Pattern reduction by trimming a plurality of layers of different handmask materials

摘要

In a method for patterning a target material on a semiconductor substrate, a first hardmask material is deposited on the target material and a second hardmask material is deposited on the first hardmask material. The first hardmask material is different from the target material, and the second hardmask material is different from the first hardmask material. A patterned structure of a patterning material such a photoresist material is formed on the second hardmask material. Any exposed region of the second hardmask material is etched such that a second hardmask structure is formed from the second hardmask material remaining under the patterned structure. The etching reactant for etching the second hardmask material to form the second hardmask structure substantially does not etch the first hardmask material. The second hardmask structure is trimmed to reduce the length at each side of the second hardmask structure. Any exposed region of the first hardmask material is etched using a second etching reactant such that a first hardmask structure is formed from the first hardmask material remaining under the second hardmask structure. The second etching reactant substantially does not etch the second hardmask structure and the target material. The first hardmask structure is trimmed with a second trimming reactant to reduce the length at each side of first second hardmask structure. Any exposed region of the target material is etched using a third etching reactant such that a target structure is formed from the target material remaining under the first hardmask structure.