Mechanisms for forming patterns using multiple lithography processes

A method for forming patterns in a semiconductor device, comprising:

• providing a substrate and a patterning-target layer over the substrate;
• patterning the patterning-target layer to form a main pattern;
• forming a middle layer over the patterning-target layer;
• forming a hard mask layer over the middle layer;
• patterning the hard mask layer to form a first cut pattern;
• forming a first resist layer over the hard mask layer;
• patterning the first resist layer to form a second cut pattern,
• patterning the middle layer through an opening corresponding to a first intersection portion to expose a portion of the patterning-target layer, the exposed portion of the patterning-target layer corresponding to a second intersection portion;
• forming a fill layer to fill the opening;
• etching the middle layer using the fill layer and the hard mask layer as etching masks to expose one or more portions of the patterning-target layer;
• and
• etching the one or more exposed portions of the patterning-target layer using the fill layer and the hard mask layer as etching masks to form a final pattern in the patterning-target layer,
• wherein the first intersection portion corresponds to an intersection between the first cut pattern and the second cut pattern, and
• wherein the second intersection portion corresponds to an intersection between the first intersection portion and the main pattern.

A method for forming patterns in a semiconductor device, comprising:

• forming a patterning-target layer over a substrate;
• forming a main pattern in the patterning-target layer;
• forming a film stack over the patterning-target layer, the film stack including a middle layer, a hard mask layer, and a first resist layer;
• forming a first cut pattern in the first resist layer;
• forming a second cut pattern in the first resist layer;
• patterning the middle layer through an opening corresponding to a first intersection portion to expose a portion of the patterning-target layer, the exposed portion of the patterning-target layer corresponding to a second intersection portion;
• forming a fill layer to fill the opening;
• etching the middle layer using the fill layer and the hard mask layer as etching masks to expose one or more portions of the patterning-target layer;
• and
• etching the one or more exposed portions of the patterning-target layer using the fill layer and the hard mask layer as etching masks to form a final pattern in the patterning-target layer,
• wherein the first intersection portion corresponds to an intersection between the first cut pattern and the second cut pattern, and
• wherein the second intersection portion corresponds to an intersection between the first intersection portion and the main pattern.