Effect of Corrosion Inhibitors on Copper Etching to Form Thick Copper Line of PCB in Acidic Etching Solution

Abstract

The chemical compounds of 2-mercaptobenzothiazole (2-MBT), benzotriazole (BTA) and phenoxyethanol (MSDS) as corrosion inhibitors were used to inhibit the copper etching to form the thick copper line of PCB in the acidic etching solution. The inhibition status was characterized with contact angle measurement, electrochemical test and etch factor calculation, while the corrosion morphology of copper surface was studied by scanning electron microscope. The adsorption mechanism of corrosion inhibitors on copper surface is analyzed by molecular dynamics and quantum chemistry calculations. The results indicated that the synergistic function of the two inhibitors could effectively promote their adsorption on the copper surface in parallel, while their adsorption energy could be higher than that of the single inhibitor. The etch factor of the thick copper line with about 33 μm in thickness increased to 6.59 from the etching solution with 2-MBT and MSDS for good agreement of PCB manufacture.

Keywords

corrosion inhibitor / synergistic function / thick copper line / acidic etching solution

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