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Substrates with high thermal conductivity continue to be in great demand for their ability to enable smaller and denser high power circuits. BeO has been used for this purpose for many years with thick film materials. However, due to health and environmental concerns with BeO, many manufacturers feel compelled to switch to alternative substrates. This paper will discuss a thick film system consisting of conductors, dielectric, and resistors developed specifically for use with the most likely alternative, AlN substrates. This system will soon find broad use in applications such as power resistors for telecom, optoelectronic submounts, and high‐power automotive applications.

All capacitor dielectric materials, whether used for discrete or embedded applications, can be grouped into two general categories: paraelectric and ferroelectric. Ferroelectrics generally exhibit much higher dielectric constants, but are also less stable with regard to temperature, frequency, voltage, time and film thickness. There are dozens of each of these materials that have been used in discrete capacitors and about ten that are either available for use in embedded capacitors or will soon be marketed for that purpose. The commercialized materials can be broken down into four sub‐categories: thick‐film polymers, ferroelectric powder in polymer binders, thin‐film paraelectrics, and thick‐film ferroelectrics. These four classifications are evaluated with regard to their electrical performance, ease of fabrication, and suitability for specific applications.

Fired resistors exhibit variations which are minimised by abrasive and laser trimming. The latter may cause unstable behaviour which is further aggravated by thermal shock. The chemical structure of a thick film resistor is analysed with respect to mechanical stress, and the theoretical conclusion that the coefficient of thermal expansion of the resistor should be equal to or smaller than that of the substrate is verified experimentally. The thermal behaviour of ruthenium dioxide is examined and a range of CTE values are determined for materials of varying chemical composition. The relationship between CTE and post laser trimming stability is demonstrated on four thick film resistors which differ in thermal expansion. It is pointed out that formulations with high metallic content can absorb tensile stress by elastic deformation, thus minimising the formation or propagation of laser induced cracks.

The purpose of this work was fabrication of a small energy harvester.

The multilayer thermoelectric power generator based on thick-film and low temperature co-fired ceramic (LTCC) technology was fabricated. Precise paths printing method was used to fabricate Ag/Ni and Ag/PdAg thermocouples on a number of unfired LTCC tapes. The tapes were put together to form a multilayer stack. The via holes were used to make the electrical connections between adjacent layers. Finally, the multilayer stack was fired in the appropriate thermal profile.

It consists of 450 thermocouples and generates output voltage of about 0.45 V and output electrical power of about 0.13 mW when a temperature difference along the structure is 135°C. In the paper, individual stages of energy harvester fabrication process as well as its output parameters are presented.

Miniaturized thermoelectric energy harvester based on thick-film and LTCC technology was fabricated. As materials, metal-based pastes were used. This is the first paper where multilayer thermoelectric harvester, fabricated with the aid of LTCC technology, was described.

The purpose of this paper is to study high-voltage interactions in polymer thick-film resistors, namely, polyvinyl chloride (PVC)-graphite thick-film resistors, and their applications in universal trimming of these resistors.

The authors applied high voltages in the form of pulses and impulses of various pulse durations and with different amplitudes to polymer thick-film resistors and observed the variation of resistance of these resistors with high voltages.

The paper finds that high voltages can be used for trimming of polymer thick-film resistors in both directions, i.e. upwards and downwards.

The research implication of this paper is that polymer thick-film resistors can be trimmed downwards or upwards practically using this method.

The practical implications of this paper is that one can trim the polymer thick-film resistors, namely, PVC–graphite thick-film resistors, in both directions, i.e. upwards and downwards, by using this method.

The value of the paper is in showing that high voltages can be used to trim downwards and also upwards in the case of polymer thick-film resistors. This type of trimming is called universal trimming, developed first time for polymer thick-film resistors.

Thick printing Cu and Ag conductors have been developed specifically for use in power applications where excellent printing, thermal, electrical, wire bonding and soldering properties are prerequisite. Efficient thermal management can require fired films on alumina in excess of 150μm and often printed in large areas. In some designs the thickness of mounting pads alone for bare silicon dies may need to be built up locally. This approach enables a single substrate to comprise both thinner printed, dense circuitry for signal control and thick device mounting pads for efficient thermal management. The flexibility of thickness control, through hole connections and the ability to incorporate printed resistors using standard thick film processing can offer solutions which complement the other substrate technologies in many applications. This paper describes the advancements made in optimizing the performance of thick printing copper and silver conductors designed for use in power applications and their role in this demanding technology. The features of the materials, process guidelines, and performance characteristics will be discussed.

The influence of corrosive gases on the solderability of palladium/silver thick‐film conductors has been investigated. An experimental set‐up for atmospheric corrosion testing has been constructed in which atmospheres can be created comparable to a heavily polluted industrial environment. Various Pd/Ag thick‐film conductors have been submitted for 14 days to flowing atmospheres containing 1 ppm SO2, 15, 0·2 or 0·04 ppm H2S, 1 ppm NO2, 1 ppm O3 and 0·05 ppm Cl2, separately or in various combinations. When used separately, only H2S causes a poor solderability of the thick‐film conductors. This effect on the solderability turns out to be independent of the H2S concentration; even concentrations as low as 0·04 ppm cause identical corrosion phenomena. The other gases mixed with H2S have a synergistic effect on the corrosion process.