Study on Subgrain Rotation Behavior at Different Interfaces of a Solder Joint During Thermal Shock

In order to investigate subgrain rotation behavior in the recrystallized region of lead-free solder joints, a ball grid array (BGA) specimen with a cross-sectioned edge row was thermally shocked. Electron backscattered diffraction (EBSD) was used to obtain the microstructure and orientations of Sn grains or subgrains in as-reflowed and thermally shocked conditions. Orientation imaging microscopy (OIM) showed that several subgrains were formed at the tilted twin grain boundaries, near the chip side and near the printed circuit board (PCB) side after 200 thermal shocks due to a highly mismatched coefficient of thermal expansion (CTE) of twin grains. Also, subgrains formed at the chip side and PCB side in the solder joint were selected to research the grain rotation behavior in lead-free solder joints. The analysis of subgrain rotation also indicated that the rotation behavior of subgrains was different between the chip side and PCB side. It was closely related with the large different crystal orientations between the chip side and PCB side. Furthermore, electron backscattered patterns (EBSPs) at several parts of the joint were not obtained after 300 thermal shocks due to the serious deformation caused by mismatched CTE during thermal shock. But 4 subgrains were selected and compared with that of the initial state and 200-thermal shock conditions. The results showed that the subgrains at the chip side were also rotated around the Sn [101] and [001] axes and the subgrains at the PCB side were also rotated around the Sn [100] axis, which indicated a continuous process of subgrain rotation.

[1]  L. H. Hsu,et al.  Influence of Pd Concentration on the Interfacial Reaction and Mechanical Reliability of the Ni/Sn-Ag-Cu-xPd System , 2011, Journal of Electronic Materials.

[2]  T. Bieler,et al.  Methodology for Analyzing Strain States During In Situ Thermomechanical Cycling in Individual Lead-Free Solder Joints Using Synchrotron Radiation , 2009 .

[3]  Ning Zhao,et al.  In situ study on the effect of thermomigration on intermetallic compounds growth in liquid-solid interfacial reaction , 2014 .

[4]  Ke Wu,et al.  Millimeter-Wave Broadband Transition of Substrate Integrated Waveguide on High-to-Low Dielectric Constant Substrates , 2012, IEEE Transactions on Components, Packaging and Manufacturing Technology.

[5]  R. Słomski,et al.  Biomechanical properties of hybrid heart valve prosthesis utilizing the pigs that do not express the galactose-α-1,3-galactose (α-Gal) antigen derived tissue and tissue engineering technique , 2015, Journal of Materials Science: Materials in Medicine.

[6]  Yi-Shao Lai,et al.  Recent research advances in Pb-free solders , 2009, Microelectron. Reliab..

[7]  Thomas R. Bieler,et al.  Slip, Crystal Orientation, and Damage Evolution During Thermal Cycling in High-Strain Wafer-Level Chip-Scale Packages , 2015, Journal of Electronic Materials.

[8]  Peter Borgesen,et al.  Effects of latent damage of recrystallization on lead free solder joints , 2014, Microelectron. Reliab..

[9]  Jussi Hokka,et al.  The Reliability of Microalloyed Sn-Ag-Cu Solder Interconnections Under Cyclic Thermal and Mechanical Shock Loading , 2014, Journal of Electronic Materials.

[10]  M. Geers,et al.  Thermomechanical fatigue damage evolution in SAC solder joints , 2007 .

[11]  Katsuaki Suganuma,et al.  Mitigation of Sn Whisker Growth by Small Bi Additions , 2013, Journal of Electronic Materials.

[12]  T. Bieler,et al.  Characterization of Recrystallization and Microstructure Evolution in Lead-Free Solder Joints Using EBSD and 3D-XRD , 2013, Journal of Electronic Materials.

[13]  K. N. Subramanian,et al.  Grain-boundary character and grain growth in bulk tin and bulk lead-free solder alloys , 2004 .

[14]  Thomas R. Bieler,et al.  Methodology for Analyzing Slip Behavior in Ball Grid Array Lead-Free Solder Joints After Simple Shear , 2009 .

[15]  Pradeep Lall,et al.  Stress–Strain Behavior of SAC305 at High Strain Rates , 2015 .

[16]  N. Tamura,et al.  In situ synchrotron study of electromigration induced grain rotations in Sn solder joints , 2016, Scientific Reports.

[17]  Thomas R. Bieler,et al.  Influence of High-G Mechanical Shock and Thermal Cycling on Localized Recrystallization in Sn-Ag-Cu Solder Interconnects , 2013, Journal of Electronic Materials.

[18]  Mali Zhao,et al.  Fracture Behaviors of Sn-Cu Intermetallic Compound Layer in Ball Grid Array Induced by Thermal Shock , 2014, Journal of Electronic Materials.

[19]  Masako Nozaki,et al.  Recrystallization of Sn Grains due to Thermal Strain in Sn-1.2Ag-0.5Cu-0.05Ni Solder , 2004 .