Effects of Bismuth Content on the Microstructure, Shear Strength and Thermal Properties of Sn-0.7Cu-0.05Ni Solder Joints

2020 ◽  
Vol 982 ◽  
pp. 115-120
Author(s):  
Phairote Sungkhaphaitoon ◽  
Tanyaporn Suwansukho
Keyword(s):  
Shear Strength ◽  
Thermal Properties ◽  
Solder Joint ◽  
Intermetallic Compounds ◽  
Interfacial Layer ◽  
Solder Joints ◽  
Peak Temperature ◽  
Cu Substrate ◽  
Bismuth Content ◽  
Pasty Range

The effects of bismuth content on the microstructure, shear strength and thermal properties of Sn-0.7Cu-0.05Ni solder joints were investigated. Adding 2 wt% elemental Bi to Sn-0.7Cu-0.05Ni solder joints reduced peak temperature by about 6.7 °C, increased pasty range by 4.2 °C and raised undercooling by 3.1 °C. The microstructure of the interfacial layer between solder and Cu substrate was composed of (Cu,Ni)6Sn5 and (Cu,Ni)3Sn intermetallic compounds (IMCs). The solder joint included a phase of SnBi and Cu6Sn5 IMCs. The addition of elemental Bi increased shear strength and suppressed the growth of IMCs in the interfacial layer of the solder joints.

Interfacial reactions of Sn–Cu and Sn–Pb–Ag solder with Au/Ni during extended time reflow in ball grid array packages

2004 ◽  
Vol 19 (10) ◽  
pp. 2897-2904 ◽  
Author(s):  
M.N. Islam ◽  
Y.C. Chan ◽  
A. Sharif
Keyword(s):  
Growth Rate ◽  
Shear Strength ◽  
Solder Joint ◽  
Intermetallic Compounds ◽  
Solder Joints ◽  
Interfacial Reactions ◽  
Extended Time ◽  
Reflow Time ◽  
Ternary Intermetallic Compounds ◽  
Ball Grid Array Packages

Lead-free solders with high Sn content cause excessive interfacial reactions at the interface with under-bump metallization during reflow. The interface formed after reflow affects the reliability of the solder joint. For this paper, we investigated the interfacial reactions of Sn0.7Cu and Sn36Pb2Ag solder on electrolytic Ni layer for different reflow times. The traditionally used Sn36Pb2Ag solder was used as a reference. It was found that during as-reflowed, the formation of Cu-rich Sn–Cu–Ni ternary intermetallic compounds (TIMCs) at the interface of Sn0.7Cu solder with electrolytic Ni is much quicker, resulting in the entrapment of some Pb (which is present as impurity in the Sn–Cu solder) rich phase in the TIMCs. During extended time of reflow, high (>30 at.%), medium (30-15 at.%) and low (<15 at.%) Cu TIMCs formed at the interface. The amount of Cu determined the growth rate of TIMCs. Cu-rich TIMCs had higher growth rate and consumed more Ni layer. By contrast, the growth rate of the Ni–Sn binary intermetallic compounds (BIMCs) in the Sn36Pb2Ag solder joint was slower, and the Ni–Sn BIMC was more stable and adherent. The dissolution rate of electrolytic Ni layer for Sn0.7Cu solder joint was higher than the Sn36Pb2Ag solder joints. Less than 3 μm of the electrolytic Ni layer was consumed during molten reaction by the higher Sn containing Sn0.7Cu solder in 180 min at 250 °C. The shear strength of Sn–Pb–Ag solder joints decreased within 30 min of reflow time from 1.938 to 1.579 kgf due to rapid formation of ternary Ni–Sn–Au compounds on the Ni–Sn BIMCs. The shear strength of Sn0.7Cu solder joint is relatively stable from 1.982 to 1.861 kgf during extended time reflow. Cu prevents the resettlement of Au at the interface. The shear strength does not depend on the thickness of intermetallic compounds (IMCs) and reflow time. Ni/Sn–Cu solder system has higher strength and can be used during prolonged reflow.

