Multi-Coil Ion Source Layout for Uniform Ion Beam Etching
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Solution Overview
Problem
The non-uniformity of ion beam etching processes is caused by the convex distribution of plasma density in conventional ion sources, leading to inconsistent etching results across semiconductor devices.
Innovation Solution
A U-shaped discharge cavity with multiple discharge coils and power distribution regulation to form multiple plasma discharge regions, allowing for uniform plasma density distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional large-aperture ion source with a single helical coil antenna is used to generate ICP, then the ion source can be simple in structure, but the plasma density distribution becomes convex (highest at center, decreasing radially), resulting in non-uniform ion beam etching
Solution Approach 1:
The single helical coil antenna is segmented into multiple discharge coils (first, second, third, and fourth discharge coils) positioned at different locations around the discharge cavity. Each coil can be independently controlled to generate plasma in specific regions, allowing the plasma density distribution to be divided and regulated across different zones to achieve overall uniformity.
Solution Approach 2:
Different discharge coils are assigned different power levels through the power divider to create localized plasma density adjustments. The first and second discharge coils (at cylindrical and U-shaped protruding portions) and third and fourth discharge coils (at inner side and bottom walls) can be tuned to provide higher power to edge regions and lower power to center regions, compensating for the natural convex distribution and achieving uniform plasma density across the discharge cavity.
2Manufacturing precision
If a single helical coil antenna generates ICP in a common ion source structure, then the device complexity is low, but the plasma is mainly diffused and exhibits convex distribution, causing non-uniform etching
Solution Approach 1:
The plasma generation system is segmented into multiple independent discharge coils rather than using a single coil. This segmentation allows each coil to be optimized for its specific region, with the power divider enabling independent control of each coil's power level to achieve uniform plasma distribution.
Solution Approach 2:
The power distribution to each discharge coil is made dynamically adjustable through the power divider, allowing the system to adapt and optimize plasma density distribution in real-time. This dynamic control enables compensation for the natural convex plasma distribution by adjusting power levels to different regions.
3Manufacturing precision
If conventional ion source design is used, then the structure is simple, but the ion density flux through ion grid meshes exhibits convex state, leading to non-uniform etching results
Solution Approach 1:
The discharge cavity is segmented into multiple regions with dedicated discharge coils positioned at the cylindrical outer side wall, U-shaped protruding portion, inner side wall, and bottom wall. This spatial segmentation allows independent control of plasma generation in each region to achieve uniform ion density flux through the ion grid meshes.
Solution Approach 2:
Each discharge coil is configured to provide localized plasma generation with tailored power levels. The power divider enables each coil to deliver appropriate power to its region, creating local plasma density adjustments that collectively produce uniform ion density distribution across the entire discharge cavity and through the ion grid meshes.
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 achieves uniform ion beam etching by optimizing plasma density distribution, enhancing the uniformity of etching processes.
Implementation Method 1
first discharge coils, second discharge coils... Both the first discharge coils and the second discharge coils are connected to a power divider... a first plasma discharge region for plasma discharge is formed... a second plasma discharge region for plasma discharge is formed
Implementation Method 2
the gas is passed into the ion source and the plasma is generated... a first plasma discharge region for plasma discharge is formed... a second plasma discharge region for plasma discharge is formed
Data Source
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AI summary
The present application relates to an ion source apparatus and a usage method therefor, and a vacuum treatment system. The apparatus comprises a discharge cavity, wherein the cylindrical central axis thereof is the central axis of the ion source apparatus, and a wafer is arranged at a position on the central axis of the ion source apparatus that is relative to an open end of the discharge cavity. The ion source apparatus further comprises: a first discharge coil, wherein the closed end of the discharge cavity is U shaped, the first discharge coil is sleeved on a cylindrical outer side wall of the discharge cavity, and a first plasma discharge area for plasma discharge is formed at a position in the discharge cavity that is close to the cylindrical outer side wall; a second discharge coil, which is arranged on a U-shaped protruding portion of the discharge cavity, wherein a second plasma discharge area for plasma discharge is formed at a position in the discharge cavity that is close to the U-shaped protruding portion; and at least two layers of ion grid meshes, which are arranged at the open end of the discharge cavity. Both the first discharge coil and the second discharge coil are connected to a power divider.