SnOx Hard Mask for EUV Lithography
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Solution Overview
Problem
Current photolithography processes face challenges in achieving small feature sizes due to the limitations of traditional organic chemically amplified resists in extreme ultraviolet (EUV) lithography, including low absorption coefficients and potential pattern collapse, necessitating improved EUV photoresist materials with increased absorbance and etch resistance.
Innovation Solution
The development of a SnOx thin film imaging layer terminated with alkyl groups that undergo tin-carbon bond cleavage upon EUV irradiation, allowing for the creation of chemically distinct regions, enhanced absorption of radiation, and reduced EUV dose requirements, using methods such as atomic layer deposition or chemical vapor deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional organic chemically amplified resists are used in EUV lithography, then the process is compatible with existing 193 nm UV lithography workflows, but the absorption coefficient is low and pattern collapse occurs
Solution Approach 1:
The patent changes the material composition parameters by transitioning from organic chemically amplified resists to inorganic SnOx-based imaging layers. This fundamental material parameter change enables high EUV absorption coefficients while maintaining compatibility with existing lithography workflows through standardized deposition and patterning processes.
Solution Approach 2:
The patent employs composite material structures by combining SnOx imaging layers with underlying adhesion layers and overlying hard mask layers. This multi-layer composite approach optimizes both the absorption properties of SnOx and the structural integrity required to prevent pattern collapse during etching.
2Strength
If conventional CAR materials are used to provide etch resistance, then etch protection is achieved, but the required thickness creates high aspect ratios at risk of pattern collapse
Solution Approach 1:
The patent utilizes thin film technology by implementing ultrathin SnOx imaging layers (5-20 nm) that function as both the primary EUV-absorbing layer and the etch resistance layer. This thin film approach eliminates the need for thick conventional resist layers, thereby reducing aspect ratios and preventing pattern collapse while maintaining sufficient etch protection.
Solution Approach 2:
The SnOx imaging layer serves multiple functions simultaneously: it acts as the EUV photoresist, provides etch resistance, and ensures adhesion to the substrate. This multi-functionality eliminates the need for separate thick resist and hard mask layers, reducing overall layer thickness and aspect ratio while maintaining pattern fidelity.
3Manufacturing precision
If EUV lithography is implemented to achieve smaller feature sizes, then resolution is improved, but light loss during patterning limits efficacy
Solution Approach 1:
The patent changes the optical parameters by introducing SnOx materials with high EUV absorption coefficients. This parameter change enables efficient utilization of EUV light energy, reducing light loss during patterning while achieving the required sub-20 nm feature size resolution through direct imaging or as a hard mask layer.
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 more sensitive and efficient EUV patterning with reduced pattern collapse and improved etch resistance, allowing for the production of semiconductor devices with smaller feature sizes by exploiting chemical differences between exposed and unexposed regions.
Implementation Method 1
SnOx thin film that is terminated with alkyl groups selected such that they will undergo tin-carbon bond cleavage, such as beta-hydride elimination, upon irradiation with EUV light
Implementation Method 2
undergo tin-carbon bond cleavage, such as beta-hydride elimination, upon irradiation with EUV light
Implementation Method 3
using methods such as atomic layer deposition or chemical vapor deposition
Data Source
AI summary
Imaging layers on the surface of a substrate may be patterned using next generation lithographic techniques, and the resulting patterned film may be used as a lithographic mask, for example, for production of a semiconductor device.