Multi-Charged Particle Beam Rotation Angle Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for measuring and adjusting the rotation angle of multi-beam images in multi-beam pattern writing are inefficient due to small current per beam, leading to increased measurement errors and long adjustment times, which affect positional and dimensional precision in semiconductor manufacturing.
Innovation Solution
A method involving two-dimensional scanning of a mark using representative beams to create a two-dimensional image, allowing for the acquisition and adjustment of the rotation angle of multi-charged particle beam images by rotating the shaping aperture array member or the beam image, thereby correcting the measured rotation angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple beams are used for measurement, then measurement coverage is improved, but measurement time increases significantly
Solution Approach 1:
The patent divides the multi-beam system into two groups: representative beams used for measurement and other beams not used for measurement. By selecting only a subset of beams (representative beams) to perform the rotation angle measurement, the measurement process becomes much faster while still providing accurate rotation angle data for the entire multi-beam image. This segmentation resolves the contradiction by making measurement time acceptable without sacrificing measurement coverage.
2Speed
If current per beam is increased, then measurement speed is improved, but beam current distribution becomes less uniform
Solution Approach 1:
The patent introduces a mark as an intermediary object that reflects the multi-beam image. By detecting the position of the mark rather than directly measuring each beam's position, the system can use higher beam currents for faster measurement without compromising positional precision. The mark acts as a mediator that converts beam position information into a detectable signal, allowing faster measurement while maintaining accuracy.
3Measurement precision
If all beams are used for measurement, then measurement completeness is improved, but measurement error increases due to small current per beam
Solution Approach 1:
The patent applies partial action by using only a subset of representative beams for measurement instead of all beams. This partial measurement approach actually reduces measurement error because each representative beam carries sufficient current for reliable detection, whereas using all beams with very small current per beam would increase error. The representative beams provide enough information to accurately determine rotation angle without the noise introduced by low-current beams.
Data Source
AI summary
According to one aspect of the present invention, a rotation angle measuring method of a multi-charged particle beam image includes two-dimensionally scanning a mark arranged on a stage in a multi-charged particle beam writing apparatus using, among multi-charged particle beams that can be used for exposure, a plurality of representative beams of which number is smaller than the number of beams constituting the multi-charged particle beams, creating a two-dimensional image of the plurality of representative beams based on signals obtained by two-dimensional scanning, and acquiring a rotation angle of the multi-charged particle beam image using the two-dimensional image.