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, such that a first portion of the middle layer is exposed at an intersection of the first pattern and the second cut pattern;
• patterning the first portion of the middle layer to expose a first portion of the patterning-target layer;
• and
• etching the first portion of the patterning-target layer using the middle layer as an etching mask to form a final pattern in the patterning-target layer.

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;
• transferring the first cut pattern to the hard mask layer;
• forming a second resist layer over the hard mask layer;
• forming a second cut pattern in the second resist layer, such that a first portion of the hard mask layer is exposed, the first portion corresponding to a first intersection pattern formed from an intersection of the first cut pattern and the second cut pattern;
• transferring the first intersection pattern to the middle layer, such that a second portion of the middle layer is exposed, the second portion corresponding to a second intersection pattern formed from an intersection of the first intersection pattern and the main pattern;
• and
• transferring the second intersection pattern to the patterning-target layer to form a final pattern.