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Publications (10 of 33) Show all publications
Akbari, S., Lövberg, A., Tegehall, P.-E., Brinkfeldt, K. & Andersson, D. (2019). Effect of PCB cracks on thermal cycling reliability of passive microelectronic components with single-grained solder joints. Microelectronics and reliability, 93, 61-71
Open this publication in new window or tab >>Effect of PCB cracks on thermal cycling reliability of passive microelectronic components with single-grained solder joints
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2019 (English)In: Microelectronics and reliability, ISSN 0026-2714, E-ISSN 1872-941X, Vol. 93, p. 61-71Article in journal (Refereed) Published
Abstract [en]

Lead-free tin-based solder joints often have a single-grained structure with random orientation and highly anisotropic properties. These alloys are typically stiffer than lead-based solders, hence transfer more stress to printed circuit boards (PCBs) during thermal cycling. This may lead to cracking of the PCB laminate close to the solder joints, which could increase the PCB flexibility, alleviate strain on the solder joints, and thereby enhance the solder fatigue life. If this happens during accelerated thermal cycling it may result in overestimating the lifetime of solder joints in field conditions. In this study, the grain structure of SAC305 solder joints connecting ceramic resistors to PCBs was studied using polarized light microscopy and was found to be mostly single-grained. After thermal cycling, cracks were observed in the PCB under the solder joints. These cracks were likely formed at the early stages of thermal cycling prior to damage initiation in the solder. A finite element model incorporating temperature-dependant anisotropic thermal and mechanical properties of single-grained solder joints is developed to study these observations in detail. The model is able to predict the location of damage initiation in the PCB and the solder joints of ceramic resistors with reasonable accuracy. It also shows that the PCB cracks of even very small lengths may significantly reduce accumulated creep strain and creep work in the solder joints. The proposed model is also able to evaluate the influence of solder anisotropy on damage evolution in the neighbouring (opposite) solder joints of a ceramic resistor.

Keywords
Anisotropy of tin grains, Finite element modelling, Lead-free soldering, Passive components, PCB cracking, Anisotropy, Ceramic materials, Cracks, Creep, Electronics packaging, Finite element method, Mechanical properties, Microelectronics, Printed circuit boards, Resistors, Soldering, Thermal cycling, Accelerated thermal cycling, Microelectronic components, Printed circuit board (PCBs), Thermal and mechanical properties, Thermal cycling reliability, Lead-free solders
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-37331 (URN)10.1016/j.microrel.2019.01.006 (DOI)2-s2.0-85059773183 (Scopus ID)
Note

 Funding details: VINNOVA, 2015-01420; Funding details: Swedish Insitute, SI; Funding text 1: This work has been conducted within the Swedish national project "Requirements, specification and verification of environmental protection and life of solder joints to components" supported by the Swedish Governmental Agency for Innovation Systems (Vinnova) under contract 2015-01420 .

Available from: 2019-01-22 Created: 2019-01-22 Last updated: 2019-01-22Bibliographically approved
Brinkfeldt, K., Wetter, G., Lövberg, A., Andersson, D., Toth-Pal, Z., Forslund, M. & Shisha, S. (2018). Failure mechanism assessment of TO-247 packaged SiC power devices. In: ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2018: . Paper presented at ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2018, 27 August 2018 through 30 August 2018. , Article ID V001T04A016.
Open this publication in new window or tab >>Failure mechanism assessment of TO-247 packaged SiC power devices
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2018 (English)In: ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2018, 2018, article id V001T04A016Conference paper, Published paper (Refereed)
Abstract [en]

