Electrostatic Chuck Substrate with Embedded RF Electrodes
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Solution Overview
Problem
Current electrostatic chucks face challenges in efficiently controlling in-plane ion energy density during plasma etching due to the superposition of multiple bias frequencies, leading to variations in wafer processing and adhesive layer deterioration from plasma exposure, which reduces the chuck's lifespan.
Innovation Solution
An electrostatic chuck substrate with a first electrode layer for direct current voltage and multiple independent second electrode layers for different radio frequencies, embedded within an insulating substrate, allowing for precise control of plasma and reducing power loss while protecting the adhesive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thickness of the electrostatic chuck substrate is reduced to minimize power loss, then power loss is reduced, but the adhesive layer becomes more exposed to plasma and deteriorates faster
Solution Approach 1:
The substrate is divided into multiple independent electrode layers (first electrode layer and multiple second electrode layers) embedded within the insulating substrate. This segmentation allows each layer to be independently controlled with different radio frequencies, enabling precise plasma control while maintaining adequate substrate thickness to protect the adhesive layer from plasma exposure.
2Adaptability or versatility
If multiple bias frequencies are superimposed and applied to control plasma, then plasma control capability is improved, but in-plane ion energy density distribution becomes difficult to control
Solution Approach 1:
The electrode structure is segmented into multiple independent second electrode layers that can be controlled independently. Each electrode layer can receive different radio frequency signals, allowing independent control of plasma parameters in different regions, thereby simplifying in-plane distribution control while maintaining versatile plasma control capability.
Solution Approach 2:
Different radio frequencies are applied to different electrode layers to create localized plasma control. This allows different regions of the substrate to have different plasma characteristics tailored to specific processing requirements, improving both plasma control versatility and in-plane distribution control.
3Adaptability or versatility
If radio-frequency waves are applied to control plasma, then plasma control is achieved, but the adhesive layer deteriorates due to plasma exposure
Solution Approach 1:
The insulating substrate acts as an intermediary barrier between the electrode layers and the plasma environment. By embedding the electrode layers within the insulating substrate rather than exposing them directly to plasma, the adhesive layer is protected from plasma deterioration while still allowing effective plasma control through the electrode structure.
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 configuration enables flexible control of ion energy density and extends the electrostatic chuck's lifespan by minimizing adhesive layer exposure to plasma and reducing power requirements.
Implementation Method 1
radio-frequency waves for plasma generation
Implementation Method 2
DC voltage for attraction
Implementation Method 3
radio-frequency waves for plasma control
Implementation Method 4
the thicker the substrate 3, the more power loss occurs
Implementation Method 5
the density of in-plane ion energy generated by the application of the radio-frequency waves is automatically determined by such an influence as the skin effect
Data Source
AI summary
An electrostatic chuck includes a metal base member and an insulating substrate having an opposite surface to an attraction surface joined onto the base member via an adhesive layer. In the substrate, an electrode layer to which a direct current voltage for attraction is applied is embedded in a portion of the substrate, close to the attraction surface. In addition, a plurality of independent RF electrode layers to which different radio frequencies for plasma control are fed, respectively, are embedded in portions of the substrate, at an opposite side of the first electrode layer to the attraction surface. The RF electrode layers are arranged separately in different layers which are not on an identical plane in such a manner as to partially overlap each other in a plan view.