Tunable ramp rate circuit for a mass flow controller
AssigneeApplied Materials, Inc.
InventorEric J. Linthorst
Life of this patent
Estimating the term…
Abstract
A method and apparatus for stabilizing startup gas flow through an MFC supplying reactant gases to a semiconductor system, wherein the method includes receiving a gas setpoint in a tunable activation circuit, determining a desired valve control voltage corresponding to the gas setpoint, and bypassing an MFC valve controller signal. The method further includes ramping a valve control voltage for a flow control valve of the MFC to the desired valve control voltage with the tunable activation circuit, and returning control of the MFC to an MFC valve controller circuit.
Claims5
An apparatus for stabilizing gas flow into a semiconductor processing system during startup conditions, the apparatus comprising:
- a mass flow controller having an electronic setpoint output, a gas flow input, a flow control valve, and a regulated gas flow output;
- and
- a tunable gas flow activation device in communication with the flow control valve, wherein the tunable gas flow activation device is configured to override the mass flow controller electronic set point output during a gas flow startup process and provide a selectively tunable valve control voltage to the flow control valve during the flow startup process;
- wherein the tunable gas flow activation device further comprises:
- a flow control valve voltage generating circuit;
- a previous flow data storage device in communication with the flow control valve voltage generating circuit, wherein the flow control valve voltage generating circuit is configured to access the previous flow data storage device in order to determine a flow control valve voltage;
- and
- a switching device configured to switch between outputting a mass flow controller circuit valve control voltage and a flow control valve generating circuit valve control voltage to an MFC flow control valve driver device.
A tunable gas flow control activation circuit for a mass flow controller, comprising:
- a first input for receiving a signal corresponding to a desired flow rate from a user;
- a second input for receiving a set point voltage from a mass flow controller control circuit;
- a valve control voltage generator in communication with the first input;
- a data storage device in communication with the valve control voltage generator, the data storage device having parameters corresponding to previous flow rates stored therein:
- a switching device in communication with the first and second inputs, the switching device being configured to switch between the second input and an output of the valve control voltage generator;
- and
- an output in communication with the switching device,
- wherein the tunable gas flow control activation circuit is configured to override a mass flow controller set point output during a gas flow startup process and provide a selectively tunable valve control voltage to a flow control valve of the mass flow controller during a gas flow startup process.
Dependencies are inferred from the claim text.