Ivan Szendiuch

Optimization of Properties of Planar Spiral Inductors

This paper deals with investigation of properties of planar spiral inductors realized by application of thick film process. Various implementations of the thick-film planar spiral inductors can be considered. Various film processes were used for fabrication such as screen printing, direct writing and ultrasonic wire bonding and its combinations. Some of projected patterns of the inductors were fabricated and its electrical properties were measured. The results are discussed. Generally, the background of this work was to find out the optimal thick film technique and structure of thick film planar inductor, which can be applicable to construct the thick film transformer. The considered transformer could replace the PCB solutions, in some applications.

Effect of nitrogen atmosphere on the soldering process for different types of lead-free solders

An important part of the microelectronics manufacturing is the reflow process. Even though that the soldering have a long history, the process is still not completely described. Particular still discussed the introduction of the WEEE Directive 2003/108/EC standards and RoHS Directive 2002/95/EC got the soldering received into new areas. There is a space for new material compositions which do not contain lead. Furthermore, a new procedure process, adjusting of equipment and began to make greater use of nitrogen as protective gas. The aim is to compare the already proven commercial solder alloys on different carrier and evaluate more exactly the benefits of nitrogen atmosphere. The evaluation was performed for solder SAC, Sn100C and SnPb solder paste was used as reference. Type of substrates was printed circuit board FR-4 and ceramic substrate. Soldering conducted in atmosphere with different residual oxygen. Results of this paper may serve to increase the quality of soldering classical package as well as BGA and CSP package.

Finite element modeling of surface mount devices

The aim of this paper is to improve reliability of SMD connecting and to increase durability of these structures. 3D finite element analysis has been applied to determine the time-dependent solder joint fatigue response and under accelerated temperature cycling conditions (-40C to +125C, 15min ramps/15min dwells). And definition place with maximal stress value rising in solder joint under shearing. This paper describes recent developments made to the finite element modeling of SMD, extending its capability to handle viscoplastic behaviour. It also presents the validation of this approach and results obtained for an SMD. Lifetime predictions are made using the creep strain energy based models of Darveaux. This study discusses the analysis methodologies as implemented in the ANSYS finite element simulation software tool

Usage of LTCC technology in electronic packaging

Low Temperature Co-fired Ceramics (LTCC) is very progressive technology, which finds utilization in a couple of applications deal with new microelectronic structures and configurations. Contributing application is also electronic package, where LTCC offers many possibilities, such as realization of 3D structures, embedded components, etc. In this paper the main aim is focused on usage of this technology for design and development of new electronics package, which should be cheap and easy for manufacturing. Such type of package will be very useful either for research laboratories and test vehicles or for simple electronic circuits, which needs to be attached to the electronics system through the package.

Reliability and Simulation of Lead-Free Solder Joint Behavior in 3D Packaging Structure

This paper deals with behavior of lead-free solder joint applied in 3D electronic packaging structure. There are plenty of factors which influences reliability and life-time of solder compound connection. Type of substrates, selection of materials and process arrangement are the main areas to investigate. The content consists from three main parts. The first deals with introduction of designed test pattern, material, and process arrangement and applied testing methods. Second part continues with ANSYS software simulation of solder interconnections during thermo-mechanical stress tests and third part is aimed to experimental evaluation of results in the comparison to simulated results.

Performance of laser machined and metallized via holes in LTCC tape materials

This paper deals with analyses of laser-machined via interconnections in LTCC (Low Temperature Co-fired Ceramics) substrates with regard to geometrical performance of holes and electrical characteristics of metallized via holes. Tapes and compatible via filler pastes from different suppliers have been tested. In order to realize via interconnections with different diameters the optimal laser parameters have been determined experimentally for each selected tape. The smallest possible holes manufacturable with an optimized reliable laser machining process were determined experimentally for each tested tape material. The results of optimized via hole configurations are shown in the green state. Accordingly, qualification criteria are indicated. Electrical measurements have been carried out in order to determine the electrical resistance of metallized via interconnection depending on via diameter.

