| 摘要 |
PURPOSE:To stabilize quality with no current concentration and to decrease width of copper circuit patterns and to miniaturize the whole of circuits, by standardizing thickness of the whole of copper circuit patterns to be 35 mum or more. CONSTITUTION:Thick copper foil parts 1 as lower layers composed of heterogeneous metal composite foils are laminated on a base metal 6 through an insulating layer 5, and also aluminium bonding posts 3 as upper layers are laminated thereon. Power transistors 7 and diodes 8 are connected with the aluminium bonding posts 3 by the use of aluminium wires 9 so as to form circuits. Thickness of each copper foil thick part of the heterogeneous metal composite foils used in this invention is required to be 35mum or more, and large current conduction capacity can not be obtained when this thickness is 35mum or less. Though an upper limit is not restricted, this limit is 300mum or so in consideration of cost. Then, for example, silicon resin can be singly used or filler-containing silicon resin of good heat conductivity can be used as gelled silicon group resin which seals the circuits.
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