Chapter 6 Micro/Nanolithography Using Self-Assembled Monolayers (SAMs)

Abstract

Publisher Summary This chapter focuses on the definition, preparation methods, usefulness, and various applications of self-assembled monolayer (SAM). Self-assembled monolayer is a single layer of organic molecules formed on a substrate in a liquid or gas phase. When a suitable combination of a substrate material and organic molecules is selected and the substrate is located into a solution or vapor, which contains the organic molecules, the molecules are chemically adsorbed onto the substrate surface through the chemical reaction of the molecules with the substrate material. The thicknesses of SAMs are 1–2 nm, depending on the length of molecules comprising the monolayer. Moreover, the SAMs consist of molecules of the same kind, and there is no variation in molecular mass in SAMs, which is in contrast to the polymer films. Therefore, SAMs are highly promising as high-resolution resists. The uniform coating of SAMs is also possible onto substrates with three-dimensional complex shapes, fine-structured substrates, and inner surfaces of tubes. From the viewpoint of environmental issues, conventional lithographic processes discharge liquid wastes, such as developing solutions and resist removal ones; however, the SAM lithographic process does not discharge liquid waste. The consumption of raw materials used in the process is extremely small because of the thickness of 1–2 nm.