JPH11259827A - Inspection method for magnetic head and inspection device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an MR head inside a magnetic head assembly from being destroyed by static electricity when the terminal of the probe of a DCR measurement device is brought into contact with the measurement part of a lead at the time of measuring the characteristics of the magnetic head. SOLUTION: In this inspection method, a holder 18a formed by a semiconductor (surface resistance=1×10<6> -1×10<12> Ω/square) is connected to the ground G by closing a switch SW1, the terminal 9 and the DCR measurement device are interrupted by opening the switch SW2 and then, a magnetic head unit 1 and the lead 5 are mounted inside an installation part 12A. After the elapse of prescribed time, in the state of opening the switch SW1 and closing the switch SW2, the characteristics of the magnetic head unit 1 are measured. By performing disconnection by such as procedure, the MR head is prevented from being destroyed by the static electricity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a magnetic head on which an MR head or the like is mounted, and more particularly to a method for inspecting a magnetic head which prevents the MR head from being destroyed by static electricity in measurement of the MR head. It relates to the inspection device.

[0002]

2. Description of the Related Art FIG. 2 is a perspective view showing a conventional magnetic head unit and a magnetic head measuring means. In the magnetic head unit 1 shown in FIG. 2, a slider 3 is provided on the lower surface side (Z2 side) of the distal end (X1 side) of a leaf spring 2 made of a very thin plate material such as stainless steel. The slider 3 includes a read-only thin-film magnetic head (MR head) 3A.
This is a composite type thin-film magnetic head including a recording-only inductive head 3B.

The X2 side of the leaf spring 2 is a fixing portion 2a. A lead 5 such as a flexible printed board extending in the X2 direction in the figure is fixedly provided on the lower surface side of the fixing portion 2a. On the lead 5, four pattern lines are formed in parallel and connected to the input and output terminals of the thin film magnetic head (MR head) 3A and the inductive head 3B of the slider 3, respectively. X2 of lead 5
A measuring portion 5A is formed at the end on the side. The measuring section 5A is composed of four square holes 5a, 5b, 5c and 5d in which a copper foil or the like is exposed on the surface of the lead 5 and holes are formed in the center thereof. Each of these square holes 5a, 5
b, 5c and 5d are formed at a predetermined size and at predetermined intervals. Then, each pattern line of the lead 5 is connected to each of the square holes 5a, 5b, 5c and 5d of the measuring section 5A.
Connected to each other. That is, for example, the input terminal and the output terminal of the MR head 3A are connected to the square hole 5a and the square hole 5b, respectively, and the input terminal and the output terminal of the inductive head 3B are connected to the square hole 5c and the square hole 5d via the pattern wire of the lead 5, respectively. It is connected to the.

FIG. 2 shows a dedicated probe 8 for performing an electric resistance of a DC component between an input terminal and an output terminal of the MR head 3A or the inductive head 3B. The dedicated probe 8 is connected to the measuring section 5A of the lead 5.
Has terminals 9 (9a, 9b, 9c and 9d) which can be respectively inserted into the square holes 5a, 5b, 5c and 5d, and is embedded in a holder 8a made of an insulator. (Z1 direction). The lead wires 10 output from the terminals 9 extend to the other end face side of the holder 8a, respectively.
Connected to R measuring device 7. The DCR measuring device 7
Is a so-called digital volt meter, etc.
Normally, when a resistor is connected to both ends of a pair of probes,
A minute constant current (for example, 1 mA) is passed, a voltage drop during the measurement is measured, and the voltage value is converted to display the DC resistance value of the resistor. By using the dedicated probe 8, before the magnetic head unit 1 is delivered,
Or, in some cases, after delivery, the DC resistance of the MR head 3A and the inductive head 3B is measured.

[0005]

However, when the measurement is performed using the above-mentioned dedicated probe, there are the following problems. That is, the terminal 9 of the dedicated probe 8 is
When inserted into each square hole 5a, 5b, 5c and 5d of A,
Accidents such as burning of the MR head 3A occurred frequently.

[0006] This cause is considered to be caused by static electricity. That is, the lead 5 has a plurality of pattern lines formed in an insulating film of polyimide or the like. However, the insulating film itself is easily charged by static electricity.
It may be charged to a high potential of about 0 to 300V.
When such charging occurs, each pattern line is also exposed to a high potential, so that the potential of the input terminal and output terminal of the MR head 3A or the inductive head 3B directly connected to this is viewed from the ground side. Also has an extremely high potential. On the other hand, the DCR measuring device normally floats from the ground potential, but still has a high potential difference between each of the pattern lines. Therefore, in such a state, the terminal 9 of the dedicated probe 8 is connected to each of the square holes 5a, 5b,
When inserted into 5c and 5d, electrons move during this time, and a current of several hundred mA or more may flow transiently.

