Charged particle beam writing method and charged particle beam writing apparatus

A charged particle beam writing apparatus in which a deflector is caused to deflect a charged particle beam and a pattern is written by irradiating, with the charged particle beam, a substrate on which a resist film is formed, the charged particle beam writing apparatus comprising:

• an emitter emitting the charged particle beam;
• a pattern density calculation circuit virtually dividing a writing region of the substrate in a mesh having grid dimensions and calculating a pattern density representing an arrangement ratio of the pattern for each mesh region;
• a dose calculation circuit calculating a dose representing a dose for each mesh region using the pattern density;
• a storage storing a function for charge amount calculation, the function using, as variables, a film thickness of the resist film and the dose;
• a charge amount calculation circuit retrieving the function from the storage, using the function, and calculating a charge amount based on the film thickness of the resist film formed on the substrate and the dose calculated by the dose calculation circuit as variable, and based upon a secondary electron yield, a permittivity, a resistivity during beam irradiation, a work function, and a positive-hole residual rate of resist, as parameters;
• a position shift amount calculation circuit calculating a position shift amount of a writing position from the charge amount;
• a corrector correcting, using the position shift amount, an irradiation position of the charged particle beam;
• and
• a writer irradiating the corrected irradiation position with the charged particle beam,
• wherein the function for charge amount calculation is independent of a dose sensitivity of the resist film.