Patent ID: 8871102

Claim:
A method for forming a structure in a magnetic recording head from at least one layer corresponding to the structure, the method comprising: providing a first hard mask layer on the at least one layer; providing a second hard mask layer on the first hard mask layer; providing a bottom antireflective coating (BARC) layer on the second hard mask layer; providing a photoresist mask having a pattern on the second hard mask layer, the pattern including a line corresponding to the structure; transferring the pattern to the BARC layer and the second hard mask layer in a single etch using a first etch chemistry, the step of transferring the pattern being a vertical anisotropic etch; trimming at least the second hard mask layer, the photoresist mask and the BARC layer using a second etch chemistry substantially the same as the first etch chemistry to provide a mask including a hard mask line corresponding to the line and having a width of less than thirty nanometers, the hard mask line including a remaining portion of the second hard mask layer, the step of trimming being a horizontal anisotropic etch configured to remove material in a direction substantially perpendicular to the vertical anisotropic etch; transferring the pattern of the second hard mask including the hard mask line to the first hard mask layer after the step of trimming the at least the second hard mask layer, a remaining portion of the photoresist mask being consumed during the step of transferring the pattern; and transferring the pattern of the first hard mask layer to the at least one layer such that the structure substantially has the width.