Method of making a grayscale reticle using step-over lithography for shaping microlenses
AssigneeSharp Laboratories of America, Inc.
InventorsYoshi Ono, Bruce D. Ulrich, Wei Gao
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Abstract
A method of fabricating a grayscale reticle includes preparing a quartz wafer substrate; depositing a layer of SRO on the top surface of the quartz substrate; patterning and etching the SRO to form an initial microlens pattern using step-over lithography; patterning and etching the SRO to form a recessed pattern in the SRO; depositing an opaque film on the SRO; patterning and etching the opaque film; depositing and planarizing a planarizing layer; cutting the quartz wafer into rectangular pieces sized to be smaller than a selected blank reticle; bonding the a piece a to selected reticle blank to form a grayscale reticle; and using the grayscale reticle to form a microlens array on a photoimager.
Claims13
A method of fabricating a grayscale reticle, comprising:
- preparing a quartz wafer substrate;
- depositing a layer of SRO on the top surface of the quartz substrate;
- patterning and etching the SRO to form an initial microlens pattern using step-over lithography;
- patterning and etching the SRO to form a recessed pattern in the SRO;
- depositing an opaque film on the SRO;
- patterning and etching the opaque film;
- depositing and planarizing a planarizing layer, wherein the combination of the SRO and planarizing layer form a filmstack with a constant thickness;
- cutting the quartz wafer into rectangular pieces sized to be smaller than a selected blank reticle;
- bonding the pieces to selected reticle blanks to form a grayscale reticle.
A method of fabricating a grayscale reticle, comprising:
- preparing a quartz wafer substrate;
- depositing a layer of SRO on the top surface of the quartz substrate;
- patterning and etching the SRO to form an initial microlens pattern using step-over lithography;
- patterning and etching the SRO to remove a predetermined amount of SRO;
- depositing an opaque film of the SRO;
- patterning and etching the opaque film;
- depositing and planarizing a planarizing layer having a thickness equal to the predetermined amount of SRO removed, wherein the planarizing layer is formed of a material having a refractive index with a real part matching a refractive index with a real part of the SRO, and wherein the combination of the SRO and planarizing layer form a filmstack with a constant thickness;
- cutting the quartz wafer into pieces having a size smaller than that of a selected blank reticle;
- bonding the pieces to selected reticle blanks to form a grayscale reticle.
Dependencies are inferred from the claim text.