Patent ID: 7594216

Claim:
A method of forming a mask pattern on data, comprising: preparing a second cell library by making process proximity effect correction with respect to cell patterns stored in a first cell library, the second cell library storing corrected cell patterns, the cell patterns each being a cell pattern area which includes pattern regions for realizing individual circuit characteristics and no-pattern regions where no patterns are formed; placing a first corrected cell pattern and a second corrected cell pattern of the corrected cell patterns so that an edge of the first corrected cell pattern and an edge of the second corrected cell pattern contact or come close to or overlap each other; extracting a boundary pattern at the boundary neighborhood between the first corrected cell pattern and the second corrected cell pattern; and making process proximity effect correction with respect to the boundary pattern, wherein said preparing a second cell library includes: forming a provisional cell pattern by placing outside and off the cell pattern area a dummy pattern that has a proximity effect on the cell pattern; making process proximity effect correction with respect to the provisional cell pattern to form a corrected provisional cell pattern; and removing the whole dummy pattern from the corrected provisional cell pattern.