Inclined Aperture Array Layout for Non-Overlapping Multi-Beam Scans
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Solution Overview
Problem
Current charged particle beam technologies face challenges in generating multi-beams with high packing density and non-overlapping, parallel scan lines, leading to inefficiencies in processing speed and defect detection during semiconductor manufacturing.
Innovation Solution
The use of aperture arrays with specific arrangements of apertures, such as inclined and spaced apertures in a hexagonal pattern, to generate a multi-beam with a high packing density of sub-beams, allowing for continuous and overlapping scans that produce non-overlapping, parallel scan lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single charged particle beam is used to illuminate the aperture array, then the device complexity is reduced, but the productivity decreases due to sequential scanning requirements
Solution Approach 1:
The aperture array segments the single illuminating beam into multiple sub-beams, each traversing different portions of the sample simultaneously. This segmentation enables parallel processing of multiple scan lines, thereby increasing productivity while maintaining a relatively simple single-beam illumination system.
Solution Approach 2:
The patent transforms the temporal dimension of sequential scanning into a spatial dimension by arranging apertures in parallel rows. Multiple sub-beams scan different spatial regions simultaneously, converting a time-dependent process into a space-parallel process, thus improving processing speed without complicating the beam generation system.
2Manufacturing precision
If apertures are arranged in parallel rows orthogonal to the scanning direction, then the manufacturing precision of scan line spacing is improved, but the productivity decreases due to overlapping scan lines
Solution Approach 1:
The patent introduces asymmetry by inclining the aperture rows at an angle θ relative to the scanning direction. This asymmetric arrangement causes the scan lines to be spaced equally and remain non-overlapping, resolving the contradiction between precise spacing and effective throughput by optimizing the geometric configuration.
Solution Approach 2:
The patent changes the geometric parameter of aperture row orientation from orthogonal (0°) to an inclined angle θ. This parameter change transforms the scan line pattern from overlapping to non-overlapping while maintaining equal spacing, thereby improving productivity without sacrificing spacing precision.
3Productivity
If the aperture array generates a large number of sub-beams, then the productivity increases through parallel scanning, but the manufacturing precision of aperture placement becomes more difficult
Solution Approach 1:
The aperture array is segmented into multiple parallel rows, each containing a manageable number of apertures. This segmentation approach allows for easier manufacturing and positioning of individual rows while maintaining the overall high sub-beam count, thus achieving high productivity without excessive manufacturing complexity.
Solution Approach 2:
The patent employs a universal aperture design where all apertures share the same geometric parameters and spacing rules, regardless of their position in the array. This universality simplifies manufacturing by standardizing aperture fabrication and placement procedures, making it easier to achieve high positioning accuracy across a large number of sub-beams.
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 significantly reduces processing time and improves defect detection efficiency by enabling continuous scanning with equally spaced, non-overlapping scan lines, enhancing the throughput and yield in semiconductor manufacturing.
Implementation Method 1
A surface of an aperture array may be illuminated by a single charged particle beam. Each of the plurality of apertures in the aperture array may define a sub-beam that is emitted in a multi-beam from the aperture array.
Data Source
AI summary
Disclosed herein is an aperture array configured to define sub-beams that are scanned in a scanning direction in a charged particle apparatus, the aperture array comprising a plurality of apertures arranged in an aperture pattern that comprises: a plurality of parallel aperture rows, wherein apertures are arranged along the aperture rows and the aperture rows are inclined relative to the scanning direction; an edge aperture row defining an edge of the aperture pattern; and an adjacent aperture row adjacent the edge row; wherein the edge aperture row and the adjacent aperture row each comprise fewer apertures than another aperture row of the aperture pattern.