JP3990638B2 - Slider peeling method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a slider peeling method executed for reusing a member in a magnetic head assembly when the slider has poor characteristics.
[0002]
[Prior art and its problems]
A so-called magnetic head assembly used in a hard disk drive (HDD) includes, for example, a flexure 202 made of a flexible thin metal plate fixed to a load beam 203 by spot welding, for example, as shown in FIG. A slider 201 integrally formed with an electromagnetism conversion element is bonded to the tip of the flexure 202 to balance the elastic force of the load beam 203 and the fluid force generated between the slider 201 and the rotating hard magnetic disk. Thus, the distance between the ABS (Air Bearing Surface) surface of the slider 201 and the hard magnetic disk is maintained. Such conventional magnetic head assemblies are disclosed in, for example, JP-A-7-73625, JP-A-10-269538, JP-A-2000-21709, JP-A-2000-105913, and the like.
[0003]
This type of magnetic head assembly is subjected to dynamic characteristic inspection before shipment. The dynamic characteristic inspection is performed in a state in which the slider 201 is attached to the flexure 202 fixed to the load beam 203 and attached to a spin stand or the like and the hard magnetic disk is rotated. Since this dynamic characteristic inspection is a final inspection, if the characteristic does not satisfy the standard, it is determined as defective. Conventionally, when it is determined that the dynamic characteristic is defective, even if the cause of the defect exists in the slider 201, all the magnetic head assemblies are discarded, and the yield is lowered.
[0004]
Therefore, recently, when the cause of the failure exists in the slider 201, it is desired to remove the slider 201 from the flexure 202 and reuse the flexure 202 and the load beam 203.
[0005]
However, since the flexure 202 is very thin and fragile as compared with the load beam 203, the flexure 202 is easily deformed when the slider 201 is peeled from the flexure 202 fixed to the load beam 203. And it was difficult to reuse the load beam 203. Conventionally, a flexible wiring board that connects the slider 201 (electromagnetic transducer) and a circuit system of a device to which the magnetic head assembly is mounted is mounted on the surface of the flexure 202, and the slider 201 is moved from the flexure 202. When it is attempted to peel off, the wiring pattern of the flexible wiring board is peeled off together with the slider 201, making reuse more difficult.
[0006]
OBJECT OF THE INVENTION
The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a slider peeling method capable of peeling a slider from a flexure without deforming the flexure and a wiring pattern.
[0007]
SUMMARY OF THE INVENTION
The present invention focuses on the fact that if a slit is previously cut into the bonding bonding portion of the slider, the stress applied to the flexure and the wiring pattern is reduced when the slider is peeled off, and deformation of the flexure and the wiring pattern can be prevented. However, Au is frequently used as a material for forming the bonding adhesion portion, and when the cut is made in the Au bonding adhesion portion, the cut or no cut portion is caused by the malleability and ductility of Au itself. It spreads out and sticks to the adjacent Au bonding adhesion part. If the present inventor uses not an ordinary cutter but an ultrasonic cutter that cuts a member while applying ultrasonic vibration, even if it is a metal material having malleability and ductility such as Au, Ag, Cu, and solder. And found that a cut can be formed.
[0008]
That is, the present invention includes a slider integrally provided with an electro-magnetic transducer, a flexible flexure in which the slider is bonded by a bonding adhesive portion made of Au, Ag, or Cu, and the surface of the flexure. In a magnetic head assembly including a flexible wiring board electrically connected to the electro-magnetic transducer through the bonding adhesion portion, a method of peeling the slider from the flexure when the slider has poor characteristics Then, the step of fixing the flexure on the surface opposite to the surface on which the bonding bonding portion of the slider is provided, and the flexure is fixed, and an incision is formed in the bonding bonding portion with an ultrasonic cutter , a step of leaving a joint portion of a bonding adhesive portion and the flexure at the distal end of該切write unit, flexible In a state of fixing the turbocharger, and the tip of the cutting portion formed in the bonding adhesive portion as a fulcrum is raised the slider, by pulling away the slider from the bonding adhesive portion, the step of peeling the flexure with bonding adhesive portion It is characterized by including.
[0009]
In the step of peeling off the slider, it is preferable that a part of the bonding adhesion portion is left on the flexible wiring board, and the slider and the bonding adhesion portion are peeled off from the flexure. The ultrasonic cutter is preferably moved, for example, substantially parallel to the surface of the flexure, thereby forming a cut in the bonding portion.
[0010]
In many cases, the slider is bonded by a resin adhesive separately from the bonding bonding portion. Thus, when the resin adhesive is used, it is preferable to perform the heating process which reduces the adhesive strength of a resin adhesive at least after the notch formation process by an ultrasonic cutter.
