Graphite Pellicle Membrane for EUV Lithography
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Solution Overview
Problem
Conventional pellicles used in transmissive photolithography processes have low transmittance and durability issues when used in extreme ultraviolet (EUV) photolithography, as they are not suitable for EUV light, leading to reduced productivity and poor durability.
Innovation Solution
The development of pellicles with graphite layers, manufactured using chemical vapor deposition (CVD) processes, where a substrate is prepared, a membrane with a graphite layer is formed, separated, rinsed, and transferred onto a frame using specific solvents, and additional layers such as straining and capping layers are formed to enhance durability and transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional membrane is used in EUV photolithography, then the process can proceed, but the transmittance of EUV light is low and durability is poor
Solution Approach 1:
The patent changes the material composition parameter of the membrane from conventional materials to graphite, which fundamentally alters the optical and mechanical properties. Graphite provides both high EUV light transmittance and excellent durability, resolving the contradiction between these two parameters.
Solution Approach 2:
The patent employs graphite as a composite material structure on the membrane, combining the advantages of graphite's chemical stability and optical properties. This composite approach enables the membrane to simultaneously achieve high durability and high EUV light transmittance.
2Reliability
If a pellicle with high durability is used, then reliability improves, but productivity is reduced
Solution Approach 1:
By changing the membrane material to graphite, the pellicle achieves high durability without sacrificing productivity. The graphite membrane's superior properties allow for longer operational life and reduced maintenance, thereby improving overall productivity despite the enhanced durability features.
3Illumination intensity
If a graphite layer is formed on the membrane, then EUV light transmittance and durability are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The graphite layer is formed on the membrane during the initial manufacturing process using CVD technology. This preliminary action integrates the graphite layer formation into the base manufacturing flow, minimizing additional process steps and complexity while ensuring the membrane has the required optical and mechanical properties from the start.
4Ease of manufacture
If the membrane is separated from the substrate using selective solvents, then the membrane can be transferred to the frame, but additional rinsing and drying steps are required
Solution Approach 1:
Selective solvents are used as intermediary substances to facilitate the separation of the membrane from the substrate. These solvents selectively dissolve the bonding interface without damaging the membrane or frame, enabling easy transfer. The subsequent rinsing and drying steps remove residual solvent, completing the transfer process cleanly.
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 resulting pellicles exhibit high EUV light transmittance and improved physical durability, enhancing the stability and productivity of the EUV photolithography process while providing resistance to particle contamination and electrostatic forces.
Implementation Method 1
forming a membrane on the substrate by performing a chemical vapor deposition (CVD) process
Implementation Method 2
separating the membrane from the substrate in a first solvent
Data Source
AI summary
Provided is a method of manufacturing a pellicle. The method includes preparing a substrate, forming a membrane on the substrate by performing a chemical vapor deposition (CVD) process, separating the membrane from the substrate in a first solvent, rinsing the separated membrane in a second solvent, and transferring the separated membrane to a frame in a third solvent.