Influence of pulse-plating on internal stresses of alloy deposits and multilayers

摘要

Some alloy systems are showing high internal stresses - compressive or tensile - when electrodeposited at direct current. These internal stresses can possibly be strongly reduced by modifying the applied current form in an appropriate way, e.g. using zero current phases or anodic pulses during electrodeposition. Metallic multilayer systems - like cobalt-gold, silver-copper, cobalt-platinum etc. - are electrodeposited by alternating the parameters current density, potential or hydrodynamics. By selecting suitable deposition parameters, the total internal stress of a multilayer system can be put to a minimum. For example, at two different current levels, both compressive and tensile stresses can be generated. In total, the two types of stresses can compensate each other. To be able to immediately assess the effects of parameter variations, FEM has recently developed an instrument to in-situ determine internal stresses, called MSM 200. The paper will show with some examples the potentialities which open up using pulse-plating for electrodepositing alloys or multilayers with reduced internal stresses.