Ion Implanter RF Phase Scan for Faster LINAC Stage Tuning
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Solution Overview
Problem
Current high energy ion implanters, particularly those based on linear accelerators (LINACs), require lengthy setup procedures to adjust RF voltage and phase for each acceleration stage, which is inefficient and time-consuming.
Innovation Solution
A method and system for tuning ion implanters that involve applying an RF signal with a determined frequency and amplitude, performing a phase scan across multiple phase values, and recording arrival times to determine a zero synchronous phase for each acceleration stage, allowing for precise control of ion beam energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional RF voltage and phase adjustment procedures are used for each acceleration stage, then the ion implanter can achieve proper beam energy, but the setup procedure becomes lengthy and time-consuming
Solution Approach 1:
The patent changes the approach from manually adjusting RF voltage and phase parameters to automatically determining optimal parameters through time-of-flight measurements. The system measures the actual time ions take to traverse each acceleration stage and uses this data to calculate the precise RF phase and voltage settings needed, thereby achieving accurate beam energy control while eliminating lengthy manual setup procedures.
2Use of energy by moving object
If multiple acceleration stages are used to reach high ion energies, then the ion implanter can achieve targeted final energy, but the complexity of synchronizing RF phases across stages increases
Solution Approach 1:
The patent replaces the complex mechanical/electrical synchronization system with a measurement-based control approach. Instead of using a master clock to synchronize RF phases across multiple acceleration stages, the system measures the actual time-of-flight of ions through each stage and uses these measurements to determine the appropriate RF settings, thereby achieving high ion energies while reducing synchronization complexity.
3Reliability
If manual adjustment procedures are used for RF settings, then each acceleration stage can be tuned, but the process becomes inefficient and requires extensive operator intervention
Solution Approach 1:
The patent implements a self-service tuning system where the ion implanter automatically determines its own RF settings based on time-of-flight measurements. The system performs self-diagnosis and self-adjustment by measuring ion traversal times and calculating the optimal RF phase and voltage for each acceleration stage, thereby maintaining tuning accuracy while dramatically improving productivity by eliminating manual intervention.
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 reduces tuning time for multi-stage linear accelerators, facilitates recipe generation, and eliminates the need for a master clock to synchronize RF phases across stages, enhancing operational efficiency.
Implementation Method 1
a linear accelerator, comprising a plurality of acceleration stages to accelerate the ion beam. As such, a given acceleration stage of the linear accelerator may be driven by an RF signal
Implementation Method 2
performing a phase scan using the RF signal. The phase scan may include varying a phase of the RF signal at the acceleration stage over a plurality of phase values; and recording a plurality of arrival times at a monitor, situated downstream of the acceleration stage
Data Source
AI summary
A method to operate an ion implanter. The method may include conducting an ion beam into an acceleration stage of a linear accelerator in the ion implanter, where the ion beam is a bunched ion beam. The method may also include applying an RF signal to the acceleration stage while the ion beam passes through the acceleration stage, the RF signal comprising a determined frequency and a determined amplitude, and performing a phase scan using the RF signal. The phase scan may include varying a phase of the RF signal at the acceleration stage over a plurality of phase values; and recording a plurality of arrival times at a monitor, situated downstream of the acceleration stage, the plurality of arrival times corresponding to the plurality of phase values, respectively.