Patent ID: 7821703

Claim:
A method of laser drawing for laser annealing of semiconductor devices, comprising: causing laser light from a light source to be incident on an acousto-optical diffraction element; and deflecting the light incident on the acousto-optical diffraction element by changing a frequency of a high frequency signal inputted to the acousto-optical diffraction element, thereby changing a diffraction angle of the diffracted light, and condensing the diffracted light emerging from the acousto-optical diffraction element through an intermediate optical lens system and a condensing lens on an object to be processed as an optical spot of the diffracted light, thereby scanning the object with the optical spot of the diffracted light, wherein diffracted light intensity control data for controlling an amplitude of the high frequency signal inputted to the acousto-optical diffraction element so as to keep a light intensity of the diffracted light emerging from the acousto-optical diffraction element constant independent of the diffraction angle based on determined device operation information, and wherein the amplitude of the high frequency signal inputted to the acousto-optical diffraction element is controlled based on the diffracted light intensity control data, thereby the light intensity of the diffracted light emerging from the acousto-optical diffraction element is kept constant independent of the diffraction angle of the diffracted light, wherein the diffracted light intensity control data includes frequency instructing values specifying frequencies of the high frequency signal inputted to the acousto-optical diffraction element and amplitude control values for controlling the amplitude of the high frequency signal so as to keep the light intensity of the diffracted light emerging from the acousto-optical diffraction element constant independent of the diffraction angle of the diffracted light, the amplitude control values being related to inverse diffraction efficiency values when the diffraction angle of the diffracted light emerging from the acousto-optical diffraction element is changed by changing the frequency of the high frequency signal input to the acousto-optical diffraction element.