Selective plasma etching of micro and nano polymer-matrix composites

Abstract

Summary form only given. Selective etching technology has been developed for selective removal of surface layer of polymer on micro and nano polymer matrix composites, leaving fillings virtually intact. This technology is useful for the coatings and composite industry for quality control of the product or in electronic industry for developing new nano-based sensor devices, and also elseware. The two methods for selective etching were developed, compared and evaluated; selective oxygen plasma etching and laser ablation selective removal. In order to avoid neutral gas heating, plasmas are often created in high frequency discharges. Characteristics of plasmas used in different technologies depend on the nature of the material treated. Many applications require plasma with a high degree of ionization, while some prove better if weakly ionized plasma is used. Modern reactors for cold plasma ashing, for instance, use post-glows for sample treatment rather than plasmas themselves. A modern technique based on application of weakly ionized plasma is selective etching of composite materials. It is based on preferential etching of different composite ingredients. High etching selectivity is obtained due to different probability for oxidation with O atoms for different materials. Many materials are not etched at all - grains of ceramics, glasses and some metals, for instance. Carbon of other fillings including nanowires are etched according to the material binding energy - the etching efficiency increases in the range from diamond, graphite, crystalline and amorphous polymer. Even different types of polymers are etched also at different rates. Similarly, limited selective removal can be achieved on the surface of polymer matrix composite with laser ablation, due to selective interaction of light quanta with material, depending on pulse energy and wavelength selection.