Electrostatic Chuck Bond Seal for Plasma Erosion Containment
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Solution Overview
Problem
Substrate processing systems face challenges in protecting the bond layer of substrate supports from erosion due to plasma exposure, leading to contamination and inefficiencies in thermal transport, as existing solutions either compromise on wear resistance or seal effectiveness.
Innovation Solution
A dual-layer protective seal is implemented, comprising a flexible, inner silicone layer for a hermetic seal and a removable, plasma-resistant outer Teflon O-ring, which minimizes exposure to reactive species and allows for easy replacement, maintaining thermal uniformity and reducing contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer seal is used around the bond layer, then the structure is simple and easy to manufacture, but the seal effectiveness and wear resistance are compromised
Solution Approach 1:
The seal is divided into two distinct layers: an inner seal layer directly adjacent to the bond layer and an outer seal layer surrounding the inner layer. This segmentation allows each layer to be optimized for different functions - the inner layer provides hermetic sealing while the outer layer provides plasma resistance and structural support, thereby improving overall seal effectiveness without requiring excessive complexity in a single component
Solution Approach 2:
The dual-layer seal structure combines materials with different properties - the inner layer uses a first material optimized for sealing against the bond layer, while the outer layer uses a second material optimized for plasma resistance. This composite approach allows the seal system to simultaneously achieve hermetic sealing and wear resistance, resolving the contradiction between reliability and manufacturing simplicity
2Reliability
If the outer seal layer is made plasma-resistant, then erosion protection is improved, but the flexibility and seal effectiveness may be reduced
Solution Approach 1:
By separating the seal into two layers, the patent allows the outer layer to be made from plasma-resistant material for erosion protection, while the inner layer can be made from a more flexible material that maintains effective sealing against the bond layer. This segmentation resolves the contradiction by assigning different functional requirements to different layers rather than requiring a single material to satisfy both conflicting demands
3Reliability
If the bond layer is directly exposed to plasma, then the structure is simpler, but contamination and erosion increase
Solution Approach 1:
The dual-layer seal structure creates a protective barrier between the plasma environment and the bond layer. The inner layer provides direct protection against plasma exposure, preventing contamination and erosion of the bond layer, while the outer layer provides additional structural support and plasma resistance. This segmented approach protects the bond layer without requiring complete redesign of the entire substrate support structure
Solution Approach 2:
The dual-layer seal acts as an intermediary barrier between the plasma environment and the bond layer. This intermediate structure protects the bond layer from direct plasma exposure and contamination while maintaining the overall structural integrity and thermal transport pathways, thereby improving contamination resistance without excessive structural complexity
4Reliability
If a thick seal layer is used to improve sealing, then seal effectiveness is improved, but thermal transport from ceramic layer to baseplate is reduced
Solution Approach 1:
By dividing the seal into two layers, the patent can optimize each layer's thickness for its specific function. The inner layer can be made thin to minimize thermal resistance while still providing effective sealing against the bond layer. The outer layer can be made thicker to provide structural support and plasma resistance. This segmentation allows the overall seal to be effective while maintaining good thermal transport through the ceramic layer to baseplate pathway
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 dual-layer seal effectively protects the bond layer from plasma erosion, reduces contamination risks, and extends the lifespan of the outer layer while maintaining seal effectiveness, thereby enhancing the reliability and efficiency of substrate processing systems.
Implementation Method 1
The inner layer is between the outer layer and the bond layer... The inner layer comprises a first material and the outer layer comprises a second material
Implementation Method 2
A removable, plasma-resistant outer Teflon O-ring, which minimizes exposure to reactive species
Implementation Method 3
The overall thermal transfer coefficient of the bond is selected to optimize thermal transport from the ceramic layer to the baseplate via the bond and filler
Implementation Method 4
A substrate may be arranged on a substrate support, such as a pedestal, an electrostatic chuck (ESC)... The wafer may be clamped to the ceramic layer during processing
Data Source
AI summary
A substrate support for a substrate processing chamber includes a baseplate, a ceramic layer bonded to the baseplate, and a seal provided in an outer perimeter of an interface between the ceramic layer and the baseplate. The seal is arranged to seal the interface from the substrate processing chamber and includes an adhesive comprising a first material arranged in the outer perimeter of the interface between the ceramic layer and the baseplate and a ring arranged in the outer perimeter of the interface between the ceramic layer and the baseplate. The ring is removable and comprises a second material having a greater resistance to plasma erosion than the first material.