MEMS Technologies Enabling the Future Wafer Test Systems

As the form factor of microelectronic systems and chips are continuing to shrink, the demand for increased connectivity and functionality shows an unabated rising trend. This is driving the evolution of technologies that requires 3D approaches for the integration of devices and system design. The 3D technology allows higher packing densities as well as shorter chip-to-chip interconnects. Micro-bump technology with through-silicon vias (TSVs) and advances in flip chip technology enable the development and manufacturing of devices at bump pitch of 14 μm or less. Silicon carrier or interposer enabling 3D chip stacking between the chip and the carrier used in packaging may also offer probing solutions by providing a bonding platform or intermediate board for a substrate or a component probe card assembly. Standard vertical probing technologies use microfabrication technologies for probes, templates and substrate-ceramic packages. Fine pitches, below 50 μm bump pitch, pose enormous challenges and microelectromechanical system (MEMS) processes are finding applications in producing springs, probes, carrier or substrate structures. In this chapter, we explore the application of MEMS-based technologies on manufacturing of advanced probe cards for probing dies with various new pad or bump structures

Experimental determination of optimal clamping torque for AB-PEM fuel cell

Polymer electrolyte Membrane (PEM) fuel cell is an electrochemical device producing electricity by the reaction of hydrogen and oxygen without combustion. PEM fuel cell stack is provided with an appropriate clamping torque to prevent leakage of reactant gases and to minimize the contact resistance between gas diffusion media (GDL) and bipolar plates. GDL porous structure and gas permeability is directly affected by the compaction pressure which, consequently, drastically change the fuel cell performance. Various efforts were made to determine the optimal compaction pressure and pressure distributions through simulations and experimentation. Lower compaction pressure results in increase of contact resistance and also chances of leakage. On the other hand, higher compaction pressure decreases the contact resistance but also narrows down the diffusion path for mass transfer from gas channels to the catalyst layers, consequently, lowering cell performance. The optimal cell performance is related to the gasket thickness and compression pressure on GDL. Every stack has a unique assembly pressure due to differences in fuel cell components material and stack design. Therefore, there is still need to determine the optimal torque value for getting the optimal cell performance. This study has been carried out in continuation of development of Air breathing PEM fuel cell for small Unmanned Aerial Vehicle (UAV) application. Compaction pressure at minimum contact resistance was determined and clamping torque value was calculated accordingly. Single cell performance tests were performed at five different clamping torque values i.e 0.5, 1.0, 1.5, 2.0 and 2.5 N m, for achieving optimal cell performance. Clamping pressure distribution tests were also performed at these torque values to verify uniform pressure distribution at optimal torque value. Experimental and theoretical results were compared for making inferences about optimal cell performance. A clamping torque value of 1.5 N m was determined experimentally to be the best for getting optimal performance as well as uniform pressure distribution for this specific fuel cell

Surface Modification of Reverse Osmosis Desalination Membranes with Zwitterionic Silane Compounds for Enhanced Organic Fouling Resistance

Three different zwitterionic functional trimethoxysilane compounds, 4-(diethyl(3-(trimethoxysilyl)propyl)ammonia)butane-1-sulfonate (EPBS), 4-(dimethyl(3-(trimethoxysilyl)propyl)ammonia)butane-1-sulfonate (MPBS), and 3-(dimethyl(3-(trimethoxysilyl)propyl)ammonia)propane-1-sulfonate (MPPS), were synthesized and used for the surface modification of commercial polyamide thin-film composite reverse osmosis membranes to enhance their salt rejection and antifouling performance. Commercial membrane surfaces were spray-coated using three different aqueous solution concentrations (1.0, 1.5, and 2.0%) of each zwitterionic silane compound. Surface characterization of coated membranes performed via X-ray photoelectron spectroscopy and water contact angle measurements confirmed the successful, permanent attachment of zwitterionic groups to membrane surfaces. Organic fouling studies accomplished through dead-end stirred cell filtration experiments using xanthan gum and bovine serum albumin revealed that all coated membranes had higher flux recovery rates upon cleaning with water and NaOH, demonstrating the easier cleanability provided by zwitterionic groups on the membrane surface. For example, in the case of xanthan gum fouling experiments, membranes coated with 2.0 wt % MPPS solution regained 100% of its initial flux after cleaning with deionized water, whereas the control membrane had 69% flux recovery

Manufacturing Process Development for Thin Film Filaments as a New Product

Thin films of rare-earth hexaborides are promising for wear and corrosion protective, decorative, and thermionic coatings. Among many hexaborides available, due to its unique properties lanthanum hexaboride (LaB6) is used as a bright and long life thermionic electron source mostly in electron microscopes. Unlike single-crystal LaB6 cathodes used today, LaB6 thin-film coated metal filaments can be advantageous due to their simple design, easy installation, cost-efficient manufacturing, and less energy consumption. In the study, LaB6 thin films were grown onto tantalum, molybdenum, and tungsten wire-substrates using magnetron sputtering. Tape-test was used on the film surface to determine the adhesion of the LaB6 films to the substrates. The morphology, structure, and stoichiometry of tape-tested films were investigated by stereo microscopy, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Stereo microscopy and SEM analysis showed that the films were grown by magnetron sputtering have dense, fine columnar structure without peeling or flaking. In the XPS analysis of LaB6/W film it was observed that the film was oxidized and there were no peaks of any element other than lanthanum, boron, and oxygen found. The analysis shows that the composition of the film was LaBx coated over the tungsten (W) substrate at the deposition conditions. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG

Smart Manufacturing of Electric Vehicles

The future of the manufacturing sector is evolving with the Industry 4.0, and its repercussions are felt in the factory, the business, product launch and also impacts customer aspects in the overall cycle. These technological innovations create opportunities for new disruptive entries to the market, for instance in automotive manufacturing. It is well known that the automotive industry is under the control of large OEMs since the very beginning. It is very difficult to compete as a newcomer because the production process of the Internal Combustion Engine (ICE) and the chassis require high technology, investment, and a well-defined supply chain that create a monopolistic environment for the sector. Therefore, we propose a microfactory concept as a novel manufacturing method that allows a quicker entry for new players in the automotive industry especially for electric vehicles (EVs). The microfactory described in this paper, presents an alternative solution to overcome the existing monopolies with the electric motor, a tubular chassis allows for lean manufacturing, and a novel supply chain model. Digital transformation shows itself in production systems by Industry 4.0 applications and more recently in the blockchain-based supply chain applications are being investigated. Further, a detailed cost analysis to compare conventional car manufacturing and microfactory concept EV manufacturing are presented. In addition, the blockchain technology is proposed to improve the supply chain of EV manufacturing. This study indicates that the microfactory provides flexible and customized production of urban electric vehicles minimizing both ecological footprint and total investment. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG