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Electronics Materials, Packaging and Reliability Techniques (EMPART)
Professor Heli Jantunen, Microelectronics and Materials Physics Laboratories,Department of Electrical and Information Engineering, University of Oulu
Professor Osmo Hormi, Department of Chemistry, University of Oulu
heja(at)ee.oulu.fi, osmo.hormi(at)oulu.fi
http://www.infotech.oulu.fi/empart
Background and Mission
The EMPART (Electronics Materials, Packaging and Reliability Techniques) research group is a multidisciplinary research unit acting mainly within the information technology focus area of the University of Oulu, especially in the electronics, photonics and nanotechnology subfields. The research also has links with biotechnology, the other focus area of the University. The group is a key player in the Micro and Nanotechnology Center of the University of Oulu, where the overall target is to integrate nanostructures enabling novel functionality of electronic, telecommunication, bio/medical and environmental devices.
The group comprises of specialists in microelectronics, materials engineering, measuring techniques, and in chemical and physical sciences, represented by four professors, ten other doctors, including five docents, and 30 doctoral students. The group leaders, Professor Heli Jantunen and Professor Osmo Hormi supervise the postgraduate studies in the group with co-operating professors and docents from the University of Oulu and from the Technical Research Centre of Finland in Oulu (VTT).
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Research integration of the EMPART group. |
The research of the EMPART group was funded by the University of Oulu, the National Technology Agency of Finland (TEKES), the EU, the Academy of Finland, the Nordic Innovation Centre and by national and foreign industry. International research co-operation is a characteristic feature of the EMPART group, with key roles in several projects of the EU Research Programs and Thematic Networks, which are strategically important for European industry. In addition, EMPART is a member of NEXUS (a Network of Excellence in Multifunctional Microsystems), EUSPEN (European Society for Precision Engineering and Nanotechnology) and POLECER (Polar Electroceramics European network organization). The group is also a partner of the EC 6FP Network of Excellence, MIND (Multifunctional & Integrated Piezoelectric Devices) and Patent-DfMM (Design for Micro & Nano Manufacturing).
The overall vision of the EMPART research group is to be an internationally recognized, high excellence research and education unit with significant scientific impact in the fields of micro and nano system technologies. Our ultimate goal is to provide competitive solutions for research and industrial partners via multifunctional applications of novel materials and integration platforms.
During the research year 2007, in accordance with long term research targets, we have continued the integration of interdisciplinary topics towards future advanced device and component implementations. In the following sections, we show examples of applications of new materials and methods in the fields of micro and nanotechnologies. After summarizing the main scientific results, we also describe the most relevant key technologies that represent the bridge between new materials and innovative electrical components/devices.
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Electronics materials – manufacturing – components – characterization: Extrusion/injection moulding, heat treatment, interferometry, laser ablation/deposition, surface probe microscopy and high frequency measurement facilities of our group. |
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Scientific Progress
Reliable Functional Wireless Components and Modules
Novel materials and manufacturing techniques have been key enablers for high performance wireless components and modules in the information technology era. Unique collaboration between component and materials engineers in the group provides immediate implementation of the latest achievements in this field.
Recently, a new ferroelectric barium strontium titanate (BST) thick film paste was developed in the Future active multiband antennas (TAMTAM) Tekes project. Relative permittivity of this novel dielectric material can be adjusted more than 50 % with a static external electric field. Another key feature of the material is a marked decrease in sintering temperature, providing compatibility with low temperature co-fired ceramics (LTCC) material systems. This material has high potential in applications of mass-producible functional wireless components and engineered meta materials. The aim of the TAMTAM project was to improve performance and functionality of mobile phone antennas by using advanced materials, manufacturing, tuning, and electronics packaging technologies. The work was carried out in collaboration with the Telecommunication Laboratory of the University of Oulu. During the year 2007 significant investments in a new antenna measurements system were made.
