Electrostatic Chuck Arc Prevention via Insulating Gas Path
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Solution Overview
Problem
Electrostatic chucks face challenges in preventing arcing when used with high-density plasma, leading to wafer damage and reduced cooling efficiency due to the non-uniformity of plasma etching and the distance between the cooling device and the wafer mounting surface.
Innovation Solution
Incorporation of an arc prevention member made of an insulating material within the electrostatic chuck, which creates a gas path to communicate with the gas supply port, reducing the likelihood of arcing by managing gas flow and plasma density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thickness of the electrostatic chuck is reduced to improve cooling efficiency, then cooling efficiency is improved, but arcing occurs near the pores
Solution Approach 1:
An insulating member is introduced as an intermediary substance between the cooling device and the electrostatic chuck body. This insulating member fills the counter bore and extends into the pore, creating a physical barrier that prevents direct contact between the RF electrode and the chuck body, thereby eliminating the arcing path while maintaining the thin-chuck design for efficient cooling
Solution Approach 2:
The dielectric constant and electrical conductivity parameters are modified by introducing the insulating member with different electrical properties. This changes the electrical field distribution and prevents breakdown arcing, allowing the chuck thickness to be reduced without causing arcing issues
2Manufacturing precision
If plasma density is increased to solve on-uniformity in plasma etching, then etching uniformity is improved, but heat flow into the wafer increases requiring thinner chuck design
Solution Approach 1:
The chuck body is segmented into functional zones with the insulating member strategically positioned in the pore region. This segmentation allows the bulk chuck material to provide thermal management while the localized insulating structure enables high plasma density operation by preventing arcing at the critical pore location
3Temperature
If the distance between cooling device and wafer mounting surface is reduced to improve cooling, then cooling efficiency is improved, but arcing occurs near gas supply ports
Solution Approach 1:
The insulating member acts as a mediator that extends from the counter bore into the pore, creating an insulating barrier around the gas supply port region. This allows the cooling device to be positioned close to the wafer mounting surface for efficient heat removal while the insulating member prevents arcing from occurring near the gas supply ports
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 solution effectively prevents arcing, enhances plasma density, and improves cooling efficiency, allowing for increased wafer processing speed during plasma etching without damaging the chuck or the wafer.
Implementation Method 1
the electrostatic chuck can be used for efficiently removing heat created in the process from the wafer so as to maintain the temperature of the wafer substantially constant
Implementation Method 2
An electrostatic chuck is used as a mounting base for fixing (holding) a workpiece
Implementation Method 3
a pore (passage) has been provided in the electrostatic chuck for a back side gas, such as Helium (He), to flow therethough to the back side of the wafer
Data Source
AI summary
An electrostatic chuck includes (a) a cooling device serving as an RF electrode, including a gas supply port penetrating through the cooling device, the gas supply port extending from one main surface to the other main surface, and a main counter bore portion having a diameter larger than that of the gas supply port, the main counter bore portion provided in an opening of the gas supply port; (b) an arc prevention member buried in the main counter bore portion and made of an insulating member, wherein a gas path is provided, the gas path is configured to communicate with the gas supply port; and (c) an electrostatic chuck body arranged on the cooling device, defining a work mounting surface on a top surface of the electrostatic chuck body, provided with a pore in communication with the gas supply port via the gas path.