Beam Line Protrusions Mitigate Neutral Particle Contamination
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Solution Overview
Problem
Ion implantation systems face significant challenges in reducing energy contamination due to scattered particles, particularly neutral particles that are not affected by deceleration processes, leading to undesired implantation depths and device performance issues.
Innovation Solution
The implementation of a beam line assembly with protrusions and grooves along the ion beam path, designed to vary in size, shape, and angle, which are positioned to impact and reflect neutral particles away from the workpiece, thereby reducing forward scattering and energy contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional charge exchange minimization methods are used, then energy contamination from charge exchange reactions is reduced, but energy contamination from forward scattered neutrals remains unaddressed
Solution Approach 1:
The beam tunnel wall is segmented into multiple protrusions with grooves, creating discrete scattering centers along the beam path. This segmentation allows targeted interception of forward scattered neutrals at different positions, addressing the limitation of traditional single-method EC reduction approaches.
Solution Approach 2:
The protrusions with grooves serve as intermediary structures between the ion beam and the workpiece. These intermediaries intercept and scatter forward scattered neutrals, preventing them from reaching the workpiece and causing energy contamination, thus adding a new mechanism to the traditional charge exchange minimization approach.
2Object-affected harmful factors
If the beam tunnel wall is smooth, then manufacturing is simple, but forward scattered neutrals can travel unimpeded to the workpiece
Solution Approach 1:
Instead of making the entire beam tunnel wall complex, only localized protrusions with grooves are added at specific positions where forward scattered neutrals are most problematic. This local quality modification effectively intercepts neutrals while keeping the overall structure relatively simple and manufacturable.
3Object-affected harmful factors
If uniform protrusions are used throughout the beam tunnel, then manufacturing is easier, but particle trajectory coverage is insufficient
Solution Approach 1:
The protrusions are configured with varying properties (size, shape, angle, groove spacing) at different positions along the beam tunnel, optimized to intercept neutrals from specific trajectory ranges. This local variation in protrusion characteristics provides comprehensive trajectory coverage while remaining manufacturable.
Solution Approach 2:
The geometric parameters of the protrusions (dimensions, angles, groove spacing) are varied along the beam tunnel to match the distribution of forward scattered neutral trajectories. This parameter optimization ensures effective neutral interception across different beam positions and angles.
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 effectively mitigates energy contamination by redirecting neutral particles within the beam line assembly before they reach the workpiece, ensuring more precise and controlled ion implantation, thereby enhancing semiconductor device performance.
Implementation Method 1
mitigate or remove the total number of forward scattered neutrals affecting a quality of implantation
Data Source
AI summary
Methods and apparatus for reducing energy contamination can be provided to a beam line assembly for ion implantation. Protrusions comprising surface areas and grooves therebetween can face neutral trajectories within a line of sight view from the workpiece within the beam line assembly. The protrusions can alter the course of the neutral trajectories away from the workpiece or cause alternate trajectories for further impacting before hitting a workpiece, and thereby, further reduce energy contamination for more sensitive implants.