| 摘要 |
PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus which can form simultaneously two layers of a modified layer in the interior of a workpiece, and is easy to control.SOLUTION: A laser beam machining apparatus includes a chuck table and a laser beam irradiating means 5, wherein the laser beam irradiating means is equipped with a laser beam oscillating means 51, a branching means 52 which branches the laser beam into a first and a second optical path, a first optical path means and a second optical path means 53, 54 arrangedly provided in the first and the second optical path respectively, a merging means 55 which merges the first laser beam and the second laser beam passing through, and leads it to a third optical path, an aberration correction lens 56 arrangedly provided in the third optical path, a condenser lens 57 which generates a first and a second condensing spot by condensing the first and the second laser beams, a first moving means 58 which makes the first optical path means come close to or depart from the aberration correction lens through the merging means, and a second moving means 59 which makes the second optical path means come close to or depart from the aberration correction lens through the merging means. |