This is because the terminal 9 is inserted into the measuring portion 5A, that is, the terminal 9a is in the square hole 5a, the terminal 9b is in the square hole 5b, the terminal 9c is in the square hole 5c, and the terminal 9d is in the square hole 5d. When they are respectively inserted, it appears that they are inserted at the same time, but strictly speaking, there may be some time lag between the terminals 9. For example, when the terminal 9a is inserted into the square hole 5a and conducts with the input terminal of the MR head 3A, the terminal 9b may not yet conduct with the output terminal of the MR head 3A. A large current flows transiently due to the potential difference therebetween. At this time, the output terminal side is also electrically connected to the terminal 9a via the MR head 3A and the input terminal, so that a large current transiently occurs in the MR head 3A and the input terminal due to the potential difference between the terminal 9a and the output terminal. . In particular, when the current flowing through the MR head is a sense current (about several mA to about 15 mA) or more, there is a problem that the MR head 3A is burned out.

Further, static electricity is generated not only on the lead 5 side but also on the dedicated probe 8 side. That is, the dedicated probe 8
The lead wire 10 connected to the DCR measurement device 7 is formed by twisting a plurality of lead wires 10 (four in the above case) covered with an insulator, so that triboelectric charging of each coating is performed. For example, electrostatic induction is likely to occur. Thus, for example, if a positive induced charge is accumulated in the coating and charged to the (+) potential, the (-)
Electrons are attracted to the outer peripheral surface side of the conductor portion 7A. As a result, the inside of the conductor becomes deficient in (-) electrons, so that an induced polarization occurs in which the center of the conductor has a (+) potential. And each terminal 9 connected in such a state,
Since there is a potential difference between the lead 5 and the pattern line, when both are connected, electrons move between them.
As described above, a large current of several hundred mA or more transiently flows and M
Burn-in occurs in the R head 3A. In particular, when the potential of the central portion of the conductive wire is generated in the opposite direction to the potential of the pattern line, the potential difference between the two is further increased, so that a larger current is generated.

The connection between the magnetic head unit 1 and the hard disk is made at a connection terminal 5B closer to the magnetic head unit 1 than the measuring unit 5A. In other words, after the measurement of the DC resistance, the measuring section 5A of the lead 5 becomes unnecessary, so that it is necessary to cut off the vicinity of the line 6-6 in the drawing before assembling the hard disk or the like.
For this cutting, a sharp metal cutter or the like is used. Then, when the cutter cuts the pattern line of the lead 5 after the measurement, a large current flows between the pattern line and the cutter due to a potential difference between the pattern line and the cutter as described above, and the MR head 3A is burned. In this case, burnout occurs due to static electricity generated during the time from the measurement of the DC resistance until the disconnection. Accordingly, it is necessary to cut the lead 5 immediately after measurement before new static electricity is generated in the lead 5.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a method of inspecting a magnetic head in which the MR head is not burned out when measuring the DC resistance of the MR head. .

Another object of the present invention is to provide a method of inspecting a magnetic head in which an MR head is not burned when cutting a lead such as a flexible printed circuit board or a lead wire.

It is a further object of the present invention to provide a magnetic head inspection apparatus capable of simultaneously measuring the DC resistance of the MR head and cutting the leads.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a method for inspecting a magnetic head having a thin-film element and provided with a lead connected to the thin-film element, wherein a holder provided on a base is grounded. Connecting the terminal provided on the holder to the DCR measuring device, fixing the magnetic head to the base, and connecting a measuring part of a lead extending from the magnetic head to the terminal. Disconnecting the holder from the ground after a predetermined time elapses, and connecting the terminal to a DCR measuring device to
And a step of measuring CR.

In the present invention, when the holder is connected to the ground, as shown in FIG. 1, each pattern line is connected to the ground G via the terminal 9, the holder 18a, the output line 13, and the switch SW1, such as the square hole 5a. . At the same time, the DCR measuring device 7
The connection between the terminal and each terminal 5a is interrupted by the switch 2. Therefore, when the magnetic head and the lead 5 are mounted on the base 12 and the measuring unit is connected to the terminal, the movement of the electrons caused by the potential difference of each pattern line of the lead caused by the electrostatic charge is caused by the above-mentioned pattern line. , Square hole 5a, etc.
The connection can be made to the ground G via the terminal 9, the holder 18a, the output line 13, and the switch SW1. Therefore,
By making the resistance value of the holder high, the movement of electrons can be decelerated, so that a large current can be prevented from flowing during this time. In addition, the measurement of the magnetic head can be performed in a state where a small current flows slowly over time and the potential difference between the pattern lines is almost zero. Therefore, when the terminal is connected to the DCR measuring device again, the potential difference between the pattern line and the DCR measuring device becomes almost zero, and it is possible to make it difficult for electrons to move rapidly during this period. That is, the terminal is again set to D
When connected to a CR measurement device, it is possible to prevent a large current from flowing. Therefore, since the current flowing through the pattern line itself can be reduced, it is possible to prevent the MR head from burning.

