Multilayer printed wiring board

摘要

There is provided a multilayer printed wiring board in which each of insulating layers is 100 µm or less in thickness. Each of a plurality of viaholes electrically connecting conductor circuits on the insulating layers to each other is formed tapered inwardly from the surface of the insulating layer and the viaholes are disposed opposite to each other to form a multistage stacked via. This structure enables controlling such external stress as drop shock generated when the board is dropped and preventing the insulating substrate from warping, which leads to preventing cracking and disconnection of conductor circuit and minimizes the decrease of reliability and resistance to drop shock of the board.