Multi charged particle beam writing apparatus, and multi charged particle beam writing method

A multi charged particle beam writing apparatus comprising:

• an irradiation time calculation circuit configured to calculate an irradiation time of a beam to each pixel, for the each pixel of a plurality of pixels which are obtained by dividing a writing region of a target object and each of which serves as an irradiation unit region per beam of multi charged particle beams;
• a gray-scale value calculation circuit configured to calculate, for the each pixel, a gray-scale value of gradation by gray scale levels by dividing the irradiation time by a quantization unit;
• a gray-scale value correction circuit configured to correct, for each group of a plurality of groups each composed of adjacent pixels, dose errors each caused by the gradation, by gray scale levels, of the irradiation time, said dose errors occurring in the adjacent pixels having the gray-scale value of finite value in a group concerned in the plurality of groups, by performing one of increasing and decreasing the gray-scale value of at least one pixel of the adjacent pixels having the gray-scale value of finite value in the group concerned by 1;
• and
• a writing mechanism configured to include a shaping aperture array substrate which forms the multi charged particle beams, a deflector which deflects the multi charged particle beams, and a stage on which the target object is placed, and to write a pattern
• on the target object with the multi charged particle beams, based on a gray-scale value of the each pixel in the each group for which the dose errors each caused by the gradation by gray scale levels have been corrected.