Thermal management systems and methods for wafer processing systems

• US 9,741,593 B2
• Filed: 08/06/2015
• Issued: 08/22/2017
• Est. Priority Date: 08/06/2015
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Benjaminson, David, Lubomirsky, Dmitry
• Primary Examiner(s): Wilson, Lee D
• Application Number:
  US14/820,365
• Publication Number:
  US 20170040190A1
• Time in Patent Office: 747 Days
• CPC Class Codes: H01L 21/3247 for altering the shape, e.g. smoothing the surface
• CPC Class Codes: H01L 21/67103 mainly by conduction
• CPC Class Codes: H01L 21/68785 characterised by the mechanical construction of the susceptor, stage or support
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14

Abstract

A workpiece holder includes a puck having a cylindrical axis, a radius about the cylindrical axis, and a thickness. At least a top surface of the puck is substantially planar, and the puck defines one or more thermal breaks. Each thermal break is a radial recess that intersects at least one of the top surface and a bottom surface of the cylindrical puck. The radial recess has a thermal break depth that extends through at least half of the puck thickness, and a thermal break radius that is at least one-half of the puck radius. A method of processing a wafer includes processing the wafer with a first process that provides a first center-to-edge process variation, and subsequently, processing the wafer with a second process that provides a second center-to-edge process variation that substantially compensates for the first center-to-edge process variation.

Claims

1. A workpiece holder that positions a workpiece for processing, the workpiece holder comprising:

a substantially cylindrical puck that is characterized by a cylindrical axis, a puck radius about the cylindrical axis, and a puck thickness,

wherein the puck radius is at least four times the puck thickness,

wherein at least a top surface of the cylindrical puck is substantially planar, and

wherein the cylindrical puck defines one or more radial thermal breaks,

each thermal break being characterized as a radial recess that intersects at least one of the top surface and a bottom surface of the cylindrical puck, wherein the radial recess is characterized by;

a thermal break depth that extends from the top surface or the bottom surface of the puck through at least half of the puck thickness,

and a thermal break radius that is disposed symmetrically about the cylindrical axis, and is at least one-half of the puck radius;

and wherein the radial recess intersects the top surface, the workpiece holder further comprising at least three lifting elements that extend above the top surface in an extended state, to lift the workpiece from the top surface, and that retract into the radial recess in a retracted state, to lower the workpiece onto the top surface.

2. The workpiece holder of claim 1, further comprising:

a first heating device disposed adjacent to the bottom surface of the puck and radially inward from the one or more thermal breaks relative to the cylindrical axis, the first heating device being in thermal contact with the bottom surface of the puck within the thermal break radius, and

a second heating device disposed adjacent to the bottom surface of the puck and radially outward from the one or more thermal breaks relative to the cylindrical axis, the second heating device being in thermal contact with the bottom surface of the puck outside the thermal break radius.

3. The workpiece holder of claim 2, wherein at least one of the first and second heating devices comprises a heater element trace that is disposed within a plurality of electrically insulating layers.

4. A workpiece holder that positions a workpiece for processing, the workpiece holder comprising:

a substantially cylindrical puck that is characterized by a cylindrical axis, a puck radius about the cylindrical axis, and a puck thickness, wherein;

the puck radius is at least four times the puck thickness,

at least a top surface of the cylindrical puck is substantially planar, and

the cylindrical puck defines one or more radial thermal breaks,

each thermal break being characterized as a radial recess that intersects at least one of the top surface and a bottom surface of the cylindrical puck, wherein the radial recess is characterized by;

a thermal break depth that extends from the top surface or the bottom surface of the puck through at least half of the puck thickness,

and a thermal break radius that is disposed symmetrically about the cylindrical axis, and is at least one-half of the puck radius;

a first heating device disposed adjacent to the bottom surface of the puck and radially inward from the one or more thermal breaks relative to the cylindrical axis, the first heating device being in thermal contact with the bottom surface of the puck within the thermal break radius; and

a second heating device disposed adjacent to the bottom surface of the puck and radially outward from the one or more thermal breaks relative to the cylindrical axis, the second heating device being in thermal contact with the bottom surface of the puck outside the thermal break radius;

wherein;

at least one of the first and second heating devices comprises a heater element trace that is disposed within a plurality of electrically insulating layers,

the heater element trace comprises a resistive material, and

at least one of the electrically insulating layers comprises polyimide.

5. The workpiece holder of claim 4, wherein the radial recess is characterized by a thermal break radius that is at least 60% of the puck radius.

6. The workpiece holder of claim 4, wherein the heater element trace and the electrically insulating layers are disposed within a plurality of metal layers.

