bluuebunny/crossref_metadata_2025 huggingface dataset:
Water‐cooled Copper‐clad Invar Hybrid Power Circuit
Authors: Zardini C. , Pistre J.D. , Rodes F. , Aucouturier J.L.
Published: February 2008

Water cooling of hybrid modules allows a power dissipation much higher than that of conventional methods. This paper describes the design and construction of a copper‐clad Invar water‐cooled hybrid power circuit intended for use in a medical hand‐held tool which is a 25 mm diameter cylinder. The thermal study demonstrates the interest of a copper‐clad Invar heat exchanger: water flowing at a rate lower than 15 Ih−1 allows the dissipation of more than 50 W in the module while keeping the external temperature of the tool below 35°C.
ISHM news
Authors: Blancquaert R. , Turnbull Bob , Forster G. , Cullen Lorna , Herod Boguslaw , Muckett Steve , Lawson James
Published: February 2008

ISHM‐Benelux held its 1987 Autumn Conference on 29 October, at the Antwerp Crest Hotel. This one‐day meeting focused on applications of hybrid circuit technology in various fields of electronic and related industries.
Thick Film Superconductors — Preliminary Results
Authors: Hrovat M. , Bernik S. , Kolar D.
Published: February 2008

A superconducting material with the composition YBa1.8Pb0.2Cu3O7 was synthesised. The influence of PbO addition on the sintering and formation of the superconducting compound YBa2Cu3O7 was investigated. A thick film paste, prepared from prereacted material and an organic vehicle, was fired on Al2O3 and ZrO2 substrates. The resistivity of samples on ZrO2 substrates decreased to zero around 90 K, while samples on Al2O3 substrates did not reach zero resistivity until 77 K, which is probably due to the differences in thermal expansion coefficient between Al2O3 and the superconducting material. Interactions between Pt alloy based thick film conductors and superconducting material were studied.
Twenty Years of Neurological Prosthesis‐making
Authors: Donaldson P.E.K.
Published: February 2008

The UK Medical Research Council's Neurological Prosthesis Unit was formed on 1 October 1968. In this review, Peter Donaldson, who has been with the unit from the beginning, reflects on what seem to him to be the most important contributions to implant technology from the unit, and suggests some possible developments for the future.
Photonic Systems Interconnections—Overcoming the High Speed Electronics Bottleneck
Authors: Hartman D.H.
Published: February 2008

Fundamental engineering limits to very high speed electronics switching systems are employed. These limitations are caused by packaging and interconnection constraints, as well as device switching speed. From the device viewpoint, reactive parasitics caused by the packaging/interconnection scenario are discussed. From the systems level perspective, overall delay, delay variance and power consumption are explored. The important problem of clock distribution in high speed synchronous digital systems is discussed. These limitations are then revisited with photonics implementation in mind. Comparisons are made between the electrical and photonic approaches. Some engineering limits to the photonic alternative are laid out.
Discrimination of Chemical Compounds and Functional Groups by Pattern Recognition Using an Integrated Sensor
Authors: Oishi T. , Kaneyasu M. , Ikegami A.
Published: February 2008

An integrated sensor with three elements (zinc oxide, tin oxide and tungsten oxide) was fabricated by thick film techniques in order to develop a smell sensor. Using this sensor and pattern recognition method, the possibility of identifying 15 chemical compounds which belong to the alcohol, ester, ketone, benzene and hydrocarbon group was examined. The following results were obtained: All 15 compounds have different patterns, so they can be individually identified; compounds which have the same functional groups have similar patterns; and, when gas sensitivity of three elements is displayed in a three‐dimensional space, the compounds with the same functional group form a specific closed space. This indicates that the sensor can identify functional groups of chemical compounds.
Present State of Directly Solderable Copper PTF
Authors: Tsunaga M. , Kato S.
Published: February 2008

This paper describes a newly developed Copper PTF (Polymer Thick Film) which is characterised by direct solderability and high electrical conductivity. This Copper PTF claims to solve various problems existing in the conventional subtractive or firing process. It also realises new circuit production processes which are difficult to attain if conventional methods are applied.
Accelerated Life Test of Thick Film Resistors
Authors: Golonka L. , Kozlowski J. , Nitsch K.
Published: February 2008

The rapid assessment of thick film resistor reliability is presented. This relies on the application of constant power pulses. The long‐term stability of the resistors is predicted on the basis of the value of the minimal destroyed power applied during the pulse. The results are compared with the long‐term behaviour of the tested samples.
Two Thick Film Thermal Sensors
Authors: Kwikkers T.
Published: February 2008

For the production of sensor elements, thick film technology can be used. Advantages of this technology such as ease of production, low cost, high reliability and the possibility of integration with front‐end electronic circuits, make the thick film sensor an interesting alternative to existing sensor elements. In this paper two examples of thick film thermal sensors are presented.
The Surfactant Flux—A New Flux for the Ozone Age
Authors: Becker G. , Biverstedt A. , Tolvgård A.
Published: February 2008

