bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultraviolet LED Multi-Chip Module Based on Ceramic Substrate
Authors: Burkhardt T. , Hornaff M. , Acker A. , Peschel T. , Beckert E. , Suphan K.-H. , Mensel K. , Jirak S. , Eberhardt R. , Tünnermann A. 
Published: October 2015

A high power ultraviolet (UV) light emitting diode (LED) multi-chip module package based on aluminum nitride (AlN) and alumina (Al2O3) is presented. The AlN substrate with a high thermal conductivity of up to 180 W/(m· K) and LED chips based on a copper alloy provide superb thermal management and heat extraction. Efficient cooling is an important prerequisite for the increase of extractable optical power and decrease of thermally induced wavelength shift. A design of a stackable module featuring arrays of 7×2 indium-gallium-aluminum- nitride UV LED chips at 395 nm is developed. This configuration of sub-modules allows for the scalable assembly of line sources with different lengths. Applications using UV LEDs cover market segments such as curing of adhesives, inks and coatings, sterilization of medical equipment and treatment of potable water, as well as various uses in chemical detection, biochemical analytics and spectroscopy.
Thermal and thermo-mechanical modelling of the sub-mount is conducted using finite elements analysis. Die attach using eutectic gold-tin solder, lower melting tin-lead solder and silver-filled adhesive are compared with respect to optical output power and wavelength drift. Mechanical strength and structure of the resulting joints are investigated using shear force measurements, cross-sectioning and micro-tomography. An optical output power of 7.7 W is achieved using a cluster of 14 LED chips at 1050 mA resulting in a peak irradiance of 30.8 W/cm2 at the LED surface with respect to the footprint and pitch of the attached chips.
Optimized cavities for microwave applications using the new low loss LTCC material Du Pont 9k7
Authors: Schulz Alexander , Welker Tilo , Gutzeit Nam , Stoepel Dirk , Wollenschlaeger Frank , Mueller Jens 
Published: October 2015

This paper presents two different novel methods to manufacture optimized cavity structures, which are suitable for multilayer System-in-Package (SiP) and Multi-Chip-Module (MCM) applications, in the new low temperature cofired ceramic (LTCC) material Du Pont 9k7. In contrast to standard manufacturing, the improved DP 9k7 cavities show almost perfectly orthogonal cross sections and straight edges, achieved by applying special cavity inlays or cast silicone. Ball-wedge bond wires and wedge-wedge ribbons are implemented directly to the cavity rim successfully.
Therefore, these cavities are suitable for very short bond wires in complex RF systems and the introduced techniques are very promising for future applications using DP 9k7.
Fab in a Package: LTCC Microfluidic Devices for Micro and Nanoparticle Fabrication
Authors: Gongora-Rubio Mário Ricardo , Freitas Kellen Heloizy Garcia , de Novais Schianti Juliana , de Oliveira Adriano Marim , Cerize Natália Neto Pereira , Zanin Maria Helena Ambrosio 
Published: October 2015

The chemical industry is moving toward miniaturization with the help of microreaction technology and automated control systems. Besides the evident advantages of Microtechnology like improved portability, reduced energy use, safety and flexibility, the main advantage associated with the miniaturization of chemical processes is the increased microreactor control due to predictable thermal and mass transportation properties. We understand that LTCC Microsystem technology have a relevant role in this area.
LTCC Microfluidic devices have been applied to carry out several chemical processes operations, including mixing, separation, chemical reactions, heterogeneous catalysis, heat exchange and so on. More recently, LTCC microfluidic systems have also been used to produce micro- and nanoparticles with excellent control of size distribution, morphology and constitution.
The present work give an account of some LTCC Microfluidic devices aimed for Micro and Nanoparticle fabrication. At this time we report devices for: Emulsion generation for obtaining alginate microparticles by ionic gelation; Electrospinning applications, Microreactors for silver nanoparticle production and 3D Flow focusing devices for pharmaceutical active nanocrystallization.
Manufacturing and Characterization of a Deformable LTCC Membrane with Integrated Temperature Sensors, Strain Gauges and Heating Structures
Authors: Gutzeit N. , Müller J. , Bruchmann C. , Gebhardt S. 
Published: October 2015

