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In this paper, the material characteristics of six epoxies used for corner/edge-bonding are analyzed and compared to board-level mechanical reliability test. An innovative material characterization approach, button shear testing, provided an expedient method of determining adhesive strength between the epoxies and each relevant surface material. The board-level test included mechanical shock test...
More and more reliability and quality problems of electrical assemblies have to be solved due to the trend of miniaturization and the even higher level of integration. In some cases these failures can lead to catastrophic failure. The phenomenon of electrochemical migration is one of the most dangerous failure mechanism which usually results in short resistive circuits. In this paper electrochemical...
Stiffness of printed circuit boards (PCB) has a great impact on reliability of solder joints. Vibrations or external stress loading lead to stress accumulation within solder joint area. Depending on intensity, inducted stress can be relieved by creep or fractures of solder joint. Intensity of inducted stress depends on loading conditions as well as properties of joined materials (specially stiffness...
In case of prototyping and small series it can be identified a common practical issue for EMS (Electronic Manufacturing Services) companies, especially in case of prototyping and small series activities, regarding solder paste loss percent, production costs and solder joints reliability consequences. Although the solder pastes producers assure minimum 8 hours stencil life-STL (the warranted solder...
Driven by legislation in the European Union and international industry activities for the use of environment-friendly technologies, automotive suppliers and OEMs are faced with the demand to substitute lead-containing solders in electronic assemblies. Compared to consumer electronics, for which lead-containing technologies had to be phased out by July 2006, automotive applications have to meet considerably...
Investigation is connected with development of lead free technology for production of electronic devices for automotive industry. Strong requirements for reliability in this industry demands high quality of solder joints and multifarious tests of the devices. The purpose of this article is to present the methods and the results of environmental tests for electronic controllers produced by lead-free...
Investigation deals with development of lead-free technology for production of electronic devices for automotive industry. The purpose of this article is to present the results concerning solder joints quality evaluated by X-ray and scanning acoustic microscopy (SAM). Strong requirements for reliability in automotive industry demands high quality of solder joints of the devices. Experiments are devoted...
Two goals of the work - verification of suitability of mechanical tests of solder joints reliability and infant mortality (early failures) of lead-free joints are selected. The results of reliability tests of lead - free solder joints of SMT resistors showed a tendency to increase of infant mortality failure rate comparing to SnPb eutectic joints. These new results are presented. Soldering process...
This paper will describe a new technique to increase the reliability of wafer-level packages (WLPs). The technique enables the placement of a protective coating around the solder balls using a maskless process and provides improved reliability performance as compared to unprotected devices. In addition, the unbonded devices allow for easier handling. This approach also minimizes form factor requirements...
The excessive growth of intermetallic compound (IMC) and the formation of microvoids in the interface between Sn-Ag-Cu (SAC) solder and Cu substrate have been a serious problem which may degrade the solder joints reliability. Recently, a new Cu-Zn alloy solder wetting layer for the Pb-free solders has been developed to reduce the IMC growth rate. In this paper, the kinetics of IMC growth and the shear...
Leading indicators of failure have been developed based on high-frequency characteristics, and system-transfer function derived from resistance spectroscopy measurements during shock and vibration. The technique is intended for condition monitoring in high reliability applications where the knowledge of impending failure is critical and the risks in terms of loss-of-functionality are too high to bear...
Failure of organic packages is often accelerated by mechanical failure of an underfill designed to protect the solder joints. The crack growth rate of an underfill under thermal cycling is crucial for package reliability and lifetime prediction. Mechanically-induced fatigue crack growth results have been used in package reliability studies, but thermally-induced fatigue crack growth data for underfills...
Predictive modeling tools and techniques, whether computer-aided, such as, e.g., finite-element analysis (FEA), or analytical (ldquomathematicalrdquo), are currently widely used in physical design and reliability evaluations in electronics engineering. The implementation of these tools and techniques requires accurate input data for obtaining trustworthy output information that is intended to be used...
Portable products as well as some larger products may see failures by a high strain rate mechanical loading like that seen in a high or low level drop/shock event. Within the portable product industry there is a wide range of product design, usage and loading conditions. Because of this, standards such as JEDEC, which is meant to generate comparative results addressing component reliability, do little...
A new low-cost flip-chip technology that leverages the existing fine pitch flip-chip technologies is discussed. For decades, the C4 process has served as the main interconnect method in the flip-chip package. However with bump pitches shrinking, the solder bump based C4 process is facing challenges in terms of reducing pitch and underfill process. At the same time, increasing challenges for flip-chip...
Sn-8Zn-3Bi solder balls with different weight percentages of Sn-Ag-Cu addition were bonded to Au/Ni metallized Cu pads, and the effect of multiple reflow and aging on impact reliability was investigated. In the Sn-Ag-Cu content Sn-Zn-Bi solder joints, the AgZn3 intermetallic compound layer was clearly observed at the interfaces and its thickness increased with an increase the number of reflow cycles...
This paper described a ceramic ball grid array (CBGA) and its second level reliability. The CBGA uses a substrate with high coefficient of thermal expansion (CTE) and leadfree soldering. The reworkability of the BGA package and board was also studied. The results have shown that this package is reworkable without a significant reliability reduction in the board level reliability. The reliability of...
Two commonly used Pb-free solders, SnAg and SnCu, are studied for electromigration (EM) reliability. Two major EM failure mechanisms are identified in Sn-based Pb-free solders, which is mainly due to the differences in microstructures and Sn-grain orientation. In general, the EM damage in SnCu solder is driven by the fast interstitial diffusion of Ni and Cu away from solder/UBM interface and leads...
The analysis process and methods of a failure BGA solder joint have been studied by a failure analysis case for an actual BGA package sample with XRD, cross section analysis and SEM&EDS analysis. The analysis results show that the cracks are the main failure causes of the BGA solder joints. The position of cracks appeard between the IMC and PCB pad and the interface of solder and IMC. The main...
Reliability of SnAgCu solder joints under mechanical stress is not proven, in particular for Aeronautic and High Performance (AHP) products. They are subjected to high temperatures, severe mechanical stresses and long-term mission profiles. This work is comprehended within a larger study, which has as objective the characterization of the SnAgCu alloys mechanical behaviour at the solder joint scale...
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