To read this content please select one of the options below:

Microstructure evolution of Au/SnSb-CuNiAg/(Au)Ni during high temperature aging

Bangyao Han (School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin, China)
Fenglian Sun (School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin, China)
Tianhui Li (School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin, China)
Yang Liu (School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin, China)

Soldering & Surface Mount Technology

ISSN: 0954-0911

Article publication date: 3 October 2019

Issue publication date: 18 March 2020

92

Abstract

Purpose

The purpose of this paper is to investigate the morphology evolution and the composition transformation of Au-Sn intermetallic compounds (IMCs) of the new Au/Sn-5Sb-1Cu-0.1Ni-0.1Ag/(Au)Ni solder joint during the high temperature aging.

Design/methodology/approach

Sn-5Sb-1Cu-0.1Ni-0.1Ag solder balls (500 µm in diameter), heat sink with structure of 7.4 µm Au layer on 5 µm Ni-plated Cu alloy and Si chip with 5.16 µm plated Au were used to fabricate micro-solder joints. The joints were performed in a furnace at 150°C for 150, 250 and 350 h aging. The samples were polished and deep etched before analyzed by metallographic microscope and scanning electron microscopy, respectively. Energy dispersive x-ray spectroscopy was used to identify the composition of the IMCs.

Findings

ß-(Au,Ni,Cu)10Sn phase is formed during the soldering process. The IMCs evolution has two periods during the aging. The first is the ξ-(Au,Ni,Cu)5Sn, ξ-(Au,Cu)5Sn and δ-AuSn were formed and grew to form a full-compound joint after about 150 h aging. The second is the conversion of the full-compound joint. The IMCs converted to ξ′ phase when the aging time extends to 250 h, and transformed to ε-(Au,Ni,Cu)Sn2 and η-(Au,Ni,Cu)Sn4 after 350 h aging. The thicker gold layer and thinner solder joint can promote the growth of the IMCs. ß-(Au,Ni,Cu)10Sn emerged in Au/SnSb-CuNiAg/(Au)Ni in this research, which is not usually found.

Originality/value

The results in this study have a significant meaning for the application of the new Sn-5Sb-1Cu-0.1Ni-0.1Ag in harsh conditions.

Keywords

Citation

Han, B., Sun, F., Li, T. and Liu, Y. (2020), "Microstructure evolution of Au/SnSb-CuNiAg/(Au)Ni during high temperature aging", Soldering & Surface Mount Technology, Vol. 32 No. 2, pp. 57-64. https://doi.org/10.1108/SSMT-04-2019-0015

Publisher

:

Emerald Publishing Limited

Copyright © 2019, Emerald Publishing Limited

Related articles