Temperature Cycling Study of Aerosol-Jet Printed Conductive Silver Traces in Printed Electronics

Aerosol-Jet Printing (AJP) provides a new method for electronic component manufacturing. Understanding the reliability of electronics printed using the AJP process is essential to take full advantage of this technology and realize its industrial potential. In the current study, we have designed and tested AJP printed samples and conducted failure analysis of those samples that have exhibited early failures. Failures first occurred in the short traces that connect the main traces to the silver pads, due to local stress-raisers caused by local geometric features in the printing geometry. Thermal-Mechanical Finite-Element-Modeling (FEM) has been performed to analyze the cyclic history of thermo-mechanical stress distribution and plastic strain distribution.

Interface Energy-driven Indium Whisker Growth on Ceramic Substrates

The mechanism behind spontaneous growth of metal whiskers is essential to develop lead-free whisker mitigation strategy for the sake of long-term reliability of electronics, and has been sought for several decades. However, a consensus about it still lacks, and a host of factors influencing the phenomenon have been investigated, but the role of interface energy has not been paid adequate attention. In this study, the whisker growth propensities of ball-milled Ti2InC/In and non-MAX phase TiC/In and SiC/In are comparatively studied in the terms of the wettability, thermal behavior and crystal structures. The wetting angles of indium with Ti2InC, TiC, and SiC (144.4°, 155.7°, and 142.2°, respectively) are large and quite close, indicating the poor wettability between liquid indium and the three ceramics. The thermal behaviors of all the three systems have obvious changes after ball milling. The number density of indium whiskers on ball-milled Ti2InC are significantly greater than those on the TiC and SiC substrates, which is explained based on interface energy and the crystal structure difference of the ceramic substrates.

On the 3-D Shape of Interlaced Regions in Sn-3Ag-0.5Cu Solder Balls

The microstructure of Sn-Ag-Cu (SAC) solder joints plays an important role in the reliability of electronics, and interlaced twinning has been linked with improved performance. Here, we study the three-dimensional (3-D) shape of interlaced regions in Sn-3.0Ag-0.5Cu (SAC305) solder balls by combining serial sectioning with electron backscatter diffraction. In solder balls without large Ag3Sn plates, we show that the interlaced volume can be reasonably approximated as a hollow double cone with the common 〈100〉 twinning axis as the cone axis, and the 〈110〉 from all three twinned orientations making up the cone sides. This 3-D morphology can explain a range of partially interlaced morphologies in past work on 2-D cross-sections.

Impact of Immersion Cooling on Thermo-Mechanical Properties of PCB’s and Reliability of Electronic Packages

Immersion cooling is highly efficient thermal management technique and can potentially be used for thermal management of high-density data. However, to use this as a viable cooling technique, the effect of dielectric coolants on the reliability of server components needs to be evaluated. Previous work reported contradicting findings for Young’s modulus of PCBs, providing motivation for this work. This study focuses on effect of immersion cooling on the mechanical properties of printed circuit board (PCB) and its impact on reliability of electronic packages. Changes in thermo-mechanical properties like Young’s modulus (E), Glass transition temperature (Tg), of PCB and its layers due to aging in dielectric coolant are studied. Two types of PCBs using different material namely 370HR and 185HR are studied. To characterize Young’s modulus and Tg dynamic mechanical analyzer (DMA) is used. Major finding is Young’s modulus is decreasing for PCBs after immersion in dielectric coolant which is likely to increase reliability of electronics package.

ASSESSMENT OF RELIABILITY OF ELECTRONICS COMPONENTS USING STATISTICAL PREDICTION METHODS

Ithin the framework of this article the question of gamma‑percentile time to failure of the electronic components of domestic production with strict performance requirements for resistance to external factors, as well as reliability, is considered. By now requirements in terms of gamma‑percentile time to failure of electronic components, used as part of advanced electronic equipment, reaching 150,000 hours under value of γ = 99%. Due to the increase in requirements for these products in terms of reliability, there is a need to develop new ideas and methods of reliability theory. In this article it is proposed to estimate the gamma‑percentile time to failure on the basis of the results of measurements of parameters‑criteria of validity, controlled by accelerated tests for reliability.