PROGRAMMED PRODUCTION OF MASK ROM

摘要

PROBLEM TO BE SOLVED: To increase a pattern forming parameter area by obtaining a sufficiently flat program code through use of a specified principle. SOLUTION: A link group of decode B of the program code A of a mask A40 is obtained and then program code C is obtained. Furthermore, the program code A is linked with the inversion code B' of decode B to obtain program code D. Decode B is a program code where 0 and 1 are mixed. The program codes C and D are divided, respectively, into masks C60 and D70 which are then exposed twice independently thus obtaining results similar to those obtained by using the mask A40 independently. Since the program code A is linked into groups, two sets of sufficiently uniform program code are obtained and the pattern forming parameter area can be increased.