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

A multi charged particle beam writing apparatus comprising:

• an aperture plate including a plurality of apertures through which a charged particle beam passes to form multiple beams;
• a blanking aperture array including a plurality of blankers each switching a corresponding one of the multiple beams between a beam ON state and a beam OFF state;
• a movable stage on which a writing target substrate is placed;
• a stage position detector detecting the position of the stage;
• an inspection aperture plate provided in the stage, the inspection aperture plate permitting one of the multiple beams to pass through the inspection aperture plate;
• a deflector deflecting the multiple beams;
• a current detector detecting a beam current of each of the multiple beams scanned over the inspection aperture plate in X and Y directions and passed through the inspection aperture plate;
• and
• electric circuitry generating a beam image based on the detected beam currents and calculating positions of the beams based on the beam image and the position of the stage,
• wherein the inspection aperture plate includes a through hole through which the one of the multiple beams passes, and
• a diameter ϕ1 of the through hole satisfies a following condition:
• S<ϕ1<P−S,
• wherein S is a beam size of the one of the multiple beams, and P is a beam pitch of the multiple beams on the writing target substrate.