LTCC technology provides a viable substrate platform for developing future highly-integrated microwave and millimeter-wave System-in-Packages (SiPs) due to its excellent high-frequency materials properties (low loss and dispersion), and its dense 3-D integration and miniaturization capability. To provide high interconnection density and compatibility with automated high-volume SMD assembly, LTCC-SiP modules are soldered to PCBs using ball-grid-array (BGA) or land-grid-array (LGA) interconnection methods. One of the main objectives of the Advanced ceramic modules for RF and Microwave Applications (ACERMI II) Tekes project was to implement low-loss and reliable lead-free solder interconnections for microwave and millimeter-wave LTCC/PWB module assemblies. This research work was done in collaboration with VTT Oulu. The results of both the TAMTAM and ACERMI II projects have been presented in numerous scientific journal articles and at refereed international conferences. 1,4,5,6
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Developed reliable LTCC-BGA module platform for RF and microwave applications. |
Embedded Testing and Prognostic Analysis of Novel Electronic Micromodules
Advances in electronics integration technology are also pushing forward testing techniques. As the wiring density increases and new package types are introduced, more tests per area of the device need to be performed in order to ensure the functionality of the device. The complexity of test methods also increases as the systems become more complex. The testing capability has to be present already at the production phase.
In addition, more attention is given to lifetime monitoring of electronics. In practice this means that during field use, certain critical parts of the system are tested once in a while to ensure their full functionality and to discriminate the possible deviating values that might indicate a forthcoming failure. By mathematically processing the measured values, a prediction of the failure time of a product can be given. It is important to be able to distinguish the deviating values with highest possible accuracy as early as possible, so that lifetime estimations can be made at an early phase. It must be noted that this monitoring should be done without disturbing the operation of the device. Another consideration is how the estimation of the lifetime can be handled in an economic way. One of the significant factors in lifetime estimations is the most cost-effective scheduling of maintenance actions during field usage.
During the field use period of an electronic product, various stresses affect the functionality of the product. Therefore the prognostic methods utilized must be targeted to the real degrading parameters in the product. By monitoring pre-determined parameters related to the most predominant failure mechanism in the product life-cycle, early warning of the failure mechanism can be obtained. Performing prognostic analysis with dedicated failure precursors, directly correlated to the product itself, many advantages can be found, the maintenance effectiveness (and thus cost savings) being the most important one. The prognostic analysis with failure precursors is depicted in the figures below.
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Characteristic precursor monitoring of the micromodules with embedded tests (NOC = number of thermal cycles (left) and data-analysis of the obtained precursors, history data considered, when final failure times were calculated (right). |
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The Remote Access Test Platform (REMTEST) Tekes project, seeks to find the best cost-effective solutions for this so-called prognostic monitoring of structures in field use. The novel methods under present investigation include the monitoring of scattering parameters up to tens of GHz, and resistance bridge -enabled LF monitoring of the structures. These resistance bridges can be embedded in a module, as seen in the figure below.9
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A thick-film embedded LTCC resistor with some of the internal wiring shown. Image was taken before other LTCC tape layers were aligned on the top and the structure laminated and cofired. |
Integrated Actuators, Sensors, Electronics and Functional Composites
The aim of the research work is targeted at integrated low power consumption devices with remote control possibilities. Such devices can be, for example, microwave driven piezoelectric actuators with wireless control. The flexible manufacturing methods developed in the group enable production of customized systems for various industrial and consumer applications such as alarm systems, sensors, switches, pumps and mechanical controller/regulator/tuning devices. For example, piezoelectric actuators embedded in the LTCC have been optimized, showing improved characteristics over the conventional structures, as well as benefits gained from integration. Due to the excellent chemical resistance of the ceramic and the temperature resilient bonding mechanism, such actuators enable operation in harsh environmental conditions. The ATILA and FEMLab software has been effectively employed to optimize various electromechanical structures, e.g. for MEMS devices, interferometer modules and LTCC embedded actuators14.
3D profile and picture of la aser milled key shaped mini mould made on steel. |
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Relative permittivity and losses of 0-3 ceramic composites at 1 GHz and their SEM pictures. |
Piezoactuators on an alumina circuit board and electronic circuit encapsulated by injection molding. |
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Ceramic-polymer composite integrated on LTCC, copper electrode on the composite and measurement schematics up to 14 GHz. |
Integration of electronics components with plastic parts via injection molding is an interesting possibility for added value plastic products. In the Minimi project, funded by Tekes and seven industrial partners, the group has researched, in cooperation with research partners at VTT and the North Karelia University of Applied Sciences, injection molding of plastic miniature parts with micro scale features. The two main subjects of the project are to reveal the limitations of plastic molding and to integrate microelectronics enabling smart plastic devices.
