Integrated Quadrupole Ion Stripping for Beam Trajectory Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ion implantation systems face challenges in achieving high beam currents and controlling ion trajectory scattering during charge stripping, particularly when dealing with high charge state ions, which typically result in lower beam currents and uncontrollable scattering.
Innovation Solution
A charge stripping system with a stripper tube and focusing apparatus, such as quadrupoles or solenoids, is used to control ion trajectories and mitigate scattering by refocusing ions as they pass through the stripper tube, allowing for the conversion of low-charge state ions to higher charge states with increased beam currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If charge stripping is performed to increase ion charge state, then beam current increases, but ion trajectory scattering becomes uncontrollable
Solution Approach 1:
A gas stripper is introduced as an intermediary medium between the ion source and the quadrupole lenses. The gas stripper performs charge state conversion by having ions pass through a controlled gas target, converting low charge state ions to high charge state ions. This mediator enables beam current enhancement while the subsequent quadrupole lenses compensate for the scattering effect, resolving the contradiction between increased productivity and maintained trajectory precision.
Solution Approach 2:
The system changes the charge state parameter of ions by passing them through a gas stripper with controlled gas pressure and composition. By adjusting gas pressure, gas type, and stripper length, the charge state conversion efficiency is optimized to increase beam current while controlling the degree of scattering, thus balancing productivity improvement with trajectory control.
2Manufacturing precision
If quadrupole lenses are added to control ion scattering, then trajectory control improves, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical adjustment mechanisms with electrically controllable quadrupole lenses. The quadrupole lenses use electric fields to provide dynamic focusing and steering of ion beams, allowing precise trajectory control without mechanical moving parts. This substitution reduces mechanical complexity while maintaining or improving trajectory control precision.
3Productivity
If gas pressure in stripper is increased to enhance charge stripping efficiency, then beam current increases, but ion scattering increases
Solution Approach 1:
The system optimizes gas pressure as a controllable parameter in the gas stripper. By carefully selecting and adjusting the gas pressure, the charge stripping efficiency is maximized to increase beam current while the scattering effect is kept within acceptable limits. The quadrupole lenses then compensate for the controlled amount of scattering, achieving a balance where productivity improvement does not come at the cost of trajectory precision.
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 enhances ion beam current and maintains controlled ion trajectories, achieving higher beam currents and purer energy spectra by efficiently stripping electrons and refocusing ions, thereby improving the ion implantation process.
Implementation Method 1
The plurality of quadrupoles can comprise at least two electrostatic quadrupoles or at least two magnetic quadrupoles
Implementation Method 2
a charge stripper is positioned within a charge stripper housing between the first accelerator and the second accelerator along the beam path of the ion beam
Data Source
AI summary
An ion implantation system has a first linear accelerator for accelerating ions of an ion beam to a first energy along a beam path. A second linear accelerator positioned downstream of the first linear accelerator along the beam path accelerates the ions to a second energy. A charge stripper has a stripper tube with a passageway positioned between the first and second linear accelerators. A charge stripping medium is provided in the passageway to strip at least one electron from the ions as the ion beam passes through the charge stripping medium. A focusing apparatus is associated with the stripper tube to control a trajectory of the ions within the passageway of the stripper tube. The focusing apparatus can be two or more quadrupoles and include an electrostatic lens, a magnet, a solenoid, or a Einzel lens.