A packaging substrate includes a first dielectric layer; a plurality of first conductive pads embedded in and exposed from a first surface of the first dielectric layer; a first circuit layer embedded in and exposed from a second surface of the first dielectric layer; a plurality of first metal bumps disposed in the first dielectric layer, each of the first metal bumps having a first end embedded in the first circuit layer and a second end opposing the first end and disposed on one of the first conductive pads, a conductive seedlayer being disposed between the first circuit layer and the first dielectric layer and between the first circuit layer and the first metal bump; a built-up structure disposed on the first circuit layer and the first dielectric layer; and a plurality of second conductive pads disposed on the built-up structure. The packaging substrate has an over-warpage problem improved.