Porous Electrostatic Chuck Structure for Arc Discharge Suppression
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Solution Overview
Problem
Existing electrostatic chucks face challenges in suppressing arc discharge during substrate processing, particularly in devices like CVD, sputtering, and ion implantation, where inert gases are used for temperature control, as the gas feed channels and through holes can act as discharge paths.
Innovation Solution
The electrostatic chuck design incorporates a ceramic dielectric substrate with a first porous part positioned between the base plate and the substrate, featuring a compact section and a porous section with specific pore configurations to extend the current conduction path, thereby reducing electron acceleration and arc discharge occurrence while maintaining gas flow efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous part is provided in the gas feed channel to improve resistance to arc discharge, then arc discharge suppression is enhanced, but the gas flow efficiency may be reduced
Solution Approach 1:
The porous part is provided only at the specific location where the gas feed channel passes through the ceramic dielectric substrate, rather than throughout the entire channel. This localized porosity provides arc discharge suppression at the critical interface while maintaining smooth gas flow in the main channel, thus resolving the contradiction between reliability and productivity.
Solution Approach 2:
A porous part with controlled pore structure is introduced at the channel-substrate interface. The porous structure increases the effective path length for electrical discharge while maintaining adequate gas flow, as the pores are designed to allow gas passage while blocking electron acceleration paths that lead to arc discharge.
2Temperature
If a through hole is provided in the ceramic dielectric substrate for gas feeding, then temperature control is enabled, but the through hole may constitute a path of discharge
Solution Approach 1:
The porous part is localized at the region where the gas feed channel intersects with the ceramic dielectric substrate. This localized treatment provides discharge resistance at the critical interface while maintaining the through-hole functionality for gas flow and temperature control, thus resolving the contradiction between temperature control capability and arc discharge resistance.
3Temperature
If the gas feed channel and through hole are provided to enable inert gas flow for temperature control, then substrate temperature management is improved, but arc discharge may occur along these pathways
Solution Approach 1:
The porous part is strategically positioned at the interface between the gas feed channel and the ceramic dielectric substrate, providing arc discharge suppression at the most vulnerable location while maintaining unobstructed gas flow through the channel for effective temperature management.
Solution Approach 2:
The porous part acts as an intermediary structure at the channel-substrate interface, mediating between the need for gas flow (temperature control) and the need to prevent discharge. The porous structure allows gas molecules to pass while presenting a tortuous path that suppresses electron acceleration and arc formation.
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 design effectively suppresses arc discharge occurrences while ensuring smooth gas flow and maintaining the electrostatic chuck's operational efficiency, enhancing the reliability and performance of substrate processing devices.
Implementation Method 1
electric discharge (arc discharge) may occur from the plasma in the device toward the metallic base plate. The gas feed channel of the base plate and the through hole of the ceramic dielectric substrate may be likely to constitute a path of discharge
Implementation Method 2
the first compact section is configured to overlap the first hole part, and the porous section is configured not to overlap the first hole part
Implementation Method 3
Electric power for electrostatic suction is applied to the incorporated electrode. Thus, the electrostatic chuck sucks a substrate such as a silicon wafer by electrostatic force
Implementation Method 4
an inert gas such as helium (He) is passed between the front surface of the ceramic dielectric substrate and the back surface of the suction target substrate to control the temperature of the suction target substrate
Implementation Method 5
the temperature increase of the substrate is suppressed
Data Source
AI summary
An electrostatic chuck includes a ceramic dielectric substrate, a base plate, and a first porous part. The ceramic dielectric substrate has a first major surface and a second major surface. The base plate supports the ceramic dielectric substrate and includes a gas feed channel. The first porous part is provided between the base plate and the first major surface. The ceramic dielectric substrate includes a first hole part. The first porous part includes a porous section, and a first compact section being more compact than the porous section. The porous section including a plurality of sparse portions including a plurality of pores including a first pore and a second pore, and a dense portion having a higher density than the sparse portion.