Lithography process optimization and system
First Claim
Patent Images
1. A method to optimize the optical transfer of a pattern onto photoresist using two or more exposure processes comprising:
- providing a photomask design to print a photoresist pattern with at least a first type pattern and a second type pattern;
determining a first exposure process using a first illumination condition that will improve at least a pattern fidelity parameter for the first type pattern;
said first illumination condition comprises a first aperture;
said first illumination condition is determined to improve at least said pattern fidelity parameter for said first type pattern transfer onto said photoresist;
determining a second exposure process using a second illumination condition that will improve at least the pattern fidelity parameter for the second type pattern;
said second illumination condition comprises a second aperture;
said second illumination condition is determined to improve at least said pattern fidelity parameter for said second type pattern transfer onto said photoresist from said photomask design;
then determining a first exposure dose for the first exposure process and a second exposure dose for the second exposure process that optimize the pattern fidelity parameter for the both the first type pattern and second type pattern type.
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Abstract
The first and second example embodiments are Pattern Fidelity Optimization Procedures for a Multiple Exposure Scheme. In the third example embodiment, the aperatures from the multiple exposure system can be combined into a single aperture by adding the apertures and modulating the relative transmission thru the respective apertures to match the prescribed dose split determined in above in the first embodiment.
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Citations
26 Claims
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1. A method to optimize the optical transfer of a pattern onto photoresist using two or more exposure processes comprising:
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providing a photomask design to print a photoresist pattern with at least a first type pattern and a second type pattern;
determining a first exposure process using a first illumination condition that will improve at least a pattern fidelity parameter for the first type pattern;
said first illumination condition comprises a first aperture;
said first illumination condition is determined to improve at least said pattern fidelity parameter for said first type pattern transfer onto said photoresist;
determining a second exposure process using a second illumination condition that will improve at least the pattern fidelity parameter for the second type pattern;
said second illumination condition comprises a second aperture;
said second illumination condition is determined to improve at least said pattern fidelity parameter for said second type pattern transfer onto said photoresist from said photomask design;
thendetermining a first exposure dose for the first exposure process and a second exposure dose for the second exposure process that optimize the pattern fidelity parameter for the both the first type pattern and second type pattern type. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method to optimize the optical transfer of a pattern onto photoresist using two or more exposure processes comprising:
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providing a photomask design to print a photoresist pattern with at least a first type pattern and a second type pattern;
the first type pattern and second type pattern are regions of features whose photoresist patterns can be improved by using different illumination conditions;
determining a first exposure process using a first illumination condition that will improve at least a pattern fidelity parameter for the first type pattern;
said first illumination condition comprises a first aperture;
said first illumination condition is determined to optimize at least a pattern fidelity parameter for said first type pattern transfer onto said photoresist;
determining a second exposure process using a second illumination condition that will improve at least the pattern fidelity parameter for the second type pattern;
said second illumination condition comprises a second aperture;
said first aperture and said second aperture have different configurations;
said second illumination condition is determined to optimize at least said pattern fidelity parameter for said second type pattern transfer onto said photoresist from said photomask design;
thendetermining a first exposure dose for the first exposure process and a second exposure dose for the second exposure process that optimize the pattern fidelity parameter for the both the first type pattern and second type pattern type;
said first dose is not is determined to optimize the pattern fidelity parameter for transfer of said type pattern onto said photoresist from the photomask;
said second dose is not determined to optimize the pattern fidelity parameter for transfer of said second type pattern onto said photoresist from the photomask.
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13. A photolithography process with two or more exposures, comprising:
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providing a wafer having a photoresist formed thereover;
providing a photomask with a first type pattern and a second type pattern formed therein aligned above said wafer;
the first type pattern and the second type pattern are regions whose photoresist patterns can be improved by using different illumination conditions;
performing a first exposure through said photomask at a first dose and with a first illuminating condition;
said first illumination condition is determined to optimize at least a pattern fidelity parameter for said first type pattern transfer onto said photoresist from said photomask;
said first dose is not is determined to optimize at least the pattern fidelity parameter for transfer of said first type pattern onto said photoresist from said photomask;
performing a second exposure through said photomask at a second dose and with a second illuminating condition;
said second illumination condition is determined to optimize said pattern fidelity parameter for said second type pattern transfer onto said photoresist from said photomask;
said second dose is not determined to optimize said pattern fidelity parameter for transfer of said second type pattern onto said photoresist from said photomask; and
the first and second illumination conditions are different;
the first dose and second dose are determined by optimizing at least said pattern fidelity parameter for the combination of the first type pattern and second type pattern transferred onto the photoresist;
developing said photoresist to form a photoresist pattern. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A method to make a composite aperture design for an optical transfer of a pattern onto photoresist using one exposure process comprising:
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providing a photomask design to print a photoresist pattern with at least a first type pattern and a second type pattern;
determining a first exposure process using a first illumination condition that will improve at a pattern fidelity parameter for the first type pattern;
said first illumination condition comprises a first aperture;
said first illumination condition is determined to optimize at least a pattern fidelity parameter for said first type pattern transfer onto said photoresist;
determining a second exposure process using a second illumination condition that will improve at least the pattern fidelity parameter for the second type pattern;
said second illumination condition comprises a second aperture;
said first aperture and said second aperture have different configurations;
said second illumination condition is determined to optimize at least said pattern fidelity parameter for said second type pattern transfer onto said photoresist from said photomask design;
thendetermining a first exposure dose for the first exposure process and a second exposure dose for the second exposure process that optimize the pattern fidelity parameter for the both the first type pattern and second type pattern type;
making a composite aperture design by combining the first aperture and second apertures to form a composite aperture design;
designing a modulating means for modulating the relative transmission through the first aperture and second aperture to allow the first exposure dose and second exposure dose through the first and second apertures of the composite aperture design. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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Specification