JPH0760497B2 - Magnetic head device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A Industrial Field B Outline of the Invention C Conventional Technology D Problems to be Solved by the Invention E Means for Solving Problems (Fig. 1) F Action G Example (Fig. 1) H Invention Effect A Industrial field of application The present invention relates to a magnetic head device suitable for application to, for example, a magnetic head device for a hard disk.

B Outline of the Invention A magnetic head device according to the present invention includes first and second same head elements formed on a common head substrate, a common bonding pad formed on a common head substrate,
A first head formed on a common head substrate and connecting between the first and second head elements and a common bonding pad;
And a second connection conductor, and the first and second connection conductors are connected so that only one effective head element of the first and second head elements is connected to a common bonding pad. Since one side is cut, the number of bonding pads can be reduced by half and the area can be increased.

C Conventional Technology A conventional magnetic head device for a hard disk (composite magnetic head device) will be described below with reference to FIGS. 2 to 7.

FIG. 2 shows this magnetic head device as a whole, and the head substrate (41) is common to the U-shaped end surface of the slider (5) made of alumina, titanium or the like, and data is sequentially read from both outer sides to the inner side. Magnetic head for signal recording / reproduction (1)
[(1 _1), (1 _2)], the tracking signal reproducing magnetic head (2) [(2 _1), (2 _2)] and an initial tracking signal recording magnetic head (3) [(3 _1), ( 3 ₂ )] is formed in line symmetry at the lower edges of the pair of rail portions (5R ₁ ) and (5R ₂ ).

Each magnetic head (1 ₁ ), (1 ₂ ); (2 ₁ ), (2 ₂ );
(3 ₁ ) and (3 ₂ ) are corresponding bonding pads BP ₁ and BP respectively corresponding to the required number of connection conductive layers L ₁ and L _2.
Connected to ₂ . Then, these magnetic heads (1 ₁ ), (1
₂ ); (2 ₁ ), (2 ₂ ); (3 ₁ ) and (3 ₂ ) are connected to the recording or reproducing circuit via the bonding pad BP ₁ or BP ₂ .

FIG. 3 is a pair of magnetic head devices having the configuration shown in FIG.
Rotating magnetic recording media (hard disk) for MHD ₁ and MHD ₂
The case where the magnetic layers (4b) and (4c) on both sides of (4) are arranged so as to face each other is shown. Incidentally, (4a) is a substrate of the rotating magnetic recording medium (4). In this case, in the magnetic head device MHD ₁ , the magnetic heads (1 ₁ ), (2 ₁ ), (3 ₁ ) are used, and the magnetic heads (1 ₂ ), (2 ₂ ), (3 ₂ ) are not used. or,
In the magnetic head device MHD ₂ , the magnetic heads (1 ₂ ), (2 ₂ ),
(3 ₂ ) is used, and magnetic heads (1 ₁ ), (2 ₁ ), (3 ₁ )
Is not used.

Next, with reference to FIGS. 4 to 7, detailed structure of the magnetic head device (composite magnetic head device) shown in FIG.
No. 60-87757). Reference numeral (4) is a hard disk as a rotating magnetic recording medium, and magnetic layers (4b), (4b), (4b), such as γ-Fe ₂ O ₃ are provided on both sides of a base (4a) such as aluminum.
c) is deposited and formed. Here, recording / reproducing for one magnetic layer (4b) will be described. T indicates a concentric track formed on this magnetic layer (4b),
The width is W, the pitch is P, and the guard band width is G.
Therefore, P = W + G.

(1) is a magnetic head for recording / reproducing data signals, which can be a bulk magnetic head, but a thin film magnetic head is used here. This thin film magnetic head
It is composed of a composite magnetic head composed of an inductive magnetic head portion for recording and a magnetoresistive effect magnetic head portion for reproduction.

(2a) and (2b) are a pair of tracking signal reproducing magnetic heads having the same trace width, which can be a bulk magnetic head or an inductive thin film magnetic head, but here a magnetoresistive thin film magnetic head is used. is doing. (3) is a magnetic head for recording an initial tracking signal, which can be a bulk magnetic head, but here an induction type thin film magnetic head is adopted, and a plurality of head parts (3a in this example) are used. , (3b), (3c). Incidentally, each of the head portions may be composed of a single magnetic head.

The trace width of the magnetic head (1) for recording / reproducing data signals,
In particular, the trace width during recording (which is approximately equal to the gap width) is selected to be equal to the width W of the track T to be recorded and formed, but it may be slightly different. The trace width of the magnetic heads (2a) and (2b) for tracking signal reproduction (which is approximately equal to the gap width) is h, the interval between them is S, and both side edges of each trace of both magnetic heads (2a) and (2b) The interval between them is H. As an example of these dimensional relationships, H is equal to W and h and S are equal to G, so H = W = 3G. For example, G, h, S is 4.5μm, W, H is 13.5μ
m.

