Through hole electroplating process for printed circuit board

Abstract

The invention discloses a through hole electroplating process for a printed circuit board. The through hole electroplating process comprises the steps of deoiling: stains and oxide layers on a coppersurface of the printed circuit board before electroplating are removed by using an acidic degreasing agent, wherein the deoiling is operated under the temperature of 43-54 DEG C for 3-5 minutes; rinsing: the printed circuit board subjected to the treatment of the degreasing agent is rinsed by adopting flowing deionized water to match with mechanical swinging, wherein the rinsing is operated underthe temperature of 20-28 DEG C for 2-4 minutes; pre-soaking: pre-cleaning is carried out on the printed circuit board before electroplating by using a dilute sulfuric acid solution in cooperation withmechanical swinging and a filtering circulating system, wherein the concentration of the dilute sulfuric acid solution is 10%, and the pre-soaking is operated under the temperature of 20-28 DEG C for1-3 minutes; and electroplating: the printed circuit board is electroplated by utilizing electroplating chemicals, the filtering circulating system, mechanical swinging and jet flow, wherein the electroplating is operated under the temperature of 23-26 DEG C, and the electroplating chemicals comprise an electroplating base solution and an electroplating additive. The through hole electroplating process for the printed circuit board is characterized in that the electroplating time can be shortened to the maximum extent, and the production efficiency can be improved.

Description

technical field [0001] The invention relates to the field of electroplating, in particular to a hole electroplating process of a printed circuit board. Background technique [0002] During the DC electroplating process of the through hole, the current density at the hole is often higher than the current density at the middle of the hole, so that the current distribution in the hole gradually decreases from the edge of the hole to the center of the hole, resulting in a large amount of copper deposited on the surface and the edge of the hole. Make sure the copper in the center of the hole is as thick as it should be. [0003] For high-aspect-ratio circuit boards, in order to reduce this phenomenon, it is usually used to reduce the current density, increase the conductivity of the solution, and use a high-acid and low-copper electroplating bath configuration with appropriate air stirring to increase the copper thickness in the through hole. The effect of electroplating additiv...

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Problems solved by technology

[0004] However, this electroplating method takes a long time, which leads to low production efficiency and affects the electroplating capacity. More importantly, it cannot ensure the integrity of the electroplated copper layer in the deep hole. It is possible that the current has not reached the center of the hole, and part of the conductive layer has been destroyed. to dissolve

[0005] As the aspect ratio of printed circuit boards is getting higher and higher, the problem of insufficient copper plating thickness in through holes cannot be completely overcome by using low current density; and for printed circuit boards with high thickness, only air stirring still exists due to the exchange of plating solution in the hole Insufficient copper thickness in the hole due to poor penetration; at the same time, the use of air agitation will cause tailing of the hole, resulting in differences in the color of the copper-plated surface of the hole, and uneven copper thickness on the upper and lower sides

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