| 摘要 |
PROBLEM TO BE SOLVED: To improve a solder connection reliability of a BGA package product for semiconductor which can be mass-produced with a single layer wiring and a multi-surface connection at low cost. SOLUTION: A metal foil layer which can be mechanically exfoliated is formed on one surface of an insulating supporting body layer 10 and used as a mask for processing via holes for an alkali etching processing method or a wet blast processing method. As a result, the via hole pattern is opened in a forward tapered shape. The difficulty in causing a crack in a solder in the via hole and the rough surface in the via hole of the insulating supporting body layer and the rough exposed surface of the via hole of the wiring copper foil 20 improve the solder connection reliability. COPYRIGHT: (C)2007,JPO&INPIT
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