As the automotive industry shifts towards the electrification of drive trains, the efficiency of power electronics becomes more important. The use of silicon carbide (SiC) devices in power electronics has shown several benefits in efficiency, blocking voltage and high temperature operation. In addition, the ability of SiC to operate at higher frequencies due to lower switching losses can result in reduced weight and volume of the system, which also are important factors in vehicles. However, the reliability of packaged SiC devices is not yet fully assessed. Previous work has predicted that the different material properties of SiC compared to Si could have a large influence on the failure mechanisms and reliability. For example, the much higher elastic modulus of SiC compared to Si could increase strain on neighboring materials during power cycling. In this work, the failure mechanisms of packaged Si- and SiC-based power devices have been investigated following power cycling tests. The packaged devices were actively cycled in 4.5 s heating and 20 s cooling at ΔT = 60 - 80 K. A failure analysis using micro-focus X-ray and scanning acoustic microscopy (SAM) was carried out in order to determine the most important failure mechanisms. The results of the analysis indicate that the dominant failure mechanism is wire bond liftoff at the device chip for all of the SiC-based devices. Further analysis is required to determine the exact failure mechanisms of the analyzed Si-based devices. In addition, the SiC-based devices failed before the Si-based devices, which could be a result of the different properties of the SiC material.

Keywords
Automotive industry, Efficiency, Electric railroads, Electronics industry, Electronics packaging, Failure (mechanical), High temperature operations, Microsystems, Outages, Silicon carbide, Blocking voltage, Failure mechanism, Higher frequencies, Lower switching loss, Power cycling tests, Scanning Acoustic Microscopy, Si-based devices, Silicon carbides (SiC), Power semiconductor devices
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-37000 (URN)10.1115/IPACK2018-8385 (DOI)2-s2.0-85057279573 (Scopus ID)9780791851920 (ISBN)
Conference
ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2018, 27 August 2018 through 30 August 2018
Note

 Funding details: Energimyndigheten, 2017-001699;

Available from: 2019-01-08 Created: 2019-01-08 Last updated: 2019-01-08Bibliographically approved
Brinkfeldt, K., Wetter, G., Lövberg, A., Tegehall, P.-E., Andersson, D., Goncalves, J., . . . Kwarnmark, M. (2018). Feasibility of PCB-integrated vibration sensors for condition monitoring of electronic systems. In: ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2018: . Paper presented at ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2018, 27 August 2018 through 30 August 2018.
Open this publication in new window or tab >>Feasibility of PCB-integrated vibration sensors for condition monitoring of electronic systems
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2018 (English)In: ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2018, 2018Conference paper, Published paper (Refereed)
Abstract [en]

The increasing complexity of electronics in systems used in safety critical applications, such as for example self-driving vehicles requires new methods to assure the hardware reliability of the electronic assemblies. Prognostics and Health Management (PHM) that uses a combination of data-driven and Physics-of-Failure models is a promising approach to avoid unexpected failures in the field. However, to enable PHM based partly on Physics-of-Failure models, sensor data that measures the relevant environment loads to which the electronics is subjected during its mission life are required. In this work, the feasibility to manufacture and use integrated sensors in the inner layers of a printed circuit board (PCB) as mission load indicators measuring impacts and vibrations has been investigated. A four-layered PCB was designed in which piezoelectric sensors based on polyvinylidenefluoride-co-trifluoroethylene (PVDF-TrFE) were printed on one of the laminate layers before the lamination process. Manufacturing of the PCB was followed by the assembly of components consisting of BGAs and QFN packages in a standard production reflow soldering process. Tests to ensure that the functionality of the sensor material was unaffected by the soldering process were performed. Results showed a yield of approximately 30 % of the sensors after the reflow soldering process. The yield was also dependent on sensor placement and possibly shape. Optimization of the sensor design and placement is expected to bring the yield to 50 % or better. The sensors responded as expected to impact tests. Delamination areas were present in the test PCBs, which requires further investigation. The delamination does not seem to be due to the presence of embedded sensors alone but rather the result of a combination of several factors. The conclusion of this work is that it is feasible to embed piezoelectric sensors in the layers of a PCB.