The development of a new type of flux—the surfactant flux—is described. This flux is applied in a very thin layer and must be totally dry before soldering. It is not necessary to clean PWBs after soldering for functional or aesthetic reasons. Even the results of the surface insulation resistance (SIR) test suggest no need for cleaning. The flux allows a very high soldering speed, at least double that of normal fluxes. Thus the heat input into the materials involved is minimised, with the consequence of less damage. It is not the chemicals which make the flux highly active but the concept. This new concept makes it possible to design non or low corrosive fluxes in a wide range for purposes where highly corrosive fluxes must be used today.
Nokia Electronics, Helsinki, Finland
Authors: Turnbull R.B.
Published: February 2008

Scandinavia is always one of my favourite destinations for a number of reasons. First of all, I like the cleanliness of the atmosphere which certainly helps to keep one fresh at the end of a long day. Then on some days it gives that incredible clarity and luminosity so admired by artists and which in turn may have led to the clean lines of Scandinavian design. The striking memorial to Sibelius is a tribute to both Finnish design and her most famous musician. In fact, ‘Finlandia’ is the first piece of classical music I can remember and 1 first heard it on earphones using a crystal set. In those days virtually all receivers were hand made, even to hand‐wound coils. Loud‐speakers were an expensive rarity.
ISHM news
Authors: Kwikkers T. , Lantaires J. , Turnbull R.B. , Law H.T. , George Barry , Savage Dave
Published: February 2008

On 20 April ISHM‐Benelux held its 1988 Spring meeting at the Grand Hotel Heerlen. This meeting was totally devoted to implantable devices, in particular to the technologies used for these high reliability, extremely demanding devices. For this meeting ISHM‐Benelux was the guest of the Kerkrade facility of Medtronic. Medtronic (headquartered in Minneapolis, USA) is the world's leading manufacturer of implantable electronic devices. Apart from the assembly of pacemakers and heart‐wires, the Kerkrade facility acts as a manufacturing technology centre for Medtronic's European facilities.
Industry news
Authors: Turnbull R.B.
Published: February 2008

ITS: Intertrade Scientific Ltd, the UK based manufacturer of the MCT/Browne InfraRed Reflow Soldering Systems for SMT and Hybrid applications, as part of their aggressive drive into Europe, has announced the signing of a distributor agreement with Maquinaria Suiza SA of Spain. Under the agreement, Maquinaria Suiza will be the sole supplier of the highly successful product range to Spain and Portugal.
Solid State Physics—1947
Authors: Bardeen J.
Published: February 2008

This article was part of a commemorative section in Solid State Technology entitled ‘The Transistor—The First Forty Years’, which celebrated the 40th anniversary of the December 1987 invention of the transistor at Bell Telephone Laboratories.
Thermal Studies on Hybrid Circuits
Authors: De Mey G. , Rottiers L. , Driscart M. , Boone E. , Van Schoor L.
Published: February 2008

In this paper the temperature distribution in hybrid circuits will be studied in two different ways. First of all the results of numerical simulations obtained with the programs PROMETHEE and HYBRITHERM will be shown. Secondly, experimental temperature plots obtained with infra‐red thermography will be compared with the theoretical results. The influence of the substrate material (epoxy, glass, Al2O3, AlN and BeO) on the temperature distribution will be demonstrated. Various ways of cooling will also be considered. It will be shown that using high quality substrates such as AlN or BeO is not always useful from a thermal point of view.
Eliminating Electronic Component Stresses through Controlled Laser Soldering
Authors: Vanzetti R. , Traub A.C.
Published: February 2008

A procedure is discussed wherein an infra‐red detector is used for controlling the quality of solder joints being formed by laser‐beam heating on printed circuit boards while, at the same time, automatically inspecting the quality of each joint. The joint‐by‐joint soldering method avoids the thermally induced stresses between the components and the printed circuit board which can occur when the entire board is mass soldered by conventional means. It also eliminates the ‘after the fact’ human inspection process, while at the same time making available real‐time data for process control of the soldering operation.
CMOS Gate Array Design
Authors: McGrail J.M.
Published: February 2008

Software tools are an essential part of any IC design system but there are dangers associated with the introduction of CAD systems. This paper attempts to lift the software cloak which, along with the ubiquitous workstation, tends to cover the finer points of CMOS design. This paper should help to make the designer or user of gate arrays more aware of the important features such as power dissipation, the use of transmission gates, latch‐up prevention, the pitfalls of using circuit simulators, and the importance of selecting the correct package.
Photoconductivity of Thick Film Resistors
Authors: Parravicini G.B. , Samoggia G. , Morten B. , Prudenziati M.
Published: February 2008

A weak change of resistivity caused by visible radiation both for commercial and for model thick‐film (cermet) resistors (TFRs) has been observed and studied in the temperature range 10–380 K. A possible origin of this photoelectric effect in terms of photoexcited electrons emitted from the metallic grain surface into the glassy region is discussed.
Analysis and Synthesis of Thick Film Resistors Using EGET Principles
Authors: Aleksić O.S. , Nikolić P.M. , Todorović D.M.
Published: February 2008

