Abstract: A thin flip chip package structure comprises a substrate, a chip and a heat dissipation paste, the substrate comprises an insulating layer and a trace layer. The insulating layer comprises a top surface, a bottom surface and a plurality of apertures formed at the bottom surface, wherein the bottom surface of the insulating layer comprises a disposing area and a non-disposing area. Each of the apertures is located at the disposing area and comprises a lateral wall and a base surface. A first thickness is formed between the base surface and the insulating layer, a second thickness is formed between the top surface and the bottom surface, and the second thickness is larger than the first thickness. The chip disposed on the top surface comprises a chip surface and a plurality of bumps. The heat dissipation paste at least fills the apertures and contacts the base surface.