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Publications (10 of 58) Show all publications
Fan, X., Fredrik, F., Smith, A. D., Schröder, S., Wagner, S., Rödjegård, H., . . . Niklaus, F. (2019). Graphene ribbons with suspended masses as transducers in ultra-small nanoelectromechanical accelerometers. Nature Electronics, 2(9), 394-404
Open this publication in new window or tab >>Graphene ribbons with suspended masses as transducers in ultra-small nanoelectromechanical accelerometers
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2019 (English)In: Nature Electronics, ISSN 2520-1131, Vol. 2, no 9, p. 394-404Article in journal (Refereed) Published
Abstract [eo]

Nanoelectromechanical system (NEMS) sensors and actuators could be of use in the development of next-generation mobile, wearable and implantable devices. However, these NEMS devices require transducers that are ultra-small, sensitive and can be fabricated at low cost. Here, we show that suspended double-layer graphene ribbons with attached silicon proof masses can be used as combined spring–mass and piezoresistive transducers. The transducers, which are created using processes that are compatible with large-scale semiconductor manufacturing technologies, can yield NEMS accelerometers that occupy at least two orders of magnitude smaller die area than conventional state-of-the-art silicon accelerometers. With our devices, we also extract the Young’s modulus values of double-layer graphene and show that the graphene ribbons have significant built-in stresses.

Place, publisher, year, edition, pages
Nature Publishing Group, 2019
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-259517 (URN)10.1038/s41928-019-0287-1 (DOI)000486394600009 ()2-s2.0-85072131685 (Scopus ID)
Note

QC 20191004

Available from: 2019-09-16 Created: 2019-09-16 Last updated: 2019-10-14Bibliographically approved
Laakso, M. J., Bleiker, S. J., Liljeholm, J., Mårtensson, G. E., Asiatici, M., Fischer, A. C., . . . Niklaus, F. (2018). Through-Glass Vias for Glass Interposers and MEMS Packaging Applications Fabricated Using Magnetic Assembly of Microscale Metal Wires. IEEE Access, 6, 44306-44317
Open this publication in new window or tab >>Through-Glass Vias for Glass Interposers and MEMS Packaging Applications Fabricated Using Magnetic Assembly of Microscale Metal Wires
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2018 (English)In: IEEE Access, E-ISSN 2169-3536, Vol. 6, p. 44306-44317Article in journal (Refereed) Published
Abstract [en]

A through-glass via (TGV) provides a vertical electrical connection through a glass substrate. TGVs are used in advanced packaging solutions, such as glass interposers and wafer-level packaging of microelectromechanical systems (MEMS). However, TGVs are challenging to realize because via holes in glass typically do not have a sufficiently high-quality sidewall profile for super-conformal electroplating of metal into the via holes. To overcome this problem, we demonstrate here that the via holes can instead be filled by magnetically assembling metal wires into them. This method was used to produce TGVs with a typical resistance of 64 m Omega, which is comparable with other metal TGV types reported in the literature. In contrast to many TGV designs with a hollow center, the proposed TGVs can be more area efficient by allowing solder bump placement directly on top of the TGVs, which was demonstrated here using solder-paste jetting. The magnetic assembly process can be parallelized using an assembly robot, which was found to provide an opportunity for increased wafer-scale assembly speed. The aforementioned qualities of the magnetically assembled TGVs allow the realization of glass interposers and MEMS packages in different thicknesses without the drawbacks associated with the current TGV fabrication methods.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Keywords
Chip scale packaging, femtosecond laser, glass interposer, laser ablation, multichip modules, robotic assembly, self-assembly, spin-on glass, thermal expansion, through-glass via, through-silicon vias, TSV
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-235465 (URN)10.1109/ACCESS.2018.2861886 (DOI)000444505800001 ()2-s2.0-85050982480 (Scopus ID)
Funder
Knut and Alice Wallenberg FoundationVINNOVA, 324189Swedish Foundation for Strategic Research , GMT14-0071 RIF14-0017
Note

