a heat dissipation substrate comprising a phase change structure and a heat conductive layer wrapping the phase change structure, the heat dissipation substrate defining a first through hole;

an insulating layer disposed on the heat dissipation substrate, the insulating layer defining a groove;

an electronic component mounted in the groove and in thermal conduction with the heat conductive layer;

a base layer disposed on the insulating layer, the electronic component being between the base layer and the insulating layer; and

a circuit layer disposed on the base layer;

wherein a second through hole is defined in the circuit layer, the base layer, and the insulating layer, a bottom of the second through hole corresponds to the heat conductive layer, and a heat conductive portion is disposed in the second through hole;

wherein the heat dissipation substrate comprises:

a first substrate defining a first receiving groove and a first blind hole, a first phase change layer disposed in the first receiving groove, a solder layer disposed in the first blind hole, the first substrate further defining a first opening penetrating through the first substrate; and

a second substrate defining a second receiving groove and a second blind hole, a second phase change layer disposed in the second receiving groove, a connecting post disposed in the second blind hole, an end of the connecting post protruding from the second substrate, the second substrate further defining a second opening penetrating through the second substrate;

wherein the connecting post is disposed in the first blind hole and connected to the solder layer, the first opening and the second opening connect to each other to form the first through hole, the first phase change layer and the second phase change layer connect to each other to form the phase change structure.