About N. G. Sarius

SP Technical Research Institute of Sweden, Borås, Sweden / Thin Film Physics Division, Department of Physics, IFM, Linköping University, Sweden

Electroplating of Nickel in Grooves Under the Influence of Low and Medium Frequency Ultrasound

The effect of ultrasonics on filling properties has been studied by Ni electroplating from a sulphamate electrolyte in high aspect ratio grooves. Experiments were carried out with two different modes of ultrasound: a) 25 kHz ultrasound with an effect of 225 W directed perpendicular to the substrate surface; b) ultrasonic standing waves of 100 kHz and 400 kHz parallel to the substrate surface. It was found that both methods improve filling in grooves that are between 0.35 and 1 mm wide with aspect ratios between 0.6 and 3, compared to electroplating with conventional agitation. Under the investigated conditions, the 400 kHz standing wave parallel to the surface was most efficient to improve filling of grooves.