In FPC bored after after processing the first hole wall adsorption layer of the palladium, palladium as a catalyst in sink copper cylinder REDOX reaction layer both for the FPC board of any part of the deposit on the copper to achieve the purpose of hole conduction, control the intensity of the REDOX reaction of different thickness of copper layer, in turn, are thin and thick copper in the copper, copper. Company main products are now sink copper level, due to the level of heavy copper superior ability of square holes (especially blind holes and high aspect ratio of plate) and horizontal operation mode is particularly suitable for high-end products and high reliability products processing.