HITACHI SAM PS100 series pressure based PI mass flow controller

HITACHI SAM PS100 series pressure based PI mass flow controller

Overview

In semiconductor manufacturing processes, mass flow controllers are one of the most critical components that determine process accuracy and repeatability. The Hitachi SAM PS100 series quality flow controller adopts an innovative pressure based flow measurement architecture, providing a new solution for this demanding application. This series of products is designed with the core concept of "speed, accuracy, and maintainability", and meets the strict requirements of modern semiconductor processes for flow control through a non heating flow measurement architecture, improved pressure insensitivity characteristics, and excellent response speed.

The PS100 series is specially optimized for thermal degradation gases and corrosive gases. Its unique structure enables stable flow control during pressure fluctuations at the inlet and outlet, providing reliable support for key processes such as atomic layer deposition, etching, and thin film deposition.

Core Technology and Design Philosophy

2.1 Pressure based flow measurement architecture

The PS100 series adopts an innovative non heating flow measurement architecture. Compared to traditional thermal MFCs, this design brings significant advantages:

Reduce reaction by-products: The non heating design significantly reduces the reaction attachments generated on the inner surface of MFC due to thermal degradation gases, maintaining the cleanliness of the flow channel.

Enhance corrosion resistance: For corrosive gases such as CL ₂ and BCl ∝, corrosion will accelerate rapidly in the presence of trace amounts of moisture and under high temperature conditions. The unheated design of PS100 effectively suppresses this electrochemical corrosion and extends the lifespan of the equipment.

Long term stability: avoids sensor characteristic drift and channel surface state changes caused by heating, achieving long-term stable flow measurement and control.

2.2 Improved pressure insensitive function

In semiconductor processes, fluctuations in gas source pressure or changes in reaction chamber pressure are common disturbance factors. The PS100 series achieves excellent pressure insensitivity through its unique mechanical structure design

Upstream pressure fluctuation suppression: The built-in mechanical pressure regulator can effectively respond to pressure fluctuations at the intake end and maintain stable pressure difference before and after the internal measurement throttle element of MFC.

Downstream pressure fluctuation suppression: A control valve with high response speed can compensate for the impact of pressure changes at the exhaust end on flow rate in real time.

Double protection: This upstream and downstream coordinated regulation structure enables PS100 to achieve highly stable flow control even under severe pressure fluctuations.

2.3 Excellent repeatability and wide flow range

Excellent repeatability: Thanks to the stable pressure conditions established in the throttling element, PS100 can still achieve excellent flow repeatability even when there are pressure fluctuations upstream and downstream of MFC, ensuring highly consistent process results for each wafer.

Wide flow control range: Under the condition of outlet pressure below 60kPa (absolute pressure), PS100 can achieve wide range flow control from 0.5% to 100% of full range. This means that in gas systems, one PS100 can replace multiple MFCs with different ranges, improving the flexibility of equipment configuration.

11 BIN multi gas/multi range compatibility: The PS100 series is compatible with a wide flow range from 5 SCCM to 5 SLM with a single MFC, supported by 11 BINs (basic calibration database), and is compatible with multiple gases. This enables the conversion of gas types or flow rates on-site without the need for hardware replacement, greatly enhancing the flexibility of process development and equipment maintenance.

Performance highlights and technical specifications

3.1 High precision and fast response

High precision: Within the range of 10% to 100% of the set point, the accuracy of PS100 is as high as ± 1% (N ₂) of the set point, and within the range of 0.5% to 10%, it is ± 0.1% F.S. This high precision is due to the stable pressure sensing condition design.

Fast response: By applying improved control algorithms, PS100 achieved a typical fast rise and fall response characteristic of 0.6 seconds. After the set value is reset to zero, the airflow can quickly stop, which is crucial for applications that require rapid process switching.

3.2 Excellent valve performance

High shut-off performance: After the flow setting value is reset to zero, gas residue downstream of the MFC valve to the process pneumatic valve is a potential issue. The PS100 series achieves a high valve shut-off performance of 0.1% F.S. (when each BIN is set to full range), effectively reducing the impact of residual gases on the process.

Long life diaphragm valve: For processes such as atomic layer deposition that require frequent valve opening and closing, PS100 adopts optimized driving circuits, piezoelectric ceramic components, and cobalt nickel alloy diaphragms, achieving a 10 million cycle opening and closing life, ensuring long-term reliability.