Ever growing demands for portability and functionality have always governed the electronic technology innovations. IC downscaling with Moore s law at IC level and system miniaturization with System-On-Package (SOP) paradigm at system level, have resulted and will continue to result in ultraminiaturized systems with unprecedented functionality at reduced cost. However, system miniaturization poses several electrical and thermal challenges that demand innovative solutions including advanced materials, bonding and assembly techniques. Heterogeneous material and device integration for thermal structures and IC assembly are limited by the bonding technology and the electrical and thermal impedance of the bonding interfaces. Solder - based bonding technology that is prevalent today is a major limitation to future systems. The trend towards miniaturized systems is expected to drive downscaling of IC I/O pad pitches from 40µm to 1- 5µm in future. Solder technology imposes several pitch, processability and cost restrictions at such fine pitches. Furthermore, according to International Technology Roadmap for Semiconductors (ITRS-2006), the supply current in high performance microprocessors is expected to increase to 220 A by 2012. At such supply current, the current density will exceed the maximum allowable current density of solders. The intrinsic delay and electromigration in solders are other daunting issues that become critical at nanometer sized technology nodes. In addition, formation of intermetallics is also a bottleneck that poses significant mechanical issues. Similarly, thermal power dissipation is growing to unprecedented high with a projected power of 198 W by 2008 (ITRS 2006). Present thermal interfaces are not adequate for such high heat dissipation. Recently, copper based thin film bonding has become a promising approach to address the abovementioned challenges. However, copper-copper direct bonding without using solders has not been studied thoroughly. Typically, bonding is carried out at 400oC for 30 min followed by annealing for 30 min. High thermal budget in such process makes it less attractive for integrated systems because of the associated process incompatibilities. Hence, there is a need to develop a novel low temperature copper to copper bonding process. In the present study, nanomaterials - based copper-to-copper bonding is explored and developed as an alternative to solder-based bonding. To demonstrate fine pitch bonding, the patterning of these nanoparticles is crucial. Therefore, two novel self-patterning techniques based on: 1.) Selective wetting and 2.) Selective nanoparticle deposition, are developed to address this challenge. Nanoparticle active layer facilitates diffusion and, thus, a reliable bond can be achieved using less thermal budget. Quantitative characterization of the bonding revealed good metallurgical bonding with very high bond strength. This has been confirmed by several morphological and structural characterizations. A 30-micron pitch IC assembly test vehicle is used to demonstrate fine pitch patternability and bonding. In conclusion, novel nanoparticle synthesis and patterning techniques were developed and demonstrated for low-impedance and low-cost electrical and thermal interfaces.

Ever growing demands for portability and functionality have always governed the electronic technology innovations. IC downscaling with Moore s law and system miniaturization with System-On-Package (SOP) paradigm has resulted and will continue to result in ultraminiaturized systems with unprecedented functionality at reduced cost. The trend towards 3D silicon system integration is expected to downscale IC I/O pad pitches from 40µm to 1- 5 µm in future. Device- to- system board interconnections are typically accomplished today with either wire bonding or solders. Both of these are incremental and run into either electrical or mechanical barriers as they are extended to higher density of interconnections. Alternate interconnection approaches such as compliant interconnects typically require lengthy connections and are therefore limited in terms of electrical properties, although expected to meet the mechanical requirements. As supply currents will increase upto 220 A by 2012, the current density will exceed the maximum allowable current density of solders. The intrinsic delay and electromigration in solders are other daunting issues that become critical at nanometer size technology nodes. In addition, formation of intermetallics is also a bottleneck that poses significant mechanical issues. Recently, many research groups have investigated various techniques for copper-copper direct bonding. Typically, bonding is carried out at 400oC for 30 min followed by annealing for 30 min. High thermal budget in such process makes it less attractive for integrated systems because of the associated process incompatibilities. In the present study, copper-copper bonding at ultra fine-pitch using advanced nano-conductive and non-conductive adhesives is evaluated. The proposed copper-copper based interconnects using advanced conductive and non-conductive adhesives will be a new fundamental and comprehensive paradigm to solve all the four barriers: 1) I/O pitch 2) Electrical performance 3) Reliability and 4) Cost. This thesis investigates the mechanical integrity and reliability of copper-copper bonding using advanced adhesives through test vehicle fabrication and reliability testing. Test vehicles were fabricated using low cost electro-deposition techniques and assembled onto glass carrier. Experimental results show that proposed copper-copper bonding using advanced adhesives could potentially meet all the system performance requirements for the emerging micro/nano-systems.

No description available.

Small form-factor packages with high integration density are driving the innovations in chip-to-package interconnections. Metallurgical interconnections have evolved from the conventional eutectic and lead-free solders to fine pitch copper pillars with lead-free solder cap. However, scaling down the bump pitch below 50-80µm and increasing the interconnect density with this approach creates a challenge in terms of accurate solder mask lithography and joint reliability with low stand-off heights. Going beyond the state of the art flip-chip interconnection technology to achieve ultra-fine bump pitch and high reliability requires a fundamentally- different approach towards highly functional and integrated systems. This research demonstrates a low-profile copper-to-copper interconnect material and process approach with less than 20µm total height using adhesive bonding at lower temperature than other state-of-the-art methods. The research focuses on: (1) exploring a novel solution for ultra-fine pitch (< 30µm) interconnections, (2) advanced materials and assembly process for copper-to-copper interconnections, and (3) design, fabrication and characterization of test vehicles for reliability and failure analysis of the interconnection. This research represents the first demonstration of ultra-fine pitch Cu-to-Cu interconnection below 200°C using non-conductive film (NCF) as an adhesive to achieve bonding between silicon die and organic substrate. The fabrication process optimization and characterization of copper bumps, NCF and build-up substrate was performed as a part of the study. The test vehicles were studied for mechanical reliability performance under unbiased highly accelerated stress test (U-HAST), high temperature storage (HTS) and thermal shock test (TST). This robust interconnect scheme was also shown to perform well with different die sizes, die thicknesses and with embedded dies. A simple and reliable, low-cost and low-temperature direct Cu-Cu bonding was demonstrated offering a potential solution for future flip chip packages as well as with chip-last embedded active devices in organic substrates.

