Pellicle Membrane Recesses for EUV Light Transmission
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Solution Overview
Problem
The existing pellicle membranes used in EUV exposing technology for semiconductor and LCD device manufacturing suffer from high light absorption and mechanical fragility due to their thin thickness, which leads to reduced productivity and increased risk of damage from pressure differences.
Innovation Solution
A pellicle membrane with a multi-stack structure of light transmission layers, including recesses and openings, is designed to reduce EUV light absorption and enhance mechanical properties. The recesses and openings help buffer pressure differences, preventing damage and extending the membrane's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the membrane thickness is reduced to increase EUV light transmissivity, then light transmission is improved, but mechanical strength and durability deteriorate
Solution Approach 1:
The patent employs a multi-layer composite membrane structure where different layers have different thicknesses and material properties. The first light transmission layer has a first thickness and the second light transmission layer has a second thickness, creating a composite structure that optimizes both EUV light transmission and mechanical strength. This composite approach allows the membrane to achieve high transmissivity while maintaining durability against pressure differences.
Solution Approach 2:
The membrane is divided into multiple light transmission layers with different thicknesses rather than using a single uniform layer. This segmentation allows each layer to contribute differently to the overall performance - some layers optimized for light transmission and others for mechanical support, resolving the contradiction between thinness for transmission and thickness for strength.
2Productivity
If the membrane thickness is reduced to decrease light absorption, then productivity is improved, but susceptibility to pressure difference damage increases
Solution Approach 1:
The composite multi-layer structure provides both high light transmission (improving productivity) and enhanced mechanical strength (improving reliability). The varying thicknesses and material compositions across layers create a system that is both thin enough for high EUV transmission and strong enough to withstand pressure differences during handling and processing.
Solution Approach 2:
By segmenting the membrane into multiple layers with different thickness characteristics, the design achieves optimal balance between light transmission for productivity and structural integrity for reliability. The segmented structure prevents the membrane from being too thin and vulnerable while maintaining sufficient thickness for high transmission.
3Illumination intensity
If a thin membrane is used to avoid mask contamination, then EUV light transmission is improved, but the membrane becomes more prone to damage and wrinkle formation
Solution Approach 1:
The composite multi-layer membrane structure provides enhanced mechanical strength compared to a single thin layer, reducing susceptibility to damage and wrinkle formation while maintaining high EUV light transmission. The layered composite structure distributes mechanical stress more effectively, preventing the harmful effects that plague thin single-layer membranes.
Solution Approach 2:
The segmentation into multiple layers with different thicknesses creates a structure that is both thin enough for high EUV transmission and thick enough to resist damage and wrinkle formation. The segmented architecture provides internal structural support that prevents the membrane from becoming vulnerable despite its overall thinness.
Data Source
AI summary
A pellicle assembly may include a pellicle membrane and a pellicle border. The pellicle membrane may include at least one recess and at least one opening. The at least one recess may extend from an upper surface or a lower surface of the pellicle membrane. The at least one opening may penetrate from the upper surface to the lower surface of the pellicle membrane. The pellicle border may support the pellicle membrane.