Coulombic Electrostatic Chuck for Large Substrate Holding
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Solution Overview
Problem
Existing electrostatic chucks face challenges in uniformly supporting larger, more massive substrates in high-temperature and corrosive processing environments, often resulting in substrate damage and inadequate force application, particularly in the display industry where larger displays are being produced.
Innovation Solution
A Coulombic electrostatic chuck design featuring a substrate with a conductive layer, an arc elimination layer, and a high-k dielectric layer with a dielectric constant of at least 10 and resistivity of 10^11 Ohm-cm, which provides improved force distribution and durability for larger workpieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If vacuum chucks are used to hold wafers, then the force applied is more uniform than mechanical chucks, but sufficient force cannot always be applied in low pressure chambers
Solution Approach 1:
The patent replaces the mechanical vacuum chuck system with an electrostatic chuck system that uses electrostatic forces to hold substrates. The electrostatic chuck includes a chucking surface with embedded electrodes that generate electrostatic attraction forces, substituting the vacuum-based mechanical holding mechanism with an electric field-based mechanism that provides both uniform distribution and sufficient magnitude of holding force.
Solution Approach 2:
The patent changes the physical parameter of force generation from pressure differential (vacuum) to electrostatic force (electric field). By applying high voltage to the embedded electrodes, the system generates strong electrostatic attraction forces that can hold substrates firmly while maintaining uniform distribution across the substrate surface, overcoming the limitations of vacuum chucks in low pressure environments.
2Stability of the object's composition
If electrostatic chucks are used to hold workpieces, then a more uniform force is applied, but improved flexibility and adaptability for larger substrates are needed
Solution Approach 1:
The patent divides the chucking surface into multiple segments with independently controllable electrodes. This segmentation allows different regions of the chuck to be controlled independently, enabling adaptation to substrates of various sizes and shapes. The segmented electrode structure can be selectively activated to match the substrate footprint, providing both uniform force distribution and flexibility for different substrate dimensions.
Solution Approach 2:
The patent implements dynamic control of the electrostatic chuck by allowing independent voltage control of multiple electrode segments. This dynamic capability enables the system to adapt to different substrate sizes, shapes, and processing requirements by selectively activating appropriate electrode regions and adjusting voltage levels, providing versatility while maintaining uniform force distribution.
3Area of moving object
If larger, more massive substrates are processed, then display size increases, but substrate damage and inadequate force application occur
Solution Approach 1:
The patent replaces mechanical holding methods with electrostatic attraction for larger substrates. The electrostatic chucking surface generates distributed electrostatic forces across the entire substrate surface, providing reliable holding for large, massive substrates without the point-contact stresses of mechanical clamps that could cause damage or inadequate holding.
Solution Approach 2:
The patent employs a composite chucking surface structure combining conductive materials (for electrode formation), dielectric materials (for insulation and charge storage), and potentially resistive layers (for charge distribution control). This composite material system enables effective electrostatic holding of large substrates by distributing forces uniformly while preventing charge accumulation that could lead to substrate damage.
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 design enhances the chucking performance by maintaining larger workpieces in proximity, reducing the risk of damage and improving operational reliability in high-temperature and corrosive environments, suitable for processing larger displays.
Implementation Method 1
ESCs utilizing a Coulombic effect rely upon the embedded electrode as essentially one plate of a capacitor and the workpiece as the second plate of a capacitor, and a dielectric material between the plates. When a voltage is applied across the workpiece and the electrode, the workpiece is attracted to the surface of the chuck.
Implementation Method 2
Electrostatic chucks work by utilizing a voltage difference between the workpiece and electrodes that can be embedded in the body of the electrostatic chuck
Implementation Method 3
Chucks using a JR effect use a resistive layer between the electrode and the workpiece, particularly in workpieces that are semiconductive or conductive. The resistive layer has a particular resistivity, typically less than about 10^10 Ohm-cm, to allow charges within the resistive layer to migrate during operation. That is, during operation of a JR effect ESC, charges within the resistive layer migrate to the surface of the chuck and charges from the workpiece migrate toward the bottom surface thereby generating the necessary attractive electrostatic force.
Data Source
AI summary
A Coulombic electrostatic chuck is disclosed which includes a substrate, a conductive layer overlying the substrate, and an arc elimination layer overlying the conductive layer. The electrostatic chuck further includes a high-k dielectric layer overlying the arc elimination layer, wherein the high-k dielectric layer has a dielectric constant of not less than about 10 and a resistivity of not less than about 1011 Ohm-cm.