Effects of pulse reverse electroforming parameters on the thickness uniformity of electroformed copper foil

Abstract

ABSTRACTThe non-uniformity of electroformed layers directly affects the mechanical properties and application requirements of micro devices. Therefore, uniformity of electroformed copper foil is significant in ensuring or improving the mechanical properties of micro devices. The influences of duty cycle, current density, power source, and electroforming time on the thickness uniformity of electroformed copper layers were studied, and these parameters were optimised by using the orthogonal experiment method. The thickness distribution rule of electroformed copper foil was also determined. Duty cycle had the largest influence on the uniformity; the uniformity of electroformed layers prepared with pulse reverse current power source was superior to those prepared with direct current power source and pulse current power source. Increasing current density enhanced uniformity. The optimal technical process suggested by this orthogonal experiment adopts pulse reverse current power, 30% of positive duty cycle, 10% of negative duty cycle, 2 A dm−2 of current density, and 92 minutes of electroforming time. The minimum coefficient of variation reached 1.54%. The thickness of electroformed copper foil varied directionally.