A novel silver–aluminium high-temperature die attach nanopaste system: the effects of organic additives content on post-sintered attributes

An Ag–Al die attach material having a fixed Ag–Al nanoparticles weight percent content (80–20 %), as well as varying organic additives weight percent content was formulated. The total nanoparticle weight percent content was varied between 84.7 and 87.0 %. As the organic additives content in the Ag₈₀–Al₂₀ die attach material decreased from 15.3 to 13.0 %, the nanopaste’s viscosity increased. The die attach material was sintered at 380 °C for 30 min to form Ag₂Al and Ag₃Al compounds. With decreasing organics content from 15.3 to 13.0 %, the porosity of the post-sintered samples also decreased from 30 to 19 %, while the density increased from 2.36 to 6.42 g/cm³. The highest melting point was recorded for the sample with the least organic weight percent content at 519 °C. The coefficient of thermal expansion and electrical conductivity values varied between 6.99–7.74 × 10⁻⁶/ °C and 0.95–1.01 × 10⁵ (ohm-cm)⁻¹ respectively with decreasing organic content from 15.3 to 13.0 %. The electrical conductivity values recorded were higher than or equal to that of most solder alloy die attach materials. By changing the organic additives content in the Ag₈₀–Al₂₀ die attach material, suitable properties are obtained for high temperature die attach applications.