Head stack flex assembly and base assembly for storage drive and method of assembly

A flexible printed circuit for a storage drive assembly is provided. The flexible printed circuit includes a stiffener layer having a first stiffener region, and a second stiffener region separated from the first stiffener region by a hinge region, a first insulation layer disposed on the stiffener layer, a conductive electrode layer disposed on the first insulation layer; and a second insulation layer disposed on the conductive electrode layer, wherein the hinge region is formed from the first insulation layer, the conductive electrode layer and the second insulation layer.

BACKGROUND

FIG. 1Aillustrates a perspective view of a head stack assembly10according to a related art configuration.FIGS. 1B and 1Cillustrate top and bottom perspective views of a motor base assembly12according to the related art configurations. As illustrated inFIG. 1A, an electrical connection between the head stack assembly10and a flexible printed circuit assembly14may be accomplished using a flex bracket16connected to the head stack assembly10by a dynamic loop18. In other words, the dynamic loop18connects the head stack assembly10to the flex bracket16, and the flexible printed circuit assembly14is attached to the flex bracket16. The flex bracket16also includes one or more mounting screw holes20passing there through, which can be used to attach the flex bracket16to the motor base assembly12.

As illustrated inFIGS. 1B and 1C, the motor base assembly12includes a bracket receiving area22having protrusion structures24with screw receiving holes26to which the mounting screw holes20of the flex bracket16can be aligned. The screw receiving holes26may pass completely through the motor base assembly12. The motor base assembly12may also include a window28passing through the motor base assembly12. The window28may allow electrical connection to the flexible printed circuit assembly14when the flex bracket16is mounted into the bracket receiving area22. Sometimes a gasket may also be provided between the flex bracket16and the motor base assembly12around the window28. However, the various components of the flex bracket16, mounting screws, and gasket may increase manufacturing costs. Further, the mounting screws may represent a contamination source, and reduce drive cleanliness.

DETAILED DESCRIPTION

The subject matter described herein is taught by way of example embodiments. Various details may be omitted for the sake of clarity and to avoid obscuring the subject matter described.

FIG. 2is an exploded, perspective view generally illustrating storage device100. Referring toFIG. 2, a storage device100is illustrated, according to one embodiment. The storage device100comprises a hub102, a media104physically contacting and supported by at least one mounting surface (not labeled) of the hub102, and a head106operable to write to and read from the media104. In one embodiment, the hub102comprises a substantially cylindrical portion108which defines a longitudinal axis L and a mounting surface substantially normal to the longitudinal axis L, the mounting surface extending radially outward.

As illustrated inFIG. 2, a storage device100comprises a magnetic disk drive, and the structures and methods described herein will be described in terms of such a disk drive. However, these structures and methods may also be applied to and/or implemented in other storage devices, including, e.g., solid-state hybrid drives (SSHD), optical and magneto-optical disk drives. Solid-state hybrid drives may additionally include non-volatile memory (e.g., flash).

The media104may comprise any of a variety of magnetic or optical disk media having a substantially concentric opening114defined there through. Of course, in other embodiments, the storage device100may include more or fewer disks. For example, the storage device100may include one disk or it may include two or more disks. The media104each include a disk surface116, as well as an opposing disk surface not visible inFIG. 1above. In one embodiment, the disk surfaces116comprise a plurality of generally concentric tracks for storing data.

As illustrated, the hub102may be coupled to and support the media104. The hub102may also be rotatably attached to a motor base assembly118of the storage device100, and may form one component of a motor120(e.g., a spindle motor). The motor120and the hub102may be configured to rotate the media104about the longitudinal axis L.

Further, a disk clamp may be coupled to the hub102to provide a downward clamping force to the media104. Specifically, the disk clamp may be positioned above the media104and attached to an upper surface of the hub102. The interaction of the disk clamp and the hub102provides downward clamping force.

