Patent ID: 8872139

Claim:
A settling time acquisition method comprising: writing, on a target object, at least one reference pattern formed by at least one shot of a charged particle beam having been shaped by using a first shaping aperture, a second shaping aperture, and a deflector for deflecting the charged particle beam passing between the first shaping aperture and the second shaping aperture; writing, on the target object, an evaluation pattern, which has been formed by a combination of two shots of a first shot and a second shot of a charged particle beam having been shaped to a first pattern and a second pattern of different sizes by using the first shaping aperture, the second shaping aperture, and the deflector, and whose pattern width size after being resolved is a same in design as that of the reference pattern, while changing, with respect to beam shaping of the second shot, a settling time of a DAC (digital/analogue converter) amplifier for controlling the deflector, wherein the writing is performed for each of the settling time; measuring a pattern width size of the reference pattern; measuring the pattern width size of the evaluation pattern for the each of the settling time; calculating, for the each of the settling time, a difference between the pattern width size of the reference pattern and the pattern width size of the evaluation pattern; and acquiring a settling time from the each of the settling time of the DAC amplifier in a case where the difference is less than or equal to a threshold value.