Patent ID: 6492007
Filing Date: 2002-12-10
Classification: B32B,H05K,Y10S,Y10T

Abstract:
A multi-layer printed circuit bare board comprising:at least two insulative layers each having two generally flat, primary surfaces; circuit layers including electrically conductive material forming electric circuitry and carried on at least one of the primary surfaces of said insulative layers; and bonding layers of insulative material intervening between adjacent ones of said insulative layers and bonding said adjacent insulative layers with each other to accumulate said circuit layers with one above the other; at least one of said insulative layers having a first through hole open to the primary surfaces thereof and filled with electrically conductive material interconnecting the circuit layers carried therein with each other; said first through hole having a substantially circular cross section perpendicular to a longitudinal axis thereof, and having a diameter of 40 micro-meter or less.