Lithography using high selectivity spacers for pitch reduction

A method for patterning a semiconductor device comprising:

• forming dummy lines over a hard mask;
• conformably forming a high selectivity spacer over the dummy lines;
• forming a first reverse material layer over the high selectivity spacer;
• etching back the first reverse material layer to expose a top surface of the high selectivity spacer;
• forming and patterning a photoresist over the first reverse material layer;
• selectively etching the first reverse material layer using the photoresist as a mask;
• forming a patterned second reverse material layer over portions of the high selectivity spacer;
• removing the dummy lines;
• exposing portions of the hard mask;
• and
• patterning the hard mask using the high selectivity spacer, the first reverse material layer, and the second reverse material layer as a mask.

A method for patterning a semiconductor device comprising:

• patterning a dummy layer over a hard mask layer in the semiconductor device to form one or more dummy lines;
• conformably forming a high selectivity spacer over the one or more dummy lines and the hard mask;
• forming a first reverse material layer over the high selectivity spacer;
• etching back a top portion of the first reverse material layer to a level below a top surface of the high selectivity spacer;
• patterning a photoresist over the first reverse material layer;
• selectively etching the first reverse material layer using the photoresist as a mask, wherein the high selectivity spacer is not etched;
• forming a second reverse material layer over portions of the high selectivity spacer, wherein a top surface of the second reverse material layer is lower than a top surface of the high selectivity spacer;
• etching back a top portion of the high selectivity spacer to expose the one or more dummy lines and exposing portions of the hard mask;
• removing the dummy lines;
• and
• patterning the hard mask using the high selectivity spacer and the first and second reverse material layers as a mask.