Inline Process Refractometer For Semiconductor Industry

The SCHMIDT + HAENSCH iPR S inline process refractometer continuously measures refractive index and temperature in semiconductor wet chemical processes. Real-time data from the process liquid helps operators monitor chemical composition and identify deviations from defined operating conditions. For specific liquids, measurement values can be converted into concentration data using application-specific correlations. With an accuracy of ±0.0002 RI, the iPR S supports precise process monitoring. Sapphire and PFA wetted materials address demanding chemical compatibility requirements, while Flare and PrimeLock® connections facilitate integration into existing systems. From chemical blending and dosing to wafer cleaning, wet etching and chemical mechanical planarization (CMP), the iPR S provides continuous measurement information to support stable operating conditions and process control.

Checkpoints

  • Developed specifically for semiconductor wet chemical processes
  • Continuous refractive index and temperature measurement directly in the process liquid
  • Real-time measurement data for monitoring chemical composition and identifying process deviations
  • Refractive index accuracy of ±0.0002 RI for precise process monitoring
  • Measuring range from 1.3200 to 1.5100 RI, extendable to 1.5300 RI on request
  • Sapphire and PFA wetted materials for demanding semiconductor process environments
  • Flare and PrimeLock® connections for ¼”, ⅜”, ½”, ¾” and 1″ tubing
  • Process temperatures from -20 to +90 °C and pressures up to 6 bar, with up to 10 bar on request
  • Application-specific concentration monitoring for defined process liquids using validated correlations
process solutions

Easy to Use

The iPR S is designed for integration into semiconductor wet chemical installations. Flare and PrimeLock® connections for tubing sizes from ¼” to 1″ provide flexibility when incorporating the refractometer into process systems. The combination of sapphire and PFA wetted materials supports applications where chemical compatibility and contamination risks require careful consideration. Once integrated into a suitable process line, the iPR S continuously measures refractive index and temperature directly in the liquid. Available output parameters include refractive index, temperature and concentration (wt%), with concentration determination based on an appropriate application-specific correlation. For convenient configuration and measurement monitoring, SCHMIDT + HAENSCH provides the UniConfig Windows PC software, which allows users to adjust instrument settings, view live measurement values and record data for further evaluation. Continuous measurement data provides additional information for process monitoring between laboratory measurements.

Applications

The iPR S is designed for semiconductor wet chemical processes where changes in liquid composition must be monitored. Potential applications include bulk chemical delivery, chemical blending and dosing, wafer cleaning, wet etching, post-etch residue removal and chemical mechanical planarization (CMP). In CMP slurry preparation and distribution, continuous refractive index and temperature measurements help identify composition changes associated with hydrogen peroxide (H₂O₂) dosing and dilution. Selective H₂O₂ concentration determination requires verification for the specific slurry formulation because other components also influence refractive index. In silicon wet etching, the iPR S can support KOH concentration monitoring. Changes caused by evaporation or dissolved silicon species can be monitored using a suitable process-specific correlation that accounts for their influence. For post-etch residue removal with EKC® chemicals, continuous measurements can help monitor variations in water content when a validated correlation is available for the specific cleaning formulation. These measurements support more consistent chemical conditions during wafer processing.

Product in depth

The iPR S measures refractive index and temperature continuously in semiconductor process liquids. Because refractive index depends on both chemical composition and temperature, the measured values provide information about changes in the process medium. With an application-specific correlation, refractive index and temperature can be used to determine concentration in weight percent (wt%) for defined liquid compositions. The refractometer covers a standard measuring range of 1.3200 to 1.5100 RI, with an accuracy of ±0.0002 RI. It operates at process temperatures from -20 to +90 °C and features a temperature sensor accuracy of ±0.1 °C. Sapphire and PFA wetted components, combined with a housing made from PVDF and PEEK, provide a material configuration designed with semiconductor wet chemical installations in mind. Flare and PrimeLock® connections support integration into different process-line configurations.

In Practice

In semiconductor manufacturing, maintaining defined chemical conditions is essential for process stability and repeatability. The iPR S provides continuous refractive index and temperature measurements, allowing operators to follow changes in process-liquid composition between individual laboratory measurements. During chemical blending and dosing, the measurement data can help identify dilution deviations and other composition-related changes. In wet etching applications, continuous measurements support the monitoring of chemical conditions that may vary through evaporation or the accumulation of reaction products. For processes requiring concentration values, the relationship between refractive index, temperature and chemical composition must be established for the specific application. This is particularly important for multicomponent process liquids, where several substances can influence the measurement. Laboratory reference analysis remains valuable for verifying concentration correlations and interpreting process changes. By combining continuous inline measurements with application-specific evaluation, the iPR S supports more informed decisions and reliable monitoring of semiconductor wet chemical processes.

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