Electrostatic Chuck Heater Copper Wire Thermal Uniformity
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Solution Overview
Problem
Conventional electrostatic chuck heaters with high-resistance heating members suffer from excessive temperature increase when densely routed, leading to impaired thermal uniformity due to increased temperature differences between heated and unheated areas.
Innovation Solution
The use of copper wires embedded in a resin sheet, routed densely across multiple zones with low electrical resistance, reduces excessive temperature increases and allows for closer spacing, improving thermal uniformity by minimizing temperature differences across the wafer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high-resistance heating members (titanium, tungsten, molybdenum) are densely routed, then heating efficiency is improved, but temperature increases excessively causing thermal non-uniformity
Solution Approach 1:
The patent changes the electrical resistance parameter of the heating member from high-resistance materials (titanium, tungsten, molybdenum) to low-resistance copper material. This parameter change allows the heating member to be densely routed without excessive temperature increase, as copper's low resistance reduces I²R heating losses and enables better heat distribution across the wafer surface.
2Temperature
If routing spacing of heating member is increased to prevent excessive temperature, then thermal uniformity is improved, but temperature difference between heated and unheated areas increases
Solution Approach 1:
By changing the material parameter from high-resistance to low-resistance copper, the patent enables smaller routing spacing without causing excessive temperature increase. The low resistance of copper allows current to flow efficiently through densely packed traces, maintaining uniform heat distribution across the entire wafer surface rather than creating hot spots in sparsely routed areas.
3Productivity
If copper wires are used with low electrical resistance, then routing density can be increased, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes copper's inherently low electrical resistance parameter to enable high routing density. While this does require precise manufacturing to maintain trace integrity at small dimensions, the low resistance特性 of copper provides a margin of error that allows practical implementation of dense routing patterns that would be impossible with high-resistance materials.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances thermal uniformity by allowing for a higher density of copper wires and thinner resin sheets, reducing thermal resistance and maintaining low electrical resistance, thus achieving precise temperature control across the wafer surface.
Implementation Method 1
the heater wires are provided one for each of many zones of the resin sheet, and each of the heater wires is composed of copper wire routed unicursally from one end to the other end so as to extend throughout the zone. Copper has a low electrical resistance compared to titanium, tungsten, molybdenum, and so forth. Therefore, even if the heater wires are densely routed, the temperature does not increase excessively
Implementation Method 2
the resin sheet functions as a buffer layer that reduces rapid expansion or contraction of the electrostatic chuck
Implementation Method 3
the thickness of the heater wires may be set to 35 μm or less. By doing so, the resin sheet can be made thin, and therefore the thermal resistance between the electrostatic chuck and the support pedestal can be reduced
Data Source
AI summary
An electrostatic chuck heater is such that a sheet heater formed by embedding a heater wire in a resin sheet is disposed between an electrostatic chuck and a support pedestal. The heater wires are provided one for each of many zones of the resin sheet, and are composed of copper wires routed unicursally from their first ends to their second ends so as to extend throughout the zones.