Patent Application
20110132879
This application claims priority from the Japanese Patent Application No. 2009-278859, filed Dec. 8, 2009, the disclosure of which is incorporated herein in its entirety by reference.
Typically, to enable reflow of a solder ball positioned between two connecting parts, the solder ball is positioned precisely between the parts. However, if the parts are very small it is difficult to properly position the solder ball. Moreover, it is common for the solder ball to roll during the reflow process. The solder ball thus has to be frequently repositioned, resulting in a loss of manufacturing efficiency.
The drawings referred to in this description should be understood as not being drawn to scale except if specifically noted.
Reference will now be made in detail to embodiments of the present technology, examples of which are illustrated in the accompanying drawings. While the technology will be described in conjunction with various embodiment(s), it will be understood that they are not intended to limit the present technology to these embodiments. On the contrary, the present technology is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the various embodiments as defined by the appended claims.
Furthermore, in the following description of embodiments, numerous specific details are set forth in order to provide a thorough understanding of the present technology. However, the present technology may be practiced without these specific details. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the present embodiments.
Various types of device which uses media such as optical discs, magnetic disks or opto-magnetic disks are available as data storage devices. Amongst these, hard disk drives (HDD) have become widely used as storage devices for computers. Nor is the use of HDDs limited to computers, as they are also now used in image recording and playback devices, car navigation systems, digital cameras and the like.
HDDs are provided with a head slider which accesses the magnetic disk and an actuator which retains the head slider and moves the head slider over the magnetic disk by oscillation. The actuator has a suspension, the head slider being fixed to this suspension. The head slider is able to float above the magnetic disk due to the balance between viscosity of the air flowing between the head slider and the rotating magnetic disk and the force applied to the head slider by the suspension.
In one embodiment, there is a method of manufacture for a head gimbal assembly. This method transports a piece of metal to the nozzle. This piece of metal is retained within the nozzle, and the supply of inert gas is commenced to the nozzle. A light source (e.g., a laser) irradiates the retained piece of metal while causing the supplied inert gas to flow from apertures formed in the nozzle. The metal melted by the light source is ejected from the nozzle with the supplied inert gas, causing it to adhere to both parts. The two parts are then connected together through the hardening of the molten metal. Accordingly, blockage of the ejection port of the nozzle is prevented and there is a suitable connection between the parts using the metal. Moreover, the inert gas flows from the apertures in the direction of the two parts which improves wettability.
In various embodiments, the inert gas flows from apertures which are formed, at least in part, on the inflow side of the position in which the piece of metal and the inner surface of the nozzle are in contact. Also, the inert gas is flows from apertures which extend to the ejection outlet for the molten metal. As such, the inert gas is enabled to effectively flow downward. Additionally, oxidation of the metal is prevented and wettability improved.
The retained piece of metal is irradiated with a laser beam while inert gas is made to flow from a plurality of apertures formed in the nozzle.
In one embodiment, the piece of metal is retained in the nozzle by being retained on surfaces which slope inward in the direction in which the piece of metal flows outward. Accordingly, it is easier for the molten metal to flow and to reliably prevent blockage of the ejection outlet for the nozzle.
In another embodiment, the solder ball is retained by a plurality of claws separated around the periphery by a plurality of apertures extending to the ejection outlet for the molten metal.
In a further embodiment, a device causes molten metal to adhere between two connecting parts in a head gimbal assembly. The two parts are connected together by hardening of the metal.
The device includes a transportation unit which transports the piece of metal and a nozzle. The nozzle includes a retaining section which retains the piece of metal transported from the transportation unit, an ejection outlet which ejects the piece of metal towards the two connecting parts, and apertures from which an inert gas flows. The device also includes an inert gas supply device which supplies an inert gas into the nozzle, and a laser device which melts the piece of metal by irradiating the metal with a laser beam as inert gas flows from the apertures after the inert gas supply device has commenced supplying inert gas into the nozzle.
An embodiment of the invention will now be described. To make the description more clear, descriptions and drawings may be abbreviated or simplified as appropriate. Moreover, identical elements within the drawings are keyed identically, and repeated descriptions will be omitted as necessary for the sake of clarity. The description of the embodiment uses a hard disk drive (HDD) as an example of a disk drive. The embodiment is characterized in a technology for connecting parts together which employs a piece of metal for the connecting parts in the head gimbal assembly (HGA). In one embodiment, the piece of metal is spherical. Gold or solder can be considered as examples of material for the piece of metal. The following description refers to the connection of parts using a solder ball.
In various embodiments, a solder ball is used for connecting together the connecting parts for the gimbal and the connecting parts for the head slider. In addition, a solder ball is applied in an HGA with a micro-actuator to connect together connecting parts of the head slider and the connecting parts for the micro-actuator. In one such embodiment, a solder ball is used for connecting together the connecting parts of the micro-actuator and the connecting parts for the gimbal.
