Ion Implantation Filament Uniform Cross Section
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Solution Overview
Problem
Conventional ion-implantation apparatus filaments tend to break at bending points due to non-uniform plasma concentration, leading to shortened filament life and increased maintenance and production costs.
Innovation Solution
A filament design with a connecting portion that maintains uniform cross-sectional dimensions before and after bending, ensuring consistent resistance and plasma generation, preventing excessive plasma concentration and filament corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the filament is bent several times to form a specific shape, then the filament can be installed in the ionization chamber, but the cross-sectional area at the bend points becomes smaller causing larger resistance and non-uniform plasma concentration
Solution Approach 1:
The filament is pre-formed with a connecting portion that has a larger cross-sectional area before bending. This preliminary design ensures that when the filament is bent into its final shape, the connecting portion maintains sufficient cross-sectional area and low resistance, preventing the problem of non-uniform plasma concentration at bend points.
2Shape
If the filament is bent several times to form a specific shape, then the filament can be installed in the ionization chamber, but the resistance at bending points becomes larger causing more hot electrons and higher plasma concentration
Solution Approach 1:
The connecting portion of the filament is designed with a larger cross-sectional area specifically at the bend points, creating local quality differentiation. This local design change reduces resistance at the connecting portion, preventing excessive hot electron generation and plasma concentration at these critical locations, thereby extending filament life.
3Device complexity
If the cross-sectional dimension of the connecting portion is reduced to match the end portions, then the filament structure is simplified, but the resistance increases and plasma concentration becomes non-uniform
Solution Approach 1:
The cross-sectional dimension parameter of the connecting portion is intentionally changed to be larger than that of the end portions. This parameter change ensures uniform plasma concentration by maintaining low resistance at the connecting portion, while the overall filament structure remains relatively simple.
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 uniform cross-sectional dimensions of the filament reduce the likelihood of breakage, extending its life and lowering maintenance and production costs for the ion-implantation apparatus.
Implementation Method 1
the filament of the ionization chamber filament generates hot electrons after supplying with current
Implementation Method 2
the hot electrons and ion-source gas collide to each other to generate plasma
Data Source
AI summary
A filament includes first and second end portions between which a connecting portion is arranged. The first and second end portions are electrically connected to a power supply device. The first end portion is bent with respect to the second end portion through the connecting portion. A cross-sectional dimension of the bent connecting portion is the same as cross-sectional dimensions of the first and second end portions. Also disclosed are an ionization chamber and an ion-implantation apparatus. The cross-sectional dimension of the filament is uniform. The resistance of respective portions of the filament is the same. The number of the hot electrons generated at respective portions by powering the filament is the same. The hot electrons and ion-source gas collide to generated plasma. The plasma concentration around the filament is uniform, to avoid the emergence of corrosion of the filament at certain portion caused by an over high plasma concentration.