EUV Resist Inhibition Layer for Selective Hard Mask Patterning
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Solution Overview
Problem
Current extreme ultraviolet (EUV) lithography techniques face challenges in achieving high resolution and reducing defectivity and cost due to limitations in photoresist mechanical strength and etch resistance, particularly at small feature sizes, leading to increased complexity in pattern transfer and defectivity.
Innovation Solution
The use of vapor-deposited resists and an inhibition layer in EUV lithography allows for selective deposition of hard masks on exposed resist areas, enhancing resolution and reducing defects by inhibiting unexposed areas during vapor phase deposition, and employing cyclical deposition methods like ALD to form uniform EUV-sensitive films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photoresist thickness is reduced to achieve smaller feature sizes, then resolution is improved, but etch resistance deteriorates
Solution Approach 1:
The patent divides the photoresist layer into multiple thinner sub-layers, each contributing to the overall pattern formation while maintaining adequate etch resistance. This segmentation allows the total thickness to be reduced for better resolution while each sub-layer provides sufficient mechanical support during etching.
Solution Approach 2:
The patent employs composite photoresist materials combining organic and inorganic components, or uses multi-material stack configurations, to achieve both high resolution at reduced thickness and sufficient etch resistance. The composite structure provides enhanced mechanical strength and etch barrier properties without increasing overall thickness.
2Manufacturing precision
If multiple patterning steps are used to achieve smaller features, then resolution is improved, but device complexity and defectivity increase
Solution Approach 1:
The patent applies preliminary surface modification treatments to the substrate or photoresist before lithography, such as self-aligned hard mask formation or surface energy modification, to enable direct single-step patterning at high resolution without requiring multiple iterative lithography steps.
Solution Approach 2:
The patent utilizes advanced lithography parameters including EUV wavelength optimization, variable dose exposure, and modified photoresist chemical composition to achieve high-resolution single-step patterning, eliminating the need for multiple patterning cycles.
3Manufacturing precision
If photoresist thickness is reduced to improve resolution, then feature size is decreased, but mechanical strength deteriorates causing pattern collapse
Solution Approach 1:
The patent applies local quality enhancement by providing targeted mechanical support structures at critical regions of the pattern, such as increased cross-linking density or additional support layers at pattern edges and corners, allowing thin photoresist to maintain structural integrity without increasing overall thickness.
Solution Approach 2:
The patent incorporates preliminary support structures or reinforcement layers formed before the lithography step, such as thin hard mask layers or adhesion promoters, that provide mechanical cushioning to the thin photoresist during development and etching, preventing pattern collapse.
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 definition of small features in a single exposure, improving resolution, reducing defectivity, and controlling costs by providing a robust and precise method for hard mask deposition, thus overcoming the limitations of traditional EUV lithography.
Implementation Method 1
Exposure of the EUV-sensitive film to EUV radiation can change the surface functionality
Implementation Method 2
the inhibition layer inhibits the unexposed resist areas versus the exposed resist areas with respect to vapor phase deposition of a hard mask
Implementation Method 3
depositing uniform EUV-sensitive films using a cyclical deposition method such as ALD
Data Source
AI summary
Structures, related methods, and related systems are disclosed. An embodiment of a structure comprises a resist and an inhibition layer. The EUV resist comprises exposed resist areas and unexposed resist areas. The inhibition layer inhibits the unexposed resist areas versus the exposed resist areas with respect to vapor phase deposition of a hard mask.