NDLI: Effects of fine size lead-free solder ball on the interfacial reactions and joint reliability

Content Provider	IEEE Xplore Digital Library
Author	Yong-Sung Park Yong-Min Kwon Jeong-Tak Moon Young-Woo Lee Jae-Hong Lee Kyung-Wook Paik
Copyright Year	2009
Description	Author affiliation: MK ELECTRON CO., LTD 316-2, Kumeu-ri, Pogok-myun, Yongin-si, Gyeonggi-do, Korea (Jeong-Tak Moon; Young-Woo Lee; Jae-Hong Lee) \|\| Dept. of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST) 373-1, Guseong-dong, Yuseong-gu, Daejeon, 305-701, Korea (Yong-Sung Park; Yong-Min Kwon; Kyung-Wook Paik)
Abstract	To satisfy the requirements of the newest mobile product, smaller solder ball is needed for electronic packages such as chip scale package (CSP). The purpose of this study was to investigate the effect of solder ball size on the interfacial reaction. In this study, 400, 300, and, 200 μm diameter solder balls of 98.5 wt.% Sn, 1 wt.% Ag, and 0.5 wt.% Cu(SAC105) were formed on the Cu/OSP and electroplated Ni/Au pads at 250°C. In the case of the reaction with Cu/OSP, as solder ball size decreased, the thickness of Cu6Sn5 intermetallic compounds (IMCs) increased and Cu concentrations of solder balls increased. In the case of fine solder ball, Cu dissolution rate into molten solder was faster than large solder ball due to its high pad area/solder volume ratio (A/V ratio). Fast Cu dissolution into molten solder promoted the IMC growth. In the case of the reaction with electroplated Ni/Au, (Cu,Ni)6Sn5 IMCs were only formed in the interface of 400 μm solder ball. Both (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4 IMCs were formed at the interface of 300 μm solder ball. (Ni,Cu)3Sn4 IMCs were only formed at the interface of 200 μm solder ball. The absolute Cu contents of 200 μm solder ball was smaller than 300 and 400 μm solder ball due to its smaller volume. (Ni,Cu)3Sn4 IMCs were formed by the insufficient Cu contents in 200 μm solder ball. The substrate design with smaller A/V ratio and the SAC alloy with higher Cu contents (>0.5 wt.%) were recommended to reduce the IMC growth.
Starting Page	321
Ending Page	324
File Size	2030175
Page Count	4
File Format	PDF
ISBN	9781424450992
e-ISBN	9781424451005
DOI	10.1109/EPTC.2009.5416528
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2009-12-09
Publisher Place	Singapore
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Environmentally friendly manufacturing techniques Lead Gold Soldering Chip scale packaging Electronics packaging Materials science and technology Integrated circuit interconnections Scanning electron microscopy Materials reliability
Content Type	Text
Resource Type	Article

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