Gas storage and dispensing system for variable conductance dispensing of gas at constant flow rate

• US 6,997,202 B2
• Filed: 12/17/2002
• Issued: 02/14/2006
• Est. Priority Date: 12/17/2002
• Status: Expired due to Fees

• Current Assignee: Advanced Technology Materials, Inc. (Entegris Incorporated)
• Original Assignee: Advanced Technology Materials, Inc. (Entegris Incorporated)
• Inventors: Olander, W. Karl
• Primary Examiner(s): Krishnamurthy, Ramesh
• Application Number:
  US10/321,757
• Publication Number:
  US 20040112435A1
• Time in Patent Office: 1,155 Days
• Field of Search: 137/2, 137/12, 137/14, 137/487.5, 137/557, 137/599.01, 137/599.06, 137/599.07, 222/1, 222/3, 222/52, 222/55, 700/282, 700/283
• US Class Current: 137/2
• CPC Class Codes: F17C 2205/0338 Pressure regulators
• CPC Class Codes: F17C 2205/0391 inside the pressure vessel
• CPC Class Codes: G05D 7/0652 the plurality of throttling means being arranged in parallel
• CPC Class Codes: Y10T 137/0324 With control of flow by a condition or characteristic of a fluid
• CPC Class Codes: Y10T 137/0379 By fluid pressure
• CPC Class Codes: Y10T 137/0396 Involving pressure control
• CPC Class Codes: Y10T 137/7758 Pilot or servo controlled
• CPC Class Codes: Y10T 137/7759 Responsive to change in rate of fluid flow
• CPC Class Codes: Y10T 137/776 Control by pressures across flow line valve
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve
• CPC Class Codes: Y10T 137/86348 Tank with internally extending flow guide, pipe or conduit
• CPC Class Codes: Y10T 137/87306 Having plural branches under common control for separate valve actuators

Abstract

A gas supply system arranged for dispensing of gas at a predetermined flow rate. The system employs a gas dispensing flow circuitry arranged for dispensing gas at selectively variable gas flow conductance conditions, to maintain the flow rate of the dispensed gas at a predetermined, e.g., constant, value in the operation of the system. The gas dispensing flow circuitry may include an array of dispensed gas flow passages, each of a differing conductance, or alternatively a variable conductance gas flow passage equipped with a variable conductance assembly for modulating the gas flow conductance of the passage, in response to sensed pressure of the gas or other system parameter. The system permits the flow rate of a dispensed gas to be maintained at a consistent desired level, despite the progressive decline in source gas pressure as the gas source vessel is depleted in use.

Claims

1. A gas supply system arranged for dispensing of gas at predetermined flow rate, comprising a gas source vessel characterized by decline in gas pressure during dispensing of gas therefrom when the gas source vessel is in a low inventory state, and gas dispensing flow circuitry coupled to said vessel, wherein the gas dispensing flow circuitry is arranged for dispensing gas at selectively variable gas flow conductance conditions, to maintain said predetermined flow rate of the dispensed gas in the operation of the system, and increasing the gas flow conductance of the gas dispensing flow circuitry to compensate for said decline in gas pressure during dispensing of gas from the gas source vessel when the gas source vessel is in a low inventory state, to maintain said predetermined flow rate, wherein the gas dispensing flow circuitry comprises a single point of entrance in fluid communication with an array of flow passages wherein all the flow passages comprise a flow control valve to open or block flow through the respective flow passage and each of the flow passages excepting one comprises a restrictive orifice having a fixed and different diameter relative to an adjacent orifice, wherein the one exception flow passage does not include a flow occlusion element and has the highest gas flow conductance of said flow passages.

2. The gas supply system of claim 1, wherein the predetermined flow rate of dispensed gas is substantially constant.

3. The gas supply system of claim 1, wherein the predetermined flow rate of dispensed gas is determined by pressure of gas in the gas source vessel.

4. The gas supply system of claim 1, wherein the gas dispensing flow circuitiy is exterior to the gas source vessel.

5. The gas supply system of claim 1, wherein the gas source vessel contains gas at superatmospheric pressure.

6. The gas supply system of claim 1, wherein the gas source vessel contains gas at subatmospheric pressure.

7. The gas supply system of claim 1, wherein the gas source vessel contains a semiconductor manufacturing gas.

8. The gas supply system of claim 7, wherein the gas dispensing flow circuitry is coupled in gas flow communication with a semiconductor manufacturing facility.

