Laser processing method and laser processing apparatus

Abstract

A laser beam machining method and a laser beam machining device capable of cutting a work along a predetermined cutting line on the surface of the work, wherein a pulse laser beam is irradiated on the predetermined cutting line on the surface of the work causing a multiple photon absorption with a condensed point arranged inside the work, and a modified area is formed inside the work along the predetermined determined cutting line by moving the condensed point along the predetermined cutting line, whereby the work can be cut with a small force by cracking the work along the predetermined cutting line starting from the modified area.

1 - 44 . (canceled) 
     
     
         45 . A laser processing machining apparatus comprising:
 a light source for emitting pulse laser light having a pulse width of 1 μs or less;   ellipticity adjusting means for making the pulse laser light emitted from the laser light source attain elliptical polarization with an ellipticity of other than 1;   major axis adjusting means for adjusting a major axis of the pulse laser light so that the major axis of an ellipse indicative of the elliptical polarization of the pulse laser light extends along a line along which the object is intended to be cut in an object to be processed;   light-converging means for converging the pulse laser light adjusted by the major axis adjusting means such that the pulse laser light attains a peak power density of at least 1×10 8  (W/cm 2 ) at a light-converging point;   means for locating the light-converging point of the pulse laser light converged by the light-converging point within the object to be processed; and   moving means for relatively moving the light-converging point of pulse laser light along the line along which the object is intended to be cut.   
     
     
         46 . A laser processing apparatus according to  claim 45  further comprising 90° rotation adjusting means adapted to rotate the polarization of the pulse laser light adjusted by the ellipticity adjusting means by about 90°. 
     
     
         47 . A laser processing apparatus according to  claim 45 , further comprising rotating means for rotating a stage adapted for mounting the object to be processed by about 90° about a thickness direction of the object. 
     
     
         48 . A laser processing apparatus comprising:
 a laser light source for emitting pulse laser light having a pulse width of 1 μs or less and linear polarization;   linear polarization adjusting means for making the direction of linear polarization of the pulse laser light emitted from the laser light source align with a line along which the object is intended to be cut in an object to be processed;   light-converging means for converging the pulse laser light adjusted by the linear polarization adjusting means such that the pulse laser light attains a peak power density of at least 1×10 8  (W/cm 2 ) at a light-converging point;   means for locating the light-converging point of the pulse laser light converged by the light-converging point within the object to be processed; and   moving means for relatively moving the light-converging point of pulse laser light along the line along which the object is intended to be cut.   
     
     
         49 . A laser processing apparatus according to  claim 48 , further comprising rotating means for rotating a stage adapted for mounting the object to be processed by about 90° about a thickness direction of the object.