Thermal stability analysis of passive components embedded into printed circuit boards

Circuit World ◽  
2018 ◽  
Vol 44 (1) ◽  
pp. 29-36
Author(s):  
Wojciech Stęplewski ◽  
Andrzej Dziedzic ◽  
Kamil Janeczek ◽  
Aneta Araźna ◽  
Krzysztof Lipiec ◽  
...  

Purpose The purpose of this paper is to investigate the behavior of embedded passives under changing temperature conditions. Influence of different temperature changes on the basic properties of embedded passives was analyzed. The main reason for these investigations was to determine functionality of passives for space application. Design/methodology/approach The investigations were based on the thin-film resistors made of Ni-P alloy, thick-film resistors made of carbon or carbon-silver inks, embedded capacitors made of FaradFlex materials and embedded inductor made in various configurations. Prepared samples were examined under the influence of a constant elevated temperature (100, 130 or 160°C) in a long period of time (minimum of 30 h), thermal cycles (from −40 to +85°C) or thermal shocks (from −40 to +105°C or from −40 to +125°C). Findings The achieved results revealed that resistance drift became bigger when the samples were treated at a higher constant temperature. At the same time, no significant difference in change in electrical properties for 50 and 100 Ω resistors was noticed. For all the tests, resistance change was below 2 per cent regardless of a value of the tested resistors. Conducted thermal shock studies indicate that thin-film resistors, coils and some thick-film resistors are characterized by minor variations in basic parameters. Some of the inks may show considerable resistance variations with temperature changes. Significant changes were also exhibited by embedded capacitors. Originality/value The knowledge about the behavior of the operating parameters of embedded components considering environmental conditions allow for development of more complex systems with integrated printed circuit boards.

Circuit World ◽  
2017 ◽  
Vol 43 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Wojciech Steplewski ◽  
Andrzej Dziedzic ◽  
Janusz Borecki ◽  
Tomasz Serzysko

Purpose The purpose of this paper is to investigate the basic functional parameters of passive embedded components in printed circuit boards (PCBs) under environmental exposures such as thermal-humidity and thermal exposure. Design/methodology/approach The investigations were based on the thin-film resistors made of NiP alloy, thick-film resistors made of carbon or carbon–silver inks, embedded capacitors made of FaradFlex materials and embedded inductor made in various configurations. The capacitors and thin- and thick-film resistors were tested in the climatic chamber in conditions of thermal-humidity exposure at 85°C and 85 per cent RH for 500 h. The embedded inductors were tested in two different environmental conditions: thermal-humidity exposure at 60°C and 95 per cent RH, and thermal exposure at 150°C and additionally at the temperature in the range of +25°C to +150°C. Findings Studies show that in the case of embedded capacitors, the changes caused by exposure to thermal-humidity are durable and lead to the capacity increase. The embedded thin-film resistors behave in the same manner, whereas the thick-film resistors were the least resistant to the conditions of exposure. Most of the polymer thick-film resistors have been damaged. The changes of coils' properties during aging are small, and what is most important is that, after some time of exposure, their parameters stabilize at a particular level. The changes resulting from the increase in temperature are typically related to the change of material resistance (Cu) of which coils are made, and as such, they cannot be avoided but they can be predicted. Research limitations/implications The realized studies allowed determination of the properties of the embedded passive elements with respect to specific environmental exposures. The studies show that embedded resistors can be used interchangeably with chip passive elements. It allows saving the area on the surface of PCB, occupied by these passive elements, for assembly of active elements integrated circuits (ICs) and thus enabling the miniaturization of electronic devices. Originality/value The knowledge about the behavior of the operating parameters of embedded components, considering the environmental conditions, allows for development of more complex systems with integrated PCBs.


Circuit World ◽  
2014 ◽  
Vol 40 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Wojciech Steplewski ◽  
Andrzej Dziedzic ◽  
Janusz Borecki ◽  
Grazyna Koziol ◽  
Tomasz Serzysko

