SCEE 2008 book of abstracts : the 7th International Conference on Scientific Computing in Electrical Engineering (SCEE 2008), September 28 – October 3, 2008, Helsinki University of Technology, Espoo, Finland

This report contains abstracts of presentations given at the SCEE 2008 conference.reviewe

INTEGRATION OF CMOS TECHNOLOGY INTO LAB-ON-CHIP SYSTEMS APPLIED TO THE DEVELOPMENT OF A BIOELECTRONIC NOSE

This work addresses the development of a lab-on-a-chip (LOC) system for olfactory sensing. The method of sensing employed is cell-based, utilizing living cells to sense stimuli that are otherwise not easily sensed using conventional transduction techniques. Cells have evolved over millions of years to be exquisitely sensitive to their environment, with certain types of cells producing electrical signals in response to stimuli. The core device that is introduced here is comprised of living olfactory sensory neurons (OSNs) on top of a complementary metal-oxide-semiconductor (CMOS) integrated circuit (IC). This hybrid bioelectronic approach to sensing leverages the sensitivity of OSNs with the electronic signal processing capability of modern ICs. Intimately combining electronics with biology presents a number of unique challenges to integration that arise from the disparate requirements of the two separate domains. Fundamentally the obstacles arise from the facts that electronic devices are designed to work in dry environments while biology requires not only a wet environment, but also one that is precisely controlled and non-toxic. Design and modeling of such heterogeneously integrated systems is complicated by the lack of tools that can address the multiple domains and techniques required for integration, namely IC design, fluidics, packaging, and microfabrication, and cell culture. There also arises the issue of how to handle the vast amount of data that can be generated by such systems, and specifically how to efficiently identify signals of interest and communicate them off-chip. The primary contributions of this work are the development of a new packaging scheme for integration of CMOS ICs into fluidic LOC systems, a methodology for cross-coupled multi-domain iterative modeling of heterogeneously integrated systems, demonstration of a proof-of-concept bioelectronic olfactory sensor, and a novel event-based technique to minimize the bandwidth required to communicate the information contained in bio-potential signals produced by dense arrays of electrically active cells

3D Structuration Techniques of LTCC for Microsystems Applications

This thesis aimed at developing new 3D structuration techniques for a relatively recent new ceramic technology called LTCC, which stands for Low Temperature, Co-fired Ceramic. It is a material originally developed for the microelectronic packaging industry; its chemical and thermal stabilities make it suitable to military-grade and automotive applications, such as car ignition systems and Wi-Fi antennae (GHz frequencies). In recent years however, the research in ceramic microsystems has seen a growing interest for microfluidics, packaging, MEMS and sensors. Positioned at the crossing of classical thick-film technology on alumina substrate and of high temperature ceramics, this new kind of easily structurable ceramic is filling the technological and dimensional gap between microsystems in Silicon and classical "macro microsystems", in the sense that we can now structure microdevices in the range from 150 mm to 150 mm. In effect, LTCC technology allows printing conductors and other inks from 30 mm to many mm, structuration from 150 mm to 150 mm, and suspended structures with gaps down to 30 mm thanks to sacrificial materials. Sensors and their packaging are now merged in what we can call "functional packaging". The contributions of this thesis lie both in the technological aspects we brought, and in the innovative microfluidic sensors and devices created using our developed methods. These realizations would not have been possible with the standard lamination and firing techniques used so far. Hence, we allow circumventing the problems related to microfluidics circuitry: for instance, the difficulty to control final fired dimensions, the burden to produce cavities or open structures and the associated delaminations of tapes, and the absence of "recipe" for the industrialization of fluidic devices. The achievements of the presented research can be summarized as follows: The control of final dimensions is mastered after having studied the influence of lamination parameters, proving they have a considerable impact. It is now possible to have a set of design rules for a given material, deviating from suppliers' recommendations for the manufacture of slender structures requiring reduced lamination. A new lamination method was set up, permitting the assembly of complex microfluidic circuits that would normally not sustain standard lamination. The method is based on partial pseudo-isostatic sub-laminations, with the help of a constrained rubber, subsequently consolidated together with a final standard uniaxial lamination. The conflict between well bonded tapes and acceptable output geometry is greatly attenuated. We achieved the formulation of a new class of Sacrificial Volume Materials (SVM) to allow the fabrication of open structures on LTCC and on standard alumina substrates; these are indeed screen-printable inks made by mixing together mineral compounds, a glassy phase and experimental organic binders. This is an appreciable improvement over the so-far existing SVMs for LTCC, limited to closed structures such as thin membranes. An innovative industrial-grade potentially low-cost diagnostics multisensor for the pneumatic industry was developed, allowing the measurement of compressed air pressure, flow and temperature. The device is entirely mounted by soldering onto an electro-fluidic platform, de facto making it a true electro-fluidic SMD component in itself. It comprises additionally its own integrated SMD electronics, and thanks to standard hybrid assembly techniques, gets rid of external wires and tubings – this prowess was never achieved before. This opens the way for in situ diagnostics of industrial systems through the use of low-cost integrated sensors that directly output conditioned signals. In addition to the abovementioned developments, we propose an extensive review of existing Sacrificial Volume Materials, and we present numerous applications of LTCC to sensors and microsystems, such as capacitive microforce sensors, a chemical microreactor and microthrusters. In conclusion, LTCC is a technology adapted to the industrial production of microfluidic sensors and devices: the fabrication steps are all industrializable, with an easy transition from prototyping to mass production. Nonetheless, the structuration of channels, cavities and membranes obey complex rules; it is for the moment not yet possible to choose with accuracy the right manufacturing parameters without testing. Consequently, thorough engineering and mastering of the know-how of the whole manufacturing process is still necessary to produce efficient LTCC electro-fluidic circuits, in contrast with older techniques such as classical thick-film technology on alumina substrates or PCBs in FR-4. Notwithstanding its lack of maturity, the still young LTCC technology is promising in both the microelectronics and microfluidics domains. Engineers have a better understanding of the structuration possibilities, of the implications of lamination, and of the most common problems; they have now all the tools in hand to create complex microfluidics circuits

