System and method for detecting flow in a mass flow controller

• US 7,255,128 B2
• Filed: 07/06/2006
• Issued: 08/14/2007
• Est. Priority Date: 08/30/2001
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Rueger, Neal R., Sandhu, Gurtej Singh, Sharan, Sujit, Mardian, Allen P.
• Primary Examiner(s): NOLAND, THOMAS
• Application Number:
  US11/456,055
• Publication Number:
  US 20060236513A1
• Time in Patent Office: 404 Days
• Field of Search: 32420715-20716, 324/207.22, 738/659, 137/554, 29/250.1, 700/282, 118/728
• US Class Current: 137/554
• CPC Class Codes: G01F 1/40 Details of construction of the flow constriction devices
• CPC Class Codes: G01F 1/42 Orifices or nozzles
• CPC Class Codes: G01P 13/0006 of fluids or of granulous or powder-like substances
• CPC Class Codes: G01P 13/0013 by using a solid body which is shifted by the action of the fluid
• CPC Class Codes: G01P 13/0033 with electrical coupling to the indicating device
• CPC Class Codes: G05D 7/0635 by action on throttling means G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: Y10T 137/0396 Involving pressure control
• CPC Class Codes: Y10T 137/7722 Line condition change responsive valves
• CPC Class Codes: Y10T 137/775 With manual modifier
• CPC Class Codes: Y10T 137/8242 Electrical

Abstract

Systems and methods are provided for detecting flow in a mass flow controller (MFC). The position of a gate in the MFC is sensed or otherwise determined to monitor flow through the MFC and to immediately or nearly immediately detect a flow failure. In one embodiment of the present invention, a novel MFC is provided. The MFC includes an orifice, a mass flow control gate, an actuator and a gate position sensor. The actuator moves the control gate to control flow through the orifice. The gate position sensor determines the gate position and/or gate movement to monitor flow and immediately or nearly immediately detect a flow failure. According to one embodiment of the present invention, the gate position sensor includes a transmitter for transmitting a signal and a receiver for receiving the signal such that the receiver provides an indication of the position of the gate based on the signal received. Other embodiments of the gate position sensor are described herein, as well as systems and methods that incorporate the novel MFC within a semiconductor manufacturing process.

Claims

1. A gate position sensor, comprising:

an orifice and a gate adapted to adjust flow through the orifice;

a magnet to generate a magnetic flux; and

an induction coil and an electromagnetic pulse detector adapted to cooperate to detect a magnetically induced signal in the induction coil when gate movement provides relative movement between the magnet and the coil.

2. The sensor of claim 1, wherein the orifice and the gate are an orifice and a gate from an ultrasonic mass flow controller adapted to control gas flow from a semiconductor gas source to a semiconductor processing chamber.

3. The system of claim 1, wherein the gate is adapted to oscillate between an open and closed position with respect to the orifice.

4. A gate position sensor, comprising:

a transmitter for transmitting a signal in a flow controller, wherein a position of a gate in the flow controller affects the signal; and

a receiver for receiving the signal, wherein the receiver is adapted to provide a signal output for the sensor to indicate a gate position within the flow controller based on the signal received,

wherein the transmitter is a magnet, the signal is magnetic flux from the magnet, and the receiver is a combination of a cooperating induction coil and an electromagnetic pulse detector for detecting a magnetically induced signal in the induction coil, and wherein gate movement induces the signal by providing relative movement between the magnet and the coil.

5. The sensor of claim 4, wherein the transmitter includes a transmitter for transmitting a signal in a mass flow controller.

6. The sensor of claim 4, wherein the transmitter includes a transmitter for transmitting a signal in an ultrasonic mass flow controller.

7. A gate position sensor for a flow controller having an orifice and a gate for closing the orifice, comprising:

a magnet;

a cooperating induction coil operably positioned with respect to the magnet, wherein the magnet and the induction coil are operably positioned with respect to the gate of the flow controller; and

an electromagnetic pulse detector such that movement of the gate generates a magnetically induced signal in the induction coil detectable by the detector.

