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The paper aims to present the influence of the co-firing process conditions of low temperature co-fired ceramics (LTCC) on the deformation of thin LTCC membranes.

The statistical design of the experiment methodology was used in the frame of these investigations to reduce the time and costs of the experiments and to ensure easier interpretation of the obtained results. Moreover, this conception permits the rough estimation of the membrane deflection fired at optimal process conditions.

The applied design of the experiment methodology allowed the researchers to find the optimal co-firing process conditions and to estimate the membrane deflection at the optimal process conditions. The estimation fits well with the results of real measurement that was conducted to confirm the estimation precision.

The experiment was conducted for only one type of LTCC, DP951. The precision of the design of the experiment optimization and estimation of the response at optimal conditions depend on the described object. Therefore, the findings of this paper do not have to be generally true for other LTCC tapes, and if other LTCC tapes deformation should be investigated, then similar analysis shall be conducted for them.

The deformation of LTCC membranes affects the sensitivity and repeatability of LTCC acceleration and pressure sensors. Hence, the decrease of membrane deflection increases the usability of LTCC in such applications.

This paper presents simple optimization of co-firing process conditions of LTCC devices using statistical design of the experiment.

The United Kingdom (UK) Government is required to meet various renewable energy targets set by the European Union. The UK has had renewables support schemes for many years. It has become clear that the old schemes are insufficient to lead to enough new capacity to meet the target. The government has accordingly reformed the renewables obligation (RO). The purpose of this paper is to analyse whether the reformed RO will meet the targets set for 2015 and 2020.

The paper undertakes a review of the modelling literature and performs a critical, deductive analysis of the RO to answer its research issue.

The paper finds that it is too late to make any difference to the 2010 target, but that the reforms might lead to the 2015 target being met, and finds that whilst it is clear that the reformed RO will lead to more capacity being built than otherwise would have been the case, it is difficult to establish that the 2020 target will be met.

This paper shows that there may be further reform of the already‐reformed RO, and that more time is needed to see the impacts of the recent regulatory responses to the external failures. This understanding will be useful in developing new policies to promote renewable energies in the UK.

The purpose of this paper was to develop the methodology of thick-film/low temperature co-fired ceramic (LTCC) multilayer thermoelectric microgenerator fabrication including the procedure of silver-nickel thermocouples integration with LTCC.

To miniaturize the structures and to increase the output parameters (generated voltage, electrical power), the microgenerator was designed as multilayer systems. It allows to reduce size of the system and to increase the number of thermocouples integrated inside the structure. It also protects buried thermocouples against exposure to harmful external factors (e.g. moisture, oxidation and mechanical exposures). As a substrate, LTCC was used. For the thermocouples fabrication, thick-film pastes based on silver and nickel were chosen. Ag/Ni thermocouple has nearly three times higher Seebeck coefficient and 30 per cent lower electrical resistance than the combination of Ag/PdAg used in previous works of the author.

A multi-layer thick-film thermoelectric generator based on LTCC and Ag, Ni pastes was fabricated. Thirty Ag/Ni thermocouples were precisely screen-printed on few layers. Thermocouples’ arms are 15 mm long and about 150 μm wide. Interlayer connections (via-holes filled with conductive paste) provided the electrical contact between the layers. The biggest fabricated harvester consisted of 90 miniature thermocouples buried inside the LTCC.

The paper presents the results of research that provided to optimize the co-firing process of the LTCC/Ni set. In the result, the methodology of co-firing of silver-nickel thermocouples and LTCC ceramic was elaborated. Also, the methodology of fabrication of miniature thermoelectric energy harvesters was optimized.

The purpose of this paper is to develop the device made of low temperature co-fired ceramics (LTCC) and lead zirconate titanate (PZT) by co-firing both materials. In the paper, the technology and properties of a miniature uniaxial ceramic accelerometer are presented.

Finite element method (FEM) is applied to predict properties of the sensor vs main dimensions of the sensor. The LTCC process is applied during manufacturing of the device. All the advantages of the technology are taken into account during designing three-dimensional structure of the sensor. The sensitivity and resonant frequency of the accelerometer are measured. Real material parameters of PZT are estimated according to measurement results and FEM simulations.

The ceramic sensor integrated with SMD package with outer dimensions of 5 × 5 × 5 mm3 is manufactured. The accelerometer exhibits sensitivity of 0.75 pC/g measured at 100 Hz. The resonant frequency is equal to about 2 kHz. Useful frequency range is limited by 3 dB sensitivity change at about 1 kHz.