QC 20180928

Available from: 2018-09-28 Created: 2018-09-28 Last updated: 2018-10-02Bibliographically approved
Laakso, M., Bleiker, S. J., Liljeholm, J., Mårtensson, G., Asiatici, M., Fischer, A. C., . . . Niklaus, F. (2018). Through-Glass Vias for MEMS Packaging. In: : . Paper presented at The Micronano System Workshop (MSW), 2018, Helsinki, Finland, 13-15 May.
Open this publication in new window or tab >>Through-Glass Vias for MEMS Packaging
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2018 (English)Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

Novelty / Progress Claims We have developed a new method for fabrication of through-glass vias (TGVs). The method allows rapid filling of via holes with metal rods both in thin and thick glass substrates.

Background Vertical electrical feedthroughs in glass substrates, i.e. TGVs, are often required in wafer-scale packaging of MEMS that utilizes glass lids. The current methods of making TGVs have drawbacks that prevent the full utilization of the excellent properties of glass as a package material, e.g. low RF losses. Magnetic assembly has been used earlier to fabricate through-silicon vias (TSVs), and in this work we extend this method to realize TGVs [1].

Methods The entire TGV fabrication process is maskless, and the processes used include: direct patterning of wafer metallization using femtosecond laser ablation, magnetic-fieldassisted self-assembly of metal wires into via holes, and solder-paste jetting of bump bonds on TGVs.

Results We demonstrate that: (1) the magnetically assembled TGVs have a low resistance, which makes them suitable even for low-loss and high-current applications; (2) the magneticassembly process can be parallelized in order to increase the wafer-scale fabrication speed; (3) the magnetic assembly produces void-free metal filling for TGVs, which allows solder placement directly on top of the TGV for the purpose of high integration density; and (4) good thermal-expansion compatibility between TGV metals and glass substrates is possible with the right choice of materials, and several suitable metals-glass pairs are identified for possible improvement of package reliability [2].

[1] M. Laakso et al., IEEE 30th Int. Conf. on MEMS, 2017. DOI:10.1109/MEMSYS.2017.7863517

[2] M. Laakso et al., “Through-Glass Vias for Glass Interposers and MEMS Packaging Utilizing Magnetic Assembly of Microscale Metal Wires,” manuscript in preparatio

National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-238647 (URN)
Conference
The Micronano System Workshop (MSW), 2018, Helsinki, Finland, 13-15 May
Note

QC 20181106

Available from: 2018-11-06 Created: 2018-11-06 Last updated: 2019-05-17Bibliographically approved
Gao, J., Fischer, A. C., Svensson, P. H. & Kloo, L. (2017). Crystallography as Forensic Tool for Understanding Electrolyte Degradation in Dye-sensitized Solar Cells. CHEMISTRYSELECT, 2(4), 1675-1680
Open this publication in new window or tab >>Crystallography as Forensic Tool for Understanding Electrolyte Degradation in Dye-sensitized Solar Cells
2017 (English)In: CHEMISTRYSELECT, ISSN 2365-6549, Vol. 2, no 4, p. 1675-1680Article in journal (Refereed) Published
Abstract [en]

The precipitation of solid compounds from model electrolytes for liquid dye-sensitized solar cells has a story to tell regarding decomposition processes to be expected in such systems. Of course, the crystal lattice energy for a specific crystalline compounds plays a role in what compound that will eventually precipitate, but the compounds nevertheless serve as indicators for what type of processes that take place in the solar cell electrolytes upon ageing. From the compounds isolated in this study we learn that both ligand exchange processes, double-salt precipitation and oxidation are degradation processes that should not be overlooked when formulating efficient and stable electrolytes for this type of electrochemical system.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2017
Keywords
Crystallography, Dye-sensitized solar cells, Forensics
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-205131 (URN)10.1002/slct.201601756 (DOI)000395533900043 ()
Note

