The paper presents a digest of chosen research and technical work results shown by researchers from technical
universities, governmental institutes and research firms during the XIth Scientific Conference on Electron Technology
ELTE 2013. ELTE Conference has been held every three years since more than three decades. The ELTE 2013
conference was held in Ryn Castle (Poland) on 16-20 April 2013 and gathered around 270 scientists, theoreticians,
technologists and engineers from such areas as material engineering, chemistry, sensors, integrated circuits, electronics
engineering, laser industry, photonics, etc. The conference featured the following major four topical sessions – Micro
and Nano, Photonics, Materials and Technologies, and Microsystems; two dedicated sessions – a keynote plenary
session on hot topics in electron technology, as well as a session on large research projects and grants realized by the
relevant community. Oral topical sessions were accompanied by poster sessions. The paper is a succinct topical
introduction to the volume of ELTE 2013 proceedings. Over 100 papers, gathered in the volume, present a very
relevant cross section and state-of-the-art of this branch of science and technology in Poland with involved international
The aim of our paper is to consider the possibility of applying pure Ag technology for assembly of SiC Schottky diode
into a ceramic package able to work at temperatures up to 350°C. Ag micropowder was used for assembly SiC structure
to DBC interposer of the ceramic package. Ag wire bonds as well as flip-chip technology using Ag balls were used as
material for interconnection systems. The parameters of I-V characteristics were used as a quality factor to determine the
Schottky diode after hermetization into ceramic package as well as after ageing in air at 350°C in comparison with
characteristics of bare SiC diode.
It is becoming more and more difficult for the conventional PCBs with mechanically drilled vias and plated through holes to meet the current packaging density requirements. To overcome these challenges, new manufacturing schemes for high density and high performance multilayer PCBs have been developed. The polymer materials play important role in finding the cheap solution. Polymer materials are used to make reliable vertical interconnects in substrates made by SBU (Sequential build-up) processes. The SBU technology with conductive paste filled microvias can achieve a connection density of up to 100 pads/cm<sup>2</sup> while the conventional PTHs can reach only 20 pads/cm<sup>2</sup>. The polymer base materials can be used to replace solders in PCB assembly. The exploitation data obtained from own research, and connected with applying adhesives in inner connections into PCB as well as connected with component assembly on PCB were given.
The electromigration on printed circuit test boards after soldering process was under investigation. FR-4 laminate, that is the most popular laminate for printed circuit boards fabrication, with 35mm thick copper layer was used in the test. Six various solders were applied in this work, which differed with silver content from each other. Some solder contained lead and copper. For electromigration assessment two tests were performed: Surface Insulation Resistance Test and Water-Drop Test. Silver presence in the solder do not decreased insulation resistance of test printed circuit boards. This implies, that small silver content in a solder does not increase electromigration of solder material. The "Water drop" test showed, that silver addition decreases electrochemical migration in continuous water layer on printed circuit board surface.
The electronic industry is engaged in developing Pb-free technologies for more than ten years. However till now not all properties of new solders are described. The aim of the paper is to present some electrical properties of new series of Pb-free solders (eutectic SnAg, near eutectic SnAgCu with and without Bi) in low temperature ranges 10 K to 273K. The following parameters were analyzed: electrical resistivity, temperature coefficient of resistance and thermoelectric power. The electrical resistivity at temperatures above 50 K is a monotonically rising function of temperature for Pb-free solders studied. The electrical resistivity of the Bi containing alloys is higher as compared to the remaining ones. The thermoelectric power values at room temperature are about -8 μV/K to -6 μV/K for Pb-free solders studied, being higher as compared to typical values -3 μVK of SnPb solder. The relatively low absolute values as well as the smooth and weak temperature variation of electrical resistivity in lead free solders enable the possible low temperature application. The moderate values of thermoelectric power around and above the room temperature show that when applying the solders studied the temperature should be kept as uniform as possible, in order to avoid spurious or noise voltages.
There is an increasing demand in replacing SnPb solders with Pb-free solders in the electronic industry due to health and environmental concern. The European Union passed a law to ban the use of lead in electronics on February 13, 2003. The ban goes into effect on July 2006. The aim of the paper is to overview the necessary changes in materials and technologies for "green" electronics products. The materials and assembly technology changes on first-level package as well as on second-level package will be presented. Detailed analyse of some Pb-free solders as well as Pb-free component and PCBs finishes properties will be done. Some experimental data comparing Pb-free and SnPb solder joint properties are summarized. Finally the paper gives perspectives of transitions to a totally Pb-free manufacturing.
The electronic industry is now going through a difficult period. The companies must cut costs, regroup and innovate. Environmentally friendly production from cradle-to-grave can be an essential element of future manufacturing trends. Recognizing leaf-free technology implementation it is necessary to consider the following elements: solder, printed circuit board and component finish or assembly technology. In the paper, the [hysical properties of chosen Pb-free solders were presented. There were analyzed the advantages and disadvantages of two PCB assembly methods: lead free soldering and gluing by condictive adhesive. The comparison of electrical and mechanical properties of joints made by Pb-free solders and two types of conductive adhesives were presented too. It was concluded that the exploitation parameters of joints made by Pb-free solders are proper for PCB assembly. Conductive adhesives may replace solders in these applications were the low value of joint resistance is not critical.