Methods to Fabricate Densified Carbon Nanotube Thin Films and Structures

Individual carbon nanotubes have already exhibited excellent properties such as high electrical conductivity, high Young’s modulus and a high thermal conductivity. However, for practical applications, dense bundles of carbon nanotubes must be used. Vertically aligned dense carbon nanotube films by CVD have already been demonstrated and can provide a good template. However, due to their low film density, strength, and electrical conductivity, vertically aligned dense carbon nanotube films have not been successfully integrated into microelectronic devices.

Currently, carbon nanotube applications are based on carbon nanotube membranes or carbon nanotube composites. To utilize these membranes or composites, tedious processes such as filtration, purification, and dispersion are involved, which are not compatible with current silicon technologies. In addition, these membranes or composites usually lack anisotropic properties originating from carbon nanotube structures.

Description

• Methods to fabricate densified carbon nanotube thin films and structures

• Methods to fabricate densified vertically Methods to integrate vertically aligned carbon nanotube thin films in interconnects and packaging

• Methods to fabricate densified vertically aligned carbon nanotube transparent conducting films

• Methods to fabricate densified vertically aligned carbon nanotube structures for thermal dissipation in packaging

Benefits

• Greatly improved mechanical, electrical and/or thermal properties of as-grown vertically aligned carbon nanotube thin films

• Maintains structure and anisotropic properties of as-grown vertically aligned carbon nanotube thin films

• Can be integrated into various microelectronic applications, simplifying fabrication processes

• Easy to scale up

• Greatly enhance electrical conductivity along both lateral and vertical directions of the film

• Can be integrated into solder ball, high-level contact and via through silicon

• Enhanced mechanical modulus, thermal conductivity, and electrical conductivity along the vertical directions of the films

Features

• Uses densified vertically aligned carbon nanotube thin film structure

• Develops a process to fabricate robust, reliable, and versatile carbon nanotube thin film sensors

• Develops a densification process to enhance various properties of vertically aligned carbon nanotube thin films, satisfying the requirements of applications in interconnects and packagingFabrication of Oriented Silicon Nano- Structures by e-Beam Lithography and Anisotropic Wet Etching

Background

Based on prior work for development of angstrom-scale measurement standards for the semiconductor industry, this innovation has made significant advancements in the alignment and control for etching lines/channels in silicon and silicon-on-insulator (SOI) structures. Prior alignment and etching methods were not precise enough to provide the necessary control. The resulting advancement allows production of nano-scale channels of very high quality, for example mechanical integrity, surface condition, and precise size and spacing. Additional capabilities include making columnar nano-structures.

Description

The key innovation is the ability to do electron beam lithography using an extremely precise and novel alignment method. With this alignment capability, it is possible to closely control etching along specific crystalline orientation to produce nano-channels of very small size, high dimensional accuracy, and quality

The nano-channel faces are extremely smooth, and the nano-structure walls are absent of crystalline defects that would otherwise arise with even the slightest misalignment of etching. Channels of the dimensions enabled by this innovation would otherwise have no mechanical integrity due to these crystalline defects. Various nano-channel and columnar structures have been produced to date. Capabilities also exist for producing such structures on SOI wafers.

Benefits

• Production of nano-channels and nano-columns of extremely high quality: high dimensional accuracy, surface smoothness, and mechanical robustness

• Nanometer level dimensional sizes and control

• Applicable to both silicon and SOI materials

• Amenable to low-cost production methods

Features

• Precise alignment of electron-beam lithography

• Broad potential across many different market applications

Applications

This is an enabling innovation with broad potential applications, including micro mirrors and optics, microelectronic interconnects, microelectronic devices (such as tri-gate or FIN/FET devices), environmental sensors, and various microfluidic and MEMS applications. Microfluidic and MEMS-related applications include drug delivery and sensors for study of cells, proteomics and genomics, and lab-on-a-chip type applications

Microfluidics is a rapidly developing field targeting the manipulation of miniature amounts of fluids, mainly for fast biochemical analysis. It deals with moving gaseous or liquid fluids in micro cavities and channels, and is at the crossroads of material sciences, surface science, microtechnology, fluid physics, and chemistry. Microfluidics has become of great interest due to its potential to speed up analytical throughput, integrate multiple tasks on a single platform, and decrease size and sample quantity, compared to established analytical tools.