Character pattern extracting method, charged particle beam drawing method, and character pattern extracting program

A charged particle beam drawing method comprising:

• ranking character patterns the number of which is larger than a maximum number of character patterns which are formed in an aperture depending on the number of times of reference in design data of a semiconductor device;
• extracting a plurality of first extraction patterns the number of which is smaller than the maximum number from the larger number of character patterns in a descending order of the number of times of reference;
• defining a plurality of character patterns except the first extraction patterns out of the larger number of character patterns as candidate patterns;
• selecting from the plurality of candidate patterns a plurality of candidate patterns the number of which corresponds to a difference obtained by subtracting the number of extracted patterns from the maximum number, and creating a plurality of combinations of the plurality of selected candidate patterns;
• extracting a plurality of second extraction patterns included in a combination among the plurality of combinations of the selected candidate patterns, in which a manufacturing time of the semiconductor device is most shortened;
• manufacturing an aperture having the first extraction patterns and the second extraction patterns;
• and
• irradiating a charged particle beam on a resist film by using the aperture.

A non-transitory computer readable medium encoded thereon a character pattern extracting program which causes the computer to execute:

• ranking character patterns the number of which is larger than a maximum number of character patterns which are formed in an aperture depending on the number of times of reference in design data of a semiconductor device;
• extracting a plurality of first extraction patterns the number of which is smaller than the maximum number from the larger number of character patterns in a descending order of the number of times of reference;
• defining a plurality of character patterns except the first extraction patterns out of the larger number of character patterns as candidate patterns;
• selecting from the plurality of candidate patterns a plurality of candidate patterns the number of which corresponds to a difference obtained by subtracting the number of extracted patterns from the maximum number, and creating a plurality of combinations of the plurality of selected candidate patterns;
• and extracting a plurality of second extraction patterns included in a combination among the plurality of combinations of the selected candidate pattern, in which a manufacturing time of the semiconductor device is most shortened.