Tru-Flo™ Mass Flow Verifier
The MKS Tru-Flo Mass Flow Verifier is a fully integrated diagnostic instrument that determines mass flow by measuring a pressure rate-of-rise into a known volume at a known temperature. The design integrates MKS' leading flow calibration and pressure measurement technologies by combining a Baratron? pressure sensor, shut-off valves, a small gas volume, and control electronics into a compact package. The Tru-Flo can be seamlessly incorporated into a process tool gas panel and communicates with a tool host computer via an RS 232 interface.
MKS has designed the Tru-Flo so that semiconductor equipment OEMs can easily integrate the Tru-Flo into their process gas delivery systems. Several units are currently operating in production fabs worldwide, and production orders for the product have been received.
The MKS Tru-Flo has distinct advantages over current flow verification methods. For example, the accuracy of process chamber pressure rate-of-rise tests can be degraded by chamber cleanliness and temperature fluctuations. Another common technique – comparison to a calibrated, or "golden", MFC – can also exhibit limited accuracy since golden MFCs are typically calibrated for a single surrogate gas, and measurements may not accurately represent other process gases. Both techniques typically measure only a limited flow range due to chamber volume, pressure sensor, and MFC size limitations. The Tru-Flo verification is process chamber and gas species independent, and can verify flows up to 5000 sccm.
MKS, Mass-Flo® & Advanced Materials Delivery Products, 651 Lowell Street, Methuen, MA 01844. Tel: 978-682-4567; Fax: 978-691-1170.