Semiconductor device and method of fabricating the same

A method of fabricating a semiconductor device, comprising:

• sequentially forming a lower mask layer and an upper mask layer on a substrate having a first region and a second region therein;
• forming a first mask pattern and a second mask pattern, which are respectively placed on the first region and the second region, on the upper mask layer;
• removing a portion of the upper mask layer, which is exposed by the second mask pattern, from the second region;
• then
• removing the first mask pattern from the first region;
• and
• forming an upper mask pattern by etching a remaining portion of the upper mask layer on the first region and on the second region, using the second mask pattern as an etch mask,
• wherein the upper mask pattern covers the lower mask layer on the first region and exposes a portion of the lower mask layer on the second region.

A method of fabricating a semiconductor device, comprising:

• sequentially forming a lower mask layer and an upper mask layer on a substrate having a first region and a second region therein, wherein the second region includes a first sub-region and a second sub-region;
• forming a first mask pattern and a second mask pattern, which are respectively placed on the first region and the second region, on the upper mask layer, wherein the second mask pattern is vertically overlapped with the upper mask layer on the first sub-region and exposes the upper mask layer on the second sub-region;
• removing a portion of the upper mask layer on the second sub-region using the second mask pattern as an etch mask;
• then
• removing the first mask pattern from the first region;
• and
• forming an upper mask pattern by etching a remaining portion of the upper mask layer on the first region and on the second sub-region, using the second mask pattern as an etch mask,
• wherein a top surface of the upper mask pattern on the first region is located at a height that is substantially equal to or lower than a top surface of the upper mask pattern on the second region.

A method of fabricating a semiconductor device, comprising:

• sequentially forming a lower mask layer and an upper mask layer on a substrate having a first region and a second region therein, wherein the second region includes a first sub-region and a second sub-region;
• forming a first mask pattern and a second mask pattern, which are respectively placed on the first region and the second region, on the upper mask layer, wherein the second mask pattern is vertically overlapped with the upper mask layer on the first sub-region and exposes the upper mask layer on the second sub-region;
• removing a portion of the upper mask layer on the second sub-region using the second mask pattern as an etch mask, wherein a top surface of the lower mask layer on the second sub-region is covered by a remaining portion of the upper mask layer after the removing of the portion of the upper mask layer;
• then
• removing the first mask pattern from the first region;
• and
• forming an upper mask pattern by etching the remaining portion of the upper mask layer on the first region and on the second sub-region, using the second mask pattern as an etch mask.