Multibeam Electron Writing with Current Density Feedback Correction
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Solution Overview
Problem
The current density distribution of electron beams emitted from a thermionic-emission electron source changes as the cathode wears out, affecting pattern writing accuracy in multibeam writing apparatuses.
Innovation Solution
A multibeam writing method that includes measuring the current density distribution, performing beam adjustments to correct deviations, and restricting the use of beams with low current densities when corrections are insufficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple beams are used for writing, then productivity is significantly increased, but manufacturing precision deteriorates due to changes in current density distribution as the cathode wears out
Solution Approach 1:
The system measures the actual current density distribution of the multiple beams and feeds this information back to the control unit. Based on this feedback, the control unit calculates correction values and adjusts the beam current densities to compensate for deviations caused by cathode wear, thereby maintaining pattern writing accuracy while using multiple beams for high productivity
Solution Approach 2:
The system dynamically changes the current density parameters of individual beams by applying correction values to each beam's current density. This allows the system to compensate for cathode wear effects and maintain uniform beam quality across all multiple beams, preserving manufacturing precision while maintaining high productivity through multibeam operation
2Manufacturing precision
If beam adjustment is performed to correct current density distribution, then manufacturing precision is maintained, but device complexity increases due to additional measurement and control mechanisms
Solution Approach 1:
The system performs self-diagnosis and self-correction by automatically measuring its own beam current density distribution and adjusting the beams accordingly. The control unit calculates correction values based on measured data and autonomously adjusts the beam parameters, reducing the need for external intervention and complex manual calibration mechanisms
3Manufacturing precision
If beams with low current density are restricted, then manufacturing precision is maintained, but productivity decreases due to reduction in the number of usable beams
Solution Approach 1:
The system performs preliminary measurement of the current density distribution of all multiple beams before writing operations. By identifying beams with insufficient current density in advance, the system can restrict only those specific beams that would compromise manufacturing precision, while continuing to use all other beams at full capacity, thereby maintaining high productivity
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
The method maintains pattern writing accuracy by adjusting and restricting beams, thereby compensating for cathode wear and ensuring consistent beam quality.
Implementation Method 1
a thermionic-emission electron source with a cathode serving as a heater is used. In this electron source, electrons are emitted by heating the cathode
Data Source
AI summary
In one embodiment, a multibeam writing method includes acquiring a current density distribution of multiple beams formed using a charged particle beam emitted from a charged particle source, comparing the acquired current density distribution with a preset ideal shape of the current density distribution, and performing a beam adjustment on the multiple beams in a case where a difference at a predetermined position is greater than a threshold value.