Method for forming patterned mask layer

A method for forming a patterned mask layer, comprising:

• forming a layer over a substrate;
• forming a first strip structure and a second strip structure over the layer;
• forming a spacer layer between the first strip structure and the second strip structure, wherein the spacer layer has a first strip part, a second strip part, and a connecting part, the first strip part and the second strip part are parallel to each other and spaced apart from each other, the connecting part is connected between the first strip part and the second strip part, the spacer layer has a first trench and a second trench spaced apart from the first trench, the connecting part separates the first trench from the second trench, and the first trench and the second trench pass through the spacer layer;
• forming a third strip structure and a fourth strip structure in the first trench and the second trench respectively;
• and
• removing the spacer layer, wherein the first strip structure, the second strip structure, the third strip structure, and the fourth strip structure together form a patterned mask layer.

A method for forming a patterned mask layer, comprising:

• forming a layer over a substrate;
• forming a first strip structure and a second strip structure over the layer;
• forming a spacer layer and a block structure between the first strip structure and the second strip structure, wherein the spacer layer has a first trench and a second trench spaced apart from each other and exposing portions of the layer, and the block structure is over the spacer layer between the first trench and the second trench;
• forming a third strip structure and a fourth strip structure in the first trench and the second trench respectively, wherein the block structure is between the third strip structure and the fourth strip structure;
• removing the block structure;
• and
• removing the spacer layer, wherein the first strip structure, the second strip structure, the third strip structure, and the fourth strip structure together form a patterned mask layer.