Patent ID: 7754591

Claim:
A method for forming a fine pattern of a semiconductor device, the method comprising: a) forming a stack structure including a 1 st layer hard mask film through an n th layer hard mask film over an underlying layer; b) etching the n th layer hard mask film to obtain first hard mask patterns of the n th layer; c) forming a second hard mask film of the n th layer over the first hard mask patterns of the n th layer and planarizing the second hard mask film until the first hard mask patterns of the n th layer are exposed; d) removing an upper portion of the exposed first hard mask patterns of the n th layer, so that an upper surface of the resulting first hard mask patterns are lower than an upper surface of the second hard mask film of the n th layer; e) performing a first trimming process on the second hard mask film of the n th layer to form second hard mask patterns of the n th layer having sloped sidewalls; f) performing a second trimming process on the second hard mask patterns of the n th layer to form a third hard mask pattern of the n th layer between each pair of adjacent first hard mask patterns of the n th layer; g) patterning an (n−1) th layer hard mask film using the first and the second hard mask patterns of the n th layer as etching masks to form first hard mask patterns of an (n−1) th layer; h) repeating the (c) step to the (g) step to form first and second hard mask patterns of the 1 st layer over the underlying layer; and i) patterning the underlying layer using the first and second hard mask patterns of the 1 st layer as etching masks.