The effect of 2-mercaptobenzothiazole on laser-assisted electroless copper plating

Abstract

The effect of 2-mercaptobenzothiazole (2-MBT) on laser-assisted electroless copper plating, using formaldehyde as a reducing agent as well as ethylenediaminetetraacetic acid (EDTA) and ethylenediaminetetrapropionic acid (EDTP) as complexing agents, has been investigated. The surface morphology, roughness, and crystallinity of copper coating depend on the 2-MBT concentration. The plating rate enhances significantly with the increase of 2-MBT contents. Accelerating mechanism of electroless copper plating has been studied by means of Tafel plots and linear sweep voltammetry. It is found that the appropriate amount of 2-MBT can improve the quality of copper coatings and accelerate the electroless copper plating process due to the promotion of the controlling step, as 2-MBT additions can form new electrostatic forces resulting in the decrease of absorption of [CH₂(OH)O⁻]_ad or H_ad and then make the controlling step occur more easily.