Patent ID: 6972392

Claim:
A laser beam machining method for a wiring board, using a laser beam for machining such as drilling for a through-hole and a blind via hole, grooving, and cutting for an outside shape of the wiring board with a metallic layer formed on a base material surface, and the method comprising the steps of: forming the metallic layer having a desired shape by partially removing the metallic layer by pulse irradiation with a laser beam having sufficient intensity to melt and remove the metallic layer; and additionally irradiating a machined portion of the wiring board through the metallic layer removed portion with the laser beam having insufficient intensity to melt the metallic layer and a beam irradiation time ranging from 10 to 200 μs, and including a plurality of pulses forming a train at intervals of a beam irradiation pausing time of 15 ms or more.