The storage device100may further include a cover122, which, together with the motor base assembly118, may form a sealed enclosure to house the media104and the motor120. In some embodiments, the cover122may be attached to the motor base assembly118by a plurality of screws140.

The storage device100may also include a head stack assembly (“HSA”)124rotatably attached to the motor base assembly118. The HSA124may include an actuator126comprising an actuator body128and one or more actuator arms130extending from the actuator body128. The actuator body128may further be configured to rotate about an actuator pivot axis.

One or two head gimbal assemblies (“HGA”)132may be attached to a distal end of each actuator arm130. Each HGA132includes a head106operable to write to and read from a corresponding media104. The HSA124may further include a coil134through which a changing electrical current is passed during operation. The coil134interacts with one or more magnets136that are attached to the motor base assembly118to form a voice coil motor (“VCM”) for controllably rotating the HSA124.

The head106may comprise any of a variety of heads for writing to and reading from a media104. In magnetic recording applications, the head106may include an air bearing slider and a magnetic transducer that includes a writer and a read element. The magnetic transducer's writer may be of a longitudinal or perpendicular design, and the read element of the magnetic transducer may be inductive or magneto resistive. In optical and magneto-optical recording applications, the head106may include a mirror and an objective lens for focusing laser light on to an adjacent disk surface.

FIG. 3is a perspective view of a head stack assembly124according to an example implementation of the present application. As illustrated, the head stack assembly124is connected to a flexible printed circuit205by a dynamic loop210. The dynamic loop210provides electrical connection between the flexible printed circuit205and the head stack assembly124to allow signal transfer between the flexible printed circuit205in the head of the head stack assembly124. As discussed in greater detail below with respect toFIGS. 6A and 6B, the flexible printed circuit205may have a laminated structure.

FIG. 4is a first perspective view of a flexible printed circuit205for the head stack assembly124according to an example implementation of the present application showing top surfaces of the flexible printed circuit205.FIG. 5is a second perspective view of the flexible printed circuit205for a head stack assembly124according to an example implementation of the present application showing bottom surfaces of the flexible printed circuit205.

As illustrated, the flexible printed circuit205includes a first stiffener region215and a second stiffener region220connected by a hinge region225. The hinge region225may have greater flexibility than the first stiffener region215, and the second stiffener region220allows the hinge region225to bend such that the first stiffener region215and the second stiffener region220may move relative to each other.

The second stiffener region220may include a first plate section230which extends substantially parallel to the first stiffener region215. The second stiffener region220may also include a second plate section235that is angled with respect to the first plate section230. The second plate section235may connect the first plate section230with the dynamic loop region210.

The bottom surface of the first stiffener region215may include one or more contact pad regions250. In some example limitations, the contact pad regions250may be formed by an area of non-insulation that allows access to an internal electrode255located within the flexible printed circuit205. Further, in some example implementations, the first stiffener region215may also include alignment features240. For example, one or more holes, bumps, nodules, or other alignment features that may be apparent to a person of ordinary skill in the art may be formed on the first stiffener region215. As discussed in greater detail below, the alignment features240may be used to align the flexible printed circuit205with a motor base assembly.

FIGS. 6A and 6Bare enlarged views of the flexible printed circuit205according to an example implementation of the present application. Specifically,FIG. 6Aillustrates an enlarged view of the first stiffener region215of the flexible printed circuit illustrating a laminate structure600. As illustrated, the laminate structure600of the first stiffener region215includes a stiffener layer605. In some example implementations, the stiffener layer605may be formed from a rigid material that can provide support for the other layers in the laminate structure600. For example, the stiffener layer605may be formed from aluminum, stainless steel, or any other rigid material that may be apparent to a person of ordinary skill in the art.

The laminate structure600of the first stiffener region215may also include a first insulation layer610formed on the stiffener layer605, an electrically conductive layer615formed on the first insulation layer610, and a second insulation layer620formed on the electrically conductive layer615. The electrically conductive layer615may be formed from any electrically conductive material including but not limited to gold, zinc, silver, or any other material that may be apparent to a person of ordinary skill in the art.

