Laser reinforcement of polytetrafluorethylene-metal adhesive joints

Abstract

Summary form only given, as follows. Adhesion between polytetrafluorethylene (PTFE) and metals is rather poor. In this paper an original method for solving the problem of adhesion between PTFE and copper vacuum deposited film is proposed. This method consists of exposing the adhesive joint from the side of the copper film to pulsed laser emission with alternating duration. The attained adhesive strength of the PTFE-copper joint is comparable with cohesive strength of bulk PTFE. The causes of adhesion strengthening of the joint are discussed on the basis of atomic force microscopy (AFM), SEM, and SIMS. It is probable that reinforcement of the PTFE-copper joint after laser treatment results from pulsed heating of the PTFE boundary layer which is interfaced to copper and activation of the adhesive interaction in the presence of oxygen sorbed by metal. It is supposed that this is a necessary condition for reinforcement of the joint. The data obtained deepen our insight on the adhesive interaction in metal-polymer systems under laser treatment. In practice these results might be used for metallic film soldering on polymeric substrates in microelectronics.