| 摘要 |
PROBLEM TO BE SOLVED: To ensure high connection reliability for both primary mounting and secondary mounting by laminating and integrating a plurality of both side copper clad substrates having different coefficient of thermal expansion containing a metal foil in an insulation layer through adhesive layers in the order of coefficient of thermal expansion. SOLUTION: First through third both side copper clad substrates 13 are laminated collectively in the order of coefficient of thermal expansion using adhesive layers 10 to produce a multilayer circuit board. In order to electrically connect the both side copper clad substrates 1-3 of the multilayer circuit board thus produced, through holes are drilled after collective lamination and subjected to through hole plating. A multilayer circuit board thus produced can be provided with a gradient in the coefficient of thermal expansion in the thickness direction thereof. Consequently, the coefficient of thermal expansion can be set low for the silicon chip mounting face having a low coefficient of thermal expansion and can be set high for the secondary mounting face to a glass epoxy substrate having a high coefficient of thermal expansion. According to the arrangement, highly reliable primary mounting and secondary mounting can be realized. |
