Plasma process considerations in emerging semiconductor packaging technologies

Plasma cleaning technology is a well known method of contamination removal and surface activation to enhance the performance and reliability of advanced semiconductor packages. It has also gained widespread acceptance and implementation over the last 10 years. With the continued introduction of new packaging technologies and materials, the applications for plasma technology have also broadened. This paper will review the considerations and performance benefits of employing plasma technology in flip chip, copper wirebonding and LED lens molding applications. The importance of using the optimum combination of process parameters and plasma technology in conjunction with different combination of materials will be the key underlying theme. This will be clearly illustrated firstly with a flip chip application example where the correct gas chemistry is shown to be important in achieving the desired adhesion and reliability characteristics in a flip chip underfill process. Quantitative data obtained from field studies will also be presented to show how plasma treatment can enable the realization of the low-cost benefits of copper wirebonding. Also discussed will be how the advantages of inline type plasma over a batch type system can produce significantly improved wirebond results. Finally, we will discuss how the adhesion promotion ability of plasma treatment enables the high-volume, low cost production of molded silicone LED lenses.