Multibeamlet Charged Particle Device with Reconfigurable Blanking Circuit
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Solution Overview
Problem
Charged particle devices face challenges in maintaining adequate current density and consistent dosage when using multiple beamlets for lithography, as high current can cause sample heating and undesirable cross-talk between beamlets, while low current density reduces throughput.
Innovation Solution
A multibeamlet charged particle device with a reconfigurable blanking circuit and controller that selects and initializes beamlets, allowing continuous translation of the target and scanning of beamlets in the same direction to ensure even irradiation of regions on the target, maintaining constant velocity and focal spots stationary relative to the target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple beamlets are used to increase throughput, then productivity is improved, but current density decreases
Solution Approach 1:
The patent divides a single charged particle beam into multiple beamlets using a beam-splitting optical system. Each beamlet can be independently controlled and directed to different regions of the target, enabling parallel processing while maintaining adequate current density in each beamlet through independent optimization.
Solution Approach 2:
The patent introduces temporal dimension by sequentially activating different beamlets in a time-multiplexed manner. The blanking circuit enables each beamlet to be turned on and off independently, allowing the system to maintain high current density in active beamlets while achieving high overall throughput through parallel activation of multiple beamlets over time.
2Manufacturing precision
If high current is used to maintain adequate dosage, then manufacturing precision is improved, but temperature increases
Solution Approach 1:
The total charged particle dosage requirement is divided among multiple beamlets. Each beamlet delivers a portion of the required dosage, reducing the current density and heating effect in each individual beamlet while maintaining the total dosage through cumulative exposure from multiple beamlets.
Solution Approach 2:
The patent employs periodic activation of beamlets through the blanking circuit, which selectively enables and disables individual beamlets in a time-multiplexed sequence. This periodic action allows each beamlet to deliver its portion of dosage with reduced duty cycle, thereby minimizing thermal accumulation and sample heating while maintaining adequate total dosage.
3Device complexity
If beamlets share optical elements, then device complexity is reduced, but reliability deteriorates
Solution Approach 1:
The patent introduces dynamic control through the blanking circuit, which can selectively enable or disable individual beamlets in real-time. This dynamic switching capability allows the system to isolate beamlets and prevent cross-talk when needed, while still sharing optical elements to maintain reasonable device complexity. The blanking circuit acts as a dynamic gate that resolves the reliability issue without requiring complete optical element isolation.
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 method enhances throughput and reduces errors by ensuring consistent and reproducible charged particle dosage across the target, balancing current density and minimizing sample heating, while maintaining high resolution capabilities.
Implementation Method 1
forming a plurality of beamlets of charged particles
Implementation Method 2
a projection lens configured to project the plurality of selected beamlets onto the target
Data Source
AI summary
A method of method of operating a multibeamlet charged particle device is disclosed. In the method, a target attached to a stage is translated, and each step of selecting beamlets, initializing beamlets, and exposing the target is repeated. The step of selecting beamlets includes passing a reconfigurable plurality of selected beamlets through the blanking circuit. The step of initializing beamlets includes pointing each of the selected beamlets in an initial direction. The step of exposing the target includes scanning each of the selected beamlets from the initial direction to a final direction, and irradiating a plurality of regions of the target on the stage with the selected beamlets.