Chemical delivery system with ultrasonic fluid sensors

• US 6,264,064 B1
• Filed: 10/14/1999
• Issued: 07/24/2001
• Est. Priority Date: 10/14/1999
• Status: Expired due to Term

• Current Assignee: Versum Materials US, LLC (Merck & Co., Inc.)
• Original Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Inventors: Hamidi, Jamshid Jay, Steidl, Thomas Andrew, Birtcher, Charles Michael, Martinez, Martin Castaneda
• Primary Examiner(s): Kaufman, Joseph A.
• Application Number:
  US09/418,084
• Time in Patent Office: 649 Days
• Field of Search: 222/1, 222/58, 222/61, 222/64, 222/66, 222/152, 222/189.06, 222/399, 222/481.5
• US Class Current: 222/1
• CPC Class Codes: B01J 4/02 for feeding measured , i.e. prescribed quantities of reagents
• CPC Class Codes: C23C 16/448 characterised by the method used for generating reactive gas streams, e.g. by evaporation or sublimation of precursor materials
• CPC Class Codes: Y02E 60/32 Hydrogen storage

Abstract

A chemical delivery system for delivering chemicals having at least a high purity includes at least one first reservoir for containing a fluid and at least one second reservoir for containing the fluid. The system also includes a first conduit, a first fluid sensor, and a controller. The first conduit is for transferring the fluid over time from the at least one first reservoir to the at least one second reservoir. The first conduit is metallic and has a first end in communication with the at least one first reservoir and a second end in communication with the at least one second reservoir. The fluid being transferred from the at least one first reservoir to the at least one second reservoir flows through the first conduit from the first end to the second end. The first fluid sensor is adjacent the first conduit, and the first fluid sensor is adapted to detect a presence of the fluid and to detect an absence of the fluid in the first conduit. The first fluid sensor generates at least one first signal indicative of the presence of the fluid or the absence of the fluid. The controller receives the at least one first signal. The controller is adapted to identify an empty condition in the at least one first reservoir upon receiving the at least one first signal indicative of the absence of the fluid in the first conduit or upon not receiving at least one first signal indicative of the presence of the fluid in the first conduit.

Claims

1. A chemical delivery system for delivering chemicals having at least a high purity adapted for semiconductor processing, comprising:

at least one first reservoir for containing a fluid, adapted to change out upon substantially complete utilization of said fluid;

at least one second reservoir for containing said fluid;

a first conduit for transferring said fluid over time from said at least one first reservoir to said at least one second reservoir, said first conduit being metallic and having a first end in communication with said at least one first reservoir and a second end in communication with said at least one second reservoir, wherein said fluid being transferred from said at least one first reservoir to said at least one second reservoir flows through said first conduit from said first end to said second end;

a first fluid sensor adjacent said first conduit, said first fluid sensor adapted to detect a presence of said fluid in said first conduit and to detect an absence of said fluid in said first conduit, wherein said first fluid sensor generates at least one first signal indicative of the presence of said fluid or the absence of said fluid; and

a controller for receiving said at least one first signal, said controller being adapted to identify an empty condition in said at least one first reservoir upon receiving at least one first signal indicative of the absence of said fluid in said first conduit or upon not receiving at least one first signal indicative of the presence of said fluid in said first conduit.

2. A chemical delivery system as in claim 1, further comprising means for removing at least a portion of said fluid from said at least one second reservoir.

3. A chemical delivery system as in claim 1 wherein said first fluid sensor is adjacent said first end of said first conduit.

4. A chemical delivery system as in claim 1 wherein said fluid is a liquid chemical having at least a high purity.

5. A chemical delivery system as in claim 1 wherein said first fluid sensor is an ultrasonic fluid sensor.

6. A chemical delivery system as in claim 4, further comprising:

means for pressurizing with a gas a first headspace above said liquid chemical within said at least one first reservoir; and

means for pressurizing with said gas a second headspace above said liquid chemical within said at least one second reservoir.

7. A chemical delivery system as in claim 6, wherein said gas is selected from the group consisting of helium, nitrogen, oxygen, hydrogen and argon.