Suspension 14 is constructed with gimbal 142 fixed to the side of load beam 141 which retains head slider 12, and mounting plate 143 fixed to the rear of the side of load beam 141 which retains head slider 12. Load beam 141 has the function of a spring which generates a fixed load to balance out the flotation force on head slider 12. Gimbal 142 supports head slider 12 where changes in the position of head slider 12 cannot be prevented. Furthermore, a gimbal tank is formed in gimbal 142. Head slider 12 is then fixed to the gimbal tank.
Trace 13 makes an electrical connection between head slider 12 and the preamp IC (not shown). Trace 13 is formed with insulating sheets provided to prevent contact between the plurality of lead wires. End 131 is one end of wiring 13 that is connected to the substrate on which preamp IC is located. Suspension connecting part 144 is formed at the other end of trace 13 on the side of head slider 12, as shown in
As shown in
In contrast, in conventional technology, a solder ball is positioned between a suspension connecting part and a slider connecting part with the solder being melted to connect the two parts together.
The manufacture of an HDD begins with the manufacture of head slider 12. Suspension 14 is then manufactured separately to head slider 12. The manufacture of suspension 14 is done by manufacturing gimbal 142, load beam 141, and mounting plate 143. In various embodiments, gimbal 142, load beam 141, and mounting plate 143 are fixed together by laser spot welding or the like. Gimbal 142 may be formed using a photolithographic process or an etching process, and wiring 13 may also be formed together with the stainless steel gimbal body.
HGA 1 is manufactured by mounting head slider 12 on suspension 14. Thereafter, an arm and a VCM coil are fixed on HGA 1, and a head stack assembly (HSA), an assembly of the actuator and head slider 12, is manufactured. In addition to the manufacture of the HSA, a top cover is fixed to the base after fitting a spindle motor, a magnetic disk and the like on the base. The HDD is then completed by writing servo data into the magnetic disk and fitting the control circuit.
The process of connecting together suspension connecting parts 144 and slider connecting parts 121 in the process of manufacturing HGA 1 of the embodiment will now be described in more detail.
The flow of the process for connecting together head slider 12 and suspension 14 will now be described with reference to the schematic diagrams in
Soldering device 2 is provided with a control device (not shown in the diagram). This control device controls the constituent elements of soldering device 2 and carries out the process of soldering. Soldering device 2 moves nozzle 21, retained by nozzle holder 22, toward HGA 1 (before completion), and positions it relative to connecting parts 121, 144 together. The tip of nozzle 21 is moved close to the two parts 121, 144 in a position facing them. In one embodiment, nozzle 21 is moved relative to HGA 1. In another embodiment, HGA 1 is moved relative to nozzle 21 (nozzle holder 22).
Solder ball 32 is removed by suction part 28 from solder ball supply device 29 in which solder balls 32 are stored (S 12). Solder ball supply device 29 blows solder balls 32 up from the bottom by blowing out gas (e.g., inert gas, typically nitrogen). An opening is provided on the top of solder ball supply device 29. A solder ball 32 which has been blown up is ejected from this opening. The ejected solder ball 32 is then sucked along suction part 28 positioned at this opening.
When solder ball 32 is in position, suction part 28 moves it upwards away from the opening. By this means, solder ball 32 is transferred to solder ball transportation pipe 26. As shown in
Transportation tube 26 and nozzle holder 22 comprise solder ball 32 transportation unit. The transportation unit which transports solder ball 32 to nozzle 21 is not limited to the structure in this embodiment, and may have any structure. For example, solder ball 32 may be dropped into nozzle holder 22 through the rotation of suction part 28 after being picked up from solder ball supply device 29. In this way, the need for solder ball transportation tube 26 in
Solder ball 32 drops into nozzle 21 through the flow of inert gas and gravity. In one embodiment, the direction of motion (downward) of solder ball 32 (the direction of the path) is vertical, but need not always be arranged this way. As shown in
Soldering device 2 is provided with camera 23 which photographs solder ball 32 retained in nozzle 21. Soldering device 2 uses this image to confirm the number of solder balls retained. Moreover, in response to the first solder ball retained, the image is used to start the supply inert gas (typically nitrogen gas) to nozzle 21. Where two or more solder balls are retained, soldering device 2 withdraws the retained solder ball to the inlet side, and transfers a new solder ball 32 from solder ball supply device 29.
As shown in
As shown in
Laser device 27 ceases to irradiate a laser beam when the solder has been ejected (S 18). It should be appreciated that laser device 27 can be any light source generating a light that is able to melt solder ball 32. The laser beam irradiation ceases before the molten solder adheres to suspension connecting parts 144 and slider connecting parts 121, or alternatively continues slightly after it has become adhered. The solder which has dropped down onto connecting parts 121, 144 in a molten state and adhered to them then hardens, connecting together connecting parts 121, 144 (S 19).
