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.

Effects of Fe on the Kirkendall Void Formation of Sn-3.5Ag-xFe/Cu Solder Joints

2010 ◽  
Vol 2010 (1) ◽  
pp. 000294-000297 ◽  
Author(s):  
S. H. Kim ◽  
Jin Yu
Keyword(s):  
Solder Joint ◽  
Solder Joints ◽  
Void Formation ◽  
Kirkendall Void ◽  
Fe Content ◽  
Kirkendall Voids

Ternary Sn-3.5Ag-xFe solders with varying amount of Fe; 0.1, 0.5, 1.0, and 2.0 wt. % were reacted with Cu UBM which was electroplated using SPS additive and characteristics of Kirkendall void formation at the solder joints were investigated. Results indicate that the propensity to form Kirkendall voids at the solder joint decreased with the Fe content. It showed that Fe dissolved in the Cu UBM and reduced the segregation of S atoms to the Cu3Sn/Cu interface, which suppressed the nucleation of Kirkendall voids at the interface.

Reinforced Solder Technology for Increased Reliability

2017 ◽  
Vol 2017 (1) ◽  
pp. 000641-000645
Author(s):  
Tim Jensen ◽  
Sunny Neoh ◽  
Adam Murling
Keyword(s):  
Melting Point ◽  
Solder Joint ◽  
Solder Joints ◽  
Reliability Of Solder Joints ◽  
Impact Reliability ◽  
Selection Of

Abstract The reliability of solder joints have been studied for many years. The selection of a solder for a particular application is often limited based on melting point requirements. This limits the number of options that are available for use. When alloy selection options are limited, people look to process changes to try and improve the reliability. Two such areas that have been identified that can impact reliability are bondline control and void reduction. This paper analyzes a new reinforced solder technology to maintain a consistent solder joint bondline. Experiments were also conducted to determine how best to design these preforms to minimize voiding.

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).

Growth behavior of Cu/Al intermetallic compounds and cracks in copper ball bonds during isothermal aging

2008 ◽  
Vol 48 (3) ◽  
pp. 416-424 ◽  
Author(s):  
C.J. Hang ◽  
C.Q. Wang ◽  
M. Mayer ◽  
Y.H. Tian ◽  
Y. Zhou ◽  
...  
Keyword(s):  
Intermetallic Compounds ◽  
Isothermal Aging ◽  
Growth Behavior ◽  
Ball Bonds

Nanoindentation Measurements of the Mechanical Properties of Individual Phases Within Lead Free Solder Joints Subjected to Isothermal Aging

2018 ◽  
Author(s):  
Abdullah Fahim ◽  
Sudan Ahmed ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
Mechanical Properties ◽  
Isothermal Aging ◽  
Solder Joints ◽  
Bulk Solder ◽  
Lead Free ◽  
Nanoindentation Test ◽  
Lead Free Solder ◽  
Free Solder ◽  
The Individual ◽  
Sac Solder

Exposure of lead free solder joints to high temperature isothermal aging conditions leads to microstructure evolution, which mainly includes coarsening of the intermetallic (IMC) phases. In our previous work, it was found that the coarsening of IMCs led to degradation of the overall mechanical properties of the SAC solder composite consisting of β-Sn matrix and IMC particles. However, it is not known whether the isothermal aging changes properties of the individual β-Sn and IMC phases, which could also be affecting to the overall degradation of properties. In this study, the aging induced variations of the mechanical properties of the β-Sn phase, and of Sn-Cu IMC particles in SAC solder joints have been explored using nanoindentation. SAC solder joints extracted from SuperBGA (SBGA) packages were aged for different time intervals (0, 1, 5, 10 days) at T = 125 °C. Nanoindentation test samples were prepared by cross sectioning the solder joints, and then molding them in epoxy and polishing them to prepare the joint surfaces for nanoindentation. Multiple β-Sn grains were identified in joints using optical polarized microscopy and IMCs were also observed. Individual β-Sn grains and IMC particles were then indented at room temperature to measure their mechanical properties (elastic modulus and hardness) and time dependent creep deformations. Properties measured at different aging time were then compared to explore aging induced degradations of the individual phases. The properties of the individual phases did not show significant degradation. Thus, IMC coarsening is the primary reason for the degradation of bulk solder joint properties, and changes of the properties of the individual phases making up the lead free solder material are negligible.

Isothermal Aging Effects on the Microstructure, IMC and Strength of SnAgCu/Cu Solder Joint

2007 ◽  
Vol 353-358 ◽  
pp. 2928-2931 ◽  
Author(s):  
Xiao Yan Li ◽  
Xiao Hua Yang ◽  
Wei Zhen Dui ◽  
Ben Sheng Wu
Keyword(s):  
Tensile Strength ◽  
Solder Joint ◽  
Aging Time ◽  
Isothermal Aging ◽  
Solder Matrix ◽  
Aging Effects ◽  
Imcs Layer ◽  
X Ray ◽  
Formation And Evolution ◽  
Free Solder

The formation and evolution of the intermetallic compound (IMCs) between SnAgCu lead-free solder and Cu substrate, after isothermal aging at 150°C for 24, 48, 120, 240 and 480 hours, were studied. Scanning electron microscope (SEM) was used to observe the microstructure evolution of solder joint during aging. The IMC phases were identified by energy dispersive X-ray (EDX). The results showed that IMCs layer of Cu6Sn5 was formed at the interface of solder and Cu during reflowing. With the increase of aging time, the grain size of the interfacial Cu6Sn5 increased and the morphology of the interfacial Cu6Sn5 column was changed from scallop-like to needle-like and then to rod-like and finally to particles. At the same time, the rod-like Ag3Sn phase formed at the interface of solder and the IMCs layer of Cu6Sn5 with the aging time increased. In addition, large Cu6Sn5 formed in the solder with the aging time increased. The tensile strength was measured for the solder joints. The results showed that the tensile strength increases slightly at beginning and then decreases with the aging time. SEM was used to observe the fracture surface and it showed that the fracture position moved from solder matrix to the interfacial Cu6Sn5 IMCs layer with the aging time increased. The weakening of the solder matrix is caused by the coarsening of the eutectic solder structures. The weakening of the interfacial IMCs layer is caused by the evolution of morphology and size of the interface Cu6Sn5 layer.

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