Electron Beam Lithography Pattern Ranking and Segmentation
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Solution Overview
Problem
Conventional electron beam lithography apparatuses face challenges in achieving high-speed and high-accuracy drawing due to the need for adjusting electron beam shape and deflection settlement wait time according to the degree of importance of device patterns, where increasing beam size for faster processing compromises accuracy and vice versa.
Innovation Solution
An electron beam lithography apparatus that includes a storage for pattern rank data, a divided drawing pattern data generation unit, and a settlement wait time determination unit to adjust the electron beam shape and deflection wait time based on the rank of the device pattern, allowing for prioritization of accuracy over speed for high-importance patterns and speed over accuracy for low-importance patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of the electron beam is increased to improve processing speed, then throughput is improved, but electron scattering increases and drawing accuracy deteriorates
Solution Approach 1:
The patent divides the drawing pattern into multiple subfields and processes different subfields with different beam sizes according to their importance rank. High-importance patterns use smaller beams for accuracy, while low-importance patterns use larger beams for speed, resolving the contradiction between processing speed and drawing accuracy through spatial segmentation.
Solution Approach 2:
The patent applies different beam qualities (sizes) to different regions of the drawing pattern based on their importance. High-importance device patterns receive high-quality small beams for precision, while low-importance patterns receive lower-quality large beams for throughput, making the beam quality local rather than uniform across the entire pattern.
2Productivity
If the settlement wait time is reduced to improve processing speed, then throughput is improved, but beam positioning accuracy deteriorates
Solution Approach 1:
The patent segments the drawing process by rank, applying different settlement wait times to different importance levels. High-importance patterns use longer wait times for accurate beam positioning, while low-importance patterns use shorter wait times for faster processing, resolving the contradiction through temporal segmentation based on pattern priority.
Solution Approach 2:
The patent dynamically adjusts the settlement wait time based on the importance rank of the current drawing pattern being processed. The system changes operational parameters (wait time) in real-time according to the specific requirements of each pattern, optimizing both speed and accuracy for different processing stages.
3Manufacturing precision
If all device patterns are drawn with high accuracy to ensure overall quality, then drawing accuracy is improved, but processing speed deteriorates
Solution Approach 1:
The patent ensures overall drawing accuracy by applying high-quality processing selectively to high-importance patterns while using lower-quality faster processing for low-importance patterns. This local differentiation maintains the required accuracy level for critical device features while improving overall throughput through optimized processing of non-critical features.
Solution Approach 2:
The patent changes processing parameters (beam size, settlement wait time) based on the importance rank of device patterns. By adjusting these parameters dynamically, the system achieves high accuracy for important patterns at acceptable processing speeds, while faster processing for less important patterns improves overall throughput without compromising critical quality requirements.
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 enables high-speed and high-accuracy drawing by optimizing the electron beam shape and deflection wait time according to the pattern rank, improving overall processing efficiency while ensuring required accuracy levels.
Implementation Method 1
the deflection position of an electron beam is changed by a deflector
Implementation Method 2
the beam which has passed through the mask is deflected and bent back by a downstream deflector
Implementation Method 3
shaping a beam cross section into the shape of a stencil pattern
Implementation Method 4
the scattering of electrons in the beam increases due to Coulomb effects
Data Source
AI summary
An electron beam lithography apparatus includes a storage for storing data on a drawing pattern assigned a rank based on an accuracy required for a device pattern, a drawing pattern adjustment unit to generate data on divided drawing patterns based on the rank, a settlement wait time adjustment unit to determine a settlement wait time based on the rank, and a controller to draw the device pattern while irradiating an electron beam based on the data on the divided drawing patterns and the settlement wait time. The drawing pattern adjustment unit determines upper limits on the long-side length of a divided drawing pattern or on the area of the divided drawing pattern based on the rank, and divides the drawing pattern based on the upper limits.