Experimental Techniques for Static and Dynamic Analysis of Thick Bonding Wires

Thick bonding wires are used in modern power modules as connectors between integrated circuits, carrying current from one circuit to another. They experience high values of current, which generates heat through Joule heating and can lead to various failure mechanisms. Typically used wire materials in industry are aluminum (Al), copper (Cu), and intermetallic compounds of Cu-Al. They are broadly used because of their strength, high thermal conductivity, and low resistivity. This study reports on the influence of thermal loading on the mechanical behaviour of bonding wires. Experimental techniques are developed and introduced in this thesis to analyze quasi-static and dynamic response of bonding wires 300 µm in diameter. First, an experimental technique is developed to measure the quasi-static displacement of bonding wires carrying DC currents. It is then deployed to measure the displacement, as well as peak temperature, of three types of bonding wires, Al, Cu and Aluminum coated Copper (CuCorAl) to study the response under DC current. Secondly, an experimental technique is established and deployed for modal analysis of bonding wires under thermal loading. Experimental results demonstrate a drop in the natural frequency of bonding wires with increased thermal loads. Moreover, a harmonic analysis technique using thermal excitation is developed and applied to analyze the mode shapes and frequency response of bonding wires. Furthermore, an analytical model and a finite element model are used to analyze static and dynamic responses of bonding wires. Numerical and experimental results are compared in this thesis

Dynamic Scanning Probe Lithography and Its Applications

This dissertation presents a novel, benchtop, low-cost, high-throughput direct surface patterning method dubbed dynamic-Scanning Probe Lithography (d-SPL). It employs a scriber mounted via a spring-damper mechanism to a nano-resolution 3D stage. As the scriber traverses the substrate surface, non-uniformity in the surface morphology leads to time-variation in the magnitude and direction of the contact force, which in turn generates scriber vibrations. The spring-damper mechanism dissipates those vibrations and stabilizes the contact force, thereby enabling long and uniform micro and nano patterns on a wide variety of substrates and preventing scriber tip failure. An analytical model was developed to investigate the dynamics of d-SPL and determine its safe operation conditions and limitations. It was used to investigate and explain, for the first time, a small micro-scale chatter phenomenon observed in the response of d-SPL. The model was validated through comparison to experiments. d-SPL was utilized for high velocity fabrication of micro and nanochannels at 1 mm/s. The channel dimensions are controlled by the scriber surface contact force. d-SPL also provided the basis for a novel rapid fabrication method that enhances the output power of triboelectric nanogenerators (TENGs) by simultaneously creating centimeter-long nano grooves (NGs) and nano triangular prisms (NTPs) on the surface of polymeric triboelectric materials. The output power of the nano structured TENGs was 12.2 mW compared to 2.2 mW for flat TENGs. A coupled electromechanical model was developed to describe the energy flow through the TENGs. Analytical and experimental results for the proposed TENGs show that they can harvest low-frequency and wide-band vibrations below 10 Hz. d-SPL can also fabricate long micro and nano wires through a continuous chip removal process. The wire dimensions can be controlled via the tip-substrate contact force while taking into account the substrate material. Continuous chip removal produced millimeter long, helical shaped gold nano wires out of a 600 nm thick gold layer on a dielectric substrate. Continuous flexible helical polymeric micro wires were obtained by chip removal from a Poly (methyl methacrylate) (PMMA) substrate. The wires were coated with 50nm Silver (Ag) layer to produce flexible conductive micro-helical wires. It was found that these wires can behave as freely standing cantilever beams. A low-cost and rapid fabrication of back-gated field effect transistors (BGFETs) was also developed based on d-SPL. A silver layer pre-coated on top of another SiO2 layer was patterned into interdigitated electrodes (IDEs) to form the source and drain of a FET with a channel length of 20 µm. A glycol-graphene mixture was then deposited to create the channel between the source and drain using a nanostage integrated microplotter and allowed to dry naturally. The Ion/Ioff ratio of the fabricated BGFET was calculated from the I-V curve as a 10^3

Tape'n roll inertial microfluidics

International Workshop on Piezoelectric Materials and Applications in Actuators (IWPMA) -- SEP 11-14, 2018 -- Kobe Chamber Commerce, Kobe, JAPANGULER, MUSTAFA TAHSIN/0000-0002-0478-3183WOS: 000496341800028Particle focusing and separation in microfluidic devices are critical for biological and medical applications. Inertial microfluidics is used for high throughput bio-particle focusing and separation. Most of the inertial microfluidic systems use planar structures for squeezing the particles in streams. Particle manipulation in 3D structures is often overlooked due to the complexity of the fabrication. In this study, we introduce some novel microchannel designs for inertial microfluidics by using a simple fabrication method that allows construction of both 2D and 3D structures. First, inertial migration of particles in 2D layouts including straight, spiral, and square spiral channels is investigated. Afterward, by applying a "tape'n roll" method, helical and double oriented spiral channels are configured and unexplored inertial migration behaviours are observed. Thanks to the simplicity of the fabrication and the unique characteristics of the new designs, high performance microfluidic inertial migration results can be obtained without any need for complicated microfabrication steps. The design optimization cycle can also be shortened using a computational approach we introduce in this study. (C) 2019 Elsevier B.V. All rights reserved.Japan Soc Precis Engn, Next Generat Sensors & Actuators Com

