Electrical, Microstructure and Rheology Properties of the Low-Curing-Temperature Silver Paste with Different Carbon-Chain Type Metallo-Organic Salt Wetting Coating

摘要

In this paper, the low temperature curing and high conductivity behaviors of silver films using silver paste with metallo-orgainc salt C_nH_(2n+1)COOAg compound additions are investigated. The low curing temperature silver paste made from flake silver powder, solvent terpineol and various carbon-chain types of metallo-organic decomposition (MOD) compounds wetting coating on flake silver powder, were prepared and characterized. The microstructures and resistivities of cured films screen-printed from the pastes were examined. The printable and paste rheology were detected using dynamic rheometer. The metallo-organic silver salt decomposition left almost pure and nano silver particles on the flake silver powder surface, which is beneficial for bridging between silver flake powder in the films. The carbon-chain length of metallo-organic silver salt were influenced the decomposition temperature, viscosity and rheology behavior of paste and dissolving behavior by molecule polarity.rnThe different carbon-chain length metallo-organic silver salts were synthesized from organic acid with AgNO_3. The metallo-organic silver salt of synthesized were identified by FITR. Thermal decomposition effects of different carbon-chain metallo-orgainc silver salt compounds decomposition behavior are evidenced by TGA and the decomposition activation energy E_a calculated analysis. The microstructures of screen-printed films on alumina substrate after thermally treated were characterized and discussed by field-emission scanning electron microscope (SEM). The electrical resistivity properties of the films were measured using four-point probe method at the curing temperature of 200° to 250℃. The results indicate that metallo-organic silver salt compound C_nH_(2n+1)COOAg carbon-chain (n value) must more than 4 were obtained the excellence electrical resistivities, microstructure and rheology characterization.