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Systems Science and Industrial Engineering, 2008. / Includes bibliographical references.

This Thesis describes the synthesis and characterisation of new alkaline earth- and rare earth-transition metal complexes. Experimental and computational studies were performed to investigate the structure and bonding in these complexes. Their reactivity was also studied. Chapter 1 introduces metal-metal bonded complexes and current alkaline earth- and rare earth-transition metal bonded complexes. Chapter 2 describes experimental and computational studies of new alkaline earth- and lanthanide-Fe complexes possessing the [CpFe(CO)2]- anion. Chapter 3 presents experimental studies of the reduction of Fe3(CO)12 with Ca. Chapter 4 describes experimental and computational studies of new alkaline earth- and lanthanide-Co complexes containing the [Co(CO)3(PR3)]- anion. Chapter 5 presents full experimental procedures and characterising data for the new complexes reported. Appendix describes the attempted synthesis of [Ca{CpRu(CO)2}2(THF)x]y and study by DFT of [CaRp2(THF)3]2 CD Appendix contains .cif files for all new crystallographically characterised complexes described.

Le secteur aéronautique connaît un important essor depuis les années 1960, avec pour conséquence l’augmentation majeure des températures de fonctionnement des turbines. L’utilisation de capteurs, au plus proche de la chambre de combustion, est nécessaire pour maîtriser les performances des turboréacteurs. Cela justifie le besoin industriel de développer des assemblages céramique-métal résistants à un environnement sévère (>1100°C sous air, vibrations, etc.)L’alumine est sélectionnée en raison de son caractère isolant à haute température. La principale difficulté réside dans le choix du substrat métallique, qui doit être à la fois : réfractaire, résistant à l’oxydation, pour un coût abordable. Le potentiel d’un carbure ternaire (de type phase MAX) est évalué en tant que substrat métallique. La composition des brasures est ajustée pour chaque système afin de garantir : une tenue en température, une excellente ductilité et une compatibilité métallurgique vis-à-vis du substrat métallique.Des brasures ternaires Au-Pd-Pt sont formulées et élaborées. Les contours de solidus et de liquidus de ce ternaire sont déterminés expérimentalement. Les mécanismes de diffusion, de dissolution ou encore de pénétration inter-granulaire, à l’interface métal/brasure, sont décrits afin d’apporter des améliorations aux systèmes développés. Au cours du brasage, la diffusion de l’aluminium des substrats alumino-formeurs vers la brasure est prédominante, malgré la mise en place d’une barrière de diffusion. Le recours à des substrats métalliques nobles s’avère incontournable.Les paramètres géométriques et chimiques de l’assemblage sont établis pour chaque nouveau système étudié sur la base des processus physico-chimiques survenant au cours du brasage et du vieillissement sous air. Les meilleurs assemblages développés présentent une excellente herméticité après brasage. Les essais de vieillissement en cyclage thermique, dans des conditions sévères, sollicitent fortement la liaison céramique-brasure jusqu’à la rupture interfaciale. Deux voies d’améliorations sont proposées pour assurer la durabilité de la liaison céramique-brasure au cours du cyclage thermique. / Aerospace technology developments are blooming. Since the 1960’s the Turbine Entry Temperature for aero-engines gas turbines keeps rising to improve their efficiency. Sensors working close to the combustion chamber are required in order to master the turbine performances. This results in an industrial urge to develop ceramic-to-metal assemblies able to endure severe engine environment (>1100°C under air, vibrations, etc.)The choice of an alumina as the ceramic part ensures a good insulation at high temperature. The main issue remains the metallic material which must be refractory, resistant to oxidation and affordable. The application of a ternary carbide (phase MAX) is tested. The braze alloy composition is adjusted to each system so as to provide a good ductility, thermal stability and a metallurgical matching as regards dissolution and brittle compounds formation.Braze alloys based on the Au-Pd-Pt system are investigated. The aforesaid liquidus and solidus surfaces are defined from experimental measures. Diffusion, dissolution and inter-granular penetration at the metal/braze alloy interface are described to suggest improvements. Aluminum diffusion from alumina-forming materials towards the braze alloy is the dominant phenomenon during brazing, despite the use of a diffusion barrier. The use of noble materials for the metallic substrate is mandatory.Geometrical and chemical assembly parameters are defined for selected brazed system based on the physicochemical interactions occurring during brazing and aging under air. The best brazed assemblies present an excellent hermeticity after brazing. Thermal cycling aging in severe conditions is detrimental to ceramic-braze alloy bonding, leading to interfacial cracks. Two promising strategies are suggested to ensure a reliable ceramic-to-braze alloy bonding during thermal cycling.