MULTILAYER PRINTED WIRING BOARD AND METHOD FOR MANUFACTURING SAME

摘要

A multilayer printed wiring board is characterized in that the interlayer connection material in the via holes has a lower coefficient of thermal expansion in the thickness direction than the electrically insulating substrate made of insulating material; the interlayer connection is formed at a temperature higher than the operating temperature; and the interlayer connection material is larger in thickness than the interlayer connection material of the same wiring layer at normal temperature. This causes a difference in the coefficient of thermal expansion between the different materials in the thickness direction of the printed wiring board in the environment in which it is used. As a result, the internal stress always functions to contract the interlayer connecting portion. Contracting the interlayer connecting portion in this manner achieves a multilayer printed wiring board having high connection reliability.