Inline measurement for critical cleaning and etching processes
The focus is on classic and modified SC1 and SC2 chemistries in wafer production, specifically NH₄OH / H₂O₂ / H₂O or HCl / H₂O₂ / H₂O, not only in standard approaches, but also in process-specific dilutions, concentration windows and adapted formulations, e.g. with TMAH. The same applies to BOE (or BHF) based on HF and NH₄F, where even minor deviations can influence the etching rate, selectivity and process stability. The new sensor was designed precisely for these chemically sensitive wet processes
The everyday challenge: monitoring process chemistry reliably and economically
The target group is primarily semiconductor manufacturers, operators of wet benches and wet process systems as well as process, equipment, integration and quality engineers who need to ensure chemical process stability in cleanrooms. Their daily work is characterized by narrow process windows, high quality pressure, limited space in the cleanroom and the need to monitor chemical compositions without additional sampling or manual handling. Although inline analysis solutions already exist for these tasks, they are often based on more complex measuring methods and are correspondingly demanding in terms of integration and operation. This is precisely where the new sensor comes in: Instead of relying on time-delayed laboratory analyses or complex analytics, information on the respective concentration is available directly in the process
Ultrasonic-based, temperature-compensated and prepared for uncomplicated integration
The SensoTech solution uses the ultrasonic transit time or the specific sonic velocity in the medium as the central measured variable for determining the concentration. Depending on the medium and process, this measuring principle can be combined with other parameters such as conductivity or other process-relevant variables. The system combines the available measurement signals, compensates for temperature influences and calculates the relevant concentration information in real time. This creates a flexible measurement architecture for different wet processes without complicating integration. The system is completely maintenance-free, requires no consumables and can be integrated into existing automation environments via standard interfaces.
More control over critical wet processes
The new solution is particularly relevant wherever stable chemical concentrations directly determine process quality and system availability. In SC1 and SC2 baths, this concerns reliable compliance with specified recipes, and in BOE processes it also concerns the precise control of a particularly sensitive etching medium. Continuous concentration monitoring creates a reliable data basis for detecting process deviations at an early stage, evaluating bath service life in a more targeted manner and better adapting maintenance and chemical management interventions to the actual process status.
Direct benefits for production and process management
For operators of wet process systems, this primarily means greater reliability in daily process management. Concentration curves become transparent, process windows can be kept more stable and changes in the bath condition can be evaluated earlier. This supports reproducible system operation, reduces unnecessarily conservative bath changes and improves the basis for quality assurance, documentation and ongoing process optimization.
About SensoTech
SensoTech GmbH develops and produces sensors and measuring systems for the inline analysis of liquids in industrial processes. The focus is on measuring concentration and density in real time, directly in the pipe or in the process. The systems are also suitable for challenging media such as acids, alkalis or solvents and help to improve process safety, product quality and efficiency.
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Further links
👉 www.sensotech.com/de/halbleiterindustrie
Photo: SensoTech GmbH
