Effect on Shear Strength and Hardness Properties of Tin Based Solder Alloy, Sn-50Bi, Sn-50Bi+2%TiO2 Nanoparticles

2020 ◽  
Vol 1159 ◽  
pp. 54-59
Author(s):  
Singh Amares ◽  
Bandar Tchari
Keyword(s):  
Shear Strength ◽  
Melting Temperature ◽  
Solder Alloy ◽  
Vickers Hardness ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Lead Free ◽  
The European Union ◽  
Solder Alloys ◽  
Free Solder

Solder alloys are important joining medium widely used in the electronics industry to connect components to printed circuit board PCB. The Sn-Pb solder alloys have been the cornerstone medium used for a long time. Unfortunately, the use of Pb was banned by the European Union due to the harmful environmental and health issues with Pb. Therefore, in this study, the Sn-50Bi and Sn-50Bi+2%TiO2 nanoparticles lead-free solder alloy is investigated based on their shear strength, Vickers hardness, and melting temperature. The investigation shows that the hypo eutectic Sn-50Bi has a low melting temperature of approximately 145°C, and the 2%TiO2 nanoparticles reinforced Sn-50Bi has a melting temperature of around 182°C, which is lower than the traditional Sn-Pb (Tm=183 °C) and Sn-Ag-Cu (Tm=227°C). Furthermore, the developed Sn-50Bi had a Vickers hardness and shear strength of 26.81 HV and 40.78 MPa respectively, higher than the other leaded and lead-free solders. However, after the reinforcement, the hardness increased by 12% (30 HV) and a slight increase of 2.5% (42.4MPa) in shear strength. Overall, the addition of the TiO2 nanoparticles showed a clear influence on the Sn-Bi properties. The results obtained from this study seem satisfactory to the electronic industry and the environment.

Materials Characterization of Lead Free Compositions for Minimum Temperature SMT Processes at the SLI-Second Level Interconnect Solder Joint

2004 ◽  
Author(s):  
Norman J. Armendariz ◽  
Prawin Paulraj
Keyword(s):  
Solder Joint ◽  
Printed Circuit Board ◽  
Gold Surface ◽  
Circuit Board ◽  
Lead Free ◽  
Processing Temperature ◽  
The European Union ◽  
Printed Circuit ◽  
Higher Temperature ◽  
Tin Silver Copper

Abstract The European Union is banning the use of Pb in electronic products starting July 1st, 2006. Printed circuit board assemblies or “motherboards” require that planned CPU sockets and BGA chipsets use lead-free solder ball compositions at the second level interconnections (SLI) to attach to a printed circuit board (PCB) and survive various assembly and reliability test conditions for end-use deployment. Intel is pro-actively preparing for this anticipated Pb ban, by evaluating a new lead free (LF) solder alloy in the ternary Tin- Silver-Copper (Sn4.0Ag0.5Cu) system and developing higher temperature board assembly processes. This will be pursued with a focus on achieving the lowest process temperature required to avoid deleterious higher temperature effects and still achieve a metallurgically compatible solder joint. One primary factor is the elevated peak reflow temperature required for surface mount technology (SMT) LF assembly, which is approximately 250 °C compared to present eutectic tin/lead (Sn37Pb) reflow temperatures of around 220 °C. In addition, extended SMT time-above-liquidus (TAL) and subsequent cooling rates are also a concern not only for the critical BGA chipsets and CPU BGA sockets but to other components similarly attached to the same PCB substrate. PCBs used were conventional FR-4 substrates with organic solder preservative on the copper pads and mechanical daisychanged FCBGA components with direct immersion gold surface finish on their copper pads. However, a materials analysis method and approach is also required to characterize and evaluate the effect of low peak temperature LF SMT processing on the PBA SLI to identify the absolute limits or “cliffs” and determine if the minimum processing temperature and TAL could be further lowered. The SLI system is characterized using various microanalytical techniques, such as, conventional optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and microhardness testing. In addition, the SLI is further characterized using macroanalytical techniques such as dye penetrant testing (DPT) with controlled tensile testing for mechanical strength in addition to disbond and crack area mapping to complete the analysis.

Effect of Sb additions on the creep behaviour of low temperature lead-free Sn–8Zn–3Bi solder alloy

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Guang Ren ◽  
Maurice Collins
Keyword(s):  
Low Temperature ◽  
Solder Alloy ◽  
Creep Behaviour ◽  
Lead Free ◽  
Coefficient Of Determination ◽  
Secondary Creep ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
Content Type ◽  
Free Solder

Purpose This paper aims to investigate the creep behaviour of the recently developed Sn–8Zn–3Bi–xSb (x = 0, 0.5, 1.0 and 1.5) low temperature lead-free solder alloys. Design/methodology/approach An in-house compressive test rig was developed to perform creep tests under stresses of 20–40 MPa and temperature range 25°C–75 °C. Dorn power law and Garofalo hyperbolic sine law were used to model the secondary creep rate. Findings High coefficient of determination R2 of 0.99 is achieved for both the models. It was found that the activation energy of Sn–8Zn–3Bi solder alloy can be significantly increased with addition of Sb, by 60% to 90 kJ/mol approximately, whereas the secondary creep exponent falls in the range 3–7. Improved creep resistance is attributed to solid solution strengthening introduced by micro-alloying. Creep mechanisms that govern the deformation of these newly developed lead-free solder alloys have also been proposed. Originality/value The findings are expected to fill the gap of knowledge on creep behaviour of these newly developed solder alloys, which are possible alternatives as lead-free interconnecting material in low temperature electronic assembly.

