Patent ID: 7601647
Filing Date: 2009-10-13
Classification: H01L

Abstract:
1. A method of forming fine patterns of a semiconductor device comprising: forming a hardmask layer in a first region and a second region of a substrate including an etch film that is to be etched; forming a plurality of mask patterns and buffer layer on the hardmask layer, wherein the plurality of mask patterns are repeatedly formed by having a first pattern density in the first region and having a second pattern density greater than the first pattern density in the second region, and wherein the buffer layer covers both sidewalls of the mask patterns in the second region; first etching by reactive ion etching (RIE) the buffer layer and the hardmask layer both in the first region and the second region under a first etching ambient until a first surface of the etch film is exposed in the first region using the mask patterns as an etch mask; second etching for forming hardmask patterns, under a state that the first surface of the etch film is exposed in the first region and the etch film is not exposed in the second region, by etching the hardmask layer until the second surface of the etch film is exposed in the second region while accumulating polymer by-products on the first surface of the etch film exposed in the first region under a second etching ambient having polymer by-products produced much greater than in the first etching ambient using the mask patterns as an etch mask; removing the polymer by-products accumulated on the first surface in order to expose the first surface of the etch film; and forming etch film patterns by etching the exposed first surface and the second surface of the etch film using the hardmask patterns as an etch mask.