Mixed conductive silver paste for package of nano chip

Abstract

The invention provides a mixed conductive silver paste for package of a nano chip. The preparation method is simple, stable and reliable in preparation process and free of pollution to the environment. The mixed conductive silver paste comprises the components: 65-85% of aluminium powder, 5-25% of an organic solvent, 1-2% of a dispersing agent, 10-20% of an organic carrier, 0.5-5% of surface active agent, and 0.1-5% of a diluent. An abietic acid is taken as the surface active agent, and the mixture of the acrylic resin and the ethyecellulose is taken as the organic carrier to effectively delaythe generation of mass diffusion and avoid generation of low-temperature non-intensive diffusion, the mixing of the nano silver powder and the micron silver powder is employed to maintain the stabilization of particles and have the effects on dispersion of nano particles and avoiding of agglomeration so as to improve the performances of the slurry; the sodium and silver slurry obtained by employing the formula and the preparation method has the thermal conductivity being 193W / (K.m) after sintering which is better than the thermal conductivity of the thermal conductive glue and the alloy solder for package, and the shear strength of a sintered joint can reach 37.5 MPa, and the performance is excellent.

Description

technical field [0001] The invention relates to the technical field of chip packaging, in particular to a mixed conductive silver paste for nano chip packaging. Background technique [0002] Due to worldwide restrictions on the use of lead-containing solder in electronic packaging and interconnection, electronic lead-free has always been the focus of electronic interconnection research. At present, the main lead-free solders are Sn-Ag-Cu, Sn-Cu and Au- Alloys such as Sn, but compared with Pb-Sn solder, lead-free solder still has disadvantages such as poor processing performance and high processing temperature. On the other hand, the widespread use of high-power wide-bandgap chips and the sharp increase in power density make the packaging system have higher and higher requirements for heat dissipation, and the thermal conductivity of mutual thermal paste and alloy solder used for chip-level interconnection is becoming less and less capable fulfil requirements. Nano-intercon...

AI Technical Summary

Problems solved by technology

However, silver nanoparticles are often in an unstable state in thermodynamics, leading to agglomeration between particles, which will lead to uneven dispersion of silver nanoparticles, thus forming large holes, which significantly reduce the original powder density before sintering, and the effective radius ratio The actual radius is much larger. When the effective radius reaches the micron level, the advantages of nano-silver particles are gone.