Showerhead mounting to accommodate thermal expansion

• US 20050183827A1
• Filed: 02/23/2005
• Published: 08/25/2005
• Est. Priority Date: 02/24/2004
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: White, John M., Sterling, William Norman
• Granted Patent: US 7,722,925 B2
• Time in Patent Office: Days
• US Class Current: 156/345.340
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32522 Temperature

Abstract

Methods and apparatus for accommodating thermal expansion of a showerhead. In a first aspect of the invention, the showerhead is movably supported by resting a rim of the showerhead on a support shelf. In a second aspect, the showerhead is suspended from the chamber wall by a plurality of hangers that are connected to the showerhead, the chamber wall, or both by pins that slide within slots so as to permit the hangers to slide radially to accommodate thermal expansion of the showerhead in the radial direction. In a third aspect, the showerhead is suspended from the wall of the vacuum chamber by a plurality of rods or flexible wires. In a fourth aspect, the showerhead is connected near its perimeter to a second material having a greater thermal expansion coefficient than the showerhead. In a fifth aspect, a heater is mounted behind the showerhead to reduce the termperature differential between the top and bottom surfaces of the showerhead or to reduce heat transfer from the workpiece to the showerhead.

Claims

1. A method of dispensing gas into a vacuum chamber, comprising the steps of:

providing a vacuum chamber having a chamber wall that encloses a chamber interior;

positioning a shelf within the chamber interior, wherein the shelf has an upward facing surface;

providing a showerhead having a circumferential rim, an upper surface, a lower surface, and one or more gas orifices extending between the upper surface and the lower surface, wherein the rim of the showerhead includes a downward facing surface;

positioning the showerhead within the chamber interior so that the downward facing surface of the rim of the showerhead rests on the upward facing surface of the shelf and so that the rim of the showerhead is free to slide along the upward facing surface of the shelf; and

flowing gas through the gas orifices of the showerhead into the chamber interior.

2. A method according to claim 1, wherein the mounting step further comprises:

covering a surface of the chamber wall that faces the chamber interior with a dielectric liner;

wherein the dielectric liner includes said shelf.

3. A method according to claim 1, wherein:

the showerhead is rectangular;

the rim is rectangular and has four sides; and

the shelf comprises four distinct pieces that respectively abut the four respective sides of the rim.

4. A method according to claim 1, wherein the shelf is one continuous piece.

5. A method according to claim 1, wherein:

the shelf comprises a plurality of pieces separated by gaps; and

the gaps between adjacent pieces of the shelf have a combined cross-sectional area that is less than one-tenth of the combined cross-sectional area of the narrowest portion of each of the outlet orifices of the showerhead.

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

providing one or more gas inlet orifices within the chamber wall;

providing said shelf so that said shelf comprises a plurality of pieces; and

connecting an outer portion of each piece of the shelf to the chamber wall so that the chamber wall, the showerhead, and the pieces of the shelf collectively enclose a volume that is in fluid communication with the gas inlet orifices of the chamber wall and the gas outlet orifices of the showerhead;

wherein the step of flowing gas through the gas orifices of the showerhead comprises the step of flowing an amount of gas through the gas inlet orifices into said volume; and

wherein adjacent pieces of the shelf are separated by gaps that are sufficiently small so that, during the step of flowing said amount of gas through the gas inlet orifices, at least ninety percent of said amount of gas flows through the gas outlet orifices.

7. A method according to claim 1, wherein:

the chamber wall includes a gas inlet manifold top wall having at least one gas inlet orifice; and

the step of positioning said shelf includes the step of providing a hanger having an upper portion connected to the gas inlet manifold top wall and having a lower portion connected to the shelf.

8. A method according to claim 7, wherein the gas inlet manifold top wall, the hanger, the shelf, the showerhead rim, and the showerhead are each electrically conductive and are connected together in series so as to provide an electrically conductive connection between the gas inlet manifold top wall and the showerhead.