Further, the first insulation layer610and the second insulation layer620may be formed from any electrically isolative material that may be apparent to a person of ordinary skill in the art. For example, the first insulation layer610and the second insulation layer620may be formed from silicon nitride, silicon oxide, or any other material that may be apparent to a person of ordinary skill in the art. Additionally, in some example of limitations, the second insulation layer620may include an area of non-insulation625that provides access to the electrically conductive layer615under the second insulation layer622to form the contact pad region250.

FIG. 6Billustrates an enlarged view of the second stiffener region220of the flexible printed circuit illustrating a laminate structure602. As illustrated, the laminate structure602of the second stiffener region220includes a stiffener layer630. In some example implementations, the stiffener layer630may be formed from a rigid material that can provide support for the other layers in the laminate structure600. For example, the stiffener layer630may be formed from aluminum, stainless steel, or any other rigid material that may be apparent to a person of ordinary skill in the art.

The laminate structure602of the second stiffener region220may also include a first insulation layer635formed on the stiffener layer630, an electrically conductive layer640formed on the first insulation layer635, and a second insulation layer645formed on the electrically conductive layer640. The electrically conductive layer640may be formed from any electrically conductive material including but not limited to gold, zinc, silver, or any other material that may be apparent to a person of ordinary skill in the art.

Further, the first insulation layer635and the second insulation layer645may be formed from any electrically isolative material that may be apparent to a person of ordinary skill in the art. For example, the first insulation layer635and the second insulation layer645may be formed from silicon nitride, silicon oxide, or any other material that may be apparent to a person of ordinary skill in the art.

FIG. 7is a first perspective view of a motor base assembly118according to an example implementation of the present application illustrating an upper surface of the motor base assembly118. Further,FIG. 8is a second perspective view of the motor base assembly118according to an example implementation of the present application illustrating a lower upper surface of the motor base assembly118. As illustrated, the motor base assembly118includes a basewall705(e.g., a floor) and a plurality of sidewalls710extending upward from the basewall705to define an interior700of the motor base assembly118. Further, within the interior700of the motor base assembly118, a stiffener support portion715is also formed.

The stiffener support portion715may include a stiffener guide slot720and a hole725adjacent the stiffener guide slot720. In some example implementations, the hole725may extend through the support portion715and the basewall705of the motor base assembly118. Further, in some example implementations the stiffener support portion715may also include a secondary plate slot730. Additionally, in some example implementations, the exterior of the base wall705may also include alignment features740and a land region735. The alignment features740may include one or more holes, bumps, nodules, or other alignment features that may be apparent to a person of ordinary skill in the art. As discussed in greater detail below, the alignment features740of the motor base assembly118may be used to align the flexible printed circuit205.

FIG. 9is a first perspective view of the motor base assembly118with a flexible printed circuit205installed according to an example of implementation of the present application illustrating an upper surface thereof. As illustrated, the second stiffener region220of the flexible printed circuit205has been installed in the support portion715of the basewall705. Specifically, the first plate section230is installed in the stiffener guide slot720and the second plate section235is installed in the secondary plate slot730. The dynamic loop210runs from an end of the second plate section235that extends out of the secondary plate slot730to connect the flexible printed circuit205to the head stack assembly124located within the interior700of the motor base assembly118.

FIG. 10is a second perspective view of the motor base assembly118with a flexible printed circuit205installed according to an example implementation of the present application illustrating a lower surface thereof. As illustrated, the first stiffener region215has been inserted through the hole725through the basewall705and the flexible printed circuit205has been bent along the hinge region225to position the first stiffener region215against the basewall705of the motor base assembly118. The first stiffener region215has been oriented such that contact regions250are directed away from the basewall705of the motor base assembly118. Such an orientation may allow access to the internal electrode255of the contact regions250from outside the motor base assembly118. Further, in some example implementations, the alignment features240of the first stiffener region215may be aligned with the alignment features740of the motor base assembly118.