Purpose – The purpose of this paper is to investigate the influence of parameters of embedded resistive elements manufacturing process as well as the influence of environmental factors on their electrical resistance. The investigations were made in comparison to the similar constructions of discrete chip resistors assembled to standard printed circuit boards (PCBs). Design/methodology/approach – The investigations were based on the thin-film resistors made of NiP alloy, thick-film resistors made of carbon or carbon-silver inks as well as chip resistors in 0402 and 0603 packages. The polymer thick-film resistive films were screen-printed on the several types finishing materials of contact terminations such as copper, silver, and gold. To determine the sensitivity of embedded resistors versus standard assembled chip resistors on environmental exposure, the climatic chamber was used. The measurements of resistance were carried out periodically during the tests, and after the exposure cycles. Findings – The results show that the change of electrical resistance of embedded resistors, in dependence of construction and base material, is different and mainly not exceed the range of 3 per cent. The achieved results in reference to thin-film resistors are comparable with results for standard chip resistors. However, the results that were obtained for thick-film resistors with Ag and Ni/Au contacts are similar. It was not found the big differences between resistors with and without conformal coating. Research limitations/implications – The studies show that embedded resistors can be used interchangeably with chip resistors. It allows to save the area on the surface of PCB, occupied by these passive elements, for assembly of active elements (ICs) and thus enable to miniaturization of electronic devices. But embedding of passive elements into PCB requires to tackle the effect of each forming process steps on the operational properties. Originality/value – The technique of passive elements embedding into PCB is generally known; however, there are no detailed reports on the impact of individual process steps and environmental conditions on the stability of their electrical resistance. The studies allow to understand the importance of each factor process and the mechanisms of operational properties changes depending on the used materials.


Circuit World ◽  
2015 ◽  
Vol 41 (3) ◽  
pp. 125-132 ◽  
Author(s):  
Wojciech Stęplewski ◽  
Andrzej Dziedzic ◽  
Adam Kłossowicz ◽  
Paweł Winiarski ◽  
Janusz Borecki ◽  
...  

Purpose – This paper aims to report the investigations of capacitors and inductors embedded into printed circuit boards (PCBs) designed in various layouts. Design/methodology/approach – The research were focused on the components embedded into four-layer PCBs with different structures of the inner layers. Three special capacitive laminates for manufacturing of thin-film embedded capacitors and several types of coils in the form of a spiral, meander and solenoid are described. In addition, a part of the spiral-type coils was formed with an aperture in the center in which the magnetic core, made of soft magnetic composites’ material was placed to increase the coil inductance. Findings – Various constructions of embedded capacitors and coils were designed and manufactured. Capacitance and loss tangent of capacitors to determine the repeatability of the production process were determined. Capacitor’s long-term stability analysis was performed by exposing test samples to elevated temperatures (70, 100 or 130°C), realized with the aid of heating plate, for at least 160 h. The temperature characteristics for the capacitance and loss tangent from 15 to 100°C were determined. Also the induction of different designs and layouts coils was determined. Originality/value – The wide parameters’ characterization of capacitors and coils embedded into PCBs allow the analysis of their properties with regard to their practical application. The promising results of the realized measurements show that the capacitors and induction coils with studied structures can be widely used in the construction of embedded circuits into PCBs (e.g. filters, radio frequency identification systems and generators).


2013 ◽  
Vol 61 (3) ◽  
pp. 731-735
Author(s):  
A.W. Stadler ◽  
Z. Zawiślak ◽  
W. Stęplewski ◽  
A. Dziedzic

Abstract. Noise studies of planar thin-film Ni-P resistors made in/on Printed Circuit Boards, both covered with two different types of cladding or uncladded have been described. The resistors have been made of the resistive-conductive-material (Ohmega-Ply©) of 100 Ώ/sq. Noise of the selected pairs of samples has been measured in the DC resistance bridge with a transformer as the first stage in a signal path. 1/f noise caused by resistance fluctuations has been found to be the main noise component. Parameters describing noise properties of the resistors have been calculated and then compared with the parameters of other previously studied thin- and thick-film resistive materials.


Circuit World ◽  
2015 ◽  
Vol 41 (3) ◽  
pp. 121-124
Author(s):  
Wojciech Stęplewski ◽  
Mateusz Mroczkowski ◽  
Radoslav Darakchiev ◽  
Konrad Futera ◽  
Grażyna Kozioł