8. A chemical delivery system as in claim 4, wherein said liquid chemical is selected from the group consisting of tetraethylorthosilicate, borazine, aluminum trisec-butoxide, carbon tetrachloride, trichloroethanes, chloroform, trimethylphosphite, dichloroethylenes, trimethylborate, dichloromethane, titanium n-butoxide, diethylsilane, hexafluoroacetylacetonato-copper(1)trimethylvinylsilane, isopropoxide, triethylphoshate, silicon tetrachloride, tantalum ethoxide, tetrakis(diethylamido)titanium, tetrakis(dimethylamido)titanium, bis-tertiarybutylamido silane, triethylborate, titanium tetrachloride, trimethylphosphate, trimethylorthosilicate, titanium ethoxide, tetramethyl-cyclo-tetrasiloxane, titanium n-propoxide, tris(trimethylsiloxy)boron, titanium isobutoxide, tris(trimethylsilyl)phosphate, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, tetramethylsilane and mixtures thereof.

9. A chemical delivery system as in claim 6, further comprising a vent for venting said gas from at least one of said first headspace and said second headspace.

10. A chemical delivery system as in claim 1, wherein the controller is a microcomputer.

11. A chemical delivery system for delivering liquid chemicals having at least a high purity, comprising:

at least one first reservoir for containing said liquid chemical;

at least one second reservoir for containing said liquid chemical;

means for pressurizing with a gas a first headspace above said liquid chemical within said at least one first reservoir;

means for pressurizing with said gas a second headspace above said liquid chemical within said at least one second reservoir;

a first conduit for transferring said liquid chemical over time from said at least one first reservoir to said at least one second reservoir, said first conduit being metallic and having a first end in communication with said at least one first reservoir and a second end in communication with said at least one second reservoir, wherein said liquid chemical being transferred from said at least one first reservoir to said at least one second reservoir flows through said first conduit from said first end to said second end;

a first fluid sensor adjacent said first conduit, said first fluid sensor adapted to detect a presence of said liquid chemical in said first conduit and to detect an absence of said liquid chemical in said first conduit, wherein said first fluid sensor generates at least one first signal indicative of the presence of said liquid chemical or the absence of said liquid chemical; and

a controller for receiving said at least one first signal, said controller being adapted to identify an empty condition in said at least one first reservoir upon receiving at least one first signal indicative of the absence of said liquid chemical in said first conduit or upon not receiving at least one first signal indicative of the presence of said liquid chemical in said first conduit,

a vent for venting said gas from at least one of said first headspace and said said second headspace, wherein said vent comprises;

a second conduit for exhausting at least a portion of said gas being vented; and

a second fluid sensor adapted to detect a presence of said liquid chemical in said second conduit, wherein said second fluid sensor generates at least one second signal indicative of said presence of said liquid chemical in said second conduit.

12. A chemical delivery system as in claim 11, wherein said controller receives said at least one second signal, said controller being adapted to identify an overflow of said liquid chemical from at least one of said at least one first reservoir and said at least one second reservoir upon receiving said at least one second signal.

13. A chemical delivery system as in claim 11, further comprising a source of vacuum for evacuating at least a portion of any chemicals in at least one of said first and second conduit.

14. A chemical delivery system as in claim 13, wherein said source of vacuum comprises:

a third conduit for exhausting said non-liquids; and

a third fluid sensor adapted to detect a presence of said liquid chemical in said third conduit, wherein said third fluid sensor generates at least one third signal indicative of said presence of said liquid chemical in said third conduit.

15. A chemical delivery system as in claim 14, wherein said controller receives said at least one third signal, said controller being adapted to identify a malfunction in said chemical delivery system upon receiving said at least one third signal.

