Failure Modes of Flip Chip Solder Joints Under High Electric Current Density

2004 ◽  
Vol 127 (2) ◽  
pp. 157-163 ◽  
Author(s):  
C. Basaran ◽  
H. Ye ◽  
D. C. Hopkins ◽  
D. Frear ◽  
J. K. Lin
Keyword(s):  
Solder Joint ◽  
Current Density ◽  
Flip Chip ◽  
Failure Modes ◽  
Solder Joints ◽  
Void Nucleation ◽  
Electrical Current ◽  
Nucleation And Growth ◽  
Joint Interface ◽  
Void Nucleation And Growth

The failure modes of flip chip solder joints under high electrical current density are studied experimentally. Three different failure modes are reported. Only one of the failure modes is caused by the combined effect of electromigration and thermomigration, where void nucleation and growth contribute to the ultimate failure of the module. The Ni under bump metallization–solder joint interface is found to be the favorite site for void nucleation and growth. The effect of pre-existing voids on the failure mechanism of a solder joint is also investigated

scholarly journals The Modified Void Nucleation and Growth Model (MNAG) for Damage Evolution in BCC Ta

2021 ◽  
Vol 11 (8) ◽  
pp. 3378
Author(s):  
Jie Chen ◽  
Darby J. Luscher ◽  
Saryu J. Fensin
Keyword(s):  
Growth Model ◽  
Damage Evolution ◽  
Volume Fraction ◽  
Void Nucleation ◽  
Nucleation And Growth ◽  
Void Coalescence ◽  
Hydrodynamic Simulations ◽  
Void Evolution ◽  
Void Nucleation And Growth ◽  
Nucleation Growth

A void coalescence term was proposed as an addition to the original void nucleation and growth (NAG) model to accurately describe void evolution under dynamic loading. The new model, termed as modified void nucleation and growth model (MNAG model), incorporated analytic equations to explicitly account for the evolution of the void number density and the void volume fraction (damage) during void nucleation, growth, as well as the coalescence stage. The parameters in the MNAG model were fitted to molecular dynamics (MD) shock data for single-crystal and nanocrystalline Ta, and the corresponding nucleation, growth, and coalescence rates were extracted. The results suggested that void nucleation, growth, and coalescence rates were dependent on the orientation as well as grain size. Compared to other models, such as NAG, Cocks–Ashby, Tepla, and Tonks, which were only able to reproduce early or later stage damage evolution, the MNAG model was able to reproduce all stages associated with nucleation, growth, and coalescence. The MNAG model could provide the basis for hydrodynamic simulations to improve the fidelity of the damage nucleation and evolution in 3-D microstructures.

Electromigration in Solder Joints for High Temperature Flip-Chip Application

2011 ◽  
Vol 2011 (DPC) ◽  
pp. 002481-002506
Author(s):  
Mathias Nowottnick ◽  
Andreas Fix
Keyword(s):  
High Temperature ◽  
Current Density ◽  
Flip Chip ◽  
Solder Joints ◽  
Metallographic Analysis ◽  
Solder Alloys ◽  
Directed Movement ◽  
Cross Sectional ◽  
Current Densities ◽  
And Migration

The electromigration effects in chip metallization and wire bonds are well known and detailed investigated. Current density could be extremely high because of the small size of the cross sectional area of conductors. This can cause a migration of metal atoms toward the electrical field, so current densities up to 106 A/cm2 are possible. In comparison with chip structures are the usual solder joints of flip chips relatively thick. But the homologue temperature of solder alloys, typically based on tin, is also much higher than for gold or aluminum wires. For instance a SAC solder alloy is naturally preheated up to 0.6 homologue temperature, for high temperature application with 125 °C operating temperature even more than 0.8. This means, that atoms are very agile and a directed movement needs only lower field strength. Additionally is the specific resistance of solder alloys tenfold higher than for aluminum, copper or silver. So is the self-heating of solder joints not negligible. This contribution shows the test results of flip-chip assemblies, loaded with different current densities and stored at 125 °C ambient temperature. At the end of life of a significant number of test chips, a metallographic analysis shows the causing failure effects and weak spots of assemblies. Accompanying simulations help to explain the interaction between current density and migration effects.

