Ion Source Electrode Cleaning by Adjustable Beam Irradiation
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Solution Overview
Problem
The deposition of insulating substances on electrodes in ion implantation apparatuses leads to electrical insulation and abnormal discharges, reducing the operational efficiency and longevity of the ion source, as these substances are not effectively removed by existing methods.
Innovation Solution
An ion source with a plasma chamber and a suppression electrode, where the distance between the plasma chamber and the suppression electrode is increased during cleaning, allowing a wider irradiation area for an ion beam produced from a cleaning gas to remove deposition substances, and a control device monitors the potential or current to determine the completion of cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the distance between the plasma chamber and suppression electrode is increased during cleaning, then the ion beam irradiation area is widened and cleaning effectiveness is improved, but the device complexity increases due to the need for a drive mechanism
Solution Approach 1:
The suppression electrode is made movable along the ion beam extraction direction through a drive mechanism, allowing the distance between the plasma chamber and suppression electrode to be dynamically adjusted. During cleaning mode, the distance is increased to widen the ion beam irradiation area and improve cleaning effectiveness. During normal operation, the distance is reduced to maintain proper electrode positioning. This dynamic adjustment resolves the contradiction by allowing the system to optimize cleaning effectiveness when needed while maintaining normal operational configuration otherwise.
2Reliability
If the ion beam is defocused to strike the suppression electrode and ground electrode for cleaning, then the deposition substances are removed, but the precision of ion beam extraction is reduced
Solution Approach 1:
The ion source operates in periodic cycles, alternating between normal operation mode and cleaning mode. During normal operation, the ion beam is focused for precise ion extraction and implantation. During cleaning mode, the ion beam is defocused to strike the suppression electrode and ground electrode, removing deposition substances. The control device manages these periodic transitions, allowing the system to maintain high extraction precision during production while periodically cleaning electrodes to prevent insulation issues, thus resolving the contradiction between reliability and precision.
3Reliability
If the cleaning mode is implemented with moved extraction electrodes, then the plasma-assisted cleaning is improved, but the operation time is increased due to mode switching
Solution Approach 1:
The ion source performs self-cleaning by utilizing its own ion beam generation capability. During cleaning mode, the ion beam is directed to strike the suppression electrode and ground electrode, allowing these components to clean themselves of deposition substances without requiring external cleaning equipment or manual intervention. The control device automatically manages the mode switching based on operational needs. This self-service approach improves cleaning effectiveness while minimizing time loss, as the cleaning process is integrated into the normal operation cycle and does not require separate external cleaning procedures.
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 method effectively widens the range for ion beam cleaning, allowing for thorough removal of deposition substances, preventing electrical insulation and ensuring normal operation by automatically switching between cleaning and normal modes based on electrode potential or current stability.
Implementation Method 1
irradiating the suppression electrode with an ion beam produced from a cleaning gas to clean the suppression electrode
Implementation Method 2
An ion implantation apparatus generates plasma in a plasma chamber using a halogen-containing gas or vapor as a raw material
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3C
AI summary
An ion source includes a plasma chamber, and a suppression electrode disposed downstream of the plasma chamber, and is operable to irradiate the suppression electrode with an ion beam produced from a cleaning gas to clean the suppression electrode. Prior to cleaning, the ion source moves the suppression electrode or the plasma chamber in a first direction to increase a distance between the plasma chamber and the suppression electrode.