Deflection Settling Time Determination for Charged Particle Beam Writing
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Solution Overview
Problem
Current methods for determining the optimal settling time for electron beam deflection in semiconductor device patterning are inefficient, requiring numerous evaluation patterns to exclude variations and resulting in high costs due to frequent recalculations, which impact writing accuracy and throughput.
Innovation Solution
A method involving writing evaluation patterns while changing the main deflection settling time, measuring position displacement, performing fitting on the amplifier output waveforms, and determining the settling time within a predetermined range, allowing for efficient identification of the optimal settling time without extensive pattern writing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple evaluation patterns are written while changing main deflection settling time to determine optimal settling time, then writing accuracy is improved, but writing time and measurement time increase tremendously
Solution Approach 1:
The patent extracts the essential characteristic needed for determining optimal settling time by measuring only the head tail distance of evaluation patterns rather than analyzing complete patterns. This extraction of key measurement elements dramatically reduces measurement time while maintaining accuracy in determining the optimal settling time
Solution Approach 2:
Instead of writing and measuring multiple complete evaluation patterns to exclude variations, the patent uses partial measurement (head tail distance only) with fewer patterns. This partial action approach achieves sufficient measurement accuracy without the tremendous time cost of complete pattern analysis
2Manufacturing precision
If evaluation patterns are written regularly to newly determine optimal main deflection settling time, then writing accuracy is maintained, but cost increases
Solution Approach 1:
The system performs self-diagnosis and self-adjustment by automatically determining the optimal settling time through the simplified measurement method. This self-service capability eliminates the need for expensive external evaluation and frequent recalibration, reducing operational costs while maintaining accuracy
Solution Approach 2:
The patent changes the measurement parameter from complete pattern analysis to head tail distance measurement. This parameter change enables faster, cheaper determination of optimal settling time while maintaining the ability to ensure writing accuracy
3Productivity
If main deflection settling time is set to short time, then throughput is improved, but writing accuracy may be reduced due to insufficient settling time
Solution Approach 1:
The patent performs preliminary determination of the optimal settling time characteristics specific to each apparatus through the simplified head tail distance measurement method. This preliminary action establishes the precise optimal settling time parameter that maximizes both throughput and accuracy for each specific system configuration
Solution Approach 2:
The patent establishes a dynamic optimization approach where the optimal settling time is determined based on specific apparatus characteristics rather than using fixed conservative values. This dynamic parameter adjustment allows each system to operate at its optimal point, achieving both high throughput and high accuracy
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
This approach reduces the time and cost associated with determining the optimal settling time, enabling precise and efficient electron beam deflection for semiconductor device patterning by distinguishing between settling errors and variations, thus improving writing accuracy and throughput.
Implementation Method 1
a charged particle beam is deflected by applying a voltage outputted from an amplifier to a main deflector
Data Source
AI summary
In one embodiment, a settling time determination method includes deflecting a charged particle beam by applying a voltage outputted from an amplifier to a first deflector while changing a deflection settling time, and writing an evaluation pattern, measuring a position of the evaluation pattern, and determining a position displacement amount of the measured position from a design position, performing fitting of the position displacement amount for the deflection settling time on a first output waveform of the amplifier, and determining a deflection settling time in which the position displacement amount is within a predetermined range.