EUV Pellicle Membrane With High-Bond-Energy Matrix for Outgassing
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Solution Overview
Problem
Existing pellicle membranes in EUV lithography apparatuses face challenges in maintaining high EUV transmissivity, thermal stability, and minimizing hydrogen-induced outgassing and contamination, particularly due to the migration and outgassing of silicon, which can lead to defects and damage in the lithographic apparatus.
Innovation Solution
A pellicle membrane comprising emissive crystals in a matrix with elements forming bonds having a bond dissociation energy of at least 447 kJ mol−1, such as silicon sulphide, oxide, or selenide, which reduces silicon migration and outgassing by incorporating stronger bonds, thereby enhancing EUV transmissivity and thermal emissivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pellicle membrane is made thinner to increase EUV transmissivity, then EUV transmissivity is improved, but mechanical strength and reliability deteriorate
Solution Approach 1:
The patent employs a composite membrane structure consisting of a silicon nitride layer and a silicon oxide layer. The silicon nitride layer provides high EUV transmissivity and mechanical strength, while the silicon oxide layer provides thermal stability and protects against hydrogen-induced outgassing. This composite structure resolves the contradiction by combining materials with complementary properties to achieve both high transmissivity and sufficient mechanical strength.
2Reliability
If the pellicle membrane is made thinner to increase EUV transmissivity, then EUV transmissivity is improved, but resistance to hydrogen-induced outgassing deteriorates
Solution Approach 1:
The patent uses a composite structure where the silicon oxide layer specifically addresses hydrogen-induced outgassing. The silicon oxide layer has low hydrogen absorption and releases trapped hydrogen slowly, preventing the harmful effects of outgassing while allowing the silicon nitride layer to provide high EUV transmissivity.
3Productivity
If higher power is used to increase productivity, then productivity is improved, but thermal stability and contamination resistance deteriorate
Solution Approach 1:
The patent employs a composite structure where the silicon oxide layer provides thermal stability and resistance to thermal degradation. The silicon nitride layer provides high EUV transmissivity and mechanical strength. Together, they enable the membrane to withstand higher power levels without deforming or releasing contamination, thus improving productivity while maintaining thermal stability.
4Device complexity
If conventional materials are used to maintain simplicity, then device complexity is reduced, but contamination and outgassing increase
Solution Approach 1:
The patent uses a composite structure of silicon nitride and silicon oxide layers. This composite material approach, while slightly more complex than single-material solutions, effectively reduces contamination and outgassing by combining the low-outgassing properties of silicon oxide with the high transmissivity and strength of silicon nitride, achieving better performance with acceptable complexity.
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 pellicle membranes with improved EUV transmissivity, reduced silicon outgassing, and increased thermal emissivity, allowing operation under higher powers while minimizing contamination and maintaining optical performance.
Implementation Method 1
a pellicle membrane comprising emissive crystals in a matrix containing at least one element which forms a chemical bond with silicon having a bond dissociation energy of at least 447 kJ mol−1 or at least 4.6 eV
Implementation Method 2
A lithographic apparatus which uses EUV radiation, being electromagnetic radiation having a wavelength within the range 4-20 nm
Implementation Method 3
increased thermal emissivity
Data Source
AI summary
A pellicle membrane including emissive crystals in a matrix containing at least one element which forms a chemical bond with silicon having a bond dissociation energy of at least 447 kJ mol−1. A method of manufacturing such a pellicle membrane, a pellicle assembly including such a pellicle membrane and a lithographic apparatus including such a pellicle assembly or pellicle membrane. Also the use of molybdenum silicon sulphide, oxide, selenide, or fluoride in a pellicle membrane. The use of such a pellicle membrane, pellicle assembly or lithographic apparatus in a lithographic apparatus or method.