Correlation Between Chemical Reaction and Brittle Fracture Found in Electroless Ni(P)/immersion gold–solder Interconnection

2005 ◽  
Vol 20 (8) ◽  
pp. 1931-1934 ◽  
Author(s):  
Yoon-Chul Sohn ◽  
Jin Yu
Keyword(s):  
Intermetallic Compound ◽  
Brittle Fracture ◽  
Solder Joint ◽  
Chemical Reaction ◽  
Solder Joints ◽  
Interfacial Fracture ◽  
Solder Interconnection ◽  
Failure Locus ◽  
Electroless Ni ◽  
First Time

Occurrence of brittle interfacial fracture at an electroless Ni(P)/immersion gold–solder joint has long been a serious problem not yet fully understood. In our previous report on the electroless Ni(P) [J. Mater. Res.19,2428 (2004)], it was shown that crystallization of the Ni(P) film and growth of the Ni3SnP layer were accelerated after the intermetallic compound (IMC) spalling, and accurate failure locus of the brittle fracture due to so-called “IMC spalling induced microstructure degradation of the Ni(P) film” is presented for the first time in this communication. For Sn–3.0Ag–0.5Cu solder joints, (Ni,Cu)3Sn4and/or (Cu,Ni)6Sn5ternary IMCs formed at the interface, and neither spalling nor interfacial fracture was observed. For Sn–3.5Ag joints, Ni3Sn4compound formed, and the brittle fracture occurred through the Ni3SnP layer in the solder pads where Ni3Sn4had spalled. Since the Ni3SnP layer is getting thicker during or after Ni3Sn4spalling, control of IMC spalling is crucial to ensure the reliability of Ni(P)/solder system.

Solder electromigration behavior in Cu/electroless Ni–P plating/Sn–Cu based joint system at low current densities

2015 ◽  
Vol 2015 (1) ◽  
pp. 000141-000146 ◽  
Author(s):  
Takuya Kadoguchi ◽  
Kimihiro Yamanaka ◽  
Shijo Nagao ◽  
Katsuaki Suganuma
Keyword(s):  
Intermetallic Compound ◽  
Solder Joint ◽  
Barrier Layer ◽  
Solder Joints ◽  
Great Influence ◽  
Joint System ◽  
Barrier Layers ◽  
Current Densities ◽  
Electroless Ni

Electromigration (EM) in solder joints has great influence on their reliability. Nevertheless, few reports have been published on the EM in solder joints with Ni–P barrier layers at lower current densities less than 10 kA/cm2. In the present study, EM in Cu/Ni–P/Sn–0.7Cu/Ni–P/Cu joints was investigated at 150 °C with current densities of 5.0 and 7.5 kA/cm2. The breakdown mode was open failure of the solder joint on the cathode. It was found that Ni in the Ni–P barrier layer diffused toward the anode, resulting in a thicker P-rich layer, which caused the cracks and the delamination of the P-rich layer. Additionally, the diffusion of Sn detached the solder from the Ni3SnP intermetallic compound on the cathode.

Effect of Underfill Entrapment on the Reliability of Flip-Chip Solder Joint

2004 ◽  
Vol 126 (4) ◽  
pp. 541-545 ◽  
Author(s):  
Y. C. Chan ◽  
M. O. Alam ◽  
K. C. Hung ◽  
H. Lu ◽  
C. Bailey
Keyword(s):  
Solder Joint ◽  
Flip Chip ◽  
Solder Joints ◽  
High Volume ◽  
Fatigue Lifetime ◽  
Solder Interconnection ◽  
Thermal Fatigue Life ◽  
Solder Bumps ◽  
First Time ◽  
Good Agreement

The application of underfill materials to fill up the room between the chip and substrate is known to substantially improve the thermal fatigue life of flip chip solder joints. Nowadays, no-flow underfill materials are gaining much interest over traditional underfill as the application and curing of this type of underfill can be undertaken before and during the reflow process and thus aiding high volume throughput. However, there is always a potential chance of entrapping no-flow underfill in the solder joints. This work, attempts to find out the extent of underfill entrapment in the solder joints and its reliability effect on the flip chip packages. Some unavoidable underfill entrapments at the edges of the joint between solder bumps and substrate pads are found for certain solder joints whatever bonding conditions are applied. It is interesting to report for the first time that partial underfill entrapment at the edges of the solder joint seems to have no adverse effect on the fatigue lifetime of the samples since most of the first solder joint failure in the no-flow flip chip samples during thermal cycling are not at the site of solder interconnection with underfill entrapment. Our modeling results show good agreement with the experiment that shows underfill entrapment can actually increase the fatigue lifetime of the no-flow flip chip package.

