Ion Implantation Scan Uniformity via Interlaced Beam Shifting
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Solution Overview
Problem
Existing ion implantation methods result in poor uniformity of ion dose distribution due to overlapping scan lines during the implantation process, leading to larger values in the distribution variation function D(x), which affects the quality of the ion implantation process.
Innovation Solution
The ion beam is shifted with an interlace pitch in the direction perpendicular to the scan direction, ensuring that ion implantation scan lines at 0 orientation degree do not overlap with those at 180 orientation degree, and the substrate is rotated with specific interlace pitches to improve uniformity, allowing for parallel and interlaced scan lines that reduce the distribution variation function D(x).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the ion beam scans the substrate to form parallel ion implantation scan lines, then the ion implantation process can be completed, but the scan lines overlap causing poor uniformity of ion dose distribution
Solution Approach 1:
The patent applies asymmetry by shifting the ion beam with an interlace pitch that is specifically designed to prevent overlap between scan lines at different orientation degrees. The shift amount is calculated based on the scan pitch and substrate rotation angles, creating an asymmetric positioning strategy that eliminates the overlapping problem while maintaining complete substrate coverage.
Solution Approach 2:
The patent introduces a dimensional solution by combining substrate rotation in the angular dimension with ion beam shifting in the spatial dimension. By rotating the substrate to different orientation degrees (0°, 60°, 120°, 180°, 240°, 300°) and applying corresponding interlace pitch shifts, the method transforms a one-dimensional scan line overlap problem into a multi-dimensional non-overlapping pattern.
2Manufacturing precision
If the substrate is rotated and ion beam is shifted with interlace pitch, then the uniformity of ion dose distribution is improved, but the complexity of the implantation process increases
Solution Approach 1:
The patent employs periodic action by dividing the substrate implantation into multiple periodic stages, each corresponding to a specific substrate orientation degree (0°, 60°, 120°, 180°, 240°, 300°). Each period involves a complete scan pass with a specific interlace pitch shift, creating a repetitive yet progressive pattern that systematically covers the entire substrate while maintaining uniformity.
Solution Approach 2:
The patent segments the ion implantation process into six distinct implantation groups, each corresponding to a specific substrate orientation degree. This segmentation allows the complex task of covering the entire substrate with uniform dose distribution to be broken down into manageable, repeatable units, each contributing to the overall uniformity without causing overlap.
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 uniformity of the ion dose distribution by reducing the value of the distribution variation function D(x), thereby improving the overall quality of the ion implantation process.
Implementation Method 1
An ion beam scans a substrate S along a scan path to implant ions onto the substrate surface and forms a plurality of parallel ion implantation scan lines on the surface of the substrate S
Data Source
AI summary
An ion implantation method is provided. The method, before ion implanting, is to rotate the substrate by an angle and shift the scan path of the ion beam with an interlace pitch in the direction perpendicular to the scan direction and on the plane of the substrate. Therefore a plurality of interlaced and not overlapped ion implantation scan lines are formed on the surface of the substrate, so the method can enhance the uniformity of the dose of the ion implantation in the substrate.