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US 11,143,973 B2Granted
Method for designing photomask
AssigneePowerchip Semiconductor Manufacturing Corporation
InventorsHsiao-Chiang Lin, Yu-Hsuan Chang, Li-Chun Tseng
Life of this patent
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Abstract
A method for designing a photomask includes calculating an open ratio of an initial photomask to determine whether the open ratio of the initial photomask is less than 25%, and then changing a design of the initial photomask in response to determining the open ratio is less than 25%, such that a changed photomask has a reverse tone to the design of the initial photomask, and an open ratio of the changed photomask is 75% or more. The method can solve the issue caused by thermal expansion of the photomask.
Claims6
A method for designing a photomask, comprising:
- calculating an open ratio of an initial photomask to determine whether the open ratio of the initial photomask is less than 25%;
- and
- in response to determining the open ratio is less than 25%, changing a design of the initial photomask, such that a changed photomask has a reverse tone to the design of the initial photomask, and an open ratio of the changed photomask is 75% or more.
Dependencies are inferred from the claim text.