Electrostatic Chuck Porous Gas Path for Long-Term Arcing Resistance
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Solution Overview
Problem
Electrostatic chucks used in processing apparatuses face challenges in maintaining long-term suppression of arcing due to electrical discharge, particularly in the gas inlet paths and through-holes of ceramic dielectric substrates, which can lead to corrosion and reduced arcing resistance over time.
Innovation Solution
The electrostatic chuck design incorporates a ceramic porous part with a dense portion and a porous portion, where the dense portion covers the outer circumference of the porous portion and includes protruding parts to form a physical barrier, enhancing arcing resistance and preventing particle penetration, thereby maintaining effective arcing suppression over a longer period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a through-hole is provided in the ceramic dielectric substrate for gas flow, then temperature control of the substrate is improved, but the gas inlet path becomes a path for electrical discharge (arcing)
Solution Approach 1:
The patent employs a porous plug made of porous ceramic material positioned in the through-hole of the ceramic dielectric substrate. This porous structure allows inert gas to flow through while simultaneously increasing the breakdown voltage and suppressing electrical discharge. The porous material acts as both a flow path and an insulating barrier, resolving the contradiction between temperature control requirements and arcing prevention.
Solution Approach 2:
The porous plug serves as an intermediary element between the gas inlet path and the through-hole in the ceramic dielectric substrate. It mediates the conflicting requirements by allowing gas passage while blocking electrical discharge paths, thus protecting the bonding part and maintaining system reliability without compromising temperature control.
2Reliability
If the gas inlet path is made porous to suppress arcing, then arcing resistance is improved, but particles may penetrate into the path causing corrosion
Solution Approach 1:
The patent uses a porous plug with controlled porosity to suppress arcing while preventing particle penetration. The porous structure increases breakdown voltage and suppresses electrical discharge, yet the specific pore size and distribution are designed to block particles from entering the gas inlet path, thereby preventing corrosion of the bonding part.
Solution Approach 2:
The porous plug is made of porous ceramic material that combines insulating properties with particle filtration capabilities. This composite material approach allows the single component to simultaneously address multiple issues: arcing suppression through high breakdown voltage and particle prevention through appropriate pore structure.
3Reliability
If a porous part is located in the gas inlet path to suppress arcing, then breakdown voltage is improved, but the bonding part may still be exposed to plasma corrosion
Solution Approach 1:
The porous plug acts as an intermediary barrier between the plasma environment and the bonding part. It suppresses arcing and prevents particle penetration, thereby protecting the bonding part from plasma corrosion while maintaining the electrical insulation and gas flow functions required for reliable operation.
Solution Approach 2:
The porous ceramic plug provides both electrical insulation to increase breakdown voltage and physical filtration to prevent particle penetration. This dual function protects the bonding part from plasma corrosion while maintaining the necessary electrical and flow properties of the gas inlet path.
4Reliability
If the gas inlet path is sealed to prevent particle penetration, then corrosion is suppressed, but gas flow is blocked
Solution Approach 1:
The porous plug provides a controlled flow path through its porous structure. It allows inert gas to pass through while simultaneously blocking particle penetration and suppressing arcing. This resolves the contradiction between maintaining gas flow for productivity and preventing particle penetration for corrosion resistance.
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 enhanced design effectively increases arcing resistance and maintains the suppression effect for a longer duration by preventing particle penetration and ensuring reliable gas flow, thus improving the operational stability of the electrostatic chuck.
Implementation Method 1
a ceramic porous part that is located in the counterbore part and includes an exposed surface exposed in the third hole part... the ceramic porous part includes a porous portion that is gas-permeable and a dense portion that is denser than the porous portion
Implementation Method 2
the porous portion is gas-permeable
Implementation Method 3
the dense portion covers an outer circumference of the porous portion... at least a part of the dense portion includes a first protruding part protruding toward the third hole part along the first direction from the exposed surface
Implementation Method 4
An electrostatic chuck that includes an electrode and a ceramic dielectric substrate of alumina or the like clamps a substrate such as a silicon wafer or the like by an electrostatic force by applying electrical power for electrostatic clamping to the electrode
Implementation Method 5
the temperature of the substrate that is the clamping object is controlled by causing an inert gas such as helium (He) or the like to flow between the front surface of the ceramic dielectric substrate and the back surface of the substrate that is the clamping object
Implementation Method 6
causing an inert gas such as He or the like to contact the substrate by causing the inert gas to flow between the ceramic dielectric substrate and the substrate that is the clamping object
Data Source
AI summary
An electrostatic chuck includes a ceramic dielectric substrate, a base plate, a bonding part, a gas inlet path, a counterbore part, and a ceramic porous part. The bonding part is located between the ceramic dielectric substrate and the base plate. The gas inlet path extends through the ceramic dielectric substrate, the base plate, and the bonding part. The gas inlet path includes a first hole part, a second hole part, and a third hole part. The first hole part is positioned at the ceramic dielectric substrate. The second hole part is positioned at the base plate. The third hole part is positioned at the bonding part. The counterbore part is located in at least one of the first hole part or the second hole part. The ceramic porous part is located in the counterbore part. The ceramic porous part includes an exposed surface exposed in the third hole part.