Charged Particle Optics Cleaning for Hydrocarbon Contamination Near Samples
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Solution Overview
Problem
Charged particle optical systems in semiconductor manufacturing face challenges with hydrocarbon contamination, particularly near the sample, where space is limited and existing cleaning methods like differential pumping are ineffective in preventing contamination across all components.
Innovation Solution
A charged particle assessment system with a cleaning device that supplies a cleaning medium in a flow towards a cleaning target, positioned downbeam of the optical system, to actively clean the surface, using a cleaning guide and stimulation energy to effectively remove contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If differential pumping is used to limit hydrocarbon contamination, then contamination on charged particle optical system components is reduced, but the effectiveness is limited close to the sample where space is insufficient
Solution Approach 1:
The patent extracts the cleaning function from the vacuum system by introducing a separate cleaning device that supplies cleaning medium (oxygen plasma) directly to the cleaning target. This allows contamination removal independent of the vacuum system's differential pumping capability, effectively addressing contamination in space-constrained areas near the sample
Solution Approach 2:
The patent introduces cleaning medium (oxygen plasma) as an intermediary substance to remove hydrocarbon contamination. The cleaning medium acts as a mediator between the cleaning device and the contaminated surfaces, enabling effective cleaning without requiring large space for traditional vacuum-based methods
2Object-affected harmful factors
If cleaning device is positioned to supply cleaning medium towards cleaning target from downbeam, then cleaning effectiveness is improved, but device complexity increases
Solution Approach 1:
The cleaning device is designed as a multi-functional component that integrates cleaning medium supply, flow guidance, and stimulation capabilities into a single system. This universal approach reduces overall device complexity compared to separate systems for each function while maintaining high cleaning effectiveness
Solution Approach 2:
The cleaning medium (oxygen plasma) is stimulated directly at or near the cleaning target, allowing the cleaning process to occur in-situ without requiring complex external cleaning mechanisms. The system serves itself by using the cleaning medium to clean the cleaning target and other components automatically during operation
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 system effectively reduces hydrocarbon contamination on charged particle optical system components, improving the accuracy and reliability of pattern inspection tools by maintaining a clean surface during semiconductor manufacturing.
Implementation Method 1
stimulate the cleaning medium at or near the cleaning target such that the cleaning medium cleans at least a portion of the surface of the cleaning target
Implementation Method 2
supply cleaning medium in a cleaning flow towards the cleaning target incident on the cleaning target so that the cleaning flow approaches the cleaning target from downbeam of the cleaning target
Data Source
AI summary
The embodiments of the present disclosure provide a charged particle assessment system for projecting a beam of charged particles towards a sample. The system comprises a sample holder configured to hold a sample; a charged particle optical system configured to project a beam of charged particles from a charged particle source downbeam towards the sample and comprising a cleaning target; and a cleaning device. The cleaning device is configured to supply cleaning medium in a cleaning flow towards the cleaning target incident on the cleaning target so that the cleaning flow approaches the cleaning target from downbeam of the cleaning target, and to stimulate the cleaning medium at or near the cleaning target such that the cleaning medium cleans at least a portion of the surface of the cleaning target.