Characteristic test methods of the thermal mass flow controller

A thermal mass flow controller (MFC) is used to measure and control the mass flow of gases in industrial fields, for example, in the semiconductor manufacturing process. In the present study, the characteristic test methods for rangeability, linearity, reproducibility, effects of temperature and valve response time are proposed to evaluate the performance of the MFC. Three commercial MFC products are tested by gas flow standard system and a sonic nozzle to verify the effectiveness of the proposed test methods. Linearity tests show that reading errors before and after adjustment must be provided to consumers. Reproducibility tests were conducted to evaluate the short-term stability of MFCs. Temperature effect tests represent that deviation due to temperature effect of MFC body is larger than that of gas flowing. Three MFCs show different response characteristics according to direction of flow rate change in response time test by measuring the flow setpoint, flow output signal, and real flow rate.