QC 20170517

Available from: 2017-05-17 Created: 2017-05-17 Last updated: 2017-05-17Bibliographically approved
Smith, A. D., Elgammal, K., Fan, X., Lemme, M. C., Delin, A., Råsander, M., . . . Östling, M. (2017). Graphene-based CO2 sensing and its cross-sensitivity with humidity. RSC Advances, 7(36), 22329-22339
Open this publication in new window or tab >>Graphene-based CO2 sensing and its cross-sensitivity with humidity
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2017 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 36, p. 22329-22339Article in journal (Refereed) Published
Abstract [en]

We present graphene-based CO2 sensing and analyze its cross-sensitivity with humidity. In order to assess the selectivity of graphene-based gas sensing to various gases, measurements are performed in argon (Ar), nitrogen (N2), oxygen (O2), carbon dioxide (CO2), and air by selectively venting the desired gas from compressed gas bottles into an evacuated vacuum chamber. The sensors provide a direct electrical readout in response to changes in high concentrations, from these bottles, of CO2, O2, nitrogen and argon, as well as changes in humidity from venting atmospheric air. From the signal response to each gas species, the relative graphene sensitivity to each gas is extracted as a relationship between the percentage-change in graphene's resistance response to changes in vacuum chamber pressure. Although there is virtually no response from O2, N2 and Ar, there is a sizeable cross-sensitivity between CO2 and humidity occurring at high CO2 concentrations. However, under atmospheric concentrations of CO2, this cross-sensitivity effect is negligible – allowing for the use of graphene-based humidity sensing in atmospheric environments. Finally, charge density difference calculations, computed using density functional theory (DFT) are presented in order to illustrate the bonding of CO2 and water molecules on graphene and the alterations of the graphene electronic structure due to the interactions with the substrate and the molecules.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2017
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-206164 (URN)10.1039/C7RA02821K (DOI)000400157700038 ()2-s2.0-85018403239 (Scopus ID)
Note

QC 20170517

Available from: 2017-04-27 Created: 2017-04-27 Last updated: 2019-01-30Bibliographically approved
Asiatici, M., Fischer, A. C., Rodjegard, H., Haasl, S., Stemme, G. & Niklaus, F. (2016). Capacitive inertial sensing at high temperatures of up to 400 degrees C. Sensors and Actuators A-Physical, 238, 361-368
Open this publication in new window or tab >>Capacitive inertial sensing at high temperatures of up to 400 degrees C
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2016 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 238, p. 361-368Article in journal (Refereed) Published
Abstract [en]

High-temperature-resistant inertial sensors are increasingly requested in a variety of fields such as aerospace, automotive and energy. Capacitive detection is especially suitable for sensing at high temperatures due to its low intrinsic temperature dependence. In this paper, we present high-temperature measurements utilizing a capacitive accelerometer, thereby proving the feasibility of capacitive detection at temperatures of up to 400 degrees C. We describe the observed characteristics as the temperature is increased and propose an explanation of the physical mechanisms causing the temperature dependence of the sensor, which mainly involve the temperature dependence of the Young's modulus and of the viscosity and the pressure of the gas inside the sensor cavity. Therefore a static electromechanical model and a dynamic model that takes into account squeeze film damping were developed.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
High temperature, Harsh environment, Inertial sensors, Capacitive detection, Accelerometer
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-183657 (URN)10.1016/j.sna.2015.12.025 (DOI)000370306100040 ()2-s2.0-84954190617 (Scopus ID)
Funder
Knut and Alice Wallenberg FoundationEU, European Research Council, 277879
Note

QC 20160319

Available from: 2016-03-19 Created: 2016-03-18 Last updated: 2018-04-11Bibliographically approved
Schröder, S., Rödjegård, H., Fischer, A. C., Stemme, G. & Niklaus, F. (2016). Fabrication of an Infrared Emitter using a Generic Integration Platform Based on Wire Bonding. Journal of Micromechanics and Microengineering, 26(11), Article ID 115010.
Open this publication in new window or tab >>Fabrication of an Infrared Emitter using a Generic Integration Platform Based on Wire Bonding
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2016 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, no 11, article id 115010Article in journal (Refereed) Published
Abstract [en]

