Enables "Wafer-to-Wafer" "Chamber-to-Chamber" & "Tool-to-Tool" Matching
The HA-MFV, High Accuracy Mass Flow Verifier is designed for use on process tools to verify mass flow control flow rates in-situ. Available with EtherCAT® or DeviceNet™ communications and measurement accuracy of 1.0% of reading, the HA-MFV can verify MFC flow with the actual process gas significantly better than older rate-of-rise devices or process chamber rate-of rise methods.
The insensitivity of the HA-MFV to external volume is realized through the use on sonic nozzle technology. The sonic nozzle creates a pressure drop and sonic flow conditions. In sonic flow, variations in pressure downstream of the nozzle have no effect on upstream conditions. Thus, the sonic nozzle effectively decouples the measurement in the HA-MFV from the upstream volume.
The HA-MFV is able to provide significantly better measurement accuracy and is insensitive to external volume (volume from MFC to the HA-MFV) conditions and variation. This insensitivity of the HA-MFV to external volume also results in more precise matching of measurements between HA-MFVs on multiple tools for the same process. This assures the user of precise tool-to-tool process matching.