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 mask lines along 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 mask lines along sidewalls of the second plurality of mandrels, the second plurality of mask lines elongated generally parallel to the first plurality of the first and second pluralities of mask lines; selectively removing, relative to the mask lines, portions of exposed material on the first and second levels to form a pattern defined by mask lines of the first and the second pluralities of mask lines; transferring the pattern to an underlying material, wherein transferring the pattern to the underlying material comprises transferring the pattern to an amorphous carbon layer; and subsequently transferring the pattern to the substrate.