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In the light of continuous miniaturization of traditional microelectronic components, the demand for decreasing wire diameters becomes immediately evident. The observation of metallic conductor properties for certain configurations of carbon nanotubes (CNT) and their current carrying capability [1] set the minimal diameter of a true wire to about 3 nm (compare Chap. 15). Investigations are in progress even below that diameter on nanocontacts, formed by single metal atoms, i.e., quantum wires. Quantum wires can be produced by mechanical wire breaking [2], its combination with etching and deposition [3], or other techniques. The properties of quantum wires are only about to be understood theoretically [4]. Doubtless, they are worth considering for packaging solutions in molecular electronics to come [5]. In this chapter, we focus on metal wires and rods in the size range above 10 nm up to submicron diameters, evaluated already to be attractive for microelectronic packaging purposes. Techniques to generate, to characterize, and to handle them, as well as their interaction with electromagnetic fields will be useful for packaging applications in the age of nanotechnology. With the wealth of information available, this review focuses on general trends and starting points for deeper study. Although the cited references are representative, they cannot be complete, since numerous activities are ongoing to produce and to characterize new kinds of wire-like geometries from different materials.

The electronics industry has successfully transitioned to lead free soldering for computer and consumer products while in the automotive industry due to the very high reliability requirements this step is still in an ongoing process. In order to ensure or even to enhance the reliability of electronics the improvement of lead free solder joints based on Sn-Ag-Cu (SAC) solder has been the focus of many research projects already. One approach to improve the thermal fatigue properties of these alloys is to add a further alloying element SAC + X. Until now, further elements have mainly been added by metallurgical alloying, requiring special equipment and conditions. The powder production is even more difficult. In this paper a new way how to add minor amounts around 0.1 wt.-% of a forth element to SAC solder joints is presented. One possibility is to do the doping during the reflow process adding the additional elements via the flux by incorporating Co-, Fe-, Al- or other metal compounds into the flux. Experiments have shown that Co and Fe were successfully added while for certain other elements like for example Al this was not possible until now. In comparison to standard SAC solder the Co containing solder shows a refined microstructure and Co is found in the intermetallic phase Cu 6 Sn 5 . Fe which has been found at grain boundaries is not only attractive as alloying element but as metallization layer, too. It is possible to deposit Fe on printed circuit boards using electroplating. During soldering the slowly growing FeSn 2 phase forms between the solder and the Fe layer.

A selective and also simultaneous reflow soldering process is possible in principle by using of electromagnetic fields, if the field energy is penetrating the processed assembly and is able to launch into specific material regions, depending on material properties (Nowottnick, 2005). The application of electromagnetic radiation in the microwave range enables the treatments of products with different sizes and shapes, also with an open inline system with a high throughput. But common solder pastes are demanding a lot of time and a high power density for heating with microwave. By adding a defined amount of a special well launching material to the solder paste, the so called suszeptor, it is possible to increase the efficiency of microwave heating considerably. Such suszeptors must have adequate polar or dielectric properties and have to be mixed to the soldering flux as a solid or liquid. By means of this mixture is it possible to fasten the heating of solder paste in comparison with the remaining assembly, which is necessary for minimizing of used microwave energy

New applications of template-generated structures and surfaces are foreseen in microelectronic joining, photonics, and analytical chemistry. They require a special tuning of morphological and topological parameters. High-resolution imaging techniques allow for optimising surface properties and grain size of metal-rod decorated surfaces. Submicron wires and more complex "lawn"-structures with diameters of 600 ? 50 nm have been produced by galvanic deposition at porous polymer templates. Their application for low-temperature interconnect formation is under evaluation. First results indicate that single-metal and layered "nano-lawn" can be attractive for microsystem technology in general, but also in analytical chemistry and related fields. Template techniques are discussed and experimental approaches to use gold nano-lawn are presented. The development of new materials and appropriate techniques will be useful for future packaging technologies of (micro-)electronics to come.

Besides the common fiber technologies like splicing, polishing and coating there is a demand for specific methods for advanced packaging solutions in the field of telecom and medical applications. We present here three of such methods for lensing glass fibers that can be used to increase optical performance and reliability as well as to reduce the packaging efforts. These technologies are very useful for micro optical assembly, i.e. fiber connectors for high power applications, collimators and telecom transceivers and endoscope imaging or sensor systems. At the Fraunhofer Institute for Reliability and Microintegration Berlin special photonic packaging solutions are developed. Optical interconnects have been obtained a great importance for optical data transfer. Optical fibers are necessary for disturbance free communication of high data rates via long distances. Optical system components perform generation, distribution, transformation, amplifying and processing of optical signals. That's why optical systems are a assembly of different kinds of functional basic elements such as optical fibers, splitters, switches, modulators, transmitters and detectors. Furthermore, industrial applications need a reliable and cost effective coupling of optical fibers to those systems.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.