| 摘要 |
<p>PURPOSE:To make it possible to form a fine wiring layer by providing complex having more than two sets of subassemblies having a construction of formed wiring layers in such a manner that the area ratio will correspond through an insulation layer on both the surfaces of a core material made of a low thermal expansion metal and by reducing dimensional changes of substrate. CONSTITUTION:For the wiring sheet, copper wires 3 are formed on both the surfaces of a polyimide film 2 for which the thermal expansion coefficient was matched to copper. This wiring sheet is laminated on a mullite substrate by an adhesive film 4 and a multilayer laminated board 6 made of wiring sheets is produced. In this case, a core member with the thermal expansion coefficient of 1X10<-5>/ deg.C to 1X10<-7>/ deg.C is provided, for example, an invar foil is inserted to copper-lined polyimide sheets for realizing low heat expansion. By doing this, mismatch of thermal expansion coefficient between copper-lined polyimide sheet and mullite substrate can be reduced.</p> |
