RF Ion Beam Mass Analysis With Energy Spread Reduction
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Solution Overview
Problem
Existing ion implantation systems face challenges in achieving high flux and narrow energy spread for mass analyzed ion beams, particularly in compact systems, due to limitations in electrodynamic mass analysis (EDMA) designs and the absence of magnetic analyzers, which are large and costly.
Innovation Solution
An apparatus and method utilizing an electrodynamic mass analysis (EDMA) assembly with a deflection assembly and energy spread reducer (ESR), employing RF voltage signals at specific frequencies to deflect and accelerate ions, resulting in a mass analyzed bunched ion beam with reduced energy spread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic analyzer is used for mass analysis, then mass separation precision is improved, but device size and cost increase significantly
Solution Approach 1:
The patent replaces the magnetic analyzer (mechanical/electromagnetic system) with an electrodynamic mass analysis system using RF electrodes. The RF electrodes create oscillating electric fields that selectively transmit ions of specific masses through resonant excitation, eliminating the need for large magnetic fields and complex mechanical components while achieving comparable mass separation precision
Solution Approach 2:
The patent changes the operating parameters from static magnetic fields to dynamic RF electric fields. By controlling the RF frequency and amplitude, the system can selectively resonate with and transmit ions of specific masses, providing adjustable mass separation without the fixed geometry constraints of magnetic analyzers
2Device complexity
If EDMA is used for mass analysis in compact systems, then device size is reduced, but ion flux and energy spread control deteriorate
Solution Approach 1:
The patent divides the electrodynamic mass analysis system into multiple RF electrode stages, each tuned to specific frequencies. This segmentation allows different mass ranges to be analyzed simultaneously or sequentially, increasing overall ion flux by processing multiple ion species in parallel while maintaining compact dimensions
Solution Approach 2:
The patent employs periodic RF voltage modulation at specific frequencies to resonantly accelerate and transmit desired ion species while blocking others. The periodic nature of the RF fields creates time-gated transmission windows that enhance ion flux for targeted masses while maintaining compact electrode geometry
3Device complexity
If EDMA is used for mass analysis, then device size is reduced, but energy spread of ion beam increases
Solution Approach 1:
The patent designs the RF electrode system to perform multiple functions: mass selection through resonant excitation, energy filtering through selective acceleration, and beam focusing through electrodynamic confinement. This multi-functionality allows compact dimensions while maintaining narrow energy spread through coordinated control of RF parameters across different electrode pairs
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 generates a compact, high-yield mass analyzed ion beam with reduced energy dispersion, suitable for ion implantation applications, by effectively filtering unwanted ions and reducing energy spread through RF voltage manipulation.
Implementation Method 1
an electrodynamic mass analysis (EDMA) assembly, disposed downstream of the ion source. The EDMA assembly may include a first upper electrode, disposed above a beam axis; and a first lower electrode, disposed below the beam axis, opposite the first upper electrode, where the EDMA assembly is arranged to receive a first RF voltage signal at a first frequency
Implementation Method 2
a deflection assembly, disposed downstream to the EDMA assembly, the deflection assembly comprising a blocker, disposed along the beam axis
Implementation Method 3
an energy spread reducer (ESR), disposed downstream to the deflection assembly, the energy spread reducer arranged to receive a second RF voltage signal at a second frequency, twice the first frequency
Data Source
AI summary
An apparatus, including an electrodynamic mass analysis (EDMA) assembly. The EDMA assembly may include a first upper electrode, disposed above a beam axis; and a first lower electrode, disposed below the beam axis, opposite the first upper electrode, the EDMA assembly arranged to receive a first RF voltage signal at a first frequency. The apparatus may include a deflection assembly, disposed downstream to the EDMA assembly, the deflection assembly comprising a blocker, disposed along the beam axis. The apparatus may include an energy spread reducer (ESR), disposed downstream to the deflection assembly, the energy spread reducer arranged to receive a second RF voltage signal at a second frequency, twice the first frequency. The ESR may include an upper ESR electrode, disposed above the beam axis; and a lower ESR electrode, disposed below the beam axis.