Ring Resonator Microwave Plasma Layout for Uniform Etching
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Solution Overview
Problem
Plasma processing apparatuses face challenges in achieving uniform plasma density distribution on target substrates, leading to non-uniform etching results due to plasma diffusion and magnetic field interactions, which complicates the adjustment of plasma generation regions and increases manufacturing costs.
Innovation Solution
A plasma processing apparatus with a ring resonator excited by a parallel flat plate line and phase adjusting units to ensure even excitation, reducing non-uniformities and simplifying the structure for improved axisymmetry and plasma uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a static magnetic field is applied to control plasma distribution, then plasma generation can be ensured under difficult conditions, but plasma loss occurs and uniformity deteriorates near wall surfaces
Solution Approach 1:
The patent applies a static magnetic field with specific flux density (0.02 to 0.2 Wb/m²) to create ECR conditions that enable reliable plasma generation. By controlling the magnetic field strength to match the microwave frequency (2.45 GHz), the system achieves consistent plasma generation across the processing chamber while managing plasma loss through optimized field distribution.
2Manufacturing precision
If multiple waveguides are used to improve plasma uniformity, then plasma distribution can be enhanced, but device complexity increases
Solution Approach 1:
The patent divides the electromagnetic field generation system into multiple independent waveguide segments, each positioned at a specific distance from the processing chamber. This segmentation allows each waveguide to contribute to a specific region of plasma generation, and by adjusting the number, position, and orientation of individual segments, the system achieves uniform plasma distribution while maintaining modular simplicity that avoids excessive complexity.
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 allows for accurate adjustment of electromagnetic field distributions, reducing plasma loss and achieving uniform plasma processing on target substrates, thereby enhancing etching quality and reducing manufacturing costs.
Implementation Method 1
a ring resonator unit that is disposed on an outer periphery of the parallel flat plate line portion and receives the microwave power propagated from the parallel flat plate line portion
Implementation Method 2
standing waves are excited, a non-uniformity in the azimuth direction corresponding to antinodes and nodes of the standing waves exists at a fixed position
Implementation Method 3
A slot antenna is provided on the processing chamber side of the ring resonator, and in the ring resonator, microwaves are radiated from the slot antenna to the processing chamber according to an electromagnetic field formed in a resonance mode
Implementation Method 4
it is known that when microwaves are used as electromagnetic waves for plasma generation and a static magnetic field that matches a period of electron cyclotron operation with a frequency of the microwaves is used, an electron cyclotron resonance (hereinafter, referred to as ECR) phenomenon occurs
Implementation Method 5
there is an effect that by using an interaction between the electromagnetic waves and the static magnetic field, the plasma can be generated even under an operation condition where the plasma is usually difficult to be generated
Data Source
AI summary
A plasma processing apparatus includes: a vacuum chamber that includes a plasma processing chamber in which a substrate is to be plasma-processed and that can exhaust an inside of the plasma processing chamber to vacuum; and a microwave power supply unit that supplies a microwave power to the vacuum chamber via a circular waveguide. The vacuum chamber includes: a parallel flat plate line portion that is connected to the circular waveguide and receives a microwave power propagated from the circular waveguide; a ring resonator unit that is disposed on an outer periphery of the parallel flat plate line portion and receives the microwave power propagated from the parallel flat plate line portion; a cavity portion that receives a microwave power radiated from a slot antenna formed in the ring resonator unit; and a microwave introduction window that separates the cavity portion from the plasma processing chamber. The parallel flat plate line portion includes a phase adjusting unit for adjusting a phase of microwaves propagating from the parallel flat plate line portion to the ring resonator unit at a boundary portion with the ring resonator unit.