Package substrate and manufacturing method thereof

A package substrate, comprising:

• a core layer, having a first surface and a second surface opposite each other, and at least one opening and a plurality of conductive through vias connecting the first surface and the second surface;
• at least one functional component, disposed in the at least one opening of the core layer, wherein the at least one opening exposes at least one action surface of the at least one functional component;
• at least one spacer, disposed on the at least one functional component and having at least one top surface relatively away from the at least one functional component;
• a filler, filled in the at least one opening and having a third surface and a fourth surface opposite each other, wherein the filler covers the at least one functional component and the at least one spacer and completely fills a gap between the at least one opening, the at least one functional component, and the at least one spacer, the third surface exposes the at least one action surface of the at least one functional component, and the fourth surface exposes the at least one top surface of the at least one spacer;
• a first build-up structure, disposed on the first surface of the core layer and the third surface of the filler and electrically connected to the at least one functional component and the conductive through vias;
• and
• a second build-up structure, disposed on the second surface of the core layer and the fourth surface of the filler, contacting the at least one top surface of the at least one spacer, and electrically connected to the conductive through vias.