Surface contamination effects on film adhesion on metals and organic polymers

Three examples of contamination induced delamination of vacuum-deposited films are cited to stress the necessity for identifying substrate surface contaminants, and then removing them from the surfaces prior to film deposition with an effective cleaning procedure, or preventing them from contacting the substrate surface, or eliminating their source during the polymer manufacture. The major contaminate that caused film delamination is polydimethylsiloxane (polydimethylsilicone) (PDMS) and/or its oligomers. This polymer (and its oligomers) has (have) a low glass temperature (−44 °C) that enables it to diffuse into the pore structure of the free volume of polymer substrates at ambient temperature. Once entrapped in the pores, it cannot be removed by non-swelling organic or inorganic solvents but only by plasma etching.