Stepped-Impedance Resonator in Plasma Chambers for Uniform Density
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in achieving uniform plasma density distribution and efficient chamber cleaning due to difficulties in introducing electromagnetic waves and cleaning radicals through the center of the shower head, leading to suboptimal processing results.
Innovation Solution
The plasma processing apparatus incorporates a waveguide structure with a resonator that includes a first and second waveguide with different characteristic impedances, allowing for a shorter resonator length and preventing abnormal discharges, while using a dielectric part to enhance uniform plasma generation and cleaning by introducing electromagnetic waves and radicals through the center of the shower head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional waveguide structure is used to introduce electromagnetic waves through the shower head, then plasma can be generated, but the resonator length becomes excessively long and abnormal discharges occur
Solution Approach 1:
The patent changes the characteristic impedance parameter of the waveguide sections. By dividing the waveguide into a first section with characteristic impedance Z1 and a second section with characteristic impedance Z2 (where Z2 > Z1), the resonator length is reduced while maintaining reliable plasma generation without abnormal discharges.
2Manufacturing precision
If electromagnetic waves are introduced through the center of the shower head, then plasma generation is achieved, but uniform plasma density distribution cannot be obtained
Solution Approach 1:
The patent applies local quality by creating different impedance regions within the waveguide structure. The first waveguide section and second waveguide section have different characteristic impedances, creating localized impedance variations that produce uniform plasma density distribution across the substrate surface.
3Reliability
If a longer resonator is used to ensure reliable plasma generation, then plasma can be generated, but the device size increases and processing efficiency decreases
Solution Approach 1:
By changing the characteristic impedance parameter from a uniform value to a stepped distribution (Z1 followed by Z2 where Z2 > Z1), the resonator length is significantly reduced. This parameter change maintains plasma generation reliability while improving processing efficiency through reduced device size and shorter processing cycles.
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 enables improved uniformity of plasma density distribution and efficient chamber cleaning by allowing for a shorter resonator length, preventing abnormal discharges, and ensuring uniform radical supply, thus enhancing processing efficiency.
Implementation Method 1
a waveguide structure configured to propagate an electromagnetic wave that is a VHF wave or a UHF wave
Implementation Method 2
to generate plasma within the chamber
Implementation Method 3
The waveguide structure includes a resonator that resonates the electromagnetic waves inside the waveguide structure
Data Source
AI summary
Disclosed is a plasma processing apparatus including a chamber and a waveguide structure. The waveguide structure is configured to propagate electromagnetic waves, which are VHF waves or UHF waves, in order to generate plasma within the chamber. The waveguide structure includes a resonator for electromagnetic waves. The resonator includes a first waveguide, a second waveguide, and a load impedance portion. The first waveguide has a first characteristic impedance. The second waveguide has a second characteristic impedance. The second waveguide is terminated at a short-circuit end having a ground potential. The load impedance portion is connected between the first waveguide and the second waveguide. The second characteristic impedance is greater than the first characteristic impedance.