Purpose – The purpose of this study was the use of embedded components technology and innovative concepts of the printed circuit board (PCB) for electronic modules containing field-programmable gate array (FPGA) devices with a large number of pins (e.g. Virtex 6, FF1156/RF1156 package, 1,156 pins). Design/methodology/approach – In the multi-layered boards, embedded passive components that support FPGA device input/output (I/O), such as blocking capacitors and pull-up resistors, were used. These modules can be used in rapid design of electronic devices. In the study, the MC16T FaradFlex material was used for the inner capacitive layer. The Ohmega-Ply RCM 25 Ω/sq material was used to manufacture pull-up resistors for high-frequency pins. The embedded components have been connected to pins of the FPGA component by using plated-through holes for capacitors and blind vias for resistors. Also, a technique for a board-to-board joining, by using castellated terminations, is described. Findings – The fully functional modules for assembly of the FPGA were manufactured. Achieved resistance of embedded micro resistors, as small as the smallest currently used surface-mount device components (01005), was below required tolerance of 10 per cent. Obtained tolerance of capacitors was less than 3 per cent. Use of embedded components allowed to replace the pull-up resistors and blocking capacitors and shortens the signal path from the I/O of the FPGA. Correct connection to the castellated terminations with a very small pitch was also obtained. This allows in further planned studies to create a full signal distribution system from the FPGA without the use of unreliable plug connectors in aviation and space technology. Originality/value – This study developed and manufactured several innovative concepts of signal distribution from printed circuit boards. The signal distribution solutions were integrated with embedded components, which allowed for significant reduction in the signal path. This study allows us to build the target object that is the module for rapid design of the FPGA device. Usage of a pre-designed module would lessen the time needed to develop a FPGA-based device, as a significant part of the necessary work (mainly designing the signal and power fan-out) will already be done during the module development.


Circuit World ◽  
2015 ◽  
Vol 41 (2) ◽  
pp. 76-79
Author(s):  
Boleslav Psota ◽  
Alexandr Otáhal ◽  
Ivan Szendiuch

Purpose – The main aim of this paper is to investigate the influence of the cavity coverage on the printed circuit boards (PCB) to the resonant frequency, acceleration and displacement. Design/methodology/approach – Tests were realized on four PCBs with different cavity areas. Frequency range of tests was between 10 and 2,000 Hz with 0.3 g acceleration amplitude. In addition, more simulations were performed to check different setups of the boards. Findings – From the calculated and measured data, it is clear that with the larger cavity area the resonance frequency drops. In case a greater number of components placed in cavities are needed on board, it is appropriate to use multiple smaller cavities than the bigger ones. Originality/value – Results in this paper could be very useful for PCB manufacturers and designers during designing of the new PCBs with cavities for dipped components.


2017 ◽  
Vol 29 (1) ◽  
pp. 54-58 ◽  
Author(s):  
Andrzej Dziedzic ◽  
Pawel Osypiuk ◽  
Wojciech Steplewski

Purpose The paper aims to verify the influence of mechanical factors (longitudinal elongation at constant stretching velocity, constant elongation strain and cyclic compressive and tensile stresses) on the electrical properties of thin-film and polymer thick-film resistors on flexible substrates. Design/methodology/approach Kapton foil was used as a substrate for all test samples. Designed resistive structures were made with the aid of two polymer thick-film resistive inks or OhmegaPly Ni-P resistive foil. Two different topologies – the horseshoe and triangular – were used. These topologies should have the opposite stability parameters. Findings Almost all presented data confirm the influence of the topology of resistors on stability of their electrical properties. The resistive materials applied for test structures also affect the stability under various mechanical exposures. Originality/value In general, the largest changes were caused by longitudinal elongation at constant stretching velocity, whereas other tests caused smaller changes of electrical properties. The measurements confirm the influence of topology on stability of electric properties.


Circuit World ◽  
2017 ◽  
Vol 43 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Aneta Arazna ◽  
Kamil Janeczek ◽  
Konrad Futera

Purpose This paper aims to present the results of investigations of inkjet-printed electronic circuits fabricated on a flexible substrate (KAPTON foil) using silver nanoparticles ink. Design/methodology/approach Fully inkjet-printed conductive circuit tracks were printed on a flexible, transparent KAPTON foil, using a commercial 40LT-15 C nanosilver ink as well as a PixDro LP50 inkjet printer with KonicaMinnolta 512 printhead. After cure, electrical properties by resistance measurements and printing quality by optical and SEM microscopic observation of conductive tracks were examined. Afterwards, the tested samples were annealed for 1, 2 and 3 h at 150°C or subjected to cycling bending. Findings It was found that silver nanoparticles ink could be used for the preparation of electronic circuits using the inkjet printing technique. The obtained patterns had appropriate mapping and good quality. It was also noticed that thermal annealing caused a decrease in resistivity values of the tested lines irrespective of their width. Approximately 34 per cent decrease was achieved in the values of resistivity of all the tested lines after the first hour of thermal annealing. After the second hour, the values of resistivity decreased by another 50 per cent. There were no visible changes in resistivity values after 1,000 cycles of bending. Originality/value In this paper, the results of thermal annealing and bending tests of inkjet-printed silver nanoparticle conductive tracks on flexible substrate were presented. That is very important information for producing printed circuit boards using ecological, rapid and low-cost inkjet printing techniques, particularly during the production of printed circuit boards on flexible substrates working in different conditions of mechanical and thermal stresses.


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