Method of detecting degradation in photolithography processes based upon scatterometric measurements of grating structures, and a device comprising such structures
First Claim
1. A method, comprising:
- providing a wafer comprised of a plurality of grating structures, each of said grating structures being comprised of a plurality of features, each of said grating structures having a different critical dimension;
illuminating at least one of said plurality of grating structures;
measuring light reflected off of at least one of said grating structures to generate an optical characteristic trace for said at least one grating structure; and
determining the presence of residual photoresist material between said features of said at least one grating structure by comparing said generated optical characteristic trace to at least one optical characteristic trace from a library.
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Abstract
The present invention is generally directed to various methods of detecting degradation in photolithography processes based upon scatterometric measurements of grating structures, and a device comprising such structures. In one embodiment, the method comprises providing a wafer comprised of a plurality of grating structures, each of the grating structures being comprised of a plurality of features, each of the grating structures having a different critical dimension, illuminating at least one of the grating structures, measuring light reflected off of at least one of the grating structures to generate an optical characteristic trace for the grating structure, and determining the presence of residual photoresist material between the features of the grating structure by comparing the generated optical characteristic trace to at least one optical characteristic trace from a library. In some embodiments, the grating structures are arranged in a linear array. In one illustrative embodiment, the device comprises a wafer and a plurality of grating structures formed above the wafer, each of the grating structures having a different critical dimension, and at least one of the grating structures having a critical dimension that is less than an anticipated range of critical dimensions for integrated circuit devices to be formed on a wafer.
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Citations
46 Claims
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1. A method, comprising:
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providing a wafer comprised of a plurality of grating structures, each of said grating structures being comprised of a plurality of features, each of said grating structures having a different critical dimension;
illuminating at least one of said plurality of grating structures;
measuring light reflected off of at least one of said grating structures to generate an optical characteristic trace for said at least one grating structure; and
determining the presence of residual photoresist material between said features of said at least one grating structure by comparing said generated optical characteristic trace to at least one optical characteristic trace from a library. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method, comprising:
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providing a wafer comprised of a plurality of grating structures arranged in a linear array, each of said grating structures being comprised of a plurality of photoresist features, each of said grating structures having a different critical dimension;
illuminating at least one of said plurality of grating structures;
measuring light reflected off of at least one of said grating structures to generate an optical characteristic trace for said at least one grating structure; and
determining the presence of residual photoresist material between said features of said at least one grating structure by comparing said generated optical characteristic trace to at least one optical characteristic trace from a library. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method, comprising:
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providing a wafer comprised of a plurality of grating structures, each of said grating structures being comprised of a plurality of spaced-apart photoresist features, each of said grating structures having a different spacing between said photo-resist features, at least one of said grating structures having a spacing between said photoresist features that is less than an anticipated range of critical dimensions for integrated circuit devices to be formed on a wafer;
illuminating at least one of said plurality of grating structures;
measuring light reflected off of at least one of said grating structures to generate an optical characteristic trace for said at least one grating structure; and
determining the presence of residual photoresist material between said features of said at least one grating structure by comparing said generated optical characteristic trace to at least one optical characteristic trace from a library. - View Dependent Claims (18, 19, 20, 21, 22)
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23. A method, comprising:
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providing a wafer comprised of a plurality of grating structures arranged in a linear array, each of said grating structures being comprised of a plurality of features, each of said grating structures having a different critical dimension, at least one of said grating structures having a critical dimension that is less than an anticipated range of critical dimensions for integrated circuit devices to be formed on a wafer;
illuminating at least one of said plurality of grating structures;
measuring light reflected off of said at least one grating structure to generate an optical characteristic trace for said at least one grating structure; and
determining the presence of residual photoresist material between said features of said at least one grating structure by comparing said generated optical characteristic trace to at least one optical characteristic trace from a library. - View Dependent Claims (24, 25, 26, 27, 28)
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29. A device, comprising:
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a wafer; and
a plurality of grating structures formed above said wafer, each of said grating structures having a different critical dimension, at least one of said grating structures having a critical dimension that is less than an anticipated range of critical dimensions for integrated circuit devices to be formed on a wafer. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A device, comprising:
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a wafer; and
a plurality of grating structures formed above said wafer, each of said grating structures being comprised of a plurality of photoresist features, each of said grating structures having a different critical dimension, at least two of said grating structures having a critical dimension that is less than an anticipated range of critical dimensions for integrated circuit devices to be formed on a wafer. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46)
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Specification