EUV Substrate Inspection with Aperture-Based Point Source
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Solution Overview
Problem
Current extreme ultraviolet lithography systems face challenges in efficiently inspecting defects on EUV mask blanks due to complex and costly optics, which hinder the production of high-quality, defect-free masks necessary for shrinking semiconductor feature sizes.
Innovation Solution
An EUV substrate inspection system utilizing an EUV point source with an aperture or directed beam to reduce off-axis rays, combined with an EUV image sensor and image processor, enables focused illumination and detection of defects with enhanced sensitivity and accuracy, eliminating the need for complex optics and improving scanning speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex optics are used for EUV substrate inspection, then measurement precision is improved, but device complexity increases and manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates complex optical elements (mirrors, lens elements with multilayer coatings) from the inspection system. Instead of using traditional complex optics to focus and detect EUV light, the invention uses a simplified configuration with an EUV point source and direct detection, removing unnecessary optical components while maintaining defect detection capability.
Solution Approach 2:
The patent replaces expensive, complex optical components with simpler, more cost-effective alternatives. The simplified optics using aperture-based EUV point source and direct detection system reduces manufacturing costs and eliminates the need for expensive multilayer-coated mirrors and lens elements.
2Measurement precision
If complex optics are used for EUV substrate inspection, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes complex and expensive optical components (multilayer-coated mirrors, focal length elements) from the inspection system. The simplified design uses basic aperture structures and direct EUV detection, dramatically reducing manufacturing costs while preserving the ability to detect sub-20 nm defects.
Solution Approach 2:
The invention substitutes expensive optical components with inexpensive alternatives. The aperture-based EUV point source and direct detection system eliminates the need for costly multilayer coatings and precision optical elements, making the inspection system more affordable and easier to manufacture.
3Measurement precision
If traditional inspection optics are used, then measurement precision is maintained, but productivity decreases due to slower scanning speed
Solution Approach 1:
The patent eliminates complex optical focusing elements that slow down the inspection process. By using a simplified EUV point source configuration with aperture control and direct detection, the system achieves fast scanning speeds while maintaining sub-20 nm resolution, improving overall inspection productivity.
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 achieves sub-20 nm resolution and significantly reduces manufacturing costs by simplifying optics, enhancing defect detection sensitivity and accuracy, and expediting the inspection process.
Implementation Method 1
an EUV source directing EUV illumination through an aperture
Implementation Method 2
a light detector detecting mask illumination with reduced off axis rays reflected off from a substrate
Implementation Method 3
an aperture or directed beam to reduce off-axis rays
Data Source
AI summary
An extreme ultraviolet (EUV) substrate inspection system and method of manufacturing thereof, includes: an EUV source directing EUV illumination through an aperture; a light detector detecting mask illumination with reduced off axis rays reflected off from a substrate; and a computing device processing image data detected by the light detector.