Pellicle Membrane with Crystalline Inclusions for EUV Lithography
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Solution Overview
Problem
EUV lithographic pellicles face challenges with high operating temperatures due to absorption of EUV radiation, leading to dewetting and island formation of emissive metallic layers, which reduces transmissivity and increases the risk of failure.
Innovation Solution
A pellicle membrane comprising a matrix with randomly distributed crystalline inclusions, such as molybdenum silicide, zirconium silicide, or tungsten silicide, which increases emissivity and reduces dewetting, allowing for higher power usage while maintaining mechanical strength and EUV transmissivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a continuous emissive metallic layer is applied to increase emissivity, then the operating temperature is reduced, but dewetting and island formation occur which reduces transmissivity and increases failure risk
Solution Approach 1:
The continuous metallic layer is segmented into discrete nanoscale inclusions distributed throughout the membrane. This segmentation prevents dewetting and island formation while maintaining sufficient emissivity through the collective effect of numerous small inclusions, thereby resolving the contradiction between temperature reduction and reliability.
Solution Approach 2:
Different regions of the pellicle membrane have different properties: the matrix provides mechanical strength and transmissivity, while the dispersed metallic inclusions provide localized emissivity enhancement. This local differentiation allows the membrane to achieve both low operating temperature and high reliability.
2Loss of energy
If the pellicle membrane is made thinner to increase transmissivity, then EUV transmissivity improves, but mechanical strength and reliability decrease
Solution Approach 1:
The pellicle membrane is constructed as a composite material combining a thin transparent matrix with dispersed metallic inclusions. The thin matrix (10-50 nm) ensures high EUV transmissivity, while the composite structure with embedded inclusions maintains mechanical strength and thermal stability, resolving the contradiction between transmissivity and strength.
3Temperature
If a thicker metallic layer is applied to increase emissivity, then operating temperature is reduced, but transmissivity decreases due to increased absorption
Solution Approach 1:
The metallic material is segmented into nanoscale inclusions rather than a continuous thick layer. This segmentation allows the membrane to achieve sufficient emissivity through the cumulative effect of many small inclusions while maintaining high transmissivity, as each inclusion is too small to cause significant absorption loss.
Solution Approach 2:
The scale parameter of the metallic phase is changed from continuous/thick to discrete/nanoscale. This parameter change enables the membrane to achieve the desired emissivity without the transmissivity penalty associated with thicker continuous metallic layers.
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 effectively reduces operating temperatures, increases transmissivity, and enhances the pellicle's ability to withstand harsh EUV lithographic conditions, reducing the need for frequent replacements and maintaining imaging performance.
Implementation Method 1
the inclusions... increases emissivity and reduces dewetting, allowing for higher power usage while maintaining mechanical strength and EUV transmissivity
Implementation Method 2
EUV lithographic pellicles face challenges with high operating temperatures due to absorption of EUV radiation
Data Source
AI summary
A pellicle membrane for a lithographic apparatus, the membrane including a matrix including a plurality of inclusions distributed therein. A method of manufacturing the pellicle membrane, a lithographic apparatus including the pellicle membrane, a pellicle assembly for use in a lithographic apparatus including the membrane, as well as the use of the pellicle membrane in a lithographic apparatus or method.