Electrostatic Chuck Gas-Hole Structure for Abnormal Discharge Control
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Solution Overview
Problem
Abnormal discharge occurs in electrostatic chucks during plasma etching of wafers, leading to damage of the wafer and the plasma etching apparatus.
Innovation Solution
A substrate fixing device with an electrostatic chuck and a porous body in a gas hole that includes a first recess, a second recess, and a through hole, where the first recess is entirely and the second recess is partly filled with the porous body, controlling the occurrence of abnormal discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If gas holes are provided in the electrostatic chuck for cooling, then wafer cooling performance is improved, but abnormal discharge occurs during plasma etching
Solution Approach 1:
The patent fills the gas holes with porous bodies (such as porous ceramic materials) to modify the gas flow characteristics. The porous structure distributes the gas flow more uniformly and reduces localized electric field concentrations that cause abnormal discharge, while still maintaining effective cooling of the wafer through the electrostatic chuck.
Solution Approach 2:
The patent changes the physical parameters of the gas holes by filling them with porous materials, which alters the gas flow velocity, pressure distribution, and electrical properties. This parameter change allows the system to achieve both effective cooling and suppression of abnormal discharge during plasma etching.
2Object-affected harmful factors
If porous bodies are filled in gas holes, then abnormal discharge is suppressed, but gas flow efficiency may be reduced
Solution Approach 1:
The porous bodies are specifically designed with controlled porosity and pore size distribution to maintain gas flow efficiency. The porous structure provides multiple flow paths that reduce flow resistance while still suppressing abnormal discharge through uniform gas distribution and reduced electric field concentration.
Solution Approach 2:
The patent uses composite porous materials that combine different properties (porosity, thermal conductivity, electrical resistance) to simultaneously achieve abnormal discharge suppression and maintain adequate gas flow efficiency for wafer cooling.
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 described configuration effectively controls abnormal discharge in substrate fixing devices, preventing damage to wafers and plasma etching apparatuses during the etching process.
Implementation Method 1
an electrostatic chuck (30) on a baseplate (10), in which a wafer (W) is attracted
Implementation Method 2
a porous body (60) in a gas hole (33) piercing through a substrate (31) of the electrostatic chuck (30)
Data Source
AI summary
A substrate fixing device includes an electrostatic chuck on a baseplate, and a porous body in a gas hole piercing through a substrate of the electrostatic chuck. The electrostatic chuck attracts an object onto a first surface of the substrate. The gas hole includes a first recess formed in a second surface of the substrate facing the baseplate and depressed toward the first surface, a second recess formed at the bottom of the first recess and depressed toward the first surface, and a through hole extending from the bottom of the second recess to the first surface. The first recess is entirely and the second recess is partly filled with the porous body. A region of the second recess unfilled with the porous body is a recess in the porous body depressed toward the second surface relative to where the bottom of the second recess communicates with the through hole.