through said layered structure. - View Dependent Claims (38, 39)
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32. A mask for use in laser processing of target materials comprising:
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a substrate; at least one dielectric layer formed on a top surface of said substrate to produce a layered structure having a predetermined thickness; and at least one tub-shaped recess formed in a bottom surface of said substrate opposite said top surface for forming a membrane of said layered structure in the area of said recess, said membrane being of said predetermined thickness, a plurality of apertures formed in said membrane defining a desired pattern therein and extending through said membrane into said recess, each aperture having generally vertical sidewalls. - View Dependent Claims (33, 34, 35, 36, 37)
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Specification