[0011]
According to the above steps, the slider and the bonding adhesive portion can be easily peeled off from the flexure without deforming the flexure and without peeling off the wiring pattern of the flexible wiring board mounted on the surface of the flexure. . Then, the flexure after the slider and the bonding bonded portion are peeled can be reused, leading to an improvement in yield.
[0012]
As the ultrasonic cutter, it is preferable to use an ultrasonic cutter having a blade formed of a hard material such as cemented carbide, ruby, zirconia, or diamond so that a cut can be easily formed in the bonding bonded portion.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of a magnetic head assembly (completed state) for a hard disk drive to which the present invention is applied. The magnetic head assembly 1 includes a slider 11 in which an electro-magnetic transducer (magnetic head) 13 is incorporated, and a flexure 21 to which the slider 11 is fixed. The flexure 21 is a thin metal plate having a flexible shape like a leaf spring, and is attached to the tip end portion of the load beam 31 in a state where the slider 11 is elastically supported in a floating manner with respect to the load beam 31. Flexible wiring boards (FPC) 22 and 23 are fixed to the surface of the flexure 21 by bonding with an adhesive or the like.
[0015]
As shown in an enlarged view in FIG. 2, the flexible wiring boards 22 and 23 have terminal portions 22a, 22b, 23a, and 23b disposed at the distal end portion of the flexure 21, and these terminal portions 22a, 22b, 23a, and 23b. After being separated into both side edges, it extends along both side edges, is further pulled out from the rear end edge of the flexure 21, and is integrated together via the relay flexible wiring board 24. Each terminal at the end of the flexible wiring board for relay 24 is connected to a control circuit (electronic component) of the hard magnetic disk drive on which the magnetic head assembly 1 is mounted. The slider 11 is bonded to the terminal portions 22a, 22b, 23a, and 23b by a bonding adhesive portion 25, and the terminals (not shown) of the electro-magnetic transducer 13 are conducted. The bonding adhesion part 25 of this embodiment is formed of Au.
[0016]
Next, the dynamic characteristic inspection process of the magnetic head assembly 1 will be described.
The dynamic characteristic inspection of the magnetic head assembly 1 is performed by mounting the completed magnetic head assembly 1 with the flexure 21 mounted on the load beam 31 on an inspection machine such as a spin stand. As a result of the dynamic characteristic inspection, the magnetic head assembly 1 determined to be non-defective is a product.
[0017]
FIG. 3 shows an embodiment of an inspection apparatus for inspecting dynamic characteristics. The inspection apparatus 100 rotates a magnetic disk 103 with a magnetic head for recording information on a disk-shaped magnetic recording medium (hereinafter referred to as a magnetic disk) 103 and reproducing information on the magnetic disk 103. It is a device that inspects the characteristics in the state of floating. As shown in FIG. 3, the inspection apparatus 100 includes a magnetic disk 103 that is rotated by a spindle motor 101, an arm 105 that fixes a magnetic head assembly, and an actuator that moves the arm 105 precisely. 107, a motion conversion mechanism 109 and a cross roller table 111 are provided. These members are mounted on a base frame (not shown).
[0018]
The motor 107 is fixed to the base 115 via a bracket 113. A space is formed between the base 115 and the bracket 113, and the motion conversion mechanism 109 is disposed in this space. The base 115 is attached to the base frame so that the position can be adjusted as necessary. For example, a direct current motor (DC motor) or a stepping motor can be used as the motor 107. The magnetic head (slider) mounted on the arm 105 is finely moved in the diameter direction (X direction) of the magnetic disk 103, that is, a predetermined track. The rotation accuracy can be tracked. The motion conversion mechanism unit 109 is configured to convert the rotational motion of the motor into the X-direction linear motion of the arm 105 by a crank mechanism.
[0019]
The arm 105 is slidably supported along the X direction by the cross roller table 111. At the tip of the arm 105, there are mounting portions 106a and 106b for attaching and detaching the U-shaped magnetic head assembly. Two magnetic head assemblies can be detachably held on the attachment portions 106a and 106b. For example, in this embodiment, the load beam 31 is inserted into the attachment portions 106a and 106b, and the screws 121a and 121b are screwed into the attachment portions 106a and 106b, thereby being detachably fixed to the attachment portions 106a and 106b. The sliders 11 and 11 face each other at a predetermined interval. An end terminal of the relay flexible wiring board 24 is connected to an input / output terminal of a writing / reading unit (R / W control unit) 131.
