| abstract |
In a method of manufacturing a multilayer board, including: a drilling step for forming a via hole through a pre-preg by laser beam machining, a step of filling the via hole with conductive paste containing a resin component and metal powder, and a step of arranging copper layers or copper layer portions of patterned boards on and under the filled conductive paste and pressing the same, a multilayer printed wiring board superior in conductivity and long-term stability is obtained by using alloying paste as the conductive paste in which at least part of the metal powder is melted and the metal powders adjacent to each other are alloyed, using a pre-preg having a ratio A/B of at least 10 before 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 step to reduce the ratio A/B to below 10. |