Thermal based mass flow control for ion implant SDS(R) applications

The economic advantage of SDS Gas Source feed materials depends largely upon maximum utilization of cylinder contents. Recent improvements in flow control technology have made it possible to utilize as much as 90% of the SDS gas cylinder contents with bottle pressures below 10 torr. This paper discusses the design and operating principles of thermal-based flow controllers and emphasizes design features for applications with inlet pressures below 10 torr. It will be shown that the thermal mass flow controller offers several advantages over alternative mass flow control and detection methods