The invention provides a micro-nano mixed
welding paste capable of being used for
pressureless sintering preparation and a packaging method thereof. The interior of a material is filled with micron-sized spherical particles as a matrix, and the nano-particles are uniformly filled in the material,
sintering driving force is provided, so that the whole material is subjected to pressureless sinteringforming at a low temperature. The preparation method comprises the following steps of S1, preparing micron particles with specific sizes and carrying out
acid washing and
drying; S2, mechanically stirring the micron particle
powder with a surfactant, an organic carrier and an
organic solvent to obtain a mixture A; S3, fully mixing the
metal nano-particles with a dispersing agent, the organic carrier and the
organic solvent to obtain a mixture B; and S4, mixing the mixture A and the mixture B to obtain the micro-nano mixed
welding paste. According to the micro-nano mixed
welding paste capableof being used for
pressureless sintering and the preparation method thereof, the welding paste solves problems of volume shrinkage and cracks of the nano welding paste during
sintering, the reliability of the welding spots is improved, and the welding paste can be used for packaging and manufacturing for power devices; and according to the scheme, the production process of the welding paste is simplified, the preparation process is green and environment-friendly, the packaging method provided is simple and practical and is beneficial to market popularization.