Keywords
Automobile electronic equipment, Automobile manufacture, Condition monitoring, Electric sensing devices, Integrated circuit manufacture, Microsystems, Piezoelectric devices, Piezoelectric transducers, Piezoelectricity, Printed circuit manufacture, Safety engineering, Soldering, Electronic assemblies, Physics of failure models, Piezoelectric sensors, Polyvinylidene fluorides, Printed circuit boards (PCB), Prognostics and health managements, Safety critical applications, Self-driving vehicles, Printed circuit boards
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-36610 (URN)10.1115/IPACK2018-8386 (DOI)2-s2.0-85057248348 (Scopus ID)9780791851920 (ISBN)
Conference
ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2018, 27 August 2018 through 30 August 2018
Available from: 2018-12-06 Created: 2018-12-06 Last updated: 2018-12-21Bibliographically approved
Lövberg, A., Tegehall, P.-E., Akbari, S. & Andersson, D. (2018). On the formation and propagation of laminate cracks and their influence on the fatigue lives of solder joints. In: 2018 19th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2018: . Paper presented at 19th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2018, 15 April 2018 through 18 April 2018 (pp. 1-13).
Open this publication in new window or tab >>On the formation and propagation of laminate cracks and their influence on the fatigue lives of solder joints
2018 (English)In: 2018 19th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2018, 2018, p. 1-13Conference paper, Published paper (Refereed)
Abstract [en]

Lead-free solder joints have been shown to increase the risk for crack formation in the PCB laminate under the solder pads. As such cracks propagate during thermal cycling, they decrease the strain imposed on the solderjoint by acting as strain relief. In accelerated thermal cycling, these joints have been found to remain virtually undamaged even after a very high number of cycles. If these cracks do not form or propagate to the same extent under milder cycling conditions, typical of service conditions, it may lead to an overestimation of the fatigue life of the solder joints in accelerated testing. In this work, the extent of strain relief and the influence of grain orientations on the initiation and propagation of these cracks are investigated through FE-modelling and compared to what has been experimentally observed for cross-sections of solder joints moulded in epoxy resin with added fluorescent agent and inspected using UV-light and electron backscatter diffraction. Due to the strong anisotropy of lead-free solder joints, the stress transferred to the laminate will vary significantly depending on grain orientation. The presence of these laminate cracks adds another layer of uncertainty to the already complex SnAgCu system, where the strong effects of anisotropy, the continuously evolving secondary precipitate coarsening and its interaction with the recrystallisation process govern the damage evolution. If these effects are not properly accounted for, the interpretation of thermal cycling or modelling and simulation results may be strongly misleading.

National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34020 (URN)10.1109/EuroSimE.2018.8369923 (DOI)2-s2.0-85048886876 (Scopus ID)9781538623596 (ISBN)
Conference
19th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2018, 15 April 2018 through 18 April 2018
Available from: 2018-07-04 Created: 2018-07-04 Last updated: 2018-08-20Bibliographically approved
Karlsson, H., Lidström, O., Grönqvist, H., Andersson, D., Wipenmyr, J. & Hernandez, N. (2018). Quality assurance of encapsulation architecture, including subsequent washing process for permanently mounted wearable sensors. In: 2018 IMAPS Nordic Conference on Microelectronics Packaging (NordPac): . Paper presented at 2018 IMAPS Nordic Conference on Microelectronics Packaging (NordPac) (pp. 14-23).
Open this publication in new window or tab >>Quality assurance of encapsulation architecture, including subsequent washing process for permanently mounted wearable sensors
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2018 (English)In: 2018 IMAPS Nordic Conference on Microelectronics Packaging (NordPac), 2018, p. 14-23Conference paper, Published paper (Refereed)
Abstract [en]

The overall objective of the project wearITmed, Wearable sensors in smart textiles, is to develop a novel wearable sensor system demonstrator. This sensor system aims to monitor symptoms of neurological disorders such as epilepsy, Parkinson’s disease and stroke. The wearable sensor system demonstrator, including both integrated gyros/accelerometers and textile sensors, is useful for the evaluation of clinically relevant movement patterns and other physiological parameters, and further to establish disease discriminating and treatment responsive objective variables. The work presented in this paper is focused on ensuring that the wearable sensor system can be cleaned and washed without first removing the electronics. The work includes three main areas; the adhesion and architecture, the molding and finally the washing test performance. Standard wettability and peel tests (Volvo Standard STD 185–0001) were performed on standard test board IPC-B-5 and IPC-9202 test vehicle for selecting the best adhesive and encapsulation materials in form of an epoxy (Epotek 302–3M) and a medical approved silicone (Nusil MED-6019). The molded components were washtested (Standard SS-EN ISO 6330:2012) followed by testing of the electrical resistance (Standard IPC-9202). As a result a total of 22 garments were produced with four individually mounted boards in each garment. The tests showed that the wearable sensors passed the washing tests and were still functional after 10 repeated washing cycles without any change or degradation in resistance or sign of electrical failure. The wearable electronics therefore meets the requirements of being simultaneously resistant to; water, temperature (40 °C), chemical detergents and dynamic forces.