Site Redressing Techniques and Rework of Lead-Free Chip Scale Packages

2003 ◽  
Author(s):  
Arun Gowda ◽  
Anthony Primavera ◽  
K. Srihari
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Paste ◽  
Printed Circuit ◽  
Free Solder ◽  
The Individual ◽  
Component Assembly ◽  
Free Area

The implementation of lead-free solder into an electronics assembly process necessitates the reassessment of the individual factors involved in component attachment and rework. A component assembly undergoes multiple thermal cycles during rework. With the use of lead-free solder, the assemblies are subjected to higher assembly and rework temperatures than those required for eutectic tin-lead assemblies. The rework of lead-free area array components involves the removal of defective component, preparation of the printed circuit board attachment pad (site redressing), solder paste replenishment or flux deposition, and component placement and reflow. This paper primarily focuses on the site redressing aspect of lead-free rework, followed by the development of rework processes for lead-free chip scale packages utilizing the knowledge gained in the site redressing studies.

Physical and Mechanical Behaviors of SnCu-Based Lead-Free Solder Alloys with an Addition of Aluminium

2015 ◽  
Vol 815 ◽  
pp. 64-68 ◽  
Author(s):  
Nisrin Adli ◽  
Nurul Razliana Abdul Razak ◽  
Norainiza Saud
Keyword(s):  
Melting Point ◽  
Solder Alloy ◽  
Lead Free ◽  
Lead Free Solder ◽  
Mechanical Behaviors ◽  
Solder Alloys ◽  
Al Content ◽  
Homogenous Distribution ◽  
Lead Free Solder Alloy ◽  
Free Solder

The effect of Al addition on the microstructure, melting point and microhardness of SnCu-Al lead-free solder alloys were investigated with two different compositions of Al which were 1 wt% and 5 wt%. These solder alloys were fabricated through powder metallurgy (PM) method. The results showed that the melting point and the microhardness value of the SnCu-Al lead-free solder alloy were increased as the Al content increased from 1 wt% to 5 wt%. The grain growth of SnCu-Al lead-free solder alloy also tends to be retarded due to the homogenous distribution of Al at the grain boundaries.

The Role of Pb Impurity in SAC Solder Alloy

2013 ◽  
Vol 752 ◽  
pp. 42-47
Author(s):  
Gréta Gergely ◽  
Alíz Molnár ◽  
Zoltán Gácsi
Keyword(s):  
European Union ◽  
Intermetallic Compounds ◽  
Solder Alloy ◽  
Hazardous Substances ◽  
Lead Free ◽  
Lead Free Solder ◽  
The European Union ◽  
Free Solder ◽  
Sac Solder

The European Union and Japan initiated the issue of RoHS, the directive about the restriction of hazardous substances, which prohibits certain hazardous substances in electronic equipment - including lead - application. Due to the directive the use of lead free solder alloys is spreaded, however the Pb in the form of contamination may be appear under technological process. The lead impurity has significant effect on microstrucutre and lifetime so it is necessary to carry out detailed examinations. In this paper the study of intermetallic compounds in six-element, Pb impured, thermal cycles test-subjected, Sn-Ag-Cu (SAC) solder alloy is demonstrated

Failure Analysis Techniques for Lead-Free Solder Joints

2005 ◽  
Author(s):  
Todd Castello ◽  
Dan Rooney ◽  
Dongkai Shangguan
Keyword(s):  
Failure Analysis ◽  
Printed Circuit Board ◽  
Failure Modes ◽  
Circuit Board ◽  
Lead Free ◽  
Lead Free Solder ◽  
Printed Circuit Board Assembly ◽  
Analysis Techniques ◽  
Solder Interconnects ◽  
Free Solder

Abstract Printed circuit board assembly with lead free solder is now a reality for most global electronics manufacturers. Extensive research and development has been conducted to bring lead free assembly processes to a demonstrated proficiency. Failure analysis has been an integral part of this effort and will continue to be needed to solve problems in volume production. Many failure analysis techniques can be directly applied to study lead free solder interconnects, while others may require some modification in order to provide adequate analysis results. In this paper, several of the most commonly applied techniques for solder joint failure analysis will be reviewed, including visual inspection, x-ray radiography, mechanical strength testing, dye & pry, metallography, and microscopy/photomicrography, comparing their application to lead bearing and lead free solder interconnects. Common failure modes and mechanisms will be described with examples specific to lead free solders, following PCB assembly as well as after accelerated reliability tests.

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