Environmental tests of embedded thin- and thick-film resistors in comparison to chip resistors

Circuit World ◽  
2014 ◽  
Vol 40 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Wojciech Steplewski ◽  
Andrzej Dziedzic ◽  
Janusz Borecki ◽  
Grazyna Koziol ◽  
Tomasz Serzysko
Keyword(s):  
Thin Film ◽  
Thick Film ◽  
Electrical Resistance ◽  
Printed Circuit Boards ◽  
Base Material ◽  
Forming Process ◽  
Content Type ◽  
Thin Film Resistors ◽  
Embedded Resistors ◽  
The Impact

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.

Assessment of stability and reliability of embedded components in printed circuit boards

Circuit World ◽  
2017 ◽  
Vol 43 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Wojciech Steplewski ◽  
Andrzej Dziedzic ◽  
Janusz Borecki ◽  
Tomasz Serzysko
Keyword(s):  
Thin Film ◽  
Thick Film ◽  
Environmental Conditions ◽  
Printed Circuit Boards ◽  
Thermal Exposure ◽  
Circuit Boards ◽  
Content Type ◽  
Embedded Capacitors ◽  
Printed Circuit ◽  
Thin Film Resistors

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.

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 ◽  
...  
Keyword(s):  
Thin Film ◽  
Thick Film ◽  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Content Type ◽  
Temperature Changes ◽  
Embedded Capacitors ◽  
Printed Circuit ◽  
Embedded Passives ◽  
Thin Film Resistors

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.

Stability of electrical properties for mechanically exposed thick- and thin-film resistors on flexible substrates

2017 ◽  
Vol 29 (1) ◽  
pp. 54-58 ◽  
Author(s):  
Andrzej Dziedzic ◽  
Pawel Osypiuk ◽  
Wojciech Steplewski
Keyword(s):  
Thin Film ◽  
Electrical Properties ◽  
Thick Film ◽  
Flexible Substrates ◽  
Stability Parameters ◽  
Content Type ◽  
Thin Film Resistors ◽  
Mechanical Factors ◽  
The Stability ◽  
Almost All

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.

scholarly journals Current Noise in Thick and Thin Film Resistors

1983 ◽  
Vol 10 (2-3) ◽  
pp. 81-85 ◽  
Author(s):  
S. Demolder ◽  
A. Van Calster ◽  
M. Vandendriessche
Keyword(s):  
Thin Film ◽  
Thick Film ◽  
Measured Data ◽  
Measuring Circuit ◽  
Current Noise ◽  
High Quality ◽  
Thin Film Resistors

In this paper a sensitive measuring circuit is described for the measurement of current noise on high quality thin and thick film resistors. Measured data on resistors are presented and analysed.

scholarly journals Investigation of reactively sputtered TaN thin-film resistors for microwave photonic applications

2021 ◽  
pp. 93-98
Author(s):  
Evgenii Erofeev ◽  
Egor Polyntsev ◽  
Sergei Ishutkin
Keyword(s):  
Thin Film ◽  
Thermal Stability ◽  
Magnetron Sputtering ◽  
Electrical Resistance ◽  
High Thermal Stability ◽  
Tantalum Nitride ◽  
Reactive Magnetron ◽  
Microwave Photonic ◽  
Thin Film Resistors ◽  
Thermal Stability Of

Electrophysical characteristics and their thermal stability of thin-film resistors based on tantalum nitride (TaN) obtained by reactive magnetron sputtering were investigated. The optimal modes of the magnetron sputtering process are determined, ensuring the Ta2N phase film composition with the value of the specific electrical resistance of 250 μm cm and high thermal stability of the parameters. On the basis of the investigations carried out, thin-film matching resistors were manufactured for use as part of an electro-optical InP-based MZ modulator

scholarly journals Morphology and acoustic artefacts of copper deposits electroplated using megasonic assisted agitation

