Plasma Processing and Polymers: A Personal Perspective

Low-temperature plasma science and technology has made enormous strides during the past half-century. To a significant extent, the driver has been integrated circuit (IC) processing, because without plasma-based etching and deposition techniques, the progression of Moore's law would have ceased its course long ago. Scientific and technological advances no less spectacular than those in the IC sector, and of comparable economic impact, have occurred in the area of plasmas and polymers, where a third process type, surface modification, can be added to those, etching-or ablation, and deposition, mentioned above. In this article, we start by listing a number of particular features associated with the exposure of polymers to low-temperature plasmas, for example the liberation of volatile molecular fragments from the surface due to bond scissions, the accompanying creation of free radicals, cross-linking and grafting reactions induced by this and by vacuum-ultraviolet photon irradiation from excited species in the plasma, etc. All these aspects are of far lesser impact, if any at all, when the same plasmas are in contact with inorganic surfaces. We then list some high-volume industrial processes and operational details drawn from diverse economic sectors. These are accompanied by detailed example-cases from our own laboratories, based on both low- and atmospheric-pressure low-temperature plasma processes.