The present disclosure provides a method of semiconductor fabrication including forming a dielectric layer is formed on and interposing a first feature and a second feature. A first CMP process is performed on the dielectric layer to removing the dielectric layer from a top surface of the first feature to expose an underlying layer and decreasing a thickness of the dielectric layer disposed on a top surface of the second feature such that a portion of the dielectric layer remains disposed on the top surface of the second feature. Thereafter, a second CMP process is performed which removes the dielectric layer remaining on the top surface of the second feature.