Multi-Charged Particle Beam Writing Apparatus Position Measurement

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Solution Overview

Problem

In multi-charged particle beam writing apparatuses, accurately measuring the positions of multiple beams is challenging due to beam deflection and distortion, especially with large numbers of beams, which affects the accuracy of beam position measurement and is difficult to fabricate defect-free aperture members.

Innovation Solution

A multi-charged particle beam writing apparatus with an inspection aperture member and current detector that allows for precise beam position measurement by scanning beams over an inspection aperture plate, dividing the blanking aperture array into measurement regions to minimize deflection and detect beam positions accurately, and using a control computer to generate a beam image and calculate positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple beams are used to increase writing throughput, then productivity is improved, but measurement precision deteriorates due to beam deflection and distortion

Engineering Contradiction:

Improvewriting throughputVSAvoidbeam position measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent divides the blanking aperture array into multiple measurement regions and measures beam positions in each region separately. This segmentation allows accurate measurement of beam positions without requiring large beam deflection, thus maintaining measurement precision while using multiple beams for high productivity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary measurement of beam positions before actual writing. By measuring beam positions in advance using the divided measurement regions, the system can compensate for beam shape distortion and establish accurate beam position data without affecting the high-speed writing process

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the number of beams is increased to improve throughput, then productivity is improved, but manufacturing precision deteriorates due to defects in aperture members

Engineering Contradiction:

Improvewriting throughputVSAvoidbeam position accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent uses measured beam position data to create a beam image and calculate actual beam positions, providing feedback on the true beam locations. This feedback mechanism allows the system to compensate for defects in aperture members and maintain accurate beam positioning even when using a large number of beams

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces reliance on perfect mechanical fabrication of aperture members with an optical/electronic measurement and calculation system. By using beam scanning and position calculation algorithms, the system compensates for manufacturing defects in the aperture members, maintaining precision without limiting the number of beams

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Difficulty of detecting and measuring

If beam scanning is performed over reflection marks to measure beam positions, then measurement capability is improved, but beam shape distortion increases due to large deflection

Engineering Contradiction:

Improvebeam position detection capabilityVSAvoidbeam shape accuracy

Core Design Contradiction:

Difficulty of detecting and measuringVSManufacturing precision

Solution Approach 1:

The patent segments the measurement process into multiple small-region measurements rather than one large scanning motion. By measuring beam positions in divided regions with minimal deflection, the system maintains beam shape accuracy while still achieving comprehensive beam position detection capability

Inventive Principle:

Principle #1Segmentation

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 enables accurate detection of beam positions and compensation for beam shape distortion, improving the accuracy of beam position measurement and reducing the impact of defects in aperture members, thus enhancing the precision of beam writing.

Implementation Method 1

a deflector deflects the multiple beams

Methodology Applied

Scientific EffectBeam deflection: Lorentz Force

Implementation Method 2

a current detector detecting a beam current of each of the multiple beams scanned over the inspection aperture plate

Methodology Applied

Scientific EffectBeam current detection: Electron Beam

Data Source

PatentUS10483088B2Multi charged particle beam writing apparatus and multi charged particle beam writing method

Publication Date: 2019.11.19 NUFLARE TECH INC

AI summary

In one embodiment, a multi charged particle beam writing apparatus includes an aperture plate forming multiple beams, a stage on which a writing target substrate is placed, a stage position detector detecting the position of the stage, an inspection aperture plate provided in the stage, the inspection aperture plate permitting one of the multiple beams to pass through the inspection aperture plate, a deflector deflecting the multiple beams, a current detector detecting a beam current of each of the multiple beams scanned over the inspection aperture plate in X and Y directions and passed through the inspection aperture plate, and a control computer generating a beam image based on the detected beam currents and calculating positions of the beams based on the beam image and the position of the stage.