bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical selective coating of nickel / palladium / gold metallization on screen-printed thick film on LTCC and Al2O3 ceramic for high temperature applications
Authors: Müller Jens , Mache Thomas , Thelemann Torsten 
Published: October 2015

Electroless plating on silver is a low cost alternative to printing of mixed metals or pure gold paste systems on LTCC. It overcomes the necessity to have material transitions from inner to outer layers or from conductor lines to wire bonding- or solder-pads.
Since no commercial process and material set for silver thick film conductors has been available on the market a proprietary Ni/Pd/Au coating technology was developed for the use on silver inks for LTCC and Al2O3-ceramic as a base for both soldering and wire bonding.
The work included the screening of different chemicals as well as several silver paste systems from two commercial vendors. Conductor adhesion, plating layer thicknesses, plating accuracy, (lead free) solderability and gold wire-bondability were assessed to optimize the process.
Layers of about 5 microns Ni, (0.1 to 0.3) microns Pd and (0.05 to 0.15) microns Au were electrolessly deposited. The developed Ni-Pd-Au finish is an economical alternative with only about a quarter of the cost compared to the conventional use of silver, silver / palladium and gold compounds for ceramic substrates. This technology allows coating of the structures down to a fine pad size of 200×200 microns and a minimum line width of 100 microns, without reducing the adhesion mechanism between thick-film metallization and ceramic substrate.
By covering of pure conductors with high temperature glass or dielectrics, further material saving is possible. Besides, the process offers also very good coating of structures in cavities.
Effect of internal silver conductor on heat spreading capability of LTCC membrane
Authors: Reinlein Claudia , Türke Sascha , Gutzeit Nam , Müller Jens , Peschel Thomas , Burkhardt Thomas , Beckert Erik , Tünnermann Andreas 
Published: October 2015

LTCC membranes are used as substrates of screen printed unimorph deformable mirrors. A high piezoelectric stroke is attributed to thin substrate materials. The application of deformable mirrors with high laser loads calls for a large heat spreading capability of the deformable unimorph mirrors. A large heat spreading capability is attributed to high thermal conductivity of the materials that is not allocated by LTCC. The present paper reports on the effect of internal silver conductor (DuPont 6145) on the heat spreading capability of the LTCC membrane.
Therefore, internal silver conductor is applicated into a 570 μm thin membrane on a diameter of 49.8 mm. The optical absorption of plain LTCC membranes and membranes with internal metallization is characterized by an Ulbricht sphere. Membranes with internal silver conductor and a reference sample without internal metallization (plain LTCC) are loaded with a laser beam. The absorbed laser power heats the LTCC membrane. We investigate the temperature increase upon one-Watt laser loading and prove a 37% lower setting maximum temperature (Tmax) for membranes with internal silver conductor compared to plain LTCC membranes. The characteristics of temperature over time are similar to the charging of a capacitor. The time constant for the internally metallized and plain LTCC membrane at same peak temperatures are similar. These results show the potential of internal silver conductor to increase the heat spreading capability of LTCC membranes.
Evaluation of TFR-Characteristics in aWide Temperature Range
Authors: Partsch Uwe , Lenz Christian , Wenzel Marco , Eberstein Markus 
Published: October 2015

Thick-Film Resistors (TFR) are applied for many years for the manufacturing of ceramic electronic packages as well as for mechanical or thermal sensors. The resistors characteristics (e.g. Rsqr, HTCR, CTCR) are guaranteed by paste suppliers for a thermal range of operation between −55 and 125°C. However, specific sensor applications require higher operation temperatures of up to 500°C.
In the paper the results of the characterization of commercial TFR at elevated temperatures on alumina substrates are presented. Electrical characteristics (e.g. Rsqr, HTCR, CTCR, GF) are correlated with materials characteristics (TFR thermal expansion, glass transition temperature, microstructure). Different requirements are discussed regarding an improved high temperature applicability of TFR. Advantages and limits of the commercial TFR will be presented.
Modeling the Failure Mechanism of Electrical Vias Manufactured in Thick-Film Technology
Authors: Ortolino Dominique , Kita Jaroslaw , Moos Ralf , Wurm Roland , Pletsch Andreas , Beart Karin 
Published: October 2015

