Multi-Beam Voltage Contrast Imaging Without Mode Switching
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Solution Overview
Problem
Existing corpuscular beam microscopes face challenges in achieving high-resolution voltage contrast imaging with minimal charging effects, particularly in semiconductor structures, due to limitations in aperture angle, lens aberrations, and the need for time-consuming two-stage processes that involve switching modes and potential hysteresis issues.
Innovation Solution
A method and apparatus using a corpuscular multi-beam microscope with a predefined aperture plate that allows simultaneous, targeted charging and high-resolution voltage contrast imaging by employing a grid arrangement of corpuscular beams with varying aperture sizes and currents, enabling localized and differential charging without mode switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high corpuscular currents are used for charging semiconductor structures, then charging efficiency is improved, but imaging resolution deteriorates due to lens aberrations
Solution Approach 1:
The patent divides the corpuscular beam into multiple individual beams arranged in a grid pattern. Each beam can be independently controlled to charge specific regions of the semiconductor structure. This segmentation allows the system to achieve high charging efficiency by activating multiple beams simultaneously while maintaining high resolution by keeping individual beam currents low enough to avoid significant lens aberrations.
Solution Approach 2:
The patent implements local quality by enabling different regions of the semiconductor structure to receive different corpuscular beam currents. The aperture plate allows selective activation of individual beams or beam groups, so that high current can be applied to regions requiring efficient charging while low current is used in regions where high resolution imaging is the priority, thus resolving the contradiction between charging efficiency and imaging resolution.
2Productivity
If aperture angle is increased to improve charging speed, then productivity is improved, but imaging precision deteriorates due to increased lens aberrations
Solution Approach 1:
The aperture plate creates multiple discrete beam paths with different aperture angles. Individual beams or beam groups can be selected to have larger aperture angles for faster charging of specific regions, while other beams maintain smaller aperture angles for high-resolution imaging, thus resolving the contradiction between charging speed and imaging precision through spatial segmentation of beam parameters.
3Reliability
If two-stage process with mode switching is used, then charging and imaging can be performed, but time consumption increases and hysteresis issues occur
Solution Approach 1:
The patent merges the charging function and imaging function into a single operational mode by using a corpuscular multi-beam microscope where multiple beams simultaneously perform both charging and imaging tasks. The aperture plate enables different beams to have different functions (some for charging, some for imaging) while operating in the same microscope mode, eliminating the need for mode switching and associated time losses and hysteresis issues.
Solution Approach 2:
The patent achieves continuity of useful action by enabling simultaneous charging and imaging operations through the multi-beam system. While some beams are charging the semiconductor structure, other beams are simultaneously performing imaging, thus eliminating the sequential two-stage process and its associated time losses. The useful actions of charging and imaging continue concurrently without interruption.
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
Enables high-resolution voltage contrast imaging with reduced charging effects, improved throughput, and accurate detection of defects in semiconductor structures, including small lateral inaccuracies, without the need for precharging modes, thus enhancing process monitoring and defect detection efficiency.
Implementation Method 1
reflected corpuscular particles or secondary emissions such as secondary electrons or photons are detected
Data Source
AI summary
A method for voltage contrast imaging, for example on a semiconductor sample, uses a corpuscular multi-beam microscope with a multiplicity of individual corpuscular beams in a grid arrangement. The method includes sweeping the multiplicity of individual corpuscular beams over a sample having at least one electrically chargeable structure, and charging the sample with a first quantity of first corpuscular beams of the corpuscular multi-beam microscope. The method also includes determining a voltage contrast at the at least one electrically chargeable structure of the sample with a second quantity of second corpuscular beams of the corpuscular multi-beam microscope.