KR100762216B1 - Method for manufacturing a head stack assembly - Google Patents

Abstract

A method for manufacturing a head stack assembly is provided to minimize defect generated in a slider, and to improve yield by applying a bonding epoxy to the suspension before the suspension is coupled with one end of the actuator. A flexible printed circuit is combined with an actuator(S110). A bonding epoxy is applied to a suspension(S125). The suspension is coupled with one end of the actuator(S120). A slider is tested and selected(S135). The slider is coupled with one end of the suspension(S130).

Description

Method for manufacturing a head stack assembly

1 is a plan view schematically showing a hard disk drive.

2 is a flow chart showing a method of manufacturing a conventional head stack assembly.

Figure 3 is a flow chart showing a method of manufacturing a head stack assembly according to an embodiment of the present invention.

4 is a schematic cross-sectional view showing the epoxy applied to the suspension.

* Description of the symbols for the main parts of the drawings *

10: hard disk drive

20: magnetic disk

40: head stack assembly

41: slider

43: Suspension

45: actuator

The present invention relates to a manufacturing method of a head stack assembly, and more particularly, to a manufacturing method of a head stack assembly capable of preventing the yield from being lowered due to a defect generated in a static sensitive slider. .

In general, a computer includes an auxiliary memory device as an auxiliary means of a main memory device, and records a large amount of data in the auxiliary memory device. In the case of a personal computer, a hard disk drive having at least one magnetic disk installed therein is widely used as a secondary memory device.

1 is a plan view schematically showing a hard disk drive.

Referring to FIG. 1, the hard disk drive 10 records data on a base 11, a magnetic disk (hereinafter referred to as a disk 20), which is a recording medium for storing data, and a disk 20. A head stack assembly 40 for regeneration and a voice coil motor 50 which provides a driving force for moving the head stack assembly in the radial direction of the disc.

The head stack assembly is pivotally rotatable about a pivot shaft 35 fixed on a base, an actuator 45 forming a main body portion thereof, and a plate-type coupled to one end of the actuator. A suspension (43) and a slider (41) fixed at the end of the suspension and serving as a magnetic head for recording / reproducing data on the disc, and at the other end of the actuator (45) a voice for rotating the head stack assembly. The coil 47 is formed.

A manufacturing method of a conventional head stack assembly for assembling the head stack assembly will be described.

2 is a flow chart showing a conventional method for manufacturing a head stack assembly.

As shown in Figure 2, according to the conventional manufacturing method of the head stack assembly, a slider acting as a magnetic head is fixed to one end of the suspension (S10).

The slider acts as a magnetic head adjacent to the disc, which is directly responsible for the function of recording / reproducing information on the disc, and is attached in position as a flexure on the suspension. The slider seated on the flexure is fixed to the suspension by applying ultraviolet light and heat, and an electrical connection is made through wire bonding between the slider and the suspension.

The slider is thus assembled to the suspension to form a head gimbal assembly (hereinafter referred to as HGA). Visual inspection and mechanical inspection are performed on a sample basis for the assembled HGA, which includes a gram load test, a bonding strength test, and an x-y alignment test.

A dynamic electrical test (DET) is performed on the HGA that passes the mechanical inspection. The DET is a test that loads an HGA onto a rotating disk and records / reproduces information on the disk. Measure up to ability.

Next, the flexible circuit board is coupled to the actuator (S20). The actuator is a body that serves as a support for the head stack assembly and attaches a thin, flexible flexible printed circuit to it. Flexible printed circuits include circuits such as preamps that control the electrical connections and electrical operation of the head stack assembly. The other end of the actuator is coupled to the voice coil, the voice coil and the flexible printed circuit is connected.

Then, the suspension is coupled to one end of the actuator (S30) to complete the head stack assembly, and when the head stack assembly is assembled with the disk, a hard disk drive is formed.

