Ion Beam Extraction Electrodes with Sub-Grids
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Solution Overview
Problem
Conventional ion beam apparatuses face challenges in maintaining uniformity of the ion beam due to increased divergence and decreased flux towards the edges, limiting process window flexibility as wafer sizes grow, and difficulty in fabricating extraction electrodes with spatially varying diameters.
Innovation Solution
The use of extraction electrodes with sub-grids, where different potentials can be applied to control the ion beam, allowing for independent adjustment of energy, flux, and irradiation angle to improve uniformity, and the formation of extraction electrodes with sub-grids that reflect the actual ion beam distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If extraction electrodes with spatially different diameters are fabricated to increase ion beam uniformity, then ion beam uniformity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The extraction electrode is divided into multiple independent sub-grids (first sub-grid, second sub-grid, third sub-grid) with different diameters. Each sub-grid can be independently controlled, allowing differential voltage application to extract ions uniformly from both center and edge regions of the plasma chamber without requiring a single complex electrode structure.
Solution Approach 2:
The extraction electrode structure is made dynamically controllable by applying different voltages to different sub-grids based on process conditions. This allows the effective extraction pattern to be adjusted dynamically, enabling the same electrode to function as if it had different diameters for different operational requirements.
2Area of stationary object
If conventional extraction electrodes are used with increased wafer size, then processing capacity is improved, but ion beam uniformity control becomes more difficult
Solution Approach 1:
By segmenting the extraction electrode into multiple sub-grids, the system can independently control ion extraction from different radial positions. This segmentation allows the extraction pattern to be scaled and adjusted to match larger wafer sizes while maintaining uniform ion beam distribution across the entire area.
Solution Approach 2:
Different sub-grids can be assigned different voltages and extraction characteristics tailored to their specific positions (center vs. edge). This local quality approach ensures that each region of the extraction electrode contributes optimally to the overall uniformity, even as the total processing area increases with larger wafers.
3Ease of manufacture
If the plasma density decreases from center to edge, then ion beam extraction is simplified, but ion beam uniformity deteriorates
Solution Approach 1:
The system dynamically adjusts the voltage applied to each sub-grid based on the radial position and local plasma density. By making the extraction process adaptive rather than static, the system compensates for the natural plasma density gradient, extracting sufficient ions from edge regions while maintaining appropriate extraction from center regions, thus achieving uniformity without oversimplifying the process.
Solution Approach 2:
The extraction voltage parameter is changed across different sub-grids to compensate for plasma density variations. Higher voltages can be applied to edge sub-grids where plasma density is lower, while center sub-grids use lower voltages, thereby balancing the ion extraction rate across the entire plasma chamber and achieving uniform ion beam output.
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 approach enhances the uniformity of the ion beam by controlling divergence and flux distribution, improving the reliability of semiconductor processes and expanding the process window without requiring changes to the ion beam apparatus or plasma uniformity.
Implementation Method 1
A voltage may be applied between the extraction electrodes to extract an ion beam from the ion source
Implementation Method 2
a repulsive force between charged particles included in an ion beam may increase a divergence toward an edge of the ion beam
Data Source
AI summary
An apparatus and/or method for controlling an ion beam may be provided, and/or a method for preparing an extraction electrode for the same may be provided. In the apparatus, a plurality of extraction electrodes may be disposed in a path of an ion beam. At least one extraction electrode may include a plurality of sub-grids.