Real-time monitoring of additive concentrations in acidic copper plating solution is critical for ensuring process stability and reliability in integrated circuit manufacturing. Traditional detection systems rely on bulky platinum rotating disk electrodes (2–3 mm diameter) that consume large solution volumes to maintain unrestricted flow at high speeds, complicating operational workflows and limiting miniaturization. A team of scientists has addressed these challenges by developing a novel electrochemical microfluidic workstation that combines 3D-printed microfluidic chips with static platinum ultra-microelectrodes. By integrating microfluidic programmed mixing, the system reduces single-test solution consumption to 220 microliters. Calibration curves based on additive effects on copper deposition kinetics enable concentration detection with average relative errors below 10%. Their work is published in the journal Industrial Chemistry & Materials on June 26.
"We aim to equip acidic copper plating solution with a 'Fitness Tracker' to enhance process stability and reliability," explains Lianhuan Han, an associate professor at Xiamen University. The electrochemical microfluidic workstation can serve as a 'Fitness Tracker' for acidic copper plating solution, enabling continuous monitoring of additive concentrations to ensure operational stability and reliability. The research team integrated microfluidics with ultramicroelectrodes to fabricate an electrochemical microfluidic workstation. This automated system enables online monitoring of suppressor, accelerator, and leveler concentrations in acidic copper plating solution.
Real-time monitoring of additive concentrations in acidic copper plating solution is a critical technology for ensuring process stability and reliability in copper interconnect fabrication for advanced integrated circuit manufacturing. Conventional analytical instruments for additive concentration detection typically employ platinum rotating disk electrodes (2–3 mm in diameter) as working electrodes, which require large solution volumes to maintain unrestricted electrolyte flow at high rotational speeds for enhanced mass transfer efficiency. However, these requirements complicate solution preparation procedures and severely limit the miniaturization, cost-effectiveness, and portability of analytical systems.
Static ultramicroelectrodes offer distinct advantages due to their diminutive size, including low capacitance, negligible IR drop, accelerated mass transfer rates, and superior signal-to-noise ratios. Compared to rotating disk electrode systems requiring dedicated rotators and speed controllers, ultramicroelectrodes facilitate greater system miniaturization at significantly reduced costs. The research team utilized 3D printing technology to rapidly fabricate microfluidic chip molds. Microfluidic devices were subsequently manufactured through a process involving casting polydimethylsiloxane (PDMS) prepolymer onto the 3D-printed molds, followed by thermal curing, physical drilling, oxygen plasma bonding, and integration with platinum ultra-microelectrodes. The developed electrochemical microfluidic workstation achieves a solution consumption of 220 μL per single detection cycle while maintaining an average relative error below 10%, meeting the stringent requirements of industrial production lines. The work addresses critical industrial needs for process miniaturization, cost efficiency, and detection accuracy in semiconductor manufacturing environments.
Looking ahead, the research team anticipates that their work will provide theoretical foundations for developing portable detection instrumentation to broaden application scenarios for additive concentration monitoring. "Our next step focuses on expanding the application scope of this device to ultimately achieve industrial-scale implementation," stated Professor Han. "We envision significant potential for this platform in diverse additive concentration detection scenarios across multiple industrial sectors."
The research team includes Yi Zhao, Ju-Xing Zeng, Jia-Qiang Yang, Tao Song, Ren Hu, Jian-Jia Su, Bo Zhang, Fang-Zu Yang, Dongping Zhan and Lianhuan Han from Xiamen University.
This research is funded by the National Natural Science Foundation of China and National Key Research and Development Program of China.
Industrial Chemistry & Materials is a peer-reviewed interdisciplinary academic journal published by Royal Society of Chemistry (RSC) with APCs currently waived. ICM publishes significant innovative research and major technological breakthroughs in all aspects of industrial chemistry and materials, especially the important innovation of the low-carbon chemical industry, energy, and functional materials. Check out the latest ICM news on the blog .
