LASER TRIMMING METHOD OF CIRCUIT ELEMENT FORMED OF COPPER FOIL OF PRINTED WIRING BOARD

摘要

PURPOSE:To provide an excellent laser trimming method wherein a copper foil bridge to be formed in the working trench part of a copper foil is excluded, and stable working is realized, when a circuit element formed of the copper foil of a printed wiring board which is used in a high frequency circuit of various kinds of electronic apparatuses is subjected to trimming by using a laser oscillating equipment. CONSTITUTION:The spot diameter (b) of a laser beam 8 on a working surface which beam is irradiated from a laser oscillating equipment is made intendedly larger than or equal to the thickness (a) of a copper foil 2 of a printed wiring board 1. Thereby a working trench 5 of the copper foil 2 is made wide, so that the bridge to be formed by recombination of the copper foil fused in the trench can be excluded.