Suppression of Kirkendall voiding in Sn-3.5Ag/Cu solder joints by pre-annealing process

2011 ◽  
Vol 2011 (1) ◽  
pp. 000337-000340
Author(s):  
S. H. Kim ◽  
Jin Yu
Keyword(s):  
Solder Joints ◽  
Void Formation ◽  
Annealing Process ◽  
Schematic Diagram ◽  
Cu Films ◽  
Joint Reliability ◽  
Organic Impurities ◽  
Solder Reflow ◽  
Kirkendall Voids ◽  
Annealing Method

In this study, electroplated Cu films were pre-annealed at T (T = 673, 773, 873 K) for varying times. Sn-3.5Ag solder reflowed over the Cu films and subsequently aged at 150°C for 240 hrs. Effects of pre-annealing on the microstructure of Cu films, as well as contents of organic impurities incorporated in the Cu films were investigated. After solder reflow, the formation of Kirkendall voids at Cu3Sn/Cu interface was observed from SEM micrographs. Results show that the pre-annealing process significantly suppressed Kirkendall void formation in the Sn-3.5Ag/Cu solder joints. A line fraction of voids at the Cu3Sn/Cu interface was definitely suppressed in the case of 500°C and 600°C pre-annealed samples compared to as-deposited Cu sample. SIMS analyses revealed that pre-annealing reduced the level of impurities in the Cu films, especially S and C. The mechanism of suppressing Kirkendall voids at the Cu3Sn/Cu interface was presented by schematic diagram, and it could be seen that pre-annealing method has a potential to enhance solder joint reliability.

Effects of Fe on the Kirkendall Void Formation of Sn-3.5Ag-xFe/Cu Solder Joints

2010 ◽  
Vol 2010 (1) ◽  
pp. 000294-000297 ◽  
Author(s):  
S. H. Kim ◽  
Jin Yu
Keyword(s):  
Solder Joint ◽  
Solder Joints ◽  
Void Formation ◽  
Kirkendall Void ◽  
Fe Content ◽  
Kirkendall Voids

Ternary Sn-3.5Ag-xFe solders with varying amount of Fe; 0.1, 0.5, 1.0, and 2.0 wt. % were reacted with Cu UBM which was electroplated using SPS additive and characteristics of Kirkendall void formation at the solder joints were investigated. Results indicate that the propensity to form Kirkendall voids at the solder joint decreased with the Fe content. It showed that Fe dissolved in the Cu UBM and reduced the segregation of S atoms to the Cu3Sn/Cu interface, which suppressed the nucleation of Kirkendall voids at the interface.

Kirkendall void formation in eutectic SnPb solder joints on bare Cu and its effect on joint reliability

2005 ◽  
Vol 97 (2) ◽  
pp. 024508 ◽  
Author(s):  
Kejun Zeng ◽  
Roger Stierman ◽  
Tz-Cheng Chiu ◽  
Darvin Edwards ◽  
Kazuaki Ano ◽  
...  
Keyword(s):  
Solder Joints ◽  
Void Formation ◽  
Kirkendall Void ◽  
Joint Reliability ◽  
Snpb Solder ◽  
Eutectic Snpb

scholarly journals Effects of Impurity on Void Formation at Interface between Sn-3.0Ag-0.5Cu and Cu Electroplated Film

2021 ◽  
Author(s):  
Ping-Chen Chiang ◽  
Yu-An Shen ◽  
Chih-Ming Chen
Keyword(s):  
Solder Joint ◽  
Thermal Aging ◽  
Solder Joints ◽  
Void Formation ◽  
Interfacial Structure ◽  
Joint Interface ◽  
Grain Texture ◽  
Cu Films ◽  
Impurity Control ◽  
Electroplating Process

Abstract Void formation is a critical reliability concern for solder joints in electronic packaging. The control of microstructures and impurity quantities in Cu electroplated films significantly affects the void formation at the joint interface, but the studies for their comparison are seldom. In this study, three Cu films (termed as A, B, and C) are fabricated using an electroplating process. The Cu A film has a facted grain texture embedded with twins while Cu B and C have a similar columnar texture. After thermal aging at 200°C for 1000 h, the SAC 305 (Sn-3.0Ag-0.5Cu) solder joints with Cu A and B exhibit a robust interfacial structure without voids. However, microstructural collapse is observed in the solder joint of SAC 305/Cu C, where many crevives parallel to the interface are formed. Based on the microanalysis, the concentration of impurity is higher in the Cu C film than those in Cu A and B. Moreover, discrete voids rather than continuous crevices are presented in the SAC305/Cu C system when the impurity concentration in Cu C is reduced. The findings demonstrate that the impurity control in the Cu electroplated film is critical for the control of void/crevice formation in the electronic solder joints.

scholarly journals Improvement in Thermomechanical Reliability of Low Cost Sn-Based BGA Interconnects by Cr Addition

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 586 ◽  
Author(s):  
Junghwan Bang ◽  
Dong-Yurl Yu ◽  
Ming Yang ◽  
Yong-Ho Ko ◽  
Jeong-Won Yoon ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Solder Joints ◽  
Low Cost ◽  
Thermal Shock Test ◽  
Shock Condition ◽  
Joint Reliability ◽  
Cu3sn Layer ◽  
Kirkendall Voids ◽  
Free Solder ◽  
Thermomechanical Reliability

The exemption of Pb-bearing automobile electronics in the End of Life Vehicle (ELV) directive has recently expired, bring an urgent need to find Pb-free alloys that can maintain good performance under high-temperature and vibration conditions for automobile application. In this study, a new lead-free solder, Sn-0.7Cu-0.2Cr (wt.%) alloy, was developed. To evaluate the thermomechanical reliability of the new solder alloy in automobile electronics, a thermal shock test was performed. The results show that the presence of Cr in solder inhibits the growth of interfacial Cu3Sn layer and the formation of Kirkendall voids, which effectively improves the joint reliability under intense thermal shock condition compared with the commercial SAC305 and SC07 solders. Specifically, the shear strength of the Sn-0.7Cu-0.2Cr/Cu solder joints was higher by 23% and 44% than that of SAC305 and SC07 solder joints after 2000 cycles of thermal shock at 1 m/s shear speed.

