Fabrication of an isolated dummy fin between active vertical fins with tight fin pitch

A method of forming an arrangement of active and inactive fins on a substrate, comprising:

• forming at least three vertical fins on the substrate;
• forming a protective liner on at least three of the at least three vertical fins;
• forming a filler layer on the at least three of the at least three vertical fins;
• forming a masking layer on at least a portion of the filler layer, wherein at least a portion of the protective liner on one of the at least three of the at least three vertical fins is exposed;
• removing at least a portion of the protective liner on the one of the at least three vertical fins;
• and
• converting the one of the at least three of the at least three vertical fins to an inactive vertical fin.

A method of forming an arrangement of active and inactive fins on a substrate, comprising:

• forming a plurality of active vertical fins on a substrate, wherein the active vertical fins are made of a semiconductor material;
• forming at least one inactive vertical fin adjacent to at least one of the plurality of active vertical fins, wherein the at least one inactive vertical fin is at least partially converted to an insulating material;
• and
• forming a dielectric layer on at least a portion of the plurality of active vertical fins.