Carbon Nanotube Interconnections via Ionic Liquid Deposition
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Solution Overview
Problem
The miniaturization of micro-electronic devices leads to increased current densities in copper-based interconnections, causing electromigration issues and incompatibility with structures smaller than 50 nm, as copper's resistivity increases and its suitability decreases, necessitating alternative materials like carbon nanotubes for vias and conduction lines, but controlling the density and size of carbon nanotubes is challenging with existing deposition techniques.
Innovation Solution
A method involving the deposition of ionic liquids with nanoparticles on a surface, followed by removal and heat treatment to control the size and distribution of nanoparticles, allowing for the growth of carbon nanotubes with improved structural homogeneity and conductivity, using ionic liquids for their low volatility, thermal stability, and ability to penetrate sub-micron structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper-based interconnections are used, then low electrical resistance and good resistance to electromigration are achieved, but miniaturization below 50 nm causes increased current densities and resistivity, making copper incompatible with smaller structures
Solution Approach 1:
The patent transitions from copper-based interconnections to carbon nanotube-based interconnections, fundamentally changing the material parameter to achieve compatibility with miniaturized structures below 50 nm while maintaining or improving electromigration resistance and electrical conductivity
Solution Approach 2:
The invention uses composite structures combining carbon nanotubes with other materials (such as metal nanoparticles as catalysts, dielectric materials, and conductive materials) to create interconnection structures that overcome the limitations of pure copper in miniaturized applications
2Temperature
If PECVD is used to synthesize carbon nanotubes, then application temperature is sufficiently low to be compatible with microelectronics architectures, but control over density and size of carbon nanotubes remains challenging
Solution Approach 1:
The patent applies preliminary actions by first depositing metal nanoparticle catalysts with controlled size and distribution before performing PECVD synthesis of carbon nanotubes. This preliminary catalyst deposition enables precise control over the subsequent nanotube density and size, overcoming the limitations of direct PECVD synthesis
Solution Approach 2:
The invention introduces metal nanoparticles as an intermediary catalyst between the PECVD process and the final carbon nanotube structure. These nanoparticles mediate the synthesis process, allowing indirect control over nanotube properties (density, size, distribution) while maintaining the low-temperature PECVD process
3Ease of manufacture
If metal nanoparticle catalysts are deposited to grow carbon nanotubes, then carbon nanotube growth is enabled, but density and size of nanoparticles are difficult to control, affecting carbon nanotube quality
Solution Approach 1:
The patent replaces traditional mechanical or chemical deposition methods for nanoparticle catalysts with electrical field-based deposition. By applying an electrical field during nanoparticle deposition, precise control over nanoparticle density, size, and distribution is achieved, enabling subsequent controlled growth of high-quality carbon nanotubes
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 method enables precise control over the size and dispersion of carbon nanotubes, enhancing the structural homogeneity and conductivity of interconnections, addressing the limitations of existing techniques and improving performance in micro-electronic devices.
Implementation Method 1
using ionic liquids for their low volatility, thermal stability, and ability to penetrate sub-micron structures
Implementation Method 2
followed by removal and heat treatment to control the size and distribution of nanoparticles
Implementation Method 3
growing carbon nanotubes from said deposited nanoparticles
Data Source
AI summary
A method for making electrical interconnections of carbon nanotubes, including a) depositing an ionic liquid including nanoparticles of at least one suspended electrically conducting material, covering at least one surface of an element configured to be used as a support for carbon nanotubes, b) forming a deposit of the nanoparticles at least against the surface of the element, c) removing the remaining ionic liquid, d) growing carbon nanotubes from the deposited nanoparticles, and further including between the c) removing the remaining ionic liquid and the d) growing carbon nanotubes, passivating the deposited nanoparticles not found against the surface of the element.