Evolution Modes and Self-healing Phenomenon of Kirkendall Voids at the Sn/Cu Solder Joints

2018 ◽  
pp. 129-137
Author(s):  
Shaofeng Yang ◽  
Mengjia Xu ◽  
Chun Yu
Keyword(s):  
Solder Joints ◽  
Self Healing ◽  
Kirkendall Voids

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

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.

Secondary IMC formation induced by Kirkendall voiding in Cu/Sn–3.5Ag solder joints

2010 ◽  
Vol 25 (9) ◽  
pp. 1854-1858 ◽  
Author(s):  
S.H. Kim ◽  
Jin Yu
Keyword(s):  
Solder Joints ◽  
Aging Treatment ◽  
Atomic Ratio ◽  
Cross Sectional ◽  
Section Area ◽  
Solder Balls ◽  
Kirkendall Voids ◽  
Sulfopropyl Disulfide ◽  
Scanning Electron ◽  
Subsequent Diffusion

In this investigation on the formation of multiple-layered Kirkendall voids at Cu/Sn–3.5Ag solder joints, Sn–3.5Ag solder balls were reacted with Cu under bump metallurgy (UBM), which was electroplated using bis-sodium sulfopropyl–disulfide, C6H12O6S4Na2 (SPS) additive. The sequence of multilayer Kirkendall voids and Cu–Sn IMC (intermetallic compounds) formations are explained with the aid of cross-sectional scanning electron microscopy (SEM) micrographs and schematic diagrams. During the aging treatment at 150 °C, layers of Cu6Sn5/Cu3Sn formed at the solder joints and Kirkendall voids nucleated at the Cu3Sn/Cu interface as a result of the segregation of residual S originating from SPS. However, with Kirkendall void growth, the net section area of the Cu/Cu3Sn interface decreased and the Cu flux into Cu3Sn was inhibited. As the atomic ratio of Cu against Sn in the Cu3Sn dropped, transformation of Cu3Sn into Cu6Sn5 ensued. Subsequent diffusion of Sn atoms into the remaining Cu UBM through the remaining ligament of the Cu6Sn5/Cu interface precipitated secondary Cu3Sn beneath the primary Cu3Sn/Cu interface, and the secondary Kirkendall voids formed at the new Cu3Sn/Cu interface and so on.

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.

Formation of Kirkendall Voids at Low and High Aging Temperature in the Sn-0.7Cu-1.0wt.%Si3N4/Cu Solder Joints

2015 ◽  
Vol 1107 ◽  
pp. 577-581
Author(s):  
Norainiza Saud ◽  
Flora Somidin ◽  
Najib Saedi Ibrahim ◽  
Mohd Arif Anuar Mohd Salleh
Keyword(s):  
Solid State ◽  
Low Temperature ◽  
Aging Time ◽  
Aging Temperature ◽  
Solder Joints ◽  
The Other ◽  
Imcs Layer ◽  
High Aging Temperature ◽  
Kirkendall Voids ◽  
Soldered Joint

The intermetallic compounds (IMCs) layer formed between Sn-0.7Cu-1.0wt.%Si3N4(SC-1.0SN) solder and Cu-substrate were investigated through isothermal solid-state aging. The SC-1.0SN/Cu solder joints were aged at 50°C and 150°C for 24h, 240h, 480h and 720h duration after reflow. The as-soldered joint IMC formed at interface was Cu6Sn5. In addition, only Cu6Sn5layer was observed at the interface of the samples aged at low temperature of 50°C although the aging duration was prolonged up to 720h and has begun to increase in thickness. On the other hand, the Cu3Sn layer was clearly observed in the sample of aged at 150°C up to 240h. However, at least no voids were vividly observed in the 50°C aged samples, while kirkendall voids were clearly found in Cu3Sn layer of samples aged at 150°C up to 480h of aging time will be discussed further.

Kirkendall voids in the intermetallic layers of solder joints in MEMS

2009 ◽  
Vol 45 (3) ◽  
pp. 827-831 ◽  
Author(s):  
Kerstin Weinberg ◽  
Thomas Böhme ◽  
Wolfgang H. Müller
Keyword(s):  
Solder Joints ◽  
Kirkendall Voids ◽  
Intermetallic Layers

Formation and behavior of Kirkendall voids within intermetallic layers of solder joints

2011 ◽  
Vol 22 (7) ◽  
pp. 703-716 ◽  
Author(s):  
Doosoo Kim ◽  
Jong-hyeon Chang ◽  
Jungil Park ◽  
James Jungho Pak
Keyword(s):  
Solder Joints ◽  
Kirkendall Voids ◽  
And Behavior ◽  
Intermetallic Layers

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.

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