Electrode Substrate Stack for Electron Beam Aberration Correction
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Solution Overview
Problem
Existing multiple electron beam irradiation apparatuses face challenges in expanding the field of view due to field curvature aberration, which leads to blurring of beam spots, and require multiple power sources for each beam, resulting in a complex apparatus configuration.
Innovation Solution
A multiple electron beam irradiation apparatus that uses a stack of electrode substrates with varying diameter openings to adjust the image plane conjugate position of each primary electron beam, allowing for correction of aberration and focusing without the need for individual power sources for each beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple electron beams are used to expand the field of view, then the inspection area increases, but field curvature aberration causes blurring of beam spots
Solution Approach 1:
The patent divides the beam correction function into multiple segments by stacking several electrode substrates (first, second, third electrode substrates) with different opening diameters. Each substrate segment handles a specific aspect of aberration correction, allowing the system to maintain beam focus across a larger field of view without blurring.
Solution Approach 2:
The patent applies different opening diameters to different electrode substrates based on their specific positions and functions in the beam path. The first electrode substrate has a first opening diameter, the second has a second opening diameter, and the third has a third opening diameter, where these diameters are specifically designed to correct field curvature aberration at different stages of beam propagation.
2Manufacturing precision
If individual power sources are used for each beam to correct aberration, then beam focusing accuracy improves, but apparatus complexity increases significantly
Solution Approach 1:
The patent merges multiple aberration correction functions into a single integrated electrode substrate assembly. Instead of using separate power sources and correction mechanisms for each beam, the stacked electrode substrates work together as one unified system that corrects field curvature aberration for all beams simultaneously, greatly reducing apparatus complexity.
Solution Approach 2:
The electrode substrates serve multiple functions: they act as both aperture stops that define beam paths and as electrostatic lenses that correct aberrations. By making the electrode substrates multi-functional, the patent eliminates the need for separate correction devices and power sources for each beam, simplifying the overall apparatus while maintaining focusing accuracy.
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 solution effectively corrects field curvature aberration, allowing for an expanded field of view and reducing the apparatus complexity by using a single power source for all beams, thereby improving the accuracy and efficiency of pattern inspection in semiconductor manufacturing.
Implementation Method 1
as the beam irradiating the surface of the target object comes away from the optical axis center to be toward the periphery, a difference arises in the beam spot diameter due to the effect of field curvature aberration
Implementation Method 2
acquires a secondary electron image of the pattern emitted by irradiation with multiple electron beams
Data Source
AI summary
A multiple electron beam irradiation apparatus includes a forming mechanism which forms multiple primary electron beams; a plurality of electrode substrates being stacked in each of which a plurality of openings of various diameter dimensions are formed, the plurality of openings being arranged at passage positions of the multiple primary electron beams, and through each of which a corresponding one of the multiple primary electron beams passes, the plurality of electrode substrates being able to adjust an image plane conjugate position of each of the multiple primary electron beams depending on a corresponding one of the various diameter dimensions; and a stage which is capable of mounting thereon a target object to be irradiated with the multiple primary electron beams having passed through the plurality of electrode substrates.