Load sensitive stable current source for complex precision pulsed electroplating

Electrodeposition is a highly versatile and well explored technology. However, it also depends strongly on the experience level of the operator. This experience includes the pretreatment of the sample, and the composition of the electrolyte settings of the plating parameters. Accurate control over the electroplating current is needed especially for the formation of small structures, where pulsed electrodeposition has proven to reduce many unwanted effects. To bring precision into the formation of optimal recipes, a highly flexible current source based on a microcontroller was developed. It allows a large variety of pulse waveforms, as well as maintaining a feedback loop that controls the current and monitors the output voltage, allowing for both galvanostatic (current driven) and potentiostatic (voltage driven) electrodeposition. The system has been implemented with multiple channels, permitting the simultaneous electrodeposition of multiple substrates in parallel. Being based on a microcomputer, the system can be programmed using predefined recipes individually for each channel, or even adapt the recipes during plating. All measurement values are continuously recorded for the purpose of documentation and diagnosis. ... mehrThe current source is based on a high power operational amplifier in a modified Howland current source configuration. This paper describes the functionality of the electrodeposition system, with a focus on the stability of the source current under different electrodeposition current densities and frequencies. The performance and high capability of the system is demonstrated by performing and analyzing two nontrivial plating applications.