O-ringless tandem throttle valve for a plasma reactor chamber

• US 20060237136A1
• Filed: 04/26/2005
• Published: 10/26/2006
• Est. Priority Date: 04/26/2005
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Ramaswamy, Kartik, Hanawa, Hiroji, Collins, Kenneth S., Nguyen, Andrew, Al-Bayati, Amir, Gallo, Biagio
• Granted Patent: US 7,428,915 B2
• Time in Patent Office: Days
• US Class Current: 156/345.290
• CPC Class Codes: F16K 1/22 with axis of rotation crossing the valve member, e.g. butterfly valves
• CPC Class Codes: F16K 1/223 with a plurality of valve members
• CPC Class Codes: F16K 1/526 for limiting the maximum flow rate, using a second valve
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow
• CPC Class Codes: Y10T 137/87531 Butterfly valve

Abstract

A valve system having high maximum gas flow rate and fine control of gas flow rate, includes a valve housing for blocking gas flow through a gas flow path, a large area opening through said housing having a first arcuate side wall and a small area opening through said housing having a second arcuate side wall, and respective large area and small area rotatable valve flaps in said large area and small area openings, respectively, and having arcuate edges congruent with said first and second arcuate side walls, respectively and defining therebetween respective first and second valve gaps. The first and second valve gaps are sufficiently small to block flow of a gas on one side of said valve housing up to a predetermined pressure limit, thereby obviating any need for O-rings.

Claims

1. A valve system having high maximum gas conductance and fine control of gas conductance, said valve system comprising:

a valve housing for limiting gas flow through a gas flow path;

a large area opening through said housing having a first arcuate side wall; and

a large area rotatable valve flap in said large area opening and having an arcuate edge congruent with said first arcuate side wall, respectively and defining therebetween a first valve gap.

2. The valve system of claim 1 further comprising:

a small area opening through said housing having a second arcuate side wall; and

a small area rotatable flap in said small area opening and having an arcuate edge congruent with said second arcuate side wall and defining therebetween a second valve gap.

3. The valve system of claim 1 wherein said first valve gap is sufficiently small to limit gas conductance of said valve housing up to a predetermined pressure limit at a predetermined gas flow rate.

4. The valve system of claim 2 wherein said first and second valve gaps are sufficiently small to limit gas conductance of said valve housing up to a predetermined pressure limit at a predetermined minimum gas flow rate.

5. The valve system of claim 4 wherein said predetermined pressure limit is about 200 mT wherein said minimum gas flow rate is about 10 sccm.

6. The valve system of claim 3 wherein said first valve gap is less than a mean collision path length of the gas within said predetermined pressure limit.

7. The valve system of claim 4 wherein said valve gaps are less than a mean collision path length of said gas within said predetermined pressure limit.

8. The valve system of claim 1 further comprising:

plural slots in said side walls of said large area opening.

9. The valve system of claim 8 wherein said plural slots comprise arcuate holes in said side wall extending from one face of said valve housing and having a depth that is maximum at one face of said side wall and tapers to a minimum or zero depth at a predetermined distance below said one face of said valve housing.

10. The valve system of claim 9 further comprising plural slots extending from the opposite face of said valve housing and comprising arcuate holes in said side wall having a depth that is maximum at said opposite face of said side wall and tapers to a minimum or zero depth at a predetermined distance below said opposite face.

11. The valve system of claim 10 wherein the plural slots extending from said one face and the plural slots extending from said opposite face are separated by an unslotted region of said side wall.

12. A valve assembly for controlling one of gas conductance from a plasma reactor chamber to a vacuum pump or chamber pressure, said valve assembly comprising:

a valve housing having first and second opposing surfaces;

a high conductance valve comprising;

a large area opening in said first and second opposing surfaces and extending through said valve housing, said opening defining a side wall extending between said first and second surfaces having an arcuate cross-section,

a large area rotatable flap in said large area opening having a peripheral edge with an arcuate cross-section generally matching that of said side wall and defining a small gap between said peripheral edge and said side wall in a closed flap position;

a fine control valve comprising;

a small area opening in said first and second opposing surfaces and extending through said valve housing, said opening defining a side wall extending between said first and second surfaces having an arcuate cross-section; and

a small area rotatable flap in said small area opening having a peripheral edge with an arcuate cross-section generally matching that of said side wall and defining a small gap between said peripheral edge and said side wall in a closed flap position.

13. The apparatus of claim 12 wherein each said small gap is sufficiently small to limit gas conductance through said valve assembly within a predetermined pressure range at a predetermined minimum gas flow rate.

14. The apparatus of claim 13 wherein said pressure range extends up to about 200 mT wherein said minimum gas flow rate is about 10 sccm.

15. The apparatus of claim 12 wherein each said small gap is on the order of about twenty thousandths of an inch.

16. The apparatus of claim 12 wherein each said gap is less than the mean collision path length of a plasma in said reactor chamber within a selected pressure range of said reactor chamber.

17. The valve system of claim 12 further comprising:

plural slots in said side walls of said large area opening.

18. The valve system of claim 17 wherein said plural slots comprise arcuate holes in said side wall extending from one face of said valve housing and having a depth that is maximum at one face of said side wall and tapers to a minimum or zero depth at a predetermined distance below said one face of said valve housing.

19. The valve system of claim 18 further comprising plural slots extending from the opposite face of said valve housing and comprising arcuate holes in said side wall having a depth that is maximum at said opposite face of said side wall and tapers to a minimum or zero depth at a predetermined distance below said opposite face.

20. A pressure control system, comprising:

a plasma reactor chamber;

a process gas supply to said chamber having a predetermined gas flow rate;

an evacuation pump;

a pressure sensor coupled to the chamber;

a valve coupled between said chamber and said evacuation pump, said valve having high maximum gas conductance and fine control of gas conductance, said valve comprising;

(a) a valve housing for limiting gas flow through a gas flow path,

(b) a large area opening through said housing having a first arcuate side wall,

(c) a large area rotatable valve flap in said large area opening, and having an arcuate edge congruent with said first arcuate side wall, respectively, and defining therebetween a first valve gap; and

a feedback control system coupled to said pressure sensor and to said rotatable valve flap for controlling pressure within said chamber.