Chip integration using inkjet-printed silver conductive tracks reinforced by electroless plating for flexible board packages

International audienceInkjet-printing of interconnects is a maskless technology that has attracted great interest for printed electronics and packaging applications. Gemalto is expecting by motivated and developing skills and knowledge in this area to be at the forefront of European Security innovation and to answer to a continuous market pressure for higher security, lower cost and more secure complex systems. With an increasing need for flexible and mass deliveries of advanced secure personal devices such as: electronic passports, ID cards, driver licenses, other smartcards, e-documents and tokens. EMSE is seeing in these new developments an exciting brand new area of research situated between material science and electronics. In this frame, deposit and pattern creation for chip interconnection require specific behaviors which have to be scientifically understood to pursue industrial harmonious implementation. Both groups collaborated on inkjet-printed electronic routing from deposition to sintering and characterization, using collaborative means provided on Micro-PackS platform

Nanoporous Gold Characterization, Structural Modification and Use as a Solid Support for Biomolecule Immobilization

Nanoporous gold (NPG) has immense technological applications owing to a plethora of properties like large surface area to volume ratio, plasmonic properties, stable gold-thiolate bond formation and a wide range of pore sizes. The surface morphology of nanoporous gold has been altered previously by dealloying and thermal annealing to increase/decrease the pore size and change the surface area. We provide a novel electrochemical annealing technique for post dealloying modification wherein electrochemical sweep cycles in different electrolytes at positive potentials leads to a subsequent increase in pore sizes of nanoporous gold as studied using scanning electron microscopy. Tailoring the surface of nanoporous gold allows us to characterize and study self-assembled monolayers of alkanethiols, including those terminated by carbohydrate moieties. The orientation of these thiols on nanoporous gold is not uniform due to the interconnected framework of pores and ligaments and we try to offer a fair comparison between flat gold and nanoporous gold to determine the surface coverage of these self-assembled monolayers. Carbohydrate-lectin interactions have been studied with the help of dendrimers as linkers. Dendrimers (polyamidoamine generation 4 and 5) have been used as linkers due to their multivalent interactions with carbohydrate moieties and impedance spectroscopy as well as atomic force microscopy techniques have been utilized to study dendrimers attached on nanoporous gold surface using covalent immobilization. This study aims at providing a comprehensive surface property analysis of nanoporous gold

高効率LEDに向けた高品質GaNテンプレートに関する研究

早大学位記番号:新7544早稲田大

Nanowires for 3d silicon interconnection – low temperature compliant nanowire-polymer film for z-axis interconnect

Semiconductor chip packaging has evolved from single chip packaging to 3D heterogeneous system integration using multichip stacking in a single module. One of the key challenges in 3D integration is the high density interconnects that need to be formed between the chips with through-silicon-vias (TSVs) and inter-chip interconnects. Anisotropic Conductive Film (ACF) technology is one of the low-temperature, fine-pitch interconnect method, which has been considered as a potential replacement for solder interconnects in line with continuous scaling of the interconnects in the IC industry. However, the conventional ACF materials are facing challenges to accommodate the reduced pad and pitch size due to the micro-size particles and the particle agglomeration issue. A new interconnect material - Nanowire Anisotropic Conductive Film (NW-ACF), composed of high density copper nanowires of ~ 200 nm diameter and 10-30 µm length that are vertically distributed in a polymeric template, is developed in this work to tackle the constrains of the conventional ACFs and serves as an inter-chip interconnect solution for potential three-dimensional (3D) applications

Nanoenabling electrochemical sensors for life sciences applications

Electrochemical sensing systems are advancing into a wide range of new applications, moving from the traditional lab environment into disposable devices and systems, enabling real-time continuous monitoring of complex media. This transition presents numerous challenges ranging from issues such as sensitivity and dynamic range, to autocalibration and antifouling, to enabling multiparameter analyte and biomarker detection from an array of nanosensors within a miniaturized form factor. New materials are required not only to address these challenges, but also to facilitate new manufacturing processes for integrated electrochemical systems. This paper examines the recent advances in the instrumentation, sensor architectures, and sensor materials in the context of developing the next generation of nanoenabled electrochemical sensors for life sciences applications, and identifies the most promising solutions based on selected well established application exemplars

Gallium-based Solid Liquid Interdiffusion Bonding of Semiconductor Substrates near room temperature