As described above, soldering device 2 causes inert gas to flow within nozzle 21 before irradiation with the laser beam. This nozzle 21 has apertures through which the inert gas flows out, and there is no excessive buildup of pressure within nozzle 21 even where solder ball 32 is retained near the ejection outlet. When solder ball 32 is melted by the laser beam, the molten solder is simultaneously ejected towards connecting parts 121, 144 from nozzle 21 due to the compressed inert gas (flow of inert gas). In this way, there is no time difference present between the melting of the solder and its ejection, the molten solder is unlikely to remain within nozzle 21, and does not tend to block the solder retention unit.
As there is an inert gas atmosphere at least present on the inlet side of solder ball 32, it is possible to prevent oxidation of the melting solder ball 32 with a laser beam. In one embodiment, solder ball 32 is kept in an inert gas atmosphere both on the inflow and outflow sides. In another embodiment, the inert gas which flows from the inert gas outflow apertures in nozzle 21 flows to the outflow at side of solder ball 32. In a further embodiment, the shape and position of the inert gas outlet apertures allow the inert gas flowing outward so that solder ball 32 is kept within an atmosphere of inert gas on both the inlet side and the outlet side.
The molten solder adheres to connecting parts 121, 144. The molten solder then hardens on connecting parts 121, 144 to connect them together. To ensure a suitable wettability for the solder on connecting parts 121, 144, connecting parts 121, 144 are held within an inert gas atmosphere at the time that the solder adheres. In one embodiment, the inert gas flowing from the outflow apertures in inert gas of nozzle 21 flows onto connecting parts 121,144, and connecting parts 121, 144 are kept in an atmosphere of inert gas during the time that the molten solder adheres and hardens. By designing the position and shape of the apertures for the outflow of inert gas appropriately, it is possible to have the inert gas flowing out so that connecting parts 121, 144 are kept in an atmosphere of inert gas.
The solder ball retention unit in nozzle 21 will now be described with reference to
The four claws 71a-71d are separated by four slits (apertures) 72a-72d. The four slits 72a-72d penetrate to the outside from the inside of solder ball retention unit 7. The four slits 72a-72d are respectively positioned between adjacent claws in the peripheral direction. In one embodiment, claws 71a-71d join together in an upper area not shown in the diagram, with nozzle 21 formed of one continuous part.
The region surrounded by claws 71a-71d (excluding slits 72a-72d) is the pathway for solder ball 32, this pathway being connected with the outside of nozzle 21 via slits 72a-72d. With this structure, the cross-section of the pathway which extends in the direction through which the solder drops (the vertical direction, the direction along which the laser beam is irradiated) is rectangular. In other words, the respective inner surfaces of claws 71a-71d which comprise the inner wall of the pathway comprise two surfaces at right angles to one another. The inner surfaces of claws 71a-71d may also be curved. In this example, the outer surfaces of claws 71a-71d are respectively formed from two surfaces at right angles to one another.
As shown in the oblique view of claw 71a in
Sloping surface 711a slopes in the direction in which solder ball 32 (molten solder) drops, and approaches the center of the pathway as it progresses towards the outflow side. The other three sloping surfaces 711b-711d have identical slopes. These sloping surfaces cause the inner diameter of the pathway to narrow as it approaches solder ejection outlet 74, with part of the downflow side (lower side) of solder ball 32 being retained by the four sloping surfaces. Thus, as solder ball 32 is retained on sloping surfaces, the molten solder can easily flow to the outside with the flow of inert gas, further reducing the possibility of solder remaining within solder ball retention unit 7 as the molten solder is expelled by the flow of inert gas.
Solder ball retention unit 7 is provided with solder ejection outlet 74 at its tip (not including slits 72a-72d). The minimum diameter of this solder ejection outlet 74 is less than the diameter of solder ball 32. In the structure of this example, the maximum diameter is also smaller than the diameter of solder ball 32. Solder ball 32 retained by claws 71a-71d melts in the laser beam, and is blown out from solder ejection outlet 74. In
As described with reference to the flowchart in
With this structure, slits 72a-72d go beyond the upper end (inflow end) of solder ball 32 retained from solder ejection outlet 74 (the tip of the nozzle), and extend to the upper side (inflow side). Solder ball 32 is exposed from top to bottom through slits 72a-72d. In this way with slits 72a-72d that extend from the inflow end of solder ball 32 to solder ejection outlet 74, contact between surface of the molten solder. Accordingly, solder ball retention unit 7 (nozzle 21) is reduced, making it less likely that there will be blockage in solder ball retention unit 7 (nozzle 21).
