摘要 |
A subject pattern and a lower layer pattern are divided into small regions of a constant dimension using identical mesh of division. Considering of the spreading of charged particle beam due to backward scattering, the small region is set to be, for example, a few mu m square. An irradiation energy on each small region is determined by taking backward scattering from lower level pattern into account. Calculation is simplified because a pattern is represented by a pattern areal density. A region with a lower level pattern and a region without a lower level pattern can be exposured by charged particle beam with a comparable accuracy. |