Angled Graphite Beamline Surfaces to Prevent Low-Energy Ion Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor processing, low energy ion beams cause thin films to form on beamline components, leading to film delamination and contamination of workpieces due to low sputter yields and thermal cycling, which is exacerbated by boron and carbon atoms coating surfaces at low energies.
Innovation Solution
Modifying the surfaces of beamline components with a predetermined angle of incidence to increase the sputter yield, such as through texturing with V-shaped grooves or angled features, to enhance film removal and prevent deposition, particularly for boron and carbon ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If low energy ion beams are used for implantation, then implantation precision is improved, but film deposition increases due to low sputter yield
Solution Approach 1:
The beamline component surface is modified with localized V-shaped grooves or angled features that create specific incidence angle zones. These local geometric modifications cause the ion beam to strike at angles greater than 15 degrees, increasing the sputter yield locally at the beam impact region while maintaining the overall low energy implantation process precision.
Solution Approach 2:
The surface geometry parameters of the beamline component are changed by introducing V-shaped grooves or angled features. This modifies the ion beam incidence angle parameter from near-normal to greater than 15 degrees, which changes the sputter yield parameter from low to enhanced, thereby reducing net film deposition while preserving implantation precision.
2Productivity
If beamline components are continuously exposed to low energy ion beams, then processing productivity is improved, but film delamination and particle contamination increase
Solution Approach 1:
The beamline component surface is pre-modified with V-shaped grooves or angled features before ion beam exposure. This preliminary geometric modification ensures that subsequent low energy ion beam exposure will result in enhanced sputter yield and reduced film accumulation, preventing film delamination and particle contamination before they can occur during continuous processing operations.
Solution Approach 2:
The ion beam, which initially causes harmful film deposition at low energies, is redirected through geometric modification to strike at angles that convert this harmful deposition effect into a beneficial cleaning effect through enhanced sputter yield. The same ion beam that causes the problem becomes the solution by self-cleaning the surface through angled incidence.
3Ease of manufacture
If conventional smooth surfaces are used, then manufacturing simplicity is improved, but particle generation increases due to film delamination
Solution Approach 1:
Rather than modifying the entire beamline component surface, only the specific regions exposed to the ion beam are modified with V-shaped grooves or angled features. This localized modification approach maintains manufacturing simplicity for the overall component while creating the necessary geometric features in the beam impact zone to prevent film delamination and reduce particle generation.
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 modified surfaces achieve a sputter yield greater than one, effectively preventing film deposition and extending the lifetime of beamline components by reducing particle contamination and film delamination.
Implementation Method 1
the sputter yield of incoming ions (e.g., the number of atoms ejected from the film for each incoming ion) is significantly less than 1.0
Data Source
AI summary
An ion source for an ion implantation system is configured to form an ion beam from a predetermined species along a beamline, where the ion beam is at an initial energy. A deceleration component is configured to decelerate the ion beam to a final energy that is less than the initial energy. A workpiece support is configured to support a workpiece along a workpiece plane downstream of the deceleration component along the beamline. A beamline component is positioned downstream of the deceleration component along the beamline. The beamline component has a feature that is at least partially impinged by the ion beam, and where the feature has a surface having a predetermined angle of incidence with respect to the ion beam. The predetermined angle of incidence provides a predetermined sputter yield of the ion beam at the final energy that mitigates deposition of the ion species on the beamline component.