In the Conapo project, funded by Tekes and four industrial partners, the group has researched polymer-ceramic composites with ceramic micro- and nanoparticles. New injection moldable high permittivity and low loss materials for high frequency applications (up 14 GHz) have been developed to be utilized in, for example, RF applications and integrated devices such as antennas, embedded capacitors and circuit boards. 15,16
Innovative products, such as acoustic transducers, pressure and flow sensors, energy harvesters, accelerometers and micropumps, can be developed by combining silicon technology and piezoelectric materials. In the NORD-Pie project, funded by the Nordic Innovations Center – NICe (www.nordicinnovation.net) and project partners, piezoelectric MEMS actuators, sensors and transducers based on chemical solution deposition (CSD) are being developed in co-operation with SINTEF (www.sintef.no/nord-pie) and six industrial partners (from Norway, Iceland, Sweden and Denmark).
Another Nordic co-operation project “Soot sensors for a healthy environment – SootSens”, co-funded by the NICe, Swedish Governmental Agency for Innovation Systems - VINNOVA (www.vinnova.se) and project partners, was started. In the project, innovative multisensing soot sensor systems will be developed in cooperation with four universities and research institutes and three industrial partners.
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Displacement distribution and frequency |
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Displacement distribution of a thin film cantilever resonator under torsion mode modeled with ATILA. |
In the “NOvel SPectroscopic technologies based on Interferometry – NOSPI” project novel interferometer modules are developed with VTT for various spectroscopic applications ranging from low cost to high-end devices. The project is funded by Tekes, VTT and 12 industrial partners.
Basic research on pre-stressed piezoelectric bending actuators was conducted to characterize the physical background of their electrical and electromechanical behavior. Accurate and reliable electromechanical modeling facilitated the design of new actuator structures to improve the displacement capabilities of the bending actuators. Moreover, measurement capabilities were significantly enhanced by purchasing a dual beam Polytec OFV-5000 vibrometer enabling, for example, displacement resolution of picometers, bandwidth up to 10 MHz, real-time displacement and velocity data, surface scanning and dynamic mechanical spectroscopy.
Piezoelectric composites offer advantages over the corresponding ceramic material in terms of flexible manufacturing of 3D structures and costs. Piezoelectric 0-3 ceramic-polymer composites were developed to be utilized as integrated actuators and sensors. Electrical and electromechanical properties of the composites with various different ceramic loadings were characterized in order to maximize the piezoelectric effects.
Piezoactuators with multiple pre-stressed regions were realized and characterized to enable actuator and sensor matrices and motors. Laser micro-machined structurally graded monolithic benders were also realized to research the effect of the non-uniform electric field and strain distribution, and the relation between actuator geometry, stiffness and pre-stress. The research facilitates ceramic MEMS development, enhancement of displacement capabilities of benders and a better understanding of the mechanisms affecting different actuator structures. In addition, a piezoelectric valve on LTCC substrate for the regulation of gas and liquid transport was realized in cooperation with Wroclaw University, Poland.
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Surface profile and pictures of pre-stressed actuators with multiple active regions on disc. A laser machined monolithic piezoelectric bender with structural gradients and its displacement. |
An electronic interface for resistor based sensor systems (e.g. pressure sensor based on piezoresistors) was developed using digital potentiometers. The novel approach offers an auto-calibration possibility in order to negate the effect of the manufacturing tolerances, temperature, humidity, creep or aging. In addition, effective resolution or bits of the sensors are improved by more accurate balancing of the resistor bridge. The theoretical background and quality rules for the designing of the proposed bridge configuration were also established.13 In addition, research on integrated actuator sensor structures was continued by realizing a piezoelectric bender actuator and capacitive measurement system with oscillator circuitry on the same platform. The system exhibited a displacement resolution of up to 10 nm while the noise level of the electronics can be further decreased to obtain higher resolution.
Organic Compounds for Optical Applications
OLEDs research focuses on the production of organic compounds which can be used in applications such as liquid crystalline displays and /or thin flexible displays (TV screens, computer screens, mobile phones, etc.)
