Supercritical fluid delivery and recovery system for semiconductor wafer processing

• US 6,612,317 B2
• Filed: 04/18/2001
• Issued: 09/02/2003
• Est. Priority Date: 04/18/2000
• Status: Expired due to Fees

• Current Assignee: SC Fluids, Inc.
• Original Assignee: SC Fluids, Inc.
• Inventors: Jafri, Ijaz H., Chandra, Mohan, Mount, David J., Moritz, Heiko D., Costantini, Michael A., Heathwaite, Rick M.
• Primary Examiner(s): Coe, Philip R.
• Application Number:
  US09/837,507
• Publication Number:
  US 20010050096A1
• Time in Patent Office: 867 Days
• Field of Search: 134/105, 134/107, 134/108, 134/57.R, 134/58.R, 134/56.R, 68/18.R, 68/18.C
• US Class Current: 134/58.00R
• CPC Class Codes: B01J 3/008 Processes carried out under supercritical conditions
• CPC Class Codes: B08B 7/0021 by liquid gases or supercritical fluids
• CPC Class Codes: H01L 21/67034 for drying
• CPC Class Codes: Y02P 20/54 using solvents, e.g. supercritical solvents or ionic liquids

Abstract

A continuous flow, steady state fluid delivery and recovery system for a process chamber and processes requiring supercritical fluid and desired additives including co-solvents, for conducting repetitive batch processing operations in an automated environment, for such processes as supercritical carbon dioxide cleaning and processing of semiconductor wafers. The system provides for steady-state operation of fluid flow and byproducts recovery while the process chamber is brought rapidly and repeatedly on and off line as in batch operations and for various process steps.

Claims

1. A continuous flow fluid delivery and recovery system for supporting the operation of a supercritical phase process in a batch-operated process chamber, comprising

(a) a pressurized fluid delivery system including a process fluid supply system and pump for supplying a process fluid at a pre-process pressure, and a heater for heating and maintaining said process fluid under said pre-process pressure at a pre-process temperature, said pre-process pressure and said pre-process temperature in combination placing said process fluid in supercritical phase,

(b) a process byproducts recovery system for collecting byproducts of said process, said recovery system including means for recovering said process fluid from said byproducts and returning said process fluid to said process fluid supply system,

(c) means for controlling temperature within said process chamber,

(d) a process chamber inflow valve for connecting said fluid delivery system to said process chamber for fluid flow,

(e) a process chamber outflow valve for connecting said process chamber to said recovery system for fluid flow,

(f) a process chamber bypass valve for connecting said fluid delivery system to said recovery system so as to bypass said process chamber, and

(g) a computer control system controlling said pump, said heater, said means for controlling temperature within said process chamber, and said valves, said valves being operable so as to provide continuous flow of said process fluid in said delivery system.

2. A continuous flow fluid delivery and recovery system according to claim 1, said fluid delivery system further comprising a ballast tank and ballast tank heater for accumulating said process fluid for rapid discharge into said process chamber.

3. A continuous flow fluid delivery and recovery system according to claim 2, further comprising a ballast bypass control valve for permitting fluid flow to bypass said ballast tank, said ballast bypass control valve being controlled by said computer control system.

4. A continuous flow fluid delivery and recovery system according to claim 1, said recovery system further comprising a recovery volume connecting to said process chamber for receiving a rapid discharge of said process byproducts from said process chamber, and recovery volume control valves for selecting and de-selecting said recovery volume from said recovery system, said recovery volume control valves being controlled by said computer control system.

5. A continuous flow fluid delivery and recovery system according to claim 4, said byproducts recovery system further comprising at least one separator for separating process gas from liquid.

6. A continuous flow fluid delivery and recovery system according to claim 1, said means for controlling temperature with said process chamber comprising a liquid heating and cooling subsystem, inflow and outflow lines connecting said subsystem to at least one heat exchanger within said process chamber, and control valves for controlling flow in said heat exchanger, said subsystem and said control valves being controlled by said computer control system.

7. A continuous flow fluid delivery and recovery system according to claim 1, said process fluid being carbon dioxide.

8. A continuous flow fluid delivery and recovery system according to claim 1, in combination with at least one batch operated process chamber, said supercritical phase process being the cleaning and processing of semiconductor wafers, the opening, loading and unloading, and closing of said process chamber being controlled by said computer control system.

9. A continuous flow fluid delivery and recovery system according to claim 1, said fluid delivery system further comprising means for condensing a process fluid gas to a liquid, at least one gas supply line connecting to said pressure chamber and a liquid supply line connecting to said chamber, said lines having respective chamber inflow control valves, said respective chamber inflow control valves being controlled by said computer control system.

