Improved adhesion of DLC films on copper substrates by preimplantation

•Improved adhesion of DLC films on copper substrates by implantation pretreatment•For − 10 kV implantation best result with mixture of O2 and N2•Highest adhesive strength for oxygen implantation is with − 15 kV•Values for adhesive strength mostly in the range 10–15 MPa•Effect mainly due to surface cleaning and roughening by implantation

The adhesion of diamond-like carbon (DLC) films on copper substrates is usually very poor. However, the adhesive strength of the films can be improved by a preimplantation step. With plasma based ion implantation and deposition, the preimplantation step and the film deposition can be realized with the same experimental setup. The effect of the implantation of several different gaseous species (N2, O2, Ar, CO2, C2H4, and air) at − 10 kV was investigated. For O2, N2 and C2H4 the influence of the pulse voltage (− 5, − 10, − 15 kV) was examined. The samples were characterized by elemental depth profiling (XPS, SIMS), and the adhesion was evaluated with a pull tester.Most of the preimplantation treatments increase the adhesion of the DLC films on the copper substrates considerably to values of 10–15 MPa. The best result was obtained with − 15 kV oxygen preimplantation.