Effect of pcb cracks on thermal cycling reliability of. The solder joints frequently connect materials of highly disparate properties, causing global thermal expansion mismatches 123456, and are made of a material, solder, that itself has often properties significantly different than the bonding structure materials, causing local thermal expansion mismatches 4, 7. For a long time, tinlead alloys have been the main welding mate. The purpose of this study is to investigate the effect of aging temperature on the barreltype solder joint lifetime of electronic devices and to include these effects in pdf 1 mb reliability analysis of snagcu leadfree solder thermal interface materials in microelectronics. Correlationdriven machine learning for accelerated reliability. These reliability issues are quite complicated due to the combined effect of electrical, mechanical, chemical, and thermal forces on solder joints. Therefore, submodeling technique is a desirable choice. Jan 27, 2016 pdf download solder joint technology materials properties and reliability springer series in pdf full ebook.
Material properties, modelling, alloy design, thermodynamics, leadfree solder alloys. Cree xlamp leds solder joint reliability study cree, inc. Pdf the effects of aging temperature on sac solder joint. Chip scale package csp solder joint reliability and. Unintended stresses from potting, underfills and conformal coatings. Material behavior of eutectic solder alloys under various thermal conditions that leads to.
Achieving high reliability for leadfree solder joints. This is achieved by providing indepth studies on a number of major topics such as solder joints in conventional and advanced packaging components, commonly used leadfree materials. Traditional finite element based predictions for solder joint reliability during. Solder is the electrical and me chanical glue of electronic assemblies. One cannot assume that corrosion byproductsthat form in the joint are, themselves, structurally sound so as to replace the. A case study will evaluate the role of solder material and the joint. Effect of encapsulation materials on tensile stress during. Review and analysis of leadfree solder material properties. Solder paste is a complex material that has been likened to a mini chemical factory in a jar. The prediction of long term solder joint reliability, sjr, of microelectronic devices and packaging solutions continues to challenge the microelectronic packaging industry, particularly with the introduction of leadfree materials, the push for higher performance frequencyspeedthermal and lower unit. Techniques to evaluate solder fatigue behavior include finite element analysis and semianalytical closedform equations. The properties of different solder materials and their solder joints are also presented.
In the shear test, the shear strength of lap joint specimen was measured using cu plates as shown in fig. Several engineering models have been developed to predict solder joint reliability based on coffinmanson e. Solder joint reliability assessment for a high performance rf. Pdf thermomechanical fem analysis of lead free and lead. The prediction of long term solder joint reliability, sjr, of microelectronic devices and packaging solutions continues to challenge the microelectronic packaging industry, particularly with the introduction of leadfree materials, the push for higher performance frequencyspeedthermal and lower unit cost. The reliability of the solder joint attachments of electronic components surface mounted to.
Bozack center for advanced vehicle electronics auburn university auburn, al 36849 phone. The properties of solder have facilitated broad assembly choices that have fueled creative applications to advance technology. Materials, properties, and reliability solder joints are ubiquitous in electronic consumer products. The effect on the mechanical properties of adding the quaternary element bismuth to the sn3. Solder joints are ubiquitous in electronic consumer products.
Pdf reliability assessment of lead free solder joint. Although material properties are critical inputs for such types. Materials science and technology volume 34, 2018 issue 8. Typically, the main reliability issue is solder joint fatigue which accounts for a large amount of failures in electronic components. We need not look far to see solder being used to interconnect ever finer geo metries. Sn packaging technology, the c4 solder joints used in. For example, spontaneous sn whisker growth and electromigration induced failure in solder joints are serious issues. Fatigue properties and microstructure of snagcu bibased.
Solder interconnect reliability is the ability of a solder joint to retain full functionality in a use environment. This is because the demands on paste are varied and can only be met by a sophisticated system that utilizes the most recent advances in chemical technology. Microstructure and reliability of mo nanoparticle reinforced sn58bi. Improved predictions of lead free solder joint reliability that include. Solder attachment reliability a physics of failure approach. Mechanical properties and solder joint reliability of low. These models are often used when trying to assess solder joint reliability. This book provides a comprehensive overview of important aspects of solder materials including solderability and soldering reaction, physical metallurgy, mechanical properties, electromigration, and reliability of solder joint.
In order to improve the reliability, a variety of wlp technologies have been developed fan et al. Solder joint reliability assessment for a high performance. The fatigue life of a solder joint depends on several factors including. After the surface of the cu plates was electrolytically polished, the joining area 3 3mm2 was pretinned with a. Solder is melted in order to adhere to and connect the pieces after cooling, which requires that an alloy suitable for use as solder have a lower melting point than the pieces being joined.
Figure 1 fem mesh for the underfilled 10x10 mm 2 flip chip assembly mounted on a 1 mm thick fr4 boardbesides the possible discrepancy in the results due to the material properties used in the model, the actual simulation methodology used to represent electronic assemblies and solder joints is a source of variation for life prediction models. Processing and reliability assessment of solder joint. After thermal cycling, cracks were observed in the pcb under the solder joints. Here the plastic deformation behaviour of a sac alloy is characterised.
