the invention is directed to a method for manufacturing a fin field effect transistor including a fully silicidated gate electrode . the method is suitable for a substrate including a fin structure , a straddle gate , a source / drain region and a dielectric layer formed thereon , wherein the straddle gate straddles over the fin structure , the source / drain region is located in a portion of the fin structure exposed by the straddle gate and the dielectric layer covers the substrate . the method includes steps of performing a planarization process to remove a portion of the dielectric layer and the first salicide layer until the surface of the straddle gate is exposed and performing a salicide process to convert the straddle gate into a fully silicidated gate electrode .