Patents

Valve Assembly And System Used to Control Flow Rate of A Fluid

Patent Application US 2025/0130600 A1 Valve Assembly and System Used to Control Flow Rate of a Fluid Filed: October 20, 2023 | Published: April 24, 2025

The Problem

Mass flow controllers (MFCs) are the devices that precisely meter process gases into semiconductor wafer fabrication chambers. Accuracy matters enormously, and a single  miscalibrated MFC can ruin an entire wafer batch. The accuracy range of an MFC is fundamentally limited by the pressure sensor inside it, and conventional pressure sensors are only reliable within a narrow linear operating range. This forces fabs to deploy multiple MFCs to cover different flow ranges which adds cost, complexity, and failure points.

The root cause: standard pressure transducers use diaphragms designed to stay within their linear deflection range. Once pressure exceeds that range, the sensor's output becomes non-linear and unpredictable, so engineers simply don't use them there, even though the hardware could physically survive it.

The Invention

This patent covers an MFC architecture that deliberately exploits the non-linear response region of a pressure transducer diaphragm rather than avoiding it. By characterizing and mathematically modeling both the linear and non-linear behavior of a thin diaphragm, the system can accurately measure pressures across a range far exceeding what conventional designs allow, up to 60 PSI with a sensor rated linearly to only 5 PSI.

The result is an MFC with a 500:1 operating range, compared to the typical 20:1 range of conventional devices. A single unit can replace two conventional MFCs across the same flow range, while maintaining 1% accuracy and long-term stability.

My Contribution

I am a named co-inventor on this application, contributing to the mechanical design of the valve and transducer assembly, the experimental characterization of sensor behavior across linear and non-linear operating regimes, and the development of test methodology used to validate the performance claims in the filing.