Integrated Circuits with Reduced Pitch and Line Spacing and Methods of Forming the Same

A method comprising:

• forming a mandrel layer over a target layer;
• performing a first lithography-and-etching process to pattern the mandrel layer;
• performing a second lithography-and-etching process and a cut-etch process to pattern remaining portions of the mandrel layer to form a first opening in the mandrel layer, wherein the first opening has an I-shape and comprises:
• two parallel portions, wherein the two parallel portions are formed by the first lithography-and-etching process and the second lithography-and-etching process;
• and
• a connecting portion interconnecting the two parallel portions;
• forming spacers on sidewalls of the first opening, wherein the spacers fill an entirety of the connecting portion, and wherein a center portion of each of the two parallel portions is unfilled by the spacers;
• etching the mandrel layer to remove a portion of the mandrel layer and to form a second opening, wherein the second opening is between the two parallel portions of the first opening, and wherein the second opening is spaced apart from the two parallel portions of the first opening by the spacers;
• and
• extending the first opening and the second opening into the target layer.

A method comprising:

• forming a mandrel layer over a target layer;
• performing a first lithography-and-etching process to pattern the mandrel layer, wherein remaining portions of the mandrel layer comprise a first intermediate mandrel and a second intermediate mandrel are formed;
• performing a second lithography-and-etching process, wherein a size of the first intermediate mandrel is reduced to form a first mandrel, and the second intermediate mandrel is cut into a second mandrel and a third mandrel, and wherein the first mandrel, the second mandrel, and the third mandrel are parallel to each other, with the second mandrel being between the first mandrel and the third mandrel;
• etching the second mandrel to cut the second mandrel into a fourth mandrel and a fifth mandrel, with an opening separating the fourth mandrel from the fifth mandrel;
• forming a spacer layer on sidewalls of the first mandrel, the second mandrel, the fourth mandrel, and the fifth mandrel, wherein the opening is fully filled by the spacer layer;
• and
• removing horizontal portions of the spacers, with vertical portions of the spacer layer remaining un-removed.