CIM: Revolution in Progress (Proceedings of the Final IIASA Conference on Computer Integrated Manufacturing: Technologies, Organizations and People in Transition)

The Final Conference of the IIASA Project on Computer Integrated Manufacturing was held at the headquarters of IIASA in Laxenburg, Austria, on July 1-4, 1990. The Conference itself was co-sponsored by the Ford and Alfred P. Sloan Foundations, though much of the earlier research work owes its existence to funding by the Finnish Sitra Organization and the American National Science Foundation. In addition to these primary funders, much of the work carried out by individual researchers was funded by their own governments, research institutes, etc., this included major inputs from Japan and Czechoslovakia. The aim of the research was to examine CIM from various perspectives including: technological characteristics, the diffusion process, managerial and organizational aspects, and the social and economic implications. The Conference was attended by 105 people from 22 countries, including representatives from the OECD, UNIDO, the ECE, and the ILO. Of these participants 28 came from Eastern Europe and the rest from Japan or Western countries. This Volume contains selected papers presented at the Conference, and transcripts of key parts of the policy discussion. The papers are organized in the following way: Part 1. Overviews; Part 2. Strategies and Models for CIM; Part 3. CIM Diffusion Studies; Part 4. CIM Technologies; Part 5. Organizational and Social Impacts; Part 6. Keynote Policy Panel Discussion; Part 7. CIM Implications for Industry and Government

High frequency signal integrity in high-density assemblies

The demand for faster, portable and reliable electronic devices is increasing the pressure on the development of assembly techniques for signal integrity (SI). The advance of integrated circuits toward a large number of Input/Output (I/Os), a high number of operations and up to microwave communication frequencies, is behind the drive for the search for new packaging solutions. The materials and assembly techniques have an important impact on the propagation of high speed signals. Signal integrity issues emerge due to the electrical losses of materials, reflections from impedance discontinuities in the signal path and fast transitions of the signals. For these reasons, signal integrity in lead-free connections of WLCSP, flip chip (FC) and Integrated Module Board (IMB) assemblies were investigated up to 50 GHz. The increase of conductor loss resulting from the presence of thick oxide layers on the surface of solder bumps of hot running components was experimentally studied for the first time. Utilizing theoretical calculations, a design rule was developed to account for the 40 % increase in losses due to the presence of oxide layers at high frequencies. The research into the influence of solder microstructure on signal quality showed that it did not negatively affect the wave propagation. Experimental results proved that the presence of underfills and high density routing on printed wiring boards (PWBs) under the WLCSP components, detuned the components and the connections. The effects of three different underfills on signal propagation were studied. It was proven that the changes resulting from the rheology and parameters of curing process influence the losses and reflections of circuits. The analysis of microwave performances of flip chip (FC) and Integrated Module Board (IMB) assembly techniques demonstrated that they are well suited to Radio frequency (RF) and high speed applications. Comparison showed that IMB performed better as the wave encountered smaller discontinuities and had an optimized propagation path. Full wave simulations of IMB assemblies were performed considering finite ground coplanar waveguide (FGCPW), microstrip and stripline connections with stack-ups that included high dielectric constant materials and four connection possibilities. The research was carried out in the domains of both frequency and time to rigorously determine the sources of signal reflections. The results emphasized that in the design for match impedance and optimal current return path, discontinuities and reference planes had significant impact on signal integrity

Microelectromechanical Systems and Devices

The advances of microelectromechanical systems (MEMS) and devices have been instrumental in the demonstration of new devices and applications, and even in the creation of new fields of research and development: bioMEMS, actuators, microfluidic devices, RF and optical MEMS. Experience indicates a need for MEMS book covering these materials as well as the most important process steps in bulk micro-machining and modeling. We are very pleased to present this book that contains 18 chapters, written by the experts in the field of MEMS. These chapters are groups into four broad sections of BioMEMS Devices, MEMS characterization and micromachining, RF and Optical MEMS, and MEMS based Actuators. The book starts with the emerging field of bioMEMS, including MEMS coil for retinal prostheses, DNA extraction by micro/bio-fluidics devices and acoustic biosensors. MEMS characterization, micromachining, macromodels, RF and Optical MEMS switches are discussed in next sections. The book concludes with the emphasis on MEMS based actuators