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.

scholarly journals Comprehensive Properties of a Novel Quaternary Sn-Bi-Sb-Ag Solder: Wettability, Interfacial Structure and Mechanical Properties

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 791 ◽  
Author(s):  
Kaipeng Wang ◽  
Fengjiang Wang ◽  
Ying Huang ◽  
Kai Qi
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Low Temperature ◽  
Strain Rate ◽  
Isothermal Aging ◽  
Solder Joints ◽  
Solder Matrix ◽  
Interfacial Structure ◽  
Solder Alloys ◽  
Cu Substrate

Sn-58Bi eutectic solder is the most recommended low temperature Pb-free solder but is also limited from the interfacial embrittlement of Bi segregation. Since the quaternary Sn-38Bi-1.5Sb-0.7Ag solder provides a similar melting point as Sn-58Bi eutectic, this paper systematically investigated the properties of this solder from wettability, bulk tensile properties, interfacial microstructure in solder joints with a Cu substrate, interfacial evolution in joints during isothermal aging and the shear strength on ball solder joints with effect of aging conditions. The results were also compared with Sn-58Bi solder. The wettability of solder alloys was evaluated with wetting balance testing, and the quaternary Sn-38Bi-1.5Sb-0.7Ag solder had a better wettability than Sn-58Bi solder on the wetting time. Tensile tests on bulk solder alloys indicated that the quaternary Sn-38Bi-1.5Sb-0.7Ag solder had a higher tensile strength and similar elongation compared with Sn-58Bi solder due to the finely distributed SnSb and Ag3Sn intermetallics in the solder matrix. The tensile strength of solder decreased with a decrease in the strain rate and with an increase in temperature, while the elongation of solder was independent of the temperature and strain rate. When soldering with a Cu substrate, a thin Cu6Sn5 intermetallic compound (IMC) is produced at the interface in the solder joint. Measurement on IMC thickness showed that the quaternary Sn-38Bi-1.5Sb-0.7Ag had a lower IMC growth rate during the following isothermal aging. Ball shear test on solder joints illustrated that the quaternary Sn-38Bi-1.5Sb-0.7Ag solder joints had higher shear strength than Sn-58Bi solder joints. Compared with the serious deterioration on shear strength of Sn-58Bi joints from isothermal aging, the quaternary Sn-38Bi-1.5Sb-0.7Ag solder joints presented a superior high temperature stability. Therefore, the quaternary Sn-38Bi-1.5Sb-0.7Ag solder provides better performances and the possibility to replace Sn-58Bi solder to realize low temperature soldering.

scholarly journals Shear Strength and Aging Characteristics of Sn-3.0Ag-0.5Cu/Cu Solder Joint Reinforced with ZrO2 Nanoparticles

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1295
Author(s):  
Sri Harini Rajendran ◽  
Seung Jun Hwang ◽  
Jae Pil Jung
Keyword(s):  
Shear Strength ◽  
Solder Joint ◽  
Solder Joints ◽  
Solder Matrix ◽  
Fracture Analysis ◽  
Zro2 Nanoparticles ◽  
Solder Paste ◽  
Lap Shear ◽  
Matrix Fracture ◽  
The Matrix

This study investigates the shear strength and aging characteristics of Sn-3.0Ag-0.5Cu (SAC 305)/Cu joints by the addition of ZrO2 nanoparticles (NPs) having two different particle size: 5–15 nm (ZrO2A) and 70–90 nm (ZrO2B). Nanocomposite pastes were fabricated by mechanically mixing ZrO2 NPs and the solder paste. ZrO2 NPs decreased the β-Sn grain size and Ag3Sn intermetallic compound (IMC) in the matrix and reduced the Cu6Sn5 IMC thickness at the interface of lap shear SAC 305/Cu joints. The effect is pronounced for ZrO2A NPs added solder joint. The solder joints were isothermally aged at 175 °C for 24, 48, 144 and 256 h. NPs decreased the diffusion coefficient from 1.74 × 10–16 m/s to 3.83 × 10–17 m/s and 4.99 × 10–17 m/s for ZrO2A and ZrO2B NPs added SAC 305/Cu joints respectively. The shear strength of the solder joints decreased with the aging time due to an increase in the thickness of interfacial IMC and coarsening of Ag3Sn in the solder. However, higher shear strength exhibited by SAC 305-ZrO2A/Cu joints was attributed to the fine Ag3Sn IMC’s dispersed in the solder matrix. Fracture analysis of SAC 305-ZrO2A/Cu joints displayed mixed solder/IMC mode upon 256 h of aging.

