Interfacial intermetallic compound growth in Sn-3Ag-0.5Cu/Cu solder joints induced by stress gradient at cryogenic temperatures

2019 ◽  
Vol 800 ◽  
pp. 180-190 ◽  
Author(s):  
Ruyu Tian ◽  
Chunjin Hang ◽  
Yanhong Tian ◽  
Bingying Wu ◽  
Yubin Liu ◽  
...  
Keyword(s):  
Intermetallic Compound ◽  
Solder Joints ◽  
Stress Gradient ◽  
Cryogenic Temperatures ◽  
Intermetallic Compound Growth ◽  
Interfacial Intermetallic Compound

Effect of Ni concentration on solderability, microstructure and hardness of SAC0705-xNi solder joints on Cu and graphene-coated Cu substrates

2019 ◽  
Vol 33 (01) ◽  
pp. 1850425 ◽  
Author(s):  
Hongming Cai ◽  
Yang Liu ◽  
Shengli Li ◽  
Hao Zhang ◽  
Fenglian Sun ◽  
...  
Keyword(s):  
Intermetallic Compound ◽  
Diffusion Barrier ◽  
Graphene Layer ◽  
Solder Joints ◽  
Cu Substrate ◽  
Ni Content ◽  
Increasing Trend ◽  
Cu Substrates ◽  
Interfacial Intermetallic Compound ◽  
Positive Effect

In this paper, solderability, microstructure and hardness of SAC0705-xNi solder joints on Cu and graphene-coated Cu (G-Cu) substrates were studied. As Ni content increases in the solder, the solderability improves gradually on both the Cu and G-Cu substrates. The solderability of SAC0705-xNi is better on G-Cu substrate than that on Cu substrate. The increasing Ni content in the solder has a positive effect on the microstructure refinement of both the kinds of substrates. Such effect is more significant on G-Cu substrate than that on Cu substrate. With the increase of Ni content, the thickness of the interfacial intermetallic compound (IMC) shows an increasing trend first and then decreasing trend on the two kinds of substrates. Since the graphene layer works as a diffusion barrier, the IMC on G-Cu is thinner than that on Cu substrate. The addition of Ni leads to the strengthening of the microstructure and thus increases the hardness of the solder bulks.

Effect of Solder Joint Thickness on Intermetallic Compound Growth Rate of Cu/Sn/Cu Solder Joints During Thermal Aging

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Yan Zhu ◽  
Fenglian Sun
Keyword(s):  
Growth Rate ◽  
Intermetallic Compound ◽  
Solder Joint ◽  
Aging Time ◽  
Thermal Aging ◽  
Solder Joints ◽  
Control Element ◽  
Joint Thickness ◽  
Intermetallic Compound Growth ◽  
Peak Value

The sandwich structure Cu/Sn/Cu solder joints with different thicknesses of the solder layers (δ) are fabricated using a reflow solder method. The microstructure and composition of the solder joints are observed and analyzed by scanning electron microscopy (SEM). Results show that the thickness of intermetallic compound (IMC) and Cu concentration in the solder layers increase with the decrease of δ after reflow. During thermal aging, the thickness of IMC does not increase according to the parabolic rule with the increase of aging time; the solder joint thickness affects markedly the growth rate of IMC layer. At the beginning of thermal aging, the growth rate of IMC in the thinner solder joints (δ ≤ 25 μm) is higher than that in the thicker ones (δ ≥ 30 μm). The growth rate of IMC (δ ≤ 25 μm) decreases in the thinner solder joints, while increases in the thicker solder joints (δ ≥ 40 μm) and is nearly invariable when the δ equals to 30 μm with aging time extending. The growth rate of IMC increases first and then decreases after reaching a peak value with the increase of δ in the later stage during aging. The main control element for IMC growth transfers from Cu to Sn with the reduction of size.

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