Change search
Link to record
Permanent link

Direct link
BETA
Alternative names
Publications (10 of 414) Show all publications
Ribet, F., Wang, X., Laakso, M., Pagliano, S., Niklaus, F., Roxhed, N. & Stemme, G. (2020). Vertical integration of microchips by magnetic assembly and edge wire bonding. MICROSYSTEMS & NANOENGINEERING, 6(1), Article ID 12.
Open this publication in new window or tab >>Vertical integration of microchips by magnetic assembly and edge wire bonding
Show others...
2020 (English)In: MICROSYSTEMS & NANOENGINEERING, ISSN 2055-7434, Vol. 6, no 1, article id 12Article in journal (Refereed) Published
Abstract [en]

The out-of-plane integration of microfabricated planar microchips into functional three-dimensional (3D) devices is a challenge in various emerging MEMS applications such as advanced biosensors and flow sensors. However, no conventional approach currently provides a versatile solution to vertically assemble sensitive or fragile microchips into a separate receiving substrate and to create electrical connections. In this study, we present a method to realize vertical magnetic-field-assisted assembly of discrete silicon microchips into a target receiving substrate and subsequent electrical contacting of the microchips by edge wire bonding, to create interconnections between the receiving substrate and the vertically oriented microchips. Vertical assembly is achieved by combining carefully designed microchip geometries for shape matching and striped patterns of the ferromagnetic material (nickel) on the backside of the microchips, enabling controlled vertical lifting directionality independently of the microchip's aspect ratio. To form electrical connections between the receiving substrate and a vertically assembled microchip, featuring standard metallic contact electrodes only on its frontside, an edge wire bonding process was developed to realize ball bonds on the top sidewall of the vertically placed microchip. The top sidewall features silicon trenches in correspondence to the frontside electrodes, which induce deformation of the free air balls and result in both mechanical ball bond fixation and around-the-edge metallic connections. The edge wire bonds are realized at room temperature and show minimal contact resistance (<0.2 Omega) and excellent mechanical robustness (>168mN in pull tests). In our approach, the microchips and the receiving substrate are independently manufactured using standard silicon micromachining processes and materials, with a subsequent heterogeneous integration of the components. Thus, this integration technology potentially enables emerging MEMS applications that require 3D out-of-plane assembly of microchips.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2020
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-271286 (URN)10.1038/s41378-019-0126-6 (DOI)000517590500001 ()2-s2.0-85079738557 (Scopus ID)
Note

QC 20200331

Available from: 2020-03-31 Created: 2020-03-31 Last updated: 2020-03-31Bibliographically approved
Hauser, J., Stemme, G. & Roxhed, N. (2019). A BLOOD HEMATOCRIT TEST STRIP. In: : . Paper presented at IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS). , 32
Open this publication in new window or tab >>A BLOOD HEMATOCRIT TEST STRIP
2019 (English)Conference paper, Published paper (Other academic)
Abstract [en]

This paper reports a self-propelled microfluidichematocrit (HCT) test that uses the correlation betweenblood hematocrit and wicking distance of blood in a specialpaper matrix. The enabling feature is a novel blood volumemetering method that allows sampling from the fingertipand reliably generates a highly precise blood volume of47.7 ± 1.9 μl (CV 4%) that is transferred into a porouspaper matrix. A dissolvable valve ensures a relaxed timewindow for blood sampling, making it highly user-friendlyand resilient to overfilling. The presented hematocrit teststrip poses a simple, cheap, equipment-free solution forpatient-centric hematocrit measurements.

National Category
Clinical Laboratory Medicine
Identifiers
urn:nbn:se:kth:diva-250573 (URN)
Conference
IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS)
Note

QC 20190625

Available from: 2019-04-30 Created: 2019-04-30 Last updated: 2019-06-25Bibliographically approved
Hauser, J., Lenk, G., Ullah, S., Beck, O., Stemme, G. & Roxhed, N. (2019). An Autonomous Microfluidic Device for Generating Volume-Defined Dried Plasma Spots. Analytical Chemistry, 91(11), 7125-7130
Open this publication in new window or tab >>An Autonomous Microfluidic Device for Generating Volume-Defined Dried Plasma Spots
Show others...
2019 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 91, no 11, p. 7125-7130Article in journal (Refereed) Published
Abstract [en]