FIG. 11is a first transparent perspective view of the motor base assembly118with a flexible printed circuit205installed according to an example implementation of the present application. Further,FIG. 12is a second transparent perspective view of the motor base assembly118with a flexible printed circuit205installed according to an example implementation of the present application. Again, the second stiffener region220of the flexible printed circuit205is illustrated installed in the support portion715of the base wall705. Specifically, the first plate section230is installed in the stiffener guide slot720and the second plate section235is installed in the secondary plate slot730. The dynamic loop210runs from an end of the second plate section235that extends out of the secondary plate slot730to connect the flexible printed circuit205to the head stack assembly124located within the interior700of the motor base assembly118.

Further, the first stiffener region215has been inserted through the hole725through the basewall705and the flexible printed circuit205has been bent along the hinge region225to position the first stiffener region215against the basewall705of the motor base assembly118. The first stiffener region215has been oriented such that contact regions250are directed away from the basewall705of the motor base assembly118. Such an orientation may allow access to the internal electrode255of the contact regions250from outside the motor base assembly118. Further, in some example implementations, the alignment features240of the first stiffener region215may be aligned with the alignment features740of the motor base assembly118.

FIG. 13is bottom view of the motor base assembly118with an adhesive seal1305installed over a portion of the flexible printed circuit205. As illustrated the seal1305may be installed over the first stiffener region215of the flexible printed circuit205and is attached to the land region735of the motor base assembly118. In some example implementations, the seal1305may hermetically seal the motor base assembly118. The seal1305may also attach flexible printed circuit205and may also form a hermetic seal therewith. The seal1305may be a self-adhesive seal, or may be attached using an applied adhesive or other sealing compound (e.g., glue, epoxy, solder, welding compound or any other sealing compound relevant to a person of ordinary skill in the art) between the seal1305and the land region735of the motor base assembly118.

In some example implementations, the seal1305may include a window1310that provides access to portions of the first stiffener region215of the flexible printed circuit205. As illustrated, the internal electrodes255of the contact pad regions250are accessible through the window1310of the seal1305. Such a configuration may allow access to the internal electrode255of the contact regions250from outside the motor base assembly118.

FIG. 14is a flowchart for a process1400of manufacturing a flexible printed circuit according to an example implementation of the present application. For simplicity, some steps may be omitted, interleaved, and/or combined. The process1400may be used to manufacture an example implementation of a flexible printed circuit205discussed above. Further, the process1400may also be used to fabricate multiple flexible printed circuits205at substantially the same time. The process1400may also be used to fabricate other flexible printed circuits, as may be apparent to a person of ordinary skill in the art. The method500is also described in the context of particular layers. A particular layer may include multiple materials and/or multiple sub-layers.

In1405, a stiffener layer605,630is formed. The stiffener layer605,630may be formed from metal (e.g., aluminum, nickel, iron, or other metallic material), ceramic, or any other stiffening material that may be apparent to a person of ordinary skill in the art. Further, the forming process of the stiffener layer605,630is not particularly limited and may include any process that may be apparent to a person of ordinary skill in the art including deposition, sputtering or any other known process that may be apparent.

Further, in1410, a first insulation layer610,635is formed on the stiffener layer605,630. The first insulation layer610,635may be formed from a non-conductive material including a ceramic material, polymer material, or other non-metallic material that may be apparent to a person of ordinary skill in the art. For example, the non-conductive material may be silicon nitride, silicon oxide, or any other material that may be apparent to a person of ordinary skill in the art. Further, the forming process of the first insulation layer610,635is not particularly limited and may include any process that may be apparent to a person of ordinary skill in the art including deposition, sputtering or any other known process that may be apparent.