Hybrid-thick-film circuits consist of many different components, like screen-printed passive elements (conductors, resistors, and electrical vias), SMDs, and active elements like transistors or ICs. Whereas most of passive components are well investigated and described, the electrical vias often remain unattended. Resistive heating caused by high current pulses might lead to the destruction of the vias. In previous work, we set up a 3d FEM model and investigated the influence of non-radial-symmetric contacting and geometric irregularities of the vias on the occurring maximum temperatures.
The present contribution deals with the modeling of a failure mechanism of an electrical via caused by high current pulses. When the local temperature exceeds a defined melting temperature, the metallization layer melts and is not available for conduction any more. The current density rises as a consequence of the decreased cross section area of the vias and leads to a higher heat production in a smaller area. This conducts further melting of the metallization layer and results in a positive feedback that accelerates the destruction of the via. The approach of this contribution is to model the described failure mechanism in a 2d-radial-symmetric FEM model.
The modeling results were validated using high current measurements of electrical vias. Modeling and measurement of the voltage drop during a constant current pulse agree very well, from very low current density pulses up to pulses that lead to the destruction of the vias.
Joining of Sintered Alumina Substrates and LTCC Green Tapes via Cold Low Pressure Lamination
Authors: Hambuch Michael , Gora Frieder , Beart Karin , Wittmann Frieder , Roosen Andreas 
Published: October 2015

In microelectronics there is a continuous trend for devices of higher integration and improved heat dissipation. For the manufacture of ceramic based microelectronic devices the following technologies can be applied. Thick-film hybrid technology uses sintered ceramic substrates, mostly Al2O3, which are screen printed with functional pastes, followed by firing at 850 °C. Alumina substrates provide very good heat conductivity (25 W/mK), but there are only two sides to carry a metallization. An improved miniaturization can be accomplished by multilayer systems using the LTCC technology. LTCC devices are manufactured by screen-printing, stacking and lamination of ceramic green tapes, followed by co-firing. A drawback of LTCCs is their low heat conductivity (3 W/mK) due to their high glass content. By combining hybrid and LTCC technology the advantages of both methods like good thermal conductivity and high multilayer integration, can be joined.
Because the failure rate is too high to laminate green tapes on sintered ceramic substrates via thermo compression, Cold Low Pressure Lamination (CLPL) has been used as an alternative lamination process. CLPL is a lamination method, where the joining of the components is performed at room temperature by application of very low pressure (&lt;5 MPa) by using a double sided adhesive tape. During heat treatment the adhesive film keeps the tapes together until the adhesive is completely decomposed; during further temperature increase the tapes are joined by sintering. The paper describes the materials used and processing steps to join the sintered material with the green tapes and discusses effects which occur during firing. These effects like edge curl and crack formation are mainly due to stresses which occur during constrained sintering. Their control can be influenced by changing process parameters.
Thick Film Pastes for Power Applications
Authors: Modes Christina , Bawohl Melanie , Langer Jochen , Reitz Jessica , Eisert Anja , Challingsworth Mark , Garcia Virginia , Groman Sarah 
Published: October 2015

Electronic circuits made by thick film technology are commonly used today in electronic circuitry for automotive applications. Densely packed multi-layer hybrid circuits are very well established for motor and transmission management in standard gasoline fuelled vehicles. As automotive technology shifts from mechanical systems to electrical systems and toward more electrically driven vehicles, such as hybrid electric vehicles and full electric vehicles, thick film systems need to be adapted to fit the challenges and needs of these new applications.
The following is a description of a new set of thick film pastes, both precious and base metal, which have attributes and performance suitable for power electronics in automotive applications. The materials provide a means to use common thick film technology to build power circuits to meet the new needs, such as high current carrying capacity and thermal dissipation.
Characterization of the Vectron PX-570 Crystal Oscillator for Use in Harsh Environments
Authors: Li Jacob , Patterson Richard L. , Hammoud Ahmad 
Published: October 2015

Computing hardware, data-acquisition systems, communications systems, and many electronic control systems require well-controlled timing signals for proper and accurate operation. These signals are, in most cases, provided by circuits that employ crystal oscillators due to availability, cost, ease of operation, and accuracy. In some cases, the electronic systems are expected to survive and operate under harsh conditions that include exposure to extreme temperatures. These applications exist in terrestrial systems as well as in aerospace products. Well-logging, geothermal systems, and industrial process control are examples of ground-based applications, while distributed jet engine control in aircraft, space-based observatories (such as the James Webb Space Telescope), satellites, and lunar and planetary landers are typical environments where electronics are exposed to harsh operating conditions.
To ensure these devices produce reliable results, the digital heartbeat from the oscillator must deliver a stable signal that is not affected by external temperature or other conditions. One such solution is a recently introduced commercial-off-the-shelf (COTS) oscillator, the PX-570 series from Vectron International. The oscillator was designed for high-temperature applications and as proof, the crystal oscillator was subjected to a wide suite of tests to determine its ruggedness for operation in harsh environments.
The tests performed by Vectron included electrical characterization under wide range of temperature, accelerated life test/aging, shock and vibration, internal moisture analysis, ESD threshold, and latch-up testing. The parametric evaluation was performed on the oscillator's frequency, output signal rise and fall times, duty cycle, and supply current over the temperature range of −125 °C to +230 °C. The evaluations also determined the effects of thermal cycling and the oscillator's re-start capability at extreme hot and cold temperatures. These thermal cycling and restart tests were performed at the NASA Glenn Research Center. Overall, the crystal oscillator performed well and demonstrated very good frequency stability. This paper will discuss the test procedures and present details of the performance results.
SOI Based Voltage Regulator for High-Temperature Applications
Authors: McCue B. M. , Greenwell R. L. , Laurence M. I. , Blalock B. J. , Islam S. K. , Tolbert L. M. 
Published: October 2015

Developments in automotive (particularly hybrid-electric vehicles), aerospace, and energy production industries have led to expanding research interest in integrated circuit (IC) design toward high-temperature applications. A high-voltage, high-temperature silicon-on-insulator (SOI) process allows for circuit design to expand into these extreme environment applications. Nearly all electronic devices require a reliable supply voltage capable of operating under various supply voltages and load currents. These supply voltages and load currents can be either DC or time-varying signals.
In this work, a stable supply voltage for embedded circuits is generated on chip via a voltage regulator producing a stable 5-V output voltage. Although applications of this voltage regulator are not limited to gate driver circuits, this regulator has been developed to meet the demands of a gate driver IC. The voltage regulator must be able to provide reliable output voltage over an input range from 10 V to 30 V, a temperature range of −25°C to 200°C, and output loads from 0 mA to 200 mA. Additionally, low power stand-by operation is provided to help reduce heat generation resulting in lower operating junction temperature. The designed voltage regulator has been successfully tested from −50°C to 200°C while demonstrating an output voltage variation of less than 10 mV under the full range of input voltage. Additionally, line regulation tests from 10 V to 30 V show a 12-ppm/V supply sensitivity. Full temperature and input voltage range tests reveal that the no-load supply current draw is within 17 mA while still providing in excess of 200-mA load current upon demand. Modifications to the existing design or off-chip biasing can widen the range of attainable output voltages and drive capabilities.
Nanocomposite Film Dielectrics for High Temperature Power Conditioning Capacitors
Authors: Slenes Kirk , Bragg Lew 
Published: October 2015

Emerging power electronics in a broad range of military, aerospace, hybrid vehicle, renewable energy and down-hole drilling applications rely on advances in dielectric materials for capacitors. Compact capacitors possessing low dielectric loss and high operating temperature capability are needed for power conditioning in advanced converter and inverter designs for these applications. Wound film capacitors represent the preferred capacitor technology but are limited by low operating temperature capabilities, &lt; 150°C, and low volumetric efficiency, capacitance per unit volume less than 1.0 μF/cc.
TPL is developing processes and manufacturing techniques for fabrication of advanced capacitor films comprised of high temperature polymers modified with ceramic nanoparticles. The selected polymers enable high temperature operation and the ceramic nanoparticles enhance volumetric efficiency by increasing the dielectric constant. The fabricated films are directly adaptable to conventional wound film capacitor construction methodologies.
This paper provides an overview of TPL's experience to-date with a film dielectric material system comprised of fluorenone polyester polymer and titanate nanoparticle filler. The fluorenone polyester polymer was selected to provide a stable operating temperature of at least 300°C, while the addition of the titanate powder increases the dielectric constant and, in turn, the volumetric efficiency of wound film capacitors constructed with this film system. The targeted device for the film is a 500 to 800 V filter capacitor for high temperature power conditioning applications.
High Temperature CMOS Reliability and Drift
Authors: Rose Shane 
Published: October 2015

Quartzdyne precision pressure transducers are required to continuously operate at 200°C for more than 5 years (&gt;1 year at 225°C). Future electronics are targeted for 250°C operation. The current transducer electronics are based on 3 custom ASICs; an Oscillator, Voltage Regulator and a Frequency counter. Understanding custom integrated circuit component drift and interconnect life at temperature is crucial for the next generation of sensor applications.
In this study, basic components are aged under bias at 225°C, 250°C and 275°C. Components include P-FET transistors, polysilicon resistors, and a diode connected PNP transistor. Measured parameter drift versus temperature and electrical stress is used to estimate device drift over time. Measured voltage regulator drift is compared with estimated drift based on resistor and diode measurements.
Standard aluminum circuit interconnect life is measured at 3 current densities and temperatures. A modified current density guide is derived from Black's equation. Measured circuit interconnect life is shown to increase when diffusion barriers are present. Powered Quartzdyne hybrid circuit life results at 225°C are compared to expected lifetimes.
A System On Chip (SOC) ASIC chipset for Aerospace and Energy Exploration Applications
Authors: Tulpule Bhal , Ohme Bruce , Larson Mark , Behbahani Al , Gerety John , Steines Al 
Published: October 2015

