Method for continuously blending chemical solutions

• US 6,799,883 B1
• Filed: 12/20/1999
• Issued: 10/05/2004
• Est. Priority Date: 12/20/1999
• Status: Expired due to Term

• Current Assignee: Air Liquide America LP (Mitsubishi Chemical Group Corp.)
• Original Assignee: Air Liquide America LP (Mitsubishi Chemical Group Corp.)
• Inventors: Urquhart, Karl J., Thompson, John B., Hoffman, Joe G.
• Primary Examiner(s): Sorkin, David
• Application Number:
  US09/468,411
• Time in Patent Office: 1,751 Days
• Field of Search: 366/151.1, 366/152.1, 366/152.4, 366/162.1, 137/3, 137/5
• US Class Current: 366/152.4
• CPC Class Codes: B01F 35/2133 Electrical conductivity or dielectric constant of the mixture
• CPC Class Codes: B01F 35/82 by adding a material to be mixed to a mixture in response to a detected feature, e.g. density, radioactivity, consumed power or colour
• CPC Class Codes: H01L 21/02052 Wet cleaning only H01L21/02085 takes precedence
• CPC Class Codes: H01L 21/30604 Chemical etching
• CPC Class Codes: H01L 21/30608 Anisotropic liquid etching H01L21/3063 takes precedence
• CPC Class Codes: Y10T 137/0329 Mixing of plural fluids of diverse characteristics or conditions
• CPC Class Codes: Y10T 137/034 Controlled by conductivity of mixture
• CPC Class Codes: Y10T 137/2509 By optical or chemical property

Abstract

Provided are a method and apparatus for continuously blending a chemical solution for use in semiconductor processing. The method involves the step of: mixing a first chemical stream with a second chemical stream in a controlled manner, to form a stream of a solution having a predetermined formulation. The apparatus allows one to practice the above method. The method and apparatus can accurately provide chemical solutions of desired concentration in a continuous manner. The invention has particular applicability in semiconductor device fabrication.

Claims

1. A method of continuously blending a chemical solution for use in semiconductor processing, comprising:

mixing continuously a first chemical stream with a second chemical stream in a mixing zone in a conduit system and in a real time controlled manner forming a solution having a predetermined formulation, wherein the first chemical stream and the second chemical stream are continuously introduced to the mixing zone;

adjusting continuously the flowrate of the first chemical and the flowrate of the second chemical;

monitoring continuously the solution; and

introducing the solution having a predetermined formulation into a semiconductor processing tool.

2. The method according to claim 1, wherein the flowrate of the first chemical or the flowrate of the second chemical is controlled in response to a signal generated by a sensor which monitors the solution.

3. The method according to claim 2, wherein the sensor is selected from a group consisting of conductivity and acoustic signature sensors.

4. The method according to claim 3, wherein the solution is ionic, and the sensor is a conductivity sensor.

5. The method according to claim 4, wherein the conductivity sensor is an electrodeless conductivity sensor employing AC toroid coils.

6. The method according to claim 3, wherein the solution is non-ionic, and the sensor is an acoustic signature sensor.

7. The method according to claim 1, wherein the first chemical or the second chemical is deionized water.

8. The method according to claim 1, wherein the first and second chemicals are generated on-site.

9. The method according to claim 1, wherein the solution having a predetermined formulation is directly introduced into a semiconductor processing tool.

10. A method of continously blending a chemical solution for use in semiconductor processing, comprising the steps of:

(a) mixing a first chemical with a second chemical in a first mixing zone in a conduit system and in a real time controlled manner to provide a first solution having a predetermined formulation;

the flowrate of the first chemical and the flowrate of the second chemical are continuously adjusted;

the first solution formulation is continuously monitored; and

(b) mixing a third chemical with the first solution in a second mixing zone in said conduit system and in a real time controlled manner to provide a second solution having a predetermined formulation;

the flowrate of the third chemical is continuously adjusted;

second solution formulation is continuously monitored, wherein steps (a) and (b) are preformed contemporaneously.

11. The method according to claim 10 wherein step (a), the flowrate of the first chemical or the second chemical is controlled in response to a signal generated by a first sensor which monitors the first solution, and in step (b), the flowrate of the third chemical or the first solution is controlled in response to a signal generated by a second sensor with monitors the second solution.

12. The method according to claim 11, wherein the first sensor and the second sensor are of the same or different types, and are selected from the group consisting of conductivity sensors and acoustic signature sensors.

13. The method according to claim 12, wherein the first sensor and/or the second sensor is an AC toroid coil sensor.

14. The method according to claim 12, wherein the first solution and the second solution are ionic solutions, and the first sensor and the second sensor are conductivity sensors.

15. The method according to claim 14, wherein the conductivity sensor is an electrodeless conductivity sensor employing AC toroid coils.

16. The method according to claim 12, wherein one of the first solution and the second solution is a non-ionic solution and the other of the first solution and the second solution is an ionic solution.

17. The method according to claim 10, wherein the first chemical or the second chemical is deionized water.

18. The method according to claim 10, further comprising:

(a) mixing a fourth chemical with the second solution in a real time controlled manner to provide a third solution having a predetermined formulation;

the flowrate of the first chemical and the flowrate to the second solution are continuously adjusted;

the third solution is continuously monitored; and

wherein steps (a) and (b) are performed contemporaneously.

19. The method according to claim 10, wherein the second solution having a predetermined formulation is directly introduced into a semiconductor processing tool.

20. The method according to claim 10, wherein the second mixing zone is arranged downstream from the first mixing zone.

21. A method of continuously blending a chemical solution on-site at a semiconductor manufacturing facility, comprising the steps of:

(a) mixing a first chemical with a second chemical in a first mixing zone in a conduit system and in a real time controlled manner to provide a first solution having a predetermined formulation;

the flowrate of the first chemical and the flowrate of the second chemical are continuously adjusted;

the first solution is continuously monitored, and

(b) mixing a third chemical with the first solution in a second mixing zone in said conduit system and in a real time controlled manner to provide a second solution having a predetermined formulation;

the flowrate of the third chemical is continuously adjusted;

the second solution formulation is continuously monitored, and

(c) introducing the second solution having a predetermined formulation into a semiconductor processing tool, wherein steps (a) and (b) are performed contemporaneously.

22. The method according to claim 21, further comprising the steps (b), (c), and a step (b′

) mixing a fourth chemical with the second solution in a real time controlled manner to provide a third solution having a predetermined formulation,

(b) the flowrate of the fourth chemical is continuously adjusted;

the third solution formulation is continuously monitored, and wherein step (b) is performed contemporaneously with steps (a) and (b).

23. The method according to claim 21, wherein the second solution having a predetermined formulation is directly introduced into a semiconductor processing tool.