Charged Particle Beam Drift Correction via Shot Data Merging
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Solution Overview
Problem
Current charged particle beam writing apparatuses face challenges in performing drift correction with high accuracy due to increased calculation complexity, making real-time correction impractical, especially as the number of shots increases, and struggle to maintain accuracy with varying shot intervals.
Innovation Solution
A charged particle beam writing apparatus and method that generate shot data including shot size, position, and beam ON/OFF time, calculate drift amounts based on this data for every predetermined area or number of shots, and use correction information to adjust the deflection amount, reducing calculation complexity while maintaining high accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If drift correction is calculated for each shot to maintain high accuracy, then correction accuracy is improved, but calculation time becomes excessively long and real-time correction becomes impractical
Solution Approach 1:
The patent combines multiple shot data calculations into a single cumulative calculation process. Instead of calculating drift correction for each individual shot, the system accumulates shot data (beam current, irradiation position, ON/OFF time) and performs a single drift correction calculation based on the cumulative total, thereby maintaining accuracy while reducing total calculation time.
Solution Approach 2:
The patent performs preliminary accumulation of shot data before performing the drift correction calculation. By pre-cumulating the beam current, irradiation position, and timing information for multiple shots, the system prepares the necessary data in advance, enabling faster real-time correction without sacrificing accuracy.
2Measurement precision
If the interval of calculation of accumulated beam irradiation amount is decreased to increase correction accuracy, then correction accuracy is improved, but calculation amount increases
Solution Approach 1:
The patent merges multiple small-interval calculations into a single cumulative calculation by accumulating beam irradiation data over extended periods. This approach maintains correction accuracy by considering the total accumulated effect while reducing the overall calculation burden by performing fewer, more comprehensive calculations.
3Device complexity
If the interval of calculation is increased to reduce calculation amount, then calculation amount is decreased, but correction accuracy is reduced
Solution Approach 1:
The system performs preliminary data accumulation at extended intervals while maintaining the capability for accurate drift correction. By pre-cumulating shot data over longer periods and performing correction calculations based on these accumulated totals, the system reduces calculation frequency and complexity while preserving correction accuracy through the cumulative approach.
4Ease of operation
If constant calculation interval is used to simplify processing, then processing simplicity is improved, but ability to cope with varying shot patterns is reduced
Solution Approach 1:
The patent implements a dynamic calculation approach where the system accumulates shot data flexibly based on varying shot patterns rather than using fixed constant intervals. The accumulation process adapts to different writing conditions and shot densities, allowing the system to maintain processing simplicity while being highly adaptable to varying shot patterns through the cumulative data gathering mechanism.
Data Source
AI summary
Drift correction is performed with high accuracy while reducing the calculation amount. According to one aspect of the present invention, a charged particle beam writing apparatus includes an emitter emitting a charged particle beam, a deflector adjusting an irradiation position of the charged particle beam with respect to a substrate placed on a stage, a shot data generator generating shot data from writing data, the shot data including a shot size, a shot position, and a beam ON⋅OFF time per shot, a drift corrector referring to a plurality of pieces of the shot data for every predetermined area irradiated with the charged particle beam, or for every predetermined number of shots of the charged particle beam irradiated, calculating a drift amount of the irradiation position of the charged particle beam with which the substrate is irradiated, based on the shot size, the shot position and the beam ON⋅OFF time, and generating correction information for correcting an irradiation position displacement based on the drift amount, and a deflection controller controlling a deflection amount achieved by the deflector based on the shot data and the correction information.