Impact of thermal aging on the intermetallic compound particle size and mechanical properties of lead free solder for green electronics

Abstract The Sn-Ag3.0-Cu0.5 lead free solder (LFS) alloy is mostly used as good alternative as compared to conventional Tin-Lead (Sn-Pb) due to its good mechanical properties and no harmful effect on environment but it stills has some problems to be solved regarding the growth formation of intermetallic compounds (IMCs). The IMCs present inside the bulk tin (Sn) matrix grow at high temperature and hence their impact on mechanical properties becomes more significant. In this work the effects of lanthanum (La) doping of Sn-Ag3.0-Cu0.5 is investigated as function of IMCs growth and mechanical properties including yield strength (YS) and ultimate tensile strength (UTS) under different thermal aging temperatures. The selected La concentration in this study is 0.4 wt%. The aging time is 50 h and thermal aging temperatures are 60 °C, 100 °C and 140 °C. The microstructure examination before and after thermal aging is observed using scanning electron microscopy (SEM) followed by image analysis to estimate the nature of IMCs. The chemical composition is confirmed with energy dispersive X-ray (EDX). The YS and UTS are also examined before and after thermal aging for the un-doped and doped samples from stress-strain curves using universal testing machine (UTM). It is investigated that inclusion of 0.4 wt% La into Sn-Ag3.0-Cu0.5 solder system results in increasing the IMCs growth rate and hence mechanical properties reduced. It is also observed that the microstructure becomes coarsen after thermal aging due to growth of average IMCs particle size with significant decrease in YS and UTS. Further, mathematical relations with minimum error are developed to predict mechanical properties (YS and UTS) at various levels of aging temperature, showing a reciprocal relationship between aging temperature and mechanical properties.

[1]  Wei Zhou,et al.  Effects of Ni-coated carbon nanotubes addition on the microstructure and mechanical properties of Sn–Ag–Cu solder alloys , 2014 .

[2]  M. Abtew,et al.  Lead-free Solders in Microelectronics , 2000 .

[3]  Z. Xia,et al.  Study on the microstructure of a novel lead-free solder alloy SnAgCu-RE and its soldered joints , 2002 .

[4]  M. Cherkaoui,et al.  Impact of Thermal Aging on the Microstructure Evolution and Mechanical Properties of Lanthanum-Doped Tin-Silver-Copper Lead-Free Solders , 2013, Journal of Electronic Materials.

[5]  G. Li,et al.  Influence of Sb on IMC growth in Sn–Ag–Cu–Sb Pb-free solder joints in reflow process , 2004 .

[6]  A. Kokabi,et al.  Ceria reinforced nanocomposite solder foils fabricated by accumulative roll bonding process , 2012, Journal of Materials Science: Materials in Electronics.

[7]  Mohd Rafie Johan,et al.  Addition of cobalt nanoparticles into Sn-3.8Ag-0.7Cu lead-free solder by paste mixing , 2011 .

[8]  Y. Chan,et al.  Microstructures and properties of new Sn–Ag–Cu lead-free solder reinforced with Ni-coated graphene nanosheets , 2016 .

[9]  S. Xue,et al.  Review Article: Effect of alloying elements on properties and microstructures of SnAgCu solders , 2010 .

[10]  L. Tsao,et al.  Effects of small amount of active Ti element additions on microstructure and property of Sn3.5Ag0.5Cu solder , 2012 .

[11]  F. Che,et al.  Microstructural stability of Sn–1Ag–0.5Cu–xAl (x = 1, 1.5, and 2 wt.%) solder alloys and the effects of high-temperature aging on their mechanical properties , 2013 .

[12]  S. Xue,et al.  Microstructure and creep properties of Sn-Ag-Cu lead-free solders bearing minor amounts of the rare earth cerium , 2010 .

[13]  Chi‐Man Lawrence Wu,et al.  Properties of lead-free solder alloys with rare earth element additions , 2004 .

[14]  V. Kripesh,et al.  Single-wall carbon nanotube (SWCNT) functionalized Sn–Ag–Cu lead-free composite solders , 2008 .

[15]  Y. C. Chan,et al.  The influence of addition of Al nano-particles on the microstructure and shear strength of eutectic Sn-Ag-Cu solder on Au/Ni metallized Cu pads , 2010 .

[16]  A. E. Hammad.  Evolution of microstructure, thermal and creep properties of Ni-doped Sn–0.5Ag–0.7Cu low-Ag solder alloys for electronic applications , 2013 .

