Abstract: A method for fabricating a trench isolation structure is provided. The method includes providing a substrate and forming a patterned mask layer on the substrate. A first etching step is performed on the substrate by using the patterned mask layer to form a trench in the substrate. A dielectric material is formed in the trench and on the patterned mask layer, wherein the dielectric material on the patterned mask layer has a first height. An etch back step is performed to decrease the dielectric material on the patterned mask layer to a second height. A planarization process is performed to remove the dielectric material on the patterned mask layer, where a polishing pad is used, and a first pressure and a second pressure are respectively applied on a central portion and a peripheral portion of the polishing pad, wherein the second pressure is greater than the first pressure.

Abstract: A method for fabricating a trench isolation structure is provided. The method includes providing a substrate and forming a patterned mask layer on the substrate. A first etching step is performed on the substrate by using the patterned mask layer to form a trench in the substrate. A dielectric material is formed in the trench and on the patterned mask layer, wherein the dielectric material on the patterned mask layer has a first height. An etch back step is performed to decrease the dielectric material on the patterned mask layer to a second height. A planarization process is performed to remove the dielectric material on the patterned mask layer, where a polishing pad is used, and a first pressure and a second pressure are respectively applied on a central portion and a peripheral portion of the polishing pad, wherein the second pressure is greater than the first pressure.