WhitePaper: Model V8 Sapphire Diaphragm Gauge

The Model V8 is a diaphragm vacuum gauge developed by Azbil to address the evolving needs of semiconductor process equipment, specifically deposition shift problems and the demand for high-temperature and high-speed capabilities.

Product lineup

• Integrated Model (V8C): Combines sensor and measurement circuit in a single enclosure.
• Separated Model (V8S): Sensor and measurement circuit housed in separate enclosures.

Key features

1. Sapphire material properties

• Heat resistance: Sapphire (Al₂O₃) operates up to 1950°C under atmospheric conditions.
• Corrosion resistance: Excellent resistance to acids, alkalis, and corrosive gases (e.g., fluorine, chlorine).

2. Sensor design

• Diaphragm and pedestal: Both made of sapphire, directly bonded for corrosion and heat resistance.
• Electrodes: Two pairs of metal electrodes form pressure-sensitive capacitance (C_X) and reference capacitance (C_R), enabling temperature compensation.

3. Deposition shift solutions

• Fine uneven structure: 6 µm grooves on the diaphragm reduce deposition-induced shifts to less than one-tenth of previous models in SiO₂-CVD processes.
• Flat diaphragm: Moment-balanced structure minimises stress-induced displacement, effective for ALD processes.

4. Temperature and speed performance

• Separated model (V8S): Supports 10–250°C with proprietary temperature correction.
• Integrated model (V8C): Variable self-heating temperature (45–200°C) for process flexibility.
• Response speed: Achieves 1 ms or less (63% response rate) and a 0.27 ms pressure update cycle.

5. Sensor package

• Diffusion-bonded metal ring and chemical getter pump maintain vacuum integrity.
• Flat baffle plate protects the sensor from solid matter.

Conclusion

The Model V8 delivers improved deposition resistance, high-temperature operation, and rapid response, addressing critical challenges in semiconductor manufacturing.