(Keynote) Mechanisms of ALD: Toward Applications in Area Selective Deposition

Abstract

With the growing demands on nanostructure fabrication for advanced electronics, area selective deposition is gaining attention as an important process to achieve pattern features at the sub-10 nm length scale. Area selective deposition is a bottom-up patterning process in which material is deposited only where desired. This talk will describe how control over the substrate surface properties can be used to achieve area selective atomic layer deposition (AS-ALD). The technique of ALD relies on self-saturating, layer-by-layer, gas-surface reactions to deposit conformal thin film materials and is a good choice for selective deposition because its chemical specificity provides a means to achieve selectivity on a spatially patterned substrate. A deep understanding of the gas-surface chemistry behind ALD can be critical toward developing area selective processes. First, research into the fundamental chemical mechanisms of ALD will be illustrated. Then, the development of inhibitory layers such as self-assembled monolayers (SAMs) to alter the native surface reactivity will be described. We will show that this process provides good selectivity in the deposition of thin films on a variety of substrate materials, including dielectrics and metals such as Cu, Co, W and Ru. The talk will conclude with a discussion of the prospects of area selective deposition for future materials fabrication.