Processes to pattern small features for advanced patterning needs

A method of forming a microelectronic structure, said method comprising:

• providing a stack comprising a substrate having a surface, an optional intermediate layer adjacent said substrate surface, and a first pattern formed in and/or on said substrate surface or intermediate layer, when present, said first pattern comprising a plurality of initial features formed on said substrate surface or intermediate layer, wherein said initial features formed on said substrate surface or intermediate layer each have a height;
• forming an undercuttable layer adjacent said substrate surface or intermediate layer, when present, at an average thickness substantially equal to or greater than the height of said initial features;
• forming an imaging layer on said undercuttable layer and initial features;
• patterning said imaging layer to yield a second pattern;
• transferring said second pattern into said undercuttable layer, wherein said transferring yields a plurality of T-shaped structures on said substrate surface, or on an intermediate layer on said substrate surface, each of said T-shaped structures comprising:
• an upright leg having an upper portion and a lower portion joined by opposing vertical sidewalls that are generally perpendicular to said substrate surface, and a core corresponding to said initial features, said lower portion contacting said substrate surface or intermediate layer;
• and
• a generally horizontal section being adjacent said upper portion, and generally perpendicular to said vertical sidewalls, said generally horizontal section comprising an upper surface and a lower surface joined by opposing endwalls, wherein each of said vertical sidewalls and said lower surface cooperatively define a set of undercut areas;
• and
• filling said set of undercut area with a selectively etchable composition.

A method of forming a microelectronic structure, said method comprising:

• providing a wafer stack comprising a substrate having a surface, an optional intermediate layer adjacent said substrate surface, an undercuttable layer adjacent said substrate surface or optional intermediate layer, when present, and an imaging layer adjacent said undercuttable layer;
• patterning said imaging layer to yield a pattern, wherein said patterning comprises:
• exposing said imaging layer to light to yield light-exposed portions of the imaging layer;
• and
• contacting said imaging layer with a developer after light exposure so as to remove said light-exposed portions;
• transferring said pattern into said undercuttable layer, wherein said transferring yields a first plurality of T-shaped structures on said substrate surface, or on an intermediate layer on said substrate surface, said T-shaped structures each comprising:
• an upright leg having an upper portion and a lower portion joined by opposing vertical sidewalls that are generally perpendicular to said substrate surface, said lower portion contacting said substrate surface or intermediate layer;
• and
• a generally horizontal section being adjacent said upper portion. and generally perpendicular to said vertical sidewalls, said generally horizontal section comprising an upper surface and a lower surface joined by opposing endwalls, wherein each of said vertical sidewalls and said lower surface cooperatively define a first set of undercut areas;
• said undercuttable layer being developer-soluble, wherein said contacting removes portions of said undercuttable layer adjacent said light-exposed portions of the imaging layer to yield said T-shaped structures;
• filling said first set of undercut area with a selectively etchable composition;
• and
• removing said T-shaped structures to yield a first plurality of undercut-formed features on said substrate surface or intermediate layer, when present.

A method of forming a microelectronic structure, said method comprising:

• providing a wafer stack comprising a substrate having a surface, an optional intermediate layer adjacent said substrate surface, an undercuttable layer adjacent said substrate surface or optional intermediate layer, when present, and an imaging layer adjacent said undercuttable layer;
• patterning said imaging layer to yield a pattern;
• transferring said pattern into said undercuttable layer, wherein said transferring yields a first plurality of T-shaped structures on said substrate surface, or on an intermediate layer on said substrate surface, said T-shaped structures each comprising:
• an upright leg having an upper portion and a lower portion joined by opposing vertical sidewalls that are generally perpendicular to said substrate surface, said lower portion contacting said substrate surface or intermediate layer;
• and
• a generally horizontal section being adjacent said upper portion, and generally perpendicular to said vertical sidewalls, said generally horizontal section comprising an upper surface and a lower surface joined by opposing endwalls, wherein each of said vertical sidewalk and said lower surface cooperatively define a first set of undercut areas;
• filling said first set of undercut area with a selectively etchable composition;
• removing said T-shaped structures to yield a first plurality of undercut-formed features on said substrate surface or intermediate layer, when present;
• forming a second undercuttable layer adjacent said substrate surface or intermediate layer, when present, at an average thickness substantially equal to or greater than the height of said first plurality of undercut-formed features;
• forming said second imaging layer on said second undercuttable layer and first plurality of undercut formed features;
• patterning said second imaging layer to yield a second pattern;
• transferring said second pattern into said second undercuttable layer, wherein said transferring yields a second plurality of T-shaped structures on said substrate surface, or on an intermediate layer on said substrate surface, each of said second T-shaped structures comprising:
• an upright leg having an upper portion and a lower portion joined by opposing vertical sidewalls that are generally perpendicular to said substrate surface, and a core corresponding to said first plurality of undercut-formed features, said lower portion contacting said substrate surface or intermediate layer;
• and
• a generally horizontal section being adjacent said upper portion, and generally perpendicular to said vertical sidewalls, said generally horizontal section comprising an upper surface and a lower surface joined by opposing endwalls, wherein each of said vertical sidewalls and said lower surface cooperatively define a second set of undercut areas.