Obtaining plasma from a blood sample and preparing it for subsequent analysis is currently a laborious process involving experienced health-care professionals and centrifugation. We circumvent this by utilizing capillary forces and microfluidic engineering to develop an autonomous plasma sampling device that filters and stores an exact amount of plasma as a dried plasma spot (DPS) from a whole blood sample in less than 6 min. We tested 24 prototype devices with whole blood from 10 volunteers, various input volumes (40-80 mu L), and different hematocrit levels (39-45%). The resulting mean plasma volume, assessed gravimetrically, was 11.6 mu L with a relative standard deviation similar to manual pipetting (3.0% vs 1.4%). LC-MS/MS analysis of caffeine concentrations in the generated DPS (12 duplicates) showed a strong correlation (R-2 = 0.99) to, but no equivalence with, concentrations prepared from corresponding plasma obtained by centrifugation. The presented autonomous DPS device may enable patient-centric plasma sampling through minimally invasive finger-pricking and allow generatation of volume-defined DPS for quantitative blood analysis.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Biomedical Laboratory Science/Technology
Identifiers
urn:nbn:se:kth:diva-254080 (URN)10.1021/acs.analchem.9b00204 (DOI)000470793800027 ()31063366 (PubMedID)2-s2.0-85066116426 (Scopus ID)
Note

QC 20190625

Available from: 2019-06-25 Created: 2019-06-25 Last updated: 2019-06-25Bibliographically approved
Last, T. S., Roxhed, N. & Stemme, G. (2019). Demonstration of the first self-sealing aerosol spray nozzle for medical drug delivery. In: Demonstration of first self-sealing aerosol spray nozzle for medical drug delivery: . Paper presented at IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS) (pp. 1-4). , 32
Open this publication in new window or tab >>Demonstration of the first self-sealing aerosol spray nozzle for medical drug delivery
2019 (English)In: Demonstration of first self-sealing aerosol spray nozzle for medical drug delivery, 2019, Vol. 32, p. 1-4Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Portable medical inhaler systems are prone to bacterial contamination and ingrowth. Here we demonstrate thefirst valved aerosol spray chip, a system that sprays a microjet when actuated and seals against bacterial ingrowth into the spray nozzle in the closed state by a sufficiently small gap. The sealing mechanism is realized by placing a valve seat directly underneath the spray orifices. We fabricated and characterized spray chips with and without valve mechanism and show that they haveindistinguishable spray performance. Our system aims to enable the safe reuse of spray chips for multiple spray operations over an extended period, lowering the cost of treatment while increasing patient compliance.

Keywords
BioMEMS, drug delivery, fluidic microjet, inertial microfluidics, respiratory tract disease treatment
National Category
Medical and Health Sciences Medical Engineering
Research subject
Medical Technology
Identifiers
urn:nbn:se:kth:diva-251748 (URN)
Conference
IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS)
Note

QC 20190819

Available from: 2019-05-21 Created: 2019-05-21 Last updated: 2019-08-19Bibliographically approved
Lenk, G., Ullah, S., Stemme, G., Beck, O. & Roxhed, N. (2019). Evaluation of a Volumetric Dried Blood Spot Card Using a Gravimetric Method and a Bioanalytical Method with Capillary Blood from 44 Volunteers. Analytical Chemistry, 91(9), 5558-5565
Open this publication in new window or tab >>Evaluation of a Volumetric Dried Blood Spot Card Using a Gravimetric Method and a Bioanalytical Method with Capillary Blood from 44 Volunteers
Show others...
2019 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 91, no 9, p. 5558-5565Article in journal (Refereed) Published
Abstract [en]

Dried blood spot (DBS) sampling is a promising method for collection of microliter blood samples. However, hematocrit-related bias in combination with subpunch analysis can result in inaccurate quantification of analytes in DBS samples. In this study we use a microfluidic DBS card, designed to automatically collect fixed volume DBS samples irrespective of the blood hematocrit, to measure caffeine concentration in normal finger prick samples obtained from 44 human individuals. Caffeine levels originating from blood drops of unknown volume collected on the volumetric microfluidic DBS card were compared to volume-controlled pipetted DBS samples from the same finger prick. Hematocrit independence and volumetric sampling performances were also verified on caffeine-spiked blood samples in vitro, using both LC-MS/MS and gravimetric methods, on hematocrits from 26 to 62%. The gravimetric measurements show an excellent metering performance of the microfluidic DBS card, with a mean blood sample volume of 14.25 μL ± 3.0% (n = 51). A measured mean bias below 2.9% compared to normal hematocrit (47%) demonstrates that there is no significant hematocrit-induced bias. LC-MS/MS measurements confirm low CV and hematocrit independence of the sampling system and exhibit no substantial mean bias compared to pipetted DBS. Tests with 44 individuals demonstrated applicability of the microfluidic DBS card for direct finger prick blood sampling, and measured caffeine concentrations show a good agreement with measurements of pipetted DBS. The presented concept demonstrates a good volumetric performance which can help to improve the accuracy of DBS analysis by analyzing a whole spot, equivalent to a defined volume of liquid blood.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:kth:diva-251867 (URN)10.1021/acs.analchem.8b02905 (DOI)000467642100017 ()30856315 (PubMedID)2-s2.0-85064830845 (Scopus ID)
Note

