Patent ID: 8756805
Filing Date: 2014-06-24
Classification: H01B,H05K,Y10T

Abstract:
1. A method of manufacturing a multilayer printed wiring board, comprising: forming a hole through a pre-preg by drilling by laser beam machining, filling the hole with conductive paste containing a resin component and metal powder comprising a mixture of at least two different powders, each of the different powders being of a different metal, and arranging copper layers or copper layer portions of patterned boards on and under the filled conductive paste and pressing the same, wherein in the conductive paste at least surface layers of the different metal powders are melted whereby the metals of the different metal powders adjacent to each other are alloyed, the pre-preg has a ratio of A divided by B of at least 10 before being subjected to preheating, where A is a storage modulus at an inflection point where the storage modulus changes from increasing to decreasing and B is a storage modulus at an inflection point where the storage modulus changes from decreasing to increasing in a temperature profile rising from 60° C. to 200° C., and preheating the pre-preg before the drilling to reduce the ratio of A divided by B to below 10.