Modular Electrode Design for Ion Beam Contamination Control
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Solution Overview
Problem
In beamline ion implanters, titanium electrodes sputter and contaminate substrates during ion beam acceleration, leading to unwanted titanium species being implanted alongside the target ions, which is problematic for semiconductor fabrication due to the generation of contaminant species and radiation.
Innovation Solution
The use of a modular electrode design with a reversible and detachable structure, where the insert, frame, and outer portion are made of different electrically conductive materials, specifically choosing materials like graphite, aluminum, or tungsten for the insert to minimize contamination and radiation, and high thermal conductivity materials for the frame to manage heat effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If titanium electrodes are used in the acceleration column, then the electrode provides good machinability and structural stability, but titanium sputtering occurs causing substrate contamination
Solution Approach 1:
The electrode is divided into multiple segments: an inner insert portion made of non-titanium material (such as aluminum, copper, or tungsten) and an outer frame portion made of titanium. This segmentation allows the beam-path surface to be made of contamination-free material while the structural portions can be titanium, resolving the contradiction between structural stability and substrate contamination.
Solution Approach 2:
Different portions of the electrode are made of different materials with different properties. The inner insert portion that contacts the ion beam is made of material with low sputtering rate (aluminum, copper, or tungsten), while the outer frame portion provides structural support and can be made of titanium. This local differentiation of material properties eliminates contamination at the beam-path surface while maintaining overall electrode reliability.
2Object-affected harmful factors
If a non-titanium material is used for the electrode, then substrate contamination is reduced, but thermal management and mechanical properties may deteriorate
Solution Approach 1:
The electrode is segmented into an inner insert portion for beam interaction and an outer frame portion for structural support and thermal management. The inner portion uses materials like aluminum or copper with high thermal conductivity for effective heat dissipation, while the outer titanium frame provides structural stability. This segmentation resolves both contamination and thermal management requirements.
Solution Approach 2:
The electrode employs a composite structure combining different materials: the inner insert may be made of aluminum, copper, or tungsten, while the outer frame is made of titanium. This composite construction allows optimization of each portion for its specific function - beam interaction and thermal management for the inner portion, and structural support for the outer portion - thereby resolving the contradiction between reducing contamination and maintaining thermal properties.
3Object-affected harmful factors
If a modular electrode design with multiple materials is used, then contamination and thermal management are improved, but device complexity increases
Solution Approach 1:
The electrode is divided into two main segments - an inner insert portion and an outer frame portion - that can be assembled together. This segmentation into a manageable number of components reduces complexity compared to more elaborate multi-material designs, while still achieving the goals of reducing contamination and improving thermal management. The simple two-part structure balances performance improvement with manufacturing complexity.
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 design reduces titanium contamination and unwanted radiation, providing a flexible and efficient means to manage ion beam energy and minimize substrate contamination across a wide range of ion energies, from 50 keV to 10 MeV, while allowing for easy maintenance and material selection based on application-specific requirements.
Implementation Method 1
an insert having an ion beam aperture to conduct the ion beam therethrough
Implementation Method 2
the insert, the frame, and the outer portion are electrically conductive
Implementation Method 3
high thermal conductivity materials for the frame to manage heat effectively
Data Source
AI summary
An electrode for manipulating an ion beam. The electrode may include an insert having an ion beam aperture to conduct the ion beam therethrough, the insert comprising a first electrically conductive material; a frame disposed around the insert and comprising a second electrically conductive material; and an outer portion, the outer portion disposed around the frame and comprising a third electrically conductive material, wherein the insert is reversibly detachable from the frame, and wherein the frame is reversibly attachable from the outer portion.