Electrostatic Chuck Porous Structure Arc Discharge
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Solution Overview
Problem
Existing electrostatic chucks face challenges in reducing arc discharge during substrate processing in devices like CVD, sputtering, and ion implantation, where inert gases are used to control substrate temperature, as the gas feed channels and through holes can act as discharge paths, leading to electric discharge issues.
Innovation Solution
The electrostatic chuck incorporates a porous structure with a combination of sparse and dense regions in the ceramic dielectric substrate and base plate, designed to elongate the conduction path for current flow, reducing electron acceleration and enhancing mechanical strength, thereby suppressing arc discharge while maintaining gas flow efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a gas feed channel and through hole are provided in the ceramic dielectric substrate to feed inert gas for temperature control, then substrate temperature control is improved, but arc discharge occurs along the gas feed path
Solution Approach 1:
The patent applies porous materials by providing a porous part in the gas feed channel of the base plate and in the through hole of the ceramic dielectric substrate. The porous structure increases the path length for electron movement and reduces electron acceleration, thereby suppressing arc discharge while maintaining gas flow for temperature control.
Solution Approach 2:
The porous part acts as an intermediary element between the gas feed channel and the through hole. It mediates the gas flow while simultaneously providing discharge prevention functionality, converting the direct gas path into a tortuous path that prevents arc discharge.
2Reliability
If a porous part is provided in the gas feed channel and through hole to prevent arc discharge, then resistance to arc discharge is improved, but gas flow rate may be reduced
Solution Approach 1:
The patent applies local quality by providing the porous part only in specific locations where arc discharge is likely to occur (in the gas feed channel and through hole), while maintaining other parts of the system with normal properties. This localized approach prevents arc discharge without significantly affecting overall gas flow rate.
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 porous structure effectively reduces arc discharge occurrences while improving the mechanical strength and gas flow rate, ensuring reliable substrate temperature control and processing stability.
Implementation Method 1
designed to elongate the conduction path for current flow, reducing electron acceleration
Implementation Method 2
suppressing arc discharge while maintaining gas flow efficiency
Implementation Method 3
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
Data Source
AI summary
According to one embodiment, an electrostatic chuck includes a ceramic dielectric substrate, a base plate, and a first porous part. The ceramic dielectric substrate includes first and second major surfaces, and at least one groove. The second major surface is opposite to the first major surface. The base plate supports the ceramic dielectric substrate and includes a gas feed channel. The first porous part is provided between the groove and the gas feed channel. The ceramic dielectric substrate includes holes communicating with the groove and the gas feed channel and piercing the ceramic dielectric substrate in a first direction from the base plate toward the ceramic dielectric substrate. The first porous part includes at least one porous region including pores, and at least one dense region denser than the porous region. The porous region further includes at least one dense part.