Method for evaluating a local flare, correction method for a mask pattern, manufacturing method for a semiconductor device and a computer program product
First Claim
1. A method for evaluating a local flare in an exposure tool, comprising:
- measuring a projection light intensity distribution on a semiconductor substrate by transferring a monitor mask pattern of an inspection photomask onto the semiconductor substrate, the monitor mask pattern being a window pattern surrounded by an opaque film;
calculating a first ratio between an illumination light intensity at the monitor mask pattern and a first projection light intensity on the semiconductor substrate, the first projection light intensity calculated based on the monitor mask pattern;
calculating a distribution function of a local flare, due to a mask pattern coverage of the monitor mask pattern, based on the first ratio and the projection light intensity distribution;
dividing a design mask pattern of a target photomask into a plurality of unit areas;
calculating a second ratio between the illumination light intensity on each of the unit areas and a second projection light intensity on the semiconductor substrate, the second projection light intensity calculated based on the design mask pattern; and
calculating a local flare intensity in each of the unit areas, based on the second ratio and the distribution function.
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Accused Products
Abstract
A method for evaluating a local flare in an exposure tool, includes: measuring a projection light intensity distribution by transferring a monitor mask pattern onto a semiconductor substrate; calculating a first ratio between an illumination light intensity on the monitor mask pattern and a first projection light intensity calculated based on the monitor mask pattern; calculating a distribution function of a local flare, due to a mask pattern coverage of the monitor mask pattern, based on the first ratio and the projection light intensity distribution; dividing a design mask pattern into a plurality of unit areas; calculating a second ratio between the illumination light intensity on each of the unit areas and a second projection light intensity calculated based on the design mask pattern; and calculating a local flare intensity in each of the unit areas, based on the second ratio and the distribution function.
24 Citations
20 Claims
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1. A method for evaluating a local flare in an exposure tool, comprising:
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measuring a projection light intensity distribution on a semiconductor substrate by transferring a monitor mask pattern of an inspection photomask onto the semiconductor substrate, the monitor mask pattern being a window pattern surrounded by an opaque film;
calculating a first ratio between an illumination light intensity at the monitor mask pattern and a first projection light intensity on the semiconductor substrate, the first projection light intensity calculated based on the monitor mask pattern;
calculating a distribution function of a local flare, due to a mask pattern coverage of the monitor mask pattern, based on the first ratio and the projection light intensity distribution;
dividing a design mask pattern of a target photomask into a plurality of unit areas;
calculating a second ratio between the illumination light intensity on each of the unit areas and a second projection light intensity on the semiconductor substrate, the second projection light intensity calculated based on the design mask pattern; and
calculating a local flare intensity in each of the unit areas, based on the second ratio and the distribution function. - View Dependent Claims (2, 3, 4, 5)
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6. A method for evaluating a local flare in an exposure tool, comprising:
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projecting a first periodic mask pattern formed in an opaque film of an inspection photomask, onto a resist film on a semiconductor substrate;
projecting a second mask pattern including an opaque portion formed in the opaque film and an opening portion surrounding the opaque portion onto the resist film, so as to overlay the opaque portion onto a region of the resist film where the first mask pattern is projected;
forming a plurality of resist images corresponding to the periodic pattern;
measuring a line width distribution of the resist images in a repeating direction of the resist images; and
measuring a line width variation in an end portion of the resist images from an average value of the line widths in a center portion of the resist images, and a variation distance from the end portion to a position of the line width distribution reaching a variation tolerance of the line widths. - View Dependent Claims (7, 8, 9, 10)
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11. A correction method for a mask pattern, comprising:
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measuring a projection light intensity distribution of an exposure tool on a semiconductor substrate by transferring a monitor mask pattern of an inspection photomask onto the semiconductor substrate, the monitor mask pattern being a window pattern surrounded by an opaque film;
calculating a first ratio between an illumination light intensity at the monitor mask pattern and a first projection light intensity on the semiconductor substrate, the first projection light intensity calculated based on the monitor mask pattern;
calculating a distribution function of a local flare, due to a mask pattern coverage of the monitor mask pattern, based on the first ratio and the projection light intensity distribution;
