Method for manufacturing mask structure, semiconductor structure and manufacturing method thereof

A semiconductor structure, wherein the semiconductor structure is manufactured with a method comprising:

• providing a substrate;
• forming a material layer to be etched on the substrate;
• forming a first mask layer, a first buffer layer, a second mask layer, and a second buffer layer sequentially stacked from bottom to top;
• patterning the second buffer layer and the second mask layer, as to obtain a first pattern structure, the first pattern structure exposes a part of the first buffer layer;
• forming a first mask pattern on sidewalls of the first pattern structure;
• forming a carbon plasma layer as a protective layer on an exposed part of an upper surface of first buffer layer on an exposed upper surface of the first buffer layer;
• removing the first pattern structure;
• removing a remaining protective layer;
• based on the first mask pattern, patterning the first buffer layer and the first mask layer sequentially, as to obtain a target mask pattern;
• and
• based on the target mask pattern, etching the material layer to be etched, as to obtain the semiconductor structure;
• wherein a bit line contact hole is formed on the substrate;
• and forming the material layer to be etched on the substrate comprises:
• forming a polysilicon layer in the bit line contact hole and on the substrate;
• forming a conductive layer on an upper surface of the polysilicon layer;
• and
• forming a dielectric material layer on an upper surface of the conductive layer;
• wherein the target mask pattern is formed on an upper surface of the dielectric material layer.