Charged Particle Beam Writing Apparatus Tracking Calculation
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Solution Overview
Problem
The increasing miniaturization of semiconductor device patterns leads to a need for improved speed and precision in processing deflection data for electron beam writing, which is hindered by communication delays in transmitting deflection signals, resulting in throughput degradation due to delayed writing processing in charged particle beam writing apparatuses.
Innovation Solution
A charged particle beam writing apparatus and method that employs multiple tracking calculation units to calculate deflection amounts while allowing for a mutual overlapping time period, with a switching unit that inputs an end signal to switch between calculation units, enabling continuous deflection of the charged particle beam without delays, even during stage movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical transmission is used to transmit deflection signals, then communication reliability is improved, but communication delay increases causing throughput degradation
Solution Approach 1:
The patent applies preliminary action by having the second tracking calculation unit start calculating deflection amounts for the next subfield in advance before the current subfield writing is completed. This overlapping calculation approach ensures that deflection data is ready before it is needed, eliminating waiting time and preventing throughput degradation while maintaining reliable optical transmission.
2Measurement precision
If tracking calculation is performed sequentially for each subfield, then calculation precision is maintained, but processing speed decreases due to communication delay
Solution Approach 1:
The patent segments the tracking calculation function into multiple independent tracking calculation units. Each unit is responsible for calculating deflection amounts for specific subfields, allowing parallel processing of multiple subfields simultaneously. This segmentation maintains calculation precision through dedicated units while dramatically improving processing speed by eliminating sequential dependencies.
Solution Approach 2:
The patent implements continuity of useful action by having the second tracking calculation unit continuously calculate deflection amounts for upcoming subfields while the first unit processes current subfields. This overlapping calculation ensures that deflection data generation is continuous and never waits for optical transmission delays, maintaining both precision and speed.
3Reliability
If deflection data is transmitted via optical cable, then signal integrity is improved, but transmission time increases causing writing delay
Solution Approach 1:
The patent applies preliminary action by pre-calculating deflection amounts for multiple future subfields using the second tracking calculation unit before the optical transmission is needed. This advance calculation ensures that when data is transmitted via optical cable, it is already ready, eliminating the impact of transmission time on writing speed while maintaining signal integrity through reliable optical transmission.
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 inhibits throughput degradation caused by communication delays, allowing for efficient and precise pattern writing by ensuring continuous processing and reducing unnecessary standby times, thereby maintaining high processing speed and precision.
Implementation Method 1
a deflector configured, while the stage is moving, to deflect the charged particle beam to an n-th small region, based on a signal output from one of the plurality of tracking calculation units before switching the plurality of tracking calculation units, and to deflect the charged particle beam to an (n+1)th small region
Data Source
AI summary
A charged particle beam writing apparatus includes a plurality of tracking calculation units to calculate a deflection amount of the charged particle beam in regard to a movable substrate, a switching unit for each of a plurality of virtual small regions of the substrate, to input an end signal indicating completion of charged particle beam emission to a respective small region, and to switch from output of one of the tracking calculation units to output of another of the tracking calculation units, and a deflector, while a substrate is moving, to deflect the charged particle beam to an n-th small region, based on an output from one of the tracking calculation units before switching and to deflect the charged particle beam to an (n+1)th small region based on an output from another of tracking calculation units after switching the plurality of tracking calculation units.