Segmented BSE Detector for Energy-Selective SEM Imaging

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Solution Overview

Problem

High landing energy electron beams in SEM systems cause increased interaction volume, leading to degraded imaging quality and challenges in efficiently collecting and discriminating backscattered electrons (BSEs) for accurate defect detection and metrology in semiconductor manufacturing.

Innovation Solution

A segmented charged-particle detector with concentric segments of sensitive material is used to discriminate BSEs by energy levels, allowing simultaneous collection and discrimination of BSE signals for improved imaging and metrology.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high landing energy electron beams are used to increase penetration capability, then the ability to detect deep structures and buried defects is improved, but the interaction volume increases causing degraded imaging quality

Engineering Contradiction:

Improvedetection capability for deep structuresVSAvoidimaging quality

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The detector is divided into multiple concentric segments, each detecting charged particles from specific angular ranges. This segmentation allows the system to process and analyze signals from different spatial zones separately, enabling discrimination of backscattered electrons based on their emission angles while maintaining high landing energy for deep structure penetration.

Inventive Principle:

Principle #1Segmentation

2Productivity

If high landing energy electron beams are used to increase penetration capability, then the momentum of backscattered electrons increases allowing them to escape and reach the detector, but the larger interaction volume causes degraded imaging quality

Engineering Contradiction:

Improvepenetration capabilityVSAvoidimaging quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Different concentric segments of the detector are optimized to detect charged particles with different emission angles and energy characteristics. The segmentation creates zones with specialized detection capabilities, allowing the system to selectively analyze backscattered electrons from specific regions while maintaining high landing energy for deep penetration.

Inventive Principle:

Principle #3Local quality

3Quantity of substance

If conventional detectors are used to collect backscattered electrons, then all emitted charged particles are collected, but discrimination of BSEs by energy levels is not achieved

Engineering Contradiction:

Improvecollection efficiency of charged particlesVSAvoidenergy level discrimination capability

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The detector surface is divided into multiple concentric segments that spatially resolve backscattered electrons based on their emission angles. This geometric segmentation, combined with the relationship between emission angle and energy, enables energy level discrimination while maintaining high collection efficiency for all emitted charged particles.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces traditional energy filtering mechanisms with a geometric segmentation approach. Instead of using mechanical or electromagnetic filters to separate electrons by energy, the system uses the spatial distribution of backscattered electrons on the segmented detector surface, where emission angle correlates with energy, to achieve energy discrimination.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enhances image resolution and throughput by effectively collecting and discriminating BSEs based on energy levels, providing high-quality images of semiconductor features with reduced beam exposure time.

Implementation Method 1

backscattered electrons (BSEs) that may allow BSEs to escape the sample material and reach the detector

Methodology Applied

Scientific EffectBackscattering: Scattering

Implementation Method 2

each segment of the plurality of concentric segments is configured to detect the emitted charged particles having a range of energy levels and a corresponding dominant energy level

Methodology Applied

Scientific EffectEnergy discrimination:

Data Source

PatentUS20260004991A1Systems and methods of energy discrimination of backscattered charged-particles

Publication Date: 2026.01.01 ASML NETHERLANDS BV

AI summary

Systems and methods of imaging a sample using a charged-particle beam apparatus are disclosed. The charged-particle beam apparatus may include a charged-particle source configured to generate primary charged particles, the primary charged particles forming a primary charged-particle beam along a primary optical axis, and a charged-particle detector comprising a plurality of con-centric segments of a charged-particle sensitive material configured to detect charged particles emitting from a sample after interaction of the primary charged-particle beam with the sample, wherein each segment of the plurality of concentric segments is configured to collect the emitted charged particles having a range of energy levels and a dominant energy level.