Reducing Electrical Resistivity of Copper-CNT Composite Film for High-Ampacity Back End of Line and Interconnection

In recent years, sintered Ag and sintered Cu have been attracting attention as die-bonding materials for next-generation power semiconductors. It has been reported that Cu-CNT composites have better thermal and mechanical properties than Cu, and may be a die-bonding material that can withstand higher loads. However, the Cu-CNT composite has a problem of having a higher electrical resistivity than Cu. In this report, in order to reduce the electrical resistivity of the CuNP-CNT composite sintered film, N-methyl-2-pyrrolidone (NMP), which has high CNT dispersion properties, and ethylene glycol (EG), which has reducing properties, were adopted as the solvent for the CuNP-CNT paste, and the electrical resistivity was compared. The sintering temperature was set at five conditions ranging from 200-280°C, and when EG was used under this experimental environment, the electrical resistivity at the low temperature side (200-240°C) was lower than that of NMP. The effectiveness of EG as a solvent for the CuNP-CNT paste was demonstrated.