Trace Water Measurement in Organic Solvent Systems for Semiconductor Manufacturing
ABSTRACT
The control and measurement of trace water in organic solvent systems is a fundamental yet often under-recognized determinant of surface preparation, cleaning efficiency, and overall process reliability in semiconductor manufacturing. While water in aqueous systems behaves as a continuous bulk phase, water present at trace levels in organic solvents exhibits distinctly different physicochemical behavior. In organic solvent media, disruption of extended hydrogen-bonding networks leads to a higher fraction of molecularly dispersed or weakly associated H₂O, resulting in disproportionate interfacial and electrochemical effects compared with bulk aqueous systems.
These effects accelerate corrosion mechanisms by increasing electrolyte conductivity and interfacial reactivity, intensify solvent–surface interactions, increase reaction kinetics, and influence drying and mass-transport behavior. In advanced manufacturing environments, such changes can trigger unexpected process excursions, degrade sensitive materials, reduce yield, and accelerate equipment aging if trace water is not continuously and accurately monitored. Resist strippers typically contain solvents such as linear and cyclic ketones (e.g., acetone, NMP), amides, and sulfoxides. Common additives include amines, quaternary amine hydroxides such as TMAH, and halogen-containing compounds. Polar solvents, including DMSO and diethylene glycol monobutyl ether, readily absorb moisture, which can be detrimental to wafer integrity.
Accurate water quantification in these matrices is challenging, as Karl Fischer measurements can be significantly affected by interfering components, particularly strong bases such as TMAH. To address these challenges, CI Semi has developed NIR-based online trace water measurement methods tailored to different solvent matrices. In this approach, a sample-specific Karl Fischer method is first developed and used as an independent reference for NIR model development and validation. Once established, the NIR method enables reliable online monitoring, supporting improved process control in solvent handling and wafer surface preparation processes.
This presentation will:
- Explain the physicochemical distinction between bulk water and trace water in organic solvent systems and its impact on process behavior.
- Illustrate the manufacturing risks associated with increased water activity at ultra-low concentrations, including corrosion and surface instability.
- Describe automated NIR-based measurement approaches developed by CI Semi for trace water monitoring, supported by matrix-specific Karl Fischer methods used for reference and validation.
- How measurement validity is verified — method verification in an automatic analyzer.
- Demonstrate how advanced water monitoring supports contamination control, yield stability, and equipment protection in semiconductor surface preparation and cleaning processes.
This work reinforces that trace water is not merely a residual impurity, but a high-impact process parameter requiring advanced analytical techniques and automated control, directly aligned with SPCC priorities in contamination monitoring, analytical innovation, and process reliability.
BIOGRAPHY
Dr. Dana Shoken is an R&D Manager at CI Semi with a strong background in analytical chemistry and analytical instrument development. She holds a Ph.D. in Chemistry from the Technion and brings over a decade of experience across academic research and industrial R&D.
Dr. Shoken’s background spans organic and inorganic synthesis, formulation chemistry, method development, and data analysis, with hands-on experience in building practical measurement strategies under real-world constraints. At CI Semi, she applies this foundation to process monitoring challenges, bridging fundamental analytical chemistry with emerging needs in advanced manufacturing environments.