Microstructure Evolution of Sn-2.5Ag-2.0Ni Solder Joint with Various Ni Platings on SiCp/Al Composites

2010 ◽  
Vol 638-642 ◽  
pp. 3811-3818
Author(s):  
Mao Wu ◽  
Xin Bo He ◽  
Shu Bin Ren ◽  
Ming Li Qin ◽  
Xuan Hui Qu
Keyword(s):  
Growth Rate ◽  
Shear Strength ◽  
Intermetallic Compound ◽  
Solder Joint ◽  
Aging Time ◽  
Microstructure Evolution ◽  
Thermal Stresses ◽  
Solder Joints ◽  
Electroless Ni

A novel Sn-2.5Ag-2.0Ni alloy has been developed for soldering of SiCp/Al composites substrate with various types of Ni coatings. An investigation about electroplated Ni layer, electroless Ni-5 wt.% P, Ni-10wt.% P and Ni-B layers has been carried out. It is found that the solder joints possess a single intermetallic compound (IMC) Ni3Sn4, which coarsens with an increase in aging time. The formation of Ni2SnP has been observed to significantly affect the reliability of the solder joints. But the formation of Ni2SnP can be suppressed by lowering the P contents in as-deposited Ni coatings. It has been also found that the thermal stresses generated in solder joint increases with the decrease of P contents in Ni-P layer. Furthermore, the concentration of thermal stresses in the electroplated Ni solder joint is found to be higher than that in other three electroless Ni layers. Out of four as-deposited Ni coatings, the Ni-B layer exhibits good wettability with solder and low IMC growth rate during aging. Also, the shear strength of solder joint decreases with an increase in aging time and Ni-B solder joint demonstrates the highest shear strength after long term aging.

Interfacial Reaction of Electroless Ni-P Plating with Sn-3.5Ag (-Co) Solder

2008 ◽  
Vol 580-582 ◽  
pp. 243-246 ◽  
Author(s):  
Hiroshi Nishikawa ◽  
Akira Komatsu ◽  
Tadashi Takemoto
Keyword(s):  
Intermetallic Compound ◽  
Interfacial Reaction ◽  
Fracture Mode ◽  
Joint Strength ◽  
Solder Bump ◽  
Solder Joints ◽  
Pull Strength ◽  
Electroless Ni

The reaction between Sn-Ag (-Co) solder and electroless Ni-P plating was investigated in order to clarify the effect of the addition of Co to Sn-Ag solder on the formation of intermetallic compound (IMC) at the interface and the joint strength at the interface. Sn-Ag-Co solder was specially prepared. The results show that there is little effect of the addition of Co to the Sn-Ag solder on the IMC formation and the thickness of the IMC at the interface. For the pull strength of the solder bump joint, the addition of Co to the solder didn’t strongly affect the pull strength of the solder joints, but it affected the fracture mode of the solder joints.

Effect of intermetallic compound layer thickness on the shear strength of 1206 chip resistor solder joint

2015 ◽  
Vol 27 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Peter K. Bernasko ◽  
Sabuj Mallik ◽  
G. Takyi
Keyword(s):  
Shear Strength ◽  
Intermetallic Compound ◽  
Solder Joint ◽  
Layer Thickness ◽  
Solder Joints ◽  
Ageing Time ◽  
Circuit Board ◽  
Intermetallic Compound Layer ◽  
Content Type ◽  
Surface Mount

Purpose – The purpose of this paper is to study the effect of intermetallic compound (IMC) layer thickness on the shear strength of surface-mount component 1206 chip resistor solder joints. Design/methodology/approach – To evaluate the shear strength and IMC thickness of the 1206 chip resistor solder joints, the test vehicles were conventionally reflowed for 480 seconds at a peak temperature of 240°C at different isothermal ageing times of 100, 200 and 300 hours. A cross-sectional study was conducted on the reflowed and aged 1206 chip resistor solder joints. The shear strength of the solder joints aged at 100, 200 and 300 hours was measured using a shear tester (Dage-4000PXY bond tester). Findings – It was found that the growth of IMC layer thickness increases as the ageing time increases at a constant temperature of 175°C, which resulted in a reduction of solder joint strength due to its brittle nature. It was also found that the shear strength of the reflowed 1206 chip resistor solder joint was higher than the aged joints. Moreover, it was revealed that the shear strength of the 1206 resistor solder joints aged at 100, 200 and 300 hours was influenced by the ageing reaction times. The results also indicate that an increase in ageing time and temperature does not have much influence on the formation and growth of Kirkendall voids. Research limitations/implications – A proper correlation between shear strength and fracture mode is required. Practical implications – The IMC thickness can be used to predict the shear strength of the component/printed circuit board pad solder joint. Originality/value – The shear strength of the 1206 chip resistor solder joint is a function of ageing time and temperature (°C). Therefore, it is vital to consider the shear strength of the surface-mount chip component in high-temperature electronics.

