| 摘要 |
PROBLEM TO BE SOLVED: To directly mount various kinds of electronic parts reliably by laminating metal foil having specified hot elongation at a specified temperature on an insulating substrate made of a backing having a coefficient of thermal expansion not exceeding a specified value and a resin. SOLUTION: A backing with a coefficient of thermal expansion not exceeding 3×10<-6> / deg.C is impregnated with a resin and dried to be used as the insulating substrate of a metal foil laminated substrate. Metal foil with hot elongation of 10-50% at 130-200 deg.C is laminated on the insulating substrate. The metal foil is brought into a low stress state at a temperature close to that at the connection between a surface-mounted part and a multilayer printed wiring board, acting as a buffer layer to alleviate the affection due to the difference in thermal expansion/contraction between the surface-mounted part and the substrate caused by the heat during connection work. When the hot elongation of the metal foil in the temperature range is below 10%, the affection due to the difference in expansion/contraction by the heat during connection work can not be alleviated, and the elongation exceeding 50% causes the deterioration in handling and facilitates wrinkling during lamination. |