This paper describes the design, key features and applications of a System On Chip (SOC) ASIC (Application Specific Integrated Circuit) chipset which was developed by Embedded Systems LLC as a part of the Smart Node based distributed control system architecture under an Air Force SBIR (Small Business Innovative Research) program {4}. The analog part of the SOC chipset has been implemented by Honeywell International under a subcontract using their high temperature SOI (Silicon On Insulator) Process. The complete chipset is expected to be available in early 2015.
The key feature of the SOC chipset is that it is a reconfigurable and scalable building block that can be used to interface with most typical aerospace control system sensors and actuators. The SOC chipset captures all of the necessary functions required to power and interface with sensors such as RTD (Resistance Temperature Detectors), Strain Gauges (SG), Thermo Couples (TC) and transducers for measuring mass flow, speed, position or angle. The SOC chipset also contains all of the pre- and post-processing functions to convert electrical signals into digital words and send them on a data bus under the control of a host microprocessor. Finally, the SOC chipset contains PWM (Pulse Width Modulation) circuitry required to interface with external drives for actuators, motors, shutoff Valves etc. The SOC chipset can be powered from a Mil-Std-704F compliant power source or a conditioned DC power source. The chipset can be combined with other devices, such as memory, processor and A to D Converter to implement a high temperature capable Smart Node for localized management of sensors and actuators as a part of a distributed architecture or used as a scalable building block in a more complex function such as a FADEC (Full Authority Digital Engine Control). It is believed that the versatility of the SOC chipset makes it a well suited, affordable, scalable building block for not only aerospace controls but also for diverse applications such as down-hole drilling, energy exploration, wind farms etc. where high temperature electronics and /or high level of miniaturization is required.
POL and LDO for Harsh Environment Applications
Authors: Khanna Ramesh , Venkataraman Srinivasan 
Published: October 2015

Harsh Environment approved components/ designs require high reliability as well as availability of power to meet their system needs. The paper will explore the various design constrains imposed on the high temperature designs. Down hole oil and gas industry requires high reliability components that can withstand high temperature.
Discrete component selection, packaging and constrains imposed by various specification requirements to meet harsh environment approval are critical aspect of high-temp designs. High temperature PCB material, PCB layout techniques, trace characteristics are an important aspect of high-temperature PCB design and will be explored in the article. Buck Converters are the basic building blocks, but in order to meet system requirements to power FPGA's where low output voltage and high currents are required. Converter must be able to provide wider step down ratios with high transient response so buck converters are used. The paper with explore the various features of a buck-based POL converter design. Low noise forces the need for Low-dropout (LDO) Regulators that can operate at high Temperatures up to 210°C. This paper will address the power requirements to meet system needs.
Implementation of Silicon-on-Insulator (SOI) Control Electronics to Accelerometers for High Temperature Applications
Authors: Riches S T , White I , Rickard G , Chadwick G 
Published: October 2015

The requirement to install control systems integrated with sensors in high temperature environments has posed a challenge to the traditional limit of 125°C for conventional electronics. There is a need to operate at temperatures of 200°C and above in restricted space for example in down-well, aero-engine or geothermal applications in combination with high pressures, vibrations and potentially corrosive environments.
Piezo-electric accelerometers based on ferro-electric ceramics have been used in a wide range of applications for measuring vibrations, fluid flow and turbulence and are capable of operating as a transducer alone at temperatures up to 250°C, which has made them attractive in sensing applications for down-well drilling and aero-engine health and usage monitoring. However, the electronics traditionally used to carry out the signal conditioning and processing (e.g. charge to voltage conversion, filtering) has been limited to a qualification limit of 125°C, which results in a reduced sensitivity of the transducer output as the signal conditioning and processing cannot be performed close to the sensor.
With the development of Silicon-On-Insulator (SOI) semiconductor technology, which can operate at temperatures of up to 250°C, many of the signal conditioning and processing operations can be carried out in-situ with the accelerometers to create a new generation of high temperature products. In addition, the integration of many of the functions that used to require discrete components into one SOI based device has led to further miniaturisation opportunities and a protection against obsolescence of specialist analogue devices.
This paper will describe the migration of the traditional low temperature electronics to a high temperature SOI based ASIC device and the implementation of high temperature electronics packaging technology to instrumentation for piezo-electric accelerometers, leading to products that are suitable for high temperature monitoring in restricted spaces in down-well drilling and aero-engine applications.