Anti-oxidation copper powder with constructed calcium silicate hydrate nano-barrier layer for printable electrode paste

Copper-containing electronic pastes, known for their low cost and low electrochemical migration, have been extensively investigated for use in conductive electrodes for low-temperature co-fired ceramic (LTCC) technology. However, the oxidation susceptibility of copper makes circuits prone to oxidation, leading to increased device resistance and reduced reliability. Core-shell structured copper particles with uniform nano calcium silicate hydrate shell layers (Cu@CSH) were prepared by hydrothermal treatment of sol-gel coated copper powders to enhance the anti-oxidation properties of the particles. Specifically, the Cu@CSH particles, synthesized with varying coating layer contents, significantly influenced the sintering behavior and substrate adhesion of the copper pastes. The Cu@CSH-based copper pastes were screen-printed onto LTCC substrates and demonstrated low sheet resistance (22.45 mΩ/sq) and strong adhesion (50.40 MPa) after undergoing debinding in air followed by sintering in an N 2 atmosphere. This study provides a novel method for preparing core-shell structured copper powders for electronic applications.