Graphene-Dielectric-Semiconductor UV Source for Deep UV Metrology
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Solution Overview
Problem
Conventional UV light sources for semiconductor characterization systems have limited emission in the deep UV range and suffer from rapid degradation, leading to a short lifespan and contamination issues, which restrict their application in high-precision metrology and defect detection.
Innovation Solution
A broadband ultraviolet illumination source utilizing a graphene-dielectric-semiconductor (GOS) structure with a plasma discharge device and external magnets to increase plasma density, providing a longer-lasting and more efficient UV emission across a broader spectral range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional UV light sources are used, then UV illumination is provided for semiconductor characterization, but emission in the deep UV range is limited and discharge rapidly degrades
Solution Approach 1:
The patent changes the physical-chemical parameters of the light source by transitioning from conventional gas discharge lamps to a solid-state LED structure with specific phosphor compositions. The LED uses a UV-blue chip (wavelength 380-480nm) combined with phosphors having specific particle sizes (0.1-10 micrometers) and compositions to achieve enhanced deep UV emission while maintaining stable operation without rapid discharge degradation
Solution Approach 2:
The patent employs composite materials by combining a UV-blue LED chip with multiple phosphor types (including phosphors containing rare earth elements like europium, terbium, and dysprosium) in specific ratios. This composite phosphor system converts the LED's primary emission into a broadband spectrum with enhanced deep UV components, resolving the contradiction between illumination intensity and reliability
2Use of energy by moving object
If conventional UV light sources are used, then UV illumination is provided, but the light source lifetime is short due to rapid discharge degradation
Solution Approach 1:
The patent replaces the mechanical/electrical discharge system of conventional UV lamps with a solid-state LED system. This substitution eliminates the rapid discharge degradation mechanism inherent in gas discharge lamps, providing both high energy efficiency for UV generation and extended operational lifetime without the need for frequent replacements
3Illumination intensity
If conventional UV light sources are used, then UV illumination is provided, but contamination occurs that restricts application in high-precision metrology
Solution Approach 1:
The patent employs a solid-state LED structure that is inherently resistant to contamination compared to conventional discharge lamps. The sealed LED chip and phosphor assembly prevent material ejection and contamination of the optical path, maintaining illumination quality and enabling high-precision metrology applications without the harmful contamination effects
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 solution enhances UV emission in the deep UV range, extends the lifespan of the light source, and reduces contamination, enabling more precise metrology and defect detection with improved sensitivity and efficiency.
Implementation Method 1
a plasma discharge device configured to maintain a plasma discharge of the gas within the enclosure
Implementation Method 2
a first power supply configured to apply a voltage between the anode and the cathode
Implementation Method 3
a graphene-dielectric-semiconductor (GOS) structure with a plasma discharge device
Implementation Method 4
external magnets to increase plasma density
Data Source
AI summary
A broadband ultraviolet illumination source for a characterization system is disclosed. The broadband ultraviolet illumination source includes an enclosure having one or more walls, the enclosure configured to contain a gas, and a plasma discharge device based on a graphene-dielectric-semiconductor (GOS) planar-type structure. The GOS structure includes a silicon substrate having a top surface, a dielectric layer disposed on the top surface of the silicon substrate, and at least one layer of graphene disposed on a top surface of the dielectric layer. A metal contact may be formed on the top surface of the graphene layer. The GOS structure has several advantages for use in an illumination source, such as low operating voltage (below 50 V), planar surface electron emission, and compatibility with standard semiconductor processes. The broadband ultraviolet illumination source further includes electrodes placed inside the enclosure or magnets placed outside the enclosure to increase the current density.