Charged particle beam drawing apparatus and charged particle beam drawing method

A cell projection exposure charged particle beam drawing method comprising the steps of:

• using a charged particle beam source to emit a charged particle beam;
• exposing a first mask to said charged particle beam, said first mask having a main aperture and a supplementary aperture formed therein, said supplementary aperture having a size 1/Nth of the main aperture, wherein N is an integer;
• exposing a second mask to said charged particle beam through the main aperture of the first mask, said second mask having at least one cell projection exposure aperture formed therein;
• using a combination of said main aperture of said first mask and said cell projection exposure aperture of said second mask to pattern the cell array pattern area on said sample wafer;
• and
• using a combination of said supplementary aperture on said first mask and a partial exposure aperture on said second mask to form an excess cell array pattern.