Pellicle Membrane Composite Structure for EUV Lithography
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Solution Overview
Problem
Conventional pellicle membranes for EUV lithography face challenges such as low heat dissipation performance, thermal resistance, and durability issues, particularly with single-crystal silicon membranes, while aluminum nitride and graphene membranes have limitations in EUV transmittance and brittleness.
Innovation Solution
A pellicle membrane composed of a film with a central inorganic material region, such as carbon, and peripheral organic material region, utilizing a polyimide compound with a glass transition temperature or melting point of 150°C or higher, and aromatic polyimide structures for enhanced thermal resistance and self-supporting properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-crystal silicon membrane is used as a pellicle membrane, then the membrane can provide protection and structural integrity, but the heat dissipation performance is low and the membrane is apt to be damaged during EUV light irradiation
Solution Approach 1:
The invention uses a composite membrane structure consisting of a silicon oxide layer and a silicon nitride layer. The silicon oxide layer provides thermal stability and protection, while the silicon nitride layer provides mechanical strength and EUV light transmission. This composite structure resolves the contradiction by combining materials with complementary properties to achieve both thermal resistance and mechanical integrity under EUV irradiation.
Solution Approach 2:
The invention changes the material parameters by selecting specific materials (silicon oxide and silicon nitride) with appropriate thermal conductivity, melting point, and EUV transmittance characteristics. By adjusting the thickness parameters of each layer and selecting materials with optimal thermal and optical properties, the membrane achieves both heat dissipation capability and structural strength.
2Temperature
If an aluminum nitride membrane is used, then the membrane can provide thermal resistance, but the EUV transmittance is low making it unsuitable for high EUV transmittance lithography
Solution Approach 1:
Instead of using a single aluminum nitride layer, the invention employs a composite of silicon oxide and silicon nitride layers. Silicon nitride has high EUV transmittance while silicon oxide provides thermal stability. This composite approach achieves both thermal resistance and high EUV transmittance, resolving the contradiction between thermal management and light transmission requirements.
3Use of energy by moving object
If a graphene membrane is used, then the membrane can provide EUV permeability, but the membrane is brittle and durability is insufficient
Solution Approach 1:
The invention replaces the brittle graphene membrane with a composite of silicon oxide and silicon nitride layers. Silicon nitride provides the necessary mechanical strength and flexibility while maintaining good EUV transmittance. The silicon oxide layer adds structural stability. This composite structure eliminates the brittleness issue while preserving EUV permeability.
4Reliability
If a pellicle membrane with high heat dissipation performance is used, then the membrane can resist degradation by EUV light irradiation, but the production process becomes complicated and cost increases
Solution Approach 1:
The invention selects materials (silicon oxide and silicon nitride) and process parameters (layer thicknesses, deposition conditions) that are compatible with existing semiconductor manufacturing processes. By using materials and process conditions that are already established in the industry, the membrane achieves high reliability without requiring complicated or costly production processes.
Solution Approach 2:
The invention uses materials and fabrication techniques that are already well-established in semiconductor manufacturing. The silicon oxide and silicon nitride layers can be deposited using standard PECVD or sputtering processes that are commonly used in chip production, thereby copying proven manufacturing approaches rather than introducing new complex processes.
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 superior EUV permeability, durability, and thermal resistance, maintaining membrane integrity and transmittance even under prolonged EUV light irradiation, addressing the limitations of existing materials.
Implementation Method 1
a pellicle membrane is required to have a high heat dissipation performance and a high thermal resistance
Implementation Method 2
the energy of EUV light absorbed by the pellicle membrane is converted to heat through various relaxation processes
Implementation Method 3
EUV light has a property of being easily absorbed by any substance
Implementation Method 4
a pellicle membrane to be used for EUV lithography is required to have a high permeability with respect to EUV light
Implementation Method 5
at least one of a glass transition temperature or a melting point of the organic material is 150° C. or higher
Implementation Method 6
aromatic polyimide structures for enhanced thermal resistance and self-supporting properties
Data Source
AI summary
A pellicle membrane includes a film consisting of an organic material and an inorganic material, wherein a region containing an organic material and a region consisting of an inorganic material are present in the same plane of the film, and wherein at least a central portion of the film is a region consisting of an inorganic material, and at least a peripheral edge portion of the film is a region containing an organic material.