Metal-Alloy Cu Surface Passivation Leads to High Quality Fine-Pitch Bump-Less Cu-Cu Bonding for 3D IC and Heterogeneous Integration Applications

In this paper, we report a low temperature, fine-pitch, bump-less, damascene compatible Cu-Cu thermocompression bonding, using an optimized ultra-thin passivation layer, Constantan, which is an alloy (Copper-Nickel) of 55% Cu and 45% Ni. Surface oxidation and its roughness are the major bottlenecks in achieving high quality, low temperature, and fine-pitch Cu-Cu bonding. In this endeavor, we have used Cu rich alloy (Constantan) for passivation of Cu surface prior to bonding. We have systematically optimized the constantan passivation layer thickness for high quality low temperature, low pressure, bump-less Cu-Cu bonding. Also, we have studied systematically the efficacy of Cu surface passivation with optimized ultra-thin constantan alloy passivation layer. After rigorous trial and optimization, we successfully identified 2 nm passivation layer thickness, at which very high quality Cu-Cu bonding could be accomplished at sub 200 °C with a nominal contact pressure of 0.4 MPa. Post-bonding, electrical and mechanical characterization were validated using four-probe IV measurement and bond strength measurement respectively. Furthermore, Cu-Cu bonding interface was analyzed using IR wafer bonder inspection tool. Very high bond strength of 163 MPa and defect free interface observed by WBI-IR clearly suggests, Cu-Cu finepitch bonding with optimized ultra-thin alloy of 2 nm thick constantan, is of very high quality and reliable. Moreover, this novel bonding approach with alloy based interconnect passivation technique is the prime contestant for future heterogeneous integration

Highly-sensitive Label-free Differential Pulse Voltammetric Immunosensor for Diagnosis of Infectious Diseases Based on Electrospun Copper Doped ZnO Nanofiber Biosensing Platform

Rapid detection of infectious diseases has generated significant interest in recent years. The time consuming and costly conventional diagnostics methods substantiate the need to develop a cost-effective rapid infectious disease detection platform to address the persistently threatening health issues in developing countries. The recent advancements in nanotechnology and biosensing have manifested the potential to deliver an effective point-of-care diagnostics platform. In this work, the synthesis and fabrication of an ultrasensitive Copper doped Zinc oxide nanofiber based biosensing platform is reported. Copper doped Zinc oxide nanofibers are synthesized by simple electrospinning technique with fiber diameter of 100-200 nm. The structural and morphological characteristics of the nanofibres are studied using X-ray diffraction and field emission scanning electron microscopy. The label free detection of HRP2 protein with the Copper doped Zinc Oxide nanofiber has been investigated by Differential pulse voltammetric technique. Mercaptopropionic acid treatment of Copper doped Zinc oxide nanofiber generates carboxylic acid groups, which facilitate the covalent conjugation of Anti-HRP2. To the best of our knowledge, the fabricated immunosensor displays better sensitivity than the best malaria sensor reported in the literature based on different nanomaterials and different detection mechanism. The proposed platform exhibits very low limit of detection of 10 attogram per ml for the targeted HRP2 protein in a wide detection test range (ag/ml -μg/ml). The novel biosensor platform demonstrates good stability and selectivity which can be implemented for point-of-care diagnosis of biomarkers related to other infectious diseases

Nonlithographic Fabrication of Plastic-Based Nanofibers Integrated Microfluidic Biochip for Sensitive Detection of Infectious Biomarker

We report fabrication of a fully integrated plastic based microfluidic biochip for biosensing application. The microfluidic channels were fabricated by tune transfer method and integrated with the prefunctionalized sensing platform. This approach to assembling microchannels into prefunctionalized sensing substrate facilitates controlled functionalization and prevents damages on the functionalized surface. The sensing platform comprised a three-electrode system, in which the sensing electrode was integrated with antibody immobilized carbon nanotubes-zinc oxide (C-ZnO) nanofibers. Electrospinning technique was used to synthesize C-ZnO nanofibers and the surface of the nanofibers was covalently conjugated with histidine rich protein II antibodies (AntiHRP II) toward detection of infectious malarial specific antigen, namely histidine-rich protein II (HRP II). The analytical performance of the fabricated biochip was evaluated by differential pulse voltammetry method. The device exhibited a high sensitivity of 1.19 mA/((g mL^–1)/cm²) over a wide detection range (10 fg/mL to 100 μg/mL) with a low detection limit of 7.5 fg/mL toward HRP II detection. This fully integrated biochip offers a promising cost-effective approach for detection of several other infectious disease biomarkers

Electrochemical Nanoengineered Sensors in Infectious Disease Diagnosis

This chapter reports a short review on electrochemical nanoengineered biosensors in infectious disease diagnosis. Early and timely diagnosis of infectious diseases has tremendous medical and social significance which advocates the development of new diagnostic tools. In this chapter, we discussed various electrochemical sensors for detection and diagnosis of tropical or subtropical fevers particularly dengue fever and malaria parasite. We also addressed the several important aspects of biosensors, namely, selectivity, sensitivity, and interference, and also the effect of engineering the nanomaterials (0D, 1D, 2D) on these aspects. In detail, we discussed the various techniques to immobilize the biomolecules on working electrode (glassy carbon, gold electrode, flexible substrates). Further, we discussed the several miniaturized sensing platforms with integrated microfluidic channels which can ensure for development of sensors for point-of-care applications

Biosensors Based on Nanomaterials: Transducers and Modified Surfaces for Diagnostics

The use of nanoparticles has opened a new era in the development of nanobiosensors capable of achieving analytical responses that compete with the most powerful instrumental techniques. Nanobiosensors are devices that allow analytical determinations through a specific action event between an analyte ofinterest and a bio-recognition molecule. These recognition molecules as enzymes,antibodies, nucleic acids, and aptamers are studied in detail in this chapter. The role of nanomaterials in biosensors is described in a separate section since they play a central role, allowing the understanding of their physicochemical properties such as quantum confinement, surface plasmon resonance, magnetic properties, and the effect of area increase. In addition, a brief review is provided about some basic concepts for the integration of the sensor components and their function in sensing systems found in the literature. Subsequently, a classification is proposed to summarize its fundamental characteristics, mechanism of operation, analytical characteristics, advantages, and disadvantages. Then, the main nanobiosensor types found in the literature are detailed, and specific explanations are given, e.g., those based on the determination of electrical, piezoelectric, colorimetric, fluorescent, and chemiluminescent properties. Likewise, the functioning of recently developed nanobiosensors is discussed, such as those based on local (SERS). Also, the applications of nanobiosensors in different fields of biomedicine and their fundamental importance to advance in the diagnosis of multiple pathologies as cancer are detailed. Finally, we discuss the state of the art and the future perspectives of scientific development.Fil: Romero, Marcelo Ricardo. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; ArgentinaFil: Picchio, Matías Luis. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin