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).

Electromigration of Electroplated Gold Interconnects

2005 ◽  
Vol 863 ◽  
Author(s):  
Steve Kilgore ◽  
Craig Gaw ◽  
Haldane Henry ◽  
Darrell Hill ◽  
Dieter Schroder
Keyword(s):  
Activation Energy ◽  
Diffusion Mechanism ◽  
Time To Failure ◽  
Ambient Temperatures ◽  
Temperature Coefficients ◽  
Current Stressing ◽  
Monitoring Technique ◽  
The Times ◽  
A Current

AbstractElectromigration tests were performed on passivated electroplated Au four terminal Kelvin line structures using the conventional in situ resistance monitoring technique. The stress conditions were a current density of 2.0 MA/cm2 with ambient temperatures ranging from 325°C to 375°C. The temperature coefficients of resistance (TCR) values were measured prior to current stressing to calculate the Joule heated film temperatures. The times to failure (lifetimes) for the Au line structures were considered as a 50% ΔR/R0 change. The median time to failure (t50%) was plotted against the inverse film temperature to determine the activation energy value as 0.59 ± 0.09 eV. Failure analysis of void location and suggested diffusion mechanism will be discussed.

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.

scholarly journals Formation Mechanism of Porous Cu3Sn Intermetallic Compounds by High Current Stressing at High Temperatures in Low-Bump-Height Solder Joints

Crystals ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 12 ◽  
Author(s):  
Jie-An Lin ◽  
Chung-Kuang Lin ◽  
Chen-Min Liu ◽  
Yi-Sa Huang ◽  
Chih Chen ◽  
...  
Keyword(s):  
Intermetallic Compounds ◽  
High Temperatures ◽  
Formation Mechanism ◽  
Solder Joints ◽  
High Current ◽  
Bump Height ◽  
Current Stressing

Performance of 96.5Sn–3Ag–0.5Cu/fullerene composite solder under isothermal ageing and high-current stressing

2020 ◽  
Vol 33 (1) ◽  
pp. 35-46 ◽  
Author(s):  
Guang Chen ◽  
Xinzhan Cui ◽  
Yaofeng Wu ◽  
Wei Li ◽  
Fengshun Wu
Keyword(s):  
Solder Joint ◽  
Composite Solder ◽  
Solder Joints ◽  
Experimental Results ◽  
High Current ◽  
Sac305 Solder ◽  
Content Type ◽  
Interfacial Imcs ◽  
Current Stressing ◽  
Isothermal Ageing

Purpose The purpose of this paper is to investigate the effect of fullerene (FNS) reinforcements on the microstructure and mechanical properties of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder joints under isothermal ageing and electrical-migration (EM) stressing. Design/methodology/approach In this paper, SAC305 solder alloy doped with 0.1 Wt.% FNS was prepared via the powder metallurgy method. A sandwich-like sample and a U-shaped sample were designed and prepared to conduct an isothermal ageing test and an EM test. The isothermal ageing test was implemented under vacuum atmosphere at 150°C, whereas the EM experiment was carried out with a current density of 1.5 × 104 A/cm2. The microstructural and mechanical evolutions of both plain and composite solder joints after thermal ageing and EM stressing were comparatively studied. Findings A growth of Ag3Sn intermetallic compounds (IMCs) in solder matrix and Cu-Sn interfacial IMCs in composite solder joints was notably suppressed under isothermal ageing condition, whereas the hardness and shear strength of composite solder joints significantly outperformed those of non-reinforced solder joints throughout the ageing period. The EM experimental results showed that for the SAC305 solder, the interfacial IMCs formulated a protrusion at the anode after 360 h of EM stressing, whereas the surface of the composite solder joint was relatively smooth. During the stressing period, the interfacial IMC on the anode side of the plain SAC305 solder showed a continuous increasing trend, whereas the IMC at the cathode presented a decreasing trend for its thickness as the stressing time increased; after 360 h of stressing, some cracks and voids had formed on the cathode side. For the SAC305/FNS composite solder, a continuous increase in the thickness of the interfacial IMC was found on both the anode and cathode sides; the growth rate of the interfacial IMC at the anode was higher than that at the cathode. The nanoindentation results showed that the hardness of the SAC305 solder joint presented a gradient distribution after EM stressing, whereas the hardness data showed a relatively homogeneous distribution in the SAC305/FNS solder joint. Originality/value The experimental results showed that the FNS reinforcement could effectively mitigate the failure risk in solder joints under isothermal ageing and high-current stressing. Specifically, the FNS particles in solder joints can work as a barrier to suppress the diffusion and migration of Sn and Cu atoms. In addition, the nanoidentation results also indicated that the addition of the FNS reinforcement was very helpful in maintaining the mechanical stability of the solder joint. These findings have provided a theoretical and experimental basis for the practical application of this novel composite solder with high-current densities.

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.

