Electrostatic Chuck Protrusion Pattern for Particle Control
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Solution Overview
Problem
Conventional substrate temperature adjusting-fixing devices with electrostatic chucks face issues with particle attachment to the substrate's opposite surface due to a large contact area between the substrate and the electrostatic chuck's protrusion portions and outer peripheral seal ring, which cannot be effectively mitigated by reducing the diameter of the protrusion portions alone.
Innovation Solution
The electrostatic chuck design features a base body with protrusion portions arranged in a polka-dot pattern on the upper surface, excluding the outer edge, and without an outer peripheral seal ring, allowing for a reduced contact area and improved adsorption force through coulombic force generation, with an inert gas-filled space between the substrate and the base body to enhance heat conductivity and prevent particle attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the contact area between the substrate and the electrostatic chuck is increased to improve adsorption force, then the adsorption force becomes stronger, but particle attachment to the substrate's opposite surface increases
Solution Approach 1:
The base body is segmented into multiple protrusion portions that contact the substrate at discrete locations rather than a continuous large area. This segmentation maintains sufficient adsorption force through multiple contact points while significantly reducing the total contact area, thereby preventing particle attachment to the substrate's opposite surface.
Solution Approach 2:
The electrostatic chuck employs localized contact regions (protrusion portions) rather than uniform contact across the entire substrate surface. This local quality approach concentrates the adsorption function at specific points while leaving most of the substrate surface free from contact, thus eliminating particle attachment issues while maintaining adsorption effectiveness.
2Object-affected harmful factors
If the diameter of protrusion portions is reduced to decrease contact area and prevent particle attachment, then particle attachment is reduced, but the adsorption force becomes insufficient
Solution Approach 1:
Instead of relying on a single large protrusion portion, the system uses multiple smaller protrusion portions distributed across the base body. This segmentation allows each protrusion to be small enough to prevent particle attachment while the collective arrangement of multiple protrusions provides sufficient total adsorption force.
Solution Approach 2:
The solution transitions from considering only the diameter of individual protrusion portions to considering the two-dimensional distribution pattern of multiple protrusions. By arranging protrusions in specific patterns (e.g., polka-dot pattern) across the base body, the system achieves both small individual contact areas and sufficient total contact area for adequate adsorption force.
3Reliability
If an outer peripheral seal ring is added to prevent inert gas leakage, then gas leakage is prevented, but the contact area increases and particle attachment occurs
Solution Approach 1:
The outer peripheral seal ring, which causes particle attachment, is completely removed from the design. Instead, the invention relies on the precise positioning and contact of multiple protrusion portions to maintain vacuum integrity without requiring a continuous seal ring, thus eliminating the particle attachment problem while maintaining reliability.
Solution Approach 2:
The multiple protrusion portions serve as intermediaries that simultaneously provide both the sealing function (preventing inert gas leakage) and the adsorption function. These discrete protrusions replace the continuous seal ring, maintaining vacuum integrity through their arrangement and contact with the substrate while avoiding the particle attachment issue.
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 significantly reduces particle attachment to the substrate's opposite surface while maintaining a strong adsorption force and preventing inert gas leakage, even at lower applied voltages, thus improving the vacuum chamber's integrity and reducing the risk of arcing or charge buildup.
Implementation Method 1
a coulombic force is generated between the adsorption object and the electrostatic electrode by applying a voltage to the electrostatic electrode so as to hold the adsorption object in an adsorption state
Implementation Method 2
an inert gas-filled space between the substrate and the base body to enhance heat conductivity
Data Source
AI summary
There is provided an electrostatic chuck for placing an adsorption object or a base body having an electrostatic electrode embedded therein and generating a coulombic force between the adsorption object and the electrostatic electrode by applying a voltage to the electrostatic electrode so as to hold the adsorption object in an adsorption state, wherein the base body includes a upper surface of the base body opposed to the adsorption object and a protrusion portion provided in the upper surface of the base body so as to come into contact with the adsorption object, and wherein the protrusion portion is provided in a region except for an outer edge portion of the upper surface of the base body, and the outer edge portion is substantially formed in the same plane as that of the upper surface of the base body.