Circuit World ◽  
2016 ◽  
Vol 42 (3) ◽  
pp. 127-140 ◽  
Author(s):  
Thomas D.A. Jones ◽  
David Flynn ◽  
Marc P.Y. Desmulliez ◽  
Dennis Price ◽  
Matthew Beadel ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Printed Circuit Boards ◽  
Surface Acoustic Waves ◽  
Electrolyte Solutions ◽  
Acoustic Power ◽  
Circuit Boards ◽  
Content Type ◽  
Measuring Surface ◽  
Micro Bubble ◽  
The Impact

Purpose This study aims to understand the influence of megasonic (MS)-assisted agitation on printed circuit boards (PCBs) electroplated using copper (Cu) electrolyte solutions to improve plating efficiencies through enhanced ion transportation. Design/methodology/approach The impact of MS-assisted agitation on topographical properties of the electroplated surfaces was studied through a design of experiments by measuring surface roughness, which is characterised by values of the parameter Ra as measured by white light phase shifting interferometry and high-resolution scanning electron microscopy. Findings An increase in Ra from 400 to 760 nm after plating was recorded for an increase in acoustic power from 45 to 450 W. Roughening increased because of micro-bubble cavitation energy and was supported through direct imaging of the cavitation. Current thieving effect by the MS transducer induced low currents, leading to large Cu grain frosting and reduction in the board quality. Current thieving was negated in plating trials through specific placement of transducer. Wavy electroplated surfaces, due to surface acoustic waves, were also observed to reduce the uniformity of the deposit. Research limitations/implications The formation of unstable transient cavitation and variation of the topology of the Cu surface are unwanted phenomena. Further plating studies using MS agitation are needed, along with fundamental simulations, to determine how the effects can be reduced or prevented. Practical implications This study can help identify manufacturing settings required for high-quality MS-assisted plating and promote areas for further investigation, leading to the development of an MS plating manufacturing technique. Originality/value This study quantifies the topographical changes to a PCB surface in response to MS agitation and evidence for deposited Cu artefacts due to acoustic effects.

Piezoresistive effect in embedded thick-film resistors

Circuit World ◽  
2019 ◽  
Vol 45 (1) ◽  
pp. 31-36
Author(s):  
Janusz Borecki ◽  
Aneta Araźna ◽  
Kamil Janeczek ◽  
Jerzy Kalenik ◽  
Michał Kalenik ◽  
...  
Keyword(s):  
Thick Film ◽  
Electrical Resistance ◽  
Printed Electronics ◽  
Technological Development ◽  
Substrate Material ◽  
Piezoresistive Effect ◽  
Content Type ◽  
Sensor Applications ◽  
Potential Possibility ◽  
Applied Stresses

Purpose Nowadays, using of material properties for monitoring of phenomena occurring in the surrounding environment is very desirable. Taking into account the dynamic development of Internet of Things and the technological development of printed electronics, research into the using of printed electronic components for sensor applications can be one of the most prominent directions of searching for new innovative solutions. Among others, it is possible to apply them to produce the strain gauges, as well as for construction of advanced sensors for medical applications. The goal of this paper is to present the possibilities and using different constructions of embedded polymer thick-film resistors as the sensors of tension or strain. Design/methodology/approach The investigations were based on the polymer thick-film resistors made of carbon or carbon–silver inks printed on copper pads made on FR-4 material on two sides. The longitudinal samples laminated with resin-coated copper foil material and without lamination were bent on a strength machine. During the tests, the resistors depending on their placement were stretched or compressed. Some of the samples were also tested under high pressure. Under the influence of applied stresses, there was a reversible change in electrical resistance, which was monitored. Findings The study showed that the polymer thick-film resistors are characterized by a measurable piezoresistive effect. By analyzing the value of the observed resistance changes, a magnitude of strain or pressure can be worked out. During the bending, the piezoresistive effect depends on the location and orientation of the resistor. After stopping of the mechanical strains, the electrical resistance of the resistive elements does not return exactly to the initial value. This is probably related to the substrate material and the resistive paste composition. The results are very promising and further research will be done. Originality/value The results provided information about the piezoresistive effect of polymer thick-film resistors printed on the deformable substrate which could be interesting for engineers involved in printed sensor development dedicated for different fields of application. This phenomenon can be used to manufacturing cheap and uncomplicated sensors to monitor deformation. There are several aspects to be solved, but with the use of new types of resistive pastes and substrates, there is a potential possibility of using such resistors as sensors.

