Suspended gas distribution manifold for plasma chamber

• US 6,772,827 B2
• Filed: 08/03/2001
• Issued: 08/10/2004
• Est. Priority Date: 01/20/2000
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Shang, Quanyuan, Keller, Ernst
• Primary Examiner(s): Lund, Jeffrie R
• Assistant Examiner(s): Zervigon, Rudy
• Application Number:
  US09/922,219
• Publication Number:
  US 20020069968A1
• Time in Patent Office: 1,103 Days
• Field of Search: 165/47, 165/53, 165/9.3, 165/9.1, 295/250.2, 374/6, 118/715, 118/728, 118/50, 156/345.29, 156/345.33, 156/345.34, 156/345.35
• US Class Current: 165/53
• CPC Class Codes: C23C 16/455 characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/5096 Flat-bed apparatus
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: Y10T 29/49948 Multipart cooperating fastener [e.g., bolt and nut]

Abstract

A gas inlet manifold for a plasma chamber having a perforated gas distribution plate suspended by a side wall comprising one or more sheets. The sheets preferably provide flexibility to alleviate stress in the gas distribution plate due to thermal expansion and contraction. In another aspect, the side wall provides thermal isolation between the gas distribution plate and other components of the chamber.

Claims

1. A method of minimizing thermal stress on a gas distribution plate through which gas is dispensed into the interior of a plasma chamber, comprising the steps of:

providing a plasma chamber having an interior;

mounting an inlet manifold top wall within the chamber;

providing one or more inlet manifold side wall segments, wherein each side wall segment includes an upper portion, a lower flange, and a sheet extending between the upper portion of that side wall segment and the lower flange of that side wall segment;

mounting the upper portion of each segment of the inlet manifold side wall to the inlet manifold top wall so as to position the segments of the inlet manifold side wall so that they collectively encircle an inlet manifold region within the plasma chamber;

providing a gas distribution plate perforated by a number of gas outlet orifices;

mounting the lower flange of each side wall segment to the gas distribution plate so that the gas distribution plate is spaced away from the inlet manifold top wall, wherein the inlet manifold top wall, the inlet manifold side wall segments, and the gas distribution plate collectively enclose said inlet manifold region; and

supplying a gas through a gas inlet orifice in the inlet manifold top wall so that the gas flows into the inlet manifold region and then flows through the gas outlet orifices into the interior of the plasma chamber.

2. A method according to claim 1, further comprising the step of:

maintaining a plasma within the interior of the plasma chamber;

wherein the step of providing the inlet manifold side wall segments includes the step of providing each sheet with a thickness sufficiently small, and a height sufficiently large, so as to produce a substantial temperature differential between the inlet manifold top wall and the gas distribution plate in response to heat transferred from the plasma to the gas distribution plate.

3. A method according to claim 1, further comprising the step of:

maintaining a plasma within the interior of the plasma chamber;

wherein the step of providing the inlet manifold side wall segments includes the step of providing each sheet with a thickness sufficiently small, and a height sufficiently large, so as to produce a temperature differential of at least 100 degrees C. between the inlet manifold top wall and the gas distribution plate in response to heat transferred from the plasma to the gas distribution plate.

4. A method according to claim 1, wherein the step of providing the inlet manifold side wall segments includes the step of:

providing each sheet with a flexibility sufficient so that no substantial force is required to bend the sheet by an amount sufficient to permit the gas distribution plate to expand by at least one percent.

5. A method according to claim 1, wherein:

the inlet manifold top wall has a surface facing the gas distribution plate that is generally rectangular with four sides;

the gas distribution plate has a surface facing the top wall that is generally rectangular with four sides;

the step of providing the inlet manifold side wall segments comprises providing four of said side wall segments wherein the sheet of each of the four side wall segments is generally rectangular; and

the step of mounting the lower flange of each side wall segment comprises mounting each flange so that the sheet of each of the four side wall segments extends between a corresponding one of the four sides of said surface of the top wall and a corresponding one of the four sides of said surface of the gas distribution plate.

