Method for forming contact hole

摘要

A method for forming contact holes includes following steps. A substrate including a dense region and an isolation region is provided. A material layer is formed on the substrate. Sacrificed patterns are formed on the material layer in the dense region, wherein there is a first opening between the two adjacent sacrificed patterns. A spacer is formed on each of two sides of each of the sacrificed patterns, wherein the spacers are separated from each other. The sacrificed patterns are removed to form a second opening between two adjacent spacers. A planar layer is formed to fill up the second openings. A first slit is formed in the planar layer, wherein the first slit exposes a portion of the material layer under the second openings. The portion of the material layer exposed by the first slit is removed to form third openings in the material layer.