Disk drive head stack assembly having a flexible printed circuit with heat transfer limiting features
View Patent ↗A head stack assembly (HSA) for a disk drive includes an actuator body, at least one actuator arm extending from the actuator body, and a flexible printed circuit (FPC). The FPC includes first and second pluralities of electrically conductive FPC traces, each having a distal portion that terminates at a respective one of a plurality of FPC bond pads. The HSA also includes a head gimbal assembly (HGA) having a laminate flexure with a plurality of electrically conductive flexure bond pads that are bonded to the plurality of FPC bond pads. A width of at least one of the first plurality of FPC traces is greater than a width of at least one of the second plurality of FPC traces. The distal portion of at least one of the first plurality FPC traces includes a first opening therethrough, for example less than 1 mm from its corresponding FPC bond pad.
1. A disk drive comprising:
a disk drive base;
a disk rotably mounted to the disk drive base;
a head stack assembly (HSA) rotably mounted to the disk drive base, the HSA including an actuator body, at least one actuator arm extending from the actuator body, and a flexible printed circuit (FPC), the FPC including
a first plurality of FPC traces, each being electrically conductive and having a distal portion that terminates at a respective one of a first plurality of FPC bond pads that are electrically conductive;
a second plurality of FPC traces, each being electrically conductive and terminating at a respective one of a second plurality of FPC bond pads that are electrically conductive, wherein a first width of at least one of the first plurality of FPC traces is greater than a second width of at least one of the second plurality of FPC traces;
wherein the distal portion of the at least one of the first plurality FPC traces includes a first opening therethrough; and
at least one head gimbal assembly comprising
a read head; and
a suspension assembly attached to the at least one actuator arm, the suspension assembly comprising
a load beam, and
a laminate flexure that includes a plurality of electrically conductive flexure traces that each terminate at a respective one of a plurality of electrically conductive flexure bond pads, the plurality of electrically conductive flexure bond pads being bonded to the first and second pluralities of FPC bond pads.
2. The disk drive of claim 1 wherein the first opening spans at least 30% of the first width.
3. The disk drive of claim 1 wherein the first width is in the range 100 microns to 300 microns, and the first opening spans at least 30 microns of the first width, but no more than 260 microns of the first width.
4. The disk drive of claim 1 wherein the plurality of electrically conductive flexure bond pads is bonded to the first and second pluralities of FPC bond pads by an anisotropic conductive film.
5. The disk drive of claim 1 wherein the distal portion of the at least one of the first plurality FPC traces includes a plurality of openings therethrough that includes the first opening.
6. The disk drive of claim 1 wherein the first opening is disposed immediately adjacent the respective one of the first plurality of FPC bond pads.
7. The disk drive of claim 1 wherein the first opening is disposed a first distance from the respective one of the first plurality of FPC bond pads, the first distance being measured along the at least one of the first plurality FPC traces, the first distance not exceeding five times the first width.
8. The disk drive of claim 7 wherein the first distance is less than 1 mm.
9. The disk drive of claim 1 wherein the FPC further comprises a metallic stiffener and a FPC dielectric layer between the metallic stiffener and the first and second pluralities of FPC traces, the metallic stiffener including a first window therethrough, the first window overlying a first portion of the first plurality of FPC traces but not overlying any portion of the second plurality of FPC traces.
10. The disk drive of claim 9 wherein the metallic stiffener further includes a second window therethrough, the second window overlying a second portion of the first plurality of FPC traces but not overlying any portion of the second plurality of FPC traces.
11. The disk drive of claim 9 wherein the actuator body and the metallic stiffener each comprises aluminum, and are in contact with each other.
12. The disk drive of claim 9 wherein the FPC further comprises an insulative cover layer over the first and second pluralities of FPC traces, the insulative cover layer being not disposed between the metallic stiffener and the first or second pluralities of FPC traces.
13. The disk drive of claim 1 wherein the plurality of electrically conductive flexure traces, and the first and second pluralities of FPC traces, each comprises copper.
14. The disk drive of claim 1 wherein the plurality of electrically conductive flexure bond pads, and the first and second pluralities of FPC bond pads, each comprises copper with a gold coating.
