EUV Mask Pod Barriers for Reticle Contamination Containment
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Solution Overview
Problem
Existing EUV lithography systems face challenges in protecting photo masks (reticles) from external particulate matter and preventing contamination of the lithography system due to pellicle rupture, which can lead to defects in the pattern projected on semiconductor substrates.
Innovation Solution
An improved EUV mask pod design is introduced, featuring a reticle enclosure with a base and cover that form an internal space, secured by restraining mechanisms, and surrounded by concentric barriers that create a tortuous path to limit the passage of contaminants. Additionally, padding made of elastic material is disposed in gaps between the barriers and the enclosure surfaces to further impede particle movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a simple mask case is used to protect the photo mask, then the device complexity is reduced, but the protection effectiveness against particulate matter is insufficient
Solution Approach 1:
The patent implements a nested pod structure where an inner pod containing the reticle is placed inside an outer pod. The inner pod includes a reticle support structure with the reticle mounted on it, while the outer pod provides additional protection. This nested configuration enhances protection effectiveness against particulate matter while maintaining a manageable structural complexity through modular design.
Solution Approach 2:
The mask pod system is segmented into distinct functional components: the outer pod providing environmental protection, the inner pod providing reticle support and additional protection, and the pellicle providing direct reticle surface protection. This segmentation allows each component to be optimized for its specific function, improving overall protection effectiveness while enabling easier manufacturing and assembly.
2Object-affected harmful factors
If the photo mask is stored in a mask case, then protection from contamination is improved, but particle dispersion upon pellicle rupture cannot be prevented
Solution Approach 1:
The nested pod structure is designed to preemptively contain particles in case of pellicle rupture. The inner pod acts as a first containment barrier that would capture particles if the pellicle fails, preventing them from dispersing into the outer pod and lithography system. This preliminary protective measure addresses the potential failure mode before it can cause harm.
Solution Approach 2:
The outer pod serves as a cushioning containment structure that would absorb and contain particles if the inner pod or pellicle fails. This layered containment approach provides progressive protection, with each layer acting as a backup containment barrier to prevent particle dispersion into the lithography system.
Data Source
AI summary
A reticle enclosure includes a base including a first surface, a cover including a second surface and coupled to the base with the first surface facing the second surface. The base and the cover form an internal space that includes a reticle. The reticle enclosure includes restraining mechanisms arranged in the internal space and for securing the reticle, and structures disposed adjacent the reticle in the internal space. The structures enclose the reticle at least partially, and limit passage of contaminants between the internal space and an external environment of the reticle enclosure. The structures include barriers disposed on the first and second surfaces. In other examples, a padding is installed in gaps between the barriers and the first and second surfaces. In other examples, the structures include wall structures disposed on the first and second surfaces and between the restraining mechanisms.