Pick-and-place nanoassembly

Abstract

A new all-additive method for direct fabrication of nanometer-scale planar and multilayer structures using the probe tip of an atomic force microscope (AFM) and a material reservoir is proposed. The process, which is called Pick-and-Place NanoAssembly, enables true "pick-and-place" retrieval and deposition of materials with a wide range of electrical, chemical, and mechanical properties. The silicon tip of an AFM is used to discretely pick up molecules from a reservoir, transfer them to a construction zone, and then weld them to a surface. Unlike the prior art, this assembly method offers high-resolution direct patterning of a variety of materials, many of which are not amenable to patterning using current probe-based or conventional lithography methods. Metal nanoparticles, polymers, inks, solvents, and organics have been deposited onto a variety of substrates with resolutions approaching 1 million dots per inch (1 trillion dots per square inch). Lines of nanoparticles have been deposited with line widths of less than 17 nm. These materials can be assembled using reservoirs of viscous liquids, non-viscous liquids, and soft solids. Deposited volumes span a range of 10 orders of magnitude from 10-24 to 10-14 liters. Structures with dimensions of 60 to 100 nm are common.

he patterning process is capable of creating structures with height-to-width aspect ratios of better than 1-to-2, and is relatively insensitive to fluctuations in temperature (3 - 30 C) and humidity (0% - 90%). Methods for the fabrication of multi-layer structures and routes towards true three-dimensional structures are also introduced. It is anticipated that Pick-and-Place NanoAssembly will be suitable for precision deposition and direct patterning of a wide range of useful materials including semiconductors and biological compounds such as DNA. This technique promises to be an enabling tool for biological, chemical, and molecular electronics applications throughout the field of nanotechnology. Near-term applications may include the fabrication of ultra-high density gene chips, high-capacity nano-patterned magnetic disk drives, and single electron transistors.