Concentration measurement
in the
semiconductor industry
in the
semiconductor industry
Concentration monitoring for semiconductor processes – for efficient production, stable processes, and highest quality.
±0.02 wt% Accuracy
Real-time measurement
Maintenance-free
Cost saving
Challenges in concentration measurement in semiconductor processes
In semiconductor manufacturing, precise chemical concentrations are crucial, but traditional lab analyses often deliver results too late. With LiquiSonic® SensoTech enables reliable real-time monitoring that can be easily integrated into existing processes. The system delivers precise measurement data maintenance-free, thereby increasing process safety and efficiency.
Challenges
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Chemical concentrations not within target range
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Time-consuming laboratory analyses
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No immediate and reliable information on chemical composition
Solution: LiquiSonic®
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Clear monitoring with LiquiSonic®
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Immediate display of chemical concentration
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Seamless integration into existing systems
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Maintenance-free and without consumables
Your advantages
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Traceable and reliable measurement results
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Measurement results in real-time
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Completely maintenance-free sensors and chemical-resistant materials
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Easy integration into systems of any size and configuration
Our solution: The LiquiSonic® Measurement system
Monitor concentration in real-time
LiquiSonic® combines modern ultrasonic technology with temperature-compensated measurement to deliver precise results in critical chemical mixtures in semiconductor manufacturing. Real-time monitoring ensures stable product quality, reduces deviations, and provides data for process optimizations. This reduces operating costs and chemical consumption while increasing process safety and efficiency.
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Ensure quality: Real-time monitoring guarantees precise results without deviations.
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Reduce costs: Less chemical consumption and reduced operating costs.
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Increase efficiency: Optimized processes for maximum reliability in semiconductor manufacturing.
Technical details and specifications
Ultrasonic measuring principle
The speed of sound in liquids is directly related to the concentration of dissolved substances. High-precision time measurements allow for exact determination of concentration.
Conductivity integration
In three-component systems, conductivity is used as a second physical parameter to clearly determine both concentrations.
Temperature compensation
Two PT1000 sensors integrated into the measuring cell ensure automatic temperature compensation, providing precise measurements under all conditions. By directly capturing the process temperature, the speed of sound is corrected in real time, improving stability and accuracy even with fluctuations.
Economic benefits
Real-time concentration measurement increases Quality, efficiency, and reliability, while simultaneously Reducing costs and resource consumption:
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Reduced operating costs through reduced chemical consumption and fewer laboratory analyses
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Less waste and rework, as deviations can be detected and corrected immediately
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Stable product quality ensures competitiveness and reduces complaints
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More efficient processes through real-time data instead of delayed laboratory measurements
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Higher plant availability through maintenance-free sensors without consumables
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Process optimization through precise data leads to continuous improvement and better resource utilization
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Fast ROI thanks to savings on energy and operating costs
Technical specifications
Measurement accuracy | typically ±0.02 wt% |
Measurement frequency | 4 MHz |
Temperature range | -40 °C to 200 °C |
Pressure range | Up to 500 bar |
Sensor length | Up to 3000 mm |
Material & coating | Stainless steel, Hastelloy, PFA, PVDF, ETFE, ... |
Digital transmission | Up to 1,000 m (more on request) |
Interfaces | 4-20 mA, Profibus, Ethernet, Modbus, Fieldbus, ... |
Protection class | IP65 & Ex-Schutz verfügbar |
Calibration | One-time factory calibration |
Maintenance | Completely maintenance-free |
Application examples
Typical chemical process steps and our used process solutions for cleaning and etching processes as well as special etching and development processes:
SC-1 (APM)
NH4OH/H2O2
SC-2 (HPM)
HCI/H2O2
SPM (Piranha)
H2SO4/H2O2
Oxide removal (DHF)
HF
Oxide removal (BOE/BHF)
HF/NH4F
Si₃N₄ etching
H3PO4
Isotropic silicon etching
HF/HNO3
Anisotropic silicon etching (MEMS)
KOH/Si
TMAH/Si
Photoresist development
TMAH
Nitric acid / acetic acid
HNO3/CH3COOH
HF / HCl
HF/HCl
Success stories and references:
You can obtain detailed case studies and customer references from our sales team. Contact us for specific application examples from your industry.
