Ion Source Electron Gun Plasma Uniformity
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Solution Overview
Problem
Existing ion sources struggle to produce a uniform ion density profile along the longitudinal axis, especially when generating extended ribbon beams for larger substrates, due to space-charge loading and aberrations induced by beam transport optics, making it difficult to achieve uniform dose implantation across substrates.
Innovation Solution
The design incorporates multiple electron guns and a control circuit to form and sustain plasmas within an ionization chamber, with gas inlets along the longitudinal axis and extraction electrodes, allowing for precise control of ion density distribution through electron beam and gas flow management, and the use of magnetic field sources to confine the electron beam and plasma, ensuring uniform ion beam extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional ion sources are used to generate extended ribbon beams for larger substrates, then the beam length is increased, but the ion density uniformity along the longitudinal axis deteriorates due to space-charge loading and beam transport optics aberrations
Solution Approach 1:
The ion source is divided into multiple independent electron guns (e.g., three electron guns) arranged along the longitudinal axis, each capable of generating electrons independently. This segmentation allows separate control of electron emission from different regions, enabling compensation for space-charge effects and maintenance of uniform ion density over extended beam lengths.
Solution Approach 2:
Each electron gun region is optimized with local gas injection (through individual gas inlet lines) and independent electron emission control, creating locally tailored plasma conditions. This local quality approach ensures that each segment of the extended beam maintains optimal ionization and density characteristics, preventing uniformity degradation along the longitudinal axis.
2Manufacturing precision
If multiple electron guns and gas inlets are added to improve ion density uniformity, then the manufacturing complexity increases
Solution Approach 1:
Each electron gun assembly serves multiple functions: electron generation, local plasma formation, and ion source for a specific beam segment. The modular design allows each unit to be replicated and controlled independently, reducing overall system complexity through functional integration while achieving uniform ion density across the extended beam.
Solution Approach 2:
The system incorporates dynamic control capabilities where each electron gun and gas inlet can be independently adjusted during operation. This dynamic control allows real-time optimization of ion density uniformity and enables adaptation to different beam length requirements without physical reconfiguration.
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 enables the generation of a uniformly distributed ion beam along the longitudinal axis, effectively addressing the challenge of achieving uniformity in ion density profiles for extended ribbon beams, enhancing dose uniformity and implantation efficiency across larger substrates.
Implementation Method 1
an electron source for generating a beam of electrons
Implementation Method 2
The plasma region is adapted to form a plasma from the gas received via the inlet, and the plasma is sustained by at least a portion of the beam of electrons generated by the electron source
Implementation Method 3
the use of magnetic field sources to confine the electron beam and plasma
Implementation Method 4
The outlet is configured to deliver at least one of (i) ions generated by the plasma or (ii) at least a portion of the beam of electrons generated by the electron source
Data Source
AI summary
An ion source is provided that includes at least one electron gun. The electron gun includes an electron source for generating a beam of electrons and an inlet for receiving a gas. The electron gun also includes a plasma region defined by at least an anode and a ground element, where the plasma region can form a plasma from the gas received via the inlet. The plasma can be sustained by at least a portion of the beam of electrons. The electron gun further includes an outlet for delivering at least one of (i) ions generated by the plasma or (ii) at least a portion of the beam of electrons generated by the electron source.