| CPC H01J 37/3171 (2013.01) [H01J 37/304 (2013.01); H01J 2237/24535 (2013.01)] | 24 Claims |
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1. An ion implantation method comprising:
generating a first scan beam by performing a reciprocating scan using a spot-like ion beam in a predetermined direction, based on a first scan signal;
measuring a beam current of the first scan beam by using a beam measurement device at a plurality of measurement positions different in the predetermined direction;
calculating a beam current matrix in which beam current values with respect to a plurality of positions different in the predetermined direction and a plurality of scan command values are set as components, based on a time waveform of the beam current measured by the beam measurement device and a time waveform of the scan command values determined in the first scan signal;
calculating a first beam current density distribution of the first scan beam in the predetermined direction by performing time integration on the measured beam current;
correcting a value of each component of the beam current matrix, based on the first beam current density distribution; and
generating a second scan signal for realizing a target beam current density distribution in the predetermined direction, based on the corrected beam current matrix,
wherein the second scan signal is generated by performing an optimization calculation so that an evaluation function in which a first evaluation value and a second evaluation value are combined is minimized,
wherein the first evaluation value evaluates a difference between a beam current density distribution calculated based on the corrected beam current matrix and a candidate second scan signal, and the target beam current density distribution, and
wherein the second evaluation value evaluates variations in time change rates of scan command values in the candidate second scan signal.
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