In the above, it is preferable that the method further comprises a step of connecting the terminal to a DCR measuring device, measuring the DCR of the thin film element, and then cutting the measuring portion from the lead.

Since the lead is cut immediately after measuring the characteristics of the magnetic head, it is possible to make it difficult for the lead to be charged with static electricity generated during the period from the measurement to the cutting. Therefore, abrupt movement of electrons is less likely to occur between the pattern line and the cutter when cutting, so that a large current is not generated.

Further, it is preferable that the holder is made of a semiconductive material having a surface resistance in the range of 1 × 10 ⁶ to 1 × 10 ¹² (Ω / square).

By setting the surface resistance of the holder within this range, it is possible to make the peak value of the transient current generated when the measuring unit is connected to the terminal equal to or less than the sense current. Therefore, the current flowing through the MR head itself is reduced, and thus the burn-in of the MR head can be prevented.

The inspection apparatus for a magnetic head comprises an installation section on which a magnetic head having a thin film element is installed, a terminal connected to a measurement section provided on a lead connected to the thin film element, and a holding section for holding the terminal. Holder, the terminal and the DCR
A switch for connecting and disconnecting the measuring device and a switch for connecting and disconnecting the holder and the ground are provided.

In the above, it is preferable to use a DCR measuring device having a cutter for measuring the DCR of the thin film element and then cutting the lead to separate the measuring portion.

By mounting a magnetic head having a lead on this magnetic head inspection apparatus, it is possible to perform from the measurement of the magnetic head by the above-described method to cutting of a part (measurement part) of the lead in a short time. . That is, the measurement of the magnetic head can be reliably performed without burning the MR head, and the lead can be cut.

The holder has a surface resistance of 1 × 10 ⁶ (Ω).
/ Square) to 1 × 10 ¹² (Ω / square)
Are preferably made of a semiconductor in the range of

As a result, electrons can be moved slowly, so that generation of a large current can be suppressed, and the potential difference between the pattern line and the ground or the DCR measuring device gradually approaches zero. Can be. Therefore, after a lapse of a predetermined time, that is, after the potential difference reaches zero, it is possible to prevent the MR head from burning out when the measurement is performed by the DCR measuring device or the lead is cut.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an inspection apparatus for measuring a magnetic head unit and cutting a lead.
The magnetic head unit 1 is the same as that shown in FIG. 2 described above, and includes a slider 3 having a thin-film magnetic head (MR head) 3A dedicated to reproduction and an inductive head 3B dedicated to recording at the tip of a leaf spring 2. Is provided. A lead 5 made of a flexible printed circuit board or the like connected to the input terminal and the output terminal (both not shown) of the MR head 3A and the inductive head 3B extends from one lower surface side of the fixed portion 2a. Part 5
A is formed. Note that the lead 5 may be a normal lead wire other than the flexible printed circuit board. The measuring unit 5A is composed of square holes 5a, 5b, 5c and 5d in which a hole is formed in the center of the copper foil exposed on the surface of the lead 5,
These are connected to input terminals and output terminals of the MR head 3A and the inductive head 3B, respectively. Also, between the measuring unit 5A and the magnetic head unit,
A connection terminal 5B for connecting to an actual hard disk is provided.

Reference numeral 11 denotes an inspection device, which is mainly a base 12
And a cutter C. An installation portion 12A is formed on the base 12, and the installation portion 12A includes a first fitting groove 12a in which the magnetic head unit is housed, a second fitting groove 12b in which the lead 5 is housed, and a lead 5. And the third fitting groove 12c in which only the measuring section 5A is stored. Then, these mounting portions 12A (the first, second and third fitting grooves 12a, 12b and 12
The magnetic head unit 1 and the lead 5 can be accommodated in almost the same shape in c). A receiving portion 12B extending between the second fitting groove 12b and the third fitting groove 12c, that is, between the measuring portion 5A and the connection terminal 5B, extends in a direction perpendicular to the direction in which the lead 5 extends. Is formed. The cutting edge of the cutter C is narrowly inserted into the receiving portion 12B.

