A method of forming a semiconductor package includes forming an interconnecting structure on an adhesive layer, wherein the adhesive layer is on a carrier. The method further includes placing a semiconductor die on a surface of the interconnecting structure. The method further includes placing a package structure on the surface of the interconnecting structure, wherein the semiconductor die fits in a space between the interconnecting structure and the package structure. The method further includes performing a reflow to bond the package structure to the interconnecting structure.