Abstract
The wire-bonding method for electrically connecting the substrate and the electrode pads is used for mounting semiconductor components on circuit boards. However, as wire pitch becomes narrower in advanced packaging, the flip chip method has drawn attention as a means of mounting the chip by direct connection to the circuit board. In general, circuits are formed by sputtering aluminum onto an organic insulating film, which is then plated using a double-zincate method. However, for aluminum electrodes on polyimide, the polyimide is attacked by the strong alkaline or acid zincate bath. In this article, a zincate-free process on aluminum and wiring pattern formation on polyimide proved the possibility of using a combined treatment of fine Ni particle formation with direct electroless NiB plating and thick electroless NiP plating.
