EUV Lithography Pellicle with Crystalline Silicon and Graphene Layers
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Solution Overview
Problem
Current EUV lithography pellicles face challenges in achieving high EUV transmittance while maintaining excellent mechanical properties, particularly in large area coverage and simplified manufacturing processes.
Innovation Solution
A pellicle film with a multilayer thin film structure heterojunctioned with crystallized silicon (c-Si) and graphene layers, manufactured using electron beam irradiation to form a continuous layer without μm-sized grain boundaries, is developed. This structure is supported by a frame and bonded using a binder layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the thickness of Si material is reduced to improve EUV transmittance, then transmittance increases, but mechanical properties are degraded
Solution Approach 1:
The patent applies composite materials by combining SiC and SiN layers to create a pellicle film that achieves both high EUV transmittance and sufficient mechanical strength. The SiC layer provides structural support while the SiN layer enhances transmittance, creating a synergistic composite structure that resolves the contradiction between thickness reduction for transmittance and maintaining mechanical properties.
2Strength
If candidate materials such as SiC, SiN, and CNT are used to supplement mechanical strength, then mechanical properties improve, but EUV transmittance or required area is not satisfied
Solution Approach 1:
The patent applies local quality by assigning different functional characteristics to different layers: the SiC layer is optimized for mechanical strength and structural support, while the SiN layer is optimized for high EUV transmittance. This localized functional differentiation allows each material to excel at its specific function while contributing to the overall performance of the composite pellicle film.
3Ease of manufacture
If existing pellicle materials are used, then manufacturing process is established, but transmittance suitable for mass production has not been achieved
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness parameters of each layer (SiC layer at 10-50 nm and SiN layer at 5-20 nm) to achieve the desired balance between mechanical strength and EUV transmittance. By carefully controlling these dimensional parameters, the patent enables mass production of pellicles with transmittance of 70% or more while maintaining sufficient mechanical properties.
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 pellicle achieves high EUV transmittance and mechanical strength, ensuring durability against EUV exposure and the ability to withstand pressure differences in high vacuum environments, while also simplifying the manufacturing process for large-area pellicle production.
Implementation Method 1
crystallizing the amorphous silicon layer with changing the amorphous silicon layer to a c-Si layer while a surface of the amorphous silicon layer is heated through irradiation of an electron beam thereto and the heat is diffused downward
Implementation Method 2
the heat is diffused downward
Implementation Method 3
diffusing carbon of the carbon layer by making the carbon of the carbon layer come up to an interface of the c-Si/metal catalyst layers through the metal catalyst layer, and then making the come-up carbon form a graphene at the interface
Data Source
AI summary
Disclosed are: a pellicle for EUV lithography, which simultaneously satisfies the high transmittance and mechanical strength of crystalline silicon and can be manufactured in a large area, and a method for manufacturing the same.