Plasma Generator Non-Metallic Components Ion Beam Purity
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Solution Overview
Problem
Traditional ion implanters face challenges in producing uniform ion density profiles and are contaminated by metallic ions, which affect the yield of semiconductor devices, particularly due to the use of refractory metal components in ion sources and plasma electron floods.
Innovation Solution
The development of plasma generators with components made from non-metallic materials such as silicon carbide, silicon nitride, graphite, and boron, which minimize metal contamination and improve ion beam uniformity by eliminating metallic exposure to the plasma, while maintaining refractory properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refractory metal components are used in ion sources and plasma electron floods, then structural strength and refractory properties are maintained, but metal contamination in ion beams and electron fluxes increases
Solution Approach 1:
The patent removes metallic materials from components that are exposed to plasma (ion source chamber walls, plasma electron flood chamber walls, electrode surfaces), extracting the harmful metallic elements from the plasma generation environment while maintaining structural integrity through alternative non-metallic materials
Solution Approach 2:
The patent changes the material parameter from metallic to non-metallic (such as ceramic coatings or non-metallic composite materials) for plasma-exposed components, fundamentally altering the chemical composition to eliminate metal contamination while preserving the required mechanical and thermal properties
2Device complexity
If conventional ion sources with metallic components are used, then device complexity is reduced, but ion beam uniformity and metal contamination control deteriorate
Solution Approach 1:
The patent extracts metallic materials from plasma-exposed components, replacing them with non-metallic alternatives that prevent metal contamination and improve ion beam uniformity without significantly increasing device complexity
Solution Approach 2:
The patent employs non-metallic composite materials (such as ceramic coatings or non-metallic composites) on ion source and plasma electron flood components, combining the benefits of low contamination with maintained structural and thermal properties
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 significantly reduces metal contamination in ion beams and electron fluxes, enhancing the yield and quality of semiconductor devices by ensuring a more uniform ion distribution and minimizing the impact of refractory metal contaminants.
Implementation Method 1
an electron beam adapted to travel in a first direction into the ionization chamber and form a primary plasma by electron impact ionization of a gas within the ionization chamber
Implementation Method 2
The cathode is heated by electron bombardment to a temperature sufficient to cause thermionic emission of electrons
Implementation Method 3
thermionic emission of electrons from the cathode in response to the heating
Data Source
AI summary
A plasma generator for an ion implanter is provided. The plasma generator includes an ionization chamber for forming a plasma that is adapted to generate a plurality of ions and a plurality of electrons. An interior surface of the ionization chamber is exposed to the plasma and constructed from a first non-metallic material. The plasma generator also includes a thermionic emitter including at least one surface exposed to the plasma. The thermionic emitter is constructed from a second non-metallic material. The plasma generator further includes an exit aperture for extracting at least one of the plurality of ions or the plurality of electrons from the ionization chamber to form at least one of an ion beam or an electron flux. The ion beam or the electron flux comprises substantially no metal. The first and second non-metallic materials can be the same or different from each other.