A new model for thick film resistor calculation accounts for the physical effects which make variations in local sheet resistivity and local volume resistivity: geometry and terminal diffusion effects. Taking the criterion of homogeneity in the observations of local resistivity, a resistor is transformed geometrically and electrically into equivalent modular parts. Comparing the resistor transformed by equivalent geometrical and electrical transformation (EGET) with an ideal resistor a new semi‐empirical formula for thick film resistor calculation was evaluated. This model takes into account the technological process which makes possible more accurate resistor projection compared with other models.
Thick Film Resistors Not Only on Ceramics: How to Obtain Suitable Layout Parameters
Authors: Stecher G.
Published: February 2008

The square resistance of thick film resistors on dielectric layers can show a very complex behaviour. From resistance measurements of a test pattern three suitable paste parameters Q(L), M(L) and A(L) can be calculated as numerical functions of the resistor length L. All formulae needed for establishing an accurate resistor layout by means of the parameters are presented in this paper. The three‐dimensional surface of the square resistance as a function of length L and width W can also easily be calculated.
Thermal Design Considerations for COB Applications
Authors: Estes R.C.
Published: February 2008

As requirements for system performance and density increase, more attention is being given to chip‐on‐board (COB) packaging techniques. COB is ‘surface mount packaging taken to the extreme’ as it involves the direct mounting of bare semiconductor die to printed circuit board substrates. In this paper, the ‘thermal resistance’ of a single COB package is proposed. An analytical model for this resistance is developed for a multilayer board configuration using a combination of Fourier transform and adjoint‐solution techniques. Parameters in the model include the chip and board geometric parameters, individual layer unit conductances, and top and bottom surface film coefficients. A series of curves are developed from the model. These curves may be used in the initial design process to determine, for example, required film coefficients and the efficacy of adding thermal planes to the board. The model is also used to test the adequacy of the ‘effective series conductivity’ of a multilayer board.
Electronic Packaging in Japan
Authors: Wheeler J.
Published: February 2008

We hear much about the Japanese and their dominant position in electronics. Attention is focused on their superior production techniques, automation, high reliability and low prices. This report covers a seminar which was the culmination of a DTI sponsored study mission to Japan in November 1987 to assess the status of electronic packaging technology there.
ISHM news
Authors: Lantaires J. , Forster G. , Setty M.S. , Sinnadurai Nihal
Published: February 2008

The venue for this year's ISHM‐Benelux Autumn Conference and ‘table‐top’ display meeting on 12 October will be the Institut Supérieur Industriel de l'Etat, Mons, Belgium.
Industry news
Authors: Tait Richard , Turnbull R.B.
Published: February 2008

Kulicke and Soffa Industries, Inc. have announced the appointment of Dr Arthur J. Schneider as Vice President of Research and Development. Dr Schneider is based in Willow Grove and reports directly to Donald R. VanLuvanee, K & S President.
The Design Process for Application Specific Integrated Circuits (ASICS)
Authors: Tonge J.D.
Published: February 2008

This paper presents an overview of the ASIC design cycle, and covers the main topics involved in the successful translation of an ASIC concept into a chip capable of exploitation in volume manufacture. Many points are emphasised, which, in the author's opinion, form part of a sound design methodology. However, there can be no one unique formula for all of the points considered, as each ASIC development will have its own particular technical and commercial environment, which in turn will influence decision making in some of the key areas discussed.
Silicon Integration and Its Impact on the Hybrid Industry
Authors: Topham D.
Published: February 2008

Rapid advances in silicon, including ever higher complexity and easier access to customised approaches, are forcing dramatic changes in electronic equipment design and manufacture. This paper examines the developing role for hybrid microcircuits and concludes that hybrid technology, often thought of as optional, should now be regarded as an essential partner for monolithic silicon technology.
Integrated Magnetics Components Using Thick Film Hybrid Technology
Authors: Aitmani N. , Ousten Y. , Aucouturier J.L. , Michaux D. , Mas P.
Published: February 2008

Recent advances in solid state power conversion, specially in the high frequency domain, have shown the need for magnetics components for hybrid circuits. This paper describes the design and realisation of thick film inductors and transformers using a ferromagnetic ink. A square inductor has been modelled and its magnetic behaviour simulated by using the ANSYS program.
Packaging for Thermal Detectors
Authors: Robinson M.K. , Shorrocks N.M. , Bicknell R.W. , Watson P. , Pedder D.J.
Published: February 2008

A new lass of sensors for thermal imaging and detection in the infra‐red band is emerging which exploits the pyroelectric effect in ferroelectric materials. These sensors, which are fabricated in the form of large linear or two‐dimensional arrays of detectors interfaced to a silicon readout circuit, do not require cooling for their operation, in contrast to the photon detection based thermal imagers. They thus have the potential for low cost thermal detection and imaging. This paper examines the design of these arrays and the technologies employed in their fabrication, with particular attention to their specialised packaging requirements, by reference to a range of linear and two‐dimensional pyroelectric array devices that have been fabricated in this laboratory.
Experience with AlN Substrate
Authors: Feil M.
Published: February 2008