QC 20190528

Available from: 2019-05-28 Created: 2019-05-28 Last updated: 2019-06-11Bibliographically approved
Pagliano, S., Gota, F., Raja, S. N., Dubois, V. J., Stemme, G. & Niklaus, F. (2019). Feedback-free electromigrated tunneling junctions from crack-defined gold nanowires. In: Feedback-free electromigrated tunneling junctions from crack-defined gold nanowires: . Paper presented at 32nd IEEE International Conference on Micro Electro Mechanical Systems, Seoul, Korea, from 27-31 January 2019..
Open this publication in new window or tab >>Feedback-free electromigrated tunneling junctions from crack-defined gold nanowires
Show others...
2019 (English)In: Feedback-free electromigrated tunneling junctions from crack-defined gold nanowires, 2019Conference paper, Published paper (Refereed)
Abstract [en]

Tunneling junctions are pairs of electrodes separated by gaps of a few nanometers (< 3 nm) that allow electrons to tunnel across the gap. Tunneling junctions are of great importance for applications such as label-free biomolecule sensing and single molecule electronics, but their fabrication remains difficult and laborious. In this paper, we present a simple 2-stage process for the fabrication of tunneling junctions consisting of electrode pairs made of gold (Au). This is achieved by combining a novel methodology for fabricating crack-defined Au nanowires at wafer-scale with a constant voltage, feedback-free electromigration procedure to form tunneling nanogaps free of debris.

Keywords
tunneling junctions, crack junction, electromigration
National Category
Nano Technology
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-250572 (URN)
Conference
32nd IEEE International Conference on Micro Electro Mechanical Systems, Seoul, Korea, from 27-31 January 2019.
Note

QCR 20190820

Available from: 2019-04-30 Created: 2019-04-30 Last updated: 2019-08-20Bibliographically approved
Pagliano, S., Gota, F., Raja, S. N., Dubois, V. J., Stemme, G. & Niklaus, F. (2019). Feedback-Free Electromigrated Tunneling Junctions from Crack-Defined Gold Nanowires. In: Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS): . Paper presented at 2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS), 27-31 Jan. 2019 (pp. 365-367). IEEE conference proceedings
Open this publication in new window or tab >>Feedback-Free Electromigrated Tunneling Junctions from Crack-Defined Gold Nanowires
Show others...
2019 (English)In: Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), IEEE conference proceedings, 2019, p. 365-367Conference paper, Published paper (Refereed)
Abstract [en]

Tunneling junctions are pairs of electrodes separated by gaps of a few nanometers that allow electrons to tunnel across the gap. Tunneling junctions are of great importance for applications such as label-free biomolecule sensing and single molecule electronics, but their fabrication remains difficult and laborious. In this paper, we present a simple 2-stage process for the fabrication of tunneling junctions consisting of electrode pairs made of gold (Au). This is achieved by combining a novel methodology for fabricating crack-defined Au nanowires at wafer-scale with a constant voltage, feedback-free electromigration procedure to form tunneling nanogaps free of debris.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2019
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-268311 (URN)10.1109/MEMSYS.2019.8870698 (DOI)2-s2.0-85074354086 (Scopus ID)
Conference
2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS), 27-31 Jan. 2019
Note

QC 20200310

Available from: 2020-03-10 Created: 2020-03-10 Last updated: 2020-03-10Bibliographically approved
Enrico, A., Dubois, V. J., Niklaus, F. & Stemme, G. (2019). Manufacturing of Sub-20 NM Wide Single Nanowire Devices using Conventional Stepper Lithography. In: Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS): . Paper presented at 2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS), 27-31 Jan. 2019 (pp. 244-247). IEEE conference proceedings
Open this publication in new window or tab >>Manufacturing of Sub-20 NM Wide Single Nanowire Devices using Conventional Stepper Lithography
2019 (English)In: Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), IEEE conference proceedings, 2019, p. 244-247Conference paper, Published paper (Refereed)
Abstract [en]

