Provided is a method of fabricating a package including: providing a die with a contact thereon; forming a redistribution layer (RDL) structure on the die, the forming the RDL structure on the die comprising: forming a first dielectric material on the die; forming a conductive feature in and partially on the first dielectric material; after the forming the conductive feature, forming a protective layer on the conductive feature, wherein the protective layer covers a top surface of the conductive feature and extends to cover a top surface of the first dielectric material; forming a second dielectric material on the protective layer; and performing a planarization process to expose the conductive feature; and forming a plurality of conductive connectors to electrically connect the die through the RDL structure.