16. A method of detecting an occurrence of an empty condition in a reservoir containing a liquid, said liquid having at least a high-purity and flowing over time from said reservoir through a metallic conduit in communication with said reservoir, said reservoir having a headspace pressurized by a has above said liquid, comprising the steps of:

(a) providing a fluid sensor adjacent said metallic conduit, said fluid sensor adapted to detect a presence of said liquid in said metallic conduit and to transmit at least one first signal indicative thereof, said fluid sensor also adapted to detect a presence of said gas in said metallic conduit and to transmit at least one another signal indicative thereof;

(b) detecting with said fluid sensor a presence of said liquid in said metallic conduit, said fluid sensor transmitting said at least one first signal; and

(c) identifying with said fluid sensor a subsequent absence of said liquid in said metallic conduit.

17. A method as in claim 16, wherein said fluid sensor is an ultrasonic fluid sensor.

18. A method as in claim 16, comprising the further steps of:

(d) waiting a predetermined period of time after identifying said subsequent absence of said liquid;

(e) sensing with said fluid sensor a subsequent presence of a fluid in said metallic conduit;

(f) determining with said fluid sensor whether said fluid is said liquid or said gas;

(g) repeating steps (b) through (f) if said fluid is determined to be said liquid; and

(h) transmitting at least one another signal from said fluid sensor if said fluid is determined to be said gas, said another signal indicating an occurrence of an empty condition in the reservoir.

19. A method as in claim 18, wherein said predetermined period of time is about two (2) seconds.

20. A method as in claim 16, wherein the step of (c) identifying with said fluid sensor a subsequent absence of said liquid in said metallic conduit comprises the sub-steps of:

(i) receiving said at least one first signal from said fluid sensor; and

(ii) identifying a subsequent absence of said at least one first signal from said fluid sensor.

21. A chemical delivery system for delivering a liquid chemical having at least a high purity, comprising:

at least one first reservoir for containing said liquid chemical;

at least one second reservoir for containing said liquid chemical;

a first conduit for transferring said liquid chemical over time from said at least one first reservoir to said at least one second reservoir, said first conduit being metallic and having a first end in communication with said at least one first reservoir and a second end in communication with said at least one second reservoir, wherein said liquid chemical being transferred from said at least one first reservoir to said at least one second reservoir flows through said first conduit from said first end to said second end;

a first ultrasonic fluid sensor adjacent said first conduit, said first ultrasonic fluid sensor adapted to detect a presence of said liquid chemical and to detect an absence of said liquid chemical, wherein said first ultrasonic fluid sensor generates at least one first signal indicative of the presence of said liquid chemical or the absence of said liquid chemical;

means for removing at least a portion of said liquid chemical from said at least one second reservoir;

means for pressurizing with a gas a first headspace above said liquid chemical within said at least one first reservoir;

means for pressurizing with a gas a second headspace above said liquid chemical within said at least one second reservoir;

a second conduit for venting at least a portion of said gas from at least one of said first headspace and said second headspace;

a second ultrasonic fluid sensor adapted to detect a presence of said liquid chemical in said second conduit, wherein said second ultrasonic fluid sensor generates at least one second signal indicative of said presence of said liquid chemical in said second conduit;

a third conduit for evacuating at least a portion of any non-liquids in at least one of said at least one first reservoir and said at least one second reservoir;

a third ultrasonic fluid sensor adapted to detect a presence of said liquid chemical in said third conduit, wherein said third ultrasonic fluid sensor generates at least one third signal indicative of said presence of said liquid chemical in said third conduit; and

a controller for receiving said at least one first signal, said controller being adapted to identify an empty condition in said at least one first reservoir upon receiving at least one first signal indicative of the absence of said liquid chemical in said first conduit or upon not receiving at least one first signal indicative of the presence of said liquid chemical in said first conduit, and wherein said controller receives said at least one second signal, said controller being adapted to identify an overflow of said liquid chemical from at least one of said at least one first reservoir and said at least one second reservoir upon receiving said at least one second signal, and further wherein said controller receives said at least one third signal, said controller being adapted to identify a malfunction in said chemical delivery system upon receiving said at least one third signal.

22. A chemical delivery system as in claim 21, wherein said chemical delivery system is shut down when said controller identifies any one of the following:

(a) an overflow of said liquid chemical from at least one of said at least one first reservoir and at least one second reservoir; and

(b) a malfunction in said chemical delivery system.