Multi-Beam Writing Correction for Circuit-Induced Beam Shift

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Solution Overview

Problem

Multi-beam writing techniques face challenges in maintaining writing accuracy due to Coulomb effects, electric field influences from control circuit capacitances, and magnetic field impacts, which are difficult to correct using conventional methods, especially when increasing the number of conditions for correction increases the complexity of creating correction tables.

Innovation Solution

The method involves dividing the data path into blocks based on input/output circuits and wiring groups to calculate shift amounts for each block, accounting for electric and magnetic field influences, and adjusting beam irradiation positions and doses accordingly to correct for beam position displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the number of blocks or correction conditions is increased to improve writing accuracy, then the precision of beam position correction is improved, but the complexity of creating correction tables and acquiring parameters increases

Engineering Contradiction:
Improvebeam position correction precisionVSAvoidcorrection table complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the conventional method of creating complex correction tables through manual measurement and data processing with a neural network-based automated system. The neural network learns the relationship between beam positions and correction amounts from training data, automatically generating correction values without requiring complex manual table creation. This substitutes the mechanical/data-processing system with an intelligent system that simplifies the workflow while maintaining or improving correction precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a virtual model of the beam writing system through the neural network, which copies and learns from training data representing the complex interactions between multiple beams and the writing medium. This virtual model then generates correction values that replicate the effects of complex physical measurements without requiring actual physical measurements for every correction scenario.

Inventive Principle:
Principle #26Copying

2Productivity

If multiple beams are used to increase writing throughput, then productivity is improved, but beam position displacement due to Coulomb effects increases

Engineering Contradiction:
Improvewriting throughputVSAvoidbeam position accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent performs preliminary correction by calculating beam position displacements caused by Coulomb effects before the actual writing process. The system computes correction values based on the planned beam irradiation pattern and applies these corrections in advance, ensuring that beams are positioned accurately despite the repulsive forces that will occur during multi-beam writing. This preliminary correction prevents position errors rather than correcting them after they occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies preliminary anti-action by calculating and applying correction values that counteract the expected Coulomb repulsion effects before they occur. The system predicts the beam position displacement caused by inter-beam repulsion and applies equal and opposite corrections to the beam positions, effectively neutralizing the harmful effect before it can degrade writing accuracy.

Inventive Principle:
Principle #9Preliminary anti-action

3Manufacturing precision

If electric field and magnetic field influences are corrected using conventional techniques, then beam position accuracy is improved, but the ability to correct for circuit-specific variations is insufficient

Engineering Contradiction:
Improvebeam position accuracyVSAvoidcorrection method adaptability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the approach from using fixed correction parameters to using a neural network that can adapt its parameters based on input conditions. The system takes into account various parameters including beam positions, irradiation patterns, and circuit characteristics, and dynamically generates appropriate correction values. This allows the same system to adapt to different circuit layouts and writing conditions without requiring manual reconfiguration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements self-service by enabling the system to automatically correct for its own circuit-specific variations and field effects. The neural network learns from training data that includes the specific characteristics of the control circuits and blanking aperture array substrate, allowing the system to self-correct for variations in electric and magnetic fields generated by its own components without requiring external calibration or adjustment.

Inventive Principle:
Principle #25Self-service

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 improves writing accuracy by mitigating the effects of electric and magnetic fields, reducing beam position displacement, and simplifying the process of acquiring correction parameters, thereby enhancing the precision of multi-beam writing.

Implementation Method 1

Each electrode of the electrode pair (blanker) is controlled to have either the same potential or a different potential to thereby provide blanking deflection to the passing electron beam

Methodology Applied
Scientific EffectElectrostatic deflection: Electrostatics

Implementation Method 2

The blanking aperture array substrate includes an electrode pair for individually deflecting a beam, with a beam passage aperture provided between the electrode pair

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 3

the influence of a magnetic field due to the drive current for the control circuit

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 4

inter-electron repulsion can lead to beam position displacement or de-focusing on a sample surface

Methodology Applied
Scientific EffectCoulomb repulsion: Coulomb's Law

Data Source

PatentUS12046447B2Multi-charged-particle-beam writing method, multi-charged-particle-beam writing apparatus, and computer-readable recording medium
Publication Date: 2024.07.23 NUFLARE TECH INC
  • US12046447B2 patent drawing
  • US12046447B2 patent drawing
  • US12046447B2 patent drawing

AI summary

In one embodiment, a multi-charged-particle-beam writing method includes dividing a data path into a plurality of first blocks based on at least either one of each of a plurality of input/output circuits and a plurality of wiring groups, and calculating a first shift amount for multiple beams for each of the plurality of first blocks. The data path is for inputting control data to a cell array on a blanking aperture array substrate. The control data is for controlling ON/OFF of each beam of the multiple beams. Each of the plurality of wiring groups includes a plurality of pieces of wiring connected to the plurality of input/output circuits and grouped together based on inter-wiring distance. The first shift amount is due to at least one of an electric field and a magnetic field for each of the plurality of first blocks. An irradiation position or a dose of the multiple beams is corrected based on the first shift amount, and irradiation is performed.