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The micro-structural characterization of thermosonic cu-al intermetallic compounds and modelling of its interface stress

Thermosonic bonding of the Cu wire on Al bond pad is a common technology used in semiconductor industry. However, recent research show voids formation at this bonding interface on micro-chip, after an annealing treatment of High Temperature Storage (HTS). This voids formation is believed due to the...

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Main Author: Chua, Kok Yau
Format: Thesis
Language:English
English
Published: 2015
Subjects:
T Technology (General)
TS Manufactures
Online Access:http://eprints.utem.edu.my/id/eprint/16883/1/The%20Micro-Structural%20Characterization%20Of%20Thermosonic%20Cu-Al%20Intermetallic%20Compounds%20And%20Modelling%20Of%20Its%20Interface%20Stress.pdf
http://eprints.utem.edu.my/id/eprint/16883/2/The%20micro-structural%20characterization%20of%20thermosonic%20Cu-Al%20intermetallic%20compounds%20and%20modelling%20of%20its%20interface%20stress.pdf
http://eprints.utem.edu.my/id/eprint/16883/
https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=96181
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spelling my.utem.eprints.168832023-05-25T11:13:57Z http://eprints.utem.edu.my/id/eprint/16883/ The micro-structural characterization of thermosonic cu-al intermetallic compounds and modelling of its interface stress Chua, Kok Yau T Technology (General) TS Manufactures Thermosonic bonding of the Cu wire on Al bond pad is a common technology used in semiconductor industry. However, recent research show voids formation at this bonding interface on micro-chip, after an annealing treatment of High Temperature Storage (HTS). This voids formation is believed due to the volumetric changes of intermetallic compounds (IMCs) formed at the bonding interface. In previous research, effects of Cu free-air-ball and bonding temperature with high temperature storage (HTS) treatment on Cu-Al bonding interface are unclear. Besides, previous research provides inconclusive knowledge in the evolution of Cu-Al bonding interface due to inconsistent observations and variations in the bonding parameters. Research with statistical approach could be useful to address this limitation, however, it is yet to be established for Thermosonic Cu-Al interconnection. Besides, the void formation due to volumetric changes of IMC is discussed only qualitatively. A quantitative stress analysis could close the gap of research. Objectives of this research are (1) to analyse the correlation of wire bonding parameters, the interfacial micro-structure change and mechanical strength of the synthesized Cu-Al bonding interface, (2) to propose a theoretical model that describe quantitatively the stress due to volumetric changes originated from Cu-Al phase evolution, (3) to evaluate the stress generated by Cu-Al phase evolution at the bonding interface and its correlation to the void formation. Micro-structural characterizations were focused on crystallographic, compositional and mechanical analyses. It was found that bonding temperature resulted in an exponential increment for initial overall IMC thickness and average Cu content of the phases formed at the bonding interface. Moreover, HTS increase the overall IMC thickness by volume diffusion mechanism. The relationship between parameters, mechanical ball shear strength and IMC thickness were obtained statistically. A mathematical stress model based on assumptions of isotropic and elastic binary solid-solution was proposed. This model enabled an estimation of interfacial stresses from compositional measurements. It was found that the stress developed by interfacial Cu-Al IMC generally increased with the bonding temperature. Besides, forming gas supply was found to be less significant to affect the stress development, due to the oxide layers did not hinder much the interdiffusion of Cu and Al atoms. However, with HTS, the growth of Cu rich IMC increased the stress and caused gap within copper oxide layer. This work addressed the research gaps and offered a better understanding of the fundamental of Thermosonic Cu-Al interconnection. The results of the stress modelling could be a useful failure analysis technique for implementing Cu wire in the industry. 2015 Thesis NonPeerReviewed text en http://eprints.utem.edu.my/id/eprint/16883/1/The%20Micro-Structural%20Characterization%20Of%20Thermosonic%20Cu-Al%20Intermetallic%20Compounds%20And%20Modelling%20Of%20Its%20Interface%20Stress.pdf text en http://eprints.utem.edu.my/id/eprint/16883/2/The%20micro-structural%20characterization%20of%20thermosonic%20Cu-Al%20intermetallic%20compounds%20and%20modelling%20of%20its%20interface%20stress.pdf Chua, Kok Yau (2015) The micro-structural characterization of thermosonic cu-al intermetallic compounds and modelling of its interface stress. Doctoral thesis, Universiti Teknikal Malaysia Melaka. https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=96181