The study on reliability of Ni-coated graphene doped SAC305 lead-free composite solders under high current-density stressing

2019 ◽  
Vol 31 (4) ◽  
pp. 261-270
Author(s):  
Guang Chen ◽  
Jiqiang Li ◽  
Xinwen Kuang ◽  
Yaofeng Wu ◽  
Fengshun Wu
Keyword(s):  
Solder Joint ◽  
Current Density ◽  
Composite Solder ◽  
Solder Joints ◽  
Experimental Results ◽  
Lead Free ◽  
Cathode Side ◽  
High Current ◽  
Sac305 Solder ◽  
Content Type

Purpose The purpose of this paper is to investigate the effect of nickel-plated graphene (Ni-GNS) on the microstructure and mechanical properties of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder joints before and after an electro-migration (EM) experiment. Design/methodology/approach In this paper, SAC305 solder alloy doped with 0.1 Wt.% Ni-GNS was prepared via the powder metallurgy method. A U-shaped sample structure was also designed and prepared to conduct an EM experiment. The EM experiment was carried out with a current density of 1.5 × 104 A/cm2. The microstructural and mechanical evolutions of both solder joints under EM stressing were comparatively studied using SEM and nanoindentation. Findings The experimental results showed that for the SAC305 solder, the interfacial intermetallic compounds (IMC) formulated a protrusion with an average height of 0.42 µm at the anode after 360 h of EM stressing; however, despite this, the surface of the composite solder joint was relatively smooth. During the stressing period, the interfacial IMC on the anode side of the plain SAC305 solder showed a continuous increasing trend, while the IMC at the cathode presented a decreasing trend for its thickness as the stressing time increased; after 360 h of stressing, some cracks and voids had formed on the cathode side. For the SAC305/ Ni-GNS composite solder, a continuous increase in the thickness of the interfacial IMC was found on both the anode and cathode side; the growth rate of the interfacial IMC at the anode was higher than that at the cathode. The nanoindentation results showed that the hardness of the SAC305 solder joint presented a gradient distribution after EM stressing, while the hardness data showed a relatively homogeneous distribution in the SAC305/ Ni-GNS solder joint. Originality/value The experimental results showed that the Ni-GNS reinforcement could effectively mitigate the EM behavior in solder joints under high current stressing. Specifically, the Ni particles that plated the graphene sheets can work as a fixing agent to suppress the diffusion and migration of Sn and Cu atoms by forming Sn-Cu-Ni IMC. In addition, the nanoidentation results also indicated that the addition of the Ni-GNS reinforcement was very helpful in maintaining the mechanical stability of the solder joint. These findings have provided a theoretical and experimental basis for the practical application of this novel composite solder with high current densities.

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.

Electromigration Behavior of Sn58Bi and Sn58Bi Epoxy Solder Joint

2020 ◽  
Vol 12 (4) ◽  
pp. 538-543
Author(s):  
Choong-Jae Lee ◽  
Jae-Ha Kim ◽  
Haksan Jeong ◽  
Jae-Oh Bang ◽  
Seung-Boo Jung
Keyword(s):  
Solder Joint ◽  
High Performance ◽  
Flip Chip ◽  
Solder Joints ◽  
Inorganic Materials ◽  
Constant Current ◽  
Cathode Side ◽  
Test Kit ◽  
Epoxy Solder ◽  
A Current

As demanding for high performance and miniaturization of electronic devices, interconnection materials required higher reliability in mechanical, thermal and electrical. The importance of electromigration issue has increased because of these trends. We evaluated the electromigration behavior of Sn58Bi solder and Sn58Bi epoxy solder under high temperature and constant current flow. The electromigration test-kit was a designed and fabricated flip chip-type module and the diameter of the solder bump was 250 μm. A current was passed through the two solder joints, producing a current density of 3.0 × 103 A/cm2 at 100 °C. The microstructure of solder joint after electromigration test were investigated with field-emission scanning electron microscopy during electromigration, a Bi-rich layer was observed at the anode side of the solder joint and the formation of Kirkendall voids was observed at the cathode side of the solder joints. Different inorganic materials affect electromigration in the eutectic Sn58Bi solder joints.

Electromigration in Copper-Core Solder Ball Joints During Thermal Cycle Tests

2011 ◽  
Author(s):  
Shinichi Fujiwara ◽  
Nobuhiko Chiwata ◽  
Masaru Fujiyoshi ◽  
Motoki Wakano ◽  
Hisashi Tanie
Keyword(s):  
Intermetallic Compounds ◽  
Cross Sections ◽  
Current Density ◽  
Thermal Cycle ◽  
Solder Joints ◽  
Test Sample ◽  
Cathode Side ◽  
Solder Balls ◽  
Current Densities ◽  
Semiconductor Packages

Electromigration current densities in Cu and Al lines on a silicon die exceed 1.0 × 106 A/cm2. However, solder joints can only withstand electromigration current densities below about 1.0 × 104 A/cm2. Thus, electromigration in solder joints will become a problem in semiconductor packages in the near future. Previous studies demonstrated that Cu-core solder balls increased the electromigration lifetime and led to better current stability at temperatures below 423K. This is because electrons flow through the Cu cores, reducing the current density on the cathode side, which is where electromigration occurs. In the present study, we forcused on the reliability of solder joints in a combined environment by examining the effect of thermal cycle tests on the current in a new test sample. A new test sample for the evaluation of joining reliability by using Cu-core solder balls in a combined enbironment was made. In initial tests, this test sample exhibited similar results to those observed in previous studies. Cu-core solder balls subjected to cyclic testing at 233/398K and a current density of 1.0 × 104 A/cm2 exhibited lower reliabilities than when there was no current. Examination of cross-sections of the solder balls after reliability testing revealed that the combined environment accelerated growth of intermetallic compounds and cracks in the joining region. In a combined environment, Cu-core balls were converted into intermetallic compounds on the anode side. This phenomenon is thought to occur due to the different electrical resistivities of Cu-Sn intermetallic compounds.

Sign in / Sign up

Export Citation Format

Share Document