| As chip interconnect material,conductive adhesive has the advantages of low bonding temperature,high line resolution,simple operation process and environmental friendliness.However,poor electrical conductivity,mismatched thermal expansion coefficient and high price were inevitable.The SiO2@Ag were synthesized and used as the conductive filler of the conductive adhesive and studied effects of SiO2@Ag on the conductive properties.Finally,the conductive adhesive with extremely low thermal expansion coefficient and excellent electrical and mechanical properties was prepared.A layer of nano-silver particles with uniform diameter and dense coating were plateed on the spherical silica surface by Electroless plating.A variety of analytical instruments were used to characterize the morphology,structure and low-temperature sintering performance of SiO2@Ag composite particles.The results show that the surface of silica was covered with uniform nano-silver particles and the nano-silver particles have good crystallinity and obvious sintering phenomena at about 150?.Screening suitable base rubber system,SiO2@Ag and silver flakes were uesd as conductive fillers,the effects of the amount and ratio of SiO2@Ag on the performance of conductive adhesives were studied.By adjusting the ratio of SiO2@Ag,the conductive adhesive with good electrical conductivity,extremely low thermal expansion coefficient and excellent mechanical properties was prepared.The thermal expansion coefficient of the conductive adhesive with SiO2@Ag could be reduced to 20/43 ppm,which was far lower than the thermal expansion coefficient of the conventional conductive adhesive.The volume resistivity of the conductive adhesive was reduced to5.0×10-5?.cm and the mechanical and handling properties significantly improved. |
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