Method for manufacturing semiconductor structure using multi-layered hard mask

A method for manufacturing a semiconductor structure, comprising:

• forming a base structure having a first region and a second region displaced from the first region;
• forming a hard mask unit, the hard mask unit having a first portion and a second portion which are respectively formed on the first region and the second region, each of the first portion and the second portion of the hard mask unit including an inner layer and an outer layer that are sequentially formed on the base structure;
• forming a patterned polymeric mask over the second portion of the hard mask unit, the first portion of the hard mask unit being exposed from the patterned polymeric mask;
• after forming the patterned polymeric mask, performing a first removing process to sequentially remove the outer layer and the inner layer of the first portion of the hard mask unit;
• and
• after the first removing process, performing a second removing process to remove the patterned polymeric mask.

A method for manufacturing a semiconductor structure, comprising:

• forming a base structure on a substrate, the base structure having a first region and a second region displaced from the first region, each of the first region and the second region including:
• two source/drain features formed on the substrate;
• and
• channel features that are spaced apart from each other in a vertical direction and that interconnect the two source/drain features;
• forming a hard mask unit, the hard mask unit having a first portion and a second portion which are respectively formed on the first region and the second region, each of the first portion and the second portion of the hard mask unit including an inner layer and an outer layer that are sequentially formed on the channel features and that are made of different materials;
• forming a patterned polymeric mask over the second portion of the hard mask unit, the first portion of the hard mask unit being exposed from the patterned polymeric mask;
• after forming the patterned polymeric mask, performing a first removing process to remove the first portion of the hard mask unit;
• and
• after the first removing process, performing a second removing process to remove the patterned polymeric mask.