Patent ID: 8258428
Filing Date: 2012-09-04
Classification: B23K,H01L

Abstract:
1. A laser beam processing machine for forming via holes in a silicon workpiece having bonding pads on a front surface thereof, said processing machine comprising: a chuck table for holding the workpiece, a laser beam application means for applying a laser beam to the workpiece held on the chuck table, the laser beam application means including a pulse laser beam oscillation means for oscillating a pulse laser beam, a beam splitter for dividing the pulse laser beam into a first pulse laser beam and a second pulse laser beam, a first application means for applying the first pulse laser beam, and a second application means for applying the second pulse laser beam, the second application means having a first acousto-optic deflection means, and a second acousto-optic deflection means, a processing-feed means for moving the chuck table and the laser beam application means relative to each other in a processing-feed direction, an indexing-feed means for moving the chuck table and the laser beam application means in an indexing-feed direction perpendicular to the processing-feed direction, and a control means for controlling operation of the laser beam application means, the processing feed means, and the indexing-feed means, wherein the control means causes the first application means to apply the first pulse laser beam at an energy density per pulse of 20 to 60 J/cm