The Role of Ultrafine Crystalline Behavior and Trace Impurities in Copper on Intermetallic Void Formation

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The Role of Ultrafine Crystalline Behavior and Trace Impurities in Copper on Intermetallic Void Formation. / Ross, Glenn; Malmberg, Per; Vuorinen, Vesa; Paulasto-Kröckel, Mervi.

In: ACS Applied Electronic Materials, Vol. 1, No. 1, 2019, p. 88-95.

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@article{a084809558534ec89871898dce891c61,
title = "The Role of Ultrafine Crystalline Behavior and Trace Impurities in Copper on Intermetallic Void Formation",
abstract = "In the microelectronic component industry, because of the miniaturization of functional units, the interaction of materials and interfaces play a much more significant role in their performance. The result of this is that ultrafine crystalline and trace impurity behavior impact a device’s operation to a much greater extent. This is the case with micro-connects for 3D integration, such as micro-bumps. Any unwanted crystalline behavior or interfacial segregated impurities can drastically alter a micro-connect’s performance, with a particular issue being intermetallic void formation, often known as Kirkendall voiding. Currently, it is unclear under what conditions voids form and how to prevent them. This work studies the microstructural and compositional differences between samples with different voiding densities. Results show that samples that exhibit an ultrafine crystalline have a higher propensity to exhibit voiding. Also, there is a high concentration of trace impurities located in the electrochemically deposited Cu layer. After isothermal annealing, high concentrations of impurities are located at the interface between Cu and the Cu–Sn intermetallic compound of Cu3Sn. An alternative explanation to the traditional Kirkendall void formation theory is presented. The explanation is based on the interaction of trace impurities from the electroplating process and the microstructural evolution.",
keywords = "intermetallic voids, Kirkendall voids, microstructure, impurities, residual stress, scanning, transmission electron microscopy, X-ray diffraction, time-of-flight secondary ion mass spectroscopy",
author = "Glenn Ross and Per Malmberg and Vesa Vuorinen and Mervi Paulasto-Kr{\"o}ckel",
year = "2019",
doi = "10.1021/acsaelm.8b00029",
language = "English",
volume = "1",
pages = "88--95",
journal = "ACS Applied Electronic Materials",
issn = "2637-6113",
publisher = "AMERICAN CHEMICAL SOCIETY",
number = "1",

}

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TY - JOUR

T1 - The Role of Ultrafine Crystalline Behavior and Trace Impurities in Copper on Intermetallic Void Formation

AU - Ross, Glenn

AU - Malmberg, Per

AU - Vuorinen, Vesa

AU - Paulasto-Kröckel, Mervi

PY - 2019

Y1 - 2019

N2 - In the microelectronic component industry, because of the miniaturization of functional units, the interaction of materials and interfaces play a much more significant role in their performance. The result of this is that ultrafine crystalline and trace impurity behavior impact a device’s operation to a much greater extent. This is the case with micro-connects for 3D integration, such as micro-bumps. Any unwanted crystalline behavior or interfacial segregated impurities can drastically alter a micro-connect’s performance, with a particular issue being intermetallic void formation, often known as Kirkendall voiding. Currently, it is unclear under what conditions voids form and how to prevent them. This work studies the microstructural and compositional differences between samples with different voiding densities. Results show that samples that exhibit an ultrafine crystalline have a higher propensity to exhibit voiding. Also, there is a high concentration of trace impurities located in the electrochemically deposited Cu layer. After isothermal annealing, high concentrations of impurities are located at the interface between Cu and the Cu–Sn intermetallic compound of Cu3Sn. An alternative explanation to the traditional Kirkendall void formation theory is presented. The explanation is based on the interaction of trace impurities from the electroplating process and the microstructural evolution.

AB - In the microelectronic component industry, because of the miniaturization of functional units, the interaction of materials and interfaces play a much more significant role in their performance. The result of this is that ultrafine crystalline and trace impurity behavior impact a device’s operation to a much greater extent. This is the case with micro-connects for 3D integration, such as micro-bumps. Any unwanted crystalline behavior or interfacial segregated impurities can drastically alter a micro-connect’s performance, with a particular issue being intermetallic void formation, often known as Kirkendall voiding. Currently, it is unclear under what conditions voids form and how to prevent them. This work studies the microstructural and compositional differences between samples with different voiding densities. Results show that samples that exhibit an ultrafine crystalline have a higher propensity to exhibit voiding. Also, there is a high concentration of trace impurities located in the electrochemically deposited Cu layer. After isothermal annealing, high concentrations of impurities are located at the interface between Cu and the Cu–Sn intermetallic compound of Cu3Sn. An alternative explanation to the traditional Kirkendall void formation theory is presented. The explanation is based on the interaction of trace impurities from the electroplating process and the microstructural evolution.

KW - intermetallic voids

KW - Kirkendall voids

KW - microstructure

KW - impurities

KW - residual stress

KW - scanning

KW - transmission electron microscopy

KW - X-ray diffraction

KW - time-of-flight secondary ion mass spectroscopy

U2 - 10.1021/acsaelm.8b00029

DO - 10.1021/acsaelm.8b00029

M3 - Article

VL - 1

SP - 88

EP - 95

JO - ACS Applied Electronic Materials

JF - ACS Applied Electronic Materials

SN - 2637-6113

IS - 1

ER -

ID: 30465477