Application
BHF Concentration Monitor, CS-137
Overview
The CS-137 is a high-precision chemical solution concentration monitor designed to meet the strict demands of semiconductor wet-etching processes. Etching processes use BHF solution to etch silicon oxide and remove particles from the wafer surface. The CS-137 continually monitors each component of the BHF solution (NH4F/HF/H2O), alerting the user each time the solution is replaced or replenished. This allows you to maintain the concentration of the BHF solution within the required component ranges, while eliminating unnecessary solution replacement.
Features
- The short 3-second measurement cycle supports concentration control for 300mm processes.
A short measurement cycle of approximately three seconds makes it possible to track concentrations close to real time. Fine-tuned concentration control makes it suitable for batch-type baths as well as single-bath cleaning devices. - The compact design of the CS-137, only two-thirds* of our previous model allow for easy integration into your wafer cleaning system.
*Compared to the CS-327 series. - Fewer lot defects in the cleaning process help improve yield
An output from the monitor is used for automated spiking control of BHF solutions, enabling a high level of repeatability of your cleaning process. As a result, lot defects decrease in the cleaning process, which helps to boost the overall yield. - Fully automated measurement simplifies control
Measurement is fully automatic, no control is required once the system has been installed and measurement has begun. Air is used for reference spectral measurement. In addition to the chemical components the water concentrations can also be measured, allowing for continuous tracking of changes in water concentration due to evaporation of the solution and adherence to the wafer. This allows fine-tuned control of silicon-oxide etching. - Comprehensive counter measures to eliminate air bubbles enable continuous measurement
A built-in bubble removal function removes air bubbles immediately before the flow cell, which allows continuous measurement of the solution as it is flowing. - The monitor uses a low-voltage (24 VDC) supply, with a load in the region of 45W makes it energy efficiency. An internal leakage sensor is also installed to detect solution leaks, so that the supply of BHF solutions can be shut off in the event of an emergency.
Manufactured by HORIBA Advanced Techno
Specifications
Model | CS-137 | ||
CS-137-2503 | CS-137-1003 | ||
Measurement sample | BHF (Hydrofluoric acid/Ammonia fluoride solution) | ||
Measurement principle | Absorption spectrometry | ||
Concentration computation principle | Temperature-compensated multivariate analysis | ||
Measurement range | NH4F: 15.0 to 25.0 % | NH4F: 0.0 to 10.0 % | |
Reproducibility | NH4F: ±0.3 % | NH4F: ±0.3 % | |
(Peak to peak)
| HF: ±0.25 % | HF: ±0.25 % | |
Chemical | Temperature | 20 to 30 °C | |
conditions | Flow rate | 20 to 60 ml/min. | |
| Pressure | 0.10 to 0.20 MPa | |
Measurement cycle | Approx. 3 seconds minimum | ||
Equipment temperature | 20 to 30 °C | ||
Operation panel | 1)Temperature level display: 2)Alarm display (Ammonia fluoride solution, Hydrofluoric acid): 3)Alarm value settings | ||
Serial input/output | RS-232C 2)Alarm value settings | ||
Parallel input | 12 to 30 V DC (photocoupler insulated) | ||
Parallel output | Maximum current when open collector output is ON: 5 mA | ||
Analog output | 4 to 20 mA (2 outputs: NH4F concentration, HF concentration) | ||
Power | 24 V DC ±10%, 2 A | ||
Dimensions | 205 (W) x 329 (D) x 269 (H) mm | ||
8.1 (W) x 13 (D) x 10.6 (H) in | |||
Mass | Approx. 11 kg | ||
Connection pipe size | For inlet and outlet: Outer diameter 6 mm (inner diameter 4 mm) | ||
Pipe connection | Nippon Pillar Super type |