Method of reverse tone patterning

A method of forming a pattern with reverse tone features, wherein the reverse tone features include a small feature reverse tone feature and a transition zone reverse tone feature, the small feature reverse tone feature is in a small feature region, the transition zone reverse tone feature is in a transition zone, the transition zone is between a large feature and the small feature region, a transition zone critical dimension of a transition zone reverse tone feature is consistent with a small feature critical dimension of the small feature reverse tone feature, the method comprising:

• forming a patterned layer on a substrate, the patterned layer defining a relief pattern having non-uniformly sized features;
• depositing a conformal hard mask layer by low temperature deposition over the patterned layer features;
• applying a non-planar protective layer over the conformal layer, the protective layer having a planarity efficiency PE of less than 95% (PE 95%);
• the non-planar protective layer has a characteristic spatial parameter (sp), which is used for characterization of the planarity efficiency;
• wherein small features in the small feature region have a lateral size (s), in at least one in-plane direction that are less than the characteristic spatial parameter (sp) (s<sp);
• wherein the large feature is an open area that has two lateral sizes in-plane dimensions (s1 and s2) that are at least the characteristic spatial parameter (sp) (s1 and s2>sp);
• wherein the protective layer has an etch selectivity ξ1 relative to the conformal hard mask layer of at least 5 (ξ1≥5) under first etch conditions;
• wherein a first region over the large feature of a top surface of the non-planar protective layer prior to being etched under the first etch conditions forms a depression relative to a second region over the small feature region of the top surface of the non-planar protective area prior to being etched under the first etch conditions;
• and
• wherein the conformal hard mask layer has an etch selectivity ξ2 relative to the protective layer of greater than (ξ2>1) under second etch conditions;
• wherein the patterned layer has an etch selectivity ξ3 relative to the conformal hard mask layer of at least 5 (ξ3≥5) under third etch conditions;
• selectively etching the protective coating under the first etch conditions to expose the top surface of the conformal hard mask layer extending over the tops of the pattern protruded features;
• selectively etching the exposed conformal hard mask layer under the second etch conditions to expose the pattern features thereunder;
• and
• selectively etching the exposed pattern features under the third etch conditions to expose the substrate and forming the pattern with reverse tone features that is the reverse of the relief pattern.

A method of forming a pattern with reverse tone features, wherein the reverse tone features include a small feature reverse tone feature and a transition zone reverse tone feature, the small feature reverse tone feature is in a small feature region, the transition zone reverse tone feature is in a transition zone, the transition zone is between a large feature and the small feature region, a transition zone critical dimension of a transition zone reverse tone feature is consistent with a small feature critical dimension of the small feature reverse tone feature, the method comprising:

• forming a patterned layer on a substrate, the patterned layer defining a relief pattern having non-uniformly sized features;
• depositing a conformal hard mask layer by low temperature deposition over the patterned layer features;
• applying a non-planar protective layer over the conformal layer,
• wherein the non-planar protective layer over the transition zone has a first planarization profile and the non-planar protective layer over the small feature region has a second planarization profile that is different from the first planarization profile;
• wherein the non-planar protective layer has a characteristic spatial parameter (sp), which is used for characterization of the planarity efficiency of the non-planar protective layer;
• wherein small features in the small feature region have a lateral size (s), in at least one in-plane direction that are less than the characteristic spatial parameter (sp) (s<sp);
• wherein the large feature is an open area that has two lateral sizes in-plane dimensions (s1 and s2) that are at least the characteristic spatial parameter (sp) (s1 and s2>sp);
• wherein the protective layer has an etch selectivity ξ1 relative to the conformal hard mask layer under first etch conditions;
• wherein a first region over the large feature of a top surface of the non-planar protective layer prior to being etched under the first etch conditions forms a depression relative to a second region over the small feature region of the top surface of the non-planar protective area prior to being etched under the first etch conditions;
• and
• wherein the conformal hard mask layer has an etch selectivity ξ2 relative to the protective layer under second etch conditions;
• wherein the patterned layer has an etch selectivity ξ3 relative to the conformal hard mask layer under third etch conditions;
• selectively etching the protective coating under the first etch conditions to expose the top surface of the conformal hard mask layer extending over the tops of the pattern protruded features;
• selectively etching the exposed conformal hard mask layer under the second etch conditions to expose the pattern features thereunder;
• and
• selectively etching the exposed pattern features under the third etch conditions to expose the substrate and forming the pattern with reverse tone features that is the reverse of the relief pattern;
• and
• wherein the etch selectivity ξ1, the etch selectivity ξ2, and the etch selectivity ξ3 compensate for differences between the second planarization profile and the first planarization profile to ensure that the transition zone reverse tone feature is consistent with the small feature critical dimension.