8. The electromagnetic gate position sensor of claim 7, wherein the magnet includes a permanent magnet.

9. The electromagnetic gate position sensor of claim 7, wherein the magnet includes an electrically activated magnetic coil.

10. The sensor of claim 7, wherein the sensor is adapted to sense gate movement for an ultrasonic mass flow controller.

11. The sensor of claim 7, wherein the sensor is adapted for use in monitoring a frequency of gate oscillations.

12. A system, comprising:

an ultrasonic mass flow controller with an orifice and a gate adapted to close the orifice; and

a sensor, including a magnet to generate a magnetic flux, and an induction coil and an electromagnetic pulse detector adapted to cooperate to detect a magnetically induced signal in the induction coil when gate movement provides relative movement between the magnet and the coil.

13. The system of claim 12, further comprising:

a semiconductor gas source;

a semiconductor processing chamber; and

a gas flow line connecting the gas source to the processing chamber, the ultrasonic mass flow controller being adapted to control gas flow through the line from the gas source to the processing chamber.

14. The system of claim 12, further comprising a processor connected to the ultrasonic mass flow controller and the electromagnetic pulse detector.

15. The system of claim 12, wherein the sensor is adapted to sense gate movement.

16. The system of claim 12, wherein the sensor is adapted for use in monitoring a frequency of gate oscillations.

17. The system of claim 12, wherein the magnet includes a permanent magnet.

18. The system of claim 12, wherein the magnet includes an electrically activated magnetic coil.

19. A system, comprising:

an inflow line;

a flow controller positioned in the inflow line for controlling flow, the flow controller including a gate and an actuator for moving the gate to control flow;

a gate position sensor for monitoring whether the gate is in an opened position or a closed position, the sensor including means for transmitting a signal in the flow controller such that a position of the gate in the flow controller affects the signal, and means for receiving the signal and providing a signal output for the sensor to indicate a gate position within the flow controller based on the signal received; and

a processor for controlling the position of the gate and for interfacing with the sensor,

wherein the sensor includes a magnet, a cooperating induction coil, and an electromagnetic pulse detector, wherein the magnet and the induction coil are operably positioned with respect to the gate, and wherein movement of the gate generates a magnetically induced signal in the induction coil detectable by the electromagnetic pulse detector.

20. The system of claim 19, further comprising:

a semiconductor gas source; and

a semiconductor processing chamber, wherein the ultrasonic mass flow controller is adapted to control gas flow through the inflow line from the gas source to the processing chamber.

21. The system of claim 19, wherein the sensor is adapted to sense gate movement.

22. The system of claim 19, wherein the sensor is adapted for use in monitoring a frequency of gate oscillations.

23. The system of claim 19, wherein the magnet includes a permanent magnet.

24. The system of claim 19, wherein the magnet includes an electrically activated magnetic coil.

25. A semiconductor manufacturing system, comprising:

an ultrasonic semiconductor gas line;

a processing chamber coupled to the gas line;

a flow controller positioned in the gas line, wherein the flow controller further includes;

an orifice;

a gate for controlling gas flow through the orifice and into the processing chamber;

an actuator for oscillating the gate between an opened position and a closed position to control gas flow;

a transmitter for transmitting a signal in the flow controller; and

a receiver for receiving the signal such that the receiver provides an indication of whether the gate is in an opened position or a closed position based on the signal received; and

a processor for interfacing with the actuator, the transmitter and the receiver to control the position of the gate,

wherein the transmitter is a magnet, the signal is magnetic flux from the magnet, and the receiver is a combination of a cooperating induction coil and an electromagnetic pulse detector for detecting a magnetically induced signal in the induction coil, wherein the magnet and the cooperating induction coil are operably positioned with respect to the gate such that a movement of the gate induces the magnetically induced signal in the induction coil by providing relative movement between the magnet and the coil.

26. The system of claim 25, wherein the magnet includes a permanent magnet.

27. The system of claim 25, wherein the magnet includes an electrically activated magnetic coil.