HIGH DENSITY PRINTED WIRING BOARD

摘要

A high density printed wiring board, on which terminal pads are provided and high density semiconductor devices each having input and output terminals are mounted through the terminal pads, is provided with via pads which are internally connected with respective previously designated circuits of the board and are placed adjacent each terminal pad and are electrically connected with the corresponding terminal pad by a wiring pattern provided on the surface of the board. When the destination of the terminal pad is to be modified for connection with another circuit of the board, the wiring pattern is severed and electrical connection between the terminal pad and the other circuit is made using insulated new discrete wiring wired on the surface of the board. Modification pads for relaying the new wiring are provided on the surface of the board in areas adjacent to and surrounding the region where the terminal pads are located or arranged within such region so that each modification pad is disposed adjacent a corresponding terminal pad and via pad.