Ion Implanter Plasma Homogeneity via Segmented Source Bodies
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Solution Overview
Problem
Ion implanters face challenges in achieving plasma homogeneity over large-sized substrates, leading to reduced plasma density and increased implantation duration, especially when treating large or multiple small-sized substrates simultaneously.
Innovation Solution
The ion implanter design incorporates at least two cylindrical source bodies with magnetic confinement coils and external radiofrequency antennas, allowing for a maximized magnetic field that extends the plasma coverage and adjusts homogeneity, along with a common radiofrequency generator and tuning systems to optimize plasma distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the source body diameter is increased to treat large-sized substrates, then the substrate coverage area is improved, but the plasma density decreases due to distance from the antenna
Solution Approach 1:
The single large source body is divided into multiple smaller source bodies (at least two) arranged in an array. Each source body maintains high plasma density by staying close to its dedicated antenna, while the collective array covers the entire large substrate area. This segmentation resolves the contradiction by allowing both adequate coverage and maintained plasma density through distributed sources.
2Area of stationary object
If the substrate is placed farther from the source body to accommodate large substrates, then the substrate coverage is improved, but the plasma density at the substrate level is substantially reduced
Solution Approach 1:
Multiple small source bodies are distributed across the substrate surface, each positioned close to its corresponding antenna. This arrangement allows large substrates to be covered while maintaining short distances between each local source and the substrate, thereby preserving high plasma density at the substrate level across the entire coverage area.
3Device complexity
If a single large source body is used, then the device complexity is reduced, but the plasma homogeneity over the substrate surface deteriorates
Solution Approach 1:
The plasma generation system is segmented into multiple independent source bodies, each producing localized plasma with high homogeneity near its antenna. The superposition of these multiple homogeneous plasma regions creates overall plasma uniformity across the entire substrate surface, resolving the homogeneity issue while accepting increased device complexity.
Solution Approach 2:
Each source body creates a localized plasma region with optimal characteristics for its specific position. By adjusting individual source parameters, local plasma quality can be optimized for different substrate regions, achieving global homogeneity through local optimization of each segmented source.
4Area of stationary object
If the plasma density at the substrate is reduced, then the implantation can be performed on large substrates, but the implantation duration is substantially increased
Solution Approach 1:
Multiple high-density plasma sources are distributed across the substrate, allowing simultaneous implantation over the entire large substrate area. This parallel processing approach maintains high implantation flux throughout the process, significantly reducing the total implantation duration compared to using a single large low-density source.
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 ensures improved plasma homogeneity over a larger surface area, enabling efficient ion implantation on large-sized substrates and multiple small-sized substrates, reducing implantation time and maintaining high plasma density.
Implementation Method 1
the ion implanter is remarkable in that it comprises at least one confinement coil per source body
Implementation Method 2
the magnetic field is maximum at the place of the formation of the plasma. The field lines widen in the enclosure, which causes an extension of the plasma
Implementation Method 3
Around the source body, takes place the radiofrequency antenna provided to generate the plasma
Implementation Method 4
polarizing it in negative voltage, from a few tens of volts to a few tens of kilovolts (generally less than 100 kV), in order to create a electric field capable of accelerating the ions from the plasma towards the substrate
Data Source
Figure 1
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Figure 3~6
AI summary
The invention relates to an ion implanter comprising an enclosure ENV containing a substrate carrier PPS connected to a substrate supply ALT by means of a high-voltage electrical passage PET, said enclosure ENV being provided with pumping means PP, PS and also comprising at least two cylindrical, obstacle-free source bodies CS1, CS2 arranged facing the substrate carrier. Said implanter is characterised in that it comprises at least one containment coil BCI1 -BCS1, BCI2-BCS2 per source body CS1, CS2.