Charged particle beam writing method, charged particle beam writing apparatus and computer-readable recording medium

A charged particle beam writing apparatus for writing a pattern on a substrate using a charged particle beam, the charged particle beam writing apparatus comprising:

• a rasterization unit that virtually divides a writing region of the substrate into a plurality of first mesh regions having a first mesh size, and calculates a pattern area density of each of the first mesh regions to create a first area density map;
• a sampling unit that samples the first area density map with second mesh regions having a second mesh size smaller than the first mesh size, and creates a second area density map defining a pattern area density for each of the second mesh regions;
• a calculation unit that calculates an irradiation amount for each of the second mesh regions using the second area density map;
• and
• a writing unit that irradiates the substrate with the charged particle beam in the calculated irradiation amount.

A computer readable recording medium storing a program causing a computer to execute a process comprising:

• a step of virtually dividing a writing region of a substrate into a plurality of first mesh regions having a first mesh size, the substrate being written with a pattern using a charged particle beam;
• a step of calculating a pattern area density of each of the first mesh regions to create a first area density map;
• a step of sampling the first area density map with second mesh regions having a second mesh size smaller than the first mesh size, and creating a second area density map defining a pattern area density for each of the second mesh regions;
• a step of calculating an irradiation amount for each of the second mesh regions using the second area density map;
• and
• a step of controlling a writing unit to irradiate the substrate with the charged particle beam in the calculated irradiation amount.