Copper electroless plating in weakly alkaline electrolytes using DMAB as a reducing agent for metallization on polymer films

Copper electroless plating at low pH (7–9) using dimethylamine borane complex as a reducing agent is studied electrochemically by linear sweep voltammetry, cyclic voltammetry and chronopotentiometry in full electrolytes. We find that the mixed potential theory is not applicable to the described system. We show that both the working potential and the rate-controlling mechanism are dependent on the pH of the solution. The effects of altering the mechanism on the resulting film conductivity, morphology and adhesion are studied on copper films deposited onto a polyimide (PI) substrate.

► Low pH (7-9) Cu electroless process using DMAB as a reducing agent is studied. ► Mixed potential theory is inapplicable in the system. ► Rate controlling mechanism switch is found with changing pH. ► Polymer substrate is metalized at various pH. ► Low pH (7–8) shows the best resulting film quality (conductivity and adhesion).