In 2007, the group has succeeded in synthesizing new compounds applicable to ligands in photoluminescent and electroluminescent materials. A series of 4-alkoxy-8-hydroxyquinolines and Al complexes of them were prepared. Figure (a) shows the photoluminescence behavior of Al tris (4-methoxy-8-hydroxyquinoline), Al tris (4-butoxy-8-hydroxyquinoline) and the parent Alq3. In co-operation with VTT Oulu, OLEDs have been prepared from Al tris (4-butoxy-8-hydroxyquinoline) and Alq3 by using spin coating techniques (Figure b). Figure (c) shows the EL characteristics of the OLEDs.25,26
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(a) PL spectrum from Alq3 (green line)Al tris (4-butoxy-8-hydroxyquinoline) (blue line) and Al tris (4-methoxy-8-hydroxyquinoline) (red line), (b) OLEDs from Alq3 (green color), Al tris (4-butoxy-8-hydroxyquinoline (blue color) and (c) The normalized EL spectrum for parent Alq3 (red line) and Al tris (4-butoxy-8-hydroxyquiniline) (black line). |
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The group has also prepared 8-hydroxyquinoline derivatives with various amino and thioalkyl functionalities at position-4.
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(a) the PL spectrum of the parent Alq3 (green line) and Al tris (4-piperidinyl-8 hydroxyquinoline) (blue line), (b) The PL emission colour of Al tris (4-piperidinyl-8-hydroxyquinoline) in CHCl3 solution, (c) The chemical structure of the same complex. |
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Carbon Nanotube Research
Nanotechnology requires collaboration of researchers from different disciplines: chemists, physicists and engineers. The research topics include synthesis and application of nano-porous silicon/alumina structures, assemblies based on carbon nanotube thin and thick films, and nanofabrication/integration technologies. The main goal is synthesis and integration of nanomaterials and structures that are used in advanced electronic applications such as fuel cells, printed transistors, sensors, components for thermal management and flexible contacts - thus nanotechnology is foreseen as an important emerging field of future research and development. As an example of our nanotechnology activities, we show some of our recent results in carbon nanotube research.
Magnetic field induced efficient alignment of carbon nanotubes in aqueous solutions. Efficient alignment of aqueous carboxyl functionalized multi-walled carbon nanotubes having remnant iron catalyst particles is carried out in low external magnetic-fields (B = 1 T). The nanotubes were grown by catalytic chemical vapor deposition, and then functionalized in a multi-step oxidation process using nitric acid and potassium permanganate. In the field-induced ordering, the ferromagnetic property of iron nanoparticles entrapped in the inner-tubular cavity of nanotubes is exploited.27
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(a) Field dependence of magnetization M(H) of acid-treated nanotubes measured at 5 and 300 K. (b) FESEM image of a nanotube film aligned in a magnetic field. (c) EFTEM image of carboxyl functionalized MWCNTs. The black arrows show catalyst nanoparticles entrapped in the inner tubular cavity of nanotubes. |
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Cooling with integrated carbon nanotube films. We continued our previous efforts in thermal management with carbon nanotubes integrated on electronic devices. The thermal interface between the component and cooler turned out to be a serious concern when solder mounted coolers were applied. To improve the thermal interface and thus heat dissipation from a hot device, we grew CNTs directly on the component. In this way, a 100% improvement in heat dissipation could be achieved, even in conditions of normal convection (i.e. no forced coolant flow is applied). 28,29
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Demonstration of efficient heat dissipation (improvement with a factor of ~2) with carbon nanotubes grown directly on a device (Pt wire coated with SiO2). a, Optical image of two Pt wires of 25.4 µm diameter and ~16 mm length. Both wires are coated with PECVD grown SiO2 (Pt/SiO2), but the lower one is equipped with MWCNTs of ~500 µm length (Pt/SiO2/MWCNTs) grown directly on the SiO2 coating (scale 3 mm). b, Schematic drawing of the two types of wires. c, Temperature vs. power plots for the Pt/SiO2 and Pt/SiO2/MWCNTs wires having R0 resistances (Pt core) of 3.73 W and 3.48 W, respectively (inset: FESEM image of CNT bundles grown directly on the SiO2 coated Pt wire (scale 500 µm.) |
Nitric oxide gas sensors with functionalized carbon nanotubes. Nitric oxide (NO) gas sensing with carboxyl functionalized single- and multi-walled carbon nanotubes (SWCNTs and MWCNTs) is demonstrated. Stable solutions of the carboxylated nanotubes were made, and then drop-cast on thick film gold electrodes on alumina substrates. The resistive nanotube sensors obtained were tested in a 2-point setup at different temperatures, and NO gas concentrations of up to 100 ppm in synthetic air, and also in argon buffer. When exposed to NO, the conductivity of the sensors changed by up to ~40% for SWCNTs and ~12% for MWCNTs; however, in the investigated regime, the response was found to be fairly independent of NO concentration. Though all sensors showed practically instantaneous gas response, the time needed for saturation (a few tens of minutes) was found to be concentration dependent. 30
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Gas sensor with thick film gold electrodes (front side) and integrated platinum heater (back side). FESEM images of drop-cast carbon nanotube gas sensing layers deposited on the thick-film electrode structure (right panel). The upper images show the tangled network of MWCNTs on a gold electrode (left) and on the alumina surface between the electrodes (right). Inset: edge of sensor electrode. In the lower panel, a sensor made of SWCNTs is shown. |
Inkjet printing of transparent and conductive patterns of single-walled carbon nanotubes and PEDOT-PSS composites. Transparent and conductive patterns of carboxyl functionalized single-walled carbon nanotubes (SWCNT-COOHs) and their composites with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) were deposited on various substrates by inkjet printing. For low print repetitions, the PEDOT-PSS/SWCNT-COOH composite patterns show enhanced conductance as compared to the corresponding PEDOT-PSS films. The results suggest a decreased percolation threshold for the printed composite since the nanotubes establish electrical interconnections between the separate PEDOT-PSS (conductive phase) islands being dispersed in the PSS-phase. However, the interaction between PEDOT-PSS and SWCNTs becomes insignificant, and the conductivity is not enhanced by the nanotubes, when the amount of PEDOT-PSS is sufficient to form a continuous conducting phase. Up to now, patterns having sheet resistivities as low as ~1 kOhm/square could be achieved. Though there is a trade-off between transparency and conductivity – we achieved highly transparent patterns (~ 90%) with a reasonably low resistivity of ~ kOhm/square. The ink and printing method proposed here offers new alternatives of conventional transparent conductive materials based on either polymers or indium oxides; they offer scalable production of cost-effective transparent electronics.32
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Sheet resistivity vs. optical transmittance of polymer and nanotube-polymer composite patterns printed on PET. In the right panel, a printed film is connected in series with a green light-emitting diode (LED) and placed between the LED and camera (resistivity ~2.6 kOhm/square with corresponding transparencies of ~82% @ 400 nm and ~26% @ 2500 nm as shown by the arrows in the left panel). |
A complete technology protocol to synthesize highly ordered carbon nanotube architectures in a silicon environment has been established by our group in collaboration with the Micro and Nanotechnology Center. Nanotube research fostered related projects by which a network of national and international collaborating laboratories was successfully established and further funding was acquired for applied research, such as:
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Integrated self-adjusting nanoelectronic sensors (2006-2009, EU)
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Hydrogen production for fuel cells by bioethanol reforming (2007-2008, TEKES)
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Industrially relevant, novel reaction routes for catalytic transformation of renewable biomaterials (2007-2010, TEKES)
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Nanomaterials in printable electronics RFID solutions (2005-2008, TEKES)
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New, innovative sustainable transportation fuels for mobile applications: from biocomponents to flexible liquid fuels (2007-2010, the Academy of Finland)
Microfabrication Technologies: From Materials to Devices
To be able to implement novel materials developed by our group, a number of different processing methods are used. The research described in the section “Scientific Progress” was accomplished mainly using the facilities of the Microelectronics and Materials Physics Laboratories and the Micro and Nanotechnology Centre of the University of Oulu. The techniques combine processing of robust ceramic modules (LTCC line, laser fabrication, thick film printing), fabrication of Si wafers/chips, moulding of polymers and various composite materials, mounting macroscopic films of nanostructured materials, inkjet printing of nanoparticles and pulsed laser deposition of nanostructured thin films. Next, examples of key processes are shown.
The LTCC line. Utilizing the LTCC prototype manufacturing and sample production line, the EMPART group is able to offer an attractive platform for customized RF and microwave applications, as well as electronics micromodules. Potential support in the fields of mobile communications, wireless, automotive, sensor technology, space and various consumer products is enabled. The transition from research to the prototype/final product is assisted by close co-operation with materials suppliers. In addition, the LTCC process team is composed of experienced researchers capable of designing, modeling and developing novel customized/engineered LTCC materials and processes. Recently developed LTCC materials can perform ferroelectric, varistor, piezoelectric and dielectric functions and they are prepared in tape or paste forms.
The group does also computer-aided component design and modeling with tools like HFSS, ATILA, FEMLab and Sonnet. With laser-aided micromachining, cavities, channels and vias are also made inside LTCC modules. Final testing/characterization and post-processing such as surface mount techniques, wire bonding and dicing complete the prototype service.
Laser-assisted surface processing. When rapid maskless laser processing with an accuracy of a few micrometers is aimed for, pulsed solid state lasers (Q-switched Nd:YAG, Nd:YVO4, Er3+:YAG, Ti:Saphire) equipped with harmonic frequency generating optics (non-linear optical crystals) give the best results. Our group has at its disposal a diode pumped high-performance frequency-tripled neodymium-doped yttrium vanadate laser system (Siemens, Microbeam 3200 model, 3w Nd:YVO4 , l = 355 nm, P = 0.2 - 3.2 W, t = 30 ns, f = 20 - 100 kHz, w0 ~15 µm, scan rate up to 2000 mm/s, work table 610 × 710 mm2, accuracy 1 µm in the galvanometric scan field of 50 × 50 mm2).
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Laser processing with Siemens Microbeam 3200 model. |
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Due to the short wavelength (UV, 355 nm) and short pulse duration (30 ns), the laser-matter interaction is rather photolytic than thermal, which makes the materials processing “clean”, avoiding thermal reactions (oxidation, re-crystallization, crack formations) in the processed materials and resulting in a very precise machining of most materials used in microelectronics. The high pulse repetition rate, high average power and the fast scanning capabilities enable extremely fast maskless materials processing (e.g. in a PCB having 65 µm RCC and 12 µm Cu layers ~200 pieces of micro-vias can be drilled within a second). The controlling software enables fine tuning of materials processing parameters. The different sequential process tool options provide excellent opportunities to structure/cut/drill/modify a large variety of single and multilayer materials. The files containing the patterns can be made using any CAD software.
Injection molding and mixing extrusion. Development of new polymer based functional composite materials by mixing extruder, integration of electronic components with plastic parts via injection molding and combining these two processes offer attractive possibilities for numerous applications and material innovations. Injection moulding enables a cost effective manufacturing method for 3D structures, while the properties of ceramic-polymer composites, for example, can be seamlessly adjusted, filling the gap of properties between polymer and ceramic. The group uses a laboratory-scale Haake Minijet injection moulding unit and a Haake Minilab mixing extruder with co-rotating or counter rotating screws and mixing chamber specially designed for abrasive materials.
National and International Co-operation
The EMPART research group co-operated in the form of common research projects with other Infotech Oulu research groups, mainly with OPME (Optoelectronics and Measurement Unit) and CAS (Circuits and Systems Group). OPME and EMPART together with VTT have funding through the Finland Distinguished Professor Programme for Professor Ghassan Jabbour (Arizona State University), who established The Center for Nano Organic and Hybrid Electronics and Photonics during the year 2007.
National and international research co-operation in the form of common projects, scientific publications or student, researcher and lecturer exchange with the following partners has been carried out: VTT, Finland; Helsinki University of Technology, Helsinki, Finland; ORC Tampere University of Technology, Tampere, Finland; University of Joensuu, Joensuu, Finland; Åbo Akademi, Turku, Finland; North Karelia University of Applied Sciences, Joensuu, Finland; Kemi-Tornio University of Applied Sciences, Kemi, Finland; Technical University of Ilmenau, Ilmenau, Germany; Technical University of Luleå, Luleå, Sweden; Regional Research Laboratory, Thiruvananthapuram, India; Yonsei University, Soul, Korea; University of Birmingham, Birmingham, UK; EPFL, Lausanne, Switzerland; SINTEF, Oslo, Norway; Chalmers University of Technology, Gothenburg, Sweden; Advanced Technology Institute, University of Surrey, UK; Jozef Stefan Institute, Ljubljana, Slovenia; Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic; Wroclaw University of Technology, Wroclaw, Poland; St. Petersburg Electrotechnical University, St. Petersburg, Russia; Royal Institute of Technology, Stockholm, Sweden; Rensselaer Polytechnic Institute, Troy, NY, USA; University of Szeged, Budapest, Hungary; Linköping University, Linköping, Sweden; Lund University, Lund, Sweden; University of Iasi, Iasi, Romania.
