| 1. |
- Ericsson, Per, et al.
(författare)
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Toward 17µm pitch heterogeneously integrated Si/SiGe quantum well bolometer focal plane arrays
- 2011
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Ingår i: Infrared Technology and Applications XXXVII. - : SPIE - International Society for Optical Engineering. ; , s. 801216-1-801216-9
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Konferensbidrag (refereegranskat)abstract
- Most of today's commercial solutions for un-cooled IR imaging sensors are based on resistive bolometers using either Vanadium oxide (VOx) or amorphous Silicon (a-Si) as the thermistor material. Despite the long history for both concepts, market penetration outside high-end applications is still limited. By allowing actors in adjacent fields, such as those from the MEMS industry, to enter the market, this situation could change. This requires, however, that technologies fitting their tools and processes are developed. Heterogeneous integration of Si/SiGe quantum well bolometers on standard CMOS read out circuits is one approach that could easily be adopted by the MEMS industry. Due to its mono crystalline nature, the Si/SiGe thermistor material has excellent noise properties that result in a state-ofthe- art signal-to-noise ratio. The material is also stable at temperatures well above 450°C which offers great flexibility for both sensor integration and novel vacuum packaging concepts. We have previously reported on heterogeneous integration of Si/SiGe quantum well bolometers with pitches of 40μm x 40μm and 25μm x 25μm. The technology scales well to smaller pixel pitches and in this paper, we will report on our work on developing heterogeneous integration for Si/SiGe QW bolometers with a pixel pitch of 17μm x 17μm.
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| 2. |
- Forsberg, Fredrik, et al.
(författare)
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CMOS-integrated Si/SiGe quantum-well infrared microbolometer focal plane arrays manufactured with very large-scale heterogeneous 3-d integration
- 2015
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers Inc.. - 0792-1233 .- 1077-260X .- 1558-4542. ; 21:4
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate infrared focal plane arrays utilizing monocrystalline silicon/silicon-germanium (Si/SiGe) quantum-well microbolometers that are heterogeneously integrated on top of CMOS-based electronic read-out integrated circuit substrates. The microbolometers are designed to detect light in the long wavelength infrared (LWIR) range from 8 to 14 μm and are arranged in focal plane arrays consisting of 384 × 288 microbolometer pixels with a pixel pitch of 25 μm × 25 μm. Focal plane arrays with two different microbolometer designs have been implemented. The first is a conventional single-layer microbolometer design and the second is an umbrella design in which the microbolometer legs are placed underneath the microbolometer membrane to achieve an improved pixel fill-factor. The infrared focal plane arrays are vacuum packaged using a CMOS compatible wafer bonding and sealing process. The demonstrated heterogeneous 3-D integration and packaging processes are implemented at wafer-level and enable independent optimization of the CMOS-based integrated circuits and the microbolometer materials. All manufacturing is done using standard semiconductor and MEMS processes, thus offering a generic approach for integrating CMOS-electronics with complex miniaturized transducer elements
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| 3. |
- Forsberg, Fredrik, et al.
(författare)
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Heterogeneous 3D integration of 17 μm pitch Si/SiGe quantum well bolometer arrays for infrared imaging systems
- 2013
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Ingår i: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 0960-1317 .- 1361-6439. ; 23:4
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on the realization of 17 μm × 17 μm pitch bolometer arrays for uncooled infrared imagers. Microbolometer arrays have been available in primarily defense applications since the mid-1980s and are typically based on deposited thin films on top of CMOS wafers that are surface-machined into sensor pixels. This paper instead focuses on the heterogeneous integration of monocrystalline Si/SiGe quantum-well-based thermistor material in a CMOS-compliant process using adhesive wafer bonding. The high-quality monocrystalline thermistor material opens up for potentially lower noise compared to commercially available uncooled microbolometer arrays together with a competitive temperature coefficient of resistance (TCR). Characterized bolometers had a TCR of -2.9% K-1 in vacuum, measured thermal conductances around 5 × 10-8 W K-1 and thermal time constants between 4.9 and 8.5 ms, depending on the design. Complications in the fabrication of stress-free bolometer legs and low-noise contacts are discussed and analyzed.
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| 4. |
- Forsberg, Fredrik, et al.
