Influence of plasma treatment on the improvement of surface energy [packaging]

Surface treatment is increasingly important in electronic packaging. Reasons for this development are increasing demands on the reliability of component packaging and the application of different materials with either high-energy or low-energy surfaces. High-energy materials include metals, metal oxides and inorganic compounds. Low-energy materials include organic materials and water. The surface tension of a liquid or the surface energy of a solid material is a key factor to the quality and reliability of electronic packaging. It influences the wettability, spreading and adhesion of polymers and metals. Good wettability during soldering or good adhesion between polymer tapes depends on the surface finish. For example, oxide layers and organic contamination lead to a lower surface energy of metals. The surface energy of a solid material can be influenced by chemical, thermal and mechanical methods. The influence of plasma treatment on the surface energy of solid materials is under investigation at the Electronics Technology Laboratory. Surface energies calculated on the base of measuring the contact angle are determined and the differences between untreated and plasma-treated materials are discussed. Conclusions can be drawn about the wettability and adhesion of the surfaces. The paper presents a short overview of the theoretical fundamentals of contact angle measurement and surface energy as well as practical results with different materials.