FIB Scan Sequencing to Reduce Pixel Energy Overlap
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Solution Overview
Problem
The precision of focused ion beam (FIB) and charged particle lithography is limited by beam overlap due to energy deposition overlap between pixels, leading to reduced spatial resolution and increased beam damage during high-speed or high-precision imaging and cutting processes.
Innovation Solution
Implementing a beam control method that uses reduced or sub-sampled scanning patterns with maximized time and space differences between consecutive beam locations, such as random or structured variable distance/time scanning, to minimize beam overlap and deposition overlap between pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher beam energy or faster scanning is used to increase productivity, then imaging/cutting speed improves, but beam overlap between pixels increases reducing spatial resolution and increasing beam damage
Solution Approach 1:
The patent applies dynamics by making the beam scanning pattern adaptive and variable rather than fixed and regular. The scanning pattern dynamically adjusts the distance and time between consecutive beam locations based on real-time conditions, allowing the system to optimize between speed and precision for different regions and materials. This dynamic approach enables faster scanning while maintaining controlled beam overlap through intelligent pattern variation.
Solution Approach 2:
The patent implements preliminary action by pre-calculating and pre-planning the optimized scanning pattern before beam irradiation begins. The system determines the optimal sequence of pixel traversal and beam parameters in advance, accounting for material properties, desired resolution, and productivity requirements. This preliminary planning ensures that beam overlap is controlled from the outset, preventing excessive energy deposition while maintaining high scanning speeds.
2Manufacturing precision
If higher beam energy is deposited to improve cutting precision, then milling precision improves, but beam damage to surrounding areas increases
Solution Approach 1:
The patent applies local quality by tailoring the beam scanning parameters specifically to each pixel location and its relationship to neighboring pixels. The system adjusts beam energy, dwell time, and scanning sequence locally based on the specific material properties and desired outcome at each position. This localized control ensures that sufficient energy is deposited for precise milling at the target location while minimizing energy spread and damage to surrounding sensitive areas.
Solution Approach 2:
The patent converts the potentially harmful effect of beam scattering and energy spread into a benefit by strategically utilizing the scattered beam distribution. Instead of avoiding all scattering, the system controls and directs the scattered energy away from sensitive areas while concentrating the primary beam energy where precision milling is needed. The scanning pattern is designed so that scattered energy from one pixel does not adversely affect adjacent pixels, transforming the harmful scattering effect into a controlled process feature.
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 image resolution, decreases spatial extent of milling damage, and increases line precision by reducing beam overlap, thereby improving the precision of imaging and cutting processes in FIB, SEM, HIM, and charged particle lithography.
Implementation Method 1
the primary beam incident on the specimen leads to the creation of multiple scattering events and the expulsion of ions from a volume that is larger than the primary beam illumination area
Data Source
AI summary
A beam control method is provided that can be implemented with any hardware system for imaging and/or cutting such as SEM/FIB/HIM or charged particle lithography which alleviates the deposited energy overlap between pixels to increase resolution and precision while reducing damage. The method includes scanning a workpiece with e-beam lithography, proton lithography, ion beam lithography, optical lithography, ion beam imaging or FIB in a reduced or sub-sampled pattern, to reduce beam overlap, which can include the step of scanning the beam ensuring that there is the largest difference in time and space between consecutive beam locations.