institution Universiti Teknikal Malaysia Melaka
building UTEM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Teknikal Malaysia Melaka
content_source UTEM Institutional Repository
url_provider http://eprints.utem.edu.my/
language English
English
topic T Technology (General)
TS Manufactures
spellingShingle T Technology (General)
TS Manufactures
Chua, Kok Yau
The micro-structural characterization of thermosonic cu-al intermetallic compounds and modelling of its interface stress
description Thermosonic bonding of the Cu wire on Al bond pad is a common technology used in semiconductor industry. However, recent research show voids formation at this bonding interface on micro-chip, after an annealing treatment of High Temperature Storage (HTS). This voids formation is believed due to the volumetric changes of intermetallic compounds (IMCs) formed at the bonding interface. In previous research, effects of Cu free-air-ball and bonding temperature with high temperature storage (HTS) treatment on Cu-Al bonding interface are unclear. Besides, previous research provides inconclusive knowledge in the evolution of Cu-Al bonding interface due to inconsistent observations and variations in the bonding parameters. Research with statistical approach could be useful to address this limitation, however, it is yet to be established for Thermosonic Cu-Al interconnection. Besides, the void formation due to volumetric changes of IMC is discussed only qualitatively. A quantitative stress analysis could close the gap of research. Objectives of this research are (1) to analyse the correlation of wire bonding parameters, the interfacial micro-structure change and mechanical strength of the synthesized Cu-Al bonding interface, (2) to propose a theoretical model that describe quantitatively the stress due to volumetric changes originated from Cu-Al phase evolution, (3) to evaluate the stress generated by Cu-Al phase evolution at the bonding interface and its correlation to the void formation. Micro-structural characterizations were focused on crystallographic, compositional and mechanical analyses. It was found that bonding temperature resulted in an exponential increment for initial overall IMC thickness and average Cu content of the phases formed at the bonding interface. Moreover, HTS increase the overall IMC thickness by volume diffusion mechanism. The relationship between parameters, mechanical ball shear strength and IMC thickness were obtained statistically. A mathematical stress model based on assumptions of isotropic and elastic binary solid-solution was proposed. This model enabled an estimation of interfacial stresses from compositional measurements. It was found that the stress developed by interfacial Cu-Al IMC generally increased with the bonding temperature. Besides, forming gas supply was found to be less significant to affect the stress development, due to the oxide layers did not hinder much the interdiffusion of Cu and Al atoms. However, with HTS, the growth of Cu rich IMC increased the stress and caused gap within copper oxide layer. This work addressed the research gaps and offered a better understanding of the fundamental of Thermosonic Cu-Al interconnection. The results of the stress modelling could be a useful failure analysis technique for implementing Cu wire in the industry.
format Thesis
author Chua, Kok Yau
author_facet Chua, Kok Yau
author_sort Chua, Kok Yau
title The micro-structural characterization of thermosonic cu-al intermetallic compounds and modelling of its interface stress
title_short The micro-structural characterization of thermosonic cu-al intermetallic compounds and modelling of its interface stress
title_full The micro-structural characterization of thermosonic cu-al intermetallic compounds and modelling of its interface stress
title_fullStr The micro-structural characterization of thermosonic cu-al intermetallic compounds and modelling of its interface stress
title_full_unstemmed The micro-structural characterization of thermosonic cu-al intermetallic compounds and modelling of its interface stress
title_sort micro-structural characterization of thermosonic cu-al intermetallic compounds and modelling of its interface stress
publishDate 2015
url http://eprints.utem.edu.my/id/eprint/16883/1/The%20Micro-Structural%20Characterization%20Of%20Thermosonic%20Cu-Al%20Intermetallic%20Compounds%20And%20Modelling%20Of%20Its%20Interface%20Stress.pdf
http://eprints.utem.edu.my/id/eprint/16883/2/The%20micro-structural%20characterization%20of%20thermosonic%20Cu-Al%20intermetallic%20compounds%20and%20modelling%20of%20its%20interface%20stress.pdf
http://eprints.utem.edu.my/id/eprint/16883/
https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=96181
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score 13.211869

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