6. A method according to claim 1, wherein:

the gas distribution plate has one or more grooves in its perimeter; and

the step of mounting the lower flange of each side wall segment comprises mounting each such flange so as to extend into one of said grooves.

7. A method according to claim 1, wherein:

the gas distribution plate further comprises

a lip extending radially outward from the perimeter of the gas distribution plate, and

a plurality of pins attached to, and extending downward from, the lip of the gas distribution plate;

the lower flange of each side wall segment is perforated by a plurality of holes;

the step of mounting the lower flange of each side wall segment comprises mounting each flange to the gas distribution plate so that each of said pins extends through a corresponding one of said holes; and

each hole has a width that exceeds the width of its corresponding pin so as to permit relative movement between each lower flange and the gas distribution plate.

8. A method according to claim 7, wherein:

the sheet of each side wall segment is flexible so as to permit movement of the lower flange of that side wall segment in a direction perpendicular to the sheet; and

for each side wall segment, each hole in the lower flange of that side wall segment has a long axis parallel to the sheet of that side wall segment.

9. A method according to claim 7, wherein:

the width of each hole along one axis of the hole exceeds the width of its corresponding pin along said axis by an amount sufficient to permit an amount of relative movement between each lower flange and the gas distribution plate that exceeds the maximum likely relative differential thermal expansion between the lower flange and the gas distribution plate during operation of the plasma chamber.

10. A method according to claim 7, wherein:

the width of each hole along one axis of the hole exceeds the width of its corresponding pin along said axis by at least 0.03 inch.

11. A method according to claim 7, wherein:

the width of each hole along one axis of the hole exceeds the width of its corresponding pin along said axis by at least 0.1% of the widest dimension of the gas distribution plate.

12. A method according to claim 1, wherein:

said one or more side wall segments include first and second side wall segments; and

the method further comprises the steps of;

positioning an edge of the sheet of the first side wall segment and an edge of the sheet of the second side wall segment so as to be adjacent, parallel, and separated by a gap; and

mounting a post radially outward of the gap and sufficiently close to the gap so as to impede the flow of gas through the gap.

13. A method according to claim 1, wherein:

the step of providing one or more side wall segments includes providing first and second side wall segments;

the sheet of the first side wall segment is bent at a first angle along a first vertical vertex line so that;

(i) a first end area of the sheet extends between the first vertex line and an edge of the sheet, and (ii) a first central area of the sheet lies on the opposite side of the first vertex line;

the sheet of the second side wall segment is bent at a second angle along a second vertical vertex line so that;

(i) a second end area of the sheet extends between the second vertex line and an edge of the sheet, and (ii) a second central area of the sheet lies on the opposite side of the second vertex line;

the method further comprises the step of positioning said edge of the sheet of the first side wall segment and said edge of the sheet of the second side wall segment so as to be adjacent, parallel and separated by a gap; and

the first and second angles are established so that the first and second end areas are coplanar and are separated only by said gap.

14. A method according to claim 13, wherein both the first angle and the second angle are 45 degrees.

15. A method according to claim 13, further comprising the step of mounting a post radially outward of the gap, wherein:

the post extends vertically along the entire length of the gap;

the post extends laterally so as to overlie the first end area, the second end area, a portion of the first central area adjoining the first vertex line, and a portion of the second central area adjoining the second vertex line; and

the post is positioned sufficiently close to said portions of the first and second areas, and said portions of the first and second areas are sufficiently large, so that the post impedes gas within the inlet manifold from flowing through the gap.

20. A method according to claim 1, wherein the step of providing the inlet manifold side wall segments includes the step of:

providing each sheet with a thickness less than 3 millimeters.

21. A method according to claim 1, wherein the step of providing the inlet manifold side wall segments includes the step of:

providing each sheet with a thickness less than 1 millimeter.

22. A method according to claim 1, wherein the step of providing the inlet manifold side wall segments includes the step of:

providing each sheet with a flexibility sufficient to permit each sheet to bend at least 6.3 degrees.

