Employment of a bi-layer of Ni(P)/Cu as a diffusion barrier in a Cu/Sn/Cu bonding structure for three-dimensional interconnects

This study explored the possibility of employing a bi-layer barrier of electroless-plated Ni(P)/thin Cu layers in a Cu/Sn/Cu bonding structure for three-dimensional interconnects. Our materials analysis revealed that the bi-layer barrier served effectively as a diffusion barrier and prevented full-s...

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Bibliographic Details
Main Authors: Lee, Byunghoon, Jeon, Haseok, Kwon, Kee-Won, Lee, Hoo-Jeong
Other Authors: School of Materials Science & Engineering
Format: Article
Language:English
Published: 2013
Subjects:
Online Access:https://hdl.handle.net/10356/101556
http://hdl.handle.net/10220/16535
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Institution: Nanyang Technological University
Language: English
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Summary:This study explored the possibility of employing a bi-layer barrier of electroless-plated Ni(P)/thin Cu layers in a Cu/Sn/Cu bonding structure for three-dimensional interconnects. Our materials analysis revealed that the bi-layer barrier served effectively as a diffusion barrier and prevented full-scale materials interaction for temperatures higher than 300 °C. Such suppression of an intermetallic compound reaction and limiting Cu diffusion led to the formation of a rod-shaped Cu6Sn5 compound, rendering a unique microstructure of ductile Sn embedded with strong Cu6Sn5 rods. Our mechanical characterization using lap-shear testing and fracture analysis revealed that the sample with such a microstructure displayed a high bonding strength with some ductility, a desirable combination for high mechanical reliability.