(författare)
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High-Performance Infrared Micro-Bolometer Arrays Manufactured Using Very Large Scale Heterogeneous Integration
- 2011
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Ingår i: OMN2011. ; , s. 9-10
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Konferensbidrag (refereegranskat)abstract
- This paper reports on the implementation and characterization of arrays of uncooled infrared bolometers containing mono-crystalline Si/SiGe quantum well (QW) thermistors. The bolometer arrays are integrated on silicon fan-out wafers using very-large scale heterogeneous integration that is compatible with standard CMOS wafers. Infrared bolometer arrays with 320x240 pixels and pixel pitches of 25 mu m x 25 mu m and 17 mu m x 17 mu m have been implemented, respectively.
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| 5. |
- Forsberg, Fredrik, et al.
(författare)
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Very large scale heterogeneous integration (VLSHI) and wafer-level vacuum packaging for infrared bolometer focal plane arrays
- 2013
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Ingår i: Infrared physics & technology. - : Elsevier BV. - 1350-4495 .- 1879-0275. ; 60, s. 251-259
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Tidskriftsartikel (refereegranskat)abstract
- Imaging in the long wavelength infrared (LWIR) range from 8 to 14 μm is an extremely useful tool for non-contact measurement and imaging of temperature in many industrial, automotive and security applications. However, the cost of the infrared (IR) imaging components has to be significantly reduced to make IR imaging a viable technology for many cost-sensitive applications. This paper demonstrates new and improved fabrication and packaging technologies for next-generation IR imaging detectors based on uncooled IR bolometer focal plane arrays. The proposed technologies include very large scale heterogeneous integration for combining high-performance, SiGe quantum-well bolometers with electronic integrated read-out circuits and CMOS compatible wafer-level vacuum packing. The fabrication and characterization of bolometers with a pitch of 25 μm × 25 μm that are arranged on read-out-wafers in arrays with 320 × 240 pixels are presented. The bolometers contain a multi-layer quantum well SiGe thermistor with a temperature coefficient of resistance of -3.0%/K. The proposed CMOS compatible wafer-level vacuum packaging technology uses Cu-Sn solid-liquid interdiffusion (SLID) bonding. The presented technologies are suitable for implementation in cost-efficient fabless business models with the potential to bring about the cost reduction needed to enable low-cost IR imaging products for industrial, security and automotive applications.
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| 6. |
- Roxhed, Niclas, et al.
(författare)
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A Compact, Low-cost Microliter-range Liquid Dispenser based on Expandable Microspheres
- 2006
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Ingår i: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 0960-1317 .- 1361-6439. ; 16:12, s. 2740-2746
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a new low-cost liquid dispenser for the dispensing of microliters to milliliter volumes. The dispensing mechanism is based on a thermal actuator where highly expandable microspheres expand into a liquid reservoir consequently displacing any stored liquid. All device components are made out of low-cost materials and the fabrication process has the potential for high volume batch manufacturing. The device utilizes the property of the expandable microspheres to form a heat insulating layer between the heat source and the delivered liquid. Moreover, it does not require any feed back or complicated flow metering. The device was successfully tested showing a mean dispensed volume of 101 mu 1 with a standard deviation of 3.2% and with a maximum temperature of 59 degrees C in the liquid during actuation. It was shown that the dispenser is strong enough to deliver against counter pressures as high as 75 kPa. The device can also function as a low flow rate dispenser as demonstrated in a microfluidic dye laser application. The flow rate can be controlled between 1 mu 1 h(-1) and 2400 mu 1 h(-1) by adjusting the actuation power.
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| 7. |
- Roxhed, Niclas, et al.
(författare)
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Compact seamless integration of active dosing and actuation with microneedles for transdermal drug delivery
- 2006
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Ingår i: MEMS 2006. - New York : IEEE. - 0780394755 ; , s. 414-417
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Konferensbidrag (refereegranskat)abstract
- This paper presents the seamless integration of a dosing and actuation unit capable of controlled release of liquid in the microliter range at very low flow-rates (mu l/h) with painless, hollow microneedles for transdermal liquid delivery. This novel system was tested in-vivo on human and rat skin and allows the detailed study of liquid uptake in biological tissue. Experiments with infusion of radioactive marker into rat shows that the actively infused liquid was successfully delivered trough the skin layer and absorbed by the circulatory system. It was also noted that, for the given way of device attachment, the amount of liquid that can be absorbed by the skin tissue is limited to a few mu l/h. The presented device represents the first step towards a transdermal patch allowing for applications where very precise amounts of liquid need to be delivered into the skin (e.g. insulin). The novelty of this work is the significant step from non-integrated modules earlier presented by our and other groups into a complete microsystem.