In1415, an electrically conductive layer615,640is formed on the first insulation layer610,635. The electrically conductive layer615,640may be formed from a conductive material including a metallic material, or any other material that may be apparent to a person of ordinary skill in the art. For example, the conductive material may be gold, aluminum, silver, zinc, or any other material that may be apparent to a person of ordinary skill in the art. Further, the forming process of the electrically conductive layer615,640is not particularly limited and may include any process that may be apparent to a person of ordinary skill in the art including deposition, sputtering or any other known process that may be apparent.

Further, in1420, a second insulation layer620,645is formed on the conductive layer615,640. The second insulation layer620,645may be formed from a non-conductive material including a ceramic material, polymer material, or other non-metallic material that may be apparent to a person of ordinary skill in the art. For example, the non-conductive material may be silicon nitride, silicon oxide, or any other material that may be apparent to a person of ordinary skill in the art. Further, the forming process of the second insulation layer620,645is not particularly limited and may include any process that may be apparent to a person of ordinary skill in the art including deposition, sputtering or any other known process that may be apparent.

Further, in some example implementations, the forming of the second insulation layer620,645may also include an etching process to expose a portion of the electrically conductive layer615,640beneath the second insulation layer620,645to form a contact pad region250. The etching process is not particularly limited and may include a wet etch, a dry etch, or any other material removing process that may be apparent to a person of ordinary skill in the art.

After the second insulation layer620,645is formed, a hinge region225is formed to separate the stiffener layer605,630into first and second stiffener regions215,220in1425. The forming of the hinge region225may include an etching process or any other material removal process to remove the stiffener region605,630from a region of the flexible printed circuit205while leaving the remaining layers (e.g., the first and second insulation layers610,620,635,645and the electrically conductive layer615,640). The process used to form the hinge region225is not particularly limited and may include a wet etch, a dry etch, or any other material removing process that may be apparent to a person of ordinary skill in the art.

Further, a dynamic loop region210may be formed at one end of the second stiffener regions215,220in1430. The forming of the dynamic loop region210may also include an etching process or any other material removal process to remove the stiffener region605,630from a region at one end of the second stiffener region215,220of the flexible printed circuit205while leaving the remaining layers (e.g., the first and second insulation layers610,620,635,645and the electrically conductive layer615,640). The process used to form dynamic loop region210is not particularly limited and may include a wet etch, a dry etch, or any other material removing process that may be apparent to a person of ordinary skill in the art. After the dynamic loop region is formed, the process1400may end.

FIG. 15is a flowchart for a process1500of assembling a storage drive assembly according to an example implementation of the present application. The process1500may be used to form a storage drive assembly100and components thereof illustrated inFIGS. 2-13discussed above. In the process1500, a flexible printed circuit (e.g., flexible printed circuit205discussed above) may be installed in a motor base assembly (e.g., motor base assembly118discussed above.

At1505, a first stiffener region215of the flexible printed circuit205may be inserted into a stiffener guide slot720of a stiffener support portion715of the motor base assembly118. In some example implementations, the insertion of the first stiffener region215into the stiffener guide slot720may be manually performed by a human. In other example implementations, the insertion of the first stiffener region215may be assisted or completely performed by a computer controlled placement device (e.g., a user controlled or fully automated assembly robot or other device that may be apparent to a person of ordinary skill in the art). Further, the insertion of the first stiffener region215may also be assisted by a computer vision system in some example implementations.

Further at1510, the first stiffener region215of the flexible printed circuit205may be inserted through a hole725through the basewall705of the motor base assembly118adjacent the stiffener guide slot720. In some example implementations, the insertion of the first stiffener region215through the hole725may be manually performed by a human. In other example implementations, the insertion of the first stiffener region215may be assisted or completely performed by a computer controlled placement device (e.g., a user controlled or fully automated assembly robot or other device that may be apparent to a person of ordinary skill in the art.) Further, the insertion of the first stiffener region215may also be assisted by a computer vision system in some example implementations.