The wavefront of high energy lasers can be corrected by using a deformable mirror. This mirror is a complex multimaterial device based on a LTCC membrane (DP 951) with a galvanically deposited and polished copper surface. In the membrane temperature sensors, strain gauges and heaters are integrated to measure deformation and temperature and to influence the latter. The laser wavefront is corrected by deforming the membrane with screen printed, segmented PZT thick film actuators.
In this paper the challenging manufacturing process of the mirror is described. During processing the LTCC membrane with integrated sensors must endure the postfired sintering of PZT at temperatures of up to 900°C without any degradation of the sensors' characteristics.
In order to optimize the sensors, various combinations of resistor and conductor pastes and different geometries are characterized. The usability and the performance of the sensor elements after temperature treatment are investigated by measuring the resistance and its resistance temperature characteristic.
For the detection of the membrane deformation, an array of miniaturized strain gauges is used. To achieve a controlled temperature distribution across the membrane different buried heater concepts are manufactured and characterized.
In order to improve the mechanical stability of the membrane, a rim of fired LTCC (width: 6 mm, diameter: 52 mm, thickness: 600 μm) is bonded to the multilayer membrane using a sealing glass.
Low-temperature sintered NTC ceramics for thick film temperature sensors
Authors: Reimann T. , Töpfer J. , Barth S. 
Published: October 2015

Printed thick film NTC thermistors and multilayer devices are frequently used for temperature control in hybrid circuits. NiMn2O4 and substituted spinels are the most established materials for this application. For low-temperature sintering at 900 °C the shrinkage behavior of the thermistor material has to be adjusted by the addition of proper sinter additives.
We investigated the chemical stability of NiMn2O4 and substituted spinels in air between 25 °C and 1200 °C. The compound NiMn2O4 is stable from 700 °C to 970 °C only and interacts with the sinter additives. Stable cubic spinels were found in the system ZnxNi0,5Co0,5Mn2-zO4. Addition of liquid phase sintering additives to the spinel powders results in complete densification at 900 °C. No chemical interaction between spinel and additive was observed. The effect of Cu-substitution into the spinel was also investigated.
Functional NTC pastes were printed on alumina substrates and post-fired at 900 °C. The NTC thermistor films have a sheet resistivity of about 300 kOhm/sq and B = 3300 K. The firing behavior, microstructure formation and electric properties of NTC thick films will be reported.
Transmit/Receive (T/R) Modules – Key Elements for Phased Array Antennas
Authors: Oppermann Martin , Schroth Joerg , Thurow Felix 
Published: October 2015

Modern Active Electronically Steered Antennas (AESA) are operating in different platforms and systems. Inside EADS/CASSIDIAN the focus on X-Band antennas today is in airborne and fighter nose radars, in satellite based SAR antennas (Synthetic Aperture Radar) for earth observation and ground surveillance and security radars.
Active antennas are assembled with hundreds or even thousands of T/R modules. This paper will describe an example of a so called standardized module solution based on LTCC package technology. State-of-the-art modules are assembled with active components like MMICs realized in GaAs technology, e.g. Low Noise Amplifier (LNA) and High Power Amplifier (HPA), Silicon based devices and passives. Assembly technologies are optimized for high yield series production inside CASSIDIAN MicroWave Factory. New semiconductor technologies, like GaN (Gallium Nitride) are enablers for a new T/R module generation. GaN/SiC based MMICs with higher power density compared with GaAs based devices are technological challenges for innovative thermal management solutions and assembly alternatives. GaN power devices are soldered on modern heatsink materials with high thermal conductivity and matched CTE (between MMIC and heatsink).
Results of thermal simulations comparing different heatsink materials in combination with soldering techniques will be discussed and an optimized solution will be shown. Another type of T/R Module technology based on RF-PCB and packaged MMICs will be discussed. Future applications of ground-based security radars, active antenna products with a one-dimensional array and needs for cost-effective solutions seem to be SMD-based products. Different packages, e.g. QFN (Quad Flat Pack no Lead) and ceramic based (HTCC), mainly for power devices will be shown and compared.
Characterization of Low Temperature Sintered Ferrite Laminates for High Frequency Point-of-Load Converters
Authors: Zhang Wenli , Mu Mingkai , Hou Dongbin , Su Yipeng , Li Qiang , Lee Fred C. 
Published: October 2015