This magnetic head for tracking signal reproduction (2a), (2b)
Each of the above dimensions of
Must be less than or equal to G, h must be greater than or equal to G to prevent saturation, and the magnetic head (2
When the middle point between a) and (2b) comes to the middle of the adjacent track T, the difference between the two reproduction outputs becomes 0, and in the other parts, it becomes a value different from 0, that is, the dead zone does not occur. In order to do so, S must be less than or equal to G. Although the crosstalk prohibition condition and the saturation prohibition condition are inconsistent in manufacturing, respecting the crosstalk prohibition condition,
Let h be G or less.

Next, the dimensions of the initial tracking signal recording magnetic head (3) will be described. Each head part (3a), (3b), (3c)
Is selected to be equal to the pitch P of the track T.
Further, the trace width of the head portions (3a), (3b), (3c) (which is approximately equal to the gap width) is made equal to the width W of the track T, but it may be slightly different.

Next, the positional relationship between the magnetic heads (1), (2a), (2b) and (3) will be described. In FIG. 4, the horizontal axis x represents one radius of the rotating magnetic recording medium (4), and the direction from the center to the outer periphery is positive. Here, the data signal recording / reproducing magnetic head (1) is on the outer peripheral side of the rotating magnetic recording medium (4), the initial tracking signal recording magnetic head (3) is on the inner peripheral side, and the tracking signal reproducing magnetic head is in the middle thereof. The magnetic heads (2a) and (2b) are located. It is desirable that the data signal recording / reproducing magnetic head (1) is located on the outer peripheral side of the rotating magnetic recording medium (4) with respect to the initial tracking signal recording magnetic head (3) for recording the data signal.

In FIG. 4, the centers of the gaps of the magnetic heads (1), (2), and (3) and the positions of both ends thereof are shown on the x-axis. In this case, the origin of the x-axis is at the center of the gap of the data signal recording / reproducing magnetic head (1). In general, the center of the trace width of the data signal recording / reproducing magnetic head (1), that is, the origin 0, and the center between the traces of the pair of tracking signal reproducing magnetic heads (2a) and (2b), that is, both The distance in the track arrangement direction from the center of the gap is (n + 1/2) P (where n = 1,2,3, ...), where n = 2 and (5/2) P This is the case. The center of the trace of the magnetic head for recording / reproducing the data signal (1) (center of the gap) and the center of each trace of the magnetic heads for reproducing the tracking signal (2a), (2b) (center of the gap) The number (n) of the head portions (3a), (3b) and (3c) of the initial tracking signal recording magnetic head (3) according to the n value of the distance (n + 1/2) P in the track arrangement direction between
+1) is determined and is 3 in this example.

In the initial tracking signal recording magnetic head (3), the center of the gap of the head portion (3a) on the side of the tracking signal reproducing magnetic head (2b), that is, the center of the trace width is set to x ₀ , and the other head portion is set. The center of the gap in (3b) and (3c), that is, the center of the trace width and the position of its end are x
It is shown on the axis.

Next, the operation of this composite magnetic head device will be described. When a data signal is recorded on the rotating magnetic recording medium (4), an arbitrary digital signal is supplied to the initial tracking signal recording magnetic head (3) in advance before the data signal is recorded on the rotating magnetic recording medium (4). Recording is performed so that three reference tracks are simultaneously formed on the circumferential side. Then, the tracking signal reproducing magnetic heads (2a) and (2b) are reproduced across the reference track on the inner circumference side of the rotating magnetic recording medium (4) so that the difference between the reproduction outputs becomes zero. The position of the magnetic head is controlled, and at the same time, the data signal is recorded by the data signal recording / reproducing magnetic head (1). Thereafter, the tracks formed by the data signal recording / reproducing magnetic head (1) are similarly reproduced by the tracking signal reproducing magnetic heads (2a) and (2b), and at the same time, the data signal recording / reproducing magnetic head ( The data signal is recorded in 1).

During reproduction, the data signal recording / reproducing magnetic head (1) reproduces a data signal of an arbitrary track while tracking is performed by the tracking signal reproducing magnetic heads (2a) and (2b).

Furthermore, the tracking signal reproducing magnetic heads (2a), (2
The reproduction signal from b) is supplied to each envelope detection circuit through each amplifier and filter (not shown), and each detection output is supplied to the differential amplifier to obtain an output. The output of this differential amplifier becomes a tracking error signal during track scanning, and becomes a signal indicating the radial position of the rotating magnetic recording medium (4) when crossing a track. During track scanning, the radial position of the magnetic heads (1), (2) and (3) on the rotating magnetic recording medium is controlled by this tracking error signal. Further, the differential output is supplied to the differentiating circuit and the zero-cross detector. The output of the differentiating circuit becomes a signal indicating the scanning speed of the magnetic head when it crosses a track. The output of the zero-cross detector is a signal indicative of a number related to the number of tracks that the magnetic head passes as it traverses the tracks.

When the data signal recording / reproducing magnetic head (1) is in the just tracking state with respect to the track T, the center between the traces of the tracking signal reproducing magnetic heads (2a), (2b) is located at the middle of the adjacent track T. Located in the center.

