Method for processing ceramic green sheet and laser beam machine used therefor

A laser beam machine for forming a plurality of penetration holes in a ceramic green sheet, comprising:

• a support adapted to support a ceramic green sheet;
• a laser beam source adapted to radiate a laser beam;
• a mask arranged to shape the laser beam from the laser beam source into a predetermined shape;
• a diffraction grating arranged to divide the laser beam passed through the mask into a plurality of laser beams comprising a zero order laser beam, a first order laser beam and a second order laser beam such that an energy of an individual diffracted zero order laser beam becomes equivalent to, or less than, a threshold value which is necessary to form a penetration hole in the ceramic green sheet;
• a galvanomirror arranged to reflect laser beams passed through the diffraction grating at a predetermined reflection angle;
• a galvanomirror drive arranged to change the reflection angle of the galvanomirror;
• and
• a converging lens arranged to converge individual laser beams reflected by the galvanomirror and to radiate the converged laser beams to a plurality of points of a ceramic green sheet when arranged on the support.