Plasma Chamber Shielding Structure for Stable Radical-Only Etching
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Solution Overview
Problem
Plasma processing devices face instability due to plasma diffusion and non-stationary discharge generation, leading to unintended ion emission during radical-only processing, and insufficient ion shielding in existing designs.
Innovation Solution
A plasma processing device with a processing chamber, radio frequency power supply, magnetic field mechanism, sample stage, first and second shielding plates, and a third shielding plate positioned between them to suppress plasma diffusion and enhance ion shielding, allowing stable plasma processing by controlling the magnetic field and plasma generation regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If plasma is generated below the shielding section, then ions and radicals can be emitted for anisotropic etching, but plasma diffuses upward causing non-stationary discharge and unstable processing
Solution Approach 1:
The shielding section is divided into multiple shielding plates with through-holes arranged at different positions and orientations. This segmentation creates multiple barriers that plasma must pass through, effectively suppressing plasma diffusion while maintaining the ability to switch between anisotropic and isotropic etching modes by controlling plasma generation position.
Solution Approach 2:
Different regions of the shielding structure have different properties - the shielding plates are positioned and oriented to create localized shielding effects. The through-holes are strategically placed to allow radicals to pass while blocking ions in specific directions, enabling local control over plasma behavior without affecting the entire chamber uniformly.
2Adaptability or versatility
If plasma is generated above the shielding section, then only radicals are emitted for isotropic etching, but plasma diffuses downward causing non-stationary discharge and ion emission to the sample
Solution Approach 1:
The shielding section is divided into multiple shielding plates with through-holes arranged at different positions and orientations. This segmentation creates multiple barriers that plasma must pass through, effectively suppressing plasma diffusion while maintaining the ability to switch between anisotropic and isotropic etching modes by controlling plasma generation position.
Solution Approach 2:
The shielding plates with through-holes act as an intermediary structure between the plasma generation region and the sample. This intermediate structure selectively filters plasma components - allowing radicals to pass through to the sample while blocking ions, thereby preventing unwanted ion emission during isotropic etching.
3Device complexity
If single shielding plate is used, then device structure is simple, but ion shielding is insufficient to suppress plasma diffusion
Solution Approach 1:
The shielding function is segmented across multiple shielding plates rather than relying on a single plate. Each plate contributes to the overall shielding effect, and their combined presence creates a more effective barrier against plasma diffusion. The through-holes in different plates are positioned to create a staggered shielding pattern that enhances ion blocking while allowing radical passage.
Solution Approach 2:
The shielding approach transitions from a single-plane shield to a multi-plane three-dimensional structure. The shielding plates are positioned at different locations and oriented at different angles, creating shielding in multiple spatial dimensions. This dimensional expansion significantly improves ion shielding effectiveness compared to a single flat shield.
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 device achieves improved ion shielding and stable plasma processing by preventing plasma diffusion and non-stationary discharge generation, enabling uniform and stable etching processes for both anisotropic and isotropic etching.
Implementation Method 1
a magnetic field forming mechanism for forming a magnetic field in the processing chamber
Implementation Method 2
a radio frequency power supply for supplying microwave radio frequency power
Data Source
AI summary
In order to execute stable processing by suppressing plasma diffusion and non-stationary discharge generation, there is provided a plasma processing device which includes a processing chamber in which a sample stage is provided for placing a sample thereon, an exhaust unit for evacuating the processing chamber, a magnetic field forming mechanism for forming a magnetic field in the processing chamber, and a power supply unit that supplies radio frequency power for generating plasma to the inside of the processing chamber evacuated by the exhaust unit and has the magnetic field formed by the magnetic field forming mechanism. The processing chamber includes a shielding section which divides an inner part of the processing chamber into a first area at a side for supplying the radio frequency power from the power supply unit and a second area at a side where the sample stage is disposed. The shielding section includes a first shielding plate disposed at the side that faces the first area, in which a first opening is formed, a second shielding plate disposed at the side that faces the second area, in which a second opening is formed at the center, and a third shielding plate disposed between the first and the second shielding plates.