EUV Pellicle Thermal Buffer Layer Design
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Solution Overview
Problem
EUV lithography apparatuses face issues with pellicle durability and thermal accumulation due to high-energy light, leading to membrane deformation and process degradation.
Innovation Solution
A pellicle design featuring thermal buffer layers with high emissivity, made of materials like carbon, graphene, or silicon carbide, to prevent thermal accumulation and enhance durability by effectively emitting thermal radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pellicle membrane is used to protect the reticle in EUV lithography, then the reticle is protected from external factors, but thermal accumulation occurs due to high-energy light passing through the membrane
Solution Approach 1:
A thermal buffer layer is introduced as an intermediary between the membrane and the reticle. This buffer layer has higher emissivity than the membrane, enabling it to effectively radiate away thermal energy generated by high-energy EUV light, thereby preventing thermal accumulation in the membrane while maintaining reticle protection.
Solution Approach 2:
The emissivity parameter of the pellicle structure is changed by adding a thermal buffer layer with higher emissivity than the membrane. This parameter change enables more efficient thermal radiation, converting the thermal energy from high-energy light into radiated energy that can be dissipated, thus resolving the thermal accumulation problem.
2Productivity
If the pellicle membrane is exposed to high-energy light, then lithography process continues, but the membrane deforms due to thermal accumulation
Solution Approach 1:
The thermal buffer layer serves as a mediator that absorbs and radiates thermal energy, preventing it from deforming the membrane. This allows the membrane to maintain its shape and optical properties even during continuous exposure to high-energy EUV light, ensuring lithography process continuity.
Solution Approach 2:
The thermal energy from high-energy light, which initially causes membrane deformation, is converted into a beneficial effect by the thermal buffer layer. The buffer layer's high emissivity transforms the harmful thermal accumulation into efficient thermal radiation, protecting the membrane from deformation while allowing continuous lithography operation.
3Reliability
If the pellicle is used in EUV lithography apparatus, then the optical pattern is protected, but the pellicle durability degrades due to thermal accumulation
Solution Approach 1:
The thermal buffer layer acts as a protective intermediary that shields the membrane from thermal damage. By having higher emissivity, it efficiently radiates thermal energy away, preventing the membrane from degrading due to repeated thermal cycling from high-energy EUV light exposure, thus extending pellicle lifespan while maintaining optical pattern protection.
Solution Approach 2:
The emissivity parameter is optimized by introducing the thermal buffer layer with higher emissivity than the membrane. This parameter change enables the pellicle to better manage thermal energy, reducing thermal stress and degradation, thereby extending the duration of action (lifespan) of the pellicle while maintaining its protective function.
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 pellicle design prevents membrane deformation and improves durability and process reliability by efficiently managing thermal radiation, maintaining consistent pattern accuracy and extending the pellicle's lifespan.
Implementation Method 1
the first thermal buffer layer is associated with a first emissivity, and the first emissivity is greater than an emissivity of the membrane
Data Source
AI summary
A pellicle for lithography processes, including extreme ultraviolet (EUV) lithography may mitigate thermal accumulation in a membrane of the pellicle. The pellicle includes a membrane and at least one thermal buffer layer on at least one surface of the membrane. An emissivity of the thermal buffer layer may be greater than an emissivity of the membrane. A carbon content of the thermal buffer layer may be greater than a carbon content of the membrane. Multiple thermal buffer layers may be on separate surfaces of the membrane, and the thermal buffer layers may have different properties. A capping layer may be on at least one thermal buffer layer, and the capping layer may include a hydrogen resistant material. A thermal buffer layer may extend over some or all of a surface of the membrane. A thermal buffer layer may be between at least two membranes.