Pellicle Membrane Metal Silicide Crystals EUV Transmissivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current pellicle membranes in EUV lithographic apparatuses face challenges in achieving high EUV transmissivity and low operating temperatures while maintaining structural integrity, as they tend to absorb excessive radiation, leading to increased temperatures and potential degradation.
Innovation Solution
A pellicle membrane comprising a population of metal silicide crystals in a silicon-based matrix with enhanced emissivity, where the crystals are aligned perpendicular to the surface and have diameters of 30 nm or less, and optionally doped with boron, phosphorus, or yttrium, to improve emissivity and mechanical strength, and a multi-layer structure with silicon molybdenum alloy layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the pellicle membrane is made thinner to increase EUV transmissivity, then transmissivity is improved, but mechanical strength and structural integrity deteriorate
Solution Approach 1:
The pellicle membrane employs a composite structure consisting of a silicon-based matrix embedded with metal silicide nanocrystals (such as molybdenum silicide, tungsten silicide, or titanium silicide). This composite material configuration enables the membrane to achieve high EUV transmissivity while maintaining adequate mechanical strength through the synergistic properties of the matrix and dispersed nanocrystals.
Solution Approach 2:
The metal silicide nanocrystals are distributed locally throughout the silicon-based matrix at controlled concentrations and sizes (average diameter of 1-50 nm). This local distribution of functional elements optimizes both transmissivity and mechanical properties by concentrating strengthening phases where needed while maintaining overall membrane thinness and transparency to EUV radiation.
2Power
If the pellicle membrane absorbs more EUV radiation to increase operating temperature, then source power handling is improved, but membrane degradation and lifetime deteriorate
Solution Approach 1:
The emissivity of the pellicle membrane is modified by incorporating metal silicide nanocrystals with specific electromagnetic properties. These nanocrystals alter the thermal radiation characteristics of the membrane, enabling it to emit absorbed EUV energy more efficiently as thermal radiation, thereby controlling operating temperature and preventing excessive heat accumulation that would lead to degradation.
Solution Approach 2:
The metal silicide nanocrystals convert the harmful effect of absorbed EUV radiation (which would otherwise cause excessive heating and degradation) into beneficial thermal radiation emission. By enhancing emissivity through the nanocrystal incorporation, the membrane efficiently radiates away absorbed energy, transforming potential damage into a controlled thermal management mechanism.
3Temperature
If dopants are added to increase emissivity and reduce operating temperature, then thermal management is improved, but chemical composition complexity increases
Solution Approach 1:
Dopants such as boron, phosphorus, or nitrogen are incorporated into the silicon-based matrix at controlled concentrations to modify the emissivity of the pellicle membrane. These dopant additions change the electrical and thermal properties of the silicon matrix, enabling efficient thermal radiation emission while maintaining a relatively simple overall chemical composition compared to alternative material systems.
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 provides a pellicle membrane with high EUV transmissivity and low operating temperatures, enabling the use of higher source powers while maintaining mechanical strength and preventing degradation, by optimizing crystal structure and composition without altering the chemical composition.
Implementation Method 1
the pellicle membrane has an emissivity of 0.3 or more... reducing the amount of EUV radiation absorbed by the pellicle may decrease the operating temperature of the pellicle
Implementation Method 2
optionally doped with boron, phosphorus, or yttrium, to improve emissivity and mechanical strength
Data Source
AI summary
A pellicle membrane includes a population of metal silicide crystals in a silicon-based matrix, wherein the pellicle membrane has an emissivity of 0.3 or more. Also a method of manufacturing a pellicle membrane, a pellicle assembly, a lithographic apparatus comprising such a pellicle membrane or pellicle assembly. Also the use of such a pellicle membrane, pellicle assembly, or lithographic apparatus in a lithographic apparatus or method.