Charged Particle Beam Deflection Settling Time Optimization
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Solution Overview
Problem
The increase in the number of sub-deflection regions in semiconductor devices due to smaller circuit pattern dimensions leads to longer main deflection settling times, reducing the throughput of electron beam writing apparatuses.
Innovation Solution
A method is developed to determine the main deflection settling time by writing patterns in sub-deflection regions using both short and long distance movements, measuring displacements, and adjusting the settling time to maintain displacement within specific ranges, optimizing the main deflection settling time for improved throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the main deflection settling time is increased to ensure accurate pattern writing, then the manufacturing precision is improved, but the productivity decreases
Solution Approach 1:
The patent applies dynamics by making the main deflection settling time variable rather than fixed. The control unit dynamically adjusts the settling time based on the writing position and deflection amount, using longer settling times for large deflection amounts and shorter settling times for small deflection amounts. This dynamic adjustment optimizes both pattern writing accuracy and throughput by matching the settling time to the actual deflection requirements at each writing position.
2Manufacturing precision
If the number of sub-deflection regions is increased to improve positional accuracy, then the manufacturing precision is improved, but the productivity decreases due to increased main deflection operations
Solution Approach 1:
The patent applies local quality by differentiating the main deflection settling time based on the specific writing position and deflection amount required for each sub-deflection region. Instead of using a uniform settling time for all regions, the control unit determines appropriate settling times locally for each writing position, allowing smaller settling times for regions requiring small deflections and larger settling times for regions requiring large deflections. This resolves the contradiction by optimizing the settling time for each local region's specific requirements.
Data Source
AI summary
An electron beam is moved a long distance along a straight line from a sub-deflection region 101a to a diagonally opposite sub-deflection region 123w by main deflection of the beam, and a pattern P is written in the sub-deflection region 123w. The former writing step is repeated a plurality of times each with a different main deflection settling time, thereby writing a plurality of patterns P. The amount of displacement of each pattern P from its designed position is then measured. Further, the latter writing step is also repeated a plurality of times each with a different main deflection settling time, thereby writing another plurality of patterns P. The amount of displacement of each pattern P from its designed position is then measured.