Single-pole recording head having trapezoidal main pole and bevel angle promotion layer and methods of fabricating the same

#This invention relates to single-pole recording heads for disk drives and in particular to a structure and method for reducing cross-talk and improving the signal-to noise ratio in a head used for perpendicular recording on a magnetic disk.

#In perpendicular magnetic recording the data is recorded on a magnetic disk in which the easy axis of magnetization is aligned perpendicular to the surface of the disk. The recording head, viewed from the air bearing surface, contains a relatively small main pole and a relatively large auxiliary pole.

#The recording head is normally mounted on a rotary arm which pivots about a stationary axis to move the head to various radial positions on the disk. This generates a skew angle θ between the main axis of the rotary arm and the tangential direction of the data tracks on the disk. This is illustrated schematically in FIGS. 1A-1C. In FIG. 1A the skew angle θ is equal to zero, i.e., the main axis of rotary arm 2 is exactly parallel to the data track on disk 4 that underlies the recording head 3 at the end of rotary arm 2. In FIG. 1B, where the recording had 3 is located nearer to the center of disk 4, the skew angle is equal to θ1. In FIG. 1C, where recording head 3 is located nearer to the edge of disk 4, the skew angle is equal to θ2 (which would have a sign opposite to that of θ1).

#FIGS. 1A-1C illustrate how a skew angle is produced as a recording head mounted to a rotary arm sweeps across a magnetic disk.

#FIGS. 2A and 2B illustrate how cross talk can be reduced and the signal-to-noise ratio improved by forming the main pole of a recording head in a trapezoidal shape.

#FIG. 3 is a schematic view from the ABS of a single pole type recording head having a trapezoidal main pole.

#As described above, the presence of a hard alumina level directly beneath the main pole impedes the fabrication of a large bevel angle α using an ion milling process. One technique of overcoming this problem is to fabricate a relatively soft layer, which can be referred to as a “bevel angle promotion layer” or simply “promotion layer,” immediately below the main pole. FIG. 7 illustrates a view similar to that of FIG. 6 but with a promotion layer 20 underneath main pole 11.

#The promotion layer 11 may be fabricated by the process illustrated in FIGS. 8A-8C. Initially, the yoke 15 and underlying alumina layer are fabricated using known processes. Then, as shown in FIG. 8A, a “lift off” photoresist layer 22 is deposited and patterned with an aperture overlying a portion of yoke 15. A “lift” off photoresist layer is actually two photoresist layers which are patterned to produce the overhang shown in FIG. 8A.

#Next, as shown in FIG. 8B, promotion layer 20 is deposited on the structure. Promotion layer 20 could include NiP, Rh, Ta, NiCr or Cd, for example. Lift off photoresist layer 22 is then removed (along with the overlying portion of promotion layer 20), and main pole 11 is deposited. Main pole 11 could be made of NiFe. Afterward, the overlying alumina layer is deposited, and the structure is lapped or polished to the location of the ABS (shown in FIGS. 8B and 8C), producing the head shown in FIG. 7.