| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent a mask from rising or getting out of position in laser processing by a method wherein moisture or electric charge is supplied onto the surface of the insulating resin layer of a printed wiring board so as to bring a mask into close contact with the insulating resin layer, a laser beam is made to irradiate the insulating resin layer in spots only through through-holes provided to the mask to bore holes in the insulating resin layer. SOLUTION: Moisture is supplied onto the surface of the insulating resin layer 3 of a printed wiring board, and then a mask 4 with through-holes 4a is brought into close contact with the insulating resin layer 3. Or, the insulating resin layer 3 of the printed wiring board is charged with static electricity, and the mask 4 is brought into close contact with the insulating resin layer 3 taking advantage of an electrostatic force. Then, a laser beam is made to irradiate the insulating resin layer 3 through the through-holes 4a to make blind holes 5 in the insulating resin layer 3. Then, the printed wiring board subjected to laser processing is subjected to copper plating for the formation of a copper plating layer 6. Required blind vias 7 are formed, and thus a multilayer printed wiring board 8 with the blind vias 7 is obtained. By this setup, a mask can be prevented from rising up or getting out of position in laser processing, and the time required for laser processing can be shortened.</p> |