The solder joints reliability not only depends on the solder joint alloys, but also on the component and pcb. Solder joint function, properties, behavior and models. Solder used in making electrical connections also needs to have favorable electrical characteristics. The solder joints under thermal stresses exhibit fairly complex phenomena due to the presence of many variables and their ensuing effects such as. Sufficient displacement amplitude required to obtain plastic deformation in solder. Electronics packaging technology conference eptc, 2011 ieee th. Pdf may be used to describe point behavior of solder material undergoing. Assembly and reliability of leadfree solder joints by john h. In this book, the advanced materials reliability issues related to coppertin reaction and electromigration in solder joints are emphasized and methods to prevent these reliability problems are. Solder joint reliability theory and applications john h. Effects of design, structure and material on thermal. Correlation of material properties to the reliability. However, the mechanical and fatigue properties of the actual solder joint structure have not been studied for these new alloys. Solder joint cracking appeared at the interface between the copper trace and the solder material on the component side and propagated almost parallel to the interface.
Pdf solder reactions on nickel, palladium, and gold. Solder joint technology materials properties and reliability. There are several materials involved with different wlp structures. In this book, the advanced materials reliability issues related to coppertin reaction and electromigration in solder joints are emphasized and methods to prevent these reliability problems are discussed. Solder joint reliability theory and applications john. Pdf leadfree solder joint reliabilitystate of the art and. Solder joint technology materials, properties, and reliability. This can often occur at stress levels below the yield stress of solder as a result of repeated temperature fluctuations, mechanical vibrations, or mechanical loads. Solder joints are subjected to fluctuating strains due to cte mismatches between the chip. Materials, properties, and reliability springer series in materials science 92 2007th edition by kingning tu author 5. To improve solder joint reliability, the science of solder joint behavior under various driving forces must be understood. Lead and package geometry influences solder joint response to mechanical loads. Mechanical properties and microstructure investigation of. They proved that these metals can increase the drop shock reliability of leadfree solder joints.
Reliability issues of leadfree solder joints in electronic devices. The results of this research study provide necessary data for the modeling of solder joint reliability for a range of snagcu compositions and a baseline. Jun 23, 2020 the reliability of solder joints plays a critical role in electronic assemblies. Therefore, it is necessary to understand the effect of polymer encapsulations coatings, pottings and underfills on the solder joints when predicting reliability. Solder fatigue in electronics components is the results of temperature fluctuations or mechanical loads transmitted to the components through the assembly. Solder fatigue is the mechanical degradation of solder due to deformation under cyclic loading. Pdf download solder joint reliability of bga csp flip chip. In addition, the measures to improve the reliability of solder joints are.
One of the major reliability limiting factors of flip chip solder joints is solder fatigue by thermalpower cycling. The attachment of terminations in the manufacture of silver ceramic capacitors is a typical application. Materials, properties, and reliability, paperback by tu, kingning, isbn 1441922849, isbn 9781441922847, like new used, free shipping in the us. Dimensions, structural design, and material properties have. Reliability of leadfree solder joints unimap portal. Solder geometry will dictate the stress distribution at the interface. This pervasive dependency on solder has stimulated new interest in applica tions as well as a more concerted effort to better understand materials properties. In this book, the advanced materials reliability issues related to coppertin reaction. The effects of aging temperature on sac solder joint material behavior and reliability yifei zhang, zijie cai, jeffrey c. Pbsn longer fatigue life and better solder joint reliability reduced shock performance vs. In this book, the advanced materials reliability issues related to coppertin rea. Investigation of the mechanical properties of mnalloyed tin. This book focuses on the assembly and reliability of leadfree solder joints.
Solder joint technology materials, properties, and. Therefore, this study was focused on degradation characteristics of sn3. Physics of failure reliability physics definitions o reliability physics a. In this book, the advanced materials reliability issues related to coppertin reaction and electromigration. The solder should also be resistant to oxidative and corrosive effects that would degrade the joint over time. Material loss degrades the joint s capacity to support a mechanical load, provide hermetically for a container structure, or sustain continuity in an electrical circuit.
Both the principles and engineering practice are addressed, with more weight placed on the latter. The most insidious environments for solder degradation are hightemperature aging and thermomechanical fatigue because solders are microstructurally. Solder paste is composed of a solder powder and a solder flux or vehicle system. Solder joint reliability is a major concern for area array technologies and power chip interconnection, thus the second objective of this study is to evaluate solder joint reliability, investigate the fatigue failure behavior of solder joint and improve solder joint reliability by developing a new solder bumping process for improved solder. Institute of materials science at tampere university of technology. Figure 3 illustrates the surfacemount technology smt reflow. The calculation of material properties has been made possible in recent years following the development of jmatpro computer software 6. For example, one of the earliest and wellknown solder joint reliability models is the norrislandzberg 1969 model for nonunderfilled flipchip assemblies. Solder is a fusible metal alloy used to create a permanent bond between metal workpieces. Pdf download solder joint reliability of bga csp flip. Such material properties are also critical inputs for the manufacturing and reliability modelling of soldered components or systems using finite element or finite difference simulation tools. While some of the lessons learned with snpb will transfer to leadfree applications, a significant amount of research and development is needed for leadfree reliability models to come up. Solder joint technology materials, properties, and reliability svny339tu april 6, 2007 10. Pdf microstructure and mechanical properties of leadfree solders.
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