The similarity of its temperature expansion coefficient to that of silicon, as well as its high thermal conductivity, makes AlN a material suited for application in microelectronics. A comparison of the various AlN manufacturers shows above all differences in the choice of sintering aids and the type of sintering process. A comparison of a standard paste system (Du Pont) with a new special development (Shoei) demonstrates the need for adapting the pastes to AlN ceramics. Thin film technology is possible at a standard similar to that of Al2O3.
Hybrid Microelectronics and the Market Opportunities in Europe
Authors: Sinnadurai N.
Published: February 2008

In order to identify and quantify the size and shape of the rapidly changing complexion of the market for hybrid microelectronics, in 1987 ISHM launched a survey in Europe of the market for thin‐film, thick‐film and surface‐mount‐on‐PCB hybrids for the periods 1980, 1986 and 1990. The survey aimed to obtain a hierarchical breakdown of the markets also into technology and application sectors. The general findings are reported. The credibility and quantity of the survey are considered in the context of the market for electronic equipment in Europe for 1987 and 1990. In electronics there is a continuing pressure to reduce prices and therefore adjustments should not be made for inflation. A growth in market value is thus a true reflection of a larger growth in market volume and a continuing increase in complexity. Thus, the 11% CAGR for 1986–1990 reflects a growth in equipment volumes of 20% over the 4 year period. Manufacturers will have to design and build increasingly complex circuits at a higher throughput and lower cost, at an increasing pace. It is not a business for faint hearts. Clearly the growth potential for the hybrid microelectronics market should be considered in the context of the equipment market, in order to judge the relative growth. In order to distinguish between the hybrid and PCB industries, the survey has aimed to estimate the growth in the developing market for hybrids using substrates up to 6 in. × 4 in. (Eurocard), not including the larger SMAs on PCBs for which there is a huge market growth potential. The immediate opportunity is from miniaturisation and cost reduction using hybrid microelectronics. The major push in technological emphasis in modern hybrids comes from the need for high‐density interconnection to support increasingly complex VLSI in high‐pin‐count surface‐mount micropackages and high‐performance substrates to support VHSIC and high‐performance circuits. Hence there is a major shift in hybrid microelectronics technology emphasis towards high‐density surface‐mount assemblies on PCB and other organic substrates. The total hybrid market sub‐divided among the basic three technologies reveals this emphasis. The portents are clear, and those who intend to succeed, or even simply survive, need to be aware of the shift in emphasis and prepare to diversify or establish strengths in niche applications.
Some Adhesion Aspects of Thick Film Conductors
Authors: Storbeck I. , Leitner G. , Wolf M. , Gottschalk P. , Schläfer U.
Published: February 2008

An attempt is made to discuss the adhesion of thick film conductors on ceramic substrates in connection with thermally induced internal stresses caused by mismatch of the thermal expansion coefficient of the various layers and the substrate. The curvature of the bent substrates was taken as a measure of the internal stresses. A theoretical multilayer model is proposed for description of the composite — substrate/conductor/solder/intermetallic phases. This permits estimation of the stresses and the Young's modulus within the layers and explains the decrease of adhesion of the soldered copper layer after ageing.
Processing and Diagnostics for Thick Film Superconductors Produced from Y‐Ba‐Cu‐O Materials
Authors: Choi J.S. , Bhalodia M. , Samph S. , Snowden P. , Yahner P. , Scoles K.J.
Published: February 2008

Thick film superconductors have been produced by screen printing and annealing pastes made from oxide powders and pre‐annealed powders. These films have been analysed by X‐ray diffraction, microwave absorption, resistance vs. temperature measurements, and adhesion tests. Results show the correlation between structural and electrical properties.
The Possibilities for Applying Superconductive Ceramics to HMT (Hybrid Microelectronics Technology)
Authors: Miyashiro F.
Published: February 2008

Superconductive ceramics, at present, have not yet grown into a practical material for actual application to devices and systems, but are still in the raw material stage within the research laboratory. This paper will discuss some application possibilities in Japan to the HMT field: LSI wiring, transistors, hybrid ICs, and packaging, from electrical, physical and chemical aspects, supposing that only such superconductive ceramics as Y‐Ba‐Cu‐O(YBCO) and Bi‐Sr‐Ca‐Cu‐O(BSCCO) under liquid nitrogen cooling can be used.
Will ASIC Technology Demand a New Interconnection Technology instead of Soldering in Automotive Electronics?
Authors: Danielsson H.
Published: February 2008