scholarly journals Estimation of fatigue life for clinched joints with the Local Strain Approach incorporating the impact of cold forming to cyclic material properties

2021 ◽  
Vol 349 ◽  
pp. 04005
Author(s):  
Boris Spak ◽  
Maximilian Schlicht ◽  
Karina Nowak ◽  
Markus Kästner ◽  
Pascal Froitzheim ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Material Properties ◽  
Lightweight Design ◽  
Base Material ◽  
Local Strain ◽  
Small Scale ◽  
Forming Process ◽  
Cold Forming ◽  
Finite Element Software ◽  
The Impact

Joining by forming is a commonly applied technique in the automotive industry to assemble parts of thin metal sheets to meet the demands of lightweight design. The joining operation induces changes in material behaviour due to cold forming, that can be observed in increased hardness in the area close to the joint neck compared to the base material. Complex geometrical features of clinched joints on a small scale and the lack of non-destructive methods to track local stresses and strains require a combined approach utilizing numerical and experimental techniques. Numerical process and loading simulation are performed utilizing commercial finite element software LS-Dyna®. Hardness measurements in the joint are carried out to assess the impact of forming operation. Cyclic material properties are derived from Vickers hardness to estimate fatigue life with the Local Strain Approach using the damage parameter PSWT. Fatigue life estimation with failure criterion crack initiation obtained from simulation results is compared to those from experiments. The results obtained indicate that the Local Strain Approach is suitable for fatigue life estimations of clinched joints under constant amplitude loading as long as the influence of the forming process is considered.

Electrical properties of thin-film resistors in a wide temperature range

Circuit World ◽  
2015 ◽  
Vol 41 (3) ◽  
pp. 116-120 ◽  
Author(s):  
Paweł Winiarski ◽  
Adam Kłossowicz ◽  
Jacek Wróblewski ◽  
Andrzej Dziedzic ◽  
Wojciech Stęplewski
Keyword(s):  
Thin Film ◽  
Electrical Properties ◽  
Low Temperature ◽  
Wide Temperature Range ◽  
Linear Temperature Dependence ◽  
Content Type ◽  
Temperature Range ◽  
Wide Range ◽  
Thin Film Resistors ◽  
Thermal Shocks

Purpose – The purpose of this paper is to characterize electrical properties of nickel-phosphorus (Ni-P) thin-film resistors made on FR-4 laminate in a wide range of temperature (from −180 to 20°C). Design/methodology/approach – The study was performed using resistors made of Ni-P foil with two different thicknesses (0.1 or 0.05 μm) and sheet resistances (100 or 250 Ω/sq), respectively. The resistance rectangular resistors had length and width from the range between 0.59 and 5.91 mm. The resistance versus temperature characteristics and their distribution as well as resistors ' durability to low-temperature thermal shocks were investigated. Findings – The results showed almost linear temperature dependence of resistance with a negative temperature coefficient of resistance of about −95 ppm/°C for 250 Ω/sq layer and −55 ppm/°C for 100 Ω/sq layer. A very small dimensional effect was observed for sheet resistance as well as for R(T) characteristic. Thin-film resistors are also characterized by very high durability to low-temperature thermal shocks. Originality/value – The results presented in this paper can be very useful for low-temperature applications of thin-film resistors made on printed circuit boards. They suggest possibility of wide applications of these components in a wide temperature range.

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