With these slit shapes, inert gas flowing out from slits 72a-72d is able to effectively flow over solder ball 32 and connecting parts 121, 144. In this way it is possible to surround solder ball 32 and connecting parts 121, 144 with inert gas. Thus, a proper connection is formed between connecting parts 121, 144 in an atmosphere of inert gas as the melting of the solder and the bonding occur with solder ball 32.
Slits 72a-72d thus act as the outflow aperture for the inert gas, enabling inert gas to be supplied to nozzle 21 prior to irradiation with a laser beam (before the solder melts) and enabling the solder to be ejected simultaneously with the melting of the solder. Moreover, as the inert gas within nozzle 21 flows around the solder ball, it is possible to suppress oxidization of the solder. Furthermore, the inert gas flowing out from slits 72a-72d flows over solder ball 32 and connecting parts 121, 144, enabling connecting parts 121, 144 to be connected together by molten solder in an atmosphere of inert gas.
In addition to reducing contact surfaces for the molten solder, slits are formed over a wide area from the solder ejection outlet 74 to the inlet position for solder ball 32 as shown in the slit shapes shown in
To allow inert gas to flow out effectively from the apertures (slits), the apertures (at least part of them) are be formed at support position X of solder ball 32 or in a region above this. The examples of the structure shown in
To reduce the contact area for the molten solder and prevent the nozzle from blocking, the slits include a region from solder ball support position X to solder ejection outlet 74, as shown in this structure (and the structures in
The slits of the solder ball retention unit are typically the same shape. However, slits of differing shapes may be formed. In one embodiment, at least two of the plurality of slits are formed so as to face each other across the pathway. In other words, at least two of the plurality of slits are aligned in the perpendicular direction with direction of drop at the center of the pathway.
As described with reference to
The content described in
Solder ball retention unit 9 is provided with four claws 91a-91d. These four claws 91a-91d are separated by slits (apertures) 92a-92d formed between these. As the structure of solder ball retention unit 9 is similar to the structure of solder ball retention unit 7, a description will be given of the differences. The inner surfaces of claws 91a-91d are curved surfaces, with the cross-section of the pathway these form being a circle (excluding slits 92a-92d). Moreover, the outer surfaces of claws 91a-91d are also curved, so that solder ball retention unit 9 is approximately cylindrical.
The solder ball support surfaces 911a-911b for claws 91a-91d are not sloping surfaces but horizontal surfaces which project to the inside. The retaining surface for solder ball 32 is the bottom of the pathway. The retained solder ball 32 is in contact with the angles of the horizontal surfaces of claws 91a-91d, and is retained there. As described above, retaining surfaces are sloping surfaces to allow the molten solder to flow effectively. However, from the point of view of ease of manufacture for the solder ball retaining unit, a horizontal retaining surface is effective.
Solder ball retention unit 10 is provided with four claws 101a-101d. The four claws 101a-101d are separated by slits (apertures) 102a-102d formed between these in the peripheral direction. The four claws 101a-101d have their side parts 103a-103d bent inward. This claw shape allows the pathway to gradually reduce towards solder ejection outlet 104, and solder ball 32 stops and is retained in the position where its minimum diameter is smaller than the diameter of the solder ball. The inner surfaces of parts 103a-103d on the outflow side are bent in the horizontal direction, and the contact with solder ball 32 is linear.
Slits 102a-102d extend to solder ejection outlet 104 (the tip) from a position above the top of the retained solder ball 32. With this slit shape it is possible to have an identical effect to that of the structure described with reference to
This solder ball retention unit 11 has a structure similar to that of solder retention unit 10. The outer surfaces and inner surfaces of claws 111a-111d are plane surfaces, the difference being that with solder ball retention unit 10 the outer surfaces and inner surfaces of parts 103a-103d on the outflow side are curved surfaces. As the inside surfaces to which solder ball 32 is in contact are plane surfaces, the contact between solder ball 32 and the inner surfaces of the claws is a point contact.
Slits 112a-112d of solder ball retention unit 11 are formed in the range from solder ejection outlet 114 (tip) to the upper end of claws 111a-111d. With this slit shape, slits are formed from above the top of the retained solder ball 32, and in terms of the effect of the inert gas flow a similar effect is obtained to solder ball retention unit 7 described with reference to
It should be appreciated that descriptions of nozzles with different structures have been given with reference to different drawings, but these elements may be applied separately or used in combination.
Embodiments of the present invention are particularly useful in the manufacture of an HGA than HDD, but may also be applied to an HGA used in other disk drives. Embodiments of the present invention can also be used to make connections within the HGA in addition to making connections between the head slider, micro-actuator and suspension. Moreover, the number of contact points between the connections may vary with the design of the HGA. Furthermore, connections between the connecting parts may be made by melting a piece of metal with a shape other than a sphere where this does not present problems with transportation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-278859 | Dec 2009 | JP | national |