Automotive electronics, after 1995, will be similar to aerospace electronics because there is a demand for low weight and volume together with very high speed and ultra‐high reliability. What is different is that automotive electronics must achieve all those properties at very low cost. It will be shown that when using ASIC chips the chip area is determined by the number of pins instead of the number of components of the active circuit. As ASIC technology proceeds towards line widths in the submicrometre range, the ratio of active Si area to total chip area is becoming much less than 1. This means that on the ASIC chip there is Si area which is ‘empty’. This ‘empty’ Si area can be used for designing self‐test circuits and redundant functions on the ASIC chip at a cost penalty slightly higher than the design cost. It will also be shown that these ASICs can work in the order of 100 MHz at the chip level. Such ASIC chips will therefore have a very high reliability at the chip level due to the inherent properties of the Si and the built‐in redundancy. At the same time they can work at very high speed. From a performance point of view the best solution should be a highly miniaturised packaging technology. With self‐test circuits on the chip, there is a good correlation between wafer test and final test. Therefore, from an economical point of view, working with chips will then have an economical advantage compared with working with packaged circuits. From a reliability point of view it will be shown that the solder joints are the limiting factor. A critical review is presented of the reliability problems plaguing the SMD and soldering technology of today. It will be shown that, if SMD technology is to meet the reliability demands in a future automotive environment, it will have to have solder joint failure rates better than 30 ppm over the life, 17 years, in automotive applications. The conclusion is that a multi‐ASIC chip approach has the best potential as the solution for the future, post 1995, automotive electronics, provided there is a highly reliable chip interconnection technology available at that time.
The Current Situation of Japanese Hybrid Microelectronics
Authors: Kunioka A.
Published: February 2008

The status and the problems of HMT (hybrid microelectronics technology) in Japan are reviewed, and a market survey for Japan is presented.
Cooling of Hybrid Circuits with Fluorocarbon Liquids
Authors: De Mey G. , De Vrieze L.
Published: February 2008

The possibilities of liquid cooling in electronics is briefly discussed. A particular application of hybrid circuit cooling is presented. Emphasis is placed on the fact that the liquid circulates under natural convection in a hermetically closed package. The module can then be used in various circumstances.
The Rôle of the Semiconductor Industry in Hybrid Technology—A Tutorial
Authors: Griffiths G.W.
Published: February 2008

Whatever one may feel is the importance of particular interconnection and assembly technologies with which one is associated, Thin Film or Thick Film Hybrid, PCB Through Hole, Surface Mounting, etc., the driving force in electronics is the high degree of low cost functionality brought by semiconductor technology. However, semiconductor science cannot provide systems solutions on its own and needs to be combined with suitable interconnection and assembly technologies to bring its potential processing power to fulfilment. Hybrid technology holds a key role in the use of silicon in overall system integration. On hybrid substrates semiconductors can be applied in any of the forms available, from bare dice to encapsulated, tested and burnt‐in complex functions in LSI. Over the years hybrids have developed, needing semiconductors as the active elements in providing functional modules. The relationship between the technologies has been close but not always in perfect harmony at the commercial interfaces. The first part of this paper reviews development of semiconductors in relation to the forms of packaging available for application in hybrid assembly including the emergent means being adopted to tackle the problems of ever increasing lead counts that will be with us for some time until the dream of total self‐sufficiency on silicon becomes a reality. The second part of the paper reviews silicon design options with the emphasis on the relevance of combining silicon implementation with hybrid methods.
A Comparison of Electrodeposited Tin and Tin/Lead Coatings on Nickel Barrier Terminated, Multilayer Ceramic Chip Capacitors
Authors: Kucera M.
Published: February 2008

Nickel, as a barrier to the dissolution of termination materials, requires a solderable coating to prevent nickel oxidation and preserve solderability of surface mount devices. Most multilayer capacitors (MLCs) are supplied with tin or tin/lead coatings electrodeposited over the nickel barrier layer. There is general disagreement in the electronics industry about preferred solderable finishes and solderability test methods of component leads. Tin and tin/lead finishes have typically been compared on leaded devices. The results of these studies are not necessarily applicable to leadless surface mount chip components. This study compares 100% tin and 60/40 tin/lead electroplated coatings on nickel barrier terminated, multilayer chip capacitors (MLCs). Various thicknesses of tin and tin/lead were compared for solderability after steam‐age, solder joint strength, and chemical and physical composition of the reflowed termination surface. The results show no significant difference between the solderability and joint strength under vapour phase reflow conditions using 60/40 solder paste. The termination surfaces were reflowed at 215°C in the case of both pure tin and 60/40 tin/lead. The tin/lead finish reflowed to a composition of 60% tin/40% lead. The 100% tin finish reflowed to a composition of 90% tin/10% lead. Reflow was caused by diffusion of lead and tin.
Screen Printed Thick Film Resistors — Better Yields with Shorter Set‐up Times
Authors: Giani E. , Mathurin J.P.
Published: February 2008

A set of rules is presented for printing thick film resistors, whose implementation minimises losses due to resistors firing too high or too low, and also results in the shortest possible set‐up times. To the best of the authors' knowledge, some of the concepts and relations reported here are nowhere to be found spelled out in the published literature, let alone presented in quantitative form. One example is the relationship between sheet resistance vs resistor length curves and the mesh/emulsion of the screen used to obtain such curves. Another example is the relationship between the choice (or lack of it) of resistors used to set up thickness at the beginning of a print, and the spread in resistance values. Then there are better known relationships, like the dependence of thickness on resistor width or print direction—still no quantitative data are available and the potential relevance of these effects is generally not appreciated. Long set‐up times and yield losses need not exist, as they arise from non‐rigorous printing rules which call for a standard dry thickness (usually 25±3 µm) regardless of resistor dimensions, print direction and ink jar value, and which only call for a range of screen mesh/emulsion values, rather than for specific ones. In fact, for any given sheet resistance vs resistor length curve, only one choice of screen mesh/emulsion and resistor thickness is logically possible. Also reported are experimental data relating resistor thickness to resistor length as a function of screen mesh/emulsion, resistor width and print direction as well as data on sheet resistance as a function of resistor dry thickness. Finally, results from thirty‐eight production runs are reported and discussed.
A Single Substrate Thick Film Temperature Datalogger
Authors: Pullman R.T. , Van Kuyk P.F. , Jenness C.A.
Published: February 2008