[0020]
With the magnetic head assembly mounted on the inspection apparatus 100 as described above, the inspection apparatus 100 drives the slider 11 to a predetermined track of the magnetic disk 103, and the writing / reading unit 131 uses the magnetic head of the slider 11. Writing / reading on the magnetic disk 103 is controlled. Further, the characteristics of the slider 11 and the like are analyzed by the analysis unit 132 from the signal read by the magnetic head of the slider 11, and the analysis result whether or not at least the predetermined characteristic is satisfied is displayed as a test result on the result display unit 133. indicate. The result may be recorded on a recording medium or printed as well as displayed.
[0021]
If it is determined that the slider 11 is defective, the slider 11 is peeled off from the flexure 21 and discarded, and the flexure 21 and the load beam 31 are reused as rework products.
[0022]
Below, one Embodiment of the peeling method of the slider 11 which is the characterizing part of this invention is described. The present embodiment is characterized in that a cut is formed in the bonding adhesive portion 25 before the slider 11 is peeled off from the flexure 21 and that this cut is formed by the ultrasonic cutter 40.
[0023]
First, as shown in FIG. 4, the flexure 21 is fixed by the flexure presser 26 on the rear end side of the slider 11 (the side opposite to the surface on which the bonding adhesive portion 25 is provided). An appropriate load for fixing the flexure 21 is given to the flexure presser 26.
[0024]
Next, as shown in FIG. 5, the ultrasonic cutter 40 is made substantially parallel to the surface of the flexure 21 with the cutting tool 40a facing the bonding adhesive portion 25 (actually about 10 ° inclined). By moving in the direction of the arrow, a cut portion α (FIG. 6) is formed in the bonding adhesion portion 25. As shown in FIG. 6, the cut portion α is preferably formed in the vicinity of the boundary surface between the bonding bonded portion 25 and the flexure 21. Instead of forming the cut portion α, the bonding adhesive portion 25 and the flexure 21 may be completely separated. Here, the reason why the ultrasonic cutter 40 is moved substantially parallel to the surface of the flexure 21 is to prevent the bonding adhesion portion 25 from remaining on the flexure 21 more than necessary. If the bonding adhesion portion 25 remains more than necessary, it may be difficult to mount a new (alternative) slider and the flexure 21 may not be reused.
[0025]
In the present embodiment, as the ultrasonic cutter 40, an ultrasonic cutter in which the cutting tool 40a is formed of a hard material such as cemented carbide, ruby, zirconia, or diamond is used.
[0026]
After the cut portion α is formed, as shown in FIG. 7, the slider 11 is erected with the side surface 11a interposed therebetween, and the slider 11 is pulled in the direction of the arrow shown in the drawing. Then, the bonding between the bonding bonding portion 25 and the flexure 21 is cut off from the cut portion α, and the slider 11 is peeled off from the flexure 21 together with the bonding bonding portion 25 while leaving a cut piece 25 ′ of the bonding bonding portion 25. At the time of the division, the stress applied to the flexure 21 and the flexible wiring boards 22 and 23 is suppressed by the presence of the cut portion α, and the flexure 21 is fixed by the flexure presser 26. The terminals 22a, 22b, 23a, and 23b are not peeled off together with the bonding adhesive portion 25, and the flexure 21 is not deformed. FIG. 8 shows the surface of the flexure after the slider 11 is peeled according to the above process.
[0027]
As described above, according to the present embodiment, the cut portion α is formed in the bonding adhesion portion 25 by the ultrasonic cutter 40 in advance, and the slider 11 is peeled from the flexure 21 in a state where the cut portion α is formed. The slider 11 can be easily peeled from the flexure 21 without deforming the flexure 21 and the flexible wiring boards 22 and 23. Therefore, even when the slider 11 is determined to be defective in the dynamic characteristic inspection, the flexure 21 (including the flexible wiring boards 22 and 23) and the load beam 31 are reused by peeling the slider 11. And the yield is improved. FIG. 9 shows the surface of the flexure after the slider 11 is peeled off from the flexure 21 without forming a notch in the bonding bonding portion 25. In this case, the terminals 22a and 22b of the flexible wiring board 22 are peeled off, and the flexible wiring board 22 and the flexure 21 cannot be reused.
[0028]
In the present embodiment, the bonding bonding portion 25 is formed of Au. However, when the bonding bonding portion 25 is formed of a metal material having malleability and ductility such as Au, Ag, Cu, or solder, the malleability is high. In addition, due to ductility, a normal cutter that does not use ultrasonic vibration cannot form the cut portion α in the bonding adhesion portion 25. On the other hand, when the ultrasonic cutter 40 is used as in the present embodiment, the cut portion α can be easily formed in the bonding adhesion portion 25 made of a metal material having malleability and ductility. The reason why the metal material that is simply crushed without applying the force required for cutting even when attempting to cut at a normal speed is easily cut by the ultrasonic cutter 40 is that the cutting tool 40a that vibrates ultrasonically is fast. This is probably because the metal material cannot follow the movement (it does not move due to inertia), and a sufficient force is applied between the cutting tool 40a and the metal material. The present invention is particularly effective for a magnetic head assembly provided with a bonding adhesion portion 25 made of a metal material having malleability and ductility such as Au, Ag, Cu, or solder. Of course, the present invention can also be applied to a magnetic head assembly in which the bonding adhesion portion 25 is formed of a metal material other than Au, Ag, Cu, or solder.
