Determination of suppressor in acid copper baths by smartDT

Significance of the Topic

The precise measurement of suppressor concentration in acid copper plating baths is critical for maintaining deposit quality and process stability in electroplating industries. Traditional dilution titration methods require many reagent additions and prolonged analysis time. The smartDT approach optimizes addition steps, reducing both the number of operations and total assay duration while preserving analytical accuracy.

Objectives and Study Overview

This application note evaluates a novel titration routine (smartDT) for rapid determination of suppressor levels in acid copper baths. The study compares classical dilution titration (DT) with smartDT regarding accuracy, number of additions, and total analysis time. Key performance metrics include recovery of a check standard and time saving per determination.

Methodology and Instrumentation

The method employs cyclic voltammetry semiautomated titration with a customized software algorithm to calculate variable addition volumes. The operator sets the largest and smallest addition steps; the software dynamically adjusts intermediate volumes based on the titration progress toward a fixed evaluation ratio (0.5). Peak potential is monitored at 0.2 V against a horizontal baseline.

Used Instrumentation

• 894 Professional CVS semiautomated titrator (viva).
• Rotating disk electrode (RDE) assembly.
• 2 mm platinum tip working electrode.
• Ag/AgCl/KCl (3 mol/L) reference electrode with KNO₃ bridge electrolyte (1 mol/L).
• Separate platinum rod counter electrode.

Key Results and Discussion

Comparison of a 3 mL/L suppressor check standard yielded 3.02 mL/L by classic DT and 3.04 mL/L by smartDT (recoveries of 100.7% vs. 101.3%, respectively). The number of additions dropped from 14 to 8 with smartDT. Both workflows required 7 minutes for initial setup, but smartDT reduced titration time from 28 minutes to 16 minutes, delivering a total analysis time of 23 minutes versus 35 minutes—a 34% time saving.

Benefits and Practical Applications

• Accelerated analysis throughput for routine bath control.
• Maintained or improved accuracy compared to classical methods.
• Lower reagent consumption and reduced operator workload.
• Easy integration into existing semiautomated systems.

Future Trends and Opportunities

• Expansion of smartDT algorithms to additional plating additives and bath chemistries.
• Integration with laboratory information management systems (LIMS) for real-time process feedback.
• Development of AI-enhanced titration control for predictive maintenance and adaptive sampling.
• Miniaturization and field-deployable versions for on-site quality control.

Conclusion

smartDT demonstrates significant time savings and robust analytical performance for suppressor determination in acid copper baths. Its variable addition strategy streamlines titration workflows without compromising accuracy, offering a valuable tool for electroplating quality control laboratories.

References

• VA Application Note V–202: Determination of suppressor in acid copper baths by smartDT.