9. A method of dispensing gas into a vacuum chamber, comprising the steps of:

providing a vacuum chamber having a chamber wall that encloses a chamber interior, wherein the chamber wall includes a gas inlet manifold top wall having at least one gas inlet orifice;

providing a showerhead having one or more gas orifices;

providing a first hanger layer including one or more hangers, wherein each hanger includes an upper portion and a lower portion;

connecting the upper portion of each hanger to the gas inlet manifold top wall;

providing a plurality of sliding joints, wherein each sliding joint comprises a pin slidable within a slot;

connecting the lower portion of each hanger of the first hanger layer to the showerhead by at least one sliding joint so as to enable relative sliding motion between each hanger of the first hanger layer and the showerhead and so that the hangers of the first hanger layer support the showerhead within the vacuum chamber; and

flowing gas through the gas orifices of the showerhead into the chamber interior.

10. A method according to claim 9, wherein:

the pin of each sliding joint is connected to and extends downward from the lower portion of one of the hangers; and

the slot of each sliding joint is formed in the showerhead.

11. A method according to claim 10, wherein:

each pin includes a shoulder that is wider than the transverse width of the slot within which it slides; and

the showerhead rests on the shoulders of the pins.

12. A method according to claim 9, wherein:

the pin of each sliding joint is connected to and extends upward from the showerhead; and

the slot of each sliding joint is formed in the lower portion of one of the hangers.

13. A method according to claim 12, wherein:

each slot is bounded by a slot side wall in the lower portion of the hanger in which the slot is formed;

each pin includes a shoulder that is wider than the transverse width of the slot within which it slides; and

the shoulder of each pin rests on the side wall of the slot within which it slides.

14. A method according to claim 9, wherein the sliding joints are connected to the showerhead at distributed locations near the perimeter of the showerhead.

15. A method according to claim 9, wherein:

the showerhead is characterized by a longitudinal axis; and

each slot has a longest dimension oriented perpendicular to the longitudinal axis of the showerhead.

16. A method according to claim 9, wherein the step of connecting the lower portion of each hanger of the first hanger layer comprises:

connecting the upper portion of each hanger of the first hanger layer directly to the gas inlet manifold top wall.

17. A method according to claim 9, wherein the step of connecting the lower portion of each hanger of the first hanger layer comprises:

slidably connecting the upper portion of each hanger of the first hanger layer to the gas inlet manifold top wall.

18. A method according to claim 9, wherein the step of connecting the lower portion of each hanger of the first hanger layer comprises:

connecting the upper portion of each hanger of the first hanger layer to the gas inlet manifold top wall by one or more sliding joints that permit relative motion between each hanger of the first hanger layer and the gas inlet manifold top wall.

19. A method according to claim 9, further comprising the steps of:

providing a second hanger layer including one or more hangers, each hanger of the second layer includes an upper portion and a lower portion;

connecting the upper portion of each hanger of the second layer to the gas inlet manifold top wall; and

connecting the lower portion of each hanger of the second layer to the upper portion of a corresponding one of the hangers of the first layer by at least one sliding joint so as to permit relative sliding motion between each hanger of the first hanger layer and the its corresponding hanger of the first layer and so that the hangers of the second hanger layer support the hangers of the first hanger layer.

20. A method of dispensing gas into a vacuum chamber, comprising the steps of:

providing a vacuum chamber having a chamber wall that encloses a chamber interior, wherein the chamber wall includes a gas inlet manifold top wall having at least one gas inlet orifice;

providing a showerhead having one or more gas orifices;

providing a first hanger layer including one or more hangers, wherein each hanger includes an upper portion and a lower portion;

providing a plurality of sliding joints, wherein each sliding joint comprises a pin slidable within a slot;

connecting the upper portion of each hanger of the first hanger layer to the gas inlet manifold top wall by at least one sliding joint so as to permit relative sliding motion between each hanger of the first hanger layer and the gas inlet manifold top wall and so that the gas inlet manifold top wall supports the hangers,of the first hanger layer;

connecting the lower portion of each hanger to the showerhead so that the hangers of the first hanger layer support the showerhead within the vacuum chamber; and

flowing gas through the gas orifices of the showerhead into the chamber interior.