9. The gas supply system of claim 7, wherein the semiconductor manufacturing gas comprises a gas selected from the group consisting of hydride gases, halide gases and organometallic gases.

10. The gas supply system of claim 1, wherein the gas source vessel comprises a compressed gas cylinder including a valve head joined to said gas flow circuitry, wherein the valve head includes a flow control valve therein.

11. The gas supply system of claim 10, further comprising a valve actuator coupled to said flow control valve for selective operation thereof.

12. The gas supply system of claim 11, further comprising a CPU coupled to said valve actuator for actuation thereof.

13. The gas supply system of claim 1, wherein the gas dispensing flow circuitry is arranged for dispensing at least 90% of gas in said gas source vessel during said dispensing.

14. The gas supply system of claim 1, wherein the gas dispensing flow circuitry is arranged for dispensing at least 95% of gas in said gas source vessel during said dispensing.

15. The gas supply system of claim 1, wherein the gas dispensing flow circuitry is arranged for dispensing at least 98% of gas in said gas source vessel during said dispensing.

16. The gas supply system of claim 1, wherein the gas dispensing flow circuitry is coupled to a gas-consumption facility.

17. The gas supply system of claim 16, wherein the gas dispensing flow circuitry is coupled to a semiconductor manufacturing tool.

18. The gas supply system of claim 17, wherein the gas source vessel contains a semiconductor manufacturing gas.

19. The gas supply system of claim 1, wherein the gas dispensing flow circuitry comprises a regulator arranged to compensate for declining gas supply pressure during gas dispensing by adjusting the supply pressure of the dispensed gas to a predetermined value.

20. The gas supply system of claim 19, wherein the gas source vessel and gas dispensing flow circuitry are disposed in a gas cabinet including a gas panel, and the regulator is mounted on the gas panel.

21. The gas supply system of claim 1, wherein the gas dispensing flow circuitry is coupled to a downstream gas-consuming tool or locus, and a mass flow controller is provided at the downstream gas-consuming tool or locus, to control the amount and rate of gas flowed to said tool or locus.

22. A method of dispensing gas at a predetermined flow rate from a gas source vessel wherein the gas source vessel is characterized by decline in gas pressure during dispensing of gas therefrom when the gas source vessel is in a low inventory state, the method comprising:

a) dispensing under declining gas pressure said gas from the gas source vessel;

b) transporting said gas through the gas dispensing flow circuitry according to claim 1, wherein the gas flows through a first gas flow passage having a restrictive orifice comprising a smallest diameter orifice;

c) moving the gas into a next gas flow passage having a restrictive orifice comprising a diameter larger than the previous orifice;

d) repeating step c until the gas is moved into a flow passage that does not include a restrictive orifice, wherein the flow through the gas dispensing flow circuitry remains constant while the gas pressure from the gas source vessel is declining.

23. The method of claim 22, further comprising sensing pressure of gas from said gas source vessel, and responsively varying said gas flow conductance conditions.

24. The method of claim 22, further comprising utilizing said dispensed gas for semiconductor manufacturing.

25. A gas supply system arranged for dispensing of gas at predetermined flow rate, comprising a gas source vessel characterized by decline in gas pressure during dispensing of gas therefrom when the gas source vessel is in a low inventory state, and gas dispensing flow circuitry coupled to said vessel, wherein the gas dispensing flow circuitry is physisorbing medium has a sorptive affinity for the dispensed gas, arranged so that the extent of the physical adsorption of the gas on the physisorbing medium is a calibrated function of pressure of the dispensed gas.

26. A method of dispensing gas at a predetermined flow rate from a gas source vessel characterized by decline in gas pressure during dispensing of gas therefrom when the gas source vessel is in a low inventory state, comprising dispensing said gas under selectively variable gas flow conductance conditions, wherein gas flow conductance is selectively varied during dispensing to maintain said predetermined flow rate of the dispensed gas, and increasing the gas flow conductance during gas dispensing to compensate for said decline in gas pressure during dispensing of gas when the gas source vessel is in a low inventory state, to maintain said predetermined flow rate, wherein said gas flow conductance is selectively varied during dispensing by flowing the dispensed gas successively through different flow paths, wherein said different flow paths have different gas flow conductance relative to one another, wherein a highest gas flow conductance one of said different flow paths has no flow occlusion element therein and each of the others of said different flow paths has a restricted flow orifice therein.