During the transport of perishable goods it is important to ensure that optimum temperature storage conditions are observed. To ensure compliance to these conditions a miniature temperature data logger has been developed that can be included in the consignment to sample and record the temperature of the goods in storage and transit. The recorded information can later be retrieved and processed by computer when the goods reach their destination. To meet the required specifications (size and weight in particular) the data logger was constructed using thick film hybrid circuitry built onto a porcelain enamelled steel (PES) substrate plus the use of a custom gate array. The design concept of the data logger and its construction are described and various problems experienced with the PES technology are discussed.
ISHM news
Authors: Law Hamish
Published: February 2008

Dates: 29–31 May 1991 Venue: De Doelen Conference Centre, Rotterdam, The Netherlands The Benelux Chapter of the International Society for Hybrid Microelectronics will be organising the 8th European Microelectronics Conference. The event will take place at ‘De Doelen’, Rotterdam, The Netherlands, from 29 to 31 May 1991.
Industry news
Authors: Turnbull B.
Published: February 2008

Jenny Wheeler has recently joined PRTM Ltd, an international operations management consultancy company offering implementation orientated support to high technology industry. PRTM Ltd has considerable experience in streamlining the manufacturing, distribution and services process. Jenny has joined to strengthen their rapidly expanding service in the area of Product Development/Time‐to‐Market, where they have currently helped clients achieve reductions in product development cycle times by more than 50%.
Excimer Laser‐induced Etching of Semiconductors and Metals
Authors: Peyre J.‐L. , Rivière D. , Vannier C. , Villela G.
Published: February 2008

As the feature sizes of microelectronic and optoelectronic components continue to decrease, there has been increased interest in developing new techniques for etching the materials used to construct these highly integrated components. Features of the new techniques now being investigated include etching with neutral species, maskless processing, material selectivity, and reduced electrical damage.
Application of Laser Technology in Drilling and Scribing Low Temperature Cofired Ceramic
Authors: Tudanca M. , Gonzalez R. , Ortega N.
Published: February 2008

The new Low Temperature Cofired Ceramic process combines the advantages of thick film standard and cofired ceramic technologies for the implementation of high interconnection density hybrid circuits, at a reasonable cost. Due to the wide diversity of devices required in the telecommunications field, it is important to have for drilling and scribing a system capable of being easily integrated onto a LAN, in order to reduce the machine preparation time, using all the information already existing in CAD. As laser systems are standard in thick film production, the investments involved to implement a new technology are minimised. This paper describes the use of laser technology for drilling green ceramic to achieve interconnection paths between different levels, manufacturing of screen mask (via metallisation), and scribing of substrates already synthesised. A preliminary characterisation of Telettra's technology follows.
Thin Film Hybrid Circuits on AIN Substrates
Authors: Bostelaar L.J. , Vander Auwera D. , Gys F.
Published: February 2008

The compatibility of available AIN substrate materials with thin film metallisation processes is briefly discussed. The AIN material is shown to be covered with a very thin oxide layer. NiCr and NiCr‐Ni‐Au layers have been deposited onto the substrates; the adhesion between these layers and the ceramic is tested. In the substrate, via‐holes have been made by laser drilling, and the influences of the ambient gas atmosphere on the creation of such via‐holes have been observed. Advantages and limitations of the different methods of producing via‐holes that can be metallised are discussed. A high density hybrid circuit module on AIN is demonstrated.
The Use of Silver as an Alternative to Copper in the Fabrication of Reliable Thick‐film Hybrid Microcircuits Requiring High Conductivity Conductor Tracks
Authors: Videlo I.D.E. , Sutherland R.R.
Published: February 2008

It is proposed that reliable multilevel thick‐film conductor interconnect, having high track conductivity, can be fabricated with conventional air‐firing thick‐film materials, by combining the high conductivity of a pure silver conductor with the solderability of a palladium‐silver conductor. Thick‐film conductor interconnect fabricated in this manner was shown to meet comfortably the stringent requirements of a 20 year service life. A development in the standard technology used to obtain high conductivity interconnect, nitrogen‐firing copper thick‐film materials was also evaluated. It was found that new lower porosity dielectrics may allow copper thick‐film conductor interconnect to be as reliable as the air‐firing alternatives. The activation energy for the process of silver migration through a thick‐film dielectric in a humid environment was found to be in the region of 0.6 eV. The accelerating influence of humidity was also measured.
Soft Guard—A Method of Trimming Resistors in Closed Loops
Authors: Lenk P.
Published: February 2008

