| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a method for forming a small-diameter through hole and/or a blind via hole having good hole shape, hole quality and hole diameter suitable for a high density printed circuit board by radiating a carbonic acid gas laser, and a method for perforating an aperture with small contamination of an fθlens. SOLUTION: The method for forming a hole at a copper-clad board by a carbonic acid gas laser comprises the steps of disposing the auxiliary material 2 on a surface of a copper foil (b) of a copper-clad board, perforating the hole at an auxiliary material (a) by a first shot by directly radiating the laser of an output selected by 10 to 60 mJ/pulse suitably from above the material (a) (2), forming the through hole and/or the blind via hole by perforating the hole at the copper foil of the surface by a second shot (3). The method further comprises the steps of placing a metal plate adhered with a resin layer at a lower side in the case of perforating the through hole. Thus, a molten copper splash scattered from the lower side is suppressed when the copper foil of the lower surface is formed. Then, the small-diameter through hole and/or the blind via hole having excellent hole shape, hole quality and hole diameter can be perforated. A contamination of the fθlens due to scattering of the copper foil or the like generated when perforated can be suppressed.</p> |
