Abstract: A method for forming a semiconductor with overetched spacer is disclosed. The method includes firstly providing a semiconductor substrate with a gate oxide layer formed thereon, and forming a polysilicon layer on the gate oxide layer. Next, a photoresist layer is formed on the polysilicon layer to define a gate area, followed by anisotropically etching the polysilicon layer and the gate oxide layer. A first dielectric layer is conformably formed, and a second dielectric layer is then formed thereon. After anisotropically etching the second dielectric layer to form a first sidewall spacer on the sidewall of the first dielectric layer, a third dielectric layer is further formed over the exposed first dielectric layer and the first sidewall spacer.