The EMPART research group also acknowledges Finnish and foreign industrial partners for their active participation in research projects, as well as the Academy of Finland, Tekes, the EU, the Nordic Innovation Centre and the University of Oulu for financial support.
Exploitation of Results
Materials, components and technologies developed by the group are widely applied in the national electronics industry, especially in the mobile phone industry. LTCC micromodules for telecommunication applications and ceramic MEMS modules must be mentioned as examples of present exploitation. In 2007, emphasis has been laid on a continuous extension of our recent scientific achievements also in the field of nanotechnology with integrated nanostructured assemblies for electronics, biotechnology/medicine, photonics, and catalyst systems. Additionally, several novel materials and material systems recently developed, as well as the progress in fabrication, have been utilized in antennas, multichip modules, ceramic/polymer integrations, filters, micropumps etc.
Personnel
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professors & doctors |
14 |
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graduate students |
32 |
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others |
1 |
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total |
47 |
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person years |
25 |
External Funding
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Source |
EUR |
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Academy of Finland |
185 000 |
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Ministry of Education |
155 000 |
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Tekes |
895 000 |
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domestic private |
126 000 |
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EU + other international |
350 000 |
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total |
1 731 000 |
Doctoral Theses
Tóth G (2007) Computer modeling supported fabrication processes for electronics applications.
Selected Publications
Komulainen M, Mähönen J, Tick T, Berg M, Jantunen H, Henry M, Free C & Salonen E (2007) Embedded air cavity backed microstrip antenna on an LTCC substrate. Journal of the European Ceramic Society 27(8-9): 2881-2885.1
Komulainen M, Berg M, Jantunen H & Salonen E (2007) Compact varactor-tuned meander line monopole antenna for DVB-H signal reception. IEE Electronics Letters 43(24): 1324-1326.2
Komulainen M, Palukuru VK & Jantunen H (2007) Frequency tunable dual-band planar inverted-F antenna based on a switchable paracitic element. FREQUENZ - Journal of RF-Engineering and Telecommunications 61(9-10): 207-212.3
Nousiainen O, Putaala J, Kangasvieri T, Rautioaho R & Vähäkangas J (2007) Failure mechanisms of thermomechanically loaded SnAgCu/plastic core solder ball composite joints in low-temperature co-fired ceramic/printed wiring board assemblies. Journal of Electronic Materials 36(3): 232-241.4
Kangasvieri T, Halme J, Vähäkangas J & Lahti M (2007) High-performance vertical transition for broadband millimetre-wave BGA module packaging. Electronics Letters 43(11): 638-639.5
Nousiainen O, Kangasvieri T, Rönkä K, Rautioaho R & Vähäkangas J (2007) Interfacial reactions between Sn-based solders and AgPt thick film metallizations on LTCC. Soldering & Surface Mount Technology 19(3): 15-25.6
Saikkonen T & Moilanen M (2007) Component value calculations and characterizations for measurements in the IEEE 1149.4 environment. Journal of Electronic Testing - Theory and Applications 23(6): 569-579.7
Hannu J & Moilanen M, Methods of testing discrete semiconductors in the 1149.4 environment. Journal of Electronic Testing - Theory and Applications 23(6): 581-592.8
Voutilainen J, Putaala J, Moilanen M & Jantunen H (2008) A prognostic method for the embedded failure monitoring of solder interconnections with 1149.4 test bus architecture. Microelectronics Journal.9
