Key in advanced manufacturing processes such as the creation of silicon chips, mass flow controllers (MFCs) monitor and adjust gas flow into production chambers. These devices need to be precise, accurate, and quick to respond to changes in gas flow rate.
Additionally, if an MFC fails, production must be stopped. Without a way to identify which MFC out of dozens failed, clients of MKS Instruments would replace all MFCs on a line to avoid even costlier downtime. Seeking an improved MFC that would address this and other challenges, MKS reached out to Cooper Perkins, and the resulting partnership produced an innovative product with three new features.
Typically, dozens of MFCs are implemented on manifolds feeding into a controlled manufacturing chamber, ensuring that the flow of gas through each line meets required parameters. If even one MFC fails, conditions in the chamber will change and cause production to be halted. Previously, there was no way to identify which controller failed, so all would be replaced to avoid costly production downtime.
We designed the piMFC to have an individual modem and connect through ethernet to a user interface. This meant that each controller included full diagnostic capabilities, allowing malfunctions to be sensed before chamber conditions were affected and operators to instantly isolate the problem to a single controller.
As production processes require precise quantities of gas to be provided in a steady flow, MFCs measure gas at the molecular level and ensure that the flow rate meets parameters. Any pressure disturbances up or downstream would deceive existing MFCs, leading to an uncontrolled response and delivering an inaccurate amount of gas to the process.
In order to achieve the accuracy and precision required, we needed to ensure that changes in the surrounding environment didn’t affect the readings. We solved this by mechanically suspending the sensors to thermally isolate them and calibrating readings based on the sensed ambient temperature.
To prevent pressure disturbances from impacting gas flow, we developed a finely tuned control system that would take sensor readings, calculate variation in flow rate, and trigger a custom-designed, proportional valve to adjust accordingly to maintain a constant flow.
On-Chamber
A 1.5kW DC source RF power amplifier used to control the remote delivery of plasma to semiconductor process chambers. The device utilized unique technology based on electronic impedance matching network within a thermally controlled chassis to actively address heat dissipation.
By including not only extreme precision and pressure disturbance insensitivity, but also individual diagnostic capability through ethernet connection, the piMFC transformed expectations for what a mass flow controller could be.