Additionally at1515, a second stiffener region220of the flexible printed circuit205may be inserted into the stiffener guide slot720of the stiffener support portion715of the motor base assembly118. In some example implementations, the insertion of the second stiffener region220into the stiffener guide slot720may be manually performed by a human. In other example implementations, the insertion of the second stiffener region220may be assisted or completely performed by a computer controlled placement device (e.g., a user controlled or fully automated assembly robot or other device that may be apparent to a person of ordinary skill in the art). Further, the insertion of the second stiffener region220may also be assisted by a computer vision system in some example implementations.

In some example implementations, the insertion of the second stiffener region220into the stiffener guide slot720may include inserting a first plate section230of the second stiffener region220into the stiffener guide slot720and inserting a second plate section235into a secondary plate slot730adjacent the stiffener guide slot720. Again, in some example implementations, the insertion of the first plate section230of the second stiffener region220into the stiffener guide slot720and the insertion of the a second plate section235into the secondary plate slot730may be manually performed by a human. In other example implementations, the insertion of the first plate section230of the second stiffener region220into the stiffener guide slot720and the insertion of the a second plate section235into the secondary plate slot730may be assisted or completely performed by a computer controlled placement device (e.g., a user controlled or fully automated assembly robot or other device that may be apparent to a person of ordinary skill in the art.) Further, the insertion of the first plate section230of the second stiffener region220into the stiffener guide slot720and the insertion of the a second plate section235into the secondary plate slot730may also be assisted by a computer vision system in some example implementations.

After the insertion of the second stiffener region220, the flexible printed circuit205may be bent along a hinge region225such that the first stiffener region215extends substantially parallel to a basewall705of the motor base assembly118at1520. In some example implementations, the bending of the flexible printed circuit205along the hinge region225may be manually performed by a human. In other example implementations, the bending of the flexible printed circuit205along the hinge region225may be assisted or completely performed by a computer controlled manipulation device (e.g., a user controlled or fully automated assembly robot or other device that may be apparent to a person of ordinary skill in the art). Further, the bending of the flexible printed circuit205along the hinge region225may also be assisted by a computer vision system in some example implementations.

In some example implementations, the bending of the flexible printed circuit205along the hinge region225may include aligning alignment features240formed on the first stiffener region215with alignment features740formed on the motor base assembly118. The aligning the alignment features240formed on the first stiffener region215with alignment features740formed on the motor base assembly118may be manually performed by a human eye in some example implementations. In some implementations, the aligning the alignment features240formed on the first stiffener region215with alignment features740formed on the motor base assembly118may be assisted or completely performed by a computer vision system.

Further at1525, the first stiffener region215may be sealed to the motor base assembly118. The sealing of the first stiffener region215may form a hermetic seal in some example implementations. In some example implementations, the sealing of the first stiffener region215to the motor base assembly118may performed by applying a liquid, semi-liquid or gelatinous sealing agent (e.g., an adhesive, a liquid gasket, or any other sealing agent that may be apparent to a person of ordinary skill in the art). In other example implementations, the sealing of the first stiffener region215to the motor base assembly118may be performed by applying a solid seal (e.g., a self-adhesive seal or gasket, a seal or gasket with separate adhesive, or any other seal device that may be apparent to a person of ordinary skill in the art) over the first stiffener region215.

In some example implementations, the sealing of the first stiffener region215may be manually performed by a human. In other example implementations, the sealing of the first stiffener region215may be assisted or completely performed by a computer controlled manipulation device (e.g., a user controlled or fully automated assembly robot or other device that may be apparent to a person of ordinary skill in the art). Further, the sealing of the first stiffener region215may also be assisted by a computer vision system in some example implementations. Once the first stiffener region215is sealed to the motor base assembly118, the process1500may end.

The foregoing detailed description has set forth various implementations of the devices and/or processes via the use of block diagrams, schematics, and examples. Insofar as such block diagrams, schematics, and examples contain one or more functions and/or operations, each function and/or operation within such block diagrams, flowcharts, or examples can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof.