Electrostatic Chuck Radial Feature Distribution and Seasoning Layer
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Solution Overview
Problem
Conventional electrostatic chucks fail to adequately support highly bowed semiconductor substrates during processing, leading to defocus issues and damage from repetitive chucking due to insufficient chucking force and wear of substrate supporting features.
Innovation Solution
A substrate support with a ceramic body, embedded RF electrode, and a plurality of substrate supporting features, where the number increases radially from the center to the edge, and a seasoning layer of silicon nitride or silicon oxide is applied to reduce wear and enhance chucking force, minimizing damage to the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrostatic chucks are used to hold substrates, then the substrate can be supported during processing, but the substrate supporting features wear due to repetitive chucking causing damage to backside layers
Solution Approach 1:
A seasoning layer is introduced as an intermediary between the substrate supporting features and the substrate backside. This seasoning layer absorbs the wear and damage during repetitive chucking operations, protecting the underlying substrate layers from damage while maintaining reliable substrate support.
Solution Approach 2:
The seasoning layer acts as a sacrificial, consumable component that is intentionally designed to wear away over time. This disposable layer protects the more critical substrate layers by taking on the damage from repetitive mechanical contact during chucking operations.
2Force
If high chucking voltages are used to increase chucking force for bowed substrates, then the electrostatic chuck can hold the substrate, but arcing occurs during processing
Solution Approach 1:
The patent changes the physical parameters of the substrate support system by introducing substrate supporting features that increase the effective contact area and distribute the chucking force. This allows achieving the required holding force for bowed substrates through increased surface area rather than increasing voltage, thereby preventing arcing.
3Object-affected harmful factors
If the number of substrate supporting features is increased to distribute force evenly, then backside damage is reduced, but device complexity increases
Solution Approach 1:
The substrate support surface is segmented into multiple discrete substrate supporting features distributed across the chucking surface. This segmentation distributes the mechanical contact points to reduce localized stress and damage to the substrate backside layers, while the modular nature of the features keeps the overall design manageable.
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 effectively increases the chucking force and reduces substrate warpage, minimizing damage to the backside layers and improving CD uniformity by distributing the force evenly across a greater number of supporting features, thus addressing the limitations of conventional electrostatic chucks.
Implementation Method 1
An RF electrode is disposed within the ceramic body
Implementation Method 2
the backside of a substrate, such as a semiconductor wafer, is held to the face of the electrostatic chuck by an electrostatic force that is provided from one or more electrodes embedded in the surface of the electrostatic chuck
Data Source
AI summary
The present disclosure generally relates to substrate supports for semiconductor processing. In one embodiment, a substrate support is provided. The substrate support includes a body comprising a substrate chucking surface, an electrode disposed within the body, a plurality of substrate supporting features formed on the substrate chucking surface, wherein the number of substrate supporting features increases radially from a center of the substrate chucking surface to an edge of the substrate chucking surface, and a seasoning layer formed on the plurality of the substrate supporting features, the seasoning layer comprising a silicon nitride.