Method of manufacturing multilayer printed wiring board

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.