In semiconductor manufacturing, reliable, controlled wet processes determine yield, quality, and reproducibility. Especially in process steps such as SC1, SC2, or BOE (Buffered Oxide Etch), chemical concentrations must be maintained precisely because even small deviations can negatively affect cleaning and etching results. With a new sensor specially designed for the semiconductor sector, SensoTech is now bringing an ultrasonic solution to the market that enables these concentrations to be monitored directly inline and in real time.
The focus is on classic and modified SC1 and SC2 chemistries in wafer manufacturing, specifically NH₄OH / H₂O₂ / H₂O and HCl / H₂O₂ / H₂O, not only in standard formulations but also in process-specific dilutions, concentration ranges, and adapted recipes, e.g. with TMAH. The same applies to BOE (or BHF) based on HF and NH₄F, where even small deviations can affect the etch rate, selectivity, and process stability. The new sensor was designed precisely for these chemically sensitive wet processes.
The target group primarily includes semiconductor manufacturers, operators of wet benches and wet process systems, as well as process, equipment, integration, and quality engineers who must ensure chemical process stability in the cleanroom. Their daily work is characterized by narrow process windows, high quality pressure, limited space in the cleanroom, and the need to monitor chemical compositions with as little additional sampling or manual handling as possible. Inline analysis solutions already exist for these tasks, but they are often based on more complex measurement methods and are correspondingly demanding in terms of integration and operation. This is exactly where the new sensor comes in: instead of relying on delayed laboratory analyses or complex analytics, information on the respective concentration is available directly within the process.
The system combines the available measurement signals, compensates for temperature effects, and calculates the relevant concentration information from them 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 common interfaces.
The solution is particularly relevant wherever stable chemical concentrations directly determine process quality and system availability: in SC1 and SC2 baths, it supports the reliable maintenance of specified recipes; in BOE processes, the precise control of a particularly sensitive etching medium. Continuous concentration monitoring provides a reliable data basis for detecting process deviations at an early stage, evaluating bath service life more accurately, and aligning maintenance and chemical management more closely with the actual process condition.
For operators of wet process systems, this means greater reliability in day-to-day process control: concentration trends become transparent, process windows are maintained more consistently, and changes in bath condition are assessed earlier. This supports reproducible system operation, reduces unnecessarily conservative bath changes, and improves quality assurance, documentation, and ongoing process optimization.