Effects of electromigration on the growth of intermetallic compounds in Cu/SnBi/Cu solder joints

2008 ◽  
Vol 23 (10) ◽  
pp. 2591-2596 ◽  
Author(s):  
X. Gu ◽  
D. Yang ◽  
Y.C. Chan ◽  
B.Y. Wu
Keyword(s):  
Activation Energy ◽  
Solder Joint ◽  
Intermetallic Compounds ◽  
Direct Current ◽  
Solder Joints ◽  
Cathode Side ◽  
Anode Side ◽  
Kinetics Parameters ◽  
Ambient Temperatures ◽  
Current Stressing

In this study, the effects of electromigration (EM) on the growth of Cu–Sn intermetallic compounds (IMCs) in Cu/SnBi/Cu solder joints under 5 × 103 A/cm2 direct current stressing at 308, 328, and 348 K were investigated. For each Cu/SnBi/Cu solder joint under current stressing, the IMCs at the cathode side grew faster than that at the anode side. The growth of these IMCs at the anode side and the cathode side were enhanced by electric current. The growth of these IMCs at the cathode followed a parabolic growth law. The kinetics parameters of the growth of the IMCs were calculated from the thickness data of the IMCs at the cathode side at different ambient temperatures. The calculated intrinsic diffusivity (D0) of the Cu–Sn IMCs was 9.91 × 10−5 m2/s, and the activation energy of the growth of the total Cu–Sn IMC layer was 89.2 kJ/mol (0.92 eV).

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.

Property of Sn-37Pb solder bumps with different diameter during thermal shock

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Guisheng Gan ◽  
Donghua Yang ◽  
Yi-ping Wu ◽  
Xin Liu ◽  
Pengfei Sun ◽  
...  
Keyword(s):  
Shear Strength ◽  
Solder Joint ◽  
Thermal Shock ◽  
Solder Joints ◽  
Test Method ◽  
Content Type ◽  
Ball Size ◽  
Solder Bumps ◽  
Free Solder ◽  
The Impact

Purpose The impact strength of solder joint under high strain rate was evaluated by board level test method. However, the impact shear test of single solder bump was more convenient and economical than the board level test method. With the miniaturization of solder joints, solder joints were more prone to failure under thermal shock and more attention has been paid to the impact reliability of solder joint. But Pb-free solder joints may be paid too much attention and Sn-Pb solder joints may be ignored. Design/methodology/approach In this study, thermal shock test between −55°C and 125°C was conducted on Sn-37Pb solder bumps in the BGA package to investigate microstructural evolution and growth mechanism of interfacial intermetallic compounds (IMCs) layer. The effects of thermal shock and ball diameter on the mechanical property and fracture behavior of Sn-37Pb solder bumps were discussed. Findings With the increase of ball size, the same change tendency of shear strength with thermal shock cycles. The shear strength of the solder bumps was the highest after reflow; with the increase of the number of thermal shocks, the shear strength of the solder bumps was decreased. But at the time of 2,000 cycles, the shear strength was increased to the initial strength. Minimum shear strength almost took place at 1,500 cycles in all solder bumps. The differences between maximum shear strength and minimum shear strength were 9.11 MPa and 16.83 MPa, 17.07 MPa and 15.59 MPa in φ0.3 mm and φ0.4 mm, φ0.5 mm and φ0.6 mm, respectively, differences were increased with increasing of ball size. With similar reflow profile, the thickness of IMC decreased as the diameter of the ball increased. The thickness of IMC was 2.42 µm and 2.17 µm, 1.63 µm and 1.77 µm with increasing of the ball size, respectively. Originality/value Pb-free solder was gradually used to replace traditional Sn-Pb solder and has been widely used in industry. Nevertheless, some products inevitably used a mixture of Sn-Pb and Pb-free solder to make the transition from Sn-Pb to Pb-free solder. Therefore, it was very important to understand the reliability of Sn-Pb solder joint and more further research works were also needed.