This paper reports a novel approach for the fabrication of infrared (IR)emitters for non-dispersive infrared gas sensing. The proposed concept enables theintegration of superior resistive heater materials with microelectromechanical systems(MEMS) structures. In this study, non-bondable filaments made of nickel chromium areattached to mechanical attachment structures using a fully automated state-of-the-artwire bonder. The formation of the electrical contacts between the integrated filamentsand the electrical contact pattern on the substrate is performed using conventionalgold stud bumping technology. The placement accuracy of the integrated filamentsis evaluated using white-light interferometry, while the contact formation using studbumping to embed the filaments is investigated using focus ion beam milled crosssections.A proof-of-concept IR emitter has been successfully operated and heated upto 960 C in continuous mode for 3 hours.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2016
Keywords
wire bonding, integration platform, stud bumping, non-bondable materials, IR emitter, MEMS-based infrared emitter, NDIR gas sensing
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-194248 (URN)10.1088/0960-1317/26/11/115010 (DOI)000385931300003 ()2-s2.0-84993982778 (Scopus ID)
Funder
EU, European Research Council, 277879Swedish Research Council, 621-2011-4437VINNOVA, 2015-00402
Note

QC 20161121

Available from: 2016-10-21 Created: 2016-10-21 Last updated: 2018-02-07Bibliographically approved
Rajabi, M., Roxhed, N., Shafagh, R. Z., Haraldson, T., Fischer, A. C., van der Wijngaart, W., . . . Niklaus, F. (2016). Flexible and Stretchable Microneedle Patches with Integrated Rigid Stainless Steel Microneedles for Transdermal Biointerfacing. PLoS ONE, 11(12), Article ID e0166330.
Open this publication in new window or tab >>Flexible and Stretchable Microneedle Patches with Integrated Rigid Stainless Steel Microneedles for Transdermal Biointerfacing
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2016 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 12, article id e0166330Article in journal (Refereed) Published
Abstract [en]

This paper demonstrates flexible and stretchable microneedle patches that combine soft and flexible base substrates with hard and sharp stainless steel microneedles. An elastomeric polymer base enables conformal contact between the microneedle patch and the complex topography and texture of the underlying skin, while robust and sharp stainless steel microneedles reliably pierce the outer layers of the skin. The flexible microneedle patches have been realized by magnetically assembling short stainless steel microneedles into a flexible polymer supporting base. In our experimental investigation, the microneedle patches were applied to human skin and an excellent adaptation of the patch to the wrinkles and deformations of the skin was verified, while at the same time the microneedles reliably penetrate the surface of the skin. The unobtrusive flexible and stretchable microneedle patches have great potential for transdermal biointerfacing in a variety of emerging applications such as transdermal drug delivery, bioelectric treatments and wearable bio-electronics for health and fitness monitoring.

Place, publisher, year, edition, pages
Public Library of Science, 2016
National Category
Polymer Technologies Medical Biotechnology
Identifiers
urn:nbn:se:kth:diva-199482 (URN)10.1371/journal.pone.0166330 (DOI)000389587100025 ()2-s2.0-85006051781 (Scopus ID)
Note

QC 20170120

Available from: 2017-01-20 Created: 2017-01-09 Last updated: 2019-03-06Bibliographically approved
Niklaus, F. & Fischer, A. C. (2016). Heterogeneous 3D integration of MOEMS and ICs. In: International Conference on Optical MEMS and Nanophotonics: . Paper presented at 21st International Conference on Optical MEMS and Nanophotonics, OMN 2016, 31 July 2016 through 4 August 2016. IEEE Computer Society
Open this publication in new window or tab >>Heterogeneous 3D integration of MOEMS and ICs
2016 (English)In: International Conference on Optical MEMS and Nanophotonics, IEEE Computer Society, 2016Conference paper, Published paper (Refereed)
Abstract [en]

Heterogeneous integration of micro-opto-electromechanical systems (MOEMS) and integrated circuits (ICs) allows the combination of high-quality optical and photonic MOEMS materials such as monocrystalline silicon (Si) with standard CMOS-based electronic circuits in order to realize complex optical systems. In this paper, we will present examples of such heterogeneous optical systems, including CMOS-integrated SiGe bolometer arrays and CMOS-integrated Si micro-mirror arrays.

