METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

Provided is a method for manufacturing a semiconductor device, in which a mask layer, a buffer layer, and a first mandrel layer are sequentially stacked on a substrate including a first region and a second region. First mandrel patterns are formed on the buffer layer in the first region, and a second mandrel pattern covering the buffer layer in the second region is formed. A first spacer contacting side walls of the first mandrel pattern and the second mandrel pattern is formed on the buffer layer. The first mandrel patterns are removed. A buffer layer pattern and a preliminary mask pattern are formed on the substrate. The second mandrel pattern is removed. In addition, a mask pattern is formed. The buffer layer includes a material having lower electrical conductivity than the mask layer and having etching selectivity with respect to the mask layer.