Method of making a rim-type phase-shift mask
First Claim
1. A method of forming a rim-type phase-shift mask designed for use in a phase-shift lithography process, the method comprising the steps of:
- (a) providing a substrate having opposing first and second surfaces, said substrate being made from a material through which electromagnetic radiation of a predetermined frequency range may be transmitted, said first surface being at least partially covered with a first layer of material that substantially blocks the transmission therethrough of electromagnetic radiation of said predetermined frequency range;
(b) forming a plurality of openings extending through said first layer so as to expose underlying portions of said substrate;
(c) depositing a layer of resist on said first layer; and
(d) exposing said second surface of said substrate to electromagnetic radiation having a frequency range in said predetermined frequency range for a period of time sufficient to permit said electromagnetic radiation to propagate through said substrate and activate those portions of said layer of resist on said first layer extending from peripheral edges of said first layer inwardly a distance of at least about 0.05 micron, as measured along an axis extending parallel to said first surface of said substrate.
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Abstract
A method of forming rim type phase-shift lithography mask (140) involving backside overexposure of a positive resist layer (130) overlying a patterned light-blocking layer (120). By subjecting the resist layer to electromagnetic radiation (132) (e.g., broad band UV) transmitted via the backside (115) of the mask substrate (112), portions (134) of the resist layer extending from peripheral edges of the light blocking layer inwardly a selected distance are activated. After developing activated portions of the resist layer, the "pull back" of the resist layer is transferred to the underlying light blocking layer by anisotropically etching portions of the light blocking layer not covered by the resist layer, thereby forming the desired rim structure.
21 Citations
16 Claims
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1. A method of forming a rim-type phase-shift mask designed for use in a phase-shift lithography process, the method comprising the steps of:
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(a) providing a substrate having opposing first and second surfaces, said substrate being made from a material through which electromagnetic radiation of a predetermined frequency range may be transmitted, said first surface being at least partially covered with a first layer of material that substantially blocks the transmission therethrough of electromagnetic radiation of said predetermined frequency range; (b) forming a plurality of openings extending through said first layer so as to expose underlying portions of said substrate; (c) depositing a layer of resist on said first layer; and (d) exposing said second surface of said substrate to electromagnetic radiation having a frequency range in said predetermined frequency range for a period of time sufficient to permit said electromagnetic radiation to propagate through said substrate and activate those portions of said layer of resist on said first layer extending from peripheral edges of said first layer inwardly a distance of at least about 0.05 micron, as measured along an axis extending parallel to said first surface of said substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of forming a rim-type phase-shift mask designed for use in a phase-shift lithography process, the method comprising the steps of:
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(a) providing a substrate having opposing first and second surfaces, said substrate being made from a material through which electromagnetic radiation of a predetermined frequency range may be transmitted, said first surface being at least partially covered with a first layer of material that substantially blocks the transmission therethrough of electromagnetic radiation of said predetermined frequency range; (b) forming a plurality of openings in said first layer so as to expose portions of said substrate; (c) depositing a layer of resist on said first layer and on portions of said substrate exposed through said openings in said first layer; (d) transmitting electromagnetic radiation having a frequency range in said predetermined frequency range through said substrate via its second surface for a selected period of time so as to cause said electromagnetic radiation to activate portions of said resist layer, wherein said selected period of time is longer than is required to activate those portions of said layer of resist not covering said first layer; (e) developing said layer of resist for at least a period of time sufficient to remove portions of said layer of resist activated by said electromagnetic radiation; and (f) removing those portions of said first layer not covered by said layer of resist remaining after said step (e) is completed using an anisotropic etching process. - View Dependent Claims (10, 11)
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12. A method of forming a self-aligned rim structure on a substrate, the method comprising the steps of:
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(a) providing a substrate having opposing first and second surfaces, said substrate being made from a material through which electromagnetic radiation of a predetermined frequency range may be transmitted, said first surface being at least partially covered with a first layer of material that substantially blocks the transmission therethrough of electromagnetic radiation of said predetermined frequency range; (b) forming a plurality of openings extending through said first layer so as to expose underlying portions of said substrate; (c) depositing a layer of resist on said first layer and on portions of said substrate exposed through said openings in said first layer; and (d) removing those portions of said layer of resist (i) on said portions of said substrate exposed through said openings in said first layer and (ii) on said first layer extending from peripheral edges of said first layer inwardly a distance of at least about 0.05 micron, as measured along an axis extending parallel to said first surface of said substrate. - View Dependent Claims (13, 14, 15, 16)
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Specification