23. A method according to claim 1, further comprising the steps of:

positioning a workpiece within the interior of the plasma chamber; and

maintaining a plasma within the interior of the plasma chamber;

wherein the step of providing the gas distribution plate includes the step of providing the gas distribution plate with a surface facing the workpiece; and

wherein the step of providing the inlet manifold side wall segments includes the step of providing each sheet with a flexibility sufficient so as to prevent the flatness of said surface of the gas distribution plate from being distorted by more than 25 microns in response to heat from the plasma.

24. A method according to claim 1, further comprising the steps of:

positioning a workpiece within the interior of the plasma chamber; and

maintaining a plasma within the interior of the plasma chamber;

wherein the step of providing the gas distribution plate includes the step of providing the gas distribution plate with a surface facing the workpiece; and

wherein the step of providing the inlet manifold side wall segments includes the step of providing each sheet with a flexibility sufficient so as to prevent the flatness of said surface of the gas distribution plate from being distorted by more than 10 microns in response to heat from the plasma.

16. A method of minimizing spatial variation in temperature of a gas distribution plate through which gas is dispensed into the interior of a plasma chamber, comprising the steps of:

providing a plasma chamber having an interior;

mounting an inlet manifold top wall within the chamber;

providing an inlet manifold side wall including one or more side wall segments, wherein each side wall segment includes an upper portion, a lower flange, and a sheet extending between the upper portion of that side wall segment and the lower flange of that side wall segment;

mounting the upper portion of each side wall segment to the inlet manifold top wall so as to position the side wall segments so that they collectively encircle an inlet manifold region within the plasma chamber;

providing a gas distribution plate perforated by a number of gas outlet orifices;

mounting the lower flange of each side wall segment to the gas distribution plate so that the gas distribution plate is spaced away from the top wall, wherein the inlet manifold top wall, the inlet manifold side wall segments, and the gas distribution plate collectively enclose said inlet manifold region; and

supplying a gas through a gas inlet orifice in the inlet manifold top wall so that the gas flows into the inlet manifold region and then flows through the gas outlet orifices into the interior of the plasma chamber; and

providing a plasma within the chamber;

wherein the inlet manifold side wall interposes a sufficiently high thermal resistance between the inlet manifold top wall and the gas distribution plate so that, during operation of the plasma chamber, the gas distribution plate has a spatial variation in temperature no greater than 50 degrees C.

17. A method according to claim 16, wherein said spatial variation in temperature is no greater than 10 degrees C.

18. A method of minimizing the difference in temperature between a workpiece support pedestal and a gas distribution plate through which gas is dispensed into the interior of a plasma chamber, comprising the steps of:

supporting a substrate on a pedestal within the plasma chamber;

heating the pedestal;

mounting an inlet manifold top wall within the chamber;

providing an inlet manifold side wall including one or more side wall segments, wherein each side wall segment includes an upper portion, a lower flange, and a sheet extending between the upper portion of that side wall segment and the lower flange of that side wall segment;

mounting the upper portion of each side wall segment to the inlet manifold top wall so as to position the side wall segments so that they collectively encircle an inlet manifold region within the plasma chamber;

providing a gas distribution plate perforated by a number of gas outlet oriflces;

mounting the lower flange of each side wall segment to the gas distribution plate so that the gas distribution plate is spaced away from the top wall, wherein the inlet manifold top wall, the inlet manifold side wall segments, and the gas distribution plate collectively enclose said inlet manifold region; and

supplying a gas through a gas inlet orifice in the inlet manifold top wall so that the gas flows into the inlet manifold region and then flows through the gas outlet orifices into the interior of the plasma chamber; and

providing a plasma within the chamber;

wherein the inlet manifold side wall interposes a sufficiently high thermal resistance between the inlet manifold top wall and the gas distribution plate so that, during the steps of heating the pedestal and providing a plasma within the chamber, there is a temperature difference between the pedestal and the upper surface of the substrate no greater than 50 degrees C.

19. A method according to claim 18, wherein said temperature difference is no greater than 25 degrees C.