Single nanowires have a broad range of applications in chemical and bio-sensing, photonics, and material science, but realizing individual nanowire devices in a scalable manner remains extremely challenging. This work presents a scalable and flexible method to realize single gold nanowire devices. We use conventional optical stepper lithography to generate notched beam structures, and crack lithography to obtain sub-20-nm-wide nanogaps at the notches, thereby obtaining a suitable shadow mask to define a single nanowire device. Then a gold evaporation step through the shadow mask forms the individual gold nanowires with positional and dimensional accuracy and with electrical contacts to probing pads.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2019
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-268309 (URN)10.1109/MEMSYS.2019.8870647 (DOI)2-s2.0-85074363946 (Scopus ID)
Conference
2019 IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS), 27-31 Jan. 2019
Note

QC 20200310

Available from: 2020-03-10 Created: 2020-03-10 Last updated: 2020-03-10Bibliographically approved
Enrico, A., Dubois, V. J., Niklaus, F. & Stemme, G. (2019). Scalable Manufacturing of Single Nanowire Devices Using Crack-Defined Shadow Mask Lithography. ACS Applied Materials and Interfaces, 11(8), 8217-8226
Open this publication in new window or tab >>Scalable Manufacturing of Single Nanowire Devices Using Crack-Defined Shadow Mask Lithography
2019 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 8, p. 8217-8226Article in journal (Refereed) Published
Abstract [en]

Single nanowires (NWs) have a broad range of applications in nanoelectronics, nanomechanics, and nano photonics, but, to date, no technique can produce single sub 20 nm wide NWs with electrical connections in a scalable fashion. In this work, we combine conventional optical and crack lithographies to generate single NW devices with controllable and predictable dimensions and placement and with individual electrical contacts to the NWs. We demonstrate NWs made of gold, platinum, palladium, tungsten, tin, and metal oxides. We have used conventional i-line stepper lithography with a nominal resolution of 365 nm to define crack lithography structures in a shadow mask for large-scale manufacturing of sub-20 nm wide NWs, which is a 20-fold improvement over the resolution that is possible with the utilized stepper lithography. Overall, the proposed method represents an effective approach to generate single NW devices with useful applications in electrochemistry, photonics, and gas- and biosensing.

National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-250298 (URN)10.1021/acsami.8b19410 (DOI)000460365300061 ()30698940 (PubMedID)2-s2.0-85061896644 (Scopus ID)
Note

QC 20190430

Available from: 2019-04-29 Created: 2019-04-29 Last updated: 2020-03-09Bibliographically approved
Wang, X., Schroder, S., Enrico, A., Kataria, S., Lemme, M. C., Niklaus, F., . . . Roxhed, N. (2019). Transfer printing of nanomaterials and microstructures using a wire bonder. Journal of Micromechanics and Microengineering, 29(12), Article ID 125014.
Open this publication in new window or tab >>Transfer printing of nanomaterials and microstructures using a wire bonder
Show others...
2019 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 29, no 12, article id 125014Article in journal (Refereed) Published
Abstract [en]

Scalable and cost-efficient transfer of nanomaterials and microstructures from their original fabrication substrate to a new host substrate is a key challenge for realizing heterogeneously integrated functional systems, such as sensors, photonics, and electronics. Here we demonstrate a high-throughput and versatile integration method utilizing conventional wire bonding tools to transfer-print carbon nanotubes (CNTs) and silicon microstructures. Standard ball stitch wire bonding cycles were used as scalable and high-speed pick-and-place operations to realize the material transfer. Our experimental results demonstrated successful transfer printing of single-walled CNTs (100 m-diameter patches) from their growth substrate to polydimethylsiloxane, parylene, or Au/parylene electrode substrates, and realization of field emission cathodes made of CNTs on a silicon substrate. Field emission measurements manifested excellent emission performance of the CNT electrodes. Further, we demonstrated the utility of a high-speed wire bonder for transfer printing of silicon microstructures (60 m 60 m 20 m) from the original silicon on insulator substrate to a new host substrate. The achieved placement accuracy of the CNT patches and silicon microstructures on the target substrates were within 4 m. These results show the potential of using established and extremely cost-efficient semiconductor wire bonding infrastructure for transfer printing of nanomaterials and microstructures to realize integrated microsystems and flexible electronics.

Place, publisher, year, edition, pages
IOP PUBLISHING LTD, 2019
Keywords
transfer printing, wire bonding, heterogeneous integration, carbon nanotubes, field emission, flexible electronics, assembly
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-264155 (URN)10.1088/1361-6439/ab4d1f (DOI)000493114400001 ()2-s2.0-85076055727 (Scopus ID)
Note

QC 20191209

Available from: 2019-12-09 Created: 2019-12-09 Last updated: 2020-01-07Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9552-4234

Search in DiVA

Show all publications