Next, the structure of each magnetic head described above will be described with reference to FIGS. 4 and 5 to 7. The structure of the data signal recording / reproducing magnetic head (1) is shown in FIG. 5, which is composed of a composite thin film magnetic head comprising an induction type magnetic head section and a magnetoresistive effect type magnetic head section as described above. That is, (1
1) is a magnetic substrate, on which various elements described later are formed though a non-magnetic insulating layer such as SiO ₂ though not shown. First, a magnetoresistive effect magnetic sensitive portion (14) is formed on the magnetic substrate (11) on the side of the gap g, and a magnetic layer (16) is provided so as to be magnetically coupled to this. The magnetic layer (16) is magnetically directly connected to a magnetic yoke (12) described later. Conductive layers (13) and (15) are arranged above and below the magnetic layer (16). Then, the magnetic yoke (12) is a magnetoresistive effect magnetic sensing section (14),
It is disposed on the magnetic layer (16) and the conductive layer (15), one end of which is magnetically directly connected to the magnetic substrate (11) and the other end of which is the gap g.
Located on the side.

During reproduction, the magnetic head (1) operates as a magnetoresistive effect magnetic head, and the conductive layer (1)
3) and (15), direct currents flowing in directions opposite to each other at right angles to the plane of the drawing in the figure are used, and the magnetoresistive effect magnetic sensing section (1
A bias magnetic field is applied to 4) to increase the sensitivity and reproduce the data signal. At the time of recording, this magnetic head (1) operates as an inductive magnetic head, and the conductive layer (1)
In 3) and (15), apply recording currents in the same direction at right angles to the paper surface. In this case, almost no magnetic flux passes through the magnetic layer (16). In FIG. 4, (14a) and (14b) are connection conductive layers derived from the magnetoresistive effect magnetic sensing section (14),
(15a) and (15b) are connection conductive layers derived from the conductive layer (15), and (13a) and (13b) are connection conductive layers derived from the conductive layer (13).

Next, magnetic heads for tracking signal reproduction (2a), (2b)
The structure will be described with reference to FIGS. 4 and 6. This is composed of the magnetoresistive thin film magnetic head as described above. Each element is formed on a magnetic substrate (21) via a non-magnetic insulating layer such as SiO ₂ . A yoke is formed on the magnetic substrate (21) and is composed of two yoke portions (22a) and (22b) arranged at a predetermined interval. A gap g is formed between one end of the one yoke portion (22a) and one end of the magnetic substrate (21). And the magnetic yokes (22a), (22b)
And the magnetic resistance effect magnetic sensing section (24) between the magnetic base (21).
And a bias conductive layer (23) thereunder. A bias magnetic field is applied to the magnetoresistive effect magnetic sensing section (24) so that the sensitivity is increased by applying a direct current to the bias conductive layer (23). In addition, in FIG. 4, (24a), (24b),
Reference numeral (24c) is a connecting conductive layer led out from both ends of each magnetoresistive effect magnetic sensing portion (24), and (23a) and (23b) are connecting conductive layers led out from both ends of the bias conductive layer (23).

Next, the configuration of the magnetic head (3) for recording the initial tracking signal will be described with reference to FIGS. 4 and 7. In this example, this is composed of an inductive thin film magnetic head as described above. Each element is formed on the magnetic substrate (31) via a non-magnetic insulating layer such as SiO ₂ . A yoke (32) is formed on a magnetic base (3), one end of which is magnetically directly connected to the magnetic base (31), and a gap is formed between the other end of the comb-teeth shape and one end of the magnetic base (31). g is formed, and a conductive layer (33) is arranged between the yoke (32) and the magnetic base (31). Then, the tracking signal can be recorded by passing a recording tracking signal (digital signal) current through the conductive layer (33). In FIG. 4, (33a) and (33b) are connection conductive layers led out from both ends of the conductive layer (33).

In the above-described conventional magnetic head device, as described with reference to FIGS. 2 and 3, two identical magnetic heads are provided line-symmetrically on the end face of the slider so as to face the surface of the rotating magnetic recording medium. One of the magnetic heads is selected and used depending on whether it is for the purpose or for facing the back surface.

For this reason, such a magnetic head device is provided only on one side of the end surface of the slider, depending on whether the magnetic head device faces the front surface or the back surface of the rotating magnetic recording medium. The yield can be improved as compared with a magnetic head device in which a magnetic head is provided.

That is, as described with reference to FIGS. 2 and 3, is it intended to provide two identical magnetic heads line-symmetrically on the end surface of the slider so as to face the surface of the rotating magnetic recording medium. depending on whether it is intended to face the rear surface, the yield of P ₂ of the magnetic head device designed to select and use one of the magnetic head, intended to be facing the surface of the rotating magnetic recording medium Depending on whether the magnetic head device is to be opposed to the back surface, the yield of the magnetic head device in which the magnetic head is provided only on one side of the end surface of the slider is P ₁ , and the yield P _{2 is} It _{is, P 2 = 1- (1-} P 1) 2 = 2P 1 -P 1