LASER BEAM MACHINING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus which is provided with a height position detection function quickly and accurately measuring an upper surface height of a workpiece.SOLUTION: There is provided the laser beam machining apparatus which includes: laser beam irradiation means 9 provided with an objective condenser lens 65 for irradiating a workpiece W held by a chuck table 36 with a laser beam; interference-type height position detection means 6 which detects an upper surface height of the workpiece by interference between a reflected light and a reference light; condensing point positioning means 650 which moves the objective condenser lens vertically; and control means 80 which controls the condensing point positioning means based on the upper surface height of the workpiece detected by the interference-type height position detection means. The laser beam machining apparatus further includes confocal optical height position detection means 11 which detects the upper surface height of the workpiece. The control means sets the difference between the upper surface height position detected by the confocal optical height position detection means and the upper surface height position detected by the interference-type height position detection means as a correction value, and controls the condensing point positioning means based on the corrected height position obtained by correcting the upper surface height position of the workpiece detected by the interference-type height position detection means using the set correction value.