RF Ion Implantation Energy Filter Control via Beam Angle Measurement
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Solution Overview
Problem
Existing ion implantation systems face challenges in accurately determining the final energy of ions due to uncertainties in the beam entrance angle, particularly in RF-based accelerators, leading to ambiguities in the final energy of the ion beam, which affects the depth of penetration into semiconductor wafers.
Innovation Solution
A beam angle measurement system is introduced to determine the angular orientation of the ion beam before it enters the energy filter, allowing for precise control of the accelerator and energy filter parameters to achieve a zero beam angle at the entrance, thereby improving the accuracy of the final energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a beam angle measurement system is introduced to determine angular orientation, then measurement precision of beam angle is improved, but device complexity increases
Solution Approach 1:
A beam angle measurement system is introduced as an intermediary component between the accelerator and energy filter. This system includes a beam position monitor that measures the angular orientation of the ion beam, providing critical data for controlling the final energy delivery. The measurement system acts as a mediator that enables precise control without requiring direct modification of the accelerator or energy filter themselves.
Solution Approach 2:
The system implements feedback control by using the measured beam angle information to adjust accelerator and energy filter parameters. The controller receives real-time data from the beam position monitor and modifies operating parameters to maintain zero beam angle at the energy filter entrance, ensuring accurate final energy delivery. This closed-loop feedback mechanism resolves the measurement precision requirement while managing system complexity through automated control.
2Manufacturing precision
If beam angle is corrected to achieve zero entrance angle at energy filter, then final energy accuracy is improved, but control complexity increases
Solution Approach 1:
The controller uses feedback from the beam position monitor to automatically adjust accelerator and energy filter parameters. By continuously monitoring the beam angle and making real-time corrections, the system maintains zero beam angle at the energy filter entrance, ensuring accurate final energy delivery without requiring manual intervention or complex mechanical adjustments.
Solution Approach 2:
The system achieves beam angle correction by changing operational parameters of the accelerator and energy filter rather than modifying their physical configurations. The controller adjusts parameters such as RF voltage phase and magnetic field strength to control beam trajectory, enabling precise final energy delivery through parameter optimization rather than structural complexity.
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 system enhances the precision of ion implantation by correcting beam angle offsets, ensuring accurate final energy delivery to semiconductor wafers, thus improving the quality of semiconductor products.
Implementation Method 1
An accelerator, such as an RF linear accelerator, is positioned downstream of the ion source and is configured to accelerate the ion beam to a predetermined energy
Implementation Method 2
A beam measurement device is further selectively positioned downstream of the accelerator along the beam path and configured to determine an angular orientation of the ion beam
Data Source
AI summary
An ion implantation system has an ion source configured to form an ion beam along a beam path. An accelerator is downstream of the ion source and configured to accelerate the ion beam to a predetermined energy. An energy filter is downstream of the accelerator and has an entrance configured to accept the ion beam. A beam measurement device can be positioned downstream of the accelerator along the beam path and is configured to determine an angular orientation of the ion beam. A controller further controls one or more of the accelerator and final energy filter based on the angular orientation of the ion beam with respect to the entrance of the energy filter. The controller can control beam parameters of an energy filter formula based on the angular orientation of the ion beam, where the energy filter formula is based on a characterization of the energy filter.