Method for fabricating semiconductor memory device

A method for fabricating a semiconductor device, comprising:

• forming an etch-target layer over a substrate having a first region and a second region;
• stacking a first hard mask layer and a second hard mask layer over the etch-target layer, the second hard mask layer having an etching selectivity with the first hard mask layer;
• forming spacer patterns over the second hard mask layer of the first region;
• etching the second hard mask layer using the spacer patterns as an etch barrier;
• forming a hard mask pattern over the first hard mask layer of the second region;
• etching the first hard mask layer using the second hard mask layer of the first region and the hard mask pattern of the second region as etch barriers;
• removing the hard mask pattern of the second region;
• and
• etching the etch-target layer using the first and second hard mask layers of the first region and the first hard mask layer of the second region as etch barriers.