Method and apparatus for making a vapor of precise concentration by sublimation
AssigneeCeeVee Tech, LLC
InventorEgbert G. Woelk
Life of this patent
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Abstract
Techniques for controlling a solid precursor vapor source are provided. An example method of controlling a solid precursor vapor source includes providing a carrier gas to a sublimation vessel containing a solid precursor material, wherein the carrier gas is heated with a carrier gas temperature control device prior to entering the sublimation vessel, measuring a temperature of a vapor exiting the sublimation vessel, and controlling a temperature of the carrier gas with the carrier gas temperature control device based at least in part on the temperature of the vapor exiting the sublimation vessel.
Claims10
An apparatus, comprising:
- a sublimation vessel containing a solid precursor material;
- a carrier gas heater configured to control a temperature of a carrier gas entering the sublimation vessel;
- a first temperature sensor configured to measure a temperature of the carrier gas entering the sublimation vessel;
- a second temperature sensor configured to measure a temperature of a vapor exiting the sublimation vessel;
- and
- a controller communicatively coupled to the carrier gas heater, the first temperature sensor, and the second temperature sensor, and configured to:
- compute a delta temperature value based on a vapor pressure of the solid precursor material at a sublimation temperature, a sublimation vessel pressure value, a heat of sublimation value for the solid precursor material, and a specific heat of the carrier gas at a constant pressure;
- and
- control the temperature of the carrier gas with the carrier gas heater based on the temperature of the vapor exiting the sublimation vessel and the delta temperature value, wherein the carrier gas temperature is controlled such that the temperature of the carrier gas entering the sublimation vessel is equal to the temperature of the vapor exiting the sublimation vessel plus the delta temperature value.
An apparatus for controlling a solid precursor vapor source, comprising:
- means for providing a carrier gas to a sublimation vessel containing a solid precursor material, wherein a temperature of the carrier gas is controlled with a carrier gas temperature control device prior to entering the sublimation vessel;
- means for measuring the temperature of the carrier gas entering the sublimation vessel;
- means for measuring a temperature of a vapor exiting the sublimation vessel;
- means for computing a delta temperature value based on a vapor pressure of the solid precursor material at a sublimation temperature, a sublimation vessel pressure value, a heat of sublimation value for the solid precursor material, and a specific heat of the carrier gas at a constant pressure;
- and
- means for controlling the temperature of the carrier gas with the carrier gas temperature control device based on the temperature of the vapor exiting the sublimation vessel and the delta temperature value, wherein the carrier gas temperature is controlled such that the temperature of the carrier gas entering the sublimation vessel is equal to the temperature of the vapor exiting the sublimation vessel plus the delta temperature value.
Dependencies are inferred from the claim text.