OPTICAL PROXIMITY EFFECT CORRECTING METHOD AND MASK DATA FORMING METHOD IN SEMICONDUCTOR MANUFACTURING PROCESS, WHICH CAN SUFFICIENTLY CORRECT OPTICAL PROXIMITY EFFECT, EVEN UNDER VARIOUS SITUATIONS WITH REGARD TO SIZE AND SHAPE OF DESIGN PATTERN, AND SPACE WIDTH AND POSITION RELATION BETWEEN DESIGN PATTERNS

An optical proximity effect correcting method in a semiconductor manufacturing process includes adding, detecting, judging, and deleting. The adding includes adding a first correcting region around a portion of a first design pattern. The portion faces a second design pattern. A first corrected design pattern includes the first correcting region and the first design pattern. The detecting includes detecting a space between the first corrected design pattern and the second design pattern. The judging includes judging whether the space is smaller than or equal to a predetermined value. The deleting includes deleting at least a portion of the first correcting region such that the space is larger than the predetermined value, when the space is smaller than or equal to the predetermined value.