Patent ID: 7998874
Filing Date: 2011-08-16
Classification: H01L

Abstract:
1. A method for forming hard mask patterns, comprising: sequentially forming a first hard mask layer, a second hard mask layer, and a third hard mask layer on a substrate, each hard mask layer being formed of a material having a different etching selectivity with respect to an adjacent hard mask layer; forming first sacrificial patterns having a first pitch therebetween on the third hard mask layer, wherein forming the first sacrificial patterns includes: forming fourth hard mask patterns between the first sacrificial patterns, such that the fourth hard mask patterns have a second pitch therebetween, the second pitch being substantially equal to about ½ of the first pitch, wherein forming the fourth hard mask patterns includes forming a fourth hard mask layer having a uniform thickness on lateral and upper surfaces of each of the first sacrificial patterns, the thickness of the fourth hard mask layer being adjusted to form recess regions between the first sacrificial patterns; forming a second sacrificial film in the recess regions; removing upper portions of the second sacrificial film and of the fourth hard mask layer to form second sacrificial patterns and the fourth hard mask patterns, respectively; removing the first and second sacrificial patterns to expose upper surfaces of the etching prevention patterns and of bottom portions of the fourth hard mask patterns; etching back the etching prevention patterns and bottom portions of the fourth hard mask patterns to form reduced height fourth hard mask patterns on the third hard mask layer; patterning the third hard mask layer to form third hard mask patterns with the second pitch therebetween using the fourth hard mask patterns as an etch mask; patterning the second hard mask layer to form second hard mask patterns with the second pitch therebetween using the third and fourth hard mask patterns as an etch mask; and patterning the first hard mask layer to form first hard mask patterns with the second pitch therebetween using the second and third hard mask patterns as an etch mask.