Charged Particle Beam Writing Stripe Region Division
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In charged particle beam writing methods, especially in electron beam lithography for semiconductor manufacturing, the accuracy of pattern positioning is compromised by varying pattern densities due to beam drift and charging issues, leading to reduced throughput and inability to maintain high precision.
Innovation Solution
The method involves virtually dividing the writing region into strip-shaped stripe regions, calculating the total area and number of shots for each stripe, and adjusting the writing order and settling time to minimize differences between adjacent regions, thereby reducing position deviations and maintaining high accuracy while preventing throughput reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the stripe width is set to be narrow to lessen the writing area per stripe, then the position accuracy is improved, but the throughput is reduced because the number of stripes is greatly increased
Solution Approach 1:
The writing region is divided into multiple stripe regions, and each stripe region is further divided into sub-stripe regions. This multi-level segmentation allows the system to maintain fine-grained control for position accuracy while managing the overall number of divisions to preserve throughput.
Solution Approach 2:
The patent applies different stripe width strategies to different regions based on local pattern density characteristics. Regions with sharp pattern density changes use narrower effective stripe widths for accuracy, while other regions use wider stripe widths to maintain throughput, thus applying local quality optimization.
2Manufacturing precision
If the time interval to measure beam drift amount is set to be very short to deal with sharp variation of pattern density, then the position accuracy is improved, but the throughput is reduced because the writing operation needs to be stopped
Solution Approach 1:
The patent performs preliminary calculation of pattern areas and number of shots for each stripe region before writing. Based on these pre-calculated values, the system determines optimal stripe boundaries that anticipate and prevent sharp pattern density changes, eliminating the need for frequent mid-writing measurements and stops.
Solution Approach 2:
The system uses pre-calculated pattern area and shot count information as feedback to optimize stripe region division. This feedback mechanism allows the system to adjust stripe boundaries to maintain position accuracy without requiring real-time measurements during writing that would interrupt throughput.
3Productivity
If conventional stripe division is used without considering pattern density variation, then the throughput is maintained, but the position accuracy is degraded at places with varying pattern density
Solution Approach 1:
The patent changes the parameter used for stripe division from fixed geometric intervals to variable intervals based on pattern area and number of shots calculations. This parameter change ensures that stripe boundaries are positioned to avoid sharp pattern density transitions, maintaining both throughput and position accuracy.
Data Source
AI summary
A charged particle beam writing method includes determining whether a difference between one of the total area of a pattern and the number of shots in a stripe region with respect to one of adjacent stripe regions of the stripe regions and one of the total area and the number of shots with respect to the other of the adjacent stripe regions exceeds a threshold value, re-dividing, when the difference exceeds the threshold value, a stripe region where the total area or the number of shots is larger than that of the other stripe region in the adjacent stripe regions so that the difference of the total area or the number of shots becomes lower than or equal to the threshold value, and writing a pattern in the stripe regions including a re-divided stripe region, in the writing order of arrangement of the stripe regions.