The invention provides an LTCC substrate with built-in microchannels and
high heat dissipation performance as well as a manufacturing method thereof. The LTCC substrate comprises an upper layer part,a middle layer part and a lower layer part; the upper layer part is provided with a
metal column array, the middle layer part is provided with a cavity formed by two microchannels and a hollow cavitywhich are communicated, the hollow cavity is internally provided with a
metal column array, and
metal columns of the upper layer part and metal columns of the middle layer part are in one-to-one correspondence; and the lower layer part is provided with a cooling liquid outlet / inlet hole. The manufacturing method comprises the following steps: preparing a carbon belt
green body sample with a metalcolumn array and a pure carbon belt
green body sample; preparing an upper layer green
ceramic disc, a middle layer green
ceramic disc and a lower layer green
ceramic disc respectively corresponding tothe upper layer part, the middle layer part and the lower layer part; and laminating the carbon belt
green body sample and the green ceramic discs in a corresponding manner, and
sintering. The substrate provided by the invention is provided with the metal column arrays, the cavity and the microchannels, and the metal column array in an upper layer transfers heat produced by a
chip to the metal column array in a middle layer; and the metal column array in the middle layer transfers heat to a heat dissipation medium inside the cavity by virtue of increased surface area, so that the heat dissipation performance of the substrate is improved.