Fabrication of TiO2/Cu hybrid composite films with near zero TCR and high adhesive strength via aerosol deposition

Room-temperature fabrication of TiO2/Cu composite films for embedded passive components were attempted via aerosol deposition process. XRD analysis and observation of internal microstructures revealed that TiO2/Cu composite films using 500 nm-sized TiO2 had further tight bonding between particles compared to 25 nm-sized TiO2, due to effect of initial TiO2 particle size on densification of internal microstructures. Then, to optimize their adhesive strength and temperature coefficient of resistance (TCR), electrical and mechanical properties of TiO2 (500 nm)/Cu composite films with different content of TiO2 were evaluated for applications as advanced composite film resistors. Results showed that TiO2/Cu (50 wt%/50 wt%) composite films had sufficient electrical resistivity (5.8 ×10−3 Ω cm), excellent near-zero TCR (−3 ppm/℃), and improved adhesive strength (~ 7.37 N/mm2) resulting from proper coexistence of anchoring bonds and mechanical interlocking formed during deposition.