Charged Particle Beam Retraction to Prevent ROI Charging

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Solution Overview

Problem

Existing charged particle beam devices face challenges in accurately measuring length due to charging and damage caused by blanking, especially in scanning regions of semiconductor devices manufactured using EUV microfabrication techniques, where the charged particle beam crosses the scanning region during blanking.

Innovation Solution

A charged particle beam device equipped with a first deflector for scanning and a second deflector for retracting the beam, along with a computer system that determines the retraction direction or position based on the scanning direction to prevent the beam from crossing the scanning region during blanking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the charged particle beam is retracted using a fixed blanking direction, then the blanking function is achieved, but the scanning region becomes charged and damaged due to beam crossing

Engineering Contradiction:

Improveblanking functionVSAvoidcharging and damage of scanning region

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the blanking direction variable rather than fixed. The control unit dynamically adjusts the blanking direction based on the scanning direction of the charged particle beam, ensuring that the retraction path does not intersect with the scanning region. This dynamic adaptation prevents charging and damage while maintaining effective blanking functionality.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the charged particle beam is largely deflected for blanking, then the beam is successfully retracted from the sample, but measurement accuracy deteriorates due to charging effects

Engineering Contradiction:

Improvebeam retractionVSAvoidlength measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by directing the blanking operation locally away from the scanning region. By determining the scanning direction and setting the blanking direction accordingly, the system ensures that the large deflection required for effective blanking occurs in a direction that does not affect the scanning region. This localized approach maintains measurement precision while achieving reliable beam retraction.

Inventive Principle:

Principle #3Local quality

3Productivity

If the charged particle beam crosses the scanning region during blanking, then the blanking operation is completed, but the fine pattern suffers from damage and shrinkage

Engineering Contradiction:

Improveblanking operation efficiencyVSAvoidfine pattern dimensions

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies preliminary anti-action by proactively determining the scanning direction before performing blanking and pre-calculating a safe retraction path. The control unit sets the blanking direction in advance to prevent beam crossing with the scanning region, thereby preventing damage to fine patterns before it can occur.

Inventive Principle:

Principle #9Preliminary anti-action

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 solution effectively suppresses charging and damage in the scanning region, ensuring accurate measurements by optimizing the blanking direction and position relative to the scanning region.

Implementation Method 1

a first deflector (6) configured to scan a region of interest with a beam (2) emitted from a beam source (1)

Methodology Applied

Scientific EffectCharged particle beam deflection: Lorentz Force

Implementation Method 2

an electron beam is retracted from the sample by largely deflecting the charged particle beam using an electric field or a magnetic field

Methodology Applied

Scientific EffectCharged particle beam deflection: Lorentz Force

Data Source

PatentUS20230317399A1Charged Particle Beam Device

Publication Date: 2023.10.05 HITACHI HIGH TECH CORP

AI summary

The invention is directed to suppress charge of a region of interest or damage in the region of interest caused by blanking. A charged particle beam device includes: a deflector configured to scan a region of interest with a beam emitted from a beam source; a second deflector configured to retract the beam to outside of the region of interest after scanning the region of interest with the beam; and one or more computer systems including one or more processors configured to execute a program stored in a storage medium, in which the one or more computer systems determine a retraction direction or a retraction position of the beam (Step S402) based on a scanning direction of the beam in the region.