Charged Particle Beam Writing Drift Correction
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Solution Overview
Problem
The existing charged particle beam writing methods face challenges in maintaining writing accuracy and throughput due to deflection distortion and time-dependent random deviations, particularly in the FWD-BWD mode where the stage moving time is long and writing accuracy is compromised.
Innovation Solution
A charged particle beam writing method that performs multiple strokes with alternating forward and backward writing directions, shifting the substrate's reference point by preset amounts in the width direction, and adjusting the moving direction for each stripe, allowing for improved connection accuracy and reduced influence of random deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple writing is performed in a plurality of strokes to reduce the influence of random deviations, then writing accuracy is improved, but stage moving time increases and throughput decreases
Solution Approach 1:
The patent performs drift correction before each stroke of writing, proactively compensating for random deviations before they affect writing accuracy. This preliminary action allows the system to maintain high precision without requiring excessive stage moving time for corrective maneuvers during writing.
Solution Approach 2:
The writing process is divided into multiple strokes, with drift correction performed between strokes. This segmentation allows the system to address random deviations at specific intervals rather than requiring continuous correction, optimizing the balance between writing accuracy and throughput.
2Productivity
If FWD-BWD mode is used to reduce stage moving time, then throughput is improved, but writing accuracy deteriorates due to deflection distortion
Solution Approach 1:
The patent dynamically changes the moving direction parameter for each stripe based on the current stroke number and stripe position. By alternating between forward and backward directions in a controlled manner, the system maintains the speed benefits of FWD-BWD mode while compensating for deflection distortion through directional variation.
Solution Approach 2:
The writing direction is periodically alternated between forward and backward modes for different stripes within each stroke. This periodic action helps distribute and average out deflection distortion effects while maintaining efficient stage movement, thus preserving both throughput and writing accuracy.
3Speed
If the number of forward and backward writing operations is unequal, then writing speed varies, but connection accuracy at stripe boundaries deteriorates
Solution Approach 1:
The patent implements a control mechanism that tracks the number of forward and backward writing operations and adjusts the moving direction for subsequent stripes to equalize the counts. This feedback-based control ensures that connection accuracy at stripe boundaries is maintained while allowing writing speed to vary optimally across different regions.
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 enhances writing accuracy and throughput by reducing stage moving time and equalizing the number of forward and backward writing operations, thereby minimizing the impact of random deviations and maintaining high precision.
Implementation Method 1
a beam position is adjusted by performing drift correction periodically... by irradiating a charged particle beam onto the substrate
Data Source
AI summary
In one embodiment, a charged particle beam writing method is for writing a pattern in a writing area on a substrate by irradiating a charged particle beam onto the substrate while moving the substrate to write stripes sequentially, each of the stripes having a width W and shapes obtained by dividing the writing area by the width W. The method includes performing S times (S is an integer greater than or equal to two) strokes, each of the strokes which is a process writing the stripes in a multiplicity of 2n (n is an integer greater than or equal to one) while shifting a reference point of each of the stripes in the width direction by a preset stripe shift amount and changing a moving direction of the substrate for each of the stripes, and writing while the reference point of the stripes in the each of the strokes in the width direction of the stripes is shifted by a preset stroke shift amount in each of the strokes.