Process for improving the etch stability of ultra-thin photoresist
First Claim
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1. A method of increasing an etch stability of a photoresist layer, the method comprising the steps of:
- providing the photoresist layer at a thickness less than 0.25 μ
m, for use in vacuum ultraviolet lithography, deep ultraviolet lithography, or extreme ultraviolet lithography;
exposing the photoresist layer to a plasma, the photoresist layer including exposed surfaces; and
transforming the exposed surfaces to form a shell before using the photoresist layer to etch an underlying layer, wherein the shell increases the etch stability of the photoresist layer.
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Abstract
An integrated circuit fabrication process is disclosed herein. The process includes exposing a photoresist layer to a plasma, and transforming the top surface and the side surfaces of the photoresist layer to form a hardened surface. The process further includes etching the substrate in accordance with the transformed feature, wherein an etch stability of the feature is increased by the hardened surface. The photoresist layer is provided at a thickness less than 0.25 μm, for use in deep ultraviolet lithography, or for use in extreme ultraviolet lithography.
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Citations
23 Claims
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1. A method of increasing an etch stability of a photoresist layer, the method comprising the steps of:
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providing the photoresist layer at a thickness less than 0.25 μ
m, for use in vacuum ultraviolet lithography, deep ultraviolet lithography, or extreme ultraviolet lithography;
exposing the photoresist layer to a plasma, the photoresist layer including exposed surfaces; and
transforming the exposed surfaces to form a shell before using the photoresist layer to etch an underlying layer, wherein the shell increases the etch stability of the photoresist layer. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An integrated circuit fabrication process, the process comprising:
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patterning a feature on a photoresist layer disposed over a substrate, the feature patterned in accordance with a pattern provided on a mask or reticle and a radiation at a deep ultraviolet or extreme ultraviolet lithographic wavelength;
developing the photoresist layer, the patterned photoresist layer including at least one feature having a top surface and side surfaces;
exposing the photoresist layer to a fluorine-based plasma densifier;
transforming the top surface and the side surfaces with the densifier to form a hardened surface; and
etching the substrate in accordance with the transformed feature, wherein the exposing step occurs after the developing step and before the etching step, and an etch stability of the feature is a function of the hardened surface. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. An integrated circuit fabrication process, the process comprising:
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patterned a feature on a photoresist layer disposed over a substrate, the feature patterned in accordance with a pattern provide on a mask or reticle and a radiation at a deep ultraviolet or extreme ultraviolet lithographic wavelength;
developing the photoresist layer, the patterned photoresist layer including at least one feature having a top surface and side surfaces;
exposing the photoresist layer to a fluorine-based or argons densifier;
transforming the top surface and the side surfaces with the densifier to form a hardened surface; and
etching the substrate in accordance with the transformed feature, wherein the exposing step occurs after the developing step and before the etching step, and an etch stability of the feature is a function of the hardened surface, wherein the transforming step includes fluorinating the top surface and the side surfaces.
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16. A method of using a feature on a photoresist layer disposed above a layer or substrate, the feature including exposed surfaces, the feature being lithographically patterned using at least one of a deep ultraviolet lithographic wavelength, a vacuum ultraviolet lithographic wavelength, and an extreme ultraviolet lithographic wavelength or has a vertical thickness less than approximately 0.25 μ
- m, and the method comprising;
transforming the exposed surfaces to be structurally denser than the untreated region due to at least one of a fluorination, a fluorine ion implantation and argon ion implantation; and
etching or doping the layer or substrate according to the feature, wherein the exposed surfaces are structurally denser due to the fluorination, the fluorination including the feature being exposed to a fluorine-based plasma. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
- m, and the method comprising;
Specification