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Indexed by:期刊论文

Date of Publication:2009-01-01

Journal:SOLDERING & SURFACE MOUNT TECHNOLOGY

Included Journals:SCIE、EI、CPCI-S、Scopus

Volume:21

Issue:2

Page Number:19-23

ISSN No.:0954-0911

Key Words:Solders; Soldering; Chemical reactions

Abstract:Purpose - The paper aims to investigate the interfacial reactions between two Sn-Cu based multicomponent Pb-free solders, Sn-2Cu-0.5Ni and Sn2Cu-0.5Ni-0.5Au (wt per cent), and Ni substrates during soldering and aging.
   Design/methodology/approach - Differential scanning calorimetry (DSC) was performed to measure the melting behaviors of the solders and determine the temperature of soldering. DSC tests showed that the onset temperature were 227.47 and 224.787 degrees C for Sn-2Cu-0.5Ni and Sn-2Cu-0.5Ni0.5Au, respectively. Two intermetallic compounds (IMCs), Cu(6)Sn(5) and (Cu,Ni)(6)Sn(5), were formed in Sn-2Cu-0.5Ni solder. While the IMCs detected in Sn-2Cu-0.5Ni-0.5Au matrix were (Cu,Ni)(6)Sn(5), (Cu,Au)(6)Sn(5) and (Cu,Ni)(6)Sn(5). The IMC layer formed at the both solder/Ni interfaces was (Cu,Ni)(6)Sn(5) with stick-lick morphology after soldering at 260 degrees C.
   Findings - The interfacial IMC layers became planar when aged at 170 degrees C for 500 h. However, cracks were found in the IMC layers at both joints when the aging time reached 1,000 h, that implies reliability problem may exist in the joints. Moreover, Au-containing IMCs were found on the top of the IMC layer in Sn-2Cu-0.5Ni-0.5Au/Ni joint after for 1,000 h.
   Originality/value - This study focuses on the interfacial reactions of Sn-2Cu-0.5Ni/Ni and Sn-2Cu-0.5Au/Ni during soldering and isothermal aging.