| 摘要 |
PURPOSE:To provide the method for formation of through-holes of high reliability which solves the problem of the degradation in the reliability of a through- hole wiring board by the generation of burrs and the formation of carbides in the method for formation of the through-holes of the circuit board to be used for electronic equipment, etc. CONSTITUTION:The desired points of an insulating layer consisting of the composite material or green sheet of arom. polyamide fibers and thermosetting resin are partially heated and removed by a CO2 laser of square pulse waves, by which the through-holes are formed. As a result, the formation of the burrs and carbides is obviated and the generation of the disconnection, etc., of the conductive layers for the through-holes is prevented and, therefore, the circuit board having the high reliability is obtd. |
