A method for forming shallow trench isolation structures produces a shallow trench isolation structure having a substantially planar upper surface. The shallow trench isolation structure is formed from an originally formed shallow trench isolation structure which includes a deposited dielectric material within a trench and which exhibits dishing related problems in the form of a void formed within the trench, wherein the surface of the deposited dielectric material is recessed below the planar upper surface. The method provides for filling the void with a silicon film. The silicon film is then polished in its as-deposited or oxidized form, to produce a shallow trench isolation structure having a planar upper surface.