Effects of Sn-Ag-x leveling layers on the microstructure and mechanical properties of SnBi low-temperature solder joints

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yang Liu ◽  
Yuxiong Xue ◽  
Min Zhou ◽  
Rongxing Cao ◽  
Xianghua Zeng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Low Temperature ◽  
Solder Joint ◽  
Design Methodology ◽  
Solder Joints ◽  
Fracture Morphology ◽  
Content Type ◽  
Before And After ◽  
Mechanical Performances

Purpose The purpose of this paper is to investigate the effects of Sn-Ag-x leveling layers on the mechanical properties of SnBi solder joints. Four Sn-Ag-x (Sn-3.0Ag-0.5Cu, Sn-0.3Ag-0.7Cu, Sn-0.3Ag-0.7Cu-0.5 Bi-0.05Ni and Sn-3.0Ag-3.0 Bi-3.0In) leveling layers were coated on Cu pads to prepare SnBi/Sn-Ag-x/Cu solder joints. The microstructure, hardness, shear strength and fracture morphology of solder joints before and after aging were studied. Design/methodology/approach The interfacial brittleness of the SnBi low-temperature solder joint is a key problem affecting its reliability. The purpose of this study is to improve the mechanical properties of the SnBi solder joint. Findings Owing to the addition of the leveling layers, the grain size of the ß-Sn phase in the SnBi/Sn-Ag-x/Cu solder joint is significantly larger than that in the SnBi/Cu eutectic solder joint. Meanwhile, the hardness of the solder bulk in the SnBi/Cu solder joint shows a decrease trend because of the addition of the leveling layers. The SnBi/Cu solder joint shows obvious strength drop and interfacial brittle fracture after aging. Through the addition of the Sn-Ag-x layers, the brittle failure caused by aging is effectively suppressed. In addition, the Sn-Ag-x leveling layers improve the shear strength of the SnBi/Cu solder joint after aging. Among them, the SnBi/SACBN/Cu solder joint shows the highest shear strength. Originality/value This work suppresses the interfacial brittleness of the SnBi/Cu solder joint after isothermal aging by adding Sn-Ag-x leveling layers on the Cu pads. It provides a way to improve the mechanical performances of the SnBi solder joint.

Effect of Isothermal Aging on the Growth and Morphology of the Intermetallic Compounds Formed at the Solder/Cu Interface of the Lead - Free Solder Joint

2007 ◽  
Vol 561-565 ◽  
pp. 2115-2118
Author(s):  
Yun Fu ◽  
Qi Zhang ◽  
Feng Sun ◽  
Hao Yu Bai
Keyword(s):  
Solder Joint ◽  
Intermetallic Compounds ◽  
Aging Time ◽  
Isothermal Aging ◽  
Lead Free ◽  
Intermetallic Compound Layer ◽  
Lead Free Solder ◽  
Cu Substrate ◽  
Cu6sn5 Layer ◽  
Free Solder

The growth and morphology of the intermetallic compounds (IMC) formed at the interface between the solder ( Sn–3.5Ag–0.5Cu ) and the Cu substrate of the lead - free solder joint have been investigated by means of isothermal aging at 125°C. The scalloped Cu6Sn5 intermetallic compound layer was formed at the interface between the solder and Cu substrate upon reflow. The thickness of Cu6Sn5 layer increased with aging time. Cu3Sn appeared between Cu6Sn5 layer and Cu substrate when isothermally aged for 100 hours. Compare to Cu6Sn5 , the thickness of Cu3Sn was rather low, and nearly did not increase with aging time. In this paper, the comparison was made among the Sn-Pb and the Sn-Ag-Cu(SAC) solders which were pre-treated differently before soldering.

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