The high power density Point-of-Load (POL) converter with high operating frequency has gained increasing interest in the growing market for portable communications and handheld electronics. Low profile magnetic components and associated integration techniques are desired for design and fabrication of highly integrated POL converters. Low fired ferrite tapes for multilayer chip inductors and high frequency applications have been developed and used in hybrid integration of power modules. The inductor made of multilayer ferrites can be fabricated as the magnetic substrate in an integrated POL converter with active components on top. The developed 3-D integration approach is applied to reduce footprint and increase power density for the high frequency POL converter.
The current work reports the characterization of magnetic properties, microstructures, and chemical compositions of commercially available low-fire Ni-Cu-Zn ferrite materials (ESL 40010, 40011, and 40012) and their mixed laminates. Permeability and core loss density are measured on toroidal shaped samples sintered at 885 °C for 3.5 hrs. Because high DC current is always applied to bias the core for the inductors used in high frequency POL converters, the influence of superimposed DC bias on the magnetic properties of ferrite laminates has also been evaluated. The microstructures and chemical compositions of low temperature sintered ferrite laminates are observed and analyzed in order to explain the difference of magnetic properties among samples. The mixed laminate with alternating layers of ESL 40010 and ESL 40012 in 1:1 ratio presents the highest permeability and the lowest core loss density among all examined samples when DC bias is above 1000 A/m. Finally, a 12 V to 1.2 V, 15 A, high frequency (1.5–5 MHz) integrated POL converter with laminated ferrite inductor has been fabricated and demonstrated working at high efficiency with power density as high as 1000 W/in3.
In Situ Characterization of the Sintering Behavior of LTCC Laminates with Embedded Cavities by High Temperature Laser Profilometry
Authors: Heunisch Andreas , Marzok Ulrich , Münchow Marco , Müller Ralf , Rabe Torsten 
Published: October 2015

Three-dimensionally structured LTCC multilayer with channels and inner cavities are required for numerous applications like microreactors, microfluidic systems or sensors. For the performance of such devices, the dimensional accuracy of the embedded structures is crucial. In the green state, the desired structures can be precisely implemented in the LTCC tapes by laser cutting, punching or milling. Unfortunately, during lamination and sintering, shape integrity of cavities and channels is notably affected by warpage and deformation.
To investigate the sintering behavior of structured LTCC laminates, a newly developed High Temperature Laser Profilometer (HTLP) can be used. The HTLP allows 3D in-situ shape detection of flat ceramic samples and tapes all along the sintering process. It is applicable for temperatures up to 1000 °C and sample sizes up to 200 mm × 200 mm × 10 mm. During a measurement, the rotating sample is scanned spirally by a linearly moving laser distance sensor through a slot in the furnace top wall. Distance and position values deliver a 3D surface image of the sample. Current lateral dimensions, which are determined by sintering shrinkage, can be measured continuously. Local deformation and warpage can be visualized time- and temperature-resolved.
This new method was used, to analyze the sintering behavior of LTCC multilayer laminates containing large size cavities. These were fabricated out of punched green sheets by low pressure lamination without inserts. Samples with cavities of varying cross sections, as well as cavities with and without connection to the surface were observed.
LTCC Piezoelectric Transducer for Energy Harvesting
Authors: Dabrowski Arkadiusz P. , Owczarzak Slawomir , Roguszczak Henryk , Golonka Leszek J. 
Published: October 2015

