Cyanide-free copper electroplating method for reducing porosity of copper plating layer

Abstract

The present invention relates to a cyanide-free copper electroplating method for reducing porosity of a copper plating layer. According to the cyanide-free copper electroplating method, a substrate is alternately subjected to a direct current electroplating unit and a pulse electroplating unit, the pH value of the electroplating solution is controlled to 12-13, the temperature is 50-70 DEG C, the cathode current density for copper electroplating in each direct current electroplating unit is 0.5-3.0 A / dm<2>, the electroplating time is 2-3 min, the pulse average current density for copper electroplating in each alternating current electroplating unit is 0.5-3.0 A / dm<2>, the duty ratio is 15%, and the electroplating time is 2-3 min. The plating layer obtained through the method has minimal porosity when the plating layer thickness is 10-20 mum.

Description

technical field

[0001] The invention relates to a method for electroplating copper, in particular to a method for reducing the porosity of a copper plating layer without cyanide electroplating. Background technique

[0002] The cyanide electroplating copper layer has fine crystallization, good bonding force, good leveling, leveling and stability of the plating solution, and can be directly electroplated on steel, zinc and zinc alloy substrate parts. However, the cyanide electroplating copper solution contains cyanide ions, which is highly toxic, difficult to handle waste water and liquid waste, seriously pollutes the environment, and endangers human health. Therefore, people have been looking for a cyanide-free copper plating process that can replace cyanide electroplating copper. The existing cyanide-free copper plating process mainly has the following types:

[0003] (1) Sulfate copper plating

[0004] Sulfate acidic copper plating solution is mainly composed of copper ...