A semiconductor device includes a chip having an active surface and a rear surface that is opposite to the active surface; a molding compound covering and encapsulating the chip except for the active surface; and a redistribution layer (RDL) on the active surface and on the molding compound. The RDL is electrically connected to the chip. The RDL includes an organic dielectric layer and an inorganic dielectric hard mask layer on the organic dielectric layer. The RDL further includes metal features in the organic dielectric layer and the inorganic dielectric hard mask layer.