Method for planarizing semiconductor structures

摘要

A method for planarizing a semiconductor structure is disclosed. A semiconductor substrate having a first area in which one or more trenches are formed in a first pattern density, and a second area in which one or more trenches are formed in a second pattern density lower than the first pattern density, is provided. A first dielectric layer is formed above the semiconductor for covering the trenches in the first and second areas. A first chemical mechanical polishing is performed on the first dielectric layer using a predetermined type of slurry for reducing a thickness thereof. The first dielectric layer is then rinsed. A second chemical mechanical polishing is performed on the first dielectric layer using the predetermined type of slurry for further removing the first dielectric layer outside the trenches, thereby reducing a step height variation between surfaces of the first and second areas.