By means of dry etching, the adhesiveness of a bonded joint or a printed or painted coat can be significantly improved. In individual cases, etching serves the purpose of activation, in particular in case of etching of PTFE, which removes fluorine radicals from the surface. In most cases, however, the increase in adhesiveness is achieved by increasing the wettable surface. Tests must be carried out to determine the parameters which yield an optimal treatment result, in particular the duration of treatment. For many substrates, it is absolutely not true that the longer the treatment is carried out, the better the result. Excessively long and overly intensive plasma treatment results in increasing decomposition of the surface of the substrate. This is called “overetching”. The term “underetching“ refers to a completely different process and is certainly not the opposite of overetching.