Copper electrodeposition into macroporous silicon arrays for through silicon via applications

The present paper deals with the formation of high conductivity through silicon via from macroporous silicon arrays. The through wafer macropores were first etched by anodization into a hydrofluoric acid – ethanol mixture. The conditions of straight and ordered macropore etching were studied. The high aspect ratio (18) and high density via (above 105/cm2) were then filled by copper using an optimized potentiostatic technique involving a specific electrolyte with additives. The copper micro-wires were observed by SEM whereas XRD analysis enabled the determination of the average grain size.