Electrochemical Atomic Layer Deposition of Metals for Applications in Semiconductor Interconnect Metallization

Bibliographic Details
Main Author:	Venkatraman, Kailash
Language:	English
Published:	Case Western Reserve University School of Graduate Studies / OhioLINK 2019
Subjects:	Nanotechnology Chemical Engineering underpotential deposition surface-limited redox replacement electrochemical atomic layer deposition diffusion-reaction modeling electroless underpotential deposition electroless atomic layer deposition
Online Access:	http://rave.ohiolink.edu/etdc/view?acc_num=case1543839404490434

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spelling	ndltd-OhioLink-oai-etd.ohiolink.edu-case15438394044904342021-08-03T07:09:05Z Electrochemical Atomic Layer Deposition of Metals for Applications in Semiconductor Interconnect Metallization Venkatraman, Kailash Nanotechnology Chemical Engineering underpotential deposition surface-limited redox replacement electrochemical atomic layer deposition diffusion-reaction modeling electroless underpotential deposition electroless atomic layer deposition High-performance microprocessors and memory devices require miniaturized copper (Cu) interconnects that carry electrical signals to circuit elements such as transistors. Conventionally, these nanoscale Cu interconnects are fabricated using electrodeposition; however, with the continued scaling of the interconnects below 10 nm, electrodeposition does not allow the requisite atomic-scale control over the interconnect fabrication process. As a result, future interconnect fabrication will require novel materials fabrication techniques. Vapor-phase atomic layer deposition (ALD) is a promising alternative to replace the conventional electrodeposition approach; however, a major drawback of the vapor-phase Cu ALD process is that it uses metalorganic precursors which are highly unstable, undergo decomposition and thus introduce contaminants in the metal deposit. To address such critical issues, we pursue here the development of an electrochemical atomic layer deposition (e-ALD) process which utilizes benign liquid-phase precursors in combination with electrode potential manipulation for the deposition of atomic-scale metal films. In the present work, a novel electrochemical atomic layer deposition process for copper (Cu) and cobalt (Co) is developed. The process is mediated by zinc underpotential deposition (Znupd) which serves as a sacrificial adlayer. Zn underpotential deposition is studied using cyclic voltammetry and quartz crystal microbalance. Chronoamperometry studies on a rotating disk electrode provide insights into the diffusion-reaction properties of the Znupd process. A general strategy for e-ALD is developed which involves deposition of a sacrificial monolayer of Zn via underpotential deposition followed by its spontaneous redox replacement (SLRR) by the desired noble metal (Cu or Co). UPD+SLRR cycles are repeated to build multi-layered metal deposits with controlled thickness in the sub-nm range and minimal surface roughness amplification. Layer-by-layer growth mode of Cu e-ALD is experimentally confirmed using quartz crystal microgravimetry and anodic stripping coulometry. Through considerations of the unsteady-state diffusional transport of species and the time-dependent surface redox reactions, a semi-analytical e-ALD process model is developed. The developed model provides quantitative information about the e-ALD growth rate and the deposit surface roughness as a function of various e-ALD process parameters, i.e., electrolyte composition and deposition time. Model predictions are compared to experimental measurements of the growth rate and deposit roughness. Furthermore, electroless Cu e-ALD process is developed in which the sacrificial Znupd step can be facilitated without applying an external potential to the substrate. This allows e-ALD to be used when the substrate is highly-resistive or contains electrically-isolated micro-patterned features. 2019-02-01 English text Case Western Reserve University School of Graduate Studies / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=case1543839404490434 http://rave.ohiolink.edu/etdc/view?acc_num=case1543839404490434 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection	NDLTD
language	English
sources	NDLTD
topic	Nanotechnology Chemical Engineering underpotential deposition surface-limited redox replacement electrochemical atomic layer deposition diffusion-reaction modeling electroless underpotential deposition electroless atomic layer deposition
spellingShingle	Nanotechnology Chemical Engineering underpotential deposition surface-limited redox replacement electrochemical atomic layer deposition diffusion-reaction modeling electroless underpotential deposition electroless atomic layer deposition Venkatraman, Kailash Electrochemical Atomic Layer Deposition of Metals for Applications in Semiconductor Interconnect Metallization
author	Venkatraman, Kailash
author_facet	Venkatraman, Kailash
author_sort	Venkatraman, Kailash
title	Electrochemical Atomic Layer Deposition of Metals for Applications in Semiconductor Interconnect Metallization
title_short	Electrochemical Atomic Layer Deposition of Metals for Applications in Semiconductor Interconnect Metallization
title_full	Electrochemical Atomic Layer Deposition of Metals for Applications in Semiconductor Interconnect Metallization
title_fullStr	Electrochemical Atomic Layer Deposition of Metals for Applications in Semiconductor Interconnect Metallization
title_full_unstemmed	Electrochemical Atomic Layer Deposition of Metals for Applications in Semiconductor Interconnect Metallization
title_sort	electrochemical atomic layer deposition of metals for applications in semiconductor interconnect metallization
publisher	Case Western Reserve University School of Graduate Studies / OhioLINK
publishDate	2019
url	http://rave.ohiolink.edu/etdc/view?acc_num=case1543839404490434
work_keys_str_mv	AT venkatramankailash electrochemicalatomiclayerdepositionofmetalsforapplicationsinsemiconductorinterconnectmetallization
_version_	1719454738960875520

Electrochemical Atomic Layer Deposition of Metals for Applications in Semiconductor Interconnect Metallization

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