A method for manufacturing a semiconductor device includes providing a substrate having an NMOS transistor and a PMOS transistor formed thereon, forming a stressed layer that covers the transistors, and selectively removing the stressed layer on the PMOS transistor. The method further includes annealing the substrate, removing the remaining stressed layer, forming a dielectric layer structure on the transistors; and performing a first planarization process on the dielectric layer structure. The method also includes forming a corrosion-resistant insulating structure on a rear surface of the substrate, and performing a second planarization process on the dielectric layer structure. The semiconductor device thus formed can withstand high voltages while maintaining gate oxide integrity.