The invention discloses a low temperature-sintered nano
silver paste and a preparation method thereof. The invention is characterized in that: by weight percent, the components of the nano
silver paste are as follows: 78.5 to 89.5 percent of nano silver
powder with the average grain size of 20nm to 50nm; 5.0 percent to 10.0 percent of
polyvinyl alcohol as organic carrier; 5.0 percent to 10.0 percent of
tributyl citrate as
organic solvent; and 0.5 percent to 1.5 percent of
abietic acid as surfactant. The nano
silver paste preparation method sequentially includes the following steps:
ethanol solution
water heating, component adding and mixing,
ultrasonic dispersion under zero DEG C, mechanical stirring and
vacuum drying. The
sintering temperature of the silver paste is notably decreased, and does not need to reach the
softening temperature of glass, moreover, the silver content of the sintered material is at least 98 percent, the nano silver paste has
high heat conductivity and high reliability, and the heat
conductivity of the nano silver paste is three to four times higher than the heat
conductivity of
alloy solder, and thereby the heat-dissipating problem of packaging is effectively solved. The low temperature-sintered nano silver paste is particularly suitable for use as novel thermal interface material for the
interconnection between power type chips in the field of
electronic packaging.