System and method of providing mask defect printability analysis
First Claim
1. A method of providing printability analysis for a defect on a physical mask, the method comprising:
- generating a simulated wafer image of the physical mask;
generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask;
identifying a first feature proximate to the defect on the simulated wafer image of the physical mask;
identifying a second feature on the simulated wafer image of the reference mask, the second feature corresponding to the first feature; and
computing critical dimension deviations including the first and second features to provide the printability analysis.
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Accused Products
Abstract
A simulated wafer image of a physical mask and a defect-free reference image are used to generate a severity score for each defect, thereby giving a customer meaningful information to accurately assess the consequences of using a mask or repairing that mask. The defect severity score is calculated based on a number of factors relating to the changes in critical dimensions of the neighbor features to the defect. A common process window can also be used to provide objective information regarding defect printability. Certain other aspects of the mask relating to mask quality, such as line edge roughness and contact corner rounding, can also be quantified by using the simulated wafer image of the physical mask.
144 Citations
54 Claims
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1. A method of providing printability analysis for a defect on a physical mask, the method comprising:
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generating a simulated wafer image of the physical mask;
generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask;
identifying a first feature proximate to the defect on the simulated wafer image of the physical mask;
identifying a second feature on the simulated wafer image of the reference mask, the second feature corresponding to the first feature; and
computing critical dimension deviations including the first and second features to provide the printability analysis. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of providing printability analysis for a defect on a physical mask, the method comprising:
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generating a simulated wafer image of the physical mask;
generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask;
identifying a first feature proximate to the defect on the simulated wafer image of the physical mask;
identifying a second feature on the simulated wafer image of the reference mask, the second feature corresponding to the first feature;
computing critical dimension deviations including the first and second features to provide the printability analysis;
identifying, a third defect-free feature on the simulated wafer image of the physical mask;
identifying a fourth feature on the simulated wafer image of the reference mask, the fourth feature corresponding to the third feature; and
computing critical dimension deviations including the third and fourth features. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method of providing printability analysis for a defect on a physical mask, the method comprising:
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generating a simulated wafer image of the physical mask;
generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask;
computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks;
computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and
using the average critical dimension deviation and the maximum critical dimension deviation to provide the printability analysis. - View Dependent Claims (14, 15, 16, 17)
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18. A method of providing printability analysis for a defect on a physical mask, the method comprising:
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generating a simulated wafer image of the physical mask;
identifying a first feature on the simulated wafer image affected by the defect;
identifying a second feature on the simulated wafer image unaffected by the defect, wherein the first and second features have substantially the same critical dimension in the absence of the defect;
computing a first critical dimension deviation for a defect-free area of the physical mask using the simulated water images of the physical and reference masks;
computing a second critical dimension deviation for a detect area of the physical mask using the simulated wafer images of the physical and reference masks; and
using the first and second critical dimension deviations to provide the printability analysis. - View Dependent Claims (19, 20, 21)
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22. A method of fabricating a physical mask, the method comprising:
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designing an integrated circuit;
creating mask design data for a layer of the integrated circuit;
manufacturing a physical mask conforming to the mask design data;
inspecting the physical mask based on a simulated wafer image of the physical mask and a simulated wafer image of a reference mask, wherein the reference mask corresponds to a defect-free physical mask, wherein inspecting comprises;
computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks;
computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and
using the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis; and
determining whether the physical mask passes inspection based on the printability analysis. - View Dependent Claims (23, 24, 25, 26, 27)
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28. A method of generating a defect severity score for a defect on a mask, the method comprising:
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providing two-dimensional analysis on the defect and a first feature on the mask, the first feature being proximate to the defect;
providing a first wafer image of the mask; and
providing defect analysis on a second feature on the wafer image, the second feature corresponding to the first feature being simulated, wherein providing defect analysis includes computing various critical dimension deviations based on the first and second features.
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29. A method of generating a defect severity score for a defect on a mask, the method comprising:
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providing two-dimensional analysis on the defect and a first feature on the mask, the first feature being proximate to the defect;
providing a first wafer image of the mask;
providing defect analysis on a second feature on the wafer image, the second feature corresponding to the first feature being simulated, wherein providing defect analysis includes computing various critical dimension deviations based on the first and second features;
identifying a third feature on a defect-free reference image of the mask, the third feature representing the first feature;
providing a second wafer image of the reference image, the second wafer image including a fourth feature, the fourth feature corresponding to the third feature being simulated; and
providing defect analysis on the fourth feature, wherein providing defect analysis includes computing various critical dimension deviations based on the first, second, third, and fourth features. - View Dependent Claims (30, 31, 32, 33, 34)
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35. A system for analyzing a defect on a physical mask, the system comprising:
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an inspection tool for generating a mask image from the physical mask and a reference image from a reference mask;
a wafer image generator for simulating a stepper mask image from the mask image and a stepper reference image from the reference image; and
a defect printability analysis generator for comparing the stepper mask image and the stepper reference image, wherein the defect printability analysis generator determines an average critical dimension deviation for a defect-free area on the physical mask using the stepper mask image and the stepper reference image, wherein the defect printability analysis generator determines a maximum critical dimension deviation for a defect area on the physical mask using the stepper mask image and the stepper reference image, and wherein the defect printability analysis generator uses the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis of the defect. - View Dependent Claims (36, 37, 38, 39, 40)
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41. A system for generating a defect severity score for a defect on a physical mask, the system comprising:
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means for generating a first image of a feature on the physical mask proximate to the defect and a second image of the feature on the reference image;
means for simulating a first wafer image of the first image and a second wafer image of the second image; and
means for generating the defect severity score based on the first and second wafer images, wherein the means for generating determines an average critical dimension deviation for a defect-free area on the physical mask using the first and second wafer images, wherein the means for generating determines a maximum critical dimension deviation for a defect area on the physical mask using the first and second wafer images, and wherein the means for generating uses the average critical dimension deviation and the maximum critical dimension deviation to provide the defect severity score. - View Dependent Claims (42, 43)
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44. An integrated circuit fabricated using a physical mask made by the following steps:
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generating a simulated wafer image of the physical mask;
generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask;
computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks;
computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks;
using the average critical dimension deviation and the maximum critical dimension deviation to determine whether to repair the physical mask; and
fabricating the integrated circuit using the physical mask.
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45. Computer software for analyzing a defect on a first mask, the software including:
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means for generating a simulated wafer image of the first mask;
means for generating a simulated wafer image of a second mask, the second mask corresponding to a defect-free first mask; and
means for computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks;
means for computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and
means for using the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis regarding the defect. - View Dependent Claims (46, 47, 48)
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49. A method of inspecting a physical mask, the physical mask including a defect, the method comprising the following steps:
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generating a simulated wafer image of the physical mask;
generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask;
computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks;
computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and
using the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis of the defect. - View Dependent Claims (50, 51, 52, 53, 54)
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Specification