Plasma Mounting Table Surface Treatment for Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In plasma processing for semiconductor fabrication, metal mounting tables with rough surfaces tend to produce unstable plasma due to high surface roughness and alumina particle residue, leading to abnormal waveforms and plasma instability.
Innovation Solution
A two-step surface treatment process involving a first blasting with non-sublimation materials like alumina particles followed by a second blasting with sublimation materials like dry ice to maintain surface roughness and round irregularities, stabilizing the plasma by adjusting impedance and reducing abnormal waveforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blasting process is performed on a metal mounting table to create a rough surface, then particle generation is suppressed and wafer sliding is prevented, but plasma stability deteriorates due to alumina particle residue
Solution Approach 1:
The blasting process is divided into two separate stages: first blasting with alumina particles to create roughness and suppress particle generation, followed by second blasting with dry ice particles to remove residual alumina and stabilize plasma. This segmentation allows each blasting material to perform its specific function without interfering with the other.
Solution Approach 2:
The patent utilizes the sublimation property of dry ice (solid CO2) to automatically remove residual alumina particles. The dry ice particles sublimate upon contact with the mounting table surface, carrying away adhered alumina particles and leaving no residue that would affect plasma stability.
2Strength
If alumina blasting is performed to enhance thin film adhesion, then adhesion is improved, but plasma stability deteriorates due to remaining alumina particles
Solution Approach 1:
The adhesion enhancement and plasma stabilization functions are separated into two sequential blasting operations. The first blasting with alumina provides the roughness needed for thin film adhesion, while the second blasting with sublimating dry ice removes excess alumina particles that would otherwise destabilize the plasma.
Solution Approach 2:
The patent exploits the phase transition of dry ice from solid to gas (sublimation) to remove residual alumina particles. This phase change allows the dry ice particles to effectively clean the surface without leaving any solid residue that would affect plasma stability.
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 process stabilizes the plasma by reducing impedance and preventing abnormal waveforms, ensuring a stable plasma process and effective film formation on substrates.
Implementation Method 1
performing a first surface treatment by spraying a non-sublimation blast material as a non-sublimation material onto a mounting surface of the metal mounting table
Implementation Method 2
performing a second surface treatment by spraying a sublimation blast material as a sublimation material onto the mounting surface
Implementation Method 3
spraying a sublimation blast material as a sublimation material onto the mounting surface
Implementation Method 4
having an excited argon gas to collide against the mounting surface
Data Source
AI summary
There is provided a method of performing a surface treatment with respect to a metal mounting table for mounting a substrate to be plasma-processed, the mounting table functioning as a lower electrode configured to generate a plasma by a high frequency power applied between an upper electrode and the lower electrode. The method includes: performing a first surface treatment by spraying a non-sublimation blast material as a non-sublimation material onto a mounting surface of the metal mounting table on which the substrate is mounted, followed by a second surface treatment by spraying a sublimation blast material as a sublimation material onto the mounting surface.