Sensitivity of the device is limited by interaction between LTCC and PZT materials during co-firing process. The estimated d parameters are ten times worse comparing to bulk Pz27 material. Further research on materials compatibility should be carried out.

The sensor can be easily integrated into various devices made of standard electronic printed circuit boards (PCBs). Applied method of direct integration of piezoelectric transducers with LTCC material enables manufacturing of complex ceramic systems with built-in accelerometer in the substrate.

The accelerometer is a sensor and a package simultaneously. The miniature ceramic device is compatible with surface mounting technology; hence, it can be used directly on PCBs for vibration monitoring inside electronic devices and systems.

The purpose of this paper is to report on fabrication procedure and present microstructure and dielectric behavior of willemite ceramic material with addition of 5% Li₂CO₃ as a sintering aid.

The samples were fabricated by ball milling of the ceramic powders, preparation of granulate and pressing and co-firing using temperature profile based on heating microscope observation. The dielectric properties of the material were measured by impedance spectroscopy (Hz-MHz), transmission method (GHz) and time domain spectroscopy (THz). The composition and microstructure of the material were investigated using X-ray diffraction, scanning electron microscopy and energy-dispersive spectroscopy analysis. Ceramic powder was used to fabricate a green tape and low temperature co-fired ceramics (LTCC) multilayer structures, which in the next steps of the research were examined at the angle of cooperation with conductive pastes, strength and geometric repeatability.

The fabricated material showed low sintering temperature (920°C–960°C), low dielectric constant 6.2–6.34 and low dissipation factor at the level of 0.004–0.007. As LTCC material, willemite with 5% Li₂CO₃ addition showed good compatibility with AgPd conductive paste.

Search for new materials with low dielectric constant, applicable in LTCC technology, and development of their fabrication procedure are important tasks for the progress in modern microwave circuits.

The purpose of this paper is to investigate and report the impact of glass frit variation in silver thick film pastes used as surface conductors in low temperature co‐fired ceramics technology (LTCC), especially on the properties such as warpage of LTCC associated with conductors, microstructure of the fired thick films, sheet resistance and adhesion on LTCC.

Silver thick film paste compositions were formulated by changing the silver glass frit ratio. The compatibility of these formulated paste compositions with LTCC (DP 951AX) substrate were evaluated. The properties such as microstructure developments, the change in sheet resistance, warpage of LTCC substrate with respect to glass frit ratio of the developed silver films on LTCC were evaluated.

The results reveal that the glass frit percentage used in paste formulation is equally responsible for the disturbance in the properties such as microstructure, warping and electrical properties of the fired thick films on LTCC. It was observed that the paste composition, in particular sample SP10B containing the highest glass frit percentage, is compatible with the LTCC tape under processing conditions. The sheet resistance value in the range of 5 mΩ/□ and the fired films showed very good adhesion (3.95 N), irrespective of the glass frit composition.

The paper provides useful evaluations of properties such as microstructure developments, changes in sheet resistance and warpage of LTCC substrate with respect to glass frit ratio of the developed silver pastes on LTCC.

Modern complex integrated circuits require more input/output connections and operate at faster switching speeds and higher power levels than was the case before LSI and VLSI devices. As a result, there is a need for packages with high electrical conductivity, low dielectric constant, high thermal conductivity, precise line resolution and low unit cost. Ideally, it should also be possible to include resistors and for the package to be manufactured in‐house for maximum control. Multilayer printed circuit boards, complex multilayer hybrid circuits and high temperature co‐fired ceramic packages have been used to accomplish the interconnection of complex ICs. A new technology has been developed which combines the benefits of thick film with the processing advantages of co‐fired ceramic. The thick film process begins with a bare substrate, usually 96% alumina, upon which gold, silver alloy or copper metallisation, and screen‐printable dielectric paste are applied. Processing is a series of printing and firing operations; the firing temperature is usually between 800°C and 1000°C. Interconnecting vias are typically formed by screen printing and are usually a minimum of 250 ?m (10 mil) in diameter. The high temperature co‐fired approach uses no substrate. Printing of tungsten, molybdenum or molymanganese metallisation is carried out on alumina tape dielectric. The vias are formed by mechanical punching and are typically a minimum of 200 ?m (8 mil) in diameter. A single firing is performed in a special atmosphere, usually at 1500°C. This paper describes a new materials system which consists of a tape dielectric and gold, silver and silver/palladium inner layer and via fill conductor compositions. Circuits and packages made with the system are fired in an air atmosphere in standard thick film furnaces and are compatible with other conventional thick film materials. The process for making these parts is described and critical process parameters are identified. The results of reliability testing under temperature, humidity and bias are discussed and supporting microstructural analysis is presented.

