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Silver processing in thick film technology for power electronics

: Eberstein, M.; Feller, C.; Seuthe, T.; Ihle, M.; Ziesche, S.; Gora, F.

Postprint urn:nbn:de:0011-n-2114542 (2.3 MByte PDF)
MD5 Fingerprint: 0eaedd7e1db332ad3b105ccfd6b32100
Created on: 31.10.2012

Müller, Jens ; International Microelectronics and Packaging Society -IMAPS-; American Ceramic Society -ACerS-, Westerville/Ohio:
IMAPS/ACerS 8th International Conference and Exhibition on Ceramic Interconnect and Ceramic Microsystems Technologies, CICMT 2012. Proceedings : April 16-19, 2012, Erfurt, Germany
Erfurt, 2012
International Conference and Exhibition on Ceramic Interconnect and Ceramic Microsystems Technologies (CICMT) <8, 2012, Erfurt>
Conference Paper, Electronic Publication
Fraunhofer IKTS ()
silver powder; silver paste; diffusion; sintering; LTCC; power electronics

Processing of Ag-equipped thick film modules is still challenging due to well-known issues of warpage of Ag-containing LTCC substrates or undesired coloring of Ag-surrounding ceramics. To increase the workability of Ag based thick film modules, enhanced control over these effects is necessary. From the experimental background as well as the chemical and thermodynamic nature of the element Ag, conclusions regarding essential properties during Ag-high temperature processing, like initial oxidation, transport via the vapor and glassy phase, and reduction are discussed. Taking into consideration a possible occurrences of this phenomenas as activated/deactivated dependent on sintering conditions, explanation of unwanted manufacturing results like LTCC staining, warpage, glass thinning and sette r memory effects are possible. From a technical standpoint, there are roughly two temperature ranges of relevance for processing silver metalized thick film structures. Between approximately 300 °C and 700 °C fast transport mechanisms of silver through the gaseous phase take place. Control can be achieved via governing the silver manufacturing oxygen partial pressure, organic composition, powder conditioning and temperature-time schedule. Above approximately 600 °C, slower transport mechanisms of silver through the glassy phase and possible reduction of Ag(I) become evident. These effects originate corresponding impacts on the sintering kinetics. Here, control can be achieved via governing the glass composition, redox potential and, again, temperature-time schedule.