Technical Library | 2018-06-18 13:43:56.0
Thermal influences can significantly compromise the service life, capacity and especially the operational safety of HV batteries. In order to prevent damage due to excessive temperatures, large quantities of heat-conducting potting media are used here. Scheugenpflug has developed a new system solution for fast and reliable application of these materials.
Technical Library | 2010-01-06 22:27:03.0
Increased functionality and performance requirements for microprocessors and ASICs have resulted in a trend to package these devices in the flip-chip BGA form factor (FCBGA). Because these devices use in excess of 40-100 Watts of power, their packages must dissipate heat in an extremely efficient manner. Most semiconductor companies have developed some type of thermally enhanced FCBGA package that provides heat dissipation through the back of the die to a heat spreader.
Technical Library | 2020-09-30 19:26:45.0
Introduction •Market trend: Smaller, more efficient, more powerful, run faster •ICs and other sophisticated electronic components typically operate efficiently only under a certain range of temperatures •Operational temperatures must be kept within a suitable range • Excessive heat can damage performance and can even cause system failure
Technical Library | 2022-03-16 19:48:18.0
Dendrites, Electrochemical Migration (ECM) and parasitic leakage, are usually caused by process related contamination. For example, excess flux, poor handling, extraneous solder, fibers, to name a few. One does not normally relate these fails with environmental causes. However, creep corrosion is a mechanism by which electronic products fail in application, primarily related to sulfur pollution present in the air.1 The sulfur reacts with exposed silver, and to a lesser extent, exposed copper. This paper will explore various aspects of the creep corrosion chemical reaction
Technical Library | 2020-01-01 17:06:52.0
The majority of electronic failures occur due to thermally induced stresses and strains caused by excessive differences in coefficients of thermal expansion (CTE) across materials.CTE mismatches occur in both 1st and 2nd level interconnects in electronics assemblies. 1st level interconnects connect the die to a substrate. This substrate can be underfilled so there are both global and local CTE mismatches to consider. 2nd level interconnects connect the substrate, or package, to the printed circuit board (PCB). This would be considered a "board level" CTE mismatch. Several stress and strain mitigation techniques exist including the use of conformal coating.
Technical Library | 2015-03-26 19:16:03.0
Nickel-palladium-gold-finished terminals are susceptible to creep corrosion. Excessive creep corrosion can result in device failure due to insulation resistance loss between adjacent terminals. The mixed flowing gas test has been demonstrated to produce creep corrosion on parts with nickel-palladium-gold finished terminals. Conformal coats are often used to protect printed wiring assemblies from failure due to moisture and corrosion. However, coating may not be sufficient to protect lead terminations from failure.In this study, acrylic, silicone, urethane, parylene, and atomic layer deposit (ALD) coatings were examined for their effectiveness at preventing corrosion of nickel-palladium-gold-finished terminals.
Technical Library | 2007-08-09 12:23:10.0
Recent developments in No Flow-Fluxing Underfill (NFFUF) products have demonstrated their utility to enhance the reliability of flip chip assemblies with reduced processing steps over conventional capillary flow methods. This basic work considered processing conditions such as dispensed volume and placement force, speed and dwell time. Further evaluations of these new products on a variety of flip chip assembly configurations manufactured by various processes have been undertaken to provide further evidence of their suitability and potential in high volume electronic manufacturing. This paper summarizes the recent evaluations and discusses new studies of additional assembly configurations, which include higher input/output (l/O) counts up to full arrays in excess of 1200 l/Os.
Technical Library | 2013-01-03 20:27:54.0
Electronics assemblies with large flip-chip BGA packages can be prone to either pad cratering or brittle intermetallic (IMC) failures under excessive PCB bending. Pad cratering cracks are not detected by electrical testing or non-destructive inspection methods, yet they pose a long term reliability risk since the cracks may propagate under subsequent loads to cause electrical failure. Since the initiation of pad cratering does not result in an instantaneous electrical signature, detecting the onset of this failure has been challenging. An acoustic emission methodology was recently developed by the authors to detect the onset of pad cratering. The instantaneous release of elastic energy associated with the initiation of an internal crack, i.e., Acoustic Emission (AE), can be monitored to accurately determine the onset of both pad cratering and brittle intermetallic (IMC) failures.
Technical Library | 2014-03-06 19:04:07.0
Over the last few years, there has been an increase in the rate of Head-in-Pillow component soldering defects which interrupts the merger of the BGA/CSP component solder spheres with the molten solder paste during reflow. The issue has occurred across a broad segment of industries including consumer, telecom and military. There are many reasons for this issue such as warpage issues of the component or board, ball co-planarity issues for BGA/CSP components and non-wetting of the component based on contamination or excessive oxidation of the component coating. The issue has been found to occur not only on lead-free soldered assemblies where the increased soldering temperatures may give rise to increase component/board warpage but also on tin-lead soldered assemblies.
Technical Library | 2022-12-23 20:44:54.0
One of the upcoming reliability issues which is related to the lead-free solder introduction, are the headin-pillow solderability problems, mainly for BGA packages. These problems are due to excessive package warpage at reflow temperature. Both convex and concave warpage at reflow temperature can lead to the head-in-pillow problem where the solder paste and solder ball are in mechanical contact but not forming one uniform joint. With the thermo-Moiré profile measurements, this paper explains for two flex BGA packages the head-in-pillow. Both local and global height differences higher than 100 µm have been measured at solder reflow temperature. This can be sufficient to have no contact between the molten solder ball and solder paste. Finally, the impact of package drying is measured
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