Tapered Mesh EUV Pellicle for Transmittance and Strength
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Solution Overview
Problem
Current EUV pellicle technologies face challenges in maintaining high transmittance of EUV light while ensuring sufficient physical strength, as existing materials are prone to attenuation and degradation, and reinforcement structures compromise light passage.
Innovation Solution
A taper-like mesh structure is designed for the EUV pellicle, where the width of the grid frame decreases with distance from the silicon thin film, optimizing the inclination angle to enhance light transmittance without compromising physical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a mesh structure is added to reinforce the silicon thin film, then the physical strength is improved, but the EUV light transmittance deteriorates due to increased blocking by the grid frames
Solution Approach 1:
The grid frame width is varied along its length, being narrower at portions farther from the silicon thin film and wider at portions closer to the film. This local variation in width creates different light-blocking characteristics at different positions, allowing the mesh structure to provide sufficient reinforcement while minimizing overall EUV light attenuation.
Solution Approach 2:
The invention changes the geometric parameter of the grid frame width along its length rather than maintaining a uniform width. By making the width variable (narrower at distal portions, wider at proximal portions), the structure optimizes the balance between mechanical strength and light transmittance, reducing the total blocking area while maintaining reinforcement effectiveness.
2Strength
If the mesh pitch is reduced to increase structure density, then the physical strength is improved, but the opening ratio decreases causing greater light attenuation
Solution Approach 1:
The variable width design of grid frames allows different sections of the mesh structure to serve different functions: wider frames near the film provide reinforcement, while narrower frames at distal portions minimize light blocking. This local differentiation enables the structure to achieve sufficient strength without requiring uniformly high density throughout.
Solution Approach 2:
The mesh structure employs asymmetric grid frame widths rather than uniform symmetry. The frames are deliberately designed with different widths at different positions (wider near the film, narrower farther away), creating an asymmetric configuration that optimizes both structural support and light transmission 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
This design improves EUV light transmittance while maintaining the necessary physical strength of the pellicle, allowing for increased exposure efficiency and reduced attenuation.
Implementation Method 1
a pellicle for EUV having an EUV transmitting film and a mesh structure which supports and reinforces the EUV transmitting film, wherein a shape of a longitudinal cross section of a grid frame, which constitutes the mesh structure, is taper-like
Data Source
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AI summary
A pellicle for EUV including a silicon film and a mesh work structure supporting the silicon film, and this pellicle is improved in that the grid frames of the mesh work structure are tapered in such a manner that the width of each grid frame lessens as the distance from the silicon film is increased.