The purpose of this paper is to focus on the technology and performance of the miniature microfluidic module for urea determination. The presented module was made using low-temperature co-fired ceramics (LTCC). It shows the possibility for the integration of the bioreceptor layers with structures that have been fabricated using modern microelectronic technology.

The presented microfluidic module was fabricated using LTCC technology. The possibility for the fabrication of an enzymatic microreactor in a multilayer ceramic substrate, made of CeramTec glass ceramic (GC) material systems with an integrated thick-film heater, is studied. Different configurations of the LTCC/heater materials (gold, silvers and palladium-silver) are taken into account. The performance of the LTCC-based microfluidic module with the integrated heater and immobilized enzyme was examined experimentally.

A compatible material for the heater embedded in the CeramTec GC-based structures was found. The preliminary measurements made for the test solution containing various concentrations of urea have shown stability (for seven days of operation) and a relatively high signal-to-noise ratio (above 3 pH units) for the microreactor’s output signal.

The presented research is a preliminary work which is focused on the fabrication of the LTCC-based microfluidic module, with an integrated heater and immobilized enzyme for urea determination. The device was positively tested using a model reaction of the hydrolysis of urea. However, urea concentration in real (biological) fluid should also be measured.

The development of the LTCC-based microfluidic module for urea determination provides opportunity for the construction of a lab-on-chip, or μTAS-type system, for fast medical diagnoses and the continuous monitoring of various biochemical parameters, e.g. for estimating the effectiveness of hemodialysis.

This paper shows the design, fabrication and performance of the novel microfluidic module for urea determination, made with LTCC technology.

The low-temperature co-fired ceramics (LTCC) microfluidic-microwave devices fabrication requires careful consideration of two main factors: the accuracy of deposition of conductive paths and the modification needed to the standard process of the LTCC technology. Neither of them are well-described in the literature.

The first part of this paper deals with the individual impact of screen parameters such as aperture, photosensitive emulsion thickness and mounting angle on the precision of the screen-printed conductive paths fabrication. For the quantitative analysis purposes, the design of experiment method with Taguchi orthogonal array and analysis of variance was used. The second part contains the characterization of the complex permittivity measured for different values of LTCC substrates lamination pressure.

It can be concluded, that the combination of aperture, equal to 24 µm, emulsion thickness 20 µm and mounting angle 22.5° ensures the highest quality of printed conductive metallization. Furthermore, the obtained results indicate, that the modification of the lamination pressure does not affect significantly the dielectric parameters of the LTCC substrates.

This paper shows two aspects of the fabrication of the microfluidic-microwave LTCC devices. First, the resolution of the applied metallization is critical in manufacturing high-frequency structures. The obtained experimental results have shown that optimal screen parameters, in terms of conductive pattern quality, can be found. Second, the received outcomes indicate that the changes in the lamination pressure do not affect significantly the electrical parameters of the substrate. Hence, this effect does not need to be taken into account.

This paper aims to investigate the metallurgical reactions between two commercial AgPt thick films used as a solder land on a low temperature co‐fired ceramic (LTCC) module and solder materials (SnAgCu, SnInAgCu, and SnPbAg) in typical reflow conditions and to clarify the effect of excessive intermetallic compound (IMC) formation on the reliability of LTCC/printed wiring boards (PWB) assemblies.

Metallurgical reactions between liquid solders and AgPt metallizations of LTCC modules were investigated by increasing the number of reflow cycles with different peak temperatures. The microstructures of AgPt metallization/solder interfaces were analyzed using SEM/EDS investigation. In addition, a test LTCC module/PWB assembly with an excess IMC layer within the joints was fabricated and exposed to a temperature cycling test in a −40 to 125°C temperature range. The characteristic lifetime of the test assembly was determined using DC resistance measurements. The failure mechanism of the test assembly was verified using scanning acoustic microscopy and SEM investigation.

The results showed that the higher peak reflow temperature of common lead‐free solders had a significant effect on the consumption of the original AgPt metallization of LTCC modules. The results also suggested that the excess porosity of the metallization accelerated the degradation of the metallization layer. Finally, the impact of these adverse metallurgical effects on the actual failure mechanism in an LTCC/PWB assembly was demonstrated.

This paper proves how essential it is to know the actual LTCC metallization/solder interactions that occur during reflow soldering and to recognize their effect on solder joint reliability in LTCC module/PWB assemblies. Moreover, the adverse effect of using lead‐free solders on the degradation of Ag‐based metallizations and, consequently, on board level reliability is demonstrated. Finally, practical guidelines for selecting materials for second‐level solder interconnections of LTCC module are given.