| 摘要 |
PURPOSE:To hold preferable bondability with an aluminum base material and an insulating resin layer even in case of soldering and to form an aluminum circuit substrate having excellent heat sink by subjecting the aluminum base material to an anodic oxidation by oxalic acid bath, and then sealing the holes. CONSTITUTION:An insulating resin layer made of glass epoxy is bonded on an aluminum circuit substrate material coated with unsealed porous oxalic acid film on the surface of an aluminum base material. A copper foil is bonded as required on the resin layer, and circuit elements such as a resistor, a conductive member and a transistor are bonded directly on the resin layer. The excellent thermal resistant bondability of the resin layer and the oxalic acid film is considered to be caused by the preferable crack resistance of the oxalic acid film as compared with other surface treated film. The excellent crack resistance enables to reduce the thickness of the insulating resin layer and to improve the heat sink of the circuit substrate.
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