| 摘要 |
PURPOSE:To dispense with the solder filling of the inside of a viahole so as to improve the electrical connection in reliability by a method wherein an insulating substrate containing catalyst is utilized, where a thermoplastic film is adhered, a hole for a viahole is bored, and then the substrate is dipped into electroless plating solution so as to precipitate copper and fill the inside of the viahole with copper. CONSTITUTION:An adhesive 2 containing catalyst is applied onto both front and rear faces of an insulating substrate 1 and a thermoplastic film 3 with adhesive is adhered to the adhesive layer 2. A hole 6 for a viahole is provided to a substrate 5, which is dipped into electroless plating solution so as to precipitate copper and fill the hole with copper 8. And then, the thermoplastic film 3 is separated off, a hole 10 for a throughhole is bored, and a plating layer 12 is formed. In succession, the substrate is dipped into electroless plating solution, so that a pad 15 of a viahole is formed on both faces of a substrate 20 and a through-hole 18 is formed concurrently. By these processes, the electrical connection is improved in reliability and solder filling of the inside of a viahole can be dispensed with. |
