The present invention provides a method for forming a semiconductor structure, including the following steps: first, a substrate is provided, an interlayer dielectric (ILD) is formed on the substrate, a first dummy gate is formed in the ILD, wherein the first dummy gate includes a dummy gate electrode and two spacers disposed on two sides of the dummy gate electrode respectively. Next, two contact holes are formed in the ILD at two sides of the first dummy gate respectively. Afterwards, the dummy gate electrode is removed, so as to form a gate recess in the ILD, a first material layer is filled in the gate recess and a second material layer is filled in the two contact holes respectively, and an anneal process is performed on the first material layer and the second material layer, to bend the two spacers into two inward curving spacers.