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| 8. |
- Roxhed, Niclas, et al.
(författare)
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LOW COST DEVICE FOR PRECISE MICROLITER RANGE LIQUID DISPENSIN
- 2004
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Ingår i: 17th IEEE International Conference on Micro Electro Mechanical Systems (IEEE MEMS 2004). - New York : IEEE conference proceedings. - 078038265X ; , s. 326-329
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Konferensbidrag (refereegranskat)abstract
- In this work we present the fabrication and testing of a thermally actuated one-shot liquid dispenser, which actuation is based on highly expandable microspheres. We show an uncomplicated, fully functional, low cost device for use in medical disposables, e.g. transdermal systems based on microneedles. All device components are made out of low cost materials and fabrication processes have the potential for high volume batch manufacturing. The device utilizes the properties of the expandable microspheres to form a heat insulating layer to the delivered liquid. Moreover, it does not require any feed-back or complicated flow metering. The device was successfully tested showing a mean dispensed liquid of 101 mul with a relative standard deviation of 3.2% and with a maximum temperature of 59 degreesC in the liquid during actuation. No back-flow was observed for the device.
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| 9. |
- Roxhed, Niclas, et al.
(författare)
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Low-cost uncooled microbolometers for thermal imaging
- 2010
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Ingår i: OPTICAL SENSING AND DETECTION. - : SPIE. - 9780819481993 ; , s. 772611-
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Konferensbidrag (refereegranskat)abstract
- Cost efficient integration technologies and materials for manufacturing of uncooled infrared bolometer focal plane arrays (FPA) are presented. The technology platform enables 320x240 pixel resolution with a pitch down to 20 mu m and very low NETD. A heterogeneous 3D MEMS integration technology called SOIC (Silicon-On-Integrated-Circuit) is used to combine high performance Si/SiGe bolometers with state-of-the-art electronic read-out-integrated-circuits. The SOIC integration process consists of: (a) Separate fabrication of the CMOS wafer and the MEMS wafer. (b) Adhesive wafer bonding. (c) Sacrificial removal of the MEMS handle wafer. (d) Via-hole etching. (e) Via formation and MEMS device definition. (f) Sacrificial etching of the polymer adhesive. We will present an optimized process flow that only contains dry etch processes for the critical process steps. Thus, extremely small, sub-micrometer feature sizes and vias can be implemented for the infrared bolometer arrays. The Si/SiGe thermistor is grown epitaxially, forming a mono-crystalline multi layer structure. The temperature coefficient of resistance (TCR) is primarily controlled by the concentration of Ge present in the strained SiGe layers. TCR values of more than 3%/K can be achieved with a low signal-to-noise ratio due to the mono-crystalline nature of the material. In addition to its excellent electrical properties, the thermistor material is thermally stable up to temperatures above 600 degrees C, thus enabling the novel integration and packaging techniques described in this paper. Vacuum sealing at the wafer level reduces the overall costs compared to encapsulation after die singulation. Wafer bonding is performed using a Cu-Sn based metallic bonding process followed by getter activation at >= 350 degrees C achieving a pressure in the 0.001 mbar range. After assembling, the final metal phases are stable and fully compatible with high-temperature processes. Hermeticity over the product lifetime is accomplished by well-controlled electro-deposition of metal layers, optimized bonding parameters and a suitable bond frame design.
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| 10. |
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| 11. |
- Roxhed, Niclas, et al.
(författare)
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Painless drug delivery through microneedle-based transdermal patches featuring active infusion
- 2008
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Ingår i: IEEE Transactions on Biomedical Engineering. - 0018-9294 .- 1558-2531. ; 55:3, s. 1063-1071
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the first microneedle-based transdermal patch with integrated active dispensing functionality. The electrically controlled system consists of a low-cost dosing and actuation unit capable of controlled release of liquid in the microliter range at low flow-rates and minimally invasive, side-opened, microneedles. The system was successfully tested in vivo by insulin administration to diabetic rats. Active infusion of insulin at 2 mul/h was compared to passive, diffusion-driven, delivery. Continuous active infusion caused significantly higher insulin concentrations in blood plasma. After a 3-h delivery period, the insulin concentration was five times larger compared to passive delivery. Consistent with insulin concentrations, actively administered insulin resulted in a significant decrease of blood glucose levels. Additionally, insertion and liquid injection was verified on human skin. This study shows the feasibility of a patch-like system with on-board liquid storage and dispensing capability. The proposed device represents a first step towards painless and convenient administration of macromolecular drugs such as insulin or vaccines.