Cracking of the Intermetallic Compound Layer in Solder Joints Under Drop Impact Loading

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Tong An ◽  
Fei Qin
Keyword(s):  
Intermetallic Compound ◽  
Solder Joint ◽  
Impact Loading ◽  
Driving Force ◽  
Solder Joints ◽  
Compound Layer ◽  
Drop Impact ◽  
Lead Free ◽  
Intermetallic Compound Layer ◽  
Crack Driving Force

The significant difference between failure modes of lead-containing and lead-free solder joints under drop impact loading remains to be not well understood. In this paper, we propose a feasible finite element approach to model the cracking behavior of solder joints under drop impact loading. In the approach, the intermetallic compound layer/solder bulk interface is modeled by the cohesive zone model, and the crack driving force in the intermetallic compound layer is evaluated by computing the energy release rate. The numerical simulation of a board level package under drop impact loading shows that, for the lead-containing Sn37Pb solder joint, the damage in the vicinity of the intermetallic compound layer initiates earlier and is much greater than that in the lead-free Sn3.5Ag solder joint. This damage relieves the stress in the intermetallic compound layer and reduces the crack driving force in it and consequently alleviates the risk of the intermetallic compound layer fracturing.

Plastic Strain Distribution as a Precursor for Transition From Ductile to Brittle Failure in Lead-Free Solder Joints

2009 ◽  
Author(s):  
Feng Gao ◽  
Jianping Jing ◽  
Frank Z. Liang ◽  
Richard L. Williams ◽  
Jianmin Qu
Keyword(s):  
Brittle Fracture ◽  
Plastic Strain ◽  
Solder Joint ◽  
Failure Mode ◽  
Strain Distribution ◽  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Loading Rates ◽  
Free Solder

One of the major failure modes in lead-free solder joints is the brittle fracture at the solder/Cu pad interface under dynamic loading conditions. Such brittle fracture often leads to catastrophic premature failure of portable electronic devices. Therefore, it is desirable to design the package and the solder joints in such a way that brittle interfacial fracture can be avoided during drop test. To develop such design guidelines, we studied in this paper the dynamic failure of a single solder joint (SSJ). The SSJs with different geometry and substrate surface finish were prepared by laser-cutting from a BGA package assembled on a printed circuit board (PCB). The SSJs were tested under various shear loading rates, ranging from 5 mm/s to 500 mm/s. In conjunction with the experimental tests, finite element analyses (FEA) of these SSJ samples subjected to various loading rates were also conducted. Results from both experimental testing and numerical simulations show that the distribution of plastic strain near the solder/IMC interface is a key indictor of the failure mode. For a given sample geometry and loading rate, if the maximum solder plastic strain lies near the solder/IMC interface, the failure will be more likely to be ductile failure within the solder alloy. On the other hand, if the maximum plastic strain is mainly located at the edge of the interface between solder and the IMC layer with very little plasticity within the solder near the interface, brittle fracture of the IMC/Cu interface will be more likely to occur. Since numerically computing the plastic strain distribution in a solder joint is much easier than predicting joint failure, results of this study provide us with an effective means to predict the type of failure mode of a solder joint under dynamic loading.

Effect of Solder Joint Thickness on Intermetallic Compound Growth Rate of Cu/Sn/Cu Solder Joints During Thermal Aging

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Yan Zhu ◽  
Fenglian Sun
Keyword(s):  
Growth Rate ◽  
Intermetallic Compound ◽  
Solder Joint ◽  
Aging Time ◽  
Thermal Aging ◽  
Solder Joints ◽  
Control Element ◽  
Joint Thickness ◽  
Intermetallic Compound Growth ◽  
Peak Value

The sandwich structure Cu/Sn/Cu solder joints with different thicknesses of the solder layers (δ) are fabricated using a reflow solder method. The microstructure and composition of the solder joints are observed and analyzed by scanning electron microscopy (SEM). Results show that the thickness of intermetallic compound (IMC) and Cu concentration in the solder layers increase with the decrease of δ after reflow. During thermal aging, the thickness of IMC does not increase according to the parabolic rule with the increase of aging time; the solder joint thickness affects markedly the growth rate of IMC layer. At the beginning of thermal aging, the growth rate of IMC in the thinner solder joints (δ ≤ 25 μm) is higher than that in the thicker ones (δ ≥ 30 μm). The growth rate of IMC (δ ≤ 25 μm) decreases in the thinner solder joints, while increases in the thicker solder joints (δ ≥ 40 μm) and is nearly invariable when the δ equals to 30 μm with aging time extending. The growth rate of IMC increases first and then decreases after reaching a peak value with the increase of δ in the later stage during aging. The main control element for IMC growth transfers from Cu to Sn with the reduction of size.

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