EUV Lithography Mask Barrier Layer Design
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Solution Overview
Problem
The semiconductor industry faces challenges in manufacturing high-resolution lithography masks, particularly in extreme ultraviolet (EUV) lithography, due to issues such as image distortion, inter-diffusion of layers, and degradation of EUV light intensity, which affect the complexity and efficiency of processing and manufacturing.
Innovation Solution
A lithography mask is fabricated using a substrate with a reflective multilayer, a barrier layer, and an absorber layer, where the barrier layer prevents inter-diffusion and is selectively etched to form the final pattern, and the absorber layer absorbs radiation, with a thickness of the barrier layer being less than or equal to 10 nm to minimize EUV light absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a barrier layer is added to prevent inter-diffusion, then layer stability is improved, but device complexity increases
Solution Approach 1:
A barrier layer is introduced as an intermediary component between the reflective multilayer and the absorber layer. This barrier layer prevents inter-diffusion between the adjacent layers, maintaining layer stability and composition integrity during EUV lithography processing.
Solution Approach 2:
The lithography mask employs a composite structure consisting of multiple functional layers including a reflective multilayer, a barrier layer, and an absorber layer. Each layer is composed of specific materials selected for their optical and structural properties, creating a composite system that achieves the desired performance.
2Reliability
If the barrier layer thickness is increased to improve coverage, then protection is improved, but EUV light absorption increases
Solution Approach 1:
The thickness of the barrier layer is precisely controlled and optimized to be between 0.1 nm and 10 nm. This parameter optimization ensures that the barrier layer is sufficiently thick to prevent inter-diffusion and provide adequate protection, while remaining thin enough to minimize absorption of EUV light and maintain high reflectivity.
3Measurement precision
If EUV light intensity is increased to improve resolution, then measurement precision is improved, but image distortion increases
Solution Approach 1:
The barrier layer is deposited beforehand on the reflective multilayer to prevent inter-diffusion that could cause image distortion. Additionally, the optimized thin barrier layer design cushions against excessive EUV light absorption, allowing high-intensity EUV light to be used for improved resolution while minimizing the harmful effect of image distortion.
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 configuration minimizes image distortion, enhances EUV light reflectivity, and improves the manufacturing efficiency by preventing inter-diffusion and maintaining high reflectivity, thereby supporting the production of smaller and more complex semiconductor circuits.
Implementation Method 1
a substrate, a reflective multiplayer (ML) on the substrate
Implementation Method 2
an absorber layer over the barrier layer
Data Source
AI summary
A lithography mask includes a substrate, a reflective multilayer (ML) on the substrate, and a barrier layer on the reflective ML. The barrier layer includes at least one material selected from the group consisting of ruthenium nitride, hafnium oxide, aluminum nitride, boron carbide, boron nitride, and a combination thereof.