The automatic laser trimming of resistors is highly developed, but some areas of application still allow improvements. The method described is a new development for trimming resistor networks. When resistors within a network have to be trimmed, the influence from the other resistors has to be compensated in order to obtain a correct measurement (e.g, π‐network). Normally this is achieved with an Active Guard circuit, but new generation laser trimmers also offer an entirely mathematical compensation called Soft Guard.
Flexible High Performance TAB Inner Lead Bonding with a Laser
Authors: Spletter P.J. , MacKay C. , Jee Y. , Galanakis C.T. , Luijtjes N. , Woodard O.C.
Published: February 2008

MCC has been developing the use of flashlamp pulsed Nd:YAG laser technology to bond TAB leadframes to bumped IC die. With basic equipment, the process has been proven in a laboratory scale environment. As a result, MCC recently licensed a vendor to manufacture the equipment so that it can be used in prototype and later in production environments. This project was initiated to develop a benign alternative for thermocompression gang bonding, particularly for applications where IC bond pads would be located over active circuitry. In addition, because the laser beam's positions are computer controlled, the process has shown to be very desirable for bonding conventional devices with peripheral pads, especially in high product mix applications. Bond rates of 40 bonds/second have been demonstrated at MCC. The first production prototype will bond at 60–80 bonds/s and it is anticipated that, with further development, the full production equipment will bond at 200 bonds/s. The process that is most mature at the time of writing is for bonding tin plated copper leads to gold bumps. This system allows formation of reliable bonds because the formed bonds consist primarily of copper and gold. The bonds are at least as strong and reliable as with other methods of TAB bonding. Bonds with this metallurgical system have been subjected to severe environmental testing without failure. This paper will present results of laser inner lead bonding, the equipment used to develop it and the expectations of the future equipment as well as the future of the technology itself.
Thermal Analysis in CAD of Hybrid Circuits
Authors: De Mey G.
Published: February 2008

In this contribution a short review is given on thermal analysis of hybrid circuits using 2‐D, 3‐D and time‐dependent models. It will be shown which models are necessary to be included in a CAD system for hybrid circuit design.
Research into Optoelectronic Components
Authors: Hildebrand O. , Benoit J. , Duda A.
Published: February 2008

Optoelectronic components such as lasers and avalanche photodiodes have already revolutionised long distance transmission, and yet the technology is still in its infancy. Future generations of optoelectronic components will see the increasing integration of electronic, optoelectronic and optical functions on single chips, bringing about dramatic improvements in performance and the lower costs that will be required for widescale introduction of broadband networks and services.
Thermal Resistance and Temperature Cycling Endurance of DCB Substrates
Authors: Martin W. , Waibel B. , Laaser W.
Published: February 2008

Automotive ignition modules are constructed employing power transistors which are soldered to metallised ceramic substrates to achieve electrical insulation and good heat dissipation. Research activities were aimed to substitute potentially hazardous BeO ceramics by means of DCB substrates using non toxic Al2O3. To fulfill reliability requirements as well as thermal conductivity specifications, the DCB compound has to be optimised with regard to thermal stresses, material properties and interconnection technology. Complementary, appropriate test criteria have been established to characterise the performance of DCB substrates in the ignition module.
The Use of Thermal Imaging to Assess Electronic Components
Authors: Gionis N. , Campbell D.S.
Published: February 2008

An investigation involving the use of thermal imaging has been undertaken, both on trimmed thick film resistors and on wave soldered joints to surface mounted devices. The surface mounted devices were ‘zero‐ohm’ jumpers which in themselves did not generate appreciable heat if current was passed through them, but also at the same time allowed the passage of DC current flow through the soldered joints. Thermal imaging results have shown the degree of current bunching obtained for thick film resistors trimmed using air abrasion. Appreciable changes in heating and hence in current density are not observed until the resistor has been trimmed with a cut extending into approximately 50% of the total width. In the case of soldered joints on surface mounted devices, it was found that thermal imaging techniques could not easily detect appreciable temperature changes and hence the current flow in joints which had previously been subject to stress due to one test or another. As a result, measurements were made on artificially damaged joints in order to determine the degree of damage that was needed for thermal imaging to show any noticeable effect. The joints were cut with a miniature PCB saw (1 mm wide) and it was not until the cut extended through approximately 60% of the soldered joint height that any appreciable thermal effects could be observed. Conclusions are drawn from these observations on the applicability of thermal imaging techniques to the assessment of trimmed resistors and soldered joint analysis.
A New Approach to the Study of the Intrinsic Ageing Kinetics of Thick Film Resistors
Authors: De Schepper L. , De Ceuninck W. , Stulens H. , Stals L.M. , Vanden Berghe R. , Demolder S.
Published: February 2008

