Patent ID: 7749912

Claim:
A method for fabricating a bulb-shaped recess pattern, comprising: forming an etch barrier layer over a substrate; forming a hard mask layer over the etch barrier; forming a hard mask pattern whose sidewalls are coated with a first polymer generated during a step of etching a portion of the hard mask layer until the etch barrier layer is exposed, wherein the first polymer is formed only on the sidewalls of the hard mask pattern; forming a recess pattern whose sidewalls are coated with a second polymer generated during a step of etching the etch barrier layer and the substrate by using the hard mask pattern coated with the first polymer as an etch barrier; removing the first and second polymers and the hard mask pattern; forming a plurality of spacers exposing a bottom portion of the recess pattern; and etching the exposed bottom portion of the recess pattern to form a ball pattern.