Silver Seed Patterning for Uniform Nanoscale Interconnects
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Solution Overview
Problem
Current photolithography processes using extreme ultraviolet (EUV) light face challenges with non-uniform illumination and size variations due to unstable high power sources, and the use of sputtered copper in interconnects limits further reduction in feature size due to its grain size greater than 20 nm.
Innovation Solution
The method employs gamma ray radiation to pattern a light-sensitive silver precursor layer, reducing silver ions to form silver seed structures, which can be used as metal electrodes or etch masks, offering better resolution and uniformity by generating silver structures with smaller grain sizes and improved conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If EUV photolithography is used to pattern semiconductor devices, then resolution is improved, but illumination uniformity deteriorates due to unstable high power sources
Solution Approach 1:
The patent changes the wavelength parameter of radiation from EUV range to gamma ray range (0.01-10 nm), which fundamentally alters the interaction mechanism with the silver precursor layer. This parameter change enables achieving both high resolution and uniform illumination by using gamma rays that can penetrate deeper and provide more uniform exposure across the substrate area.
Solution Approach 2:
The patent replaces the mechanical/optical EUV light source system with a gamma ray radiation system. This substitution eliminates the instability issues associated with high power EUV sources while maintaining and improving pattern resolution through the different physical mechanism of gamma ray interaction with matter.
2Reliability
If sputtered copper is used in interconnects, then conductivity is improved, but feature size reduction is limited due to grain size greater than 20 nm
Solution Approach 1:
The patent changes the material parameter from copper to silver, and changes the grain size parameter through gamma ray induced deposition. This results in silver structures with grain sizes below 20 nm while maintaining high conductivity, thus resolving the contradiction between conductivity and feature size reduction.
Solution Approach 2:
The patent replaces the sputtering deposition method with gamma ray induced chemical reduction and deposition. This substitution enables precise control of grain size and feature dimensions at the nanoscale, overcoming the 20 nm limitation of sputtered copper while achieving the desired conductivity.
3Reliability
If gamma ray radiation is used to pattern silver precursor layer, then pattern uniformity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses a silver precursor layer as an intermediary material that converts gamma ray radiation into visible silver patterns. This intermediary approach simplifies the manufacturing process by enabling direct patterning without complex multi-step processes, while achieving superior uniformity through the photochemical reduction mechanism.
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 enhances pattern uniformity and reduces device performance variations, allowing for further reduction in feature sizes and improved integration density in semiconductor devices.
Implementation Method 1
exposing portions of the silver precursor layer to a radiation. The radiation causes a reduction of silver ions in the irradiated portions of the silver precursor layer
Data Source
AI summary
A method for forming a semiconductor structure is provided. The method includes depositing a hard mask layer over a substrate. The method further includes depositing a silver precursor layer over the hard mask layer. The method further includes exposing portions of the silver precursor layer to a radiation, the radiation causing a reduction of silver ions in the irradiated portions of the silver precursor layer. The method further includes removing non-irradiated portions of the silver precursor layer, resulting in a plurality of silver seed structures.