Charged Particle Beam Deflection Correction for Semiconductor Writing
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Solution Overview
Problem
In electron beam writing for semiconductor devices, the increasing number of shots in the deflection region affects the shape of the deflection region, making it difficult to evaluate and correct, which impacts the accuracy of circuit patterns due to limitations in measurable beam size and evaluation pattern size.
Innovation Solution
A charged particle beam writing apparatus and method that includes a number of shots calculation circuit, deflection position correcting circuit, and a deflector to adjust the number of shots and correct the deflection position based on the calculated number, ensuring accurate pattern writing by dividing the writing region into multiple processing regions and adjusting the dose amount to account for changes in the irradiation region shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of shots in the deflection region is increased to improve writing efficiency, then productivity increases, but the shape of the deflection region changes due to voltage application effects, causing deflection position deviation and reducing manufacturing precision
Solution Approach 1:
The patent applies preliminary action by calculating the cumulative number of shots in advance for each deflection region and pre-determining the corresponding deflection position deviations based on predetermined values. This allows the writing apparatus to compensate for deflection position deviations before they occur during the writing process, thereby maintaining manufacturing precision while enabling increased writing efficiency through higher shot counts.
2Manufacturing precision
If the beam size is reduced to improve resolution for high integration LSI, then manufacturing precision improves, but the measurable size by measuring instruments becomes limited, making it difficult to evaluate and correct deflection region shape changes
Solution Approach 1:
The patent introduces an intermediary approach by using predetermined deflection position deviation values that are calculated based on the cumulative number of shots, rather than relying solely on direct measurement of the actual deflection region shape. This intermediary calculation method enables accurate correction even when direct measurement becomes difficult due to reduced beam size, thus maintaining both manufacturing precision and evaluation capability.
3Measurement precision
If the evaluation pattern size is increased to improve measurement accuracy of deflection region shape, then measurement precision improves, but the number of shots that can be performed in the deflection region is limited, preventing accurate evaluation of shot-dependent effects
Solution Approach 1:
The patent applies preliminary action by pre-calculating the cumulative number of shots for each deflection region and determining the corresponding deflection position deviations in advance. This eliminates the need to perform a large number of shots during evaluation, as the correction values are predetermined based on shot count, thereby enabling accurate evaluation with fewer shots while maintaining measurement precision.
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
Enables precise writing by accurately calculating and correcting the number of shots and dose amount, improving the accuracy of circuit patterns and overcoming limitations in measurable beam size, thus enhancing the precision of the writing process.
Implementation Method 1
a deflector configured to deflect the charged particle beam to a corrected deflected position on a surface of a target object
Data Source
AI summary
A charged particle beam writing apparatus includes a number of shots calculation circuit to calculate the number of shots in the case where a deflection region is irradiated with a shot of a charged particle beam, a deflection position correcting circuit to correct a deflection position of the charged particle beam to be shot in the deflection region, depending on the number of shots to be shot in the deflection region, and a deflector to deflect the charged particle beam to a corrected deflected position on the target object.