Multi-Beamlet Charged Particle Device for High-Speed Wafer Inspection

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Solution Overview

Problem

Charged particle beam devices, such as scanning electron microscopes, face challenges in achieving high throughput and resolution due to limited probe current and electron-electron interactions, making it difficult to inspect specimens quickly and accurately at the nanoscale.

Innovation Solution

A charged particle beam device configured with a beam source, an aperture device creating multiple beamlets, and an electrostatic multipole device to individually influence and scan these beamlets over a specimen along evenly spaced lines, increasing data collection rate and inspection efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple beamlets are used to increase throughput, then inspection speed improves, but controlling and scanning individual beamlets becomes increasingly challenging

Engineering Contradiction:

Improveinspection throughputVSAvoidbeam control complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent divides a single electron beam into multiple independent beamlets using an aperture device with multiple apertures arranged in a specific pattern. Each beamlet can be independently controlled and scanned, allowing parallel inspection of multiple areas on the specimen simultaneously. This segmentation enables high throughput while maintaining individual beam control through dedicated deflection and focusing mechanisms for each beamlet.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent arranges the multiple apertures in a two-dimensional array pattern rather than a simple linear sequence. This spatial arrangement in another dimension allows for more efficient packing of beamlets and enables independent control of each beamlet's position and focus. The 2D aperture configuration facilitates parallel scanning across multiple scan lines, significantly increasing inspection throughput while maintaining manageable control complexity through systematic addressing of each beamlet.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If the number of apertures is increased to create more beamlets, then data collection rate improves, but maintaining good field qualities becomes difficult

Engineering Contradiction:

Improvedata collection rateVSAvoidfield quality uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements individual focusing and aberration correction mechanisms for each beamlet generated by the multiple apertures. Each beamlet can have its focus and field quality independently optimized, allowing the system to maintain high uniformity across all beamlets even when a large number of apertures are used. This local quality control ensures that each beamlet delivers consistent performance across the entire field of view.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs adjustable electrostatic or magnetic fields for each beamlet to dynamically control focus, deflection, and aberration correction parameters. By independently tuning these parameters for each beamlet, the system maintains uniform field qualities across all beamlets regardless of the total number of apertures. This parameter control allows real-time optimization of each beamlet's performance to ensure consistent data collection quality.

Inventive Principle:

Principle #35Parameter changes

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 solution enhances throughput and inspection accuracy by allowing simultaneous inspection of multiple spots with independently controlled beamlets, reducing idle times and improving aberration correction, thereby facilitating high-speed wafer inspection.

Implementation Method 1

a beam source configured to generate a charged particle beam propagating along an optical axis

Methodology Applied

Scientific EffectElectron beam generation: Electron Beam

Implementation Method 2

an aperture device with a first number of apertures configured to create a first number of beamlets from the charged particle beam

Methodology Applied

Scientific EffectPhysical aperture filtering: Filter (physical)

Implementation Method 3

an electrostatic multipole device configured to individually influence the beamlets

Methodology Applied

Scientific EffectElectrostatic field interaction: Electric Field

Data Source

PatentUS10249472B2Charged particle beam device, charged particle beam influencing device, and method of operating a charged particle beam device

Publication Date: 2019.04.02 ICT INTEGRATED CIRCUIT TESTING GESELLSCHAFT FUER HALBLEITERPRUEFTECHNIK GMBH

AI summary

A charged particle beam device is described, which includes: a beam source configured to generate a charged particle beam propagating along an optical axis (A); an aperture device with a first number of apertures configured to create a first number of beamlets from the charged particle beam, wherein the first number is five or more, wherein the apertures are arranged on a ring line around the optical axis (A) such that perpendiculars of the apertures onto a tangent of the ring line are evenly spaced. The charged particle beam device further includes an electrostatic multipole device configured to individually influence the beamlets. Further, a charged particle beam influencing device and a method of operating a charged particle beam device are described.