Electrostatic Chuck Cooling Structure for Stable Wafer Temperature
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Solution Overview
Problem
Conventional substrate support systems in semiconductor processing face challenges in maintaining stable temperature control due to excess heat generation from plasma processes, leading to thermal shifts and non-uniform film deposition.
Innovation Solution
Incorporation of active and passive cooling features into the pedestal, combined with a heater, to dissipate excess heat and maintain a stable temperature, using a substrate support assembly with a dielectric coating and insulating materials to prevent shorting and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If internal heating devices are used to generate heat within the substrate support, then substrate temperature control is improved, but heat loss and thermal instability increase
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the heating element and the substrate support. This dielectric layer has low thermal conductivity that acts as a thermal barrier, preventing direct heat conduction to the support structure and reducing parasitic heat loss while still allowing the heating element to effectively control substrate temperature
Solution Approach 2:
The substrate support incorporates a porous structure with controlled porosity. The porous material provides thermal insulation through trapped air pockets while maintaining mechanical strength and electrical conductivity, thereby reducing heat loss to the support structure and improving thermal stability
2Adaptability or versatility
If the substrate support is used for both heat generation and plasma generation, then device functionality is improved, but interference effects and temperature stability deteriorate
Solution Approach 1:
The substrate support structure is segmented into functionally distinct regions: a heating element region for thermal control, a dielectric layer for electrical isolation, and a plasma generation region. This spatial segmentation allows independent optimization of each function while minimizing interference between heating and plasma generation processes
Solution Approach 2:
A dielectric layer serves as an intermediary between the heating element and the plasma generation zone. This dielectric barrier prevents direct electrical discharge between the heating element and substrate while allowing thermal energy to pass through, thereby enabling simultaneous heating and plasma generation without interference
3Device complexity
If conventional substrate support systems are used during plasma-enhanced deposition, then device simplicity is maintained, but thermal shifts and film uniformity worsen
Solution Approach 1:
The substrate support employs local quality variations through a layered structure with different material properties at different depths. The heating element region has high thermal conductivity for efficient heating, while the dielectric layer has low thermal conductivity for thermal isolation. This local differentiation enables precise temperature control and reduces thermal shifts that would otherwise cause film uniformity problems
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
The solution provides stable temperature control, reducing thermal shifts and ensuring uniform film deposition by effectively managing heat dissipation and plasma generation, enhancing the quality of semiconductor processing.
Implementation Method 1
The substrate support assemblies may include a cooling hub positioned below a base of the support stem and coupled with a cooling fluid source. The electrostatic chuck body may define at least one cooling channel that is in communication with a cooling fluid source.
Implementation Method 2
The substrate support assemblies may include a heater embedded within the electrostatic chuck body.
Implementation Method 3
The substrate support assemblies may include an RF rod extending through the support stem and electrically coupled with the electrostatic chuck body.
Data Source
AI summary
Exemplary substrate support assemblies may include an electrostatic chuck body defining a support surface that defines a substrate seat. The substrate support surface may include a dielectric coating. The substrate support assemblies may include a support stem coupled with the electrostatic chuck body. The substrate support assemblies may include a cooling hub positioned below a base of the support stem and coupled with a cooling fluid source. The electrostatic chuck body may define at least one cooling channel that is in communication with a cooling fluid source. The substrate support assemblies may include a heater embedded within the electrostatic chuck body. The substrate support assemblies may include an AC power rod extending through the support stem and electrically coupled with the heater. The substrate support assemblies may include a plurality of voids formed within the electrostatic chuck body between the at least one cooling channel and the heater.