The cutter C is a sharp metal blade made of steel or the like, is rotatably fixed at a fulcrum (not shown), and the receiving portion 12B is located within the range of rotation. The lead 5 can be cut by lowering the cutter C with the lead 5 mounted in the second fitting groove 12b and the third fitting groove 12c. In addition, beside the inspection device 11, there is a D for measuring the DC resistance of the MR head 3A and the inductive head 3B.
A CR measuring device 7 is provided, and a measuring probe 18 of the DCR measuring device is embedded in the third fitting groove 12 c of the base 12. The measurement probe 18 is attached to the holder 1
Terminals 9 (9a, 9b, 9c and 9d) are buried in the inside of 8a at the same intervals as the square holes 5a, 5b, 5c and 5d, and the holder 18a is inserted from the third fitting groove 12c. Exposed and each of the terminals 9a, 9b, 9c
And 9d project upward in the figure. This holder 1
8a has a surface resistance of 1 × 10 ⁶ to 1 × 10 ¹² (Ω
/ Square) of a semiconductive material.

The semiconductive material is made of, for example, an ion conductor, a conductive polymer, a conductive filler, an ion conductive polymer, or the like. Examples of the ionic conductor include ZrO ₂ —Y ₂ O ₃ , Bi ₂ O ₃ —Y ₂ O ₃ , Pb
Cl ₂ , Li ₁₄ Mg (GeO ₄ ) ₄ , PbF ₂ , Li ₃ N
(Single crystal), Na-β-alumina (polycrystal), 7CuB
r · C ₆ H ₁₂ N ₄ CH ₃ Br, H ₃ PW ₁₂ O ₄₀ · 29H
₂ O, Na-β-alumina (single crystal), RbAg ₄ I _{5, and the} like, and conductive polymers such as polyacetylene, poly-p-phenylenevinylene, poly-2.5-tunylenevinylene, and poly-p -Phenylene, polypyrrole, polythiophene, polyaniline, polyisothianaphthene,
Polyberinaphthalene or the like can be used. Further, as the conductive filler, for example, a compound obtained by combining a metal matrix filler such as carbon black, metal powder, or metal-plated inorganic substance with a plastic matrix can be used. As the ion conductive polymer, for example, polyethylene oxide + LiClO 2 can be used. ₄ (12: 1), Crosslinked polyethylene oxide + LiClO by gamma irradiation
₄ (1: 8), polypropylene + LiCF ₃ SO ₃ (9:
1), polyethylene adipic acid derivative + LiCF ₃ S
O ₃ (4: 1), polyethylene succinic acid derivative + Li
B ¢ ₄ (6: 1), polyphosphazene (ME7P) +
LiCF ₂ SO ₃ (16: 1), crosslinked polyphosphene (1XMP) + LiCF ₃ SO ₃ (32: 1), linear complex polysiloxane (PMM57) + LiClO ₄ (25:
1) unsaturated urethane is allowed triol polyethylene oxide + LiClO ₄ crosslinking (50: 1), PEO- PPO-P which was crosslinked urethane having three functional groups
It is possible to use EO block copolymer + LiClO ₄ (20: 1) or the like.

The output line 13 is connected to the holder 18a, and is connected to the ground G via the switch SW1. On the other hand, terminals 9a, 9b, 9c
And the four lead wires 10 connected to 9d are output to the outside of the base 12 by being twisted or by a flexible printed circuit board or the like. The lead wire 10 is connected to a DCR measuring device via a switch SW2.

Hereinafter, a method of measuring and cutting the magnetic head will be described. Before the magnetic head unit 1 is housed in the installation portion 12A of the base 12 shown in FIG. 1, the switch SW1 is closed and the holder 18a is connected to the ground G. At the same time, the switch SW2 is opened, and the terminal 9 side and the DC
The connection with the R measuring device 7 is disconnected. Thereby, the lead wire 10 is connected to the holder 18a, the output line 13, and the switch SW.
1 to the ground G. Therefore,
If the above-mentioned conductive wire has an induced polarization with a potential of (+) at the center, the (−) electrons are transferred from the ground G to the switch SW.
The current moves in the order of 1 → output line 13 → holder 18a, and the current flows in the opposite direction, so that the terminals 9a, 9b, 9c and 9d have the potential of the ground G. In the case where the induced polarization at which the central portion of the conductor is at the (-) potential occurs, electrons move in the opposite direction and current flows. Similarly, terminals 9a, 9b, 9c and 9d are connected to terminals 9a, 9b, 9c and 9d. It becomes the potential of the earth G.