In this paper, design, technology and properties of multi cantilever transducer for energy harvesting application were described. The piezoelectric transducer was made in LTCC (Low Temperature Cofired Ceramics) technology using PZT (Lead Zirconate-Titanate) based tape. In such devices the highest power can be reached at resonance frequencies of the cantilevers. Eight bimorph transducers with lengths corresponding to 33, 50, 58, 66, 75, 82, 91 and 100 Hz resonant frequency, were designed. The transducers were polarized in serial or parallel configuration. To avoid voltage reduction in the system of a few piezoelectric bimorphs, rectifiers were applied for each cantilever.
Transducers had optimum resistance in ranges of 60–140 kΩ and 300–600 kΩ for bimorphs poled in parallel and serial configuration, respectively. The mean output power under sinusoidal excitation with 20 μm vibration amplitude calculated from all maxima at resonant frequencies for optimum load, were equal to 10.3 μW and 12.4μW for parallel and serial configurations with rectifier. Without rectifier the values were equal to 18.2 μW for both the transducers. In case of mean output power, the difference between both the transducers was not really significant, however at higher frequency the maximum power was higher for serial configuration. Besides, the output voltage obtained in serial bimorph was higher than in parallel one. The mean power density for all the resonant peaks measured at 0.41 g was equal to 210 μW/cm3/g and 360 μW/cm3/g with and without rectifier, respectively.
The influence of glassy carbon on tribological properties in metal – ceramic composites with skeleton reinforcement
Authors: Myalski Jerzy , Hekner Bartosz , Posmyk Andrzej 
Published: October 2015

This paper presents a results of mechanical and tribological properties of aluminum based composites with skeleton reinforcement. The aluminum alloy based composites were produced using pressure infiltration process. As a reinforcement ceramic foam with opened cells was applied. This reinforcement structure give an opportunity to limit the most common defects (like agglomeration, inhomogeneity, ect.) occurring in composite materials obtained by casting. In presented research three different types of porous foam were analysed. There were alumina foam covered by thin glassy carbon layer (Al2O3 – GC) and two types of glassy carbon foams (GC). Due to application of porous ceramic foam, an increasing of composite mechanical properties are expected. An additional glassy carbon layer with thickness up to 5 μm was applied for increasing a thermal conductivity and rapid heat dissipation from the material. Moreover, the skeleton structure of glassy carbon, and its wear mechanism, should decrease a friction coefficient value. Two manufactured types of composites: Al2O3 – GC foam and own produced glassy carbon foam were compared with material reinforced by spatial carbon structure obtained from commercial RVC (produced by Reynolds) foam.
The results showed that the application of porous ceramic and ceramic – carbon reinforcement skeletons led to increasing of mechanical properties of composite. The conducted research using pin–on–disc method, with 2,5 MPa of load and 1,0 m/s of speed revealed that glassy carbon have significant influence on decreasing friction coefficient and wear rate. An analysis of material external layer in areas after coupling with pin (wear track) indicated a fragmentation of glassy carbon foam. The wear products are not remove from friction surfaces, but these products create thin carbon film with lubricant properties. The conducted research showed both, a possibility to produce composites with skeleton structure of reinforcement and a possibility of correction of material tribological properties using glassy carbon.
Thermal Stress Reliability Study on Substrates for High Temperature, Silicon Carbide Power Electronic Modules
Authors: Shaw R. , Doyle P. , Hornberger J. , Lostetter A. , McPherson B. , Procell H. , Schupbach R. 
Published: October 2015

The goal of this study is to investigate packaging techniques for extreme environment (i.e., −50 °C to 250 °C) power electronics. Areas of interest include substrate materials and baseplate/heat spreader materials. Multiple substrate technologies are evaluated, including direct bond copper (DBC), direct bond aluminum (DBA), and active metal braze (AMB) substrates. When possible, varying thicknesses of ceramic and metal layers are included to determine if that parameter affects reliability. Within each material and thickness sample lot, different layout geometries and overall sizes are tested, again to determine if that specific parameter has an impact on reliability. In a power electronics application, these substrates are required to be attached to a baseplate/heat spreader for mechanical support and to improve thermal performance. Therefore, a smaller sample size of substrate materials was also tested for reliability when soldered to a metal matrix composite (MMC) baseplate. To evaluate the reliability of said materials, several inspection methods are utilized, comprising of scanning acoustic microscopy (SAM), optical microscopy, florescent penetrant inspection, cross section analysis, and optical profilometery.
This paper will present the results of thermal stress studies on each of the materials under varying conditions. The conditions include: thermal dwell conditions of 250 °C in excess of 1000 hours and thermal cycling from −50 °C to 250 °C in excess of 1000 cycles. Current results will be presented and discussed.
SLID Bonding for Energy Dense Applications – Thermo-Mechanics
Authors: Larsson Andreas , Tollefsen Torleif André 
Published: October 2015