[0029]
Further, in this embodiment, the slider 11 is fixed to the flexure 21 only by the bonding adhesive portion 25. However, in reality, there are many cases where an auxiliary adhesive portion (mainly resin bonding) is provided in addition to the bonding adhesive portion 25. . In the case where such an auxiliary bonding portion is provided, it is preferable to weaken the bonding strength with the flexure 21 by heating the auxiliary bonding portion before the slider 11 is peeled off. More preferably, the heating step is performed after the cut portion α is formed.
[0030]
As mentioned above, although this invention was demonstrated based on illustration embodiment, this invention can be changed unless it deviates from the range, and is not limited to illustration embodiment.
[0031]
【The invention's effect】
According to the slider peeling method of the present invention, a notch is formed in advance in the bonding bonding portion of the slider to weaken the bonding strength between the bonding bonding portion and the flexure, so that the flexure and the wiring pattern on the flexure surface can be deformed. Therefore, the slider can be easily separated from the flexure, and the flexure (including the flexible wiring board) and the load beam can be reused.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of a magnetic head assembly (completed state), which is a target for carrying out a slider peeling method according to the present invention.
FIG. 2 is an enlarged plan view showing a peripheral portion of the slider in FIG. 1;
FIG. 3 is a schematic perspective view showing an embodiment of an inspection apparatus used for dynamic characteristic inspection of a magnetic head assembly.
FIG. 4 is a perspective view showing one step of a slider peeling method according to the present invention.
5A is a perspective view and FIG. 5B is a cross-sectional view showing a step subsequent to the step shown in FIG. 4;
6 is a cross-sectional view showing a cut portion formed in the step shown in FIG. 5. FIG.
7 is a perspective view showing a step subsequent to the step shown in FIG. 5. FIG.
8 is a plan view showing the surface of the flexure after the slider is peeled off by the process shown in FIG.
FIG. 9 is a plan view showing the surface of the flexure after the slider is peeled off by a conventional peeling method.
FIG. 10 is a perspective view showing a conventional magnetic head assembly.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Magnetic head assembly 11 Slider 21 Flexure 22 23 Flexible wiring board (FPC)
22a 23a 22b 23b Terminal portion 24 Relay flexible wiring board 25 Bonding adhesive portion 25 ′ Cutting piece 26 Flexure presser 31 Load beam 40 Ultrasonic cutter 40a Cutting tool 100 Inspection device α Cutting portion

Claims (5)

A slider provided integrally with an electromagnetism conversion element, a flexible flexure in which the slider is bonded by a bonding adhesive portion made of Au, Ag, or Cu, and bonded to the surface of the flexure. In a magnetic head assembly comprising a flexible wiring board electrically connected to the electro-magnetic transducer through a section, the slider is peeled off from the flexure when the slider has poor characteristics,
Pressing and fixing the flexure on the side of the slider opposite to the side on which the bonding adhesive portion is provided; and
In a state where the flexure is fixed , forming an incision in the bonding adhesive portion with an ultrasonic cutter , leaving a bonding portion between the bonding adhesive portion and the flexure at the tip of the incision portion ;
With the flexure fixed, together with the bonding adhesive part, the slider is raised with the tip of the notch formed in the bonding adhesive part as a fulcrum, and the slider is pulled away from the bonding adhesive part. Peeling from the flexure;
A slider peeling method comprising: 2. The slider peeling method according to claim 1 , wherein in the step of peeling off the slider, a part of the bonding adhesion portion is left on the flexible wiring board, and the slider and the bonding adhesion portion are peeled off from the flexure. . 3. The slider peeling method according to claim 1, wherein the ultrasonic cutter is moved substantially parallel to the surface of the flexure to form a cut in the bonding adhesion portion. 4. The slider peeling method according to any one of claims 1 to 3, wherein the slider is bonded with a resin adhesive separately from the bonding bonding portion, and at least after the notch forming step by the ultrasonic cutter, The slider peeling method which has a heating process which reduces the adhesive strength of a resin adhesive. The slider peeling method according to any one of claims 1 to 4, wherein the ultrasonic cutter uses an ultrasonic cutter having a blade formed of cemented carbide, ruby, zirconia, or diamond.

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