Plasma Wafer Stage Resonant Ring Electrode for Uniform Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional plasma processing techniques face limitations in uniformly distributing high-frequency power to the conductor ring on the outer peripheral side of a wafer, leading to variations in etching characteristics and reduced processing yield due to issues like wear and insulator interference.
Innovation Solution
A plasma processing apparatus with a ring-shaped dielectric cover and a series resonant circuit, including a coil and capacitor, is used to efficiently supply high-frequency power to a second electrode, reducing impedance and enhancing control over the electric field distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-frequency power is supplied to the conductor ring on the outer peripheral side, then the electric field intensity can be adjusted to improve etching uniformity, but impedance increases and power supply efficiency decreases
Solution Approach 1:
A series resonant circuit comprising a coil and capacitor is introduced as an intermediary between the high-frequency power supply and the conductor ring. This resonant circuit matches the impedance and enables efficient power transfer to the conductor ring while maintaining the desired electric field distribution for uniform etching across the wafer surface.
Solution Approach 2:
The impedance characteristics of the power supply system are modified by adjusting the parameters of the series resonant circuit (coil inductance and capacitor capacitance). By tuning these parameters to resonate at the operating frequency, the system achieves optimal impedance matching, thereby improving power supply efficiency without compromising etching uniformity.
2Reliability
If a dielectric cover is placed over the conductor ring to prevent plasma interaction, then component wear is reduced, but high-frequency power supply efficiency decreases due to increased impedance
Solution Approach 1:
The series resonant circuit acts as an intermediary that compensates for the impedance introduced by the dielectric cover. By providing a resonant path for the high-frequency current, the circuit maintains efficient power transfer despite the presence of the dielectric barrier, thus preserving both component protection and power supply efficiency.
3Manufacturing precision
If DC voltage is applied to the focus ring to control electric field distribution, then etching uniformity can be maintained, but the focus ring undergoes wear due to plasma interaction
Solution Approach 1:
Instead of applying DC voltage directly to the focus ring (which causes wear), the invention applies high-frequency voltage through a series resonant circuit that creates the necessary electric field distribution in advance. This preliminary action achieves the desired etching uniformity while avoiding direct DC contact between the focus ring and plasma, thereby reducing wear.
Solution Approach 2:
The DC voltage system is replaced with a high-frequency AC system using a series resonant circuit. This substitution eliminates the need for direct DC contact between the focus ring and plasma environment, replacing the mechanical/electrical wear-prone system with a high-frequency electromagnetic field-based system that achieves the same etching uniformity control without wear.
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 configuration achieves more uniform etching rates across the wafer by effectively controlling the electric field distribution, reducing variations and improving processing yield.
Implementation Method 1
a series resonant circuit, including a coil and capacitor, is used to efficiently supply high-frequency power to a second electrode, reducing impedance
Implementation Method 2
a plasma generation device which supplies an electric field or a magnetic field for generation of the plasma in the processing chamber into the processing chamber
Implementation Method 3
intensity of an electric field, formed above an upper surface of a wafer from a part on a center side to a part on an outer periphery side of the wafer
Data Source
AI summary
A plasma processing apparatus or a plasma processing method that processes a wafer to be processed, which is placed on a surface of a sample stage arranged in a processing chamber inside a vacuum container, using a plasma formed in the processing chamber, the apparatus or method including processing the wafer by adjusting a first high-frequency power to be supplied to a first electrode arranged inside the sample stage and a second high-frequency power to be supplied, via a resonant circuit, to a second electrode which is arranged in an inner side of a ring-shaped member made of a dielectric arranged on an outer peripheral side of a surface of the sample stage on which the wafer is placed, during the processing.