Ion Beam Scanning Control for Implantation Uniformity
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Solution Overview
Problem
Conventional ion beam scanner calibration techniques are inadequate for wide or variable ion beams, leading to non-uniform implantation and prolonged calibration times, especially with low energy ion beams experiencing space charge expansion.
Innovation Solution
A method involving dynamic beam profile measurement and calculation of a corrected scan rate to produce a corrected ribbon ion beam, reducing flux variations and accelerating the calibration process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If point-to-point scanner calibration techniques are used, then beam flux can be measured at discrete points, but uniform implantation cannot be achieved for wide or variable beams and calibration time is excessively long
Solution Approach 1:
The patent replaces the mechanical point-to-point measurement system with an optical imaging system. A camera captures the entire beam profile simultaneously, substituting sequential mechanical sensor movements with parallel optical detection. This enables full beam characterization in a single snapshot, reducing calibration time from minutes to seconds while providing comprehensive spatial information for achieving uniform implantation across wide beams.
Solution Approach 2:
The patent transitions from one-dimensional point-by-point measurement to two-dimensional spatial mapping. By capturing the complete beam profile across the scan direction in a single measurement, the system adds the spatial dimension of simultaneous multi-point detection, enabling comprehensive beam characterization without the time penalty of sequential measurements.
2Measurement precision
If point-to-point measurements are taken over multiple beam passes, then sufficient data can be obtained for calibration, but processing throughput is significantly reduced
Solution Approach 1:
The patent enables continuous beam profiling by capturing the entire beam profile in a single continuous action rather than requiring multiple discrete beam passes. The imaging system continuously monitors the beam during scanning, maintaining useful measurement action throughout the scan process and eliminating idle time between sequential measurements, thereby preserving processing throughput.
Solution Approach 2:
The patent performs preliminary characterization of the entire beam profile in advance during the scan setup phase. By capturing the complete spatial distribution of beam flux beforehand, the system establishes accurate beam models that can be used for subsequent processing without requiring repeated measurement passes, thus maintaining high productivity.
3Device complexity
If conventional calibration techniques assume point beam or constant beam profile, then calibration can be performed simply, but non-uniformity occurs with wide beams or beams with space charge expansion
Solution Approach 1:
The patent applies local quality by measuring and characterizing the beam profile at multiple spatial locations simultaneously across the scan direction. Instead of assuming uniform beam properties, the imaging system captures local variations in beam width and flux density at different positions, enabling position-specific calibration corrections that account for space charge expansion and other local beam effects.
Solution Approach 2:
The patent introduces dynamics by capturing the beam profile during actual scanning motion rather than assuming static beam characteristics. The system measures how the beam profile evolves dynamically across the scan, accounting for variations in beam width and shape at different scan positions, which enables accurate correction for dynamic beam effects like space charge expansion.
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
Facilitates uniform ion implantation with significantly reduced calibration time, improving processing throughput by accounting for beam variations and space charge effects.
Implementation Method 1
an ion beam is scanned at a scan rate to make a ribbon beam
Implementation Method 2
the scanned beam flux is measured at the point
Implementation Method 3
low energy ion beams that experience space charge expansion (e.g., lateral divergence in the scan or X direction)
Data Source
AI summary
One embodiment of the invention relates to a method for adjusting the ribbon beam flux of a scanned ion beam. In this method, an ion beam is scanned at a scan rate, and a plurality of dynamic beam profiles are measured as the ion beam is scanned. A corrected scan rate is calculated based on the plurality of measured dynamic beam profiles of the scanned beam. The ion beam is scanned at the corrected scan rate to produce a corrected ribbon ion beam. Other methods and systems are also disclosed.