Long-Term Stability of Ferroelectret Energy Harvesters

DAS, MEMIK TAYLAN/0000-0002-9872-8977; Kayaharman, Muhammed/0000-0002-1567-4142; Abdel-Rahman, Eihab/0000-0002-3709-7593WOS: 000515499300042PubMed: 31861779Cellular polypropylene (PP) has been recently used in energy harvesting applications. In this work, we investigate its viability and long-term stability under various operating conditions. Specifically, the effect of constant stress and stress cycling on output power and long-term stability of ferroelectret energy harvesters is analyzed. Our findings show that after 112 days constant stress significantly increases the piezoelectric charge constant d(33) and output power from 0.51 mu W for a stress-free harvester to 2.71 mu W. It also increases the harvester center frequency from 450 to 700 Hz and decreases its optimal resistance from 7 to 5.5 M Omega

Built-In Packaging for Single Terminal Devices

An alternative packaging method, termed built-in packaging, is proposed for single terminal devices, and demonstrated with an actuator application. Built-in packaging removes the requirements of wire bonding, chip carrier, PCB, probe station, interconnection elements, and even wires to drive single terminal devices. Reducing these needs simplifies operation and eliminates possible noise sources. A micro resonator device is fabricated and built-in packaged for demonstration with electrostatic actuation and optical measurement. Identical actuation performances are achieved with the most conventional packaging method, wire bonding. The proposed method offers a compact and cheap packaging for industrial and academic applications

Resonant Adaptive MEMS Mirror

A novel MEMS continuous deformable mirror (DM) is presented. The mirror can be integrated into optical systems to compensate for monochromatic and chromatic aberrations. It is comprised of a 1.6 mm circular plate supported by eight evenly spaced flexural springs. Unlike traditional bias actuated DMs, it uses resonant electrostatic actuation (REA) to realize low- and high-order Zernike modes with a single drive signal. Instead of the hundreds or thousands of electrodes deployed by traditional DMs, the proposed DM employs only 49 electrodes and eliminates the need for spatial control algorithms and associated hardware, thereby providing a compact low-cost alternative. It also exploits dynamic amplification to reduce power requirements and increase the stroke by driving the DM at resonance. The DM was fabricated using a commercial silicon-on-insulator (SOI) MEMS process. Experimental modal analysis was carried out using laser Doppler vibrometry (LDV) to identify mode shapes of the DM and their natural frequencies. We are able to observe all of the lowest eight Zernike modes

Resonant Adaptive MEMS Mirror

A novel MEMS continuous deformable mirror (DM) is presented. The mirror can be integrated into optical systems to compensate for monochromatic and chromatic aberrations. It is comprised of a 1.6 mm circular plate supported by eight evenly spaced flexural springs. Unlike traditional bias actuated DMs, it uses resonant electrostatic actuation (REA) to realize low- and high-order Zernike modes with a single drive signal. Instead of the hundreds or thousands of electrodes deployed by traditional DMs, the proposed DM employs only 49 electrodes and eliminates the need for spatial control algorithms and associated hardware, thereby providing a compact low-cost alternative. It also exploits dynamic amplification to reduce power requirements and increase the stroke by driving the DM at resonance. The DM was fabricated using a commercial silicon-on-insulator (SOI) MEMS process. Experimental modal analysis was carried out using laser Doppler vibrometry (LDV) to identify mode shapes of the DM and their natural frequencies. We are able to observe all of the lowest eight Zernike modes

Achieving Ultrahigh Piezoelectricity in Organic–Inorganic Vacancy-Ordered Halide Double Perovskites for Mechanical Energy Harvesting

International audiencePiezoelectric charge coefficient (d33) and piezoelectric voltage coefficient (g33) are the two most critical parameters that define output performance of piezoelectric nanogenerators (PNGs). Herein, we propose a vacancy-ordered double perovskite of TMCM2SnCl6 (where TMCM is trimethylchloromethylammonium) with a large d33 of 137 pC/N and g33 of 980 × 10–3 V·m/N. The piezoelectric coefficients are considered from the halogen-bonding-mediated synergistic movements of atomic displacement in inorganic [SnCl6]2– octahedrons, as well as the molecular rotation of organic TMCM+, which is revealed by a combined density functional theory (DFT) and experimental study. The TMCM2SnCl6 possesses a high saturated polarization (Ps) of 8.7 μC/cm2, a high Curie temperature (Tc) of 365 K, and a low coercive field (Ec) of 0.6 kV/cm. The output voltage (Voc) and current (Isc) of the PNGs are 81 V and 2 μA at an applied mechanical excitation of (4.9 N, 40 Hz). We hope this work will provide guidance in energy harvesting by innovatively designing highly piezoelectric perovskites for the PNGs

Nano Groove and Prism-Structured Triboelectric Nanogenerators

Enhancing the output power of triboelectric nanogenerators (TENGs) requires the creation of micro or nano-features on polymeric triboelectric surfaces to increase the TENGs’ effective contact area and, therefore, output power. We deploy a novel bench-top fabrication method called dynamic Scanning Probe Lithography (d-SPL) to fabricate massive arrays of uniform 1 cm long and 2.5 µm wide nano-features comprising a 600 nm deep groove (NG) and a 600 nm high triangular prism (NTP). The method creates both features simultaneously in the polymeric surface, thereby doubling the structured surface area. Six thousand pairs of NGs and NTPs were patterned on a 6×5 cm2 PMMA substrate. It was then used as a mold to structure the surface of a 200 µm thick Polydimethylsiloxane (PDMS) layer. We show that the output power of the nano-structured TENG is significantly more than that of a TENG using flat PDMS films, at 12.2 mW compared to 2.2 mW, under the same operating conditions (a base acceleration amplitude of 0.8 g)