Analysis and Sintering Optimization of Nanoparticle Paste with High Silver Content

This paper deals with analysis, testing, and process optimization of new nanoparticle silvering paste with high silver content. Specifically, on ceramic substrates with printed conductive patterns created by thick film technology. Sintering is currently one of the most anticipated ways of connecting dies on substrates in power electronics field. Using ceramic substrates in combination with printed patterns brings out new challenges because of porous structure and ceramic specific attributes, especially when using presureless sintering as in this case. Presented paper is focused on analysis and comparison of structure and behaviour of the new nanoparticle paste with commercially available silver sintering pastes. Following step was initial testing with different deposition techniques and development of optimal sintering profile. After sintering examinations were also carried out. Shear test showing mechanical resilience, x-ray scanning for analysis of internal structure and stereoscopic analysis of sintered paste. Prolonging the temperature peak from 45 to 60 minutes and rising its temperature to 280°C shows better results in created joint. Higher shear strength was achieved together with more homogenous sintered structure. Lower porosity and presence of nanoparticles shows great potential for more homogenous, stable, and more resistive connection to mechanical separation.