Study of New Nitrogen-Fireable Copper-Nickel Thick Film Paste Formulation Compatible with Thick Printed Copper

This paper is focused on a new copper-nickel thick film resistive paste which was designed and experimentally developed for the realization of low-ohmic power resistors. This copper-nickel paste has been designed for use in combination with thick printed copper conductors and in comparison with conventional ruthenium-based thick film resistor pastes allows firing in a nitrogen protective atmosphere. The copper-nickel paste was prepared from copper and nickel microparticles, glass binder particles and a combination of organic solvents optimized for its firing in a nitrogen atmosphere. This paper covers a detailed description of copper-nickel paste composition and its thermal properties verified by simultaneous thermal analysis, a description of the morphology of dried and fired copper-nickel films, as well as the electrical parameters of the final printed resistors. It has been proven by electron microscopy with element distribution analysis that copper and nickel microparticles diffused together during firing and created homogenous copper-nickel alloy film. This film shows a low temperature coefficient of resistance +/- 45 x 0(-6) K-1 and low sheet resistance value 45 m omega/square. It was verified that formulated copper-nickel paste is nitrogen-fireable and well-compatible with thick printed copper pastes. This combination allows the realization of power substrates with directly integrated low-ohmic resistors.

Automated summary

This paper introduces a new copper-nickel thick film resistive paste designed for low-ohmic power resistors. The paste allows firing in a nitrogen protective atmosphere, in contrast to conventional ruthenium-based pastes. The paper provides a detailed description of the paste composition, thermal properties, and electrical parameters, as well as verification of its compatibility with thick printed copper pastes.