Chemical Dry etching can improve adhesion of coatings, adhesives or varnish a lot. In some cases etching has the function of a activation, particularly in case of etching PTFE. In most cases however the essential effect of plasma etching is increasing the effective adhesive surface.
For optimal etching the process parameters need to be optimized experimentally, because in most cases there is a distinct optimum of effectiveness. In many cases too intensive etching, particularly too long etching reduces the adhesion. To intensive ectching damages the surface of a substates. This effect is designated "overetching".