Simultaneous Double-Side Coating of Graphene Pellicles
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Solution Overview
Problem
Current methods for manufacturing pellicles, particularly those with hexagonal boron nitride (h-BN) coatings, face challenges such as damage during removal from support surfaces and thermal expansion mismatches, limiting the ability to coat both sides of graphene pellicles simultaneously, which affects their durability and performance in lithographic apparatuses.
Innovation Solution
The method involves using radiative heating to locally heat the pellicle within a chemical vapour deposition chamber, allowing for simultaneous deposition of a coating material like h-BN on both sides of the pellicle, reducing thermal stress and damage by focusing the heat directly on the pellicle rather than the supporting frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pellicle is coated on one side at a time using conventional methods, then the coating process is simpler, but the pellicle is damaged during removal from support surfaces and thermal expansion mismatches occur
Solution Approach 1:
The patent combines the coating of both sides of the pellicle into a single simultaneous process. The pellicle is suspended in a coating chamber and coating material is deposited on both sides at the same time, eliminating the need to remove and reattach the pellicle multiple times, thus preventing damage and thermal expansion mismatches.
Solution Approach 2:
The patent transitions from sequential one-sided coating to simultaneous two-sided coating by introducing a suspended configuration in three-dimensional space. The pellicle is held in a suspended state within the coating chamber, allowing coating material to access both sides simultaneously from opposite directions.
2Ease of manufacture
If the pellicle is heated uniformly with the supporting frame, then the heating process is simpler, but thermal expansion mismatches damage the pellicle
Solution Approach 1:
The patent applies heating locally to only the pellicle rather than uniformly heating both the frame and pellicle. The supporting frame remains at room temperature while the pellicle is selectively heated to the required temperature for coating, preventing thermal expansion mismatches between the frame and pellicle.
Solution Approach 2:
The heating system is segmented to independently control the temperature of the pellicle and the supporting frame. The frame is excluded from the heating zone, allowing separate thermal management where only the pellicle receives the necessary thermal energy for the coating process.
3Object-affected harmful factors
If the pellicle is made thinner to reduce contamination impact, then the protection effectiveness is improved, but the pellicle becomes more susceptible to free radical etching
Solution Approach 1:
The patent creates a composite structure by depositing hexagonal boron nitride (h-BN) coating on the graphene pellicle. The h-BN layer forms a protective composite material that provides both contamination protection and resistance to free radical etching, maintaining the thin profile while enhancing chemical stability.
Solution Approach 2:
The h-BN coating creates an inert protective environment on the surface of the thin pellicle. This coating layer acts as a barrier that prevents direct interaction between the thin pellicle material and free radical species in the atmosphere, reducing etching damage while maintaining the thin design for effective contamination protection.
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
This approach enables the reliable coating of both sides of pellicles with h-BN, enhancing their mechanical strength and resistance to free radical species, thereby extending their lifetime and improving their performance in high-temperature and high-radiation environments.
Implementation Method 1
locally heating the pellicle using radiative heating
Implementation Method 2
depositing a coating material simultaneously on both sides of the pellicle
Data Source
AI summary
A method of manufacturing a pellicle for a lithographic apparatus, the method including locally heating the pellicle using radiative heating, and depositing coating material simultaneously on both sides of the pellicle, and pellicles manufactured according to this method. Also disclosed is the use of a multilayer graphene pellicle with a double-sided hexagonal boron nitride coating in a lithographic apparatus.