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| 12. |
- Samel, Björn, et al.
(författare)
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A Disposable Lab-on-a-chip Platform with Embedded Fluid Actuators for Active Nanoliter Liquid Handling
- 2007
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Ingår i: Biomedical microdevices (Print). - : Springer Science and Business Media LLC. - 1387-2176 .- 1572-8781. ; 9:1, s. 61-67
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Tidskriftsartikel (refereegranskat)abstract
- In this work we present the development of a disposable liquid handling lab-on-a-chip (LOC) platform with embedded actuators for applications in analytical chemistry. The proposed platform for nanoliter liquid handling is based on a thermally responsive silicone elastomer composite, consisting of PDMS and expandable microspheres. In our LOC platform, we integrate active dosing, transportation and merging of nanoliter liquid volumes. The disposable platform successfully demonstrates precise sample volume control with smart microfluidic manipulation and on-chip active microfluidic components. It is entirely fabricated from low-cost materials using wafer-level processing. Moreover, an enzymatic reaction and real-time detection was successfully conducted to exemplify its applicability as an LOC.
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| 13. |
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| 14. |
- Samel, Björn, et al.
(författare)
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A Thermally Responsive PDMS Composite and its Microfluidic Applications
- 2007
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Ingår i: Journal of microelectromechanical systems. - 1057-7157 .- 1941-0158. ; 16:1, s. 50-57
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes a novel composite actuator for controlled liquid actuation in microsystems which is based on a thermally responsive elastomer. The composite actuator consists of expandable microspheres incorporated in a polydimethylsiloxane (PDMS) matrix and entails the merits of both PDMS and expandable microspheres. The main characteristic of the composite actuator is to expand upon heat. The expansion is irreversible and the relative volume increase is measured up to 270% of its original volume after heating to 80 degrees C. The composite was used to fabricate single-use microfluidic pumps and valves. We show the displacement of liquids in the range of nanoliters even against counter pressures up to 100 kPa. Moreover, liquid flow in microchannels was entirely blocked by means of the integrated valves. The valves can withstand pressures up to 140 kPa. The devices are fabricated using low-cost materials only, and the composite actuator allows using wafer-level processing. The fluidic components based on the novel composite are highly integrable and do not require external actuators.
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| 15. |
- Samel, Björn, et al.
(författare)
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Active liquid aspiration and dispensing based on an expanding PDMS composite
- 2007
-
Ingår i: PROCEEDINGS OF THE IEEE TWENTIETH ANNUAL INTERNATIONAL CONFERENCE ON MICRO ELECTRO MECHANICAL SYSTEMS. - 9781424409501 ; , s. 802-805
-
Konferensbidrag (refereegranskat)abstract
- In this work we present the development of a liquid aspiration and dispensing unit which is based on a single-use thermally expanding PDMS composite. The composite actuator consists of expandable microspheres incorporated into a PDMS matrix and allows for locally altering its topography by means of individually addressable integrated heaters. Devices were designed in order to enable the generation of a cavity by the expansion of the composite actuator and are entirely fabricated from low-cost materials using wafer-level processes only. The fabricated devices successfully demonstrated controlled liquid aspiration and release thereafter of liquid volumes ranging from 180nl to 815nl.
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| 16. |
- Samel, Björn, et al.
(författare)
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Expandable microspheres incorporated in a PDMS matrix : A novel thermal composite actuator for liquid handling in microfluidic applications
- 2003
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Ingår i: BOSTON TRANSDUCERS'03. - NEW YORK : IEEE. - 0780377311 ; , s. 1558-1561
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Konferensbidrag (refereegranskat)abstract
- In this study a novel actuator concept based on expandable microspheres incorporated in a PDMS matrix is presented. Merging the merits of the two substances gives the resulting composite material novel application possibilities as well as novel performance and processing properties. The expansion behavior of the composite was investigated and a maximum volume change of 270% of its original volume was measured after heating to 80degreesC. Applying a heat treatment to the composite shows its capability of filling out deep voids. The composite shows very good applicability as embedded actuator and may be appropriate for various applications. Furthermore, the applicability of the composite for replica molding has been demonstrated by creating inverse replicated features in the cured composite. We show the investigation of fabrication, expansion and application techniques by means of a novel actuator concept for liquid handling.
