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Bindlach, Germany

Brunner D.G.,ANCeram GmbH and Co. KG
CFI Ceramic Forum International

For many years now, various types of ceramics such as alumina, beryllia, steatite, cordierite, electrical porcelain, glass ceramics (green tape) have been used as insulators and lead holders in electrical engineering. Multilayer engineering is known from alumina, beryllia and green tapes. Especially for high power losses, the non-oxide ceramics aluminium nitride and silicon nitride are increasingly used or considered. With reference to several examples from the field, this report briefly outlines the state of the art in various applications and presents an overview of the new technologies for which material developments are underway or considered necessary. Source

Ponicke A.,Fraunhofer Institute for Ceramic Technologies and Systems | Schilm J.,ANCeram GmbH and Co. KG | Triebert A.,ANCeram GmbH and Co. KG | Sempf K.,ANCeram GmbH and Co. KG | And 4 more authors.
Keramische Zeitschrift

Copper-AlN- and copper-Si3N4-composites are used as substrates for semiconductor modules in power electronics. Silver-based active brazing alloys are used for the fabrication of composites from copper foils and nitride ceramics. In this study the mechanisms during active metal brazing (AMB) of aluminium nitride and silicon nitride in combination with copper foils were investigated. Therefore the melting process of the braze filler metal, the chemical interactions between the braze filler metal and the raw materials and the influence of the processing parameters were studied in detail using thermo analytic and microscopic methods. Additionally, the fabrication process was tested under close to production conditions and application like samples were fabricated. The combination of lab experiments with low volume productions in industrial relevant processing equipment ensures the transferability of the developed processing models from lab into production. An increase of the AMB process reliability and an associated quality improvement as well as a significant reduction of the rejection rate during fabrication was achieved by optimisation of the active brazing alloys and the processing conditions during the active metal brazing. Source

Brunner D.G.,ANCeram GmbH and Co. KG | Bohm G.,ANCeram GmbH and Co. KG | Raether F.,Fraunhofer Institute for Silicate Research | Klimera A.,Saint - Gobain
Ceramic Transactions

Debindering of Non Oxide Ceramics (NOC) like Si3N4, MoSi2 or AlN has been investigated using a kinetic model to understand and optimize binder removal in Ar or N2 atmosphere. The paper focuses on AlN ceramics, especially high volume parts for applications in semiconductor industry, power electronics and space applications. Properties of AlN green parts have been monitored during debindering: wetting behavior of binder, permeability of gaseous species in pore channels, debindering kinetics and mechanical strength. The maximum safe debindering rate was determined allowing debindering without any damage of specimen. A kinetic model was used to calculate optimized heating cycles from the experimental data. Results are shown for an AlN unit dedicated for space application. Source

Bohm G.,ANCeram GmbH and Co. KG | Brunner D.,ANCeram GmbH and Co. KG | Sichert I.,ANCeram GmbH and Co. KG | Ponicke A.,Fraunhofer Institute for Ceramic Technologies and Systems | Schilm J.,Fraunhofer Institute for Ceramic Technologies and Systems
44th International Symposium on Microelectronics 2011, IMAPS 2011

This paper focuses on the properties of Si3N 4substrate material with AMB (active metal brazing) copper conductor. A recently developed type of tape casted, gas pressure sintered silicon nitride ceramic with a three times higher thermal conductivity than known from typical standard silicon nitride materials and with good flexural strength was applied. The increase of thermal conductivity is the result of using different species of sintering aids and the optimization of their ratio in the material. The high bending strength allows creating a thinner substrate compared to other standard ceramic materials for power electronics, e.g. aluminum nitride. This reduction in thickness leads to a decrease of the total thermal resistance of the substrate which improves heat dissipation. For the AMB process a silver based active brazing solder composition optimized for Silicon Nitride was used. This optimization could be obtained by an investigation of the physical and chemical interactions between the brazing and the base material. A void free joint without short circuits between adjacent structures could be formed. The copper surface can be coated on demand with Nickel or Nickel/Gold for improved solderability and wire bondability as well as for corrosion protection. The silicon nitride substrate with AMB copper conductor lines and fully covered back side ground shows a higher reliability than comparable substrates made out of common, well known ceramic materials. The heat dissipation is comparable with conventional AMB substrates made of high thermal conductive ceramic such as Aluminum Nitride, but thermal cycling behavior exceeds the limits well known from AlN-AMB or AlN-DCB. Source

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