Papers by Keyword: Ball Shear Test

Abstract: Both experimental and numerical analyses into the shear toughness parameter for Sn/3.0Ag/0.5Cu and 63Sn/37Pb solder ball joints are performed. The ball shear tests are conducted at the loading speeds of 200μm/s and 300μm/s using ball joint specimens with diameters of 300, 600 and 760 μm. The failure behavior of the solder joints is quantified in terms of their fracture toughness. The results show that the shear toughness increases with an increasing solder ball diameter. Furthermore, it is shown that the Sn/3.0Ag/0.5Cu solder ball has a greater ductility than the eutectic 63Sn/37Pb solder ball. It is found that the shear toughness with great differentiability is relatively insensitive to the loading speed, and is therefore a suitable parameter with which to evaluate the ductility of solder ball joints in ball shear tests. Finally, the finite element analysis is further employed in the simulation with the software of MSC, Marc. Numerical predictions have good agreements compared with experiment ones.

Abstract: The interfacial reactions and shear properties of Sn-37Pb (wt.%) solder bumps with two different under bump metallizations (UBMs), Cu and Ni, were investigated after high temperature storage (HTS) tests at 150
C for up to 65 days. Two different intermetallic compounds (IMCs), Cu6Sn5 and Cu3Sn, were formed at the bump/Cu interface, whereas only a Ni3Sn4 IMC layer was formed at the bump/Ni interface. The thicknesses of these IMCs increased linearly with the square root of duration time. The IMC growth rate at the bump/Cu UBM interface was much greater than that at the bump/Ni UBM interface. The shear properties of the bumps with the Cu UBM were greatly decreased with increasing duration time, compared with those with the Ni UBM.

Abstract: The interfacial reactions and bump shear properties of the electroplated Sn-37Pb (in wt.%) solder bumps with the Ni under bump metallization (UBM) were investigated as a function of the number of reflows. A continuous facetted Ni3Sn4 intermetallic compound (IMC) layer was formed at the interface between the solder bump and the Ni UBM during reflow. The thickness of the Ni3Sn4 IMC layer was 0.41 μm after 1 reflow, and then the thickness of the IMC layer increased with increasing the number of reflows. The shear properties of the bumps indicated the maximum values after 1 reflow, and then decreased with increasing the number of reflows. The fracture surfaces of the bumps showed ductile failure characteristics after 1 reflow, and then the fraction of the brittle fracture, induced by the IMC formed at the interface, increased with increasing the number of reflows.

Abstract: The mechanical and electrical properties of the Sn-3.5Ag solder/Cu BGA packages were investigated as a function of number of reflows. A continuous scallop-shaped Cu6Sn5 intermetallic compound (IMC) layer was formed at the solder/Cu interface upon 1 reflow process. After 3 reflows, very thin layer of Cu3Sn IMC was observed at the Cu6Sn5/Cu interface. As the number of reflows increased, the thickness of these IMCs increased with a cube root of reflow time. Shear force slightly increased up to 4 reflows and then gradually decreased with increasing the number of reflows. The maximum shear force was 11.7N when the thickness of the IMC layers was 3.7㎛. The fracture surfaces of all the specimens showed ductile failure characteristics up to 4 reflows, and then the fraction of the brittle IMC fracture increased with the number of reflows. The electrical resistance of the BGA packages increased with the number of reflows.