Beam Complementary Aperture for Ion Implantation Contamination Reduction
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Solution Overview
Problem
Traditional ion implantation systems suffer from contamination and particle issues due to mismatched beam defining aperture shapes and ion beam shapes, leading to uneven beam intercept and increased contamination.
Innovation Solution
The implementation of a beam complementary aperture that matches the cross-sectional envelope of the ion beam, positioned downstream of the mass analyzer, to reduce particles and contamination by ensuring a precise fit with the ion beam shape, thereby minimizing beam clipping and particle transport to the target chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional rectangular resolving apertures are used in ion implantation systems, then mass resolution is achieved, but beam clipping occurs and contamination increases
Solution Approach 1:
The patent applies asymmetry by changing the aperture shape from a traditional rectangular form to a custom-shaped aperture that matches the asymmetric profile of the ion beam envelope. This custom shape is specifically designed to conform to the beam's actual distribution, eliminating unnecessary clipping of the beam edges while preserving mass resolution capabilities.
Solution Approach 2:
The patent implements local quality by creating an aperture with non-uniform opening dimensions that vary across its surface. The aperture opening is locally adjusted to match the local beam intensity distribution, providing optimal transmission in regions where the beam is present and blocking in regions where it is absent, thereby reducing contamination without sacrificing mass resolution.
2Shape
If additional beam forming and shaping apertures are added upstream or downstream of the resolving aperture, then beam size is defined, but device complexity increases
Solution Approach 1:
The patent merges the functions of beam forming, shaping, and mass resolution into a single integrated custom-shaped aperture. This consolidation eliminates the need for separate upstream and downstream beam forming apertures, reducing the total number of components while achieving both precise beam size definition and mass resolution in one element.
Solution Approach 2:
The custom-shaped aperture serves multiple functions simultaneously: it acts as a mass resolving aperture, a beam forming aperture, and a beam shaping aperture. This multi-functionality reduces device complexity by replacing what would traditionally require multiple separate components with a single versatile aperture design.
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 solution effectively reduces contamination and particle transport, improving process throughput and minimizing sputtered material generation, while maintaining sufficient mass resolution and beam current.
Implementation Method 1
The mass selectivity is accomplished with the use of electromagnets to bend the charged ion beam and then pass the beam through a mass selection resolving aperture.
Data Source
AI summary
An ion implantation system comprising an ion source configured to generate an ion beam along a beam path, a mass analyzer is located downstream of the ion source wherein the mass analyzer is configured to perform mass analysis of the ion beam and a beam complementary aperture located downstream of the mass analyzer and along the beam path, the beam complementary aperture having a size and shape corresponding to a cross-sectional beam envelope of the ion beam.