7. A workpiece holder that positions a workpiece for processing, the workpiece holder comprising:

a substantially cylindrical puck that is characterized by a cylindrical axis, a puck radius about the cylindrical axis, and a puck thickness, wherein;

the puck radius is at least four times the puck thickness,

at least a top surface of the cylindrical puck is substantially planar, and

the cylindrical puck defines one or more radial thermal breaks,

each thermal break being characterized as a radial recess that intersects at least one of the top surface and a bottom surface of the cylindrical puck, wherein the radial recess is characterized by;

a thermal break depth that extends from the top surface or the bottom surface of the puck through at least half of the puck thickness,

and a thermal break radius that is disposed symmetrically about the cylindrical axis, and is at least one-half of the puck radius;

a first heating device disposed adjacent to the bottom surface of the puck and radially inward from the one or more thermal breaks relative to the cylindrical axis, the first heating device being in thermal contact with the bottom surface of the puck within the thermal break radius;

a second heating device disposed adjacent to the bottom surface of the puck and radially outward from the one or more thermal breaks relative to the cylindrical axis, the second heating device being in thermal contact with the bottom surface of the puck outside the thermal break radius; and

a thermal sink that extends substantially across the bottom surface of the cylindrical puck, the first and second heating devices being disposed between the thermal sink and the bottom surface of the cylindrical puck.

8. The workpiece holder of claim 7, wherein the thermal sink comprises a metal plate that defines one or more fluid channels.

9. The workpiece holder of claim 7, wherein:

the first and second heating devices comprise respective first and second heater element traces that are disposed between first and second electrically insulating layers;

the first electrically insulating layer is disposed between the first and second heater element traces and the thermal sink;

the second electrically insulating layer is disposed between the first and second heater element traces and the bottom surface of the cylindrical puck; and

the first electrically insulating layer is thicker than the second electrically insulating layer, such that the first electrically insulating layer increases thermal resistance between the heater element traces and the thermal sink so that when the heater element traces supply heat, more of the heat transfers to the puck than to the thermal sink.

10. The workpiece holder of claim 9, wherein the first one of the electrically insulating layers comprises ceramic.

11. The workpiece holder of claim 9, further comprising:

first and second metal layers; and

first and second thermally stable polymer layers;

and wherein the workpiece holder is bonded together, with the elements and layers disposed in the following physical order from bottom to top;

the thermal sink;

the first thermally stable polymer layer;

the first metal layer;

the first electrically insulating layer;

the first and second heater element traces at the same level, the second heater element trace being radially outward from the first heater element trace;

the second electrically insulating layer;

the second metal layer;

the second thermally stable polymer layer; and

the puck.

12. The workpiece holder of claim 7, wherein the cylindrical puck defines two of the radial thermal breaks;

a first one of the radial thermal breaks being characterized as a radial recess that intersects the top surface of the cylindrical puck, the thermal break depth of the first one of the radial thermal breaks extending downwardly from the top surface of the puck through more than half of the puck thickness; and

a second one of the radial thermal breaks being characterized as a radial recess that intersects the bottom surface of the cylindrical puck, the thermal break depth of the second one of the radial thermal breaks extending upwardly from the bottom surface of the puck through more than half of the puck thickness.

13. A workpiece holder that positions a workpiece for processing, the workpiece holder comprising:

a substantially cylindrical puck that is characterized by a cylindrical axis and a substantially planar top surface, wherein the cylindrical puck defines two radial thermal breaks,

a first one of the thermal breaks being characterized as a radial recess that intersects a bottom surface of the cylindrical puck at a first radius, and extends from the bottom surface through at least one-half of a thickness of the puck;

a second one of the thermal breaks being characterized as a radial recess that intersects the top surface at a second radius that is greater than the first radius, and extends from the top surface through at least one-half of the thickness of the puck;

a thermal sink that extends substantially beneath the bottom surface of the puck, the thermal sink comprising a metal plate that flows a heat exchange fluid through channels defined therein, to maintain a reference temperature for the puck;

a first heating device disposed between the thermal sink and the puck, the first heating device being in thermal communication with the bottom surface of the puck and with the thermal sink, within the first radius; and

a second heating device disposed between the thermal sink and the puck, the second heating device being in thermal communication with the bottom surface of the puck and with the thermal sink, outside the second radius.

14. The workpiece holder of claim 13, wherein:

the first and second heating devices comprise respective first and second heater element traces that are disposed between first and second electrically insulating layers.

15. The workpiece holder of claim 14, wherein:

the first electrically insulating layer is disposed between the first and second heater element traces and the thermal sink;

the second electrically insulating layer is disposed between the first and second heater element traces and the bottom surface of the cylindrical puck; and

the first electrically insulating layer is thicker than the second electrically insulating layer, such that the first electrically insulating layer increases thermal resistance between the heater element traces and the thermal sink so that when the heater element traces supply heat, more of the heat transfers to the puck than to the thermal sink.

16. The workpiece holder of claim 14, wherein the first one of the electrically insulating layers comprises ceramic.

17. The workpiece holder of claim 14, further comprising:

first and second metal layers; and

first and second thermally stable polymer layers;

and wherein the workpiece holder is bonded together, with the elements and layers disposed in the following physical order from bottom to top;

the thermal sink;

the first thermally stable polymer layer;

the first metal layer;

the first electrically insulating layer;

the first and second heater element traces at the same level, the second heater element trace being radially outward from the first heater element trace;

the second electrically insulating layer;

the second metal layer;

the second thermally stable polymer layer; and

the puck.