A method of making a package substrate includes steps of forming a plurality of trenches on a first surface of a metal plate, placing insulation material in the trenches, removing metal plate material under the second surface of the metal plate, and exposing the insulation material in the trenches from substrate. The resulting substrate body includes a conductive portion made of the metal plate, and an insulation portion made of the insulation material. The bonding layers on the opposite sides of the substrate are conducted by the conductive portion for heat dissipation, and are separated from one another by the insulation portion.