A new method of studying the accelerated ageing of interconnection materials is applied to a high‐stability thick film resistor system (the Du Pont HS‐80 system). The new method, referred to hereafter as the in‐situ method, allows measurement of the electrical resistance of a thick film resistor to a resolution of a few ppm during accelerated ageing. With the in‐situ technique, the electrical resistance measurements are performed at the elevated ageing temperature during the ageing treatment, whereas with the conventional ageing method the resistance measurements are carried out at room temperature, between subsequent annealing steps. The measuring resolution obtainable with the in‐situ method is orders of magnitude better than with the conventional method. The ageing kinetics can therefore be studied on a shorter time scale and in greater detail than with the conventional method. In this paper, the authors use the in‐situ method to study the accelerated ageing of the Du Pont HS‐80 thick film resistor system, encapsulated with a proper glaze. It will be shown that kinetics of the resistance drift observed in this system cannot be described by an Arrhenius‐type equation. The ageing data can only be interpreted in terms of a kinetic model incorporating a spectrum of activation energies for the ageing process. Such a model is given, and is shown to provide a good explanation of the observed ageing behaviour. The physical process that causes the observed ageing is most probably diffusion of silver from the contacting terminals into the amorphous matrix of the thick film resistor.
Center for Advanced Ceramic Technology, Alfred University, Alfred, New York, USA
Authors: Spriggs Richard M.
Published: February 2008

The dawning, in the world of technology, of the Age of Advanced Materials has led to a search for new ways of establishing research programmes capable of meeting the increased demand for materials. The State of New York, foreseeing the extent of the requirement for technological research in the 1990s, established the programme for Centers of Advanced Technology (CATs) primarily as a means of fostering economic development. Ten CATs and seven years later, New York's high technology research programme provides a model for workable partnerships between government, industry and academe.
Metallisation of Laser‐drilled Holes in 96% Alumina by Screen Printing Mixed‐bonded Pd/Ag: Printing Technology and Reliability of Metallisation
Authors: Giani E. , Kielar S. , Mathurin J.P.
Published: February 2008

Hybrid manufacturers are uncertain as to whether laser‐drilled holes on 96% alumina are suitable for mixed‐bonded thick film conductor metallisation, or whether they require further treatment before metallisation if reliable circuitry is to be produced. Moreover, although the metallisation of holes on ceramic through the use of screen printed thick films is fairly common in the hybrid industry, this paper shows that published information on this topic is scant, at times contradictory, and, because of proprietary constraints, generally of little use. The authors report on an extensive study in which both as‐laser‐drilled holes and thermally‐treated laser‐drilled holes are metallised using a mixed bonded Pd‐Ag conductor paste. Both encapsulated and non‐encapsulated metallised holes are then subjected to various accelerated life tests, followed by ‘power‐up’ tests to the extreme of circuit destruction. An account is also given of a printing set‐up which allows volume production of printed through‐holes without the need for special skill or attention on the part of the printing operator.
Characterisation of Thin Film Superconductors by Magnetically Modulated Resistance
Authors: Kim B.F. , Bohandy J. , Adrian F.J. , Phillips T.E. , Moorjani K.
Published: February 2008

It is of practical importance to measure and control the morphological state of thin film superconductors. Properties such as critical current, magnetic response and high frequency response are significantly affected by the microstructure of granular thin film specimens. A simple and functional method, magnetically modulated resistance, is described for assessing the granularity of superconductors.
3D Thermal Simulation of Power Hybrid Assemblies
Authors: Zardini C. , Rodes F. , Duchamp G. , Aucouturier J.‐L.
Published: February 2008

Among the main factors to be considered for the thermal optimisation of hybrid power modules are: the thermal resistance between the power chips and the bottom of the case; the thermal coupling between adjacent chips; and the ability of the module to withstand the thermal overloads induced by electrical surges. In this paper, the authors show how a finite element code can be used to optimise a hybrid power assembly in both steady‐and unsteady‐state. Comparisons made between results obtained with 3D and 2D simulations show that for hybrid power modules 2D simulations are generally unreliable. However, thermal studies cannot guarantee the reliability of hybrid power assemblies. Studies relative to hybrid power circuits must be thermomechanical.
An Evaluation of Polymer Coatings for Hybrid Circuits
Authors: Ročak D. , Kosec M. , Jan F.
Published: February 2008

An evaluation of some silicone and epoxy materials for primary chip and top coatings on hybrid circuits and of their relative merits on the basis of humidity and temperature cycling is presented.
Realisation of a Humidity Sensor Based on the Protonic Conductor Zn2Al(OH)6Cl.nH2O
Authors: Moneyron J.E. , de Roy A. , Besse J.P.
Published: February 2008

The electrical properties related to the hydration of the hydrotalcite‐type lamellar compound Zn2Al(OH)6Cl.nH2O are such as to permit the realisation of a humidity sensor. The sensor is achieved by depositing thick film by the screen‐printing technique. First, the means of forming the material is optimised. Two types of sensor are then realised, one working with direct current, the other with alternating current. The performance of each device is studied by means of specified experiments. The authors create a new measurement cell for calibrating the alternating current sensor. Response time measurements are carried out, and results are interpreted and compared.
Seminar on the Nordic PTF project
Authors: Kirby P.L.
Published: February 2008

This one‐day seminar, repeated in Sweden and Denmark, had its origins in a most interesting co‐operative project which was supported in the four Nordic countries by a total of eleven companies and research organisations. A series of six projects, each relating to a particular aspect of Polymer Thick Film Technology, was agreed by the participants, and the work programme was carried out mainly in national research institutes but with a considerable input from industrial collaborators.