[17]  Jamaluddin Abdullah,et al.  Effect of iron and indium on IMC formation and mechanical properties of lead-free solder , 2012 .

[18]  Fa Xing Che,et al.  Material Characterization and Low Cycle Fatigue Model of Low Ag Content Lead-Free Solder , 2017, IEEE Transactions on Device and Materials Reliability.

[19]  J. Qu,et al.  Effect of Lanthanum Doping on the Microstructure of Tin-Silver Solder Alloys , 2008 .

[20]  Chris Bailey,et al.  Effect of adding 1 wt% Bi into the Sn–2.8Ag–0.5Cu solder alloy on the intermetallic formations with Cu-substrate during soldering and isothermal aging , 2006 .

[21]  K. Tu,et al.  Six cases of reliability study of Pb-free solder joints in electronic packaging technology , 2002 .

[22]  Liang Zhang,et al.  Microstructures and properties of SnZn-xEr lead-free solders , 2012 .

[23]  H. Jing,et al.  Effect of graphene nanosheets reinforcement on the performance of SnAgCu lead-free solder , 2013 .

[24]  Fu Guo,et al.  Effects of small amount addition of rare earth Er on microstructure and property of SnAgCu solder , 2008 .

[25]  Jianmin Qu,et al.  Creep and Fatigue Behavior of SnAg Solders With Lanthanum Doping , 2008, IEEE Transactions on Components and Packaging Technologies.

[26]  Daniel Lewis,et al.  Microstructural evolution in lead-free solder alloys: Part II. Directionally solidified Sn-Ag-Cu, Sn-Cu and Sn-Ag , 2004 .

[27]  Tadashi Ariga,et al.  Wettability and strength of In–Bi–Sn lead-free solder alloy on copper substrate , 2010 .

[28]  A. E. Hammad,et al.  Influence of Zn addition on the microstructure, melt properties and creep behavior of low Ag-content Sn–Ag–Cu lead-free solders , 2014 .

[29]  S. Xue,et al.  Effects of Ga addition on microstructure and properties of Sn–0.5Ag–0.7Cu solder , 2014, Journal of Materials Science: Materials in Electronics.

[30]  Rong-Sheng Chen,et al.  Effects of nano-Al2O3 particles on microstructure and mechanical properties of Sn3.5Ag0.5Cu composite solder ball grid array joints on Sn/Cu pads , 2013 .

[31]  Li-Wei Lin,et al.  Alloying modification of Sn-Ag-Cu solders by manganese and titanium , 2009, Microelectron. Reliab..

[32]  Katsuaki Suganuma,et al.  Effects of intermetallic compounds on properties of Sn–Ag–Cu lead-free soldered joints , 2003 .

[33]  Yu Tang,et al.  Effects of TiO2 nanoparticles addition on microstructure, microhardness and tensile properties of Sn–3.0Ag–0.5Cu–xTiO2 composite solder , 2014 .

[34]  Yongchang Liu,et al.  Effects of aging on microstructure evolution and mechanical properties of high-temperature Zn-4Al-3Mg solder , 2014 .

[35]  R. Vinci,et al.  Microstructural evolution in lead-free solder alloys: Part I. Cast Sn–Ag–Cu eutectic , 2004 .

[36]  Bakhtiar Ali.  Advancement in microstructure and mechanical properties of lanthanum-doped tin-silver-copper lead free solders by optimizing the lanthanum doping concentration , 2015 .

[37]  Thermomechanical fatigue of solder joints: a new comprehensive test method , 1989 .

[38]  T. Ariga,et al.  Influences of Aging Treatment on Microstructure and Hardness of Sn-(Ag, Bi, Zn) Eutectic Solder Alloys , 2001 .

[39]  S. Xue,et al.  Microstructure characterization of SnAgCu solder bearing Ce for electronic packaging , 2011 .

[40]  X. Shi,et al.  Effects of Sb addition on tensile strength of Sn-3.5Ag-0.7Cu solder alloy and joint , 2006 .

[41]  Periannan Arulvanan,et al.  Effects of process conditions on reliability, microstructure evolution and failure modes of SnAgCu solder joints , 2006, Microelectron. Reliab..

[42]  James Marrow,et al.  3D Studies of Indentation by Combined X-Ray Tomography and Digital Volume Correlation , 2013 .

[43]  M. Mccormack,et al.  Improved mechanical properties in new, Pb-free solder alloys , 1994 .