Influence of Microstructure Evolution on the Current Density and Temperature Gradient of Line-Type Cu/Sn58Bi/Cu Microscale Solder Joints Under Current Stressing

2022 ◽  
Author(s):  
Hongbo Qin ◽  
Chuyi Lei ◽  
Xinghe Luan ◽  
Quanzhang Wen ◽  
Wangyun Li
Keyword(s):  
Temperature Gradient ◽  
Microstructure Evolution ◽  
Current Density ◽  
Solder Joints ◽  
Current Stressing ◽  
Line Type

Effects of Current Stressing and Isothermal Aging on the Tensile Strength of Microscale Lead-Free Solder Joints with Different Joint Volumes

2013 ◽  
Vol 634-638 ◽  
pp. 2800-2803 ◽  
Author(s):  
Li Meng Yin ◽  
Yan Fei Geng ◽  
Zhang Liang Xu ◽  
Song Wei
Keyword(s):  
Tensile Strength ◽  
Current Density ◽  
Isothermal Aging ◽  
Solder Joints ◽  
High Current Density ◽  
Copper Wire ◽  
Lead Free ◽  
Lead Free Solder ◽  
Current Stressing ◽  
Free Solder

Adopting an accurate micro-tensile method based on dynamic mechanical analyzer (DMA) instrument, the tensile strength of three kinds of copper-wire/solder/copper-wire sandwich structured microscale lead-free solder joints that underwent current stressing with a direct current density of 1.0×104 A/cm2 and loading time of 48 hours were investigated, and compared with those solder joints isothermal aged at 100 0C for 48 hours and as-reflowed condition. These three kinds of microscale columnar solder joints have different volumes, i.e., a same diameter of 300 μm but different heights of 100 μm, 200 μm and 300 μm. Experimental results show that both current stressing and isothermal aging degrades the tensile strength of microscale solder joints, and the solder joint with smaller volume obtains higher tensile strength under same test condition. In addition, current stressing induces obvious electromigration (EM) issue under high current density of 1.0×104 A/cm2, resulting in the decreasing of tensile strength and different fracture position, mode and surface morphology of microscale solder joints. The degree of strength degradation increases with the increasing of joint height when keep joint diameter constant, this is mainly due to that electromigration leads to voids form and grow at the interface of cathode, and solder joints with larger volume may contains more soldering defects as well.

Electromigration Reliability With Respect to Cu Weight Contents of Sn–Ag–Cu Flip-Chip Solder Joints Under Comparatively Low Current Stressing

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Yi-Shao Lai ◽  
Ying-Ta Chiu
Keyword(s):  
Intermetallic Compound ◽  
Ambient Temperature ◽  
Current Density ◽  
Flip Chip ◽  
Solder Joints ◽  
Average Current Density ◽  
Current Stressing ◽  
Weight Content ◽  
Average Current ◽  
Better Than

This work presents electromigration reliability and patterns of Sn–3Ag–0.5Cu and Sn–3Ag–1.5Cu∕Sn–3Ag–0.5Cu composite flip-chip solder joints with Ti∕Ni(V)∕Cu under bump metallurgy (UBM), bonded on Au∕Ni∕Cu substrate pads. The solder joints were subjected to an average current density of 5kA∕cm2 under an ambient temperature of 150°C. Under the situation when electron charges flow from the UBM toward the substrate, Sn diffuses from the Cu–Ni–Sn intermetallic compound developed around the UBM toward the UBM and eventually causes the Ni(V) layer to deform. Electromigration reliability of Sn–3Ag–1.5Cu∕Sn–3Ag–0.5Cu composite flip-chip solder joints was found to be better than that of Sn–3Ag–0.5Cu solder joints. According to the morphological observations on cross-sectioned solder joints, a failure mechanism is proposed as follows. Since the deformation of the Ni(V) layer as a result of Sn diffusion toward the UBM is considered as the dominant failure, a greater Cu weight content in the solder joints would trap more Sn in the Sn–Cu interfacial reaction and would therefore retard the diffusion of Sn toward the UBM and hence enhance the electromigration reliability.

scholarly journals Abnormal Shear Performance of Microscale Ball Grid Array Structure Cu/Sn–3.0Ag–0.5Cu/Cu Solder Joints with Increasing Current Density

Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 85
Author(s):  
Bo Wang ◽  
Wangyun Li ◽  
Kailin Pan
Keyword(s):  
Shear Strength ◽  
Critical Current Density ◽  
Joule Heating ◽  
Current Density ◽  
Solder Joints ◽  
Solder Matrix ◽  
Ball Grid Array ◽  
Current Stressing ◽  
Shear Performance ◽  
Array Structure

The shear performance and fracture behavior of microscale ball grid array structure Cu/Sn–3.0Ag–0.5Cu/Cu solder joints with increasing electric current density (from 1.0 × 103 to 6.0 × 103 A/cm2) at various test temperatures (25 °C, 55 °C, 85 °C, 115 °C, 145 °C, and 175 °C) were investigated systematically. Shear strength increases initially, then decreases with increasing current density at a test temperature of no more than 85 °C; the enhancement effect of current stressing on shear strength decreases and finally diminishes with increasing test temperatures. These changes are mainly due to the counteraction of the athermal effect of current stressing and Joule heating. After decoupling and quantifying the contribution of the athermal effect to the shear strength of solder joints, the results show that the influence of the athermal effect presents a transition from an enhancement state to a deterioration state with increasing current density, and the critical current density for the transition decreases with increasing test temperatures. Joule heating is always in a deterioration state on the shear strength of solder joints, which gradually becomes the dominant factor with increasing test temperatures and current density. In addition, the fracture location changes from the solder matrix to the interface between the solder matrix and the intermetallic compound (IMC) layer (the solder/IMC layer interface) with increasing current density, showing a ductile-to-brittle transition. The interfacial fracture is triggered by current crowding at the groove of the IMC layer and driven by mismatch strain at the solder/IMC layer interface, and the critical current density for the occurrence of interfacial fracture decreases with increasing test temperatures.

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