Multi Charged Particle Beam Evaluation for Dose Distribution Accuracy
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Solution Overview
Problem
Multi-beam writing in semiconductor devices faces challenges with positional deviations of beams, leading to inaccurate dose distribution and pattern quality, requiring a method to evaluate and control the controllability and resolution of gray beams effectively.
Innovation Solution
A multi-charged particle beam evaluation method involving writing evaluation patterns with varying line widths at a predetermined pitch, measuring line widths, and analyzing differences to extract variations, using Fast Fourier Transform to assess controllability and resolution of gray beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-beam writing is used to improve throughput, then productivity increases, but beam positional deviations cause dose distribution inaccuracies that worsen manufacturing precision
Solution Approach 1:
The patent implements feedback control by measuring actual beam positions, calculating deviation amounts from intended positions, and using these deviations to modulate doses of surrounding beams. This closed-loop approach compensates for positional errors while maintaining high-speed multi-beam writing capability.
Solution Approach 2:
The patent dynamically adjusts beam dose parameters based on measured positional deviations. By changing dose values according to deviation amounts and distributing these adjusted doses to surrounding beams, the system maintains pattern accuracy despite positional variations inherent in multi-beam writing.
2Manufacturing precision
If dose modulation processing is applied to compensate for beam deviations, then manufacturing precision is maintained, but the complexity of dose calculation and control increases
Solution Approach 1:
The patent segments the dose modulation process into distinct steps: measuring individual beam positions, calculating deviation amounts for each beam, determining dose adjustments based on deviations, and distributing modified doses to affected beams. This segmentation makes the complex control process more manageable and systematic.
Solution Approach 2:
The patent introduces an intermediary processing step that acts as a mediator between beam position measurement and final pattern formation. The dose modulation processing serves as an intermediary mechanism that translates positional deviations into compensatory dose adjustments, simplifying the overall control architecture.
3Adaptability or versatility
If gray beams with non-100% doses are used for pattern writing, then flexibility in dose distribution is improved, but dimensional accuracy and positional accuracy of written patterns deteriorate
Solution Approach 1:
The patent dynamically adjusts gray beam dose parameters based on measured positional deviations. By changing dose values according to specific deviation amounts and spatial relationships, the system maintains dimensional accuracy while preserving the flexibility benefits of gray beam writing for complex patterns.
Solution Approach 2:
The patent applies local quality control by individually adjusting doses of gray beams based on their specific positional deviations and local pattern requirements. Each beam's dose is customized according to its deviation characteristics, maintaining overall pattern accuracy while allowing local flexibility for complex geometries.
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 allows for quantitative and easy evaluation of beam controllability and resolution, ensuring precise pattern formation by adjusting doses and positions, thereby improving dimensional and positional accuracy.
Implementation Method 1
writing a plurality of evaluation patterns on a substrate by using multi charged particle beams
Data Source
AI summary
In one embodiment, a multi charged particle beam evaluation method includes writing a plurality of evaluation patterns on a substrate by using multi charged particle beams, with a design value of a line width changed by a predetermined change amount at a predetermined pitch, measuring the line widths of the plurality of evaluation patterns thus written, and extracting a variation in a specific period of a distribution of differences between results of a measurement value and the design value of each of the line widths of the plurality of evaluation patterns. The predetermined change amount is equal to or larger than data resolution and smaller than a size of each of pixels, each of which is a unit region to be irradiated with one of the multi charged particle beams.