Redistribution Layer Preparation on Glass Panel for Panel Level Fan Out Package by Photosensitive Polyimide

We successfully developed redistribution structure by using photosensitive polyimide and all wet Cu plating processes. To obtain the structure, patterned Cu was obtained by non-electrical plating on photosensitive polyimide layer with a mask of photo-resist. Various types of surface treatments on polyimide layer were investigated to obtain good adhesion between Cu and polyimide. In this work, we coated the photosensitive polyimide by a slit coater and found a suitable wet surface treatment to obtain good adhesion to plated Cu. The all wet Cu processes are composed of wet activation process and electro-Cu plating process. By combining all these processes, 40μm line and space Cu pattern was obtained by using a 500-600 mm glass panel. In addition, 2μm line and space Cu pattern was obtained on an 8 inch glass wafer.