10. A continuous flow fluid delivery and recovery system for supporting the operation of a supercritical phase process in a batch-operated process chamber, comprising

(a) a pressurized fluid delivery system including a process fluid supply system and pump for supplying a process fluid at a pre-process pressure, a process additive supply system and pump for supplying a process fluid additive to said process fluid, means for mixing said process fluid and said process fluid additive into a fluid mixture, and a heater for heating and maintaining said fluid mixture under said pre-process pressure at a pre-process temperature, said pre-process pressure and said pre-process temperature in combination placing said fluid mixture in supercritical phase,

(b) a process byproducts recovery system for collecting byproducts of said process, said recovery system including means for recovering said process fluid from said byproducts and returning said process fluid to said process fluid supply system,

(c) means for controlling temperature within said process chamber,

(d) an inflow valve for connecting said fluid delivery system to said process chamber for fluid flow,

(e) an outflow valve for connecting said process chamber to said recovery system for fluid flow,

(f) a bypass valve for connecting said fluid delivery system to said recovery system so as to bypass said process chamber, and

(g) a computer control system controlling said pump, said heater, said means for controlling temperature within said process chamber, and said valves, said valves being operable so as to provide continuous flow of said process fluid from said delivery system to said recovery system.

11. A continuous flow fluid delivery and recovery system according to claim 10, said fluid delivery system further comprising a ballast tank and ballast tank heater for accumulating said fluid mixture for rapid discharge into said process chamber.

12. A continuous flow fluid delivery and recovery system according to claim 11, further comprising a ballast bypass control valve for permitting fluid flow to bypass said ballast tank, said ballast bypass control valve being controlled by said computer control system.

13. A continuous flow fluid delivery and recovery system according to claim 10, said recovery system further comprising a recovery volume connecting to said process chamber for receiving a rapid discharge of said process byproducts from said process chamber, and recovery volume control valves for selecting and de-selecting said recovery volume from said recovery system, said recovery volume control valves being controlled by said computer control system.

14. A continuous flow fluid delivery and recovery system according to claim 13, said byproducts recovery system further comprising at least two separators for separating byproducts gas from liquid and control valves associated therewith, said control valves being operable to connect a first said separator to said process chamber and a second said separator to said chamber bypass valve so as to permit concurrent discharge of said chamber and bypass circulation from said fluid delivery system, said valves being controlled by said computer control system.

15. A continuous flow fluid delivery and recovery system according to claim 10, said recovery system further comprising means for recovering said process additives from said byproducts and returning said additives to said process additive supply system.

16. A continuous flow fluid delivery and recovery system according to claim 10, said means for controlling temperature with said process chamber comprising a liquid heating and cooling subsystem, inflow and outflow lines connecting said subsystem to at least one heat exchanger within said process chamber, and control valves for controlling flow in said heat exchanger, said subsystem and said control valves being controlled by said computer control system.

17. A continuous flow fluid delivery and recovery system according to claim 10, said process fluid being carbon dioxide.

18. A continuous flow fluid delivery and recovery system according to claim 10, in combination with at least one batch operated process chamber, said supercritical phase process being the cleaning and processing of semiconductor wafers, the opening, loading and unloading, and closing of said process chamber being controlled by said computer control system.

19. A continuous flow fluid delivery and recovery system according to claim 10, said fluid delivery system further comprising means for condensing said process fluid gas to liquid, a process fluid gas supply line connecting to said process chamber, at least one fluid mixture supply line connecting to said process chamber and a liquid supply line connecting to said chamber, all said lines having respective chamber inflow control valves, said respective chamber inflow control valves being controlled by said computer control system.

20. A continuous flow fluid delivery and recovery system in combination with at least one batch operated process chamber for the operation of a supercritical phase process, comprising

(a) a pressurized fluid delivery system including a process fluid supply system and pump for supplying a process fluid at a pre-process pressure, a process additive supply system and pump for supplying a process fluid additive to said process fluid, means for mixing said process fluid and said process fluid additive into a fluid mixture, and a heater for heating and maintaining said fluid mixture under said pre-process pressure at a pre-process temperature, said pre-process pressure and said pre-process temperature in combination placing said fluid mixture in supercritical phase,

(b) a process byproducts recovery system for collecting byproducts of said process, said recovery system including means for recovering said process fluid from said byproducts and returning said process fluid to said process fluid supply system,

(c) means for controlling temperature within said process chamber,

(d) an inflow valve for connecting said fluid delivery system to said process chamber for fluid flow,

(e) an outflow valve for connecting said process chamber to said recovery system for fluid flow,

(f) a bypass valve for connecting said fluid delivery system to said recovery system so as to bypass said process chamber, and

(g) a computer control system controlling said pump, said heater, said means for controlling temperature within said process chamber, and said valves, said valves being operable so as to provide continuous flow of said process fluid from said delivery system to said recovery system,

said recovery system further comprising means for recovering said process additives from said byproducts and returning said additives to said process additive supply system,

said means for controlling temperature with said process chamber comprising a liquid heating and cooling subsystem, inflow and outflow lines connecting said subsystem to at least one heat exchanger within said process chamber, and control valves for controlling flow in said heat exchanger, said subsystem and said control valves being controlled by said computer control system,

said process fluid being carbon dioxide, said supercritical phase process being the cleaning and processing of semiconductor wafers, and

the opening, loading and unloading, and closing of said process chamber being controlled by said computer control system.