Photon-Driven Radical Cleaning for Mask Contamination Prevention
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Solution Overview
Problem
High-energy photons used in mask and wafer inspection systems can cause photon-induced contamination on critical surfaces, leading to undesirable growth of thin films that are difficult to remove and may result in damage, highlighting the need for a method to prevent or minimize contamination.
Innovation Solution
An inspection specimen cleaning system that uses a light source to provide photons in combination with a mixture of gases to form reactive free radicals, which dissociate contaminants on the surface, effectively pre- or post-cleaning the specimens to reduce contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-energy photons are used for inspection, then inspection capability is improved, but photon-induced contamination on surfaces increases
Solution Approach 1:
The system performs preliminary cleaning of the mask or wafer surface before inspection by generating reactive species that remove organic contaminants. This pre-cleaning step reduces the amount of contaminant available for photon-induced reactions during subsequent inspection, thereby preventing contamination while maintaining high-energy photon inspection capability.
Solution Approach 2:
The system uses the same high-energy photons that cause contamination to generate reactive species (free radicals) that clean the surface. By converting the harmful photons into a cleaning mechanism, the system eliminates the contamination problem while maintaining the inspection capability.
2Object-affected harmful factors
If conventional cleaning methods are used, then surface contamination is reduced, but cleaning effectiveness against photon-induced contaminants is insufficient
Solution Approach 1:
The system changes the cleaning mechanism from conventional mechanical or chemical cleaning to photon-driven chemical cleaning. By using high-energy photons to generate reactive species, the system achieves superior cleaning effectiveness against organic contaminants that are resistant to conventional cleaning methods.
Solution Approach 2:
The system replaces conventional mechanical or chemical cleaning systems with a photon-based cleaning system. High-energy photons generate reactive species that chemically break down and remove contaminants, providing more effective cleaning than mechanical methods while being suitable for delicate semiconductor surfaces.
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 significantly reduces photon-induced contamination by forming reactive free radicals that efficiently break down contaminants, preventing film growth and potential damage during the inspection process, allowing for effective cleaning of surfaces before or after inspection.
Implementation Method 1
The photons in combination with the mixture of gases form reactive free radicals to dissociate contaminate compounds on the surface of the inspection specimen
Data Source
AI summary
A method and apparatus for preventing or minimizing contamination on a critical surface is disclosed. The method and apparatus for preventing or minimizing contamination on the critical surface may be an integrated component of an inspection system, and the cleaning process may be applied prior to the inspection process (may be referred to as pre-cleaning) which may greatly reduce photon-induced contamination. In addition, the cleaning process in accordance with the present disclosure may also be applied upon completion of the inspection process (may be referred to as post-cleaning).