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.

A study on the effects of electrical and thermal stresses on void formation and migration lifetime of Sn3.0Ag0.5Cu solder joints

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yanruoyue Li ◽  
Guicui Fu ◽  
Bo Wan ◽  
Zhaoxi Wu ◽  
Xiaojun Yan ◽  
...  
Keyword(s):  
Solder Joint ◽  
Thermal Stresses ◽  
Solder Joints ◽  
Void Formation ◽  
Model Parameters ◽  
Time To Failure ◽  
Current Crowding ◽  
Theoretical Derivation ◽  
Content Type ◽  
And Migration

Purpose The purpose of this study is to investigate the effect of electrical and thermal stresses on the void formation of the Sn3.0Ag0.5Cu (SAC305) lead-free ball grid array (BGA) solder joints and to propose a modified mean-time-to-failure (MTTF) equation when joints are subjected to coupling stress. Design/methodology/approach The samples of the BGA package were subjected to a migration test at different currents and temperatures. Voltage variation was recorded for analysis. Scanning electron microscope and electron back-scattered diffraction were applied to achieve the micromorphological observations. Additionally, the experimental and simulation results were combined to fit the modified model parameters. Findings Voids appeared at the corner of the cathode. The resistance of the daisy chain increased. Two stages of resistance variation were confirmed. The crystal lattice orientation rotated and became consistent and ordered. Electrical and thermal stresses had an impact on the void formation. As the current density and temperature increased, the void increased. The lifetime of the solder joint decreased as the electrical and thermal stresses increased. A modified MTTF model was proposed and its parameters were confirmed by theoretical derivation and test data fitting. Originality/value This study focuses on the effects of coupling stress on the void formation of the SAC305 BGA solder joint. The microstructure and macroscopic performance were studied to identify the effects of different stresses with the use of a variety of analytical methods. The modified MTTF model was constructed for application to SAC305 BGA solder joints. It was found suitable for larger current densities and larger influences of Joule heating and for the welding ball structure with current crowding.

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.

Formation and Evolution of Intermetallic Compounds in Solder Joint for Electronic Interconnect

2011 ◽  
Vol 687 ◽  
pp. 80-84
Author(s):  
Chang Hua Du ◽  
Hai Jian Zhao ◽  
Li Meng Yin ◽  
Fang Chen
Keyword(s):  
Mechanical Properties ◽  
Solder Joint ◽  
Intermetallic Compounds ◽  
Isothermal Aging ◽  
Solder Joints ◽  
Growth Behavior ◽  
Electronic Products ◽  
Formation And Evolution ◽  
Kirkendall Voids ◽  
Reliability Of Solder Joints

As solder joints become increasingly miniaturized to meet the severe demands of future electronic packaging, the thickness of intermetallic compounds (IMC) in solder joint continuously decreases, while, the IMC proportion to the whole solder joint increases. So IMC plays a more and more important role in the reliability of microelectronic structure and microsystems. In this paper, the formation and growth behavior, along with the composition of IMC at the interface of Sn-based solders/Cu substrate in soldering were reviewed comprehensively. The effect of isothermal aging, thermal-shearing cycling and electromigration on the interfacial IMC growth and evolution were also presented. Furthermore, the formation mechanism of Kirkendall voids during thermal aging was introduced. In addition, the effect of the interfacial IMC on mechanical properties of solder joints was in-depth summarized. Adopting an appropriate flux to control the thickness of the IMC to improve the reliability of solder joints and electronic products was proposed in the end of this paper.

Additive Effect of Kirkendall Void Formation in Sn-3.5Ag Solder Joints on Common Substrates

2007 ◽  
Vol 37 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Feng Gao ◽  
Hiroshi Nishikawa ◽  
Tadashi Takemoto
Keyword(s):  
Solder Joints ◽  
Void Formation ◽  
Kirkendall Void ◽  
Additive Effect

Effect of Fe content on the interfacial reliability of SnAgCu/Fe-Ni solder joint

2013 ◽  
Vol 2013 (1) ◽  
pp. 000109-000114
Author(s):  
Hao Zhang ◽  
Qing-Sheng Zhu ◽  
Zhi-Quan Liu ◽  
Li Zhang ◽  
Hongyan Guo ◽  
...  
Keyword(s):  
High Temperature ◽  
Solder Joint ◽  
Solder Joints ◽  
Temperature Cycling ◽  
Growth Speed ◽  
Fe Content ◽  
Ball Shear Test ◽  
High Temperature Storage ◽  
Interfacial Reliability ◽  
Temperature Storage

Fe-Ni films with compositions of Fe-75Ni, Fe-50Ni, and Fe-30Ni were used as under bump metallization (UBM) to evaluate the interfacial reliability of SnAgCu/Fe-Ni solder joints through ball shear test, high temperature storage, as well as temperature cycling. The shear strength for Fe-75Ni, Fe-50Ni, and Fe-30Ni solder joints after reflow were 42.57, 53.94, 53.98 MPa respectively, which are all satisfied with the requirement of industrialization (>34.3 MPa ). High temperature storage was conducted at 150°C and 200°C respectively. It was found that higher Fe content in Fe-Ni layer had the ability to inhibit the mutual diffusion at interface region at 150°C, and the growth speed of intermetallic compound (IMC) decreased with the increase of Fe concentration. When stored at 200°C, the thickness of IMC would reach a limitation for all these three films after 4 days, and cracks occurred at the interface between IMC and Fe-Ni layer. Temperature cycling tests revealed that SnAgCu/Fe-50Ni solder joint had the lowest failure rate (less than 10%), which has the best interfacial reliability among three compositions.

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.

Effects of Ag on the Kirkendall void formation of Sn–xAg/Cu solder joints

2010 ◽  
Vol 108 (8) ◽  
pp. 083532 ◽  
Author(s):  
Sunghwan Kim ◽  
Jin Yu
Keyword(s):  
Solder Joints ◽  
Void Formation ◽  
Kirkendall Void
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