Automated CVS Method Development and Optimization of Multicomponent Plating Baths

Automated CVS Method Development for Multicomponent Copper Plating Baths

Significance of Topic

The cyclic voltammetric stripping (CVS) and cyclic pulse voltammetric stripping (CPVS) techniques are central to quantifying organic additives in acid copper plating baths used in printed circuit board and semiconductor wafer production. As additive formulations evolve into more complex three-component systems (suppressor/carrier, accelerator/brightener, leveler), robust analytical routines become essential for maintaining deposit quality, process reproducibility and regulatory compliance.

Objectives and Study Overview

This study demonstrates an automated, software-driven approach for method development and optimization of multicomponent copper plating baths. Two chemically distinct plating formulations were analyzed to illustrate challenges in suppressor, brightener and leveler quantification. Emphasis was placed on assessing how hardware advances (automated dosing, pump station, sample changer) and viva software features (method editor, sample data variables, determination series) accelerate data collection and method robustness testing.

Methodology

The workflow combines classical electroanalytical techniques with automation:

• Suppressor quantification via Dilution Titration (DT): incremental standard additions and measurement of stripping peak charge (Q) under defined rotation speed and vertex potential.
• Brightener analysis by Modified Linear Approximation Technique (MLAT): creation of an intercept solution, standard additions of accelerator to assess linear Q response, and selection of optimal CVS or CPVS parameters.
• Leveler determination through Response Curve (RC) technique: calibration of leveler-free electrolyte containing established suppressor and brightener levels, followed by comparison of sample response.

Each step exploits viva’s sample data variables for systematic variation of parameters (rotation speed, first vertex potential, plating time) and uses automated determination series to generate calibration or linearity data without manual intervention.

Instrumentation Used

• Metrohm 894 Professional CVS System with rotating disc electrode configuration
• 858 Professional Sample Processor (optional high-throughput autosampler)
• Dosinos for precision dispensing of standards, bath make-up and synthetic samples
• 843 Pump Station for automated rinsing, drainage and cleaning of the measuring cell
• viva software for method editing, sequence control and data evaluation

Main Results and Discussion

Suppressor curves obtained by DT revealed bath-dependent shifts in evaluation points and highlighted the influence of rotation speed and first vertex potential on peak height. Brightener linearity studies showed that CPVS extended the linear Q response to higher additive concentrations compared to CVS, allowing larger sample volumes and reduced dilution error. Response Curve calibration for leveler exposed significant differences in slope between the two bath chemistries, underlining the need for tailored sweep settings. Automated synthetic bath additions and sequence control in viva enabled rapid robustness testing across multiple operating conditions.

Benefits and Practical Applications

• Higher throughput and reproducibility via unattended determination series
• Reduced reagent consumption and waste using automated dosing of synthetic samples
• Flexible method optimization through systematic parameter variation
• Improved confidence in process control for plating bath suppliers and end-users
• Easier transfer of validated methods across laboratories

Future Trends and Applications

The next generation of electroanalytical method development will integrate machine-learning algorithms to predict optimal sweep parameters and additive interactions. Inline, real-time monitoring with miniaturized CVS sensors may enable continuous quality control in plating lines. Further advances in software orchestration and digital twin simulations will reduce experimental workload and deliver faster response to evolving bath formulations.

Conclusion

The combination of Metrohm’s automated hardware and viva software transforms the labor-intensive development of multicomponent plating bath analyses into a streamlined, reproducible process. By leveraging Dilution Titration, MLAT and Response Curve techniques under automated control, users can efficiently tailor methods to diverse chemistries, ensure robust performance and maintain stringent quality standards.

References

1. Kubicsko M.; Vyas R. Automated CVS Method Development and Optimization of Multicomponent Plating Baths. Metrohm White Paper WP-051EN, 2019.