Patent ID: 9734984
Date: 2017-08-15
CPC Classifications: G01R,H01J

Claim:
1. A current quantity measuring method of multi-beams, the method comprising: irradiating with a charged particle beam; converting, in a minute current measurement unit, multi-beams passed through a plurality of aperture holes of an aperture member having the plurality of aperture holes for forming the multi-beams by irradiation with the charged particle beam, into an electric signal, and then amplifying the electric signal; receiving, in a digitizer, the electric signal amplified in the minute current measurement unit and counting the number of electrons in the multi-beams; calculating a current quantity of the multi-beams passed through the plurality of aperture holes by using a product of the calculated number of electrons in the multi-beams and elementary charge; and correcting, in a correction unit, irradiation time of the charged particle beam of each of the plurality of aperture holes on the basis of the calculated current quantity.