Synthesis and characterization of sub-micron sized copper-ruthenium- tantalum composites for interconnection application

Sub-micron sized ruthenium and tantalum reinforced copper composites as suitable material for electronic interconnection applications was synthesized using high temperature high pressure technique. High purity sub-micron starting powders were blended in a turbula mixer at varying compositions and consolidated at temperature of 850°C and pressure of 30 MPa for 30 min. The density, phase composition, microstructure, hardness and electrical conductivity of the resulting materials were investigated. The addition of 2.5 vol% ruthenium improved the density of the pure sintered Cu from 97.20% of the theoretical to 99.89% and increased the Vickers hardness value from 114.2 HV to 127.8 HV. Tantalum addition was found to inhibit copper grain growth during sintering. The electrical resistivity of copper based composites remained relatively low with the addition of reinforcement materials.