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An electrodynamic shaker is used to reduce the testing time and the costs of the mechanical lifetime testing of an adhesively bonded sample. By exploiting the characteristics of the Eigen frequencies of a purposely designed sample, a crack propagates in a controlled manner under the cyclic loading: as the crack propagates, the Eigen frequency departs from the excitation frequency and the load decreases...
The development of algorithms and models to be used for prediction of the reliability and health monitoring of components and sensors is of great importance in aerospace, automotive and power generation industry. For this purpose metamodels have been developed that are based on physical simulations and that are able to quantify the impact of uncertainties on system behavior. These surrogate metamodels...
As being used in a phosphor converted white LED (pc-white LED), the phosphor powders are always mixed with silicone for the color conversion of LED blue chip. Therefore, phosphor dispersion in the phosphor/silicone composite is regarded as a critical factor for optical characteristics of pc-white LEDs. In this paper, effects of the phosphor dispersion on the spectra, luminous efficacies and color...
In this paper a complete Multiphysics modelling via the Finite Element Method (FEM) of an air-coupled Piezoelectric Micromachined Ultrasonic Transducer (PMUT) is described, with its experimental validation related to the mechanical and acoustic responses.
This paper presents results of FEM Simulation and a statistical analysis for cracks in Multilayer Ceramic Capacitors (MLCCs). The main objective of the analysis is to validate the results of bending experiments on MLCCs and mainly the influence of solder type on fracture susceptibility and fracture form in ceramic body. The model also considers the prestresses occurring in the capacitor during firing...
As one of challenges, clip design for bonding area is becoming smaller and smaller to achieve die size requirement, better view inspection and efficient solder flux cleaning. However, with a small bonding area, there will be a concern on high thermal resistance during working condition, especially under a surge current, in which junction temperature may be higher than the melting temperature of soft...
This paper demonstrates, based on a practical example of a test hybrid circuit, the importance of proper modeling of the heat transfer coefficient dependence on the surface temperature rise and fluid velocity in air cooled electronic systems. Hybrid circuits usually have large surface area and consequently important temperature gradients could occur in them, hence the local values of the heat transfer...
This paper presents results of flex cracking experiments on Multilayer Ceramic Capacitors (MLCCs). The influence of solder fillet height, solder type and MLCC dimensions on the crack susceptibility of the component has been investigated. Subsequent statistical and metallographic analyses were carried out for more understanding of the failure mechanism. The statistical results show that the solder...
Stitch crack is a recurring failure mechanism for many years in semiconductor packaging. Currently, the combination of highly filled mold compounds, and copper wire increases the risk for stitch cracks after temperature cycling (TC). Firstly, highly filled mold compounds generally have a Coefficient of Thermal Expansion (CTE) that is much lower than that of copper, and a much higher elastic modulus...
Traditional lighting is focused on the prevention of hardware failures. With the trend towards controlled and connected systems, other components will start playing an equal role in the reliability of it. Here reliability need to be replaced by availability and other modelling approaches are to be taken into account. System prognostics and health management is the next step to service the connected...
Silicon carbide MOSFETs coming from every manufacturer selling on the market have been simulated using models provided by the respective manufacturers. Simulation results have been compared to datasheet characteristics. Discrepancies were identified and their possible causes have been investigated. This has been complemented with an analysis of each model structure. For model improvement, several...
This paper proposes a nonlinear model and reports the current-voltage (I–V) characteristics of a thermally driven V-shaped MEMS actuator with a folded spring (FS) reference beam. The nonlinear lumped element model is developed using circuit elements with temperature-dependent material properties. In addition, it is shown experimentally that the Joule heating occurring across the polysilicon layer...
Quality factor of resonators has been one of the most important parameters because it determines sensitivity of the device, espacially in the case of vacuum-packaged MEMS resonators. Typical energy loss mechanisms of vacuum-packaged MEMS resonator are supporting loss and TED. Those mechanisms can be affected by package structure because the package structure consists of acoustic wave path as well...
This paper presents the modelling of a Micro-Opto-Mechanical Pressure Sensor (MOMPS) manufactured in a SiN integrated photonic platform. Implemented using a single wavelength Mach Zehnder Interferometer (MZI), it relies on a single readout detector that could be integrated directly on CMOS. Current photonic processes exhibit high residual stresses in the sensitive membrane. In this paper we will focus...
Silicon based pressure sensors often take advantage of piezo-resistive gages which are normally embedded by multiple silicon oxide and silicon nitride layers where gold lines form a Wheatstone bridge. As a result of manufacturing - stepwise deposition of multiple layers - significant layer residual stresses occur in the GPa range in tension and compression. But also anodic bonding of the silicon MEMS...
The study focused on the onset of plastic flow in various copper raw materials. The tested copper sheets varied by the way they were manufactured (e.g. electroplated, cold rolled), by post treatments (e.g. chromate coating) or by pre ageing. Tests were conducted at different temperatures (25°C, 60°C, 100°C, 150°C). The results show that the onset of plastic flow depends strongly on the manufacturing...
The aim of the study is to carrying out a series of experimental reliability tests for lead solder alloy Sn63Pb37 regarding to the so-called model of damage accumulation. In spite of Sn63Pb37 is prohibited in mostly cases by RoHS directive it is still used in lots of electronic devices which have influence on human life safety e.g. life-support machines, airplanes etc. That's why authors decided to...
The ability of Through Crackstop Via (TCV) to prevent cracks from propagation is compared to conventional crackstop using a novel systematic simulation methodology. The design of TCV is, then, optimized by varying the angle between the metal layers as well as the TCV width. The larger angle and width result in a better TCV. The improvement in the TCV saturates at a specific TCV width.
An electronic test module is designed in order to monitor field failures of board assembly interconnections while simultaneously measuring the environmental loading conditions. The test module is built-in on the ceiling of a daily driving bus. During operation, when the engine is on, daisy chain interconnections as well as temperature and accelerometer sensors are measured continuously. The purpose...
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