Intermetallic phase transformations in Au-Al wire bonds

H. Xu; C. Liu; V. V. Silberschmidt; S. S. Pramana; T. J. White; Z. Chen; V. L. Acoff

doi:10.1016/j.intermet.2011.07.003

Intermetallic phase transformations in Au-Al wire bonds

H. Xu^*
, C. Liu
, V. V. Silberschmidt
, S. S. Pramana
, T. J. White
, Z. Chen
, V. L. Acoff

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

58 Citations (Scopus)

Abstract

This paper describes the crystallochemical mechanisms that underpin the migration of nano-size alumina, intermetallic growth and phase transformations in Au-Al wire bonds during annealing from 175 °C to 250 °C by utilizing high-resolution transmission electron microscopy (HRTEM). Alumina, encapsulated within the Au-Al intermetallic compounds (IMCs), migrates towards the Au ball during annealing, with Au diffusion into the Al pad. The sequence of Au-Al IMC phase development during annealing was investigated. Initially, Au ₈Al₃ appears as a third phase between the Au₄Al and AuAl₂ layers that form during bonding, and gradually becomes the dominant compound. Both AuAl₂ and Au₈Al₃ are transformed into the Au-rich alloyAu₄Al when Al is completely consumed, and this is the terminal product.

Original language	English
Pages (from-to)	1808-1816
Number of pages	9
Journal	Intermetallics
Volume	19
Issue number	12
DOIs	https://doi.org/10.1016/j.intermet.2011.07.003
Publication status	Published - Dec 2011

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title = "Intermetallic phase transformations in Au-Al wire bonds",

abstract = "This paper describes the crystallochemical mechanisms that underpin the migration of nano-size alumina, intermetallic growth and phase transformations in Au-Al wire bonds during annealing from 175 °C to 250 °C by utilizing high-resolution transmission electron microscopy (HRTEM). Alumina, encapsulated within the Au-Al intermetallic compounds (IMCs), migrates towards the Au ball during annealing, with Au diffusion into the Al pad. The sequence of Au-Al IMC phase development during annealing was investigated. Initially, Au 8Al3 appears as a third phase between the Au4Al and AuAl2 layers that form during bonding, and gradually becomes the dominant compound. Both AuAl2 and Au8Al3 are transformed into the Au-rich alloyAu4Al when Al is completely consumed, and this is the terminal product.",

keywords = "A. Aluminides, B. Phase transformation, C. Wire bonding, D. Microstructure, F. Electron microscopy",

author = "H. Xu and C. Liu and Silberschmidt, \{V. V.\} and Pramana, \{S. S.\} and White, \{T. J.\} and Z. Chen and Acoff, \{V. L.\}",

year = "2011",

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doi = "10.1016/j.intermet.2011.07.003",

language = "English",

volume = "19",

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journal = "Intermetallics",

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TY - JOUR

T1 - Intermetallic phase transformations in Au-Al wire bonds

AU - Xu, H.

AU - Liu, C.

AU - Silberschmidt, V. V.

AU - Pramana, S. S.

AU - White, T. J.

AU - Chen, Z.

AU - Acoff, V. L.

PY - 2011/12

Y1 - 2011/12

N2 - This paper describes the crystallochemical mechanisms that underpin the migration of nano-size alumina, intermetallic growth and phase transformations in Au-Al wire bonds during annealing from 175 °C to 250 °C by utilizing high-resolution transmission electron microscopy (HRTEM). Alumina, encapsulated within the Au-Al intermetallic compounds (IMCs), migrates towards the Au ball during annealing, with Au diffusion into the Al pad. The sequence of Au-Al IMC phase development during annealing was investigated. Initially, Au 8Al3 appears as a third phase between the Au4Al and AuAl2 layers that form during bonding, and gradually becomes the dominant compound. Both AuAl2 and Au8Al3 are transformed into the Au-rich alloyAu4Al when Al is completely consumed, and this is the terminal product.

AB - This paper describes the crystallochemical mechanisms that underpin the migration of nano-size alumina, intermetallic growth and phase transformations in Au-Al wire bonds during annealing from 175 °C to 250 °C by utilizing high-resolution transmission electron microscopy (HRTEM). Alumina, encapsulated within the Au-Al intermetallic compounds (IMCs), migrates towards the Au ball during annealing, with Au diffusion into the Al pad. The sequence of Au-Al IMC phase development during annealing was investigated. Initially, Au 8Al3 appears as a third phase between the Au4Al and AuAl2 layers that form during bonding, and gradually becomes the dominant compound. Both AuAl2 and Au8Al3 are transformed into the Au-rich alloyAu4Al when Al is completely consumed, and this is the terminal product.

KW - A. Aluminides

KW - B. Phase transformation

KW - C. Wire bonding

KW - D. Microstructure

KW - F. Electron microscopy

UR - https://www.scopus.com/pages/publications/80052033776

U2 - 10.1016/j.intermet.2011.07.003

DO - 10.1016/j.intermet.2011.07.003

M3 - Article

SN - 0966-9795

VL - 19

SP - 1808

EP - 1816

JO - Intermetallics

JF - Intermetallics

IS - 12

ER -

Intermetallic phase transformations in Au-Al wire bonds

Abstract

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