Methods and structures for forming uniform fins when using hardmask patterns

A method for manufacturing a semiconductor device, comprising:

• forming a plurality of patterned hardmask portions on a substrate, wherein each of the patterned hardmask portions are spaced apart from each other along the substrate in a horizontal direction with respect to a top surface of the substrate;
• forming a plurality of patterned dummy hardmask portions on the substrate which includes
• conformally depositing a dummy hardmask layer on the substrate and on the plurality of patterned hardmask portions,
• patterning the dummy hardmask layer to form the plurality of patterned dummy hardmask portions,
• wherein each of the plurality of patterned dummy hardmask portions is positioned adjacent respective outermost patterned hardmask portions of the plurality of patterned hardmask portions;
• etching portions of the substrate to form a plurality of fins under the plurality of patterned hardmask portions and a plurality of dummy fins under the plurality of patterned dummy hardmask portions, wherein the plurality of patterned hardmask portions and the plurality of patterned dummy hardmask portions are used as masks during the etching;
• and selectively removing the plurality of patterned dummy hardmask portions from the plurality of dummy fins with respect to the plurality of patterned hardmask portions.