Patent ID: 7863160
Filing Date: 2011-01-04
Classification: B23K,H01L

Abstract:
1. A method of processing a wafer having a plurality of devices which are composed of a laminate consisting of an insulating film and a functional film on the front surface of a substrate, along streets for sectioning the plurality of devices by using a laser beam processing machine which comprises a chuck table for holding a workpiece, a first laser beam application means for applying a laser beam to the workpiece held on the chuck table, a second laser beam application means for applying a laser beam to the workpiece held on the chuck table, a processing-feed means for moving the chuck table, the first laser beam application means and the second laser beam application means relative to one another in a processing-feed direction, and an indexing-feed means for moving the chuck table, the first laser beam application means and the second laser beam application means relative to one another in an indexing-feed direction perpendicular to the processing-feed direction, wherein the method comprises a first trip blocking groove forming step for bringing one end of a street of the wafer held on the chuck table to an application position of a laser beam to be applied from the first laser beam application means and activating the first laser beam application means to apply a laser beam having an output capable of dividing the laminate so as to form a blocking groove in the laminate along the street of the wafer while moving the chuck table, the first laser beam application means and the second laser beam application means relative to one another in a first direction in the processing-feed direction; a second trip blocking groove and dividing groove forming step for bringing the other end side of a street next to the street which has undergone the above first trip blocking groove forming step to an application position of a laser beam to be applied from the first laser beam application means and also, bringing the other end side of the blocking groove formed along the street by the first trip blocking groove forming step to an application position of a laser beam to be applied from the second laser beam application means, and activating the first laser beam application means to apply a laser beam having an output capable of dividing the laminate so as to form a blocking groove in the laminate along the street of the wafer and also, activating the second laser beam application means to apply a laser beam having an output capable of forming a dividing groove in the substrate so as to form a dividing groove in the substrate along the blocking groove while moving the chuck table, the first laser beam application means and the second laser beam application means relative to one another in a second direction in the processing-feed direction; and a first trip blocking groove and dividing groove forming step for bringing one end side of a street next to the street where the blocking groove has been formed by the second trip blocking groove and dividing groove forming step to an application position of a laser beam to be applied from the first laser beam application means and also bringing one end side of the blocking groove formed by the second trip blocking groove and dividing groove forming step to an application position of a laser beam to be applied from the second laser beam application means, and activating the first laser beam application means to apply a laser beam having an output capable of dividing the laminate so as to form a blocking groove in the laminate along the street of the wafer and also, activating the second laser beam application means to apply a laser beam having an output capable of forming a dividing groove in the substrate so as to-form a dividing groove in the substrate along the blocking groove while moving the chuck table, the first laser beam application means and the second laser beam application means relative to one another in the first direction in the processing-feed direction, the second trip blocking groove and dividing groove forming step and the first trip blocking groove and dividing groove forming step being repeated.