Sidewall image transfer process employing a cap material layer for a metal nitride layer

A method of patterning a structure comprising:

• forming a metal nitride layer on a substrate;
• forming a cap material layer having a different composition than said metal nitride layer directly on said metal nitride layer;
• forming a stack of an organic planarizing layer (OPL) and an antireflective coating (ARC) layer on said cap material layer;
• forming patterned line structures comprising a dielectric material on said ARC layer;
• etching said cap material layer and at least one of said patterned line structures and said ARC layer employing at least said patterned line structures as an etch mask, wherein a pattern present in said ARC layer is transferred through said OPL and said cap material layer, and a top surfaces of said metal nitride layer is exposed after said etching;
• transferring said pattern from said OPL into said metal nitride layer;
• and
• transferring said pattern from said metal nitride layer into an upper portion of said substrate.

A method of patterning a structure comprising:

• forming a metal nitride layer on a substrate;
• forming a cap material layer having a different composition than said metal nitride layer directly on said metal nitride layer;
• forming a stack of an organic planarizing layer (OPL) and an antireflective coating (ARC) layer on said cap material layer;
• forming mandrels having parallel sidewalls on said ARC layer;
• depositing a conformal dielectric layer on said parallel sidewalls and exposed surfaces of said ARC layer;
• anisotropically etching said conformal dielectric layer, wherein remaining portions of said conformal dielectric layer form patterned line structures on said parallel sidewalls of said mandrels;
• etching said cap material layer and at least one of said patterned line structures and said ARC layer, wherein a pattern present in said ARC layer is transferred through said OPL and said cap material layer, and a top surfaces of said metal nitride layer is exposed after said etching;
• transferring said pattern from said OPL into said metal nitride layer;
• and
• transferring said pattern from said metal nitride layer into an upper portion of said substrate.