4D X-ray tomography characterization of void nucleation and growth during deformation of strontium-added AZ31 alloys

2020 ◽  
Vol 797 ◽  
pp. 140081
Author(s):  
Javad Samei ◽  
Alireza Sadeghi ◽  
Hossein Mortezapour ◽  
Saeid Salavati ◽  
Maedeh Amirmaleki ◽  
...  
Keyword(s):  
Void Nucleation ◽  
Nucleation And Growth ◽  
X Ray ◽  
Void Nucleation And Growth

scholarly journals Void Nucleation, and Growth during Tensile Deformation of Nanoscale Precipitated Steel and Bainitic Steel

2019 ◽  
Vol 59 (7) ◽  
pp. 1362-1368
Author(s):  
Yasutaka Mugita ◽  
Masatoshi Aramaki ◽  
Masayuki Yamamoto ◽  
Akihisa Takeuchi ◽  
Miyuki Takeuchi ◽  
...  
Keyword(s):  
Tensile Deformation ◽  
Void Nucleation ◽  
Nucleation And Growth ◽  
Bainitic Steel ◽  
Void Nucleation And Growth

Failure Mechanism of Electromigration in Solder Joint

2008 ◽  
Vol 44-46 ◽  
pp. 905-910 ◽  
Author(s):  
Yu Dong Lu ◽  
Xiao Qi He ◽  
Yun Fei En ◽  
Xin Wang
Keyword(s):  
Solder Joint ◽  
Flip Chip ◽  
Solder Joints ◽  
High Current Density ◽  
Electron Flow ◽  
Design Rule ◽  
Bottom Surface ◽  
Constant Density ◽  
Linear Change ◽  
Void Migration

In advanced electronic products, electromigration-induced failure is one of the most serious problems in fine pitch flip chip solder joints because the design rule in devices requires high current density through small solder joints for high performance and miniaturization. The failure mode induced by electromigration in the flip chip solder joint is unique, owing to the loss of under bump metallurgy (UBM) and the interfacial void formation at the cathode contact interface. In this study, Electromigration of flip chip solder joints has been investigated under a constant density of 2.45×104 A/cm2 at 120 °C. The in-situ marker displacements during the electromigration test was measured and found to show a rough linear change as a function of time. Scanning electron microscopic images of the cross section of samples showed the existence of voids at the interface between Al interconnection and under bump metallurgy. The void movement was matched with the marker displacements during the electromigration test, and voids moved to the cathode interface between Al interconnection and under bump metallurgy in the downward electron flow (from chip to substrate) joint. The mechanism of electromigration-induced void migration and failure in the flip chip are discussed. During electromigration, a flux of atoms is driven from the cathode to the anode or a flux of vacancies in the opposite direction. It can lead to two possible mechanisms of void migration. First, if we regard the void as a rigid marker of diffusion, it will be displaced towards the cathode by the atomic flux in the electromigration, Second, if we consider surface diffusion on the void surface, electromigration will drive atoms on the top surface of the void to the bottom surface of the void, and consequently the void will move towards the cathode.

Study on the Mechanical Bend Fatigue of Micro-Joining Soldered Joint with Lead-Free Solder

2007 ◽  
Vol 353-358 ◽  
pp. 2573-2576 ◽  
Author(s):  
Fang Juan Qi ◽  
Li Xing Huo ◽  
Ya Ping Ding ◽  
Zhan Lai Ding
Keyword(s):  
Solder Joint ◽  
Failure Modes ◽  
Lead Free ◽  
Joint Interface ◽  
Similar Data ◽  
Lead Free Solder ◽  
Fatigue Reliability ◽  
Free Solder ◽  
Halogen Free ◽  
Soldered Joint

In recent years, several electronics manufacturers have been working toward introducing lead-free solder and halogen-free print circuit boards (PCBs) into their products. The key drivers for the change in materials have been the impending environmental legislations, particularly in Europe and Japan as well as the market appeal of ‘green’ products. The reliability of the new materials is an important determinant of the pace of adoption. Fairly extensive mechanical fatigue reliability data is also available for micro-joining soldered joint such as Ball Grid Array (BGA) with tin-lead solder. However, similar data is not available for BGAs assembled with lead-free solder. Mechanical reliability is a critical indicator for phone and BGA survival during repeated keypress, and to some extent during drop. In this paper, the mechanical bend fatigue of BGAs with tin-lead and lead-free solders on halogen-free substrates are examined respectively. A tin-silver-copper alloy was used as lead-free solder due to its increasing acceptance, and the results were compared to those from samples assembled with Sn63Pb37 solder. The reliability was examined at both low cycle and high cycle fatigue. Results show that the mechanical bend fatigue reliability of BGA assemblies with lead-free solder is higher than that of BGA assembly with tin-lead solder. Cross section and failure analysis indicated two distinct failure modes - solder joint and PCB failure. A 3-D parametric finite element model was developed to correlate the local PCB strains and solder joint plastic strains with the fatigue life of the assembly. The intermetallic compoumd (IMC) of micro-joining joint interface was analysised in the future in order to study on the effect of IMC on the reliability.

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