METHOD AND APPARATUS FOR CONTROLLING TEMPERATURE OF A SUBSTRATE

• US 20070139856A1
• Filed: 09/13/2006
• Published: 06/21/2007
• Est. Priority Date: 10/07/2004
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Holland, John, Gani, Nicolas, Katz, Dan, Hegarty, Michael, Panagopoulos, Theodoros, Matyushkin, Alexander, Koosau, Denis
• Granted Patent: US 7,436,645 B2
• Time in Patent Office: Days
• US Class Current: 361/234
• CPC Class Codes: H01L 21/67103 mainly by conduction
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/6831 using electrostatic chucks

Abstract

A pedestal assembly and method for controlling temperature of a substrate during processing is provided. In one embodiment, the pedestal assembly includes an electrostatic chuck coupled to a metallic base. The electrostatic chuck includes at least one chucking electrode and metallic base includes at least two fluidly isolated conduit loops disposed therein. In another embodiment, the pedestal assembly includes a support member that is coupled to a base by a material layer. The material layer has at least two regions having different coefficients of thermal conductivity. In another embodiment, the support member is an electrostatic chuck. In further embodiments, a pedestal assembly has channels formed between the base and support member for providing cooling gas in proximity to the material layer to further control heat transfer between the support member and the base, thereby controlling the temperature profile of a substrate disposed on the support member.

Claims

1. A substrate pedestal assembly comprising:

an electrostatic chuck having at least one chucking electrode disposed therein;

a metallic base coupled to a bottom surface of the electrostatic chuck;

an aperture extending through at least one of the base or the electrostatic chuck; and

a fluid conduit disposed in at least one of the electrostatic chuck and the base, wherein the fluid conduit includes a segment wrapping around the aperture.

2. The substrate pedestal assembly of claim 1 further comprising:

electrical conductors coupled to the electrostatic chuck and extending through the aperture.

3. The substrate pedestal assembly of claim 1 further comprising:

at least one backside gas channel formed in a substrate supporting surface of the electrostatic chuck and coupled to the aperture.

4. The substrate pedestal assembly of claim 1, wherein the aperture further comprises:

one of a plurality of lift pin holes formed through the base and electrostatic chuck, the lift pin holes arranged in a polar array.

5. The substrate pedestal assembly of claim 1, wherein the fluid conduit further comprises:

an inlet and an outlet, and wherein a portion of the fluid conduit extending from the inlet further comprise a loop portion having an end, such that a conduit length A defined from the end of the loop portion to the inlet is substantially equal to a conduit length B defined from the outlet to a position radially adjacent the end of the loop.

6. The substrate pedestal assembly of claim 5, wherein the length of conduit length A is within 10 percent of the length of conduit length B.

7. The substrate pedestal assembly of claim 1, wherein the fluid conduit further comprises:

midpoint defined between an inlet and an outlet of the fluid conduit, wherein a first portion of the fluid conduit is defined between the midpoint and the outlet, and a second portion of the fluid conduit is defined between the midpoint and the outlet, the first portion tracking the second portion of the fluid conduit in a spaced-apart relation; and

wherein a first length A defined from the midpoint of the conduit to a first position is substantially equal to a second length B defined from the midpoint of the conduit to a second position radially outward of the first position.

8. The substrate pedestal assembly of claim 7, wherein the length of first length A is within 10 percent of the length of second length B.

9. The substrate pedestal assembly of claim 1 further comprising:

a second aperture formed through the base, wherein the fluid conduit includes a second segment wrapping around the second aperture.

10. The substrate pedestal assembly of claim 9, wherein the first aperture further comprises:

one of a plurality of lift pin holes formed through the base and electrostatic chuck, the lift pin holes arranged in a polar array, and wherein the second aperture further comprises;

a backside gas delivery hole or an electrical conduit for lead coupled to the electrostatic chuck.

11. The substrate pedestal assembly of claim 1, wherein the fluid conduit further comprises:

a major radius of curvature substantially defining a path of the fluid conduit through the base; and

a minor radius of curvature defining a path of the segment, wherein the major radius is substantially greater than the minor radius.

12. The substrate pedestal assembly of claim 1 further comprising:

an insert disposed between adjacent portions of the fluid conduit and having a coefficient of thermal conductivity less than a coefficient of thermal conductivity of the base.

13. The substrate pedestal assembly of claim 1 further comprising:

a second fluid conduit formed in the base radially inward of the fluid conduit.

14. A substrate pedestal assembly comprising:

an electrostatic chuck having at least one chucking electrode disposed between a substrate supporting surface and a bottom surface;

a metallic base having a top surface coupled to the bottom surface of the electrostatic chuck, at least one of the electrostatic chuck or the base having a void defined therein; and

a fluid conduit disposed in the base and arranged substantially parallel to the top surface, the fluid conduit having a major curvature oriented about a center of the base and a minor curvature oriented about the aperture.

15. The substrate pedestal assembly of claim 14, wherein the major curvature has a radius substantially greater than a radius of the minor curvature.

16. The substrate pedestal assembly of claim 14 further comprising:

electrical conductors coupled to the electrostatic chuck and extending through the void.

17. The substrate pedestal assembly of claim 14 further comprising:

at least one backside gas channel formed in a substrate supporting surface of the electrostatic chuck and fluidly coupled to the void.

18. The substrate pedestal assembly of claim 14, wherein the void further comprises:

one of a plurality of lift pin holes formed through the base and electrostatic chuck, the lift pin holes arranged in a polar array.

19. A substrate pedestal assembly comprising:

a ceramic electrostatic chuck having at least one chucking electrode disposed between a substrate supporting surface and a bottom surface;

a metallic base coupled to the bottom surface of the electrostatic chuck;

a plurality of lift pin holes extending through the electrostatic chuck and base; and

a fluid conduit loop disposed in the base in a generally spiral orientation, wherein the fluid conduit includes a segment defined adjacent at least one of the lift pin holes that has an orientation centered around the lift pin hole.

20. The substrate pedestal assembly of claim 19 further comprising:

a first void having AC lead coupled to the electrostatic chuck, the first void positioned outside the loop and having a segment of the fluid conduit wrapping thereround;

a second void having DC lead coupled to the electrostatic chuck, the second void positioned inside the loop and having a segment of the fluid conduit wrapping thereround; and

third void providing a backside gas channel to the substrate supporting surface of the electrostatic chuck, the third void positioned outside the loop and having a segment of the fluid conduit wrapping thereround.

21. The substrate pedestal assembly of claim 19, wherein the segment has a constant radius.