Ion Beam Control System for Rapid Instability Switch-Off
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Solution Overview
Problem
Ion implantation systems face non-uniform implantations due to instabilities in ion beams, leading to degraded semiconductor devices, as existing mechanisms are limited to arc discharge sources and cannot effectively detect and mitigate instabilities in non-arc discharge sources.
Innovation Solution
Implementing a system that rapidly switches off an ion beam generated by a non-arc discharge source, such as an electron gun or RF ion source, upon detecting instabilities, and initiates a controlled recovery process to ensure uniform implantation by monitoring beam characteristics like current and flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional mechanism is used to switch off an arc discharge source on detected ion beam instabilities, then arc discharge source instabilities can be mitigated, but the mechanism is limited to arc discharge sources and cannot be applied to non-arc discharge sources
Solution Approach 1:
The patent develops a universal instability detection and mitigation mechanism that can be applied to both arc discharge sources and non-arc discharge sources (such as electron gun ion sources and RF ion sources). The system uses a beam characteristic monitor to detect instabilities and a controller to switch off the ion beam regardless of the source type, making the solution universally applicable across different ion source technologies while maintaining beam stability.
2Manufacturing precision
If the ion beam is rapidly switched off on detecting an instability, then non-uniform implantation is prevented, but the ion beam generation is interrupted
Solution Approach 1:
The system implements a feedback control mechanism where beam characteristics (such as beam current) are continuously monitored during ion beam generation. When an instability is detected through the monitor, the controller rapidly switches off the ion beam to prevent non-uniform implantation. After switching off, the controller initiates a recovery process that allows the ion source to stabilize before resuming beam generation, thus maintaining implantation uniformity while minimizing interruption to productivity.
3Quantity of substance
If multiple passes are made over each region of the wafer to obtain sufficient dosing, then adequate ion implantation is achieved, but an error in a single pass results in unwanted dose variation
Solution Approach 1:
The system performs preliminary detection of beam instabilities before they can cause dose variations during multiple scan passes. By continuously monitoring beam characteristics and switching off the ion beam upon detecting an instability, the system prevents errors from occurring during any pass. This preliminary action ensures that all multiple passes over wafer regions maintain consistent dosing without the risk of unwanted dose variations from beam instabilities.
Data Source
AI summary
An ion beam is rapidly switched off during ion implantation on detecting a beam instability. The ion beam is generated or provided by a non-arc discharge based ion source, such as an electron gun ion source or an RF ion source. The ion beam is scanned across a workpiece from a starting location toward an ending location. During the scanning, one or more beam characteristics are monitored, such as beam current, beam flux, shape, and the like. An instability is detected when one or more of the beam characteristics deviate from acceptable values or levels. The ion beam is rapidly turned off on the detected instability.