Annular Waveguide With Segmentation Pins For Plasma Uniformity
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Solution Overview
Problem
Existing plasma processing technologies using high-frequency power in the VHF band face challenges in achieving uniform film thickness distribution, particularly exhibiting double symmetry and one-sided distributions due to non-uniform plasma density along the circumferential direction, which affects the quality of plasma processing results.
Innovation Solution
A plasma processing apparatus with an annular waveguide and protruding pins arranged circumferentially within the waveguide to distribute electromagnetic waves uniformly, ensuring a consistent plasma density across the processing area by modifying the electric field distribution and plasma density patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-frequency power is supplied to generate plasma, then plasma processing can be performed, but non-uniform plasma density distribution occurs in the circumferential direction
Solution Approach 1:
The waveguide is divided into multiple segments by providing a plurality of pins that protrude into the waveguide interior from its outer peripheral surface. These pins segment the electromagnetic wave propagation paths, creating multiple reflection points that distribute plasma-generating electromagnetic waves more uniformly in the circumferential direction, thereby resolving the non-uniform plasma density distribution.
Solution Approach 2:
The pins protruding into the waveguide interior add a dimensional element to the electromagnetic wave interaction. By creating multiple reflection surfaces at different positions within the waveguide cross-section, the electromagnetic waves are redirected along multiple paths, achieving uniform circumferential distribution through spatial dimensionality rather than simple linear propagation.
2Device complexity
If a simple waveguide structure is used, then device complexity is reduced, but electromagnetic wave distribution uniformity deteriorates
Solution Approach 1:
The waveguide structure is segmented by adding multiple pins that protrude into its interior. This segmentation creates multiple electromagnetic wave reflection surfaces without fundamentally changing the waveguide's basic structure, maintaining relative simplicity while achieving improved uniformity through the segmented reflection pattern.
Solution Approach 2:
The pins act as intermediary elements within the waveguide, mediating the interaction between the electromagnetic waves and the waveguide walls. These intermediary pins create additional reflection paths and distribute the electromagnetic energy more uniformly, serving as a simple yet effective mediator between the simple waveguide structure and the uniform distribution requirement.
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 the uniformity of film thickness and plasma density in the circumferential direction, improving the overall quality of plasma processing without the need for wafer rotation, thus reducing costs and avoiding potential degradation from rotation mechanisms.
Implementation Method 1
a waveguide configured to propagate electromagnetic waves generated based on the high-frequency power to a plasma processing space formed between the stage and the electrode
Implementation Method 2
a plurality of pins are provided to protrude into the waveguide, and the plurality of pins are arranged at respective positions separated from one another along a circumferential direction
Implementation Method 3
plasma generated based on high-frequency power of 30 MHz or more
Data Source
AI summary
A plasma processing apparatus for processing an object to be processed with plasma, includes: a stage on which the object to be processed is placed; an electrode arranged at a position facing the stage and to which high-frequency power having a frequency of 30 MHz or more is supplied; and a waveguide configured to propagate electromagnetic waves generated based on the high-frequency power to a plasma processing space formed between the stage and the electrode, wherein the waveguide is formed in an annular shape in a plan view so that an end portion of the waveguide near the plasma processing space surrounds an outer periphery of the electrode, a plurality of pins are provided to protrude into the waveguide, and the plurality of pins are arranged at respective positions separated from one another along a circumferential direction in the plan view.