Multi Beam Blanking Control via Time Segmentation
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Solution Overview
Problem
In multi-charged particle beam writing methods, high-speed and high-precision blanking control is challenging due to space and current restrictions on the blanking plate, leading to increased crosstalk and reduced throughput, especially when trying to maintain precise dose control and narrow beam pitches.
Innovation Solution
The method involves converting irradiation time into binary numbers, dividing it into multiple irradiation steps, and grouping these steps to reduce latency and improve data transmission efficiency, allowing for more precise control while maintaining circuit installation space constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blanking control circuit for each beam is placed on a blanking plate, then beam blanking control can be performed, but the circuit space is insufficient and crosstalk increases
Solution Approach 1:
The patent segments the blanking control into two parts: a common blanking control circuit placed outside the blanking plate that generates control signals, and individual blanking electrodes on the blanking plate that execute the control. This segmentation allows the complex control logic to be separated from the space-constrained blanking plate, reducing crosstalk while maintaining control precision.
Solution Approach 2:
The patent introduces a common blanking control circuit as an intermediary component that generates control signals for all beams. This intermediary circuit, placed outside the blanking plate, mediates between the control system and the individual blanking electrodes, enabling precise control without requiring complex circuits on the blanking plate itself.
2Productivity
If the beam pitch is narrowed to increase throughput, then more beams can be emitted simultaneously, but crosstalk between adjacent beams increases
Solution Approach 1:
The patent extracts the complex blanking control circuit from the blanking plate and places it outside. This extraction reduces the circuit complexity on the blanking plate, thereby reducing crosstalk between adjacent beams while allowing narrower beam pitch for increased throughput.
3Measurement precision
If a 10-bit control signal is used for precise dose control, then irradiation time can be accurately controlled, but the circuit becomes too complex for the available space
Solution Approach 1:
The patent segments the control signal processing: the 10-bit control signal is generated by the common blanking control circuit outside the blanking plate, then converted and distributed to individual blanking electrodes. This segmentation allows precise dose control through 10-bit signals without requiring complex circuits on the blanking plate itself.
Data Source
AI summary
A multi charged particle beam writing method includes dividing a maximum irradiation time per a shot into a digit number of first irradiation time periods, each of which is calculated by multiplying a corresponding second gray scale value by the quantization unit, where second gray scale values are gray scale values defined in decimal numbers converted from each digit value of data of binary numbers; dividing second irradiation time periods, which are a part of the first irradiation time periods into third irradiation time periods; dividing irradiation of each beam into the first irradiation steps of the third irradiation time periods and second irradiation steps of the remaining undivided first irradiation time periods; and irradiating a target object, in order, with the multi beams such that the groups are respectively composed of combination of at least two irradiation steps of first irradiation steps and second irradiation steps and the groups continue in order.