The method of sinking copper on the pcb board

Abstract

The present invention relates to the field of manufacturing PCB boards, in particular to a method for depositing copper on a PCB board, including an activation process, the activation process includes the first activation and the second activation in different activation cylinders, and the second activation The activation intensity of the secondary activation cylinder is less than that of the first activation cylinder. First of all, the first activation plays the role of the main activation, basically satisfying the effect of activating the hole wall; the second activation plays the role of auxiliary or supplementary activation, because the activation intensity of the second activation cylinder is relatively low, the activation solution can be more It can easily enter the hole and activate the hole wall more effectively and fully. To a certain extent, it can better make up for the defects that may be left by the first activation, so that the probability of thin copper and no copper phenomenon in the hole will appear. Greatly reduced.

Description

technical field [0001] The invention relates to the field of PCB board manufacture, in particular to a method for depositing copper on a PCB board. Background technique [0002] Electroless Plating Copper (Eletcroless Plating Copper) is also commonly known as sinking copper or porosity (PTH) is an autocatalytic redox reaction. First, it is treated with an activator, so that the surface of the insulating substrate is adsorbed with a layer of active particles, usually metal palladium particles, copper ions are first reduced on these active metal palladium particles, and these reduced metal copper crystal nuclei It becomes the catalytic layer of copper ions again, so that the reduction reaction of copper continues on the surface of these new copper crystal nuclei. [0003] Electroless copper plating has been widely used in the PCB board manufacturing industry. The typical application is the hole metallization of the PCB board. Carry out the subsequent electroplating copper pr...

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Problems solved by technology

[0004] Palladium is a very expensive metal, the price is high and has been rising. In the copper sinking process, the cost of palladium accounts for about 80% of the cost of the copper sinking process. In many factories, the main consumption of palladium is not adsorbed on the PCB board. Necessary consumption, but the consumption of the PCB board. Some manufacturers reduce the consumption of palladium by reducing the concentration of activated palladium in the activation cylinder, prolonging the time of changing the cylinder of activated palladium and prolonging the dripping time of the PCB board in the activation cylinder, but these The method poses a challenge to the quality of the PCB board to a certain extent

Reducing the concentration of activated palladium in the activation cylinder will easily lead to insufficient activation strength, which cannot guarantee the activation effect of the entire hole wall, and will easily cause poor backlight. If the cylinder is not changed for a long time, the activation solution in the cylinder will age, and there will be many suspended impurities in the solution. The surface of the hole is rough and there is even no copper in the hole. Excessively prolonging the dripping time in the activation tank may cause the activated palladium to be oxidized, which will have a negative impact on the subsequent copper deposition process, and the probability of no copper or thin copper in the hole will increase.

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