Technical Library | 2021-05-13 16:03:25.0
Sn-based lead-free solders such as Sn-Ag-Cu, Sn-Cu, and Sn-Bi have been used extensively for a long time in the electronic packaging field. Recently, low-temperature Sn-Bi solder alloys attract much attention from industries for flexible printed circuit board (FPCB) applications. Low melting temperatures of Sn-Bi solders avoid warpage wherein printed circuit board and electronic parts deform or deviate from the initial state due to their thermal mismatch during soldering. However, the addition of alloying elements and nanoparticles Sn-Bi solders improves the melting temperature, wettability, microstructure, and mechanical properties. Improving the brittleness of the eutecticSn-58wt%Bi solder alloy by grain refinement of the Bi-phase becomes a hot topic. In this paper, literature studies about melting temperature, microstructure, inter-metallic thickness, and mechanical properties of Sn-Bi solder alloys upon alloying and nanoparticle addition are reviewed
Technical Library | 2022-10-31 17:25:37.0
Mixed formulation solder alloys refer to specific combinations of Sn-37Pb and SAC305 (96.5Sn–3.0Ag–0.5Cu). They present a solution for the interim period before Pb-free electronic assemblies are universally accepted. In this work, the surfaces of mixed formulation solder alloys have been studied by in situ and real-time Auger electron spectroscopy as a function of temperature as the alloys are raised above the melting point. With increasing temperature, there is a growing fraction of low-level, bulk contaminants that segregate to the alloy surfaces. In particular, the amount of surface C is nearly _50–60 at. % C at the melting point. The segregating impurities inhibit solderability by providing a blocking layer to reaction between the alloy and substrate. A similar phenomenon has been observed over a wide range of (SAC and non-SAC) alloys synthesized by a variety of techniques. That solder alloy surfaces at melting have a radically different composition from the bulk uncovers a key variable that helps to explain the wide variability in contact angles reported in previous studies of wetting and adhesion. VC 2011 American Vacuum Society. [DOI: 10.1116/1.3584821]
Technical Library | 1999-05-09 14:14:51.0
With the ongoing concern regarding environmental pollutants, Iead is being targeted in the electronic assembly arena. This paper highlights lead-free solders and the different combinations of elemental makeups.
Technical Library | 2014-10-02 20:10:07.0
Sn3.0Ag0.5Cu (SAC305) is the most popular near eutectic lead-free alloy used in the manufacturing processes. Over the last several years, the price of silver has dramatically increased driving a desire for lower silver alloy alternatives. As the results, there is a significant increase in the number of alternative low/no silver lead-free solder alloys available in the industry recently.In this paper, we'll present the performance and process capability of various low/no silver alloy solder pastes. Data from printability, wetting test, slump test, solder ball test, voiding, etc… will be discussed and compared with the control SAC305 solder paste. Benefits and concerns of using low/no silver alloy solder paste materials will also be addressed.
Technical Library | 2014-11-28 15:55:13.0
A soldering alloy composition Sn40-Bi60 has been manufactured by quenching method to achieve the both cast and wire shape. Differential scanning calorimetric (DSC) was done to study the melting behavior for a large portion of the alloy melts sharply at a approximately 136 C0 ,the melting point of Sn-Bi. X-Ray diffraction and optical microscopy were used to analyzed its microstructure characterization. The hardness of the alloys has been tested and find at a value 2 HRB as ductile form.
Technical Library | 2021-09-08 13:43:56.0
Manganese can be an optimal alloying addition in lead-free SAC (SnAgCu) solder alloys because of its low price and harmless nature. In this research, the mechanical properties of the novel SAC0307 (Sn/Ag0.3/Cu0.7) alloyed with 0.7 wt.% Mn (designated as SAC0307-Mn07) and those of the traditionally used SAC305 (Sn96.5/Ag3/Cu0.5) solder alloys were investigated by analyzing the shear force and Vickers hardness of reflowed solder balls. During the preparation of the reflowed solder balls, different cooling rates were used in the range from 2.7 K/s to 14.7 K/s.
Technical Library | 2013-10-17 17:46:01.0
Although several commercial and experimental Pb-free solder alloys are available as replacements for Sn-Pb solders, the following families of solders are of particular interest and are the prevailing choices of industry: eutectic Sn-Ag, eutectic Sn-Cu, eutectic Sn-Zn, eutectic Bi-Sn, and Sn–In. Since the properties of the binary Pb-free solders cannot fully meet the requirements for applications in electronic packaging, additional alloying elements are added to improve the performance of these alloys. Thus, ternary and even quaternary Pb-free solders have been developed, such as Sn-Ag-Cu, Sn-Ag-Bi, and Sn-Zn-Bi solder...
Technical Library | 2016-09-01 16:21:11.0
Sn3.0Ag0.5Cu (SAC305) is currently the most popular near eutectic lead-free alloy used in the manufacturing processes. Over the last several years, the price of silver has dramatically increased driving a desire for lower silver alloy alternatives. As a result, there is a significant increase in the number of alternative low/no silver lead-free solder alloys available in the industry recently. Our previous study showed that many alternative low silver solder paste materials had good printing and wetting performance as compared to SAC305 solder pastes. However, there is lack of information on the reliability of alternative alloy solder joints assembled using alternative low silver alloy solder pastes.In this paper, we will present the reliability study of lead-free solder joints reflowed using various lead-free alloy solder pastes after thermal cycling test (3000 cycles, 0°C to 100°C). Six different lead-free pastes were investigated. SAC305 solder joints were used as the control. Low and no silver solder pastes and a low temperature SnBiAg solder pastes were also included.
Technical Library | 2019-01-09 19:19:52.0
The electronics industry has widely adopted Sn-3.0Ag-0.5Cu solder alloys for lead-free reflow soldering applications and tin-copper based alloys for wave soldering applications. In automated soldering or rework operations, users may work with Sn-Ag-Cu or Sn-Cu based alloys. One of the challenges with these types of lead-free alloys for automated / hand soldering operations, is that the life of the soldering iron tips will shorten drastically using lead-free solders with an increased cost of soldering iron tool maintenance/ tip replacement. Development was done on a new lead-free low silver solder rework alloy (Sn-0.3Ag-0.7Cu-0.04Co) in comparison with a number of alternative lead-free alloys including Sn-0.3Ag-0.7Cu, Sn-0.7Cu and Sn-3.0Ag-0.5Cu and tin-lead Sn40Pb solder in soldering evaluations.
Technical Library | 2009-02-13 12:29:39.0
To meet the market demand for a best-in-class, low-cost leadfree alloy for wave, selective and dip soldering