Interfacial reactions and impact reliability of Sn–Zn solder joints on Cu or electroless Au/Ni(P) bond-pads

2004 ◽  
Vol 19 (10) ◽  
pp. 2887-2896 ◽  
Author(s):  
M. Date ◽  
K.N. Tu ◽  
T. Shoji ◽  
M. Fujiyoshi ◽  
K. Sato
Keyword(s):  
Impact Toughness ◽  
Solder Joints ◽  
Void Formation ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Joint Reliability ◽  
Solder Balls ◽  
Bond Interface ◽  
Impact Reliability ◽  
The Impact

Sn–9Zn and Sn–8Zn–3Bi solder balls were bonded to Cu or electroless Au/Ni(P)pads, and the effect of aging on joint reliability, including impact reliability, was investigated. For the purpose of quantitatively evaluating the impact toughness ofthe solder joints, a test similar to the classic Charpy impact test was performed.The interfacial compounds formed in the solder/Cu joint during soldering wereCu–Zn intermetallic compounds (IMCs), not Cu–Sn IMCs. One of the Cu–Zn IMCs, γ–Cu5Zn8, thickened remarkably with aging, and eventually its morphology changed from layer-type into discontinuous. The rapid growth of the γ–Cu5Zn8 and void formation at the bond interface led to the significant degradation of the joint reliability due to a ductile-to-brittle transition of the joint. Meanwhile, the compound formed in the solder/Au/Ni(P) joint during soldering was a Au–Zn IMC, above which Zn redeposited during aging. Both the dissolution and diffusion of Ni into the solders were extremely slow, which contributes to negligible void formation at the bond interface. As a result, the solder bumps on the Au/Ni(P) pads were able to maintain the high joint strength and impact toughness even after prolonged aging.

Void Formation and Their Effect on Reliability of Lead-Free Solder Joints on MID and PCB Substrates

2017 ◽  
Vol 66 (4) ◽  
pp. 1229-1237 ◽  
Author(s):  
P. Wild ◽  
T. Grozinger ◽  
D. Lorenz ◽  
A. Zimmermann
Keyword(s):  
Solder Joints ◽  
Void Formation ◽  
Lead Free ◽  
Lead Free Solder ◽  
Free Solder

Quantitative Evaluation of Voids in Lead Free Solder Joints

2015 ◽  
Vol 772 ◽  
pp. 284-289 ◽  
Author(s):  
Sabuj Mallik ◽  
Jude Njoku ◽  
Gabriel Takyi
Keyword(s):  
Solder Bump ◽  
Solder Joints ◽  
Void Formation ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Paste ◽  
X Ray ◽  
Size And Shape ◽  
Solder Bumps ◽  
Free Solder

Voiding in solder joints poses a serious reliability concern for electronic products. The aim of this research was to quantify the void formation in lead-free solder joints through X-ray inspections. Experiments were designed to investigate how void formation is affected by solder bump size and shape, differences in reflow time and temperature, and differences in solder paste formulation. Four different lead-free solder paste samples were used to produce solder bumps on a number of test boards, using surface mount reflow soldering process. Using an advanced X-ray inspection system void percentages were measured for three different size and shape solder bumps. Results indicate that the voiding in solder joint is strongly influenced by solder bump size and shape, with voids found to have increased when bump size decreased. A longer soaking period during reflow stage has negatively affectedsolder voids. Voiding was also accelerated with smaller solder particles in solder paste.

Impurity evaporation and void formation in Sn/Cu solder joints

2019 ◽  
Vol 225 ◽  
pp. 153-158 ◽  
Author(s):  
Hsuan-Ling Hsu ◽  
Hsuan Lee ◽  
Chi-Wei Wang ◽  
Chenju Liang ◽  
Chih-Ming Chen
Keyword(s):  
Solder Joints ◽  
Void Formation

Study of void formation due to electromigration in flip-chip solder joints using Kelvin bump probes

2006 ◽  
Vol 89 (3) ◽  
pp. 032103 ◽  
Author(s):  
Y. W. Chang ◽  
S. W. Liang ◽  
Chih Chen
Keyword(s):  
Flip Chip ◽  
Solder Joints ◽  
Void Formation

Relation between Kirkendall voids and intermetallic compound layers in the SnAg/Cu solder joints

2011 ◽  
Vol 23 (1) ◽  
pp. 124-129 ◽  
Author(s):  
Chun Yu ◽  
Yang Yang ◽  
Kaiyun Wang ◽  
Jijin Xu ◽  
Junmei Chen ◽  
...  
Keyword(s):  
Intermetallic Compound ◽  
Solder Joints ◽  
Kirkendall Voids
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