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| 17. |
- Samel, Björn, et al.
(författare)
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Liquid Aspiration and Dispensing Based on an Expanding PDMS Composite
- 2008
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Ingår i: Journal of microelectromechanical systems. - : IEEE Press. - 1057-7157 .- 1941-0158. ; 17:5, s. 1254-1262
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present the development of active liquid aspiration and dispensing units designed for vertical, as well as lateral, liquid aspiration. The devices are based on a single-use thermally expanding polydimethylsiloxane (PDMS) composite, which allows altering its surface topography by means of individually addressable integrated heaters. Devices are designed in order to create an enclosed cavity in the system, due to locally expanding the initially unstructured composite. This enables negative volume displacement and leads to the event of liquid aspiration. To enable this device functionality, two different techniques of selectively creating permanent PDMS bonds have been developed. One approach utilizes the plasma-assisted PDMS bonding technique, together with a patterned antistiction layer to form reversibly, as well as irreversibly, bonded regions. Another approach utilizes microcontact printing of PDMS curing agent, which serves as a patterned intermediate layer for adhesive bonding. Fabricated prototype devices successfully demonstrated the aspiration and release of liquid volumes ranging from 28 to 815 nL. The devices are entirely fabricated from low-cost materials, using wafer-level processes only and do not require external means for liquid actuation.
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| 18. |
- Samel, Björn, et al.
(författare)
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Nanoliter liquid handling on a low cost disposable with embedded fluid actuators
- 2005
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Ingår i: Transducers '05, Digest of Technical Papers, Vols 1 and 2. - NEW YORK : IEEE. ; , s. 356-359
-
Konferensbidrag (refereegranskat)abstract
- In this work we present the development of a disposable liquid handling lab-on-a-chip (LOC) system with embedded actuators for applications in analytical chemistry. The proposed nanoliter liquid handling is based on a temperature sensitive silicone elastomer composite, consisting of PDMS and expandable microspheres. In our LOC system, we integrate active dosing, transportation and merging of nanoliter liquid volumes. The disposable successfully demonstrates precise sample volume control with smart microfluidic manipulation and on-chip active microfluidic components. It is entirely fabricated from low-cost materials using wafer-level processing. Moreover, a biochemical luminescent reaction was successfully conducted to exemplify its applicability as an LOC.
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| 19. |
- Samel, Björn, 1977-
(författare)
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Novel Microfluidic Devices Based on a Thermally Responsive PDMS Composite
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The field of micro total analysis systems (μTAS) aims at developments toward miniaturized and fully integrated lab-on-a-chip systems for applications, such as drug screening, drug delivery, cellular assays, protein analysis, genomic analysis and handheld point-of-care diagnostics. Such systems offer to dramatically reduce liquid sample and reagent quantities, increase sensitivity as well as speed of analysis and facilitate portable systems via the integration of components such as pumps, valves, mixers, separation units, reactors and detectors. Precise microfluidic control for such systems has long been considered one of the most difficult technical barriers due to integration of on-chip fluidic handling components and complicated off-chip liquid control as well as fluidic interconnections. Actuation principles and materials with the advantages of low cost, easy fabrication, easy integration, high reliability, and compact size are required to promote the development of such systems. Within this thesis, liquid displacement in microfluidic applications, by means of expandable microspheres, is presented as an innovative approach addressing some of the previously mentioned issues. Furthermore, these expandable microspheres are embedded into a PDMS matrix, which composes a novel thermally responsive silicone elastomer composite actuator for liquid handling. Due to the merits of PDMS and expandable microspheres, the composite actuator's main characteristic to expand irreversibly upon generated heat makes it possible to locally alter its surface topography. The composite actuator concept, along with a novel adhesive PDMS bonding technique, is used to design and fabricate liquid handling components such as pumps and valves, which operate at work-ranges from nanoliters to microliters. The integration of several such microfluidic components promotes the development of disposable lab-on-a-chip platforms for precise sample volume control addressing, e.g. active dosing, transportation, merging and mixing of nanoliter liquid volumes. Moreover, microfluidic pumps based on the composite actuator have been incorporated with sharp and hollow microneedles to realize a microneedle-based transdermal patch which exhibits on-board liquid storage and active dispensing functionality. Such a system represents a first step toward painless, minimally invasive and transdermal administration of macromolecular drugs such as insulin or vaccines. The presented on-chip liquid handling concept does not require external actuators for pumping and valving, uses low-cost materials and wafer-level processes only, is highly integrable and potentially enables controlled and cost-effective transdermal microfluidic applications, as well as large-scale integrated fluidic networks for point-of care diagnostics, disposable biochips or lab-on-a-chip applications. This thesis discusses several design concepts for a large variety of microfluidic components, which are promoted by the use of the novel composite actuator. Results on the successful fabrication and evaluation of prototype devices are reported herein along with comprehensive process parameters on a novel full-wafer adhesive bonding technique for the fabrication of PDMS based microfluidic devices.
