The processed after PCB drilling hole wall first adsorption layer of palladium and palladium as a catalyst in sink copper cylinder REDOX reaction for any part of the PCB is on a layer of sedimentary copper to achieve the purpose of hole conduction, control the intensity of the REDOX reaction of different thickness of copper layer, and then have a thin and thick copper in the copper, copper. Company main product is horizontal sink copper, due to horizontal sink 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 .