The slider, which acts as a magnetic head in the head stack assembly, is a key component for recording / reproducing information on a disc, and is very sensitive to static electricity or shock generated during manufacturing of the head stack assembly. However, in the conventional manufacturing method of the head stack assembly, the slider is assembled to the suspension first, followed by subsequent processes, which increases the possibility of the slider being exposed to external shocks due to static electricity and handling. there is a problem.

This causes a lot of defects in the slider in the conventional manufacturing method of the head stack assembly, and if such a defect occurs, not only the slider but also the remaining parts of the slider, for example, the HGA or the head stack assembly are defective at once. There is a drawback to higher costs due to bigger losses.

In addition, in order to reduce the defects generated in the slider in the conventional manufacturing method of the head stack assembly, there is a problem that the cost of the head stack assembly increases as the facility investment is increased so that static electricity or contamination does not flow in the manufacturing environment.

Therefore, the present invention has been made to solve the problems of the prior art as described above, the object of the present invention is to reduce the defects generated in the slider by the handling of static electricity or components generated during the manufacturing process, assembly by the slider failure It is another object of the present invention to provide a method for manufacturing a head stack assembly that can be prevented from being discarded by increasing other components.

It is also an object of the present invention to provide a manufacturing method of a head stack assembly in which the yield is increased by simplifying the manufacturing process, reducing the cost required for improving the manufacturing environment, and preventing the inflow of defective parts into the manufacturing process.

A method of manufacturing a head stack assembly according to an embodiment of the present invention for achieving the above object is used to store information on one or more disks, comprising: coupling a flexible printed circuit to an actuator; A suspension coupled to one end of the actuator; And engaging a slider at one end of the suspension.

In a preferred embodiment, the method further comprises the step of testing and selecting the slider before the step of coupling the slider to one end of the suspension, wherein the slider is tested for the characteristics of recording / playback on a rotating disc using a jig. It is characterized by.

In a preferred embodiment, before the suspension is coupled to one end of the actuator, it is characterized in that the adhesive epoxy for coupling the slider on the suspension is applied.

In a preferred embodiment, the epoxy is applied using a mask pattern in close contact with the suspension for adjusting the size and height of the epoxy applied on the suspension.

In a preferred embodiment, the epoxy applied on the suspension is partially cured, and a safety liner in the form of a film is attached to the epoxy applied on the suspension.

In a preferred embodiment, the epoxy is characterized in that it comprises a thermoplastic.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a flow chart showing a method of manufacturing a head stack assembly according to an embodiment of the present invention.

As shown in Figure 3, according to the manufacturing method of the head stack assembly of the present invention, a flexible printed circuit board (Flexible Circuit Board) is coupled to an actuator (actuator) (S110). The actuator is the body that serves as the support for the head stack assembly and attaches a thin, flexible, flexible printed circuit to it. Flexible printed circuits include circuits such as preamps that control the electrical connections and electrical operation of the head stack assembly.

A voice coil is then coupled to the other end of the actuator, connecting the voice coil and the flexible printed circuit.

A suspension is coupled to one end of the actuator (S120) to assemble a suspension stack assembly (hereinafter referred to as SSA). In this case, since there is no slider in the suspension, there is no need for a test unlike in the prior art, and there is an advantage in that the process adjustment is easy. In this case, the operation of coupling the suspension to one end of the actuator may be performed automatically in a separate device, and thus the operation may be simplified.

It is preferable that visual inspection and mechanical inspection are performed on a sample basis for the SSA thus assembled. Mechanical inspections include gram load tests, torque tests, and x-y alignment tests.

After the SSA is assembled, the slider is assembled to one end of the suspension coupled to the SSA to complete the head stack assembly (S130). The process of coupling and securing the slider to the suspension proceeds as follows.

The suspension-coupled SSA is fixed at the assembly position, and an adhesive epoxy is applied at the bonding position to which the slider is to be bonded. At this time, the position where the SSA is fixed is to determine a reference point in the equipment in which the SSA is fixed, and the position of the suspension using the reference point is confirmed using, for example, a vision system. Repeating adjustment and confirmation so that the position of the suspension is fixed at a fixed position in a certain error range is the same as that performed in automated bonding equipment or the like in the same manner as in the related art.