Reference electrodes for thick-film sensors

Paper deals with a problematic of thick-film electrochemical sensors for trace analysis of species or elements in aqueous solutions. A problem of replacement of classical Ag/AgCl reference electrodes by planar thick-film electrodes is discussed here. In this paper there were compared several thick-film reference electrodes with classical ones using the same electrochemical arrangement. Special commercial thick-film pastes and electrochemically fabricated Ag/AgCl layers were used for reference electrodes of thick-film electrochemical sensors and characterized in standard electrochemical solution of potassium ferro-ferricyanide. First results show big difference between tested materials, mainly in shifts of half weave potentials. Moreover with use of screen-printed reference electrodes, there was shown a high output current dependence on the change of electrodes distances.

Wire bonding power interconnection

This paper describes recent developments in the finite element modeling of wire bonding interconnection, extending its capability to handle viscoplastic behavior. In this project a test system to be used in investigation and research on reliability of interconnections in integrated circuits and printed circuit boards will be developed and realized. Especially the reliability of interconnections of semiconductor chips under high current regime until 10 A, or more, is emphasized. The aim of this paper is to improve the reliability of semiconductor chip power interconnection and to increase the durability of these structures. The first objective is to determine stress distribution in connection wires. Wire cracks may occur in places of maximal stress. Another objective is to investigate current distribution in wires. The theoretical results will be completed with data from real experiments.

Some remarks to the effectiveness of the cleaning in electronics production process

This paper deals with research of the cleaning methods efficiency measurement in the sector of electronics assembly technologies. The cleaning is a necessary technological step whose importance is increasing with the development towards smaller resolution. Increased miniaturization, higher speeds and tighter board space highlights that need, as well as request for a higher reliability in some types of applications (automotive, medical, military etc.). Moreover, with introduction of new environmental regulations (WEEE, RoHS) and eco-design (EuP) rules the cleaning becomes to be more and more in the centre of attention. The cleaning process is important for various parts of technological processes, including lead-free solders process. Any various contaminants such as ionic or non-ionic flux residues, etching residues, handling contamination, fingerprints etc. can cause a decrease of lifetime could reduce lifetime and cause fatal failures. Therefore cleanliness is only the only way how to achieve acceptable reliability of electronic circuits and assemblies. But there is not enough information on which method to choose and how to arrange parameters. Described in this paper is the new method for measurement of cleaning efficiency by optical valuation, and some obtained results are discussed.

Thick film double thermodynamic sensor system

This paper deals with a new family of thick film sensors used for thermodynamic monitoring and controlling of processes in industrial systems. In previous papers mentioned below the below mentioned basic principle of new thermodynamic sensor was introduced and its construction on alumina ceramic substrate was demonstrated. Generally, this sensor has plenty of application possibilities in various areas of industry sectors. Some final users especially from the RF area call for sensors that are independent from of contiguous environment effects. Such applications can be realized by using the double thermodynamic sensor probe. The basic principle of this solution is an external thermodynamic sensor that creates the thermodynamic environment shield for the internal sensor used for process monitoring inside the shielded area. Before implementation of the sensor system the simulation model of the double thermodynamic sensor as a particular element of the thermodynamic system was calculated. The values obtained from simulation (ANSYS, FLOMERICS) are compared and valuated with experimental results, and are shown in this paper. There is a good conformity between calculated and measured values. Results obtained from simulation enable construction of are used to construct a new family of double thermodynamic sensor probes in thermodynamic circuitry models, which are integrable in many industrial thermodynamic systems designed in standardized design environments (ANSYS, MATHCAD, FEMLAB etc.). They can be used as technical solutions in process and media monitoring for the controlling system integral design of any complex thermodynamics systems, namely automotive, power, heat distribution, food, chemical and petrochemical industry etc.