Nanowire Photomask Pellicle for EUV Transmittance and Rigidity
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Solution Overview
Problem
Existing photolithography techniques, particularly in EUV photolithography, face challenges in achieving robustness and performance due to the limitations of current photomask pellicle materials, which struggle with high EUV transmittance, efficient heat dissipation, and durability against environmental factors.
Innovation Solution
A photomask pellicle with a membrane formed from a network of nanowires that provides high EUV transmittance, sufficient rigidity, and ductility, reducing sagging effects, and is compatible with existing semiconductor manufacturing processes, enhancing yield and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a solid thin film membrane is used in the pellicle, then the pellicle structure is simple and easy to manufacture, but the EUV transmittance is insufficient and heat dissipation is poor
Solution Approach 1:
The patent employs a porous nanowire network membrane instead of a solid thin film. The nanowires are arranged with controlled spacing to create a porous structure that allows EUV light to pass through while providing sufficient mechanical support. This porous configuration significantly improves EUV transmittance compared to solid films, while the nanowire material composition enables effective heat dissipation through thermal conduction pathways.
Solution Approach 2:
The pellicle membrane is constructed using composite materials at the nanoscale, combining nanowires made from materials with high EUV transmittance and good thermal conductivity. The composite nanowire network integrates multiple material properties to simultaneously achieve high transmittance, effective heat dissipation, and adequate mechanical strength, resolving the limitations of single-material solid films.
2Reliability
If the pellicle membrane is made thinner to improve EUV transmittance, then light transmission increases, but the membrane becomes less rigid and sags more
Solution Approach 1:
The porous nanowire network provides a unique solution where the open structure allows light transmission without requiring a continuous solid layer. The nanowires can be made extremely thin while maintaining rigidity through their high aspect ratio and the collective support of the network structure, preventing sagging while maximizing EUV transmittance.
Solution Approach 2:
The patent transitions from a two-dimensional solid film to a three-dimensional nanowire network structure. This dimensional change allows the membrane to achieve both high transmittance (through the open 3D structure) and sufficient rigidity (through the vertical dimension of the nanowires and their interconnections), eliminating the trade-off between thinness and structural integrity.
3Reliability
If a nanowire network membrane is used instead of a solid film, then EUV transmittance and heat dissipation improve, but the manufacturing process becomes more complex
Solution Approach 1:
The nanowire network membrane is designed to be self-supported, eliminating the need for additional solid support layers or complex assembly structures. The nanowires self-organize into a stable network that provides both mechanical integrity and functional performance, simplifying the overall device architecture despite the advanced nanofabrication processes required.
Solution Approach 2:
The nanowire network simultaneously performs multiple functions: it provides mechanical support as a membrane, enables high EUV transmittance through its porous structure, and facilitates heat dissipation through thermal conduction pathways. This multi-functionality consolidates what would otherwise require separate components, reducing overall system complexity despite the sophisticated nanowire fabrication process.
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 nanowire-based pellicle effectively protects the photomask from contaminants, maintains EUV light transmission, and extends service lifetime while reducing manufacturing costs, addressing the limitations of existing pellicle materials.
Implementation Method 1
provides high EUV transmittance
Implementation Method 2
sufficient rigidity, and ductility, reducing sagging effects
Implementation Method 3
effectively protects the photomask from contaminants
Data Source
AI summary
A first capping layer is deposited over a substrate. A network of nanowires is grown over the first capping layer. A second capping layer is deposited over the network of nanowires. The substrate is etched to form a frame of a pellicle. The first capping layer and the second capping layer are patterned to form a membrane of the pellicle, wherein the patterning reduces a material of the first capping layer and the second capping layer to form a coating on the nanowires.