Exposure method using electron beam and substrate manufacturing method using the same
First Claim
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1. An exposure method comprising:
- providing a substrate having a layer of photoresist thereon;
designing a target pattern to be formed on the substrate;
creating a first dose map of first dose values, wherein the first dose values are representative of doses of energy of beams emitted by a light source of an exposure apparatus, and the first dose map includes a representation of a corrected version of the target pattern;
creating a second dose map of second dose values, different from the first dose values, wherein at least some of the second dose values correspond to values of doses of energy produced by overlapping ones of the beams;
controlling the light source of the exposure apparatus to irradiate respective regions of the layer of photoresist in such a way that said respective regions are exposed to doses of energy having values based on the second dose values to thereby alter said regions of the layer of photoresist; and
determining a cost function before or after obtaining the first dose map,wherein the cost function is converted into a minimum cost function by repeatedly calculating the first dose map and the second dose map, the second dose map calculated by the minimum cost function,wherein the cost function comprises a constraint term comprising input dose values of a first exposure pattern and minimum dose values given to a minimum line width of the first exposure pattern, andwherein the constraint term comprisesa first constraint term including a fixed input dose value which is provided to the first exposure pattern, anda second constraint term providing a second dose value corresponding to a minimum dose value at the minimum line width.
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Abstract
An exposure method includes designing a target pattern to be formed on a substrate, producing a first dose map having first dose values of beams of energy, e.g., electron beams, creating from the first dose map a second dose map having second dose values different from the first dose values, and irradiating regions of a layer of photoresist on the substrate with overlapping beams to expose the regions to doses of energy having values based on the second dose values. The photoresist layer may then be developed and used an etch mask. The etch mask may be used to etch a mask layer on a transparent substrate to form a reticle.
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Citations
18 Claims
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1. An exposure method comprising:
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providing a substrate having a layer of photoresist thereon; designing a target pattern to be formed on the substrate; creating a first dose map of first dose values, wherein the first dose values are representative of doses of energy of beams emitted by a light source of an exposure apparatus, and the first dose map includes a representation of a corrected version of the target pattern; creating a second dose map of second dose values, different from the first dose values, wherein at least some of the second dose values correspond to values of doses of energy produced by overlapping ones of the beams; controlling the light source of the exposure apparatus to irradiate respective regions of the layer of photoresist in such a way that said respective regions are exposed to doses of energy having values based on the second dose values to thereby alter said regions of the layer of photoresist; and determining a cost function before or after obtaining the first dose map, wherein the cost function is converted into a minimum cost function by repeatedly calculating the first dose map and the second dose map, the second dose map calculated by the minimum cost function, wherein the cost function comprises a constraint term comprising input dose values of a first exposure pattern and minimum dose values given to a minimum line width of the first exposure pattern, and wherein the constraint term comprises a first constraint term including a fixed input dose value which is provided to the first exposure pattern, and a second constraint term providing a second dose value corresponding to a minimum dose value at the minimum line width. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of manufacture comprising:
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forming a layer of photoresist on a substrate; exposing the photoresist to beams of energy emitted by a light source of an exposure apparatus; and developing the exposed photoresist to form a photoresist pattern, wherein exposing the photoresist comprises; designing a target pattern to be formed on the substrate; creating a first dose map of first dose values, wherein the first dose values are representative of doses of energy of individual ones of beams emitted by the light source of the exposure apparatus, and the first dose map includes a representation of a corrected version of the target pattern; creating a second dose map of second dose values, different from the first dose values, wherein at least some of the second dose values correspond to values of doses of energy produced by overlapping ones of the beams; controlling the light source of the exposure apparatus to irradiate respective regions of the layer of photoresist in such a way that said respective regions are exposed to doses of energy having values based on the second dose values, wherein the second dose map is representative of a second exposure pattern including unit cells to which the second values are assigned; and converting a mathematical representation of the second exposure pattern with a point spread function and using the converted mathematical representation of the second exposure pattern in irradiating the respective regions of the photoresist pattern. - View Dependent Claims (14, 15, 16, 17)
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18. A method of manufacturing a reticle, comprising:
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providing a transparent substrate having a mask layer thereon, and a layer of photoresist on the mask layer; exposing the layer of photoresist to beams of energy emitted by a light source of an exposure apparatus; developing the exposed photoresist to form a photoresist pattern; and etching the mask layer, using the photoresist pattern as an etch mask, to form a mask pattern on the substrate, wherein exposing the layer of photoresist includes; designing a target pattern to be formed on the substrate as the mask pattern; creating a first dose map of first dose values, wherein the first dose values are representative of doses of energy of individual ones of beams emitted by the light source of the exposure apparatus, and the first dose map includes a representation of a corrected version of the target pattern; creating a second dose map of second dose values, different from the first dose values, wherein at least some of the second dose values correspond to values of doses of energy produced by overlapping ones of the beams; and controlling the light source of the exposure apparatus to irradiate respective regions of the layer of photoresist in such a way that said respective regions are exposed to doses of energy having values based on the second dose values.
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Specification