Epoxy is applied to the flexure position at which the slider is assembled to the suspension of the fixed SSA, and the slider is seated on the flexure by the robot. The slider seated on the flexure is preferably fixed to the suspension at ultraviolet or room temperature.

However, in the process of assembling the slider to the suspension by the manufacturing method of the head stack assembly of the present invention, unlike the conventional case in which the slider is coupled to each independent suspension, the suspension coupled to the SSA is dense together in a limited space. Become a process to be combined.

Therefore, it is difficult to apply epoxy precisely in a narrow space in order to couple the slider to the suspension of the SSA in such an environment. In the manufacturing method of the head stack assembly of the present invention, in order to solve this difficulty and to facilitate the coupling of the suspension and the slider, it is more preferable to apply an epoxy to the suspension before the suspension is coupled to the actuator (S125).

Epoxy applied to the suspension may include, for example, 10% to 30% by weight of silver particles used as a conductor in a solvent such as pressure sensitive adhesive (PSA) or ultra violet-PSA (UV-PSA). Thermoplastics, 30% to 60% by weight.

In this case, the solvent used may be one selected from the group consisting of synthetic rubber PSA, natural rubber PSA, acrylic PSA, and the like, and thermoplastic polyurethane may be used as the thermoplastic. In particular, the acrylic PSA has the advantage of reducing the impact or vibration caused by the surrounding environment while the slider of the hard disk is flying (flying) on the disk, it has a desirable feature as an adhesive epoxy material of the slider. Silver particles can be used in pure silver or alloy form.

Referring to the process of applying the adhesive epoxy on the suspension in detail as follows.

The mask pattern is brought into close contact with the flexure position of the suspension to which the epoxy mixed with the above-described solvent, silver particles and thermoplastic plastic is to be applied. The mask pattern is formed with an opening limiting the size and thickness of the epoxy applied to the flexure, the size and thickness of the epoxy applied to the suspension can be easily adjusted by adjusting the size and thickness of the opening, using a mask pattern This has the advantage that the productivity of the process of applying the epoxy is improved.

4 is a schematic cross-sectional view showing an epoxy applied to the suspension.

As shown in FIG. 4, the epoxy 120 is applied to the flexure 110 of the suspension 100 to which the mask pattern is closely adhered, and the epoxy 120 is partially cured by using ultraviolet rays. The degree of curing is preferably, for example, about 35% to 50%. This serves to maintain the shape of the epoxy 120 applied to the flexure 110, and removes the mask pattern after the epoxy is partially cured.

In order to protect the epoxy 120 having a predetermined shape, the release liner 130 in the form of a film made of paper or polyethylene is attached on the epoxy 120 applied to the suspension 100. It is preferable. The safety liner 130 preferably uses polyethylene, which prevents the epoxy from curing and can be easily removed without damaging the epoxy prior to attaching the slider.

When the adhesive epoxy is previously applied to the suspension in the same manner as described above, it is easy to couple the slider to the suspension of the SSA, which has the advantage of improving productivity.

If a certain type of epoxy is formed in the suspension, the SSA from which the safety liner has been removed is fixed in the assembly position and the slider is seated on the epoxy in the manner described above. The seated slider is preferably fixed by applying ultraviolet rays and heat.

Subsequently, wire bonding is performed between the slider and the suspension to complete the head stack assembly in which the slider and the SSA are completed.

In the manufacturing method of the head stack assembly of the present invention described above, since the slider is assembled to the SSA without being assembled, the slider is continuously attached to the suspension until the head stack assembly is completed. Unlike the conventional method in which the assembling process proceeds, there is an advantage of minimizing the occurrence of a defect in the slider by the electrostatic or impact while the assembling process is in progress.