The main advantages at a glance
Consistent quality
Real-time monitoring prevents deviations and ensures consistent product quality.
Cost savings
Reduced chemical consumption and lower operating costs through optimized processes.
Highest efficiency
Real-time data enables faster decisions and optimized processes.
Maintenance-free
Sensors are chemical-resistant and require no consumables.
Frequently asked questions
SensoTech GmbH is a leading company in the field of process measurement technology based in Barleben, near Magdeburg, Germany. We develop and produce innovative solutions for monitoring and optimizing industrial processes. Our specialization lies in the precise measurement of concentrations, densities, and other parameters in liquids – in real-time and directly during the process.
Unlike optical methods, which are influenced by color or turbidity, conductivity-based methods, which are sensitive to electrical conductivity, or density-based methods, which can be disturbed by temperature or gas bubbles, our Ultrasonic process independent of these influences.
The LiquiSonic® measuring technology also contains neither moving parts nor components that can wear out or be consumed. Therefore, after installation, the measuring system is completely maintenance-free and drift-free.
The sensors offer digital signal transmission up to 1000 m and enable continuous inline measurement without sample extraction.
Our system uses ultrasonic transit time measurement to determine the speed of sound in the liquid. This speed of sound directly correlates with the chemical concentration and enables measurement accuracies of ±0.02 wt%. The integrated temperature compensation ensures stable results even under fluctuating process conditions.
The system delivers results in real-time. At a frequency of 4 MHz 32 measurements per second are performed. Based on these measurements, you receive an up-to-date measurement value every second. This fast response time enables effective process control and early detection of deviations.
Since the speed of sound, like all other physical quantities, is influenced by temperature, all our LiquiSonic® sensors are equipped with high-precision temperature sensors. This allows the influence of temperature on the measurement to be directly compensated to be compensated. Therefore, it is not necessary to integrate additional temperature sensors.
Our sensors operate reliably in a temperature range from -40 °C to 200 °C and pressures up to 500 bar. Through various material options such as stainless steel, Hastelloy, or PFA coatings, aggressive media can also be measured. Ex protection for Zone 1 and 2 is also available.
Yes, our sensors are designed for extreme conditions. In addition to the extended temperature and pressure range, we offer customizations such as sensor lengths up to 3000 mm, special alloys for corrosive media, and various protection types, for example, optional explosion protection. Each sensor is configured individually according to your requirements configured.
Yes, by combining sound velocity measurement with additional physical quantities (e.g., conductivity), multiple components can be determined simultaneously. This also allows for monitoring of additional additives.
The system offers various digital interfaces (e.g., Profibus, Ethernet/IP, Foundation Fieldbus) as well as analog 4-20 mA outputs. The integration is seamless via standardized protocols.
The system is completely maintenance-free. There are no mechanical wear parts, seals, or optical windows that could be compromised. Regular calibration is not required - the sensors remain stable for years.
Related applications
Texturing and etching baths
In etching baths, material layers are selectively removed to create desired surface structures.
PCB cleaning
The cleaning removes organic residues, particles, and oxides, ensuring that the conductor paths can be processed reliably.
Pickling bath monitoring
Pickling baths dissolve oxides or impurities from metal surfaces and must be kept in the correct concentration range for this purpose.
Green liquor monitoring
Green liquor is a highly alkaline by-product in paper production, and its concentration must be monitored for stable subsequent processes.
Acid concentration measurement
The precise determination of concentrations in aggressive chemicals is crucial to allow reactions to proceed in a controlled and safe manner.
Scrubber
In scrubbers or neutralization plants, pollutants are removed from exhaust air or liquids, requiring precise control of the chemicals used.