Backup Fiducial Creation for Charged Particle Beam Positioning

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Charged particle beam systems face challenges in maintaining precise positional tracking due to beam drift caused by mechanical or thermal instabilities, leading to fiducial degradation and loss of accuracy in processing small structures.

Innovation Solution

The method involves creating multiple reference fiducials on a sample, where one fiducial is used to create additional fiducials as the primary fiducial degrades, allowing continuous positional tracking by expanding the image frame to include undamaged backup fiducials and recreating primary fiducials when necessary, thereby maintaining accurate beam positioning during processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the beam is repeatedly scanned across the region of interest for processing, then the productivity is improved, but the fiducial becomes damaged through etching and is no longer recognizable

Engineering Contradiction:

Improveprocessing throughputVSAvoidfiducial recognizability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The fiducial system is segmented into multiple backup fiducials (first backup, second backup, third backup) positioned at different locations. When the primary fiducial becomes damaged during repeated beam scanning, the system transitions to using backup fiducials, allowing continuous processing without interruption while maintaining positional tracking accuracy.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the image frame is expanded to include backup fiducials, then the positional tracking reliability is improved, but the area exposed to beam damage is increased

Engineering Contradiction:

Improvepositional tracking accuracyVSAvoidbeam-induced surface damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Multiple backup fiducials are pre-positioned at different locations around the region of interest before processing begins. This preliminary arrangement ensures that when the primary fiducial becomes damaged, a backup fiducial is already available for immediate use, maintaining positional tracking accuracy without requiring expansion of the image frame during processing.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If the primary fiducial is used for extended processing, then the manufacturing precision is maintained, but the fiducial degrades and accumulative errors occur

Engineering Contradiction:

Improvebeam positioning accuracyVSAvoidfiducial usable life

Core Design Contradiction:

Manufacturing precisionVSDuration of action of stationary object

Solution Approach 1:

The system continuously monitors the condition of the primary fiducial during processing. When the fiducial becomes damaged and is no longer recognizable, the system provides feedback to switch to a backup fiducial, ensuring that manufacturing precision is maintained throughout the entire processing operation without accumulative errors from fiducial degradation.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3101679B1Dynamic creation of backup fiducials

Publication Date: 2017.11.15 FEI CO

Figure 1A~1B
Figure 2A~2D
Figure 3A~3C

AI summary

Multiple reference fiducials (206, 208) are formed on a sample for charged particle beam facilties processing the sample. After one fiducial (206) is degraded by the charged particle beam, a second backup fiducial (208) is used to create one or more additional fiducials (216).