Method and apparatus for monitoring solid precursor delivery
First Claim
1. An apparatus for monitoring delivery of a solid precursor from a vessel to a process chamber via a process gas, comprising:
- a gas analyzing means to generate a first signal indicative of a density of the precursor in the process gas; and
a controller to receive the first signal and a second signal indicative of a volume flow rate of the process gas or a carrier gas flowing into the vessel to produce the process gas, wherein the controller is configured to calculate an amount of precursor remaining in the vessel based, at least in part, on the first and second signals.
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Abstract
A method and apparatus for monitoring the delivery of a solid precursor from a vessel to a process chamber via a process gas produced by flowing a carrier gas into the vessel is provided. The precursor typically changes state from a solid to a gas (vapor) through a sublimation process within the chamber. The apparatus comprises a gas analyzer to generate a first signal indicative of a density of the precursor in the process gas and a controller. The controller receives the first signal and a second signal indicative of a volume flow rate of the process gas or the carrier gas and calculates a mass flow rate and/or a total amount consumed of the precursor based on the first and second signals. The controller may calculate an amount precursor remaining in the vessel based on the total amount consumed and an initial amount. The amount of precursor remaining in the vessel may be used by an operator to efficiently schedule replacement or replenishment of the precursor in an effort to minimize material waste and processing down time.
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Citations
35 Claims
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1. An apparatus for monitoring delivery of a solid precursor from a vessel to a process chamber via a process gas, comprising:
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a gas analyzing means to generate a first signal indicative of a density of the precursor in the process gas; and
a controller to receive the first signal and a second signal indicative of a volume flow rate of the process gas or a carrier gas flowing into the vessel to produce the process gas, wherein the controller is configured to calculate an amount of precursor remaining in the vessel based, at least in part, on the first and second signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
calculate a mass flow rate of the precursor based on the first and second signals; and
calculate an amount of precursor remaining in the vessel based on the mass flow rate and an initial amount.
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4. The apparatus of claim 3, wherein the controller is also configured to predict an amount of processing time remaining before the precursor is depleted.
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5. The apparatus of claim 1, wherein the precursor comprises a precursor to deposit a layer of conductive material.
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6. The apparatus of claim 1, wherein the precursor comprises a metalorganic material.
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7. The apparatus of claim 6, wherein the precursor comprises tungsten carbonyl.
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8. The apparatus of claim 1, wherein the controller is configured to communicate the mass flow rate of the precursor to an external device.
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9. The apparatus of claim 1, wherein the gas analyzing means comprises a gas analyzer utilizing ultrasonic transducers to generate the first signal.
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10. The apparatus of claim 1, wherein the controller is configured to communicate, to an external device, at least one of:
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the mass flow rate of the precursor; and
the amount of precursor remaining in the vessel.
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11. An apparatus for monitoring delivery of a solid precursor from a vessel to a process chamber via a process gas, comprising:
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a gas analyzer having a Fourier transform infrared (FTIR) spectrometer to generate a first signal indicative of a density of the precursor in the process gas, wherein the FTIR spectrometer is optimized for a limited range of wavenumbers dependent on a material of the precursor;
a flow meter to generate a second signal indicative of a volume flow rate of the process gas; and
a controller configured to calculate a mass flow rate of the precursor based on the first and second signals. - View Dependent Claims (12, 13, 14)
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15. A method for monitoring delivery of a solid precursor from a vessel to a process chamber, comprising:
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measuring a density of the precursor in a process gas flowing from the vessel to the process chamber, wherein the process gas is produced by flowing a carrier gas into the vessel;
measuring a volume flow rate of the process gas or the carrier gas; and
calculating an amount of the precursor remaining in the vessel based on the measured density of the precursor in the process gas and the measured volume flow rate of the process gas or the carrier gas. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. A method for monitoring delivery of a solid precursor from a vessel to a process chamber, comprising:
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generating a Fourier transform infrared (FTIR) spectrum of a process gas flowing from the vessel to the chamber, wherein the process gas is produced by flowing a carrier gas into the vessel and the FTIR spectrum is generated for a limited range of wavenumbers selected based on the precursor;
calculating a density of the precursor in the process gas based on the FTIR spectrum;
measuring a volume flow rate of the process gas or the carrier gas; and
calculating a mass flow rate of the precursor based on the measured density of the precursor in the process gas and the measured volume flow rate of the process gas or the carrier gas.
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24. A system comprising:
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a process chamber;
a gas delivery system to deliver a solid precursor from a vessel to the process chamber via a process gas produced by flowing a carrier gas into the vessel; and
a precursor monitoring apparatus disposed between the process chamber and the gas delivery system, the precursor monitoring apparatus having a gas analyzer to generate a first signal indicative of a density of the precursor in the process gas and an integral controller to receive the first signal and a second signal indicative of a volume flow rate of the process gas or the carrier gas, wherein the integral controller is configured to calculate a mass flow rate of the precursor based on the first and second signals and an amount of precursor remaining in the vessel based on the mass flow rate of the precursor and an initial amount. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33)
a) the amount of precursor remaining in the vessel; and
b) the mass flow rate of the precursor.
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30. The system of claim 29, wherein the system controller is configured to regulate delivery of the precursor by the gas delivery system based on the information received from the integral controller.
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31. The system of claim 30, wherein the system controller regulates delivery of the precursor by adjusting a temperature of the precursor within the vessel.
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32. The system of claim 31, wherein the system controller regulates delivery of the precursor by adjusting a volume flow rate of the carrier gas.
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33. The system of claim 24, wherein the integral controller is further configured to calculate a total amount of precursor delivered to a wafer in the process chamber during one or more precursor delivery cycles.
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34. An apparatus for monitoring delivery of a solid precursor from a vessel to a process chamber via a process gas, comprising:
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a gas analyzer utilizing ultrasonic transducers to generate a first signal indicative of a density of the precursor in the process gas;
a flow meter to generate a second signal indicative of a volume flow rate of the process gas; and
a controller configured to calculate a mass flow rate of the precursor based on the first and second signals and to calculate an amount of precursor remaining in the vessel based on an initial amount. - View Dependent Claims (35)
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Specification