Method for positioning spacers in pitch multiplication

摘要

Multiple pitch-multiplied spacers are used to form mask patterns having features with exceptionally small critical dimensions. One of each pair of spacers formed mandrels is removed and alternating layers, formed of two mutually selectively etchable materials, are deposited around the remaining spacers. Layers formed of one of the materials are then etched, leaving behind vertically-extending layers formed of the other of the materials, which form a mask pattern. Alternatively, instead of depositing alternating layers, amorphous carbon is deposited around the remaining spacers followed by a plurality of cycles of forming pairs of spacers on the amorphous carbon, removing one of the pairs of spacers and depositing an amorphous carbon layer. The cycles can be repeated to form the desired pattern. Because the critical dimensions of some features in the pattern can be set by controlling the width of the spaces between spacers, exceptionally small mask features can be formed.

主权项

1. A method for forming an integrated circuit, comprising:
forming a first plurality of mandrels on a first level over a substrate; forming a first plurality of spacers on sidewalls of the first plurality of mandrels; forming a second plurality of mandrels on a second level over the first level; forming a second plurality of spacers on the sidewalls of the second plurality of mandrels, the second plurality of spacers elongated generally parallel to the first plurality of spacers; selectively etching portions of material between spacers of each of the first and the second pluralities of spacers to form a pattern defined by spacers of the first and the second pluralities of spacers; and transferring the pattern to the substrate, wherein transferring the pattern to the substrate comprises:
transferring the pattern to an amorphous carbon layer; andsubsequently etching the pattern into the substrate.