Patent ID: 7534723
Filing Date: 2009-05-19
Classification: H01L

Abstract:
1. A method of forming a trench isolation layer, comprising: forming masks having a first width and spaced apart from each other by a second width smaller than the first width on a substrate, each of the masks including a lower preliminary hard mask pattern, a preliminary buffer insulating pattern, and an upper preliminary hard mask pattern which are sequentially stacked on the substrate; forming first preliminary insulating spacers on sidewalls of the masks; etching the substrate using the upper preliminary hard mask patterns and the first preliminary insulating spacers as etch masks to form first trenches, predetermined regions of the first preliminary insulating spacers being etched to form first insulating spacers exposing sidewalls of the upper preliminary hard mask patterns during the formation of the first trenches; pulling back the upper preliminary hard mask patterns, thereby forming upper hard mask patterns on the preliminary buffer insulating patterns; forming a first preliminary trench isolation layer on the substrate having the upper hard mask patterns, the first preliminary trench isolation layer exposing top surfaces of the upper hard mask patterns; sequentially etching the upper hard mask patterns, the preliminary buffer insulating patterns disposed below the upper hard mask patterns, the lower preliminary hard mask patterns, and the substrate using the first preliminary trench isolation layer as an etch mask, thereby forming second trenches within the substrate; forming a second preliminary trench isolation layer on the substrate having the second trenches; and planarizing the first and second preliminary trench isolation layers, thereby forming first and second trench isolation layers filling the first and second trenches, respectively.