Next, the magnetic head unit 1 is housed in the installation portion 12A of the base 12. At this time, the measuring portion 5A of the lead 5 is fitted into the third fitting groove 12c,
a, 9b, 9c and 9d have square holes 5a, 5
b, 5c and 5d are extrapolated and each is electrically connected. At this time, if the lead is charged by static electricity, the potential difference between the square holes 5a, 5b, 5c and 5d (panned wires) and the terminals 9a, 9b and 9c usually causes the electrons to be discharged. Movement occurs and current is generated. However, since the lead wire 10 is disconnected, electrons move between the terminal 9, the holder 18a, the output line 13, and the ground G via the switch SW1.
Here, the holder 18a is formed of a semiconductive material as described above, and has a surface resistance of 1 × 10 ⁶ to 1 × 10 ^6.
Since it is within the range of ¹² (Ω / square), rapid movement of electrons is suppressed, and the electrons can be slowly moved over time. Therefore, the square holes 5a, 5b, 5c and 5
It is possible to prevent a large transient current from occurring when d comes into contact with the terminals 9a, 9b, 9c and 9d.

Then, a small current is applied for a sufficient time, and when the potential difference between the square hole and the terminal becomes substantially zero, the switch SW1 is opened and the switch SW2 is closed, so that the MR head 3A and the inductive head 3B Can be measured.

After the DC resistance measurement, the lead can be cut by immediately lowering the cutter. At this time, since it is not necessary to move the magnetic head unit 1 until the cutting after the measurement as in the related art, it is possible to prevent static electricity from being charged on the lead 5 during this time. Therefore, since the potential difference between the pattern line of the lead 5 and the cutter C is reduced, the movement of the electric charge at the time of cutting is prevented, and a large current does not occur. Therefore, since a large current does not occur between the input terminal and the output terminal of the MR head, burning of the MR head can be prevented.

The cutter C is preferably connected to the earth G via a semiconductor. For example,
Even when the cutter C is used without performing the switching operation, the electrons move through the semiconductor, so that there is no rapid movement of the electrons. Therefore, generation of a large current can be prevented.

[0034]

According to the present invention, the DC resistance of a magnetic head can be measured without burning the MR head due to static electricity.

Also, without burning out the MR head,
A part of the lead can be cut.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an inspection apparatus for measuring and cutting a magnetic head according to the present invention;

FIG. 2 is a perspective view showing a conventional magnetic head unit and a measuring unit of the magnetic head;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic head unit 5 Lead 5A Measuring part 5a, 5b, 5c, 5d 5B Connection terminal 7 DCR measuring device 9, 9a, 9b, 9c, 9d Terminal 11 Inspection device 12 Base 12A Installation part 12a First fitting groove 12b Second fitting groove 12c Third fitting groove 12B Receiver 18 Measurement probe 18a Holder SW1, SW2 Switch G Ground

Claims (6)

[Claims] 1. A method for inspecting a magnetic head having a thin-film element and provided with a lead connected to the thin-film element, the method comprising: connecting a holder provided on a base to ground; Disconnecting the terminal provided from the DCR measuring device, fixing the magnetic head to the base, and connecting the measuring portion of the lead extending from the magnetic head to the terminal, and after a predetermined time elapses A method for inspecting a magnetic head, comprising: a step of disconnecting a holder from a ground; and a step of connecting the terminal to a DCR measuring device to measure DCR of a thin film element. 2. The magnetic head inspection method according to claim 1, further comprising the step of connecting the terminal to a DCR measuring device, measuring the DCR of the thin film element, and then cutting the measuring portion from the lead. 3. The magnetic head inspection method according to claim 1, wherein the holder is made of a semiconductor having a surface resistance in a range of 1 × 10 ⁶ to 1 × 10 ¹² (Ω / square). 4. A mounting section on which a magnetic head having a thin-film element is installed, a terminal connected to a measuring section provided on a lead connected to the thin-film element, a holder for holding the terminal, An inspection apparatus for a magnetic head, comprising: a switch for connecting and disconnecting a DCR measurement device; and a switch for connecting and disconnecting the holder and ground. 5. A DCR measuring device, wherein the DC of a thin film element is measured.
5. The magnetic head inspection apparatus according to claim 4, further comprising a cutter that cuts a lead and separates a measurement portion after measuring R. 6. The magnetic head inspection apparatus according to claim 4, wherein the holder is made of a semiconductor having a surface resistance in a range of 1 × 10 ⁶ to 1 × 10 ¹² (Ω / square).