In addition, since the slider is coupled to the head stack assembly at the last stage just before the head stack assembly is completed, the environment in which the slider to be assembled is exposed in the process is minimized, so that the manufacturing method of the head stack assembly of the present invention can be treated with static electricity during handling. Since the defect generated in the slider is reduced, the loss in which the head stack assembly to which the slider is assembled is discarded together with the rest due to the defect of the slider is reduced.

In addition, as in the conventional method of manufacturing the head stack assembly, since the slider is first assembled and the requirements of the facility for minimizing the impact of the slider from the surrounding environment are alleviated, the investment cost required for this is also reduced.

And the slider is coupled to the suspension of the SSA assembled in the manufacturing method of the head stack assembly according to the present invention to complete the head stack assembly, if the defective product flows into the slider used at this time, because this causes the head stack assembly of the defective product Coupling the slider to the SSA does not maximize the effect of the present invention to minimize the defects occurring in the slider during the assembly process.

Therefore, in order to prevent such a loss, it is preferable to perform a thorough test before the slider coupled to the SSA is coupled to the SSA, thereby combining the slider from which the defect is removed with the SSA (S135). In order to prevent defects from entering the SSA at the slider level, it is preferable to perform a dynamic electrical test (hereinafter referred to as DET) on the slider before combining with the SSA.

DET is a test performed by loading an HGA onto a rotating disk in a state where a head gimbal assembly (HGA) is assembled in the conventional case, and measuring the ability to record / reproduce information on the disk. It is desirable to be applied in the most strict way to check the performance of the slider.

In order to perform DET rather than simple electrical characteristics test at the slider level, a mechanism is required to fix the slider and load it on a rotating disk. As described in US Pat. No. 6,459,260 or US Pat. It is preferable to produce and implement a jig which can be made.

The jig makes stable electrical connection with the slider while performing a DET on the slider.

As described above, if sufficient testing is carried out, for example via DET, before the slider is coupled to the suspension, a slider with poor or poor characteristics is introduced to prevent the failure of the head stack assembly. As a result, the yield of the produced head stack assembly is increased.

In the above, the configuration and operation of the present invention have been shown in accordance with the above description and drawings, but this is merely described, for example, and various changes and modifications are possible without departing from the spirit and scope of the present invention. Of course.

As described above, according to the present invention, the following effects are achieved.

The method of manufacturing the head stack assembly of the present invention reduces the process of handling sliders sensitive to static electricity and external shocks, and reverses the order of the steps in which the slider is assembled to the suspension, thereby eliminating static or component generated during the manufacturing process. There is an effect of improving the yield by minimizing the defect generated in the slider by the handling.

In addition, the manufacturing method of the head stack assembly of the present invention simplifies the manufacturing process to reduce the cost required to improve the manufacturing environment, and prevents the failure of the slider to be introduced into the manufacturing process to prevent disposal of other parts assembled to reduce the cost It has the advantage of saving.

Claims (8)

In a method of manufacturing a head stack assembly used for storing information on one or more disks, Coupling a flexible printed circuit to the actuator; A suspension coupled to one end of the actuator; And And coupling a slider to one end of the suspension. The method of claim 1, And before the slider is coupled to one end of the suspension, the slider being tested and selected. The method of claim 2, And the slider is tested for the characteristics of recording / playback on a rotating disc using a jig. The method of claim 1, Before the suspension is coupled to one end of the actuator, a bonding epoxy for coupling the slider on the suspension is applied, characterized in that the manufacturing method of the head stack assembly. The method of claim 4, wherein And the epoxy is applied using a mask pattern in close contact with the suspension for adjusting the size and height of the epoxy applied on the suspension. The method of claim 4, wherein And wherein said epoxy applied on said suspension is partially cured. The method of claim 4, wherein And a film-type safety liner is attached to the epoxy applied on the suspension. The method of claim 4, wherein And the epoxy comprises a thermoplastic.

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