High temperature multi-layered alloy heater assembly and related methods
First Claim
1. A substrate processing apparatus comprising:
- a chamber;
a heater power system; and
a heater assembly having, an inner core of a first metal, an outer shell of a second metal surrounding said inner core and including a surface for supporting a substrate, and a resistive heating element symmetrically disposed between an upper surface and a lower surface of said outer shell, said first metal having a higher thermal conductivity than said second metal.
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Accused Products
Abstract
The present invention provides systems, methods and apparatus for heating substrates in a processing chamber to temperatures up to at least 700° C. In accordance with an embodiment of the invention a heater assembly with an inner core of high thermal conductivity is encased in a shell of lower thermal conductivity, creating a nearly isothermal interface between the core and shell. The inner core is brazed to the shell, promoting thermal transfer, and acts as a thermal short between opposing surfaces of the shell. The heater assembly is designed to minimize thermal stresses arising from the difference in the thermal expansion coefficients of the various components of the multi-layered heater assembly. In one embodiment of the invention, two independently-powered heating elements are arranged concentrically to each other to create a dual zone heater. A thermal gap in the inner core between the inner and outer heating elements de-couples the zones and provides a more controllable temperature profile at the surface of the heater, including excellent temperature uniformity. In one embodiment, an RF isolator is placed between a heater and a support shaft, allowing the heater to be powered as an electrode in a plasma process.
784 Citations
11 Claims
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1. A substrate processing apparatus comprising:
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a chamber; a heater power system; and a heater assembly having, an inner core of a first metal, an outer shell of a second metal surrounding said inner core and including a surface for supporting a substrate, and a resistive heating element symmetrically disposed between an upper surface and a lower surface of said outer shell, said first metal having a higher thermal conductivity than said second metal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A heater pedestal for heating a substrate to a temperature of at least about 400°
- C. comprising;
an inner core of a first metal; a shell of a second metal surrounding said first metal, said first metal having a first thermal conductivity greater than a second thermal conductivity of said second metal; a resistive heating element brazed into a groove in said inner core such that said resistive heating element is symmetrical within said inner core and said shell; a stub shaft coupled to a lower portion of said shell; an isolator coupled to said stub shaft with a first cantilever clamp; a support shaft coupled to said isolator with a second cantilever clamp; and a radio-frequency electrode electrically coupled to said inner core, said shell, or said stub shaft. - View Dependent Claims (9, 10)
- C. comprising;
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11. A radio-frequency heater pedestal for heating a substrate to a temperature of at least about 400°
- C. comprising;
a metal heater; a metal heater stub; a first spacer made of the metal sold under the name KOVAR®
, said first spacer welded to said metal heater stub;a ceramic isolator bonded to said first spacer to form a first gas-tight ceramic-to-metal bond; a second spacer made of the metal sold under the name KOVAR®
bonded to said ceramic isolator to form a second gas-tight ceramic-to-metal bond; anda lower support shaft welded to said second spacer, wherein said metal stub, said first spacer, said ceramic isolator, said second spacer, and said lower support shaft define a contiguous volume within the heater pedestal, said contiguous volume containing at least one heater electrode and at least one RF electrode.
- C. comprising;
Specification