Asymmetrical air bearing surface for a head slider in hard disk drives
View Patent ↗A method and apparatus for a head slider air bearing surface (ABS) in hard disk drives that mitigate fly height deviations. The invention mitigates these problems by providing an ABS of the head slider with elongated asymmetrical features that extend substantially parallel to the direction of the airflow caused by the rotating magnetic disk, in one or both of the inner diameter (ID) and outer diameter (OD) positions of the head slider with respect to the magnetic disk. The head slider may be produced with a two step etch process, as opposed to a three step etch process. By reducing the number of etching steps, the head slider of the invention can be produced at lower costs and in less time as fewer masks and chamber pump-down steps are required.
1. A head slider for a hard disk drive, the head slider comprising:
a leading edge;
a trailing edge;
first and second side edges extending between the leading edge and the trailing edge; and
an air bearing surface (ABS), comprising:
a trailing pad adjacent the trailing edge of the head slider;
a first arm having a first end connected to the trailing pad, the first arm extending from the trailing pad toward the leading edge of the head slider and including a first extended linear portion oriented substantially parallel to an airflow direction when the head slider is positioned at an inner diameter (ID) position relative to a spinning magnetic disk; and
a second arm having a first end connected to the trailing pad, the second arm extending from the trailing pad toward the leading edge of the head slider and including a second extended linear portion oriented substantially parallel to an airflow direction when the head slider is positioned at an outer diameter (OD) position relative to the spinning magnetic disk; wherein:
the entire second extended linear portion and at least part of the first extended linear portion are located on a same side of a center line of the ABS.
2. The head slider of claim 1 wherein:
the second arm includes a third extended linear portion;
the first extended linear portion of the first arm and the third extended linear portion of the second arm form a channel therebetween; and
the first and third extended linear portions and the channel are all substantially parallel to the airflow direction when the head slider is positioned at the ID position.
3. The head slider of claim 2 wherein most of the first and third extended linear portions and the channel are on the same side of the center line of the ABS as the second extended linear portion.
4. The head slider of claim 1 wherein:
the ABS further comprises first and second side pads adjacent to the first and second side edges of the slider, respectively;
the first arm has a distal end connected to the first side pad; and
the second arm has a distal end connected to the second side pad.
5. The head slider of claim 1 wherein the trailing pad is located at the center line of the ABS.
6. The head slider of claim 1 wherein the ABS further comprises a third arm between the first and second arm, the third arm having a first end connected to the trailing pad.
7. The head slider of claim 6 wherein the third arm has a distal end, the distal end of the third arm being located on the same side of the center line of the ABS as the second extended linear portion.
8. A hard disk drive, the hard disk drive comprising:
a magnetic disk with a surface, the magnetic disc creating an airflow in a direction substantially tangential to the magnetic disk, when the disk is spinning, and
an actuator arm designed and configured to support a head slider over the disk surface at an inner diameter (ID) position, an outer diameter (OD) position and positions in between the ID and OD positions, the head slider comprising:
a leading edge;
a trailing edge;
first and second side edges extending between the leading edge and the trailing edge; and
an air bearing surface (ABS), comprising:
a trailing pad adjacent the trailing edge of the head slider;
a first arm having a first end connected to the trailing pad, the first arm extending from the trailing pad toward the leading edge of the head slider and including a first extended linear portion oriented substantially parallel to an airflow direction when the head slider is positioned at an inner diameter (ID) position relative to a spinning magnetic disk; and
a second arm having a first end connected to the trailing pad, the second arm extending from the trailing pad toward the leading edge of the head slider and including a second extended linear portion oriented substantially parallel to an airflow direction when the head slider is positioned at an outer diameter (OD) position relative to the spinning magnetic disk; wherein:
the entire second extended linear portion and at least part of the first extended linear portion are located on a same side of a center line of the ABS.
9. The hard disk drive of claim 8 wherein:
the second arm includes a third extended linear portion;
the first extended linear portion of the first arm and the third extended linear portion of the second arm form a channel therebetween; and
the first and third extended linear portions and the channel are all substantially parallel to the airflow direction when the head slider is positioned at the ID position.
10. The hard disk drive of claim 9 wherein most of the first and third extended linear portions and the channel are on the same side of the center line of the ABS as the second extended linear portion.
11. The hard disk drive of claim 8 wherein:
the ABS further comprises first and second side pads adjacent to the first and second side edges of the slider, respectively;
the first arm has a distal end connected to the first side pad; and
the second arm has a distal end connected to the second side pad.
12. The hard disk drive of claim 8 wherein the trailing pad is located at the center line of the ABS.
13. The hard disk drive of claim 8 wherein the ABS further comprises a third arm between the first and second arm, the third arm having a first end connected to the trailing pad.
14. The hard disk drive of claim 13 wherein the third arm has a distal end, the distal end of the third arm being located on the same side of the center line of the ABS as the second extended linear portion.
15. A method of forming an air bearing surface (ABS) of a head slider for use in a hard disk drive, the method comprising:
providing a head slider having a leading edge, a trailing edge and first and second side edges;
conducting a first selective etch process on the head slider to form first and intermediate features at a first etch depth; and
conducting a second selective etch process on the head slider to form second features at a second etch depth, and to form third features at a third etch depth by subjecting the intermediate features formed by the first selective etch process to the second selective etch process; the first and second selective etch processes forming:
a trailing pad adjacent the trailing edge of the head slider;
a first arm having a first end connected to the trailing pad, the first arm extending from the trailing pad toward the leading edge of the head slider and including a first extended linear portion oriented substantially parallel to an airflow direction when the head slider is positioned at an inner diameter (ID) position relative to a spinning magnetic disk; and
a second arm having a first end connected to the trailing pad, the second arm extending from the trailing pad toward the leading edge of the head slider and including a second extended linear portion oriented substantially parallel to an airflow direction when the head slider is positioned at an outer diameter (OD) position relative to the spinning magnetic disk; wherein:
the entire second extended linear portion and at least part of the first extended linear portion are located on a same side of a center line of the ABS.
16. The method of claim 15 wherein the first and second selective etch processes form the second arm such that it includes a third extended linear portion; wherein
the first extended linear portion of the first arm and the third extended linear portion of the second arm form a channel therebetween; and
the first and third extended linear portions and the channel are all substantially parallel to the airflow direction when the head slider is positioned at the ID position.
17. The method of claim 16 wherein most of the first and third extended linear portions and the channel are on the same side of the center line of the ABS as the second extended linear portion.
18. The method of claim 15 wherein:
the first and second selective etch processes further form first and second side pads adjacent to the first and second side edges of the head slider, respectively;
the first arm has a distal end connected to the first side pad; and
the second arm has a distal end connected to the second side pad.
19. The method of claim 15 wherein all of the second arm is located on the same side of the center line of the ABS as the second extended linear portion.
20. The method of claim 15 wherein the first and second selective etch processes further form a third arm between the first and second arm, the third arm having a first end connected to the trailing pad.
21. The method of claim 20 wherein the third arm has a distal end, the distal end of the third arm being located on the same side of the center line of the ABS as the second extended linear portion.