Solid-Liquid Inter-Diffusion (SLID) bonding is traditionally a technology used for high performance and high reliable die attach/interconnect applications. The generic properties of SLID allows the bonding to occur at a relatively low process temperature. However, when the bond is completed, the final joint has a melting point well above the process temperature. This makes it well suited as for high performance electronic assemblies. The typical bonding temperature of Cu-Sn SLID and Au-Sn SLID are 250–300 °C and 320–350 °C respectively. These temperatures compare to that of other high temperature (HT) electronic adhesives e.g. Staystik® 101G. The thermal performance of the SLID bond is superior to other electronic interface materials. This is due to the thin joint (∼ 10 μm) and the high thermal conductivity (∼ 60 W/m·K for Au-Sn). Thus, the thermal resistance of a SLID joint, about 2×10−3 cm2·K/W, is significantly lower than most other thermo-mechanical joints suitable for use in electronic assemblies. SLID joints have also proven to be mechanically robust for harsh environment applications.
In this study the thermo-mechanical properties of large Cu-Sn SLID bond are investigated. Simulations are performed to explore the stationary thermo-mechanical performance of the joint. Finite element analysis (FEA) is used to perform the simulations. The study is based on a case study involving a HT (&gt; 200 °C) power controller device for a brushless DC motor for downhole applications. The effective strain was found to be high in the bond adjacent Cu layers but reasonably small, &lt; 1%, within the joint itself.
High-Temperature Versatile Voltage-Mode PWM Controller
Authors: Laplace Fabien , Montmayeur Xavier , Thomas Jérôme , Picun Gonzalo 
Published: October 2015

In this paper we present the operation of the XTR30011 device, a high-temperature, versatile, PWM controller with in-specification performance achieved from −60°C to 230°C using a CMOS SOI process. The circuit features a voltage-mode PWM controller that can be used in Buck-mode converters as well as in Boost, Buck-boost, Push-pull and Flyback. Several functional features are implemented including duty-cycle limitation allowing cycle-by-cycle current limitation, hiccup short-circuit protection and complex functionalities for improved efficiency at low load currents.
These advanced features for improved efficiency include automatic synchronous-asynchronous mode transition in Buck-mode, pulse skipping logic with adjustable threshold, low-power mode with capability to receiving the 5V converter output voltage.
Efficiency in DC-DC converters operated at low load currents is dominated by switching as well as intrinsic consumption losses. The XTR3011, in addition to having a low intrinsic current consumption, allows reaching very good efficiencies at low load currents thanks to its functional features.
We present here the operation of several functional features and experimental results across temperature of the efficiency in several configuration modes, and in particular for low load currents.
High Power Lithium Primary Cells for High Temperature Downhole Applications
Authors: Johnson Arden P. , Miller John S. , Wang Yufei 
Published: October 2015

The power demands of downhole tools used in petroleum exploration continue to increase as new instrumentation is added for measurement and for communicating data to the surface. At the same time there is increasing demand for higher temperature capabilities that will allow exploration in hotter formations. As the use of high temperature electronic devices expands, new types of batteries are needed that can provide the necessary power at the higher temperatures.
Here we describe a new lithium alloy primary battery technology that can power downhole tools and other high temperature devices up to 200°C under significantly higher loads than has been possible previously. The higher rate capability of the cell also enables sufficient operation at surface ambient temperatures to allow the functioning of the tool to be assessed at the surface before it is deployed downhole. Cell discharge results over a broad range of temperatures and rates are presented.