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| 20. |
- Samel, Björn, et al.
(författare)
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Single-use microfluidic pumps and valves based on a thermally responsive PDMS composite : Technical Digest
- 2005
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Ingår i: MEMS 2005 Miami. - : IEEE. - 0780387325 ; , s. 690-693
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Konferensbidrag (refereegranskat)abstract
- In this work we present active microfluidic liquid handling integrated on-chip with no need for external actuators. The concept is based on a temperature sensitive silicone elastomer composite, consisting of PDMS and expandable microspheres. We successfully fabricated single-use microfluidic pumps and displaced liquids in the range of nanoliters even against counter pressures up to 100kPa. Moreover, liquid flow in a microchannel was entirely blocked by means of integrated valves. The valves could withstand pressures up to 140kPa. The devices were fabricated entirely from low cost materials and allow wafer-level processing to be used.
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| 21. |
- Samel, Björn, et al.
(författare)
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The fabrication of microfluidic structures by means of full-wafer adhesive bonding using a poly(dimethylsiloxane) catalyst
- 2007
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Ingår i: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 0960-1317 .- 1361-6439. ; 17:8, s. 1710-1714
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we present the use of a PDMS ( poly( dimethylsiloxane)) curing-agent as the intermediate layer for adhesive full-wafer bonding suitable for fabrication of microfluidic structures. The curing-agent of the two-component silicone rubber (Sylgard 184) is spin coated on a substrate, brought into contact with another PDMS layer and heat cured to create an irreversible seal which is as strong as or even stronger than plasma-assisted PDMS bonding. The maximum bond strength is measured to 800 kPa when bonding together PDMS and silicon. The applicability of the new PDMS adhesive bonding method is verified by means of fabricating microfluidic structures. Using this method allows for wafer-level bonding of PDMS to various materials such as PDMS, glass or silicon and more importantly to selectively bond different layers by using a patterned adhesive bonding technique. Moreover, precise alignment of the structural layers is facilitated since curing is initiated upon heat which is an advantage when fabricating multilayer microfluidic devices.
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| 22. |
- Samel, Björn, et al.
(författare)
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Wafer-Level Process for Single-Use Buckling Film Microliter-Range Pumps
- 2007
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Ingår i: Journal of microelectromechanical systems. - 1057-7157 .- 1941-0158. ; 16:4, s. 795-801
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present the development of disposable single-use microfluidic pumps entirely based on a straightforward wafer-level fabrication scheme, which allows for precise integrated active dosing in the microliter range. To accomplish stroke-lengths needed for microliter-range applications, we utilize a new method of bending of a unimorph-composite-actuator film. The unimorph composite actuator consists of a temperature-sensitive silicone elastomer composite, i.e., polydimethylsiloxane, with incorporated expandable microspheres. The fabricated micropumps successfully demonstrated precise liquid-volume control, both at low and high flow rates, and show a standard deviation of 6.7% for consecutive pump experiments. Moreover, the method of fluorescent thermometry was used to measure the thermal load on liquid volumes dispensed with the micropumps. The liquid temperature reaches a maximum of 50 degrees C during the operation. The presented fully integrated single-use micropumps are electrically controllable, do not require external means for liquid actuation, are made of low-cost materials only, and might potentially be used in drug-delivery applications.
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| 23. |
- Sjöberg, Per-Olof, et al.
(författare)
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Sverige i halvledarvärlden – analys och förslag till strategi
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Den brist på halvledare som industrin upplevt under 2021 har satt den annars tämligen anonyma halvledarindustrin i rampljuset såväl i Sverige som i Europa, USA och globalt. Hur länge denna brist kommer att bestå är en viktig fråga för industrin, som dock är svår att svara på. Enligt internationella analytiker kommer industrin att uppleva halvledarbrist fram till sommaren 2022 och eventuellt in på nästa höst eller eventuellt längre, varefter det föreligger en risk för överproduktion då lager förmodligen byggts upp bland avnämare. Erfarenheterna från tidigare halvledarbrister är att de så småningom övergår i överskott. Men den nuvarande bristen kan sannolikt kräva längre tid för detta än tidigare brister. Främsta skälet är att de halvledarfabriker som för närvarande är under uppbyggnad för att råda bot på bristen lider av samma överhettade försörjningskedjor som övrig industri, med förseningar av allt från vitala utrustningar till förbrukningsmateriel, och att det därför troligen kommer att ta längre tid än planerat att få dem i drift. Detta kan i värsta fall innebära att det rentav kan ta ett eller flera år längre tid än analytikerna förutspått innan försörjningsläget är normalt. Sverige är en del av det globala halvledarekosystemet – ett komplext ekosystem som kännetecknas av hög grad av arbetsfördelning, hög kapitalintensitet, hög kunskapsintensitet, långa produktionstider, stark internationalisering och starka inlåsningseffekter. Sverige interagerar med detta globala ekosystem på två sätt - som leverantör av produkter och tjänster i ett antal nischer där vi uppvisar global spetskompetens samt som avnämare av halvledarprodukter för industriella behov. Båda dessa sidor behöver stärkas för att a) våra SMF och stora företag ska kunna få tillgång till de halvledare och system byggda på halvledare som krävs för den produktion av produkter och tjänster som bidrar till Sveriges välstånd, b) svenska industriföretag ska kunna säkra tillgång till den kompetens och de tjänster som krävs då industrins produkter innehåller allt större mängd halvledare, och c) för att maximera möjligheterna för svenska halvledar- och elektronikinnovationer att hävda sig på världsmarknaden, och på så sätt bidra till landets välstånd. Det övergripande målet för Sverige bör vara att använda vår nationella styrka inom innovation som hävstång, och fokusera de starka specialiserade kompetenserna som finns här i landet, jämte långsiktiga investeringar i forskning inom halvledarteknik, systemdesign och halvledarmaterial, i syfte att med samlad kraft nå följande strategiska mål: 1) Etablera Sverige som ett halvledarinnovationsland genom att stärka vårt innovationssystem för halvledare och halvledarmaterial. 2) Få utväxling på de svenska investeringarna i forsknings- och innovationsinfrastruktur för design och produktion av halvledare. 3) Säkra och vidmakthåll en roll för Sverige i halvledarindustrin, inte minst genom svensk representation i de organ och församlingar som beslutar om framtida europeiska investeringar. För att nå dessa mål krävs stark samverkan mellan industri, akademi, institut och offentlig sektor, och långsiktiga såväl publika som privata investeringar i utbildning, forskningsinfrastruktur, test- och demonstrationsanläggningar och i startup- och scaleup-bolag. RISE åsikt är att Sverige därtill bör ta aktiv del i EU-initiativ som den europeiska halvledaralliansen (Alliance on Processor and Semiconductor Technologies) och European Chips Act. Påpekas bör att dessa mål är långsiktiga och kräver kontinuerligt arbete och finansiering under många år framöver. De löser inte industrins kortsiktiga behov av halvledare, och det kommer att ta tid att säkra industrins behov av halvledarkompetens. Med en väl genomförd strategi skulle dock dessa behov i högre grad kunna tillgodoses samtidigt som vårt lands bidrag till det globala halvledarekosystemet skulle växa kraftigt, till fromma för vårt gemensamma välstånd.
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Ingår i: Materials science & engineering. R, Reports. - : Elsevier BV. - 0927-796X .- 1879-212X. ; 56:06-jan, s. 1-129
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Forskningsöversikt (refereegranskat)abstract
- This paper provides a detailed overview of developments in transducer materials technology relating to their current and future applications in micro-scale devices. Recent advances in piezoelectric, magnetostrictive and shape-memory alloy systems are discussed and emerging transducer materials such as magnetic nanoparticles, expandable micro-spheres and conductive polymers are introduced. Materials properties, transducer mechanisms and end applications are described and the potential for integration of the materials with ancillary systems components is viewed as an essential consideration. The review concludes with a short discussion of structural polymers that are extending the range of micro-fabrication techniques available to designers and production engineers beyond the limitations of silicon fabrication technology.
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