Keywords
Adhesives, Biomedical monitoring, Wearable sensors, Encapsulation, Standards, Optical surface waves, Surface treatment, smart textiles, washability, adhesive bonding, potting and molding
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34341 (URN)10.23919/NORDPAC.2018.8423849 (DOI)2-s2.0-85051474502 (Scopus ID)
Conference
2018 IMAPS Nordic Conference on Microelectronics Packaging (NordPac)
Available from: 2018-08-06 Created: 2018-08-06 Last updated: 2019-03-06Bibliographically approved
Andersson, D., Grönqvist, H., Mayora, K., Tijero, M., Voirin, G., Steinke, A., . . . Weiler, P. (2018). Smart access to small lot manufacturing for systems integration. In: 2018 Pan Pacific Microelectronics Symposium, Pan Pacific 2018: . Paper presented at 2018 Pan Pacific Microelectronics Symposium, Pan Pacific 2018, 5 February 2018 through 8 February 2018 (pp. 1-9).
Open this publication in new window or tab >>Smart access to small lot manufacturing for systems integration
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2018 (English)In: 2018 Pan Pacific Microelectronics Symposium, Pan Pacific 2018, 2018, p. 1-9Conference paper, Published paper (Refereed)
Abstract [en]

The three year EU project SMARTER-SI that ends in January 2018 has tested a new concept for small lot manufacturing for SMEs which we call the Cooperative Foundry Model (CFM). During previous research, all RTOs have completed building blocks, i.e. components or parts of systems which are readily available and characterized by their high Technology Readiness Level (TRL). These building blocks are combined and integrated in so-called Application Experiments (AEs), thereby creating innovative Smart Systems that serve the SMEs' needs. Four pre defined AEs have been presented before [1] and in this paper, six additional AEs will be presented: i) a smart sensor for pneumatic combined clutch and brakes, ii) smart well plates for tissue engineering integrating continuous, non-invasive TEER iii) microclimate sensor for moisture applications, iv) LTCC-Si-Pressure Sensor, v) miniaturized capillary electrophoresis system for bio analysis, and vi) a MEMS sensor module for respiratory applications. Finally, a brief description of ongoing standardization efforts is presented.