dividing a design mask pattern of a target photomask into a plurality of unit areas;
calculating a second ratio between the illumination light intensity on each of the unit areas and a second projection light intensity on the semiconductor substrate, the second projection light intensity calculated based on the design mask pattern;
calculating a local flare intensity in each of the unit areas based on the second ratio and the distribution function; and
calculating a dimensional variation in a transferred resist pattern of the design mask pattern, based on a distribution of the local flare intensity on a surface of the semiconductor substrate. - View Dependent Claims (12, 13, 14, 15)
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16. A manufacturing method for a semiconductor device, comprising:
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measuring a projection light intensity distribution of an exposure tool on a semiconductor substrate by transferring a monitor mask pattern of an inspection photomask onto the semiconductor substrate, the monitor mask pattern being a window pattern surrounded by an opaque film;
calculating a first ratio between an illumination light intensity at the monitor mask pattern and a first projection light intensity on the semiconductor substrate, the first projection light intensity calculated based on the monitor mask pattern;
calculating a distribution function of a local flare, due to a mask pattern coverage of the monitor mask pattern, based on the first ratio and the projection light intensity distribution;
dividing a design mask pattern of a target photomask into a plurality of unit areas;
calculating a second ratio between the illumination light intensity on each of the unit areas and a second projection light intensity on the semiconductor substrate, the second projection light intensity calculated based on the design mask pattern;
calculating a local flare intensity in each of the unit areas, based on the second ratio and the distribution function;
calculating a dimensional variation in a transferred resist pattern of the design mask pattern, based on a distribution of the local flare intensity on a surface of the semiconductor substrate;
fabricating the target photomask using corrected mask pattern provided by correcting the design mask pattern based on the dimensional variation;
loading a semiconductor substrate coated with a resist film to the exposure tool;
projecting the target photomask onto the semiconductor substrate, so as to transfer the corrected mask pattern on the resist film, and to form a target resist pattern; and
processing the semiconductor substrate using the target resist pattern as a mask. - View Dependent Claims (17, 18)
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19. A manufacturing method for a semiconductor device, comprising:
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repeating processing for each of a plurality of exposure tools including;
projecting a first periodic mask pattern formed in an opaque film of an inspection photomask, onto a resist film on a semiconductor substrate;
projecting a second mask pattern including an opaque portion formed in the opaque film and an opening portion surrounding the opaque portion, onto the resist film, so as to overlay the opaque portion on a region of the resist film where the first mask pattern is projected;
forming a plurality of resist images corresponding to the periodic pattern;
measuring a line width distribution of the resist images in a repeating direction of the resist images; and
measuring a line width variation in an end portion of the resist images from an average value of the line widths in a center portion of the resist images, and a variation distance from the end portion to a position of the line width distribution reaching a variation tolerance of the line widths;
classifying the exposure tools based on the line width variation and the variation distance;
selecting a target exposure tool for a photolithography process from among the exposure tools; and
executing the photolithography process using the target exposure tool.
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20. A computer program product configured to be executed by a computer, comprising:
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an instruction to acquire a projection light intensity distribution on a semiconductor substrate measured by transferring a monitor mask pattern of an inspection photomask onto the semiconductor substrate, the monitor mask pattern being a window pattern surrounded by an opaque film;
an instruction to calculate a first ratio between an illumination light intensity at the monitor mask pattern and a first projection light intensity on the semiconductor substrate, the first projection light intensity calculated based on the monitor mask pattern;
an instruction to calculate a distribution function of a local flare, due to a mask pattern coverage of the monitor mask pattern, based on the first ratio and the projection light intensity distribution;
an instruction to divide a design mask pattern of a target photomask into a plurality of unit areas;
an instruction to calculate a second ratio between the illumination light intensity on each of the unit areas and a second projection light intensity on the semiconductor substrate, the second projection light intensity calculated based on the design mask pattern; and
an instruction to calculate a local flare intensity in each of the unit areas, based on the second ratio and the distribution function.
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Specification