Method for manufacturing a pair of complementary masks
AssigneeNEC Corporation
InventorsYasuhisa Yamada, Kenichi Takada
Life of this patent
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Abstract
A method for manufacturing a pair of complementary masks for use in an electron projection lithographic (EPL) technique uses an algorithm for distributing the design data to a pair of EPL masks. The algorithm allocates a positive sign or negative sign to each of the pattern data, summation of the areas of the pattern data having positive signs while subtracting the areas of the pattern data having negative signs, for obtaining a minimum of the sum. One or more of initial combination of the signs is prepared and the vicinity of the initial combination is calculated therefrom for obtaining an optimum combination.
Claims6
A method for manufacturing a pair of complementary masks comprising the steps of extracting a plurality of pattern data from design data, distributing said pattern data to a pair of complementary mask data, and forming a pair of complementary masks based on said complementary mask data, said distributing step including the steps of;
- allocating either a first or a second sign to each of said pattern data to obtain an initial combination of signs;
- changing said sign of one or more element of initial combination to obtain a next combination, and calculating a sum data for said next combination by adding areas of said pattern data each having said first sign in said next combination while subtracting areas of said pattern data each having said second sign in said next combination;
- iterating said changing of said sign and said calculating of a sum data for said next combination, to obtain an optimum combination of said first and second signs providing a minimum of said sum data;
- and
- assigning said pattern data having first signs to one of said complementary mask data, and said pattern having said second signs to the other of said complementary mask data.
Dependencies are inferred from the claim text.