Keywords
Cooperative Foundry Model, Prototyping, Small lot manufacturing, Smart Systems Integration, SSI, Standardization, Capillary electrophoresis, Foundries, Manufacture, Microelectronics, Software prototyping, Tissue engineering, Building blockes, Foundry model, High technology, MEMS sensors, Respiratory applications, Small-lot manufacturing, Smart systems integrations, Systems integration, Moisture control
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34530 (URN)10.23919/PanPacific.2018.8319009 (DOI)2-s2.0-85050778785 (Scopus ID)9781944543044 (ISBN)
Conference
2018 Pan Pacific Microelectronics Symposium, Pan Pacific 2018, 5 February 2018 through 8 February 2018
Available from: 2018-08-09 Created: 2018-08-09 Last updated: 2019-03-06Bibliographically approved
Weiler, P., Steinke, A., Andersson, D. & Lanting, C. J. M. (2018). Standardisation of smart systems building blocks: A requirement for a globally competitive cooperative foundry. In: : . Paper presented at Conference of Smart Systems Integration 2018 - 12th International Conference and Exhibition on Integration Issues of Miniaturized Systems ; Conference Date: 11 April 2018 Through 12 April 2018; Conference Code:138405 (pp. 181-188). Mesago Messe Frankfurt GmbH
Open this publication in new window or tab >>Standardisation of smart systems building blocks: A requirement for a globally competitive cooperative foundry
2018 (English)Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Mesago Messe Frankfurt GmbH, 2018
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:ri:diva-35554 (URN)2-s2.0-85054839412 (Scopus ID)
Conference
Conference of Smart Systems Integration 2018 - 12th International Conference and Exhibition on Integration Issues of Miniaturized Systems ; Conference Date: 11 April 2018 Through 12 April 2018; Conference Code:138405
Available from: 2018-11-02 Created: 2018-11-02 Last updated: 2019-01-08Bibliographically approved
Andersson, D., Tegehall, P.-E. & Wetter, G. (2018). The impact of conformal coatings on the environmental protection of PCBassemblies and the reliability of solder joints. In: : . Paper presented at 2018 IMAPS Nordic Conference on Microelectronics Packaging (NordPac), June 12-14, Oulu, Finland.
Open this publication in new window or tab >>The impact of conformal coatings on the environmental protection of PCBassemblies and the reliability of solder joints
2018 (English)Conference paper, Oral presentation only (Other academic)
National Category
Other Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34840 (URN)
Conference
2018 IMAPS Nordic Conference on Microelectronics Packaging (NordPac), June 12-14, Oulu, Finland
Available from: 2018-08-15 Created: 2018-08-15 Last updated: 2019-03-07Bibliographically approved
Lövberg, A., Tegehall, P.-E., Wetter, G., Brinkfeldt, K. & Andersson, D. (2017). Simulations of the impact of single-grained lead-free solder joints on the reliability of ball Grid Array components. In: : . Paper presented at EuroSimE 2017, 18th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems. Institute of Electrical and Electronics Engineers Inc., Article ID 7926289.
Open this publication in new window or tab >>Simulations of the impact of single-grained lead-free solder joints on the reliability of ball Grid Array components
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2017 (English)Conference paper, Published paper (Other academic)
Abstract [en]

The microstructure of lead-free solder joints often consists of only one or a few randomly oriented tin grains as a result of a large degree of undercooling during solidification. Due to the severe anisotropy of single crystal Sn and the random nature of the microstructure, the stress state and microstructural evolution of each joint will be unique.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers Inc., 2017
Keywords
Crystal microstructure, Lead-free solders, Microelectronics, Microstructure, Microsystems, Single crystals, Soldered joints, Tin, Undercooling, Lead-free solder joint, Stress state
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-30148 (URN)10.1109/EuroSimE.2017.7926289 (DOI)2-s2.0-85020212288 (Scopus ID)
Conference
EuroSimE 2017, 18th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems
Available from: 2017-07-31 Created: 2017-07-31 Last updated: 2019-03-08Bibliographically approved
Andersson, D., Weiler, P., Mayora, K., Kunze, M., Günzler, R., Karmann, S., . . . Smadja, R. (2017). SMARTER-SI - Smart access to manufacturing for Systems Integration. In: : . Paper presented at 2017 IMAPS Nordic Conference on Microelectronics Packaging (NordPac) 18–20 June, Gothenburg, Sweden (pp. 22-30).
Open this publication in new window or tab >>SMARTER-SI - Smart access to manufacturing for Systems Integration
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2017 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

The three year EU project SMARTER-SI that started in February 2015 has developed and tested a new production platform for smart systems that offer SMEs and “mid-cap” companies help to manufacture small and medium volumes. The ultimate goal of this project is to test a new concept for small lot production, which we call the Cooperative Foundry Model (CFM). The CFM is tested by combining components or parts of systems (building blocks) already developed by the RTOs involved in the project in so-called Application Experiments (AEs), thereby creating innovative Smart Systems which serve SMEs' product needs. During the first two years, four predefined AEs have been developed that consist of i) a multi-parametric point of care testing (POCT) device, ii) a dew-point measurement system, iii) a CO2 measurement system, and iv) a portable device that can be used to screen water quality.

Keywords
prototyping, Small lot manufacturing, Smart systems
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-31213 (URN)10.1109/NORDPAC.2017.7993157 (DOI)2-s2.0-85028609262 (Scopus ID)
Conference
2017 IMAPS Nordic Conference on Microelectronics Packaging (NordPac) 18–20 June, Gothenburg, Sweden
Available from: 2017-08-30 Created: 2017-08-30 Last updated: 2019-03-11Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-2232-7835

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