High-Energy Ion Implanter Beam Divergence Control
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Solution Overview
Problem
High-energy ion implanters face challenges with beam divergence and energy spread, leading to reduced precision and increased contamination, particularly in high-energy ion implantation processes, where precise angle and depth control are critical for semiconductor device production.
Innovation Solution
A high-energy ion implanter with a U-shaped beamline configuration using electrostatic parallelizing lenses and energy filters, combined with horizontal focusing elements, to suppress beam divergence and maintain high vacuum conditions, ensuring precise ion implantation and improved productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-energy ion implantation is performed to improve semiconductor device performance and resolution, then implantation depth and sensitivity are improved, but beam divergence and energy spread increase, reducing implantation precision
Solution Approach 1:
The beamline is divided into multiple vacuum chambers (acceleration chamber, deflection chamber, implantation chamber) separated by vacuum gates. This segmentation allows independent optimization of each section while maintaining overall vacuum integrity, enabling precise beam control despite high energy
Solution Approach 2:
Electrostatic lenses and deflectors are introduced as intermediary elements to control and focus the ion beam. These components act as mediators between the ion source and substrate, correcting beam divergence and maintaining precise implantation angles even at high energies
2Productivity
If batch treatment type ion implantation is used to increase productivity, then multiple wafers are processed simultaneously, but implantation angle deviation occurs due to wafer rotation and centrifugal force
Solution Approach 1:
Instead of rotating the wafers (batch treatment approach), the patent uses a stationary wafer stage with a scanning beam (single wafer approach). This inversion of the conventional approach eliminates centrifugal force effects and angle deviations while maintaining productivity through beam scanning
Solution Approach 2:
The mechanical wafer rotation system is replaced with an electrostatic beam scanning system. The electrostatic deflectors control beam position and angle without mechanical movement of the wafer, eliminating angle deviations caused by centrifugal force
3Manufacturing precision
If single wafer type ion implanter is used to improve implantation angle precision, then angle uniformity is improved, but beam divergence reduces productivity
Solution Approach 1:
The beam scanning system operates continuously across the wafer surface without interruption. The electrostatic deflectors enable smooth, continuous beam movement and positioning, maintaining both precision and productivity through uninterrupted implantation process
Solution Approach 2:
The system dynamically adjusts electrostatic field parameters (voltage, polarity, magnitude) to control beam position and focus. By changing these parameters in real-time during scanning, the system maintains precise angle control while covering the entire wafer surface efficiently
4Object-affected harmful factors
If photoresist is thickened to cover non-implantation regions in high-energy implantation, then contamination is prevented, but implantation depth control becomes more difficult
Solution Approach 1:
The photoresist layer is applied with locally optimized thickness: thicker in non-implantation regions for contamination protection, and thinner or removed in implantation regions for precise depth control. This local differentiation resolves the contradiction between protection and precision
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 solution effectively reduces beam divergence, enhances energy precision, and maintains high vacuum conditions, resulting in improved ion implantation accuracy and productivity, suitable for high-energy semiconductor applications.
Implementation Method 1
electrostatic parallelizing lens
Implementation Method 2
electrostatic final energy filter for high-energy beam
Implementation Method 3
deflection electromagnets
Implementation Method 4
horizontal focusing element
Implementation Method 5
ion source
Implementation Method 6
mass analyzer
Implementation Method 7
radio frequency linear accelerator
Data Source
AI summary
A high-energy ion implanter includes: a beam generation unit that includes an ion source and a mass analyzer; a high-energy multi-stage linear acceleration unit that accelerates an ion beam so as to generate a high-energy ion beam; a high-energy beam deflection unit that changes the direction of the high-energy ion beam toward the wafer; and a beam transportation unit that transports the deflected high-energy ion beam to the wafer. The deflection unit is configured by a plurality of deflection electromagnets, and at least a horizontal focusing element is inserted between the plurality of deflection electromagnets.