| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To easily punch holes whose diameter is small at the time of forming through-holes in a multi-layer printed wiring board integrated into various electronic equipment. <P>SOLUTION: Insulating layers 2, 3, and 4 and conductor layers 7, 8, 9, and 10 are alternately laminated on a multi-layer printed wiring board 1; and a hole forming part 15 of a multi-layer printed wiring board 1 is irradiated with a quadruple wave ultraviolet laser whose mean energy density ranges from 5 to 20J/cm<SP>2</SP>at a 1kHz or more repeat frequency. Thus, the configuring elements of the multi-layer printed wiring board 1 are ablated in a molecular level by the four-time wave ultraviolet laser, and a through-hole 5 or a stop hole 6 whose diameters D1 and D2 are small, that is, about 10 to 20μm are formed. In this case, the working of glass fibers and conductor layers 7, 8, 9, and 10 in the insulating layer 2 is not accompanied with any difficulty. Also, the debris of the resin of the insulating layers 2, 3, and 4 can be prevented from staying at the bottom of the stop hole 6, and from disturbing the conduction of the conductive hole. Also, at the time of forming a plurality of conductive holes, productivity can be increased by improving the punching speed, if a multistage cyclic perforation is employed. <P>COPYRIGHT: (C)2004,JPO</p> |
