Microactuator, head gimbal assembly, and disk drive device
View Patent ↗Embodiments of the present invention relate to approaches to effectively let noise on a head slider bonded to a silicon substrate of a microactuator, escape to the ground. A head gimbal assembly (HGA) according to an embodiment of the present invention comprises a microactuator bonded to a gimbal tongue. The microactuator comprises a piezoelectric element and a movable part for moving in response to expansion or contraction of the piezoelectric element. The motion of the movable part causes a head slider to slightly move. The microactuator further comprises a conductive path including an impurity-containing silicon layer formed on the silicon substrate. The conductive path transmits electric charge of the head slider to a suspension. The conductivity of the impurity-containing silicon layer is lower than the one of the silicon substrate so that the noise charge of the head slider may escape to the suspension.
1. A head gimbal assembly comprising:
a suspension;
a silicon substrate bonded to the suspension and having a movable part and a stationary part;
a piezoelectric element bonded to the silicon substrate;
a head slider bonded to the movable part;
a conductive path formed on the silicon substrate and having conductivity higher than the silicon substrate and for transmitting electric charge of the head slider; and
a conductive stud formed on the suspension and being in contact with the conductive path on a side of the suspension reverse to a head slider mounting surface on which the head slider is mounted.
2. The head gimbal assembly according to claim 1 , wherein the conductive path comprises an impurity-containing silicon layer.
3. The head gimbal assembly according to claim 1 , wherein the conductive path comprises a penetrating path extending from the head slider mounting surface to the reverse side through the silicon substrate.
4. The head gimbal assembly according to claim 3 , wherein
the silicon substrate comprises a through-hole; and
the penetrating path penetrates the through-hole.
5. The head gimbal assembly according to claim 4 , wherein the penetrating path comprises a metallic layer deposited inside the through-hole.
6. The head gimbal assembly according to claim 4 , wherein the penetrating path comprises an impurity-containing silicon layer provided on the inner surface of the through-hole.
7. The head gimbal assembly according to claim 4 , wherein the through-hole is provided in the stationary part.
8. The head gimbal assembly according to claim 2 , wherein the conductive path comprises an impurity-containing silicon layer extending from the movable part to the stationary part on the slider mounting surface.
9. The head gimbal assembly according to claim 3 , wherein the conductive path comprises an impurity-containing silicon layer extending and joining to the penetrating path on the slider mounting surface.
10. The head gimbal assembly according to claim 3 , wherein
the silicon substrate comprises a plurality of through-holes; and
the conductive path comprises penetrating paths passing through the plurality of through-holes, respectively.
11. A microactuator comprising:
a silicon substrate having a stationary part to be bonded to a suspension and a movable part to be bonded to a head slider;
a piezoelectric element fixed on the silicon substrate for moving the movable part;
a conductive path formed on the silicon substrate, the conductive path having conductivity higher than the silicon substrate, and extending from a head slider mounting surface on which the head slider is mounted to the reverse side thereto.
12. A disk drive device comprising:
an enclosure;
a motor mounted in the enclosure for spinning a disk;
a head slider for accessing the disk; and
an actuator for supporting the head slider and moving the head slider over the disk in a radial direction thereof, wherein the actuator comprises,
a suspension having a conductive stud, and
a microactuator having a head slider mounting surface on which the head slider is mounted and fixed to the suspension in contact with the conductive stud on a side reverse to the head slider mounting surface, and the microactuator further comprises,
a silicon substrate including a movable part to which the head slider is bonded, and a stationary part bonded to the suspension in contact with the conductive stud;
a piezoelectric element bonded to the silicon substrate and for moving the movable part; and
a conductive path formed on the silicon substrate and having conductivity higher than the silicon substrate for transmitting electric charge of the head slider.
13. The disk drive device according to claim 12 , wherein the conductive path comprises an impurity-containing silicon layer.
14. The disk drive device according to claim 12 , wherein the conductive path comprises a penetrating path extending from the head slider mounting surface to the reverse side through the silicon substrate.
15. The disk drive device according to claim 14 , wherein
the silicon substrate comprises a through-hole; and
the penetrating path penetrates the through-hole.
16. The disk drive device according to claim 15 , wherein the penetrating path comprises a metallic layer deposited inside the through-hole.
17. The disk drive device according to claim 15 , wherein the penetrating path comprises an impurity-containing silicon layer provided on the inner surface of the through-hole.
18. The disk drive device according to claim 15 , wherein the through-hole is provided in the stationary part.
19. The disk drive device according to claim 13 , wherein the conductive path comprises an impurity-containing silicon layer extending from the movable part to the stationary part on the slider mounting surface.
20. The disk drive device assembly according to claim 14 , wherein the conductive path comprises an impurity-containing silicon layer extending and joining to the penetrating path on the slider mounting surface.