Metal-Bond Electrostatic Chuck for Stable Ceramic Resistivity
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Solution Overview
Problem
State-of-the-art electrostatic chucks (ESCs) for plasma processing chambers require multiple high-temperature diffusion bonds, which can alter the resistivity of ceramic materials and increase fabrication costs, while also affecting thermal and electrical properties.
Innovation Solution
The use of a metal bond, such as an aluminum bond, between ceramic components instead of traditional diffusion bonds to reduce the number of high-temperature operations and maintain the as-sintered resistivity of the ceramic materials, thereby simplifying the fabrication process and preserving electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional diffusion bonds are used to join ceramic components, then strong bonding is achieved, but the resistivity of ceramic materials changes and fabrication costs increase
Solution Approach 1:
The patent changes the bonding parameter from high-temperature diffusion bonding to low-temperature metal bonding. Instead of using diffusion bonds that require high temperatures and alter ceramic resistivity, the invention uses metal bonds (such as aluminum or copper) that can be applied at lower temperatures, thereby maintaining the as-sintered resistivity of the ceramic materials while still achieving strong bonding between components.
Solution Approach 2:
The patent introduces a metal layer as an intermediary bonding material between ceramic components. This metal intermediary (aluminum, copper, or other suitable metals) serves as a mediator that joins ceramic parts together without requiring the ceramics to be in direct contact at high temperatures. The metal bond acts as a buffer that preserves the electrical properties of the ceramic materials while providing the necessary mechanical strength.
2Strength
If multiple high-temperature diffusion bonds are used, then component bonding is achieved, but fabrication costs and process complexity increase
Solution Approach 1:
The patent changes the temperature parameter of the bonding process from high-temperature diffusion bonding to low-temperature metal bonding. This parameter change reduces the number of high-temperature operations required, simplifies the fabrication process, and lowers overall manufacturing costs while still achieving strong component bonding through the metal intermediary layer.
3Strength
If high-temperature operations are used for bonding, then strong bonds are formed, but thermal and electrical properties of components are affected
Solution Approach 1:
The patent changes the temperature parameter from high-temperature diffusion bonding to low-temperature metal bonding. This parameter change prevents thermal degradation of the ceramic materials' electrical properties while still achieving adequate bond strength through the metal intermediary. The low-temperature process preserves the as-sintered resistivity and other electrical characteristics of the ceramic components.
Solution Approach 2:
The metal bond serves as a thermal and electrical intermediary that protects the ceramic components from direct high-temperature exposure. The metal layer absorbs the bonding heat and stress, preventing thermal shock and property changes in the ceramic materials, thereby maintaining their electrical reliability.
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 allows for the fabrication of ESCs without resistivity changes, reduces fabrication costs, and maintains the electrical properties of the components, while minimizing the need for high-temperature operations.
Implementation Method 1
bonding the ceramic top plate to the ceramic bottom plate with a metal layer between the ceramic top plate and the ceramic bottom plate
Implementation Method 2
The electrode in the ESC is electrically biased with respect to a substrate disposed on the ESC by an electrical voltage source. Opposing electrostatic charges accumulate in the electrode of the ESC and on the surface of the substrate, the insulative layer precluding flow of charge there between. The electrostatic force resulting from the accumulation of electrostatic charge holds the substrate to the ESC during processing of the substrate.
Implementation Method 3
The ESC may be provided with an embedded electric heater
Data Source
AI summary
Electrostatic chucks (ESCs) for plasma processing chambers, and methods of fabricating ESCs, are described. In an example, a substrate support assembly includes a ceramic bottom plate having heater elements therein. The substrate support assembly also includes a ceramic top plate having an electrode therein. A metal layer is between the ceramic top plate and the ceramic bottom plate. The ceramic top plate is in direct contact with the metal layer, and the metal layer is in direct contact with the ceramic bottom plate.