MICROSTRUCTURE AND INTERFACIAL INTERMETALLIC OF Sn-3.0Ag-0.5Cu/Sn-58Bi SOLDER JOINT FOR PACKAGE-ON-PACKAGE TECHNOLOGY

In this study, the effect of growth microstructure on diffusion and intermetallic compound of Sn-58Bi/SAC305 solder joint with different of SAC305 size and reflow temperature had been studied. For effect of different size, it used 180°C reflow temperature and 5minute reflow time with the size of SAC305 solder ball was 800μm, 900μm and 1000μm. For the reflow temperature would reflow at 160°C,170°C, 180°C, and 190°C for 5minute reflow time. After the reflow process, a sample would go through a several processes such as molding, grinding and polishing before undergoing material characterization. The diffusion area had shown an inversely relationship with SAC305 size and linearly relationship with temperature and time reflow. Besides, the IMC thickness was thinner with increasing of SAC305 size. In this finding, the area of Sn-58Bi/SAC305 solder joint could be predicted to enhance the package on package technology

Influence of 1.5 wt.% Bi on the Microstructure, Hardness, and Shear Strength of Sn-0.7Cu Solder Joints after Isothermal Annealing

This manuscript reports the isothermal annealing effect on the mechanical and microstructure characteristics of Sn-0.7Cu-1.5Bi solder joints. A detailed microstructure observation was carried out, including measuring the activation energy of the intermetallic compound (IMC) layer of the solder joints. Additionally, the synchrotron µX-ray fluorescence (XRF) method was adopted to precisely explore the elemental distribution in the joints. Results indicated that the Cu6Sn5 and Cu3Sn intermetallic layers thickness at the solder/Cu interface rises with annealing time at a rate of 0.042 µm/h for Sn-0.7Cu and 0.037 µm/h for Sn-0.7Cu-1.5Bi. The IMC growth’s activation energy during annealing is 48.96 kJ mol-1 for Sn-0.7Cu, while adding Bi into Sn-0.7Cu solder increased the activation energy to 55.76 kJ mol−1. The µ-XRF shows a lower Cu concentration level in Sn-0.7Cu-1.5Bi, where the Bi element was well dispersed in the β-Sn area as a result of the solid solution mechanism. The shape of the IMC layer also reconstructs from a scallop shape to a planar shape after the annealing process. The Sn-0.7Cu hardness and shear strength increased significantly with 1.5 wt.% Bi addition in reflowed and after isothermal annealing conditions

EFFECT OF BISMUTH CONTENT ON MICROSTRUCTURE, MELTING TEMPERATURE AND UNDERCOOLING OF SN-0.7CU SOLDER ALLOY

The aim of this manuscript to study the influence of Bismuth (Bi) addition on the microstructure, melting temperature and undercooling of Sn-0.7Cu solder alloys. In this study, several Bi composition were chosen which is 0 wt.%, 0.25 wt.%, 0.5 wt.%, 1.0 wt.% and 2.0 wt%. The result indicated that with addition of Bi element, it can refine the β-Sn and reduce the size of primary Cu6Sn5. The melting temperature of Sn-0.7Cu solder alloy was observed by DSC result and found there is no significant changes of melting temperature by Bi additions. However, with Bi addition, it will reduce the undercooling of the Sn-0.7Cu solder alloys

Effect of bismuth additions on wettability, intermetallic compound, and microhardness properties of Sn-0.7Cu on different surface finish substrates

The influence of bismuth (Bi) addition on wettability, thickness of interfacial intermetallic compound (IMC), and microhardness properties of Sn-0.7Cu + xBi solder alloy using different types of substrate were examined. The 0.5, 1.0, 1.5, and 2.0 wt. % Bi was added into Sn-0.7Cu and fabricated using the casting process. The result shows that the influence of 1.5 wt. % Bi in the Sn-0.7Cu solder soldered on copper organic solderability preservative (Cu-OSP) and immersion tin (Im-Sn) surface finish has improved the wettability and microhardness. Subsequently, the IMC thickness of Sn-0.7Cu+1.5Bi solder alloy on Im-Sn surface finish gives a better result than reflowed on Cu-OSP. Generally, with the addition of 1.5 wt. % Bi in Sn-0.7Cu solder alloy reflowed on the Im-Sn surface finish had enhanced the performance in terms of wettability, thickness of IMC and microhardness properties compared to on Cu-OSP surface finish

An Investigation of TiO2 Addition on Microstructure Evolution of Sn-Cu-Ni Solder Paste Composite

In this research, varying fraction of titanium oxide (TiO2) reinforcement particles was successfully incorporated into Sn-Cu-Ni solder paste in an effort to study the influence of TiO2 addition on microstructure evolution of Sn-Cu-Ni solder paste composite. Sn-Cu-Ni solder paste composite was produced by mixing TiO2 particle with Sn-Cu-Ni solder paste. The microstructure analysis was carried out by Scanning Electron Microscopy-Energy dispersive X-ray (SEM-EDX). The addition TiO2 particle helps to refine the bulk solder microstructure and suppress the intermetallic compound (IMC) formation at the interface as will be discussed further

An Investigation of TiO

In this research, varying fraction of titanium oxide (TiO2) reinforcement particles was successfully incorporated into Sn-Cu-Ni solder paste in an effort to study the influence of TiO2 addition on microstructure evolution of Sn-Cu-Ni solder paste composite. Sn-Cu-Ni solder paste composite was produced by mixing TiO2 particle with Sn-Cu-Ni solder paste. The microstructure analysis was carried out by Scanning Electron Microscopy-Energy dispersive X-ray (SEM-EDX). The addition TiO2 particle helps to refine the bulk solder microstructure and suppress the intermetallic compound (IMC) formation at the interface as will be discussed further