Multilayer Reflective Film with Intermediate Diffusion Barrier
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Solution Overview
Problem
In extreme ultraviolet (EUV) lithography, the diffusion of atoms between low and high refractive index layers in multilayer reflective films reduces reflectance, affecting the accuracy and density of semiconductor devices, and existing technologies fail to effectively control the reflective surface to suppress this diffusion.
Innovation Solution
A substrate with a multilayer reflective film is developed, featuring alternately layered low and high refractive index layers with an intermediate layer containing nitrogen, carbon, or oxygen, which suppresses the diffusion of atoms between layers, maintaining a shallow effective reflective surface and enhancing reflectance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a multilayer reflective film is used in EUV lithography, then the reflectance is improved, but atom diffusion between layers occurs which reduces reflectance and affects manufacturing precision
Solution Approach 1:
A protective film is introduced as an intermediary layer between the low refractive index layer and the high refractive index layer in the multilayer reflective film. This protective film acts as a barrier that prevents atom diffusion between the adjacent layers while maintaining the optical performance. The protective film has a thickness of 0.1 nm to 10 nm and is positioned at the interface between layers to specifically address the diffusion problem without affecting the overall reflectance.
2Device complexity
If the multilayer film structure is simplified, then the device complexity is reduced, but the ability to suppress atom diffusion is weakened
Solution Approach 1:
The multilayer reflective film is segmented into distinct functional layers: a protective film layer, a low refractive index layer, and a high refractive index layer. This segmentation allows each layer to perform its specific function - the protective film prevents diffusion, while the other layers maintain optical performance. The segmentation approach enables the system to achieve both simplicity and reliability by assigning specific roles to each segment.
3Use of energy by moving object
If the film thickness is increased to improve reflectance, then the reflectance is improved, but the effective reflective surface becomes deeper which affects lithography accuracy
Solution Approach 1:
The thickness of the protective film is precisely controlled within the range of 0.1 nm to 10 nm to optimize its barrier function while minimizing its impact on the effective reflective surface depth. This parameter control ensures that the protective film is thick enough to prevent atom diffusion but thin enough to maintain the shallow effective reflective surface required for high-resolution lithography.
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 solution effectively suppresses the diffusion of atoms between refractive index layers, improving the reflectance and accuracy of EUV lithography, enabling higher density and accuracy in semiconductor devices by maintaining a shallow effective reflective surface.
Implementation Method 1
an intermediate layer containing nitrogen, carbon, or oxygen, which suppresses the diffusion of atoms between layers
Implementation Method 2
a multilayer reflective film for reflecting exposure light formed on a substrate
Data Source
AI summary
Provided is a substrate with a multilayer reflective film comprising a multilayer reflective film having a shallow effective reflective surface and capable of suppressing a phenomenon that atoms to be a material are diffused between a low refractive index layer and a high refractive index layer.A substrate with a multilayer reflective film comprises a substrate and a multilayer reflective film formed on the substrate, in which the multilayer reflective film comprises a multilayer film in which a low refractive index layer and a high refractive index layer comprising silicon (Si) are alternately layered, the multilayer reflective film further comprises at least one intermediate layer disposed between the low refractive index layer and the high refractive index layer, the multilayer reflective film comprises at least one additive element selected from nitrogen (N), carbon (C), and oxygen (O), and the content of the additive element in the multilayer reflective film is 40 atom % or less.