| 摘要 |
<p>PROBLEM TO BE SOLVED: To form microscopic via holes with a CO2 laser having good dimensional accuracy. SOLUTION: In a via hole formation process, first the surface of an insulating resin layer 27 is roughened, and after an electroless Cu plated film 31 is formed on the layer 27, a photosensitive resin layer 33 is formed on the surface of the film 31. Then, exposure and developing are performed on the layer 33, so that only the parts, which are formed with via holes of this layer 33 are left to form plated resists 33a for via hole formation. After this, after an electrolytic Cu plated film 32 having holes 34 for via hole formation is formed on the surface of the film 31 using the plated resists 33a, the plated resists 33a are removed. Then, after the holes 34 for via hole formation are formed in the film 31 through etching using the film 32 as an etching resist, the via holes are formed in the insulating resin layer 27 with CO2 laser using the film 32 as a mask.</p> |
