Plasma Substrate Support Structure for Uniform RF Field Delivery
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Solution Overview
Problem
Existing plasma substrate treatment apparatuses face issues with non-uniform electric field generation, increased impedance, and reduced plasma uniformity due to the concentration of electric fields at the connection points of electrodes and power supply rods, leading to decreased substrate treatment efficiency.
Innovation Solution
A substrate support unit is designed with a dielectric plate, a lower electrode, a power supply rod, and a ground member spaced apart by an insulating member, featuring a through-hole in the ground member for the power supply rod and a guide portion to uniformly deliver RF energy, thereby minimizing electric field concentration and impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power supply rod is directly connected to the lower electrode, then RF power can be supplied to generate plasma, but electric field concentration occurs at the connection point leading to non-uniform plasma distribution
Solution Approach 1:
A guide portion is introduced as an intermediary component between the power supply rod and the lower electrode. This guide portion extends upward from the through-hole of the ground member and is spaced apart from the power supply rod, serving as a mediator that directs and distributes the electric field uniformly across the substrate surface, thereby eliminating electric field concentration at the connection point while maintaining effective RF power coupling.
Solution Approach 2:
The guide portion creates a localized controlled electric field distribution pattern. By positioning the guide portion to extend from the through-hole and maintain a specific spacing from the power supply rod, the electric field is locally optimized to achieve uniform distribution across different regions of the lower electrode, ensuring consistent plasma quality throughout the substrate area.
2Device complexity
If the lower electrode and ground member are placed close together, then the apparatus structure is compact, but impedance increases due to mutual electrical influences
Solution Approach 1:
The ground member with its through-hole serves as an intermediary structure that manages the spatial relationship between the power supply rod and the lower electrode. The through-hole allows the power supply rod to pass through while maintaining electrical isolation, enabling the ground member to mediate the electromagnetic interaction and control impedance by providing a reference potential without creating harmful mutual influences.
3Productivity
If high power is fed to the lower electrode, then plasma generation efficiency is improved, but electric field dispersion occurs at the connection area reducing treatment uniformity
Solution Approach 1:
The guide portion modifies the electric field parameter distribution by changing its spatial configuration. Extending the guide portion upward from the through-hole and maintaining a controlled spacing from the power supply rod transforms the concentrated electric field parameter into a uniformly distributed parameter across the substrate surface, enabling high power operation without field dispersion effects.
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 enhances plasma uniformity and substrate treatment efficiency by reducing electric field concentration and impedance, improving etch rate uniformity across substrate regions, and minimizing noise and eddy currents during RF power feeding.
Implementation Method 1
The power supply rod applies RF power to the lower electrode
Implementation Method 2
Plasma is generated by heating a neutral gas to a very high temperature or subjecting the neutral gas to a strong electric field or a radio frequency (RF) electromagnetic field
Implementation Method 3
a lower electrode as a plasma source for exciting a process gas into plasma
Implementation Method 4
A process of treating a substrate, such as a wafer, using plasma is performed by collision of ions and radicals contained in the plasma with the substrate
Data Source
AI summary
The inventive concept relates to a substrate support unit provided in an apparatus for treating a substrate using plasma. In an embodiment, the substrate support unit includes a dielectric plate on which the substrate is placed, a lower electrode that is disposed under the dielectric plate and that has a first diameter, a power supply rod that applies RF power to the lower electrode and has a second diameter, and a ground member disposed under the lower electrode and spaced apart from the lower electrode by a first gap by an insulating member, the ground member including a plate portion having a through-hole formed therein through which the power supply rod passes, in which the through-hole has a third diameter.