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In this paper new results are presented about our advances in the field of substituting the commonly used FR4 (fiberglass+epoxy) for environmentally friendly substrates in Printed Circuit Board (PCB) technology. Avoiding traditional FR4 substrate may help to reduce a significant part of the generated harmful e-waste. The investigations are based on previous results achieved at the department with...
ECM (electrochemical migration) is sort of short failure mechanism that can lead to series defect in case of loaded circuits, when moisture exist on/in a conductor-dielectric-conductor system. Water drop (WD) test and scanning electron microscopy — energy disperse spectroscopy (SEM-EDS) methods were used to investigate the ECM behavior on different Sn-Sb alloys and pure Sn was the reference. The results...
The impact of chloride ion concentration on electrochemical migration (ECM) of tin and silver was studied by using an in-situ optical and electrical inspection system. It was found, that in both cases, dendrites grow not only in an electrolyte solution at low chloride concentration but also in an electrolyte at medium and high or even saturated chloride concentrations as well. According to the results,...
Electroanalytical tests were carried out to investigate the corrosion behavior of various Pb-free solder alloys in NaCl bulk solution under room temperature. Scanning electron microscope (SEM) method was applied to investigate the corroded surface structure and corrosion depth using cross-sectional samples. Furthermore, energy dispersive spectroscopy (EDS) method was also applied to identify the elemental...
The effect of Na2SO4 concentration on electrochemical migration (ECM) of copper and tin was investigated applying an in-situ optical and real-time electrical inspection system. According to the Mean-Time-To-Failure (MTTF) values, the ECM susceptibility of copper has increased at low concentration levels. However, the ECM susceptibility of copper has decreased at the medium and stopped at the high...
The paper presents novel research results and progress report towards the production of functional, commercial electronics on biodegradable Printed Circuit Boards (PCB) via presenting the realization of an MP3 player on different eco-friendly substrates. With the production of commercial devices on such base boards, potential e-waste can be reduced. The omission of the traditional epoxy-based FR4...
Fuzzy systems have been successfully used in the area of controllers for a long time. The Mamdani method is one of the most popular inference systems for practical applications. The main problem of Mamdani-type inference system and other fuzzy logic based controllers is how to gain the fuzzy rules the inference system based on. Several approaches have been proposed for automatic rule base identification...
The fuzzy J-K and D flip-flops present s-shape transfer characteristics in same particular cases. We propose the fuzzy flip-flop neurons; single input-single output units derived from fuzzy flip-flops as sigmoid function generators. The fuzzy neurons-based neural networks, Fuzzy Flip-Flop Neural Networks (FNN) parameters are quasi optimized using a second-order gradient algorithm, the Levenberg-Marquardt...
The effect of sulphate ion concentration on electrochemical migration (ECM) of silver was investigated by applying an in-situ optical and electrical inspection system. It was found that dendrites grow not only in an electrolyte solution with low sulphate ion concentration but also in electrolytes with medium and high or even saturated sulphate ion concentrations. According to the Mean-Time-To-Failure...
The corrosion properties of different lead-free solder alloys (including novel low Ag content solder alloys) were investigated using the potentiodynamic polarization test method in 3.5 wt% NaCl solution. The results showed that most of the investigated lead-free micro-alloyed solders have better corrosion properties compared to the commonly used SAC305 lead-free solder alloy. The main causes of the...
The paper presents experimental research on investigating the production and testing aspects of ISO/IEC 14443 contactless RFID tags fabricated on biodegradable cellulose acetate (CA) biopolymer-based Printed Circuit Boards (PCB). Our approach reduces the harmful plastic waste by substituting the standard materials of the cards with biodegradable substrate. Also, with common PCB fabrication methodology...
The paper gives an overview of various bacterial type evolutionary algorithms used for fuzzy rule based identification. In order to find an optimal rule base from the input-output training data set, several improved algorithms have been developed in recent years. The task is to increase the models’ accuracy and convergence speeds by modifying a part of the Mamdani-type inference system.
The effect of NaCl crystals on water condensation and on electrochemical migration processes (ECM) were investigated in case of different lead bearing and lead-free solder alloys on FR4 substrate during a special Thermal-humidity Bias (THB) test, called dew point test. The dew point test simulated the water condensation process and ECM, which processes were followed by in-situ optically and simultaneously...
Water drop (WD) test and a contact angle measurement method were used to investigate the electrochemical migration (ECM) behavior on different microelectronic substrates with silver conductor lines in all cases. Environment friendly substrates were also investigated in this study as possible candidates of the conventional ones. ECM is kind of short failure phenomenon, which can lead to series defect...
The paper focuses on biodegradable Printed Circuit Boards (PCB) from the aspect of PCB fabrication technology and soldering. Different biodegradable Cellulose Acetate (CA) PCBs were used during the tests (one sided and two sided), and the possible application of pre-preg was also taken into account to improve pad adhesion on the base material. The surfaces of the boards were evaluated in order to...
Mamdani-type inference systems with trapezoidal-shaped fuzzy membership functions play a crucial role in a wide variety of engineering systems, including real-time control, transportation and logistics, network management, etc. The automatic identification or construction of such fuzzy systems input output data is one of the key problems in modeling. In the past years, the authors have investigated...
Electrochemical migration (ECM) behaviour investigations were carried out on “oxide-free” and highly oxidized copper surfaces in pure water. It was shown in our previous paper that the oxidation number of copper ion mainly depends on the oxide layer thickness of the copper surface; in the case of “oxide-free” copper surface the Cu1+ ions dominated, while Cu2+ ions were mainly formed in the case of...
In this paper we propose non-parametric t-norms such as algebraic, trigonometric and Hamacher product, furthermore parametric Hamacher t-norm in Mamdani type inference systems. Various models with trapezoidal shaped fuzzy membership function are applied in order to improve the efficiency of bacterial memetic algorithm in automatic fuzzy rule identification.
Contact angle measurements of water droplets were carried out on fiberglass epoxy resin and polyimide substrates related to water condensation effect as an antecedent process of electrochemical migration. It was shown in our previous paper that water condensation intensity depends mainly on the surface roughness (which determines capillary condensation) and on the heat diffusivity of the substrate...
The purpose of this paper is to present a new version of the Bacterial Algorithms used for fuzzy rule base extraction called Progressive Bacterial Algorithm. In order to explore high quality models with very good speed of convergence towards the optimal rule base, we develop an improved version of the Bacterial Evolutionary and former Bacterial Memetic Algorithms. It is shown, in case of multidimensional...
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