Lahti M, Vimpari A & Kautio K (2007) Printable resistors in LTCC systems. Journal of European Ceramic Society 27(8-9): 2953-2956.10
Heikkinen V, Alajoki T, Juntunen E, Karppinen M, Kautio K, Mäkinen J-T, Ollila J, Tanskanen A, Toivonen J, Casey R, Scott S, Pintzka W, Theriault S & McKenzie I (2007) Fiber-optic transceiver module for high-speed intrasatellite. Journal of Lightwave Technology 25(5): 1213-1223.11
Heikkinen V, Juntunen E, Kautio K, Kemppainen A, Korhonen P, Ollila J, Sitomaniemi A, Kemppainen T, Kutilainen T & Sahavirta H (2007) High-brightness LED modules on alumina substrates. Advancing Microelectronics 34(4): 12-16.12
Leinonen M, Juuti J & Jantunen H (2007) Interface circuit for resistive sensors utilizing digital potentiometers. Sensors and Actuators A 138(1): 97-104.13
Heinonen E, Juuti J & Jantunen H (2007) Characteristics of piezoelectric cantilevers embedded in LTCC. Journal of European Ceramic Society 27(13-15): 4135-4138.14
Hu T, Juuti J & Jantunen H (2007) RF properties of BST-PPS composites. Journal of European Ceramic Society 27(8-9): 2923-2926.15
Hu T, Juuti J, Jantunen H & Vilkman T (2007) Dielectric properties of BST/polymer composite. Journal of the European Ceramic Society 27(13-15): 3997-4001.16
Honkamo J, Hannu J, Jantunen H, Moilanen M & Mielcarek W (2007) Microstructural and electrical properties of multicomponent varistor ceramics with PbO-ZnO-B2O3 glass addition. Journal of Electroceramics 18(3-4): 175-181.17
Sebastian MT, Uusimäki A & Jantunen H (2007) Editorial Journal of the European Ceramic Society 27(8-9): 2745.18
Pudas M, Viollet S, Ruffier F, Kruusing A, Amic S, Leppävuori S & Franceschini N (2007) A miniature bio-inspired optic flow sensor based on low temperature co-fired ceramics (LTCC) technology. Sensor and Actuators A 133(1): 88-95.19
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Fan J, Leppävuori S, Luusua I, Henttinen K, Eränen S, Hietanen I & Juntunen M (2008) Fabrication of silicon based through-wafer interconnects for advanced chip scale packaging. Sensors and Actuators A 142(1): 405-412.23
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Kordás K, Mustonen T, Tóth G, Vähäkangas J, Uusimäki A, Jantunen H, Gupta A, Rao KV, Vajtai R & Ajayan PM (2007) Magnetic-field induced efficient alignment of carbon nanotubes in aqueous solutions. Chemistry of Materials 19(4): 787-791.27
Kordás K, Tóth G, Moilanen P, Kumpumäki M, Vähäkangas J, Uusimäki A, Vajtai R & Ajayan PM (2007) Chip cooling with integrated carbon nanotube microfin architectures. Applied Physics Letters 90: 123105.28
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Mäklin J, Mustonen T, Kordás K, Saukko S & Vähäkangas J (2007) Nitric oxide gas sensors with functionalized carbon nanotubes. Physica Status Solidi B 244(11): 4298-4302.30
Mustonen T, Kordás K, Saukko S, Tóth G, Penttilä JS, Helistö P, Seppä H & Jantunen H (2007) Inkjet printing of transparent and conductive patterns of single-walled carbon nanotubes and PEDOT-PSS composites. Physica Status Solidi B 244 (11): 4336-4340.31
Mikkola J-PT, Virtanen PP, Kordás K, Karhu H & Salmi TO (2007) SILCA - Supported ionic liquid catalysts for fine chemicals. Applied Catalysis A 328(1): 68-76.32
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Tyunina M, Levoska J & Jaakola I (2007) Dynamic disorder in BaTiO3 epitaxial films. Physical Review B 75: 140102(R).34
Tyunina M & Levoska J (2007) The paraelectric state in thin-film (Ba,Sr)TiO3. Journal of Applied Physics 101: 084119.35
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Kamba S, Nuzhnyy D, Veljko S, Bovtun V, Petzelt J, Wang YL, Setter N, Levoska J, Tyunina M, Macutkevic J & Banys J (2007) Dielectric relaxation and polar phonon softening in relaxor ferroelectric PbMg1/3Ta2/3 O3. Journal of Applied Physics 102: 074106.37
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