15. A head stack assembly (HSA) for a disk drive, the HSA comprising:
an actuator body, at least one actuator arm extending from the actuator body, and a flexible printed circuit (FPC), the FPC including
a first plurality of FPC traces, each being electrically conductive and having a distal portion that terminates at a respective one of a first plurality of FPC bond pads that are electrically conductive;
a second plurality of FPC traces, each being electrically conductive and terminating at a respective one of a second plurality of FPC bond pads that are electrically conductive, wherein a first width of at least one of the first plurality of FPC traces is greater than a second width of at least one of the second plurality of FPC traces;
wherein the distal portion of the at least one of the first plurality FPC traces includes a first opening therethrough; and
at least one head gimbal assembly comprising
a read head; and
a suspension assembly attached to the at least one actuator arm, the suspension assembly comprising
a load beam, and
a laminate flexure that includes a plurality of electrically conductive flexure traces that each terminate at a respective one of a plurality of electrically conductive flexure bond pads, the plurality of electrically conductive flexure bond pads being bonded to the first and second pluralities of FPC bond pads.
16. The HSA of claim 15 wherein the first opening spans at least 30% of the first width.
17. The HSA of claim 15 wherein the first width is in the range 100 microns to 300 microns, and the first opening spans at least 30 microns of the first width, but no more than 260 microns of the first width.
18. The HSA of claim 15 wherein the plurality of electrically conductive flexure bond pads is bonded to the first and second pluralities of FPC bond pads by an anisotropic conductive film.
19. The HSA of claim 15 wherein the distal portion of the at least one of the first plurality FPC traces includes a plurality of openings therethrough that includes the first opening.
20. The HSA of claim 15 wherein the first opening is disposed immediately adjacent the respective one of the first plurality of FPC bond pads.
21. The HSA of claim 15 wherein the first opening is disposed a first distance from the respective one of the first plurality of FPC bond pads, the first distance being measured along the at least one of the first plurality FPC traces, the first distance not exceeding five times the first width.
22. The HSA of claim 21 wherein the first distance is less than 1 mm.
23. The HSA of claim 15 wherein the FPC further comprises a metallic stiffener and a FPC dielectric layer between the metallic stiffener and the first and second pluralities of FPC traces, the metallic stiffener including a first window therethrough, the first window overlying a first portion of the first plurality of FPC traces but not overlying any portion of the second plurality of FPC traces.
24. The HSA of claim 23 wherein the FPC further comprises an insulative cover layer over the first and second pluralities of FPC traces, the insulative cover layer being not disposed between the metallic stiffener and the first or second pluralities of FPC traces.
25. A disk drive comprising:
a disk drive base;
a disk rotably mounted to the disk drive base;
a head stack assembly (HSA) rotably mounted to the disk drive base, the HSA including an actuator body, at least one actuator arm extending from the actuator body, and a flexible printed circuit (FPC), the FPC including
a first plurality of FPC traces, each being electrically conductive and having a distal portion that terminates at a respective one of a first plurality of FPC bond pads that are electrically conductive;
a second plurality of FPC traces, each being electrically conductive and terminating at a respective one of a second plurality of FPC bond pads that are electrically conductive, wherein a first width of at least one of the first plurality of FPC traces is greater than a second width of at least one of the second plurality of FPC traces;
a metallic stiffener including a first window therethrough, the first window overlying a first portion of the first plurality of FPC traces but not overlying any portion of the second plurality of FPC traces;
a FPC dielectric layer between the metallic stiffener and the first and second pluralities of FPC traces; and
at least one head gimbal assembly comprising
a read head; and
a suspension assembly attached to the at least one actuator arm, the suspension assembly comprising
a load beam, and
a laminate flexure that includes a plurality of electrically conductive flexure traces that each terminate at a respective one of a plurality of electrically conductive flexure bond pads, the plurality of electrically conductive flexure bond pads being bonded to the first and second pluralities of FPC bond pads.
26. The disk drive of claim 25 wherein the plurality of electrically conductive flexure bond pads is bonded to the first and second pluralities of FPC bond pads by an anisotropic conductive film.
27. The disk drive of claim 25 wherein the metallic stiffener further includes a second window therethrough, the second window overlying a second portion of the first plurality of FPC traces but not overlying any portion of the second plurality of FPC traces.
28. The disk drive of claim 25 wherein the actuator body and the metallic stiffener each comprises aluminum, and are in contact with each other.
29. The disk drive of claim 25 wherein the FPC further comprises an insulative cover layer over the first and second pluralities of FPC traces, the insulative cover layer being not disposed between the metallic stiffener and the first or second pluralities of FPC traces.