Place, publisher, year, edition, pages
IEEE Computer Society, 2016
Keywords
bolometer arrays, CMOS, IC, MEMS, micro-mirror arrays, MOEMS, Wafer-level heterogeneous 3D integration, Bolometers, CMOS integrated circuits, Infrared detectors, Integrated circuits, Integration, Mirrors, Monocrystalline silicon, Nanophotonics, Silicon wafers, Three dimensional integrated circuits, 3-D integration, Bolometer array, Complex optical systems, Heterogeneous integration, Integrated circuits (ICs), Micro opto electro mechanical systems, Micromirror array, Standard CMOS
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-194853 (URN)10.1109/OMN.2016.7565909 (DOI)000389586300098 ()2-s2.0-84990173946 (Scopus ID)9781509010356 (ISBN)
Conference
21st International Conference on Optical MEMS and Nanophotonics, OMN 2016, 31 July 2016 through 4 August 2016
Note

QC 20161208

Available from: 2016-12-08 Created: 2016-11-01 Last updated: 2017-05-17Bibliographically approved
Bleiker, S. J., Fischer, A. C. & Niklaus, F. (2016). High-speed Metal-filling of Through-Silicon Vias (TSVs) by Parallelized Magnetic Assembly of Micro-Wires. In: 2016 IEEE 29th International Conference on Micro Electro Mechanical Systems (MEMS): . Paper presented at 29th IEEE International Conference on Micro Electro Mechanical Systems, MEMS 2016, Shanghai, China, 24 January 2016 through 28 January 2016 (pp. 577-580). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>High-speed Metal-filling of Through-Silicon Vias (TSVs) by Parallelized Magnetic Assembly of Micro-Wires
2016 (English)In: 2016 IEEE 29th International Conference on Micro Electro Mechanical Systems (MEMS), Institute of Electrical and Electronics Engineers (IEEE), 2016, p. 577-580Conference paper, Published paper (Refereed)
Abstract [en]

This work reports a parallelized magnetic assembly method for scalable and cost-effective through-silicon via (TSV) fabrication. Our fabrication approach achieves high throughput by utilizing multiple magnets below the substrate to assemble TSV structures on many dies in parallel. Experimental results show simultaneous filling of four arrays of TSVs on a single substrate, with 100 via-holes each, in less than 20 seconds. We demonstrate that increasing the degree of parallelization by employing more assembly magnets below the substrate has no negative effect on the TSV filling speed or yield, thus enabling scaled-up TSV fabrication on full wafer-level. This method shows potential for industrial application with an estimated throughput of more than 70 wafers per hour in one single fabrication module. Such a TSV fabrication process could offer shorter processing times as well as higher obtainable aspect ratios compared to conventional TSV filling methods.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2016
Series
Proceedings IEEE Micro Electro Mechanical Systems, ISSN 1084-6999
Keywords
TSV, magnetic assembly
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-184232 (URN)10.1109/MEMSYS.2016.7421691 (DOI)000381797300151 ()2-s2.0-84971001486 (Scopus ID)978-1-5090-1973-1 (ISBN)
Conference
29th IEEE International Conference on Micro Electro Mechanical Systems, MEMS 2016, Shanghai, China, 24 January 2016 through 28 January 2016
Funder
EU, European Research Council, 277879VINNOVA, 324189
Note

QC 20161019

Available from: 2016-03-30 Created: 2016-03-30 Last updated: 2017-05-11Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3452-6361

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