Electrostatic Chuck Porous Structure for Plasma-Resistant Gas Flow
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Solution Overview
Problem
Conventional electrostatic chucks face a trade-off between gas permeability and plasma resistance in their porous bodies, leading to issues like abnormal discharge during plasma processes.
Innovation Solution
A holding device with a dual porous body structure, where the first porous body in the gas flow passage has higher plasma resistance and purity than the second porous body, both made of ceramic materials, ensuring effective gas permeability and plasma resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the gas permeability of the porous body is improved, then the gas flow rate increases, but the plasma resistance decreases
Solution Approach 1:
The gas flow passage is divided into multiple segments, each containing a porous body. By segmenting the passage into multiple sections with different porous body configurations, the system achieves both high gas flow rate and high plasma resistance through cumulative effect of multiple barriers.
Solution Approach 2:
Different regions of the gas flow passage are assigned different porous body properties. Specifically, porous bodies with different pore sizes, materials, or densities are placed in different locations to optimize local gas permeability while maintaining overall plasma resistance.
2Reliability
If the plasma resistance of the porous body is improved, then abnormal discharge is suppressed, but the gas permeability decreases
Solution Approach 1:
The gas flow passage is divided into multiple segments, each containing a porous body. By segmenting the passage into multiple sections with different porous body configurations, the system achieves both high gas flow rate and high plasma resistance through cumulative effect of multiple barriers.
Solution Approach 2:
The porous body is constructed using composite material structures, combining materials with different properties to achieve both high plasma resistance and adequate gas permeability. The composite structure allows optimization of electrical properties while maintaining gas flow characteristics.
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 porous body design effectively suppresses abnormal discharge while maintaining high gas permeability, enhancing the reliability of the electrostatic chuck in plasma processes.
Implementation Method 1
a gas permeable first porous body disposed in the first gas flow passage and containing a ceramic material as a main component... a gas permeable second porous body disposed in the second gas flow passage
Implementation Method 2
a wafer is held on a surface of the holding substrate by electrostatic attraction. Electrostatic attraction is generated when a voltage is applied to chuck electrodes provided in the holding substrate
Implementation Method 3
a heat conduction gas (inert gas) such as helium gas is supplied between the holding substrate and a wafer, thereby removing heat from the wafer
Data Source
AI summary
A holding device includes: a holding substrate which includes a first surface and an opposed second surface, a first gas flow passage formed therein and having a first gas outlet open to the first surface and a first gas inlet which is open to the second surface, and a gas permeable first porous body disposed in the first gas flow passage and containing a ceramic material as a main component; and a base which includes a third surface opposed to the second surface and an opposed fourth surface, a second gas flow passage formed therein and having a second gas outlet open to the third surface, and a gas permeable second porous body disposed in the second gas flow passage and containing a ceramic material as a main component. A plasma resistance of the first porous body is higher than a plasma resistance of the second porous body.