Amorphous Capping Layer for EUV Lithography Mask Damage Resistance
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Solution Overview
Problem
Conventional EUV lithography masks with poly-crystalline capping layers are prone to damage during processing, leading to degraded lithography performance and shortened lifespan, increasing the cost of semiconductor fabrication.
Innovation Solution
An EUV lithography mask with an amorphous capping layer, formed using techniques such as substrate tuning and plasma treatment, is introduced to withstand processing damages and improve performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a poly-crystalline capping layer is used in EUV lithography masks, then the mask can be manufactured with conventional processes, but the capping layer becomes easily damaged during processing, degrading lithography performance and shortening mask lifespan
Solution Approach 1:
The patent changes the structural parameter of the capping layer from poly-crystalline to amorphous phase. This phase change eliminates grain boundaries and structural defects inherent in poly-crystalline materials, thereby significantly improving damage resistance during etching and cleaning processes while maintaining manufacturability through conventional deposition techniques
Solution Approach 2:
The patent creates a composite structure by combining the amorphous capping layer with the underlying multi-layer reflective structure. The amorphous phase of the capping layer acts as a protective composite that enhances overall mask durability without compromising the optical performance of the reflective layers below
2Reliability
If the capping layer is made more resistant to damage, then lithography performance is maintained, but the manufacturing process becomes more complex
Solution Approach 1:
The patent achieves improved reliability through a parameter change (phase structure) rather than adding complex structural elements. The amorphous capping layer maintains the same basic mask architecture while improving performance through material phase optimization, avoiding increased device complexity
Solution Approach 2:
The patent applies local quality improvement by modifying only the capping layer's phase structure while leaving the rest of the mask architecture unchanged. This targeted approach improves damage resistance without requiring complex changes to the overall device structure or manufacturing process
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 amorphous capping layer enhances lithography performance and extends the lifespan of the EUV mask, reducing fabrication costs by minimizing damage from etching and cleaning processes and preventing contamination from outgassing products.
Implementation Method 1
a capping layer which has an amorphous structure rather than a poly-crystalline structure
Data Source
AI summary
A multi-layer reflective structure is disposed over the substrate. An amorphous capping layer is disposed over the multi-layer reflective structure. The amorphous capping layer may contain ruthenium, oxygen, niobium, nitrogen, tantalum, or zirconium. An amorphous layer may also be disposed between the multi-layer reflective structure and the amorphous capping layer. The amorphous layer includes amorphous silicon, amorphous silicon oxide, or amorphous silicon nitride.