Multi-Beam Trajectory Evaluation for SAA Angle Deviation Detection
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Solution Overview
Problem
The accuracy of multi-beam writing in semiconductor devices is compromised by SAA angle deviations caused by electrical charging of dust and contamination on aperture array substrates, which are difficult to detect and correct due to the complexity of the electrode structure and large number of microscopic openings, leading to distortion and aberration on the writing surface.
Innovation Solution
A multi-charged particle beam evaluation method that measures beam positions at multiple heights to identify and exclude beams with SAA angle deviations by calculating position differences and plotting singular changes, allowing for improved pattern writing accuracy and defect detection in the aperture array substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multi-beam writing apparatus is used to improve throughput, then productivity increases, but SAA angle deviations occur due to dust and contamination charging, reducing manufacturing precision
Solution Approach 1:
The patent performs preliminary measurement of beam positions at multiple heights before actual writing to detect SAA angle deviations. By measuring beam trajectories in advance and identifying affected beams, the system can correct or exclude problematic beams before they impact writing accuracy, thus resolving the contradiction between high throughput and manufacturing precision
Solution Approach 2:
The patent implements a feedback mechanism where beam positions are measured at multiple heights, position differences are calculated, and singular changes indicating SAA angle deviations are detected. This feedback loop allows the system to identify and correct beams with trajectory deviations, maintaining writing accuracy while preserving the high productivity benefits of multi-beam operation
2Productivity
If aperture array substrates with many microscopic openings are used to enable multi-beam operation, then productivity increases, but detection of dust and insulator exposure becomes extremely difficult
Solution Approach 1:
The patent introduces an intermediary measurement approach by using beam position measurements at multiple heights as a mediator to indirectly detect the presence and effect of dust and insulator exposure. Instead of directly inspecting the complex aperture array substrate, the method measures the impact of contaminants on beam trajectories, making defect detection feasible despite the substrate's complexity
Solution Approach 2:
The patent replaces direct mechanical/optical inspection of the aperture array substrate with a functional measurement approach. By measuring beam positions and calculating position differences, the system substitutes direct defect detection with indirect trajectory analysis, overcoming the difficulty of detecting defects in substrates with 260,000+ microscopic openings
3Ease of manufacture
If conventional inspection techniques for LSI are applied to aperture array substrates, then manufacturing processes remain simple, but the techniques are insufficient to detect local defects affecting beam trajectories
Solution Approach 1:
The patent transitions from conventional two-dimensional inspection to a three-dimensional measurement approach by measuring beam positions at multiple heights along the optical axis. This dimensional extension allows detection of SAA angle deviations that conventional planar inspection techniques cannot detect, improving defect detection capability while maintaining manufacturing simplicity
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 method enhances the accuracy of pattern writing by identifying and excluding beams with SAA angle deviations, improving the reliability of the multi-beam writing apparatus and facilitating efficient defect identification and quality improvement of the aperture array substrates.
Implementation Method 1
dust and/or contamination (dirt produced by beam irradiation) adhering to an SAA substrate may be charged to cause deflection
Implementation Method 2
cause deflection which is not expected according to an electron optical design, thus the trajectories of the beams in part of a multi-beam may be bent
Data Source
AI summary
In one embodiment, a multi charged particle beam evaluation method is for evaluating trajectories of a plurality of individual beams in a multi charged particle beam which has passed through a plurality of openings provided in an aperture array substrate. The method includes measuring positions of the plurality of individual beams at each of a plurality of heights, in an optical axis direction, of an imaging plane of the multi charged particle beam, or a measurement plane on which a mark for beam position measurement is formed, the plurality of heights being different from each other, and extracting a singular beam in which a beam trajectory has changed among the plurality of individual beams based on a position difference, the position difference being a difference between beam positions of the plurality of individual beams measured at each of the plurality of heights.