Within this work, bonding technologies based upon the alloying of gallium with other metals to assemble semiconductor substrates for the possible application of encapsulation and 3D-integration of micro systems and devices have been researched. Motivated by the important demand to achieve low temperature processes, methods with bonding temperatures below 200°C were investigated. Necessary technologies like the deposition of gallium as thin film and subsequent micro structuring have been developed. The alloying between gallium and gold as well as gallium and copper was analysed in detail. A good correlation between the elemental composition of the interface and its mechanical and electrical parameters was established, particularly regarding its thermal dependence. It emerged that in case of combination Au/Ga Kirkendall void are extensively formed whereby serious problems with mechanical strength as well as hermeticity emerged. In case of Cu/Ga, this problem is existent to a much lesser degree; it was possible to create hermetic tight bonds. For the necessary pre-treatment of copper, several methods could be successfully demonstrated. In summary, the development of bonding technologies based upon metallic interfaces that exhibit electric conductance, high strength and hermetic seal could be demonstrated.In dieser Arbeit werden Bondverfahren zum Fügen von Halbleitersubstraten für mögliche Anwendungen für die Verkapselung und 3D-Integration von Bauelementen der Mikrosystemtechnik erforscht, die auf der Legierungsbildung von Gallium mit anderen Metallen beruhen. Motiviert von der zentralen Anforderung an niedrige Prozesstemperaturen wurden Methoden mit Fügetemperaturen deutlich unter 200°C untersucht. Dafür nötige Technologien zum Abscheiden von Gallium als Dünnschicht und das anschließende Mikrostrukturieren wurden entwickelt. Die Legierungsbildung zwischen Gallium und Gold sowie zwischen Gallium und Kupfer wurde im experimentell im Detail analysiert. Dabei konnte eine gute Korrelation zwischen der stofflichen Zusammensetzung und den mechanischen bzw. elektrischen Parametern der Zwischenschicht, auch und insbesondere hinsichtlich ihrer Temperaturabhängigkeit gefunden werden. Es stellte sich heraus, dass im Falle der Kombination Au/Ga Kirkendall Hohlräume in einer Menge entstehen, die zu erheblichen Problemen bezüglich mechanischer Festigkeit und Dichtheit der Fügeverbindung führen. Bei der Materialkombination Cu/Ga hingegen trat dieses Problem nur begrenzt auf; es war möglich hermetisch dichte Verbindungen herzustellen. Für die bei Kupfer nötige Vorbehandlung wurden mehrere Methoden erfolgreich getestet. Insgesamt konnte die Entwicklung von Fügetechnologien gezeigt werden, die metallische Zwischenschichten verwenden, elektrisch leitfähig sind, sehr gute Festigkeiten aufweisen und hermetisch dicht sind

Novel fine pitch interconnection methods using metallised polymer spheres

There is an ongoing demand for electronics devices with more functionality while reducing size and cost, for example smart phones and tablet personal computers. This requirement has led to significantly higher integrated circuit input/output densities and therefore the need for off-chip interconnection pitch reduction. Flip-chip processes utilising anisotropic conductive adhesives anisotropic conductive films (ACAs/ACFs) have been successfully applied in liquid crystal display (LCD) interconnection for more than two decades. However the conflict between the need for a high particle density, to ensure sufficient the conductivity, without increasing the probability of short circuits has remained an issue since the initial utilization of ACAs/ACFs for interconnection. But this issue has become even more severe with the challenge of ultra-fine pitch interconnection. This thesis advances a potential solution to this challenge where the conductive particles typically used in ACAs are selectively deposited onto the connections ensuring conductivity without bridging. The research presented in this thesis work has been undertaken to advance the fundamental understanding of the mechanical characteristics of micro-sized metal coated polymer particles (MCPs) and their application in fine or ultra-fine pitch interconnections. This included use of a new technique based on an in-situ nanomechanical system within SEM which was utilised to study MCP fracture and failure when undergoing deformation. Different loading conditions were applied to both uncoated polymer particles and MCPs, and the in-situ system enables their observation throughout compression. The results showed that both the polymer particles and MCP display viscoelastic characteristics with clear strain-rate hardening behaviour, and that the rate of compression therefore influences the initiation of cracks and their propagation direction. Selective particle deposition using electrophoretic deposition (EPD) and magnetic deposition (MD) of Ni/Au-MCPs have been evaluated and a fine or ultra-fine pitch deposition has been demonstrated, followed by a subsequent assembly process. The MCPs were successfully positively charged using metal cations and this charging mechanism was analysed. A new theory has been proposed to explain the assembly mechanism of EPD of Ni/Au coated particles using this metal cation based charging method. The magnetic deposition experiments showed that sufficient magnetostatic interaction force between the magnetized particles and pads enables a highly selective dense deposition of particles. Successful bonding to form conductive interconnections with pre-deposited particles have been demonstrated using a thermocompression flip-chip bonder, which illustrates the applicable capability of EPD of MCPs for fine or ultra-fine pitch interconnection

Nanoporous Gold: From Structure Evolution to Functional Properties in Catalysis and Electrochemistry

Nanoporous gold (NPG) is characterized by a bicontinuous network of nanometer-sized metallic struts and interconnected pores formed spontaneously by oxidative dissolution of the less noble element from gold alloys. The resulting material exhibits decent catalytic activity for low-temperature, aerobic total as well as partial oxidation reactions, the oxidative coupling of methanol to methyl formate being the prototypical example. This review not only provides a critical discussion of ways to tune the morphology and composition of this material and its implication for catalysis and electrocatalysis, but will also exemplarily review the current mechanistic understanding of the partial oxidation of methanol using information from quantum chemical studies, model studies on single-crystal surfaces, gas phase catalysis, aerobic liquid phase oxidation, and electrocatalysis. In this respect, a particular focus will be on mechanistic aspects not well understood, yet. Apart from the mechanistic aspects of catalysis, best practice examples with respect to material preparation and characterization will be discussed. These can improve the reproducibility of the materials property such as the catalytic activity and selectivity as well as the scope of reactions being identified as the main challenges for a broader application of NPG in target-oriented organic synthesis