Laser processing apparatus

A laser processing apparatus comprising:

• a chuck table for holding a workpiece;
• a laser beam applying unit for laser-processing said workpiece held on said chuck table;
• and
• a moving mechanism for relatively moving said chuck table and said laser beam applying unit;
• said laser beam applying unit including
• a pulsed laser oscillator for oscillating a pulsed laser beam,
• focusing means for focusing said pulsed laser beam oscillated from said pulsed laser oscillator and applying said pulsed laser beam focused to said workpiece held on said chuck table, and
• a beam swinging unit provided between said pulsed laser oscillator and said focusing means for swinging an optical path of said pulsed laser beam oscillated from said pulsed laser oscillator and then introducing said pulsed laser beam to said focusing means;
• said beam swinging unit including
• a polygon scanner provided on the upstream side of said focusing means for scanning said pulsed laser beam oscillated from said pulsed laser oscillator and introducing said pulsed laser beam scanned to said focusing means, and
• an acoustooptic deflecting unit provided on the upstream side of said polygon scanner and on the downstream side of said pulsed laser oscillator for deflecting the optical path of said pulsed laser beam oscillated from said pulsed laser oscillator and introducing said pulsed laser beam deflected to said polygon scanner,
• whereby the optical path of said pulsed laser beam is swung by the combination of the deflection of the optical path by said acoustooptic deflecting unit and the deflection of the optical path by said polygon scanner and said pulsed laser beam thus swinging is applied to said workpiece held on said chuck table.