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.

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.

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.

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.

Inhibiting the Re-Deposition of AuSn4 on Au/Ni Metallization Pads by Varying the Accessibility of Cu in Isothermally Aged SAC305 Solder Joints

2013 ◽  
Author(s):  
Subhasis Mukherjee ◽  
Abhijit Dasgupta ◽  
Julie Silk ◽  
Lay-ling Ong
Keyword(s):  
Solid State ◽  
Solder Joint ◽  
Barrier Layer ◽  
Solder Joints ◽  
Circuit Board ◽  
Nickel Layer ◽  
Gold Content ◽  
Sac305 Solder ◽  
Lap Shear ◽  
Sac Solder

Electroplated Ni/Au over Cu is a popular metallization for printed circuit board (PCB) finish as well as for component leads, especially for wire-bondable high frequency packages, where the gold thickness (≥ 20 μinches) requirement is high for wire bonding. Redeposition of bulk AuSn4 intermetallic compound (IMC) at Au/Ni contact pads of isothermally conditioned SnAgCu (SAC) solder joints is a critical reliability concern in these packages because the interfacial layer between redeposited AuSn4 IMC and initially formed IMC during reflow at the contact pad after reflow is brittle in nature. Redeposition of bulk AuSn4 IMC in Pb-free SAC solder joints (most popularly SAC305) is also believed to be dependent on the degree of access to copper. This study examines the effect of varying gold content (2–5 nominal weight-%) in the solder joint and accessibility to copper (by presence or absence of nickel barrier layer on top of Cu plating) on redeposition of AuSn4 IMCs at the interface of isothermally aged SAC305 solder joints for 720 hours at 121°C (0.8*Tmelt). The modified lap shear Iosipescu specimens used for the study are divided into two batches: i] In the first batch, both the copper platens to be soldered are electroplated with Au and Ni. Ni barrier layers are used to completely stop the solder from accessing the Cu in the substrate ii] In the second batch, one Cu platen is electroplated with Au and Ni barrier layer but the other platen is electroplated only with copper (no Nickel layer), to allow accessibility of Cu from the substrate. Representative solder joints from above two batches are then cross-sectioned and analyzed using environmental scanning electron microscopy (ESEM) and energy-dispersive x-ray spectroscopy (EDX) to investigate the composition, thickness and morphology of both bulk and interfacial IMCs. The first phase to form at the interface of the first batch of specimens after initial reflow is Ni3Sn4/(Ni,Cu)3Sn4. During the subsequent solid-state annealing, the redeposition of AuSn4 occurred in systems plated with Au/Ni on both sides. Contrarily, in the second batch when the solder joint has copper access from one side of the joint, the first intermetallic after reflow to form is (Cu,Ni,Au)6Sn5/(Cu,Au)6Sn5 and no redeposition of AuSn4 is observed after solid state annealing except for the solder joint containing nominal 5wt-% of Au.

Effects of Temperature–Humidity Treatment on Bending Reliability of Epoxy Sn–58Bi Solder with Electroless Nickel Immersion Gold (ENIG) and Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG) Surface Finishes

2020 ◽  
Vol 12 (4) ◽  
pp. 564-570
Author(s):  
Haksan Jeong ◽  
Choong-Jae Lee ◽  
Woo-Ram Myung ◽  
Kyung Deuk Min ◽  
Seung-Boo Jung
Keyword(s):  
Intermetallic Compound ◽  
Solder Joint ◽  
Solder Joints ◽  
Solder Matrix ◽  
Electroless Nickel ◽  
Bending Test ◽  
Three Point Bending ◽  
Electroless Nickel Immersion Gold ◽  
Surface Finishes ◽  
Effects Of Temperature

An epoxy Sn–58wt.%Bi solder joint was evaluated by a three-point bending test with electroless nickel immersion gold (ENIG) and electroless nickel electroless palladium immersion gold (ENEPIG) surface finishes aged at 85 °C and 85% relative humidity. Scanning electron microscopy and electron probe microanalysis were carried out to study intermetallic compound variation. The morphology, total thickness, and chemical composition of intermetallic compound in epoxy Sn58Bi solder joints were the same as those of Sn–58wt.%Bi solder joints with each surface finish. The average number of bending-to-failure cycles for the epoxy Sn–58wt.%Bi solder/ENIG joints and epoxy Sn–58wt.%Bi solder/ENEPIG was more than 4000 and 5000, respectively. The average number of bending-to-failure cycles of the epoxy Sn–58wt.%Bi solder joint decreased with increasing age. Three-point bending reliability of epoxy Sn–58wt.%Bi solder joints was higher than that of Sn–58wt.%Bi solder with both surface finishes. Cracking of all solder joints subjected to as-reflowed was propagated through the solder matrix. However, after aging for 1000 h, cracking occurred primarily between intermetallic compound layers.

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