Spot Beam Ion Implantation Alignment for Non-Uniform Dose Patterns
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Solution Overview
Problem
Existing spot beam ion implantation systems face challenges in achieving a desired non-uniform ion implantation pattern due to non-uniformity in ion distribution and irregular beam shapes, leading to unintended variations and material waste.
Innovation Solution
A method and system that utilizes a system controller to analyze a target pattern, align it with the spot beam profile and scan direction, optimize beam properties, and adjust the workpiece orientation to achieve precise non-uniform implantation by rotating and transposing patterns, calculating optimal beam sizes, and selecting a spot beam recipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a spot beam is scanned across a workpiece to achieve non-uniform ion implantation, then targeted implantation patterns can be produced, but non-uniformity in ion distribution occurs due to scanner imperfections causing beam height shrinkage and centroid shifts
Solution Approach 1:
The system performs preliminary characterization of the spot beam properties at multiple scan positions before actual implantation. Beam height, centroid position, and other parameters are measured and stored in advance, then used to calculate compensation factors that correct for scanner-induced non-uniformities during the implantation process
Solution Approach 2:
The system implements a feedback mechanism where beam profiler measurements taken during scanning are used to dynamically adjust implantation parameters. The measured beam properties feed back into the control system, which modifies the implantation dose distribution to compensate for observed deviations from the ideal beam profile
2Ease of manufacture
If a spot beam with fixed cross-sectional shape is used for implantation, then the beam can be easily generated and scanned, but the beam shape does not match desired non-uniform implantation patterns requiring thin horizontal lines
Solution Approach 1:
The system dynamically adjusts beam parameters including effective spot size and shape by modifying extraction aperture dimensions, acceleration voltage, and beam energy during scanning. This allows the beam to adapt its cross-sectional characteristics to match the desired implantation pattern while maintaining ease of generation through standard ion source operation
Solution Approach 2:
The system changes multiple beam parameters simultaneously - extraction aperture size, acceleration voltage, and beam energy - to transform the spot beam cross-sectional shape. These parameter changes enable the beam to conform to thin horizontal line patterns or other non-uniform distributions while keeping the ion source configuration simple
3Manufacturing precision
If the spot beam height is significantly smaller than the workpiece width, then precise localized implantation is achieved, but extensive scanning is required increasing processing time and reducing throughput
Solution Approach 1:
The system segments the implantation process into multiple passes with different beam parameters. Instead of scanning a small beam across the entire workpiece width in one continuous operation, the workpiece is divided into zones that are implanted in sequence, with beam parameters optimized for each zone to reduce total scanning time
Solution Approach 2:
The system introduces temporal dimensionality by varying beam parameters dynamically during the scanning process. Beam energy, aperture size, and other parameters are modulated as functions of scan position, allowing the effective beam width to expand when crossing broad regions of the workpiece while maintaining precision in localized areas
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 enhances the fidelity of the implantation process, reduces material waste, and increases throughput by minimizing downtime and setup errors.
Implementation Method 1
A spot beam may be projected through an electrostatic scanner adapted to controllably deflect the spot beam at varying angles in a first direction
Implementation Method 2
an ion source may be used to generate ions that are used in semiconductor manufacturing processes
Data Source
AI summary
A method of producing a non-uniform ion implant in a workpiece, including storing a target pattern as a target pattern array, analyzing the target pattern to identify maximal gradients, rotating the target pattern and the workpiece to align with a spot beam profile and a scan direction, and transposing the target pattern to a process array. The method further includes optimizing the process array, calculating a largest possible beam spot size, selecting a corresponding spot beam recipe, performing a test scan to determine a beam sweep angle of the spot beam, and rotating the target pattern, the process array, and the workpiece to account for the beam sweep angle. The method further incudes generating a predicted process dose pattern and comparing it to the target pattern, and calculating at least one measure of error representing a fidelity of the predicted process dose pattern to the target pattern.