Thermochemically-Driven Reactions at Metal/Ceramic and Ceramic/Ceramic Interfaces in Multilayered Electronic Materials

摘要

The use of ceramic materials in electronics has expanded dramatically over the last decade, and this trend is expected to continue. Ceramics find many applications because of their dielectric characteristics, especially in microwave devices, where properties can be tuned by controlling chemistry. While comprising a diverse group of materials, electronic ceramics in multilayer structures have in common the need for sintering at elevated temperatures (800 deg C and above) in order to achieve the desired structural integrity. At these temperatures, chemical reactions may occur at interfaces between dissimilar materials. Three principal types of interactions involve combinations of the metallization, the embedded passive ceramic devices, and the ceramic packaging material. To model the metal/passive interaction, we use as an example the system CuO-x-Bi-2O-3-Nb-2O-5. Similarly, the system BaO-SiO-2-TiO-2 allows us to treat an example of passive/packaging interaction. Finally, an example of metal/packaging interaction is found in the system CuO-x-CaO-SiO-2. By combining phase equilibrium data with thermodynamic properties, it is possible to develop models for interfacial interaction within each of these systems. Of special importance is the generation of chemical potential diagrams, which allow interpretation and prediction of interfacial reaction sequences. By fabricating bi-phasic interfaces and annealing, it is possible to follow experimentally the evolution of interfacial reaction zones. Such data can then be used in iterative fashion for model development. The current status of the development of ceramic interfacial reaction models will be discussed.