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A. Aghzout, J. Nicolics:
"Investigation of the Electric Resistance of Anisotropic Adhesive Bondings for Power Electronic Applications";
Vortrag: International Spring Seminar on Electronics Technology (ISSE), Neusiedl am See, Austria; 04.05.1998 - 07.05.1998; in: "Proceedings of 21st International Spring Seminar on Electronics Technology (ISSE 98)", Werkstoffe der Elektrotechnik, Wien (1998), ISBN: 3-85465-004-3; S. 146 - 150.

Anisotropic electrically conductive adhesives (Z-axis adhesives) are increasingly employed in microelectronics, particularly in areas of small-pitch applications. In contrast to soldering, this interconnection technique is usually lead free and allows to omit cleaning. Moreover, the use of anisotropically conductive adhesives (ACAs) offers numerous advantages such as low processing temperature, short impact of heat, reduced device thickness, and low cost. ACAs are composed of a polymer matrix and a conductive filler material. The latter can be flakes or spherical particles of Ag, Au, Cu, Ni, or metal-coated polymer particles. In any case, the particles and their contact to the mating metallizations are responsible for the electrical transition resistance of an interconnection.
In this paper, for the first time, this resistance is analyzed theoretically by means of a simple model which considers the number of particles, their resistance, the specific conductivity and the geometry of the contact tracks. The study shows that the minimum resistance is obtained only at a distinct particle number. Furthermore, the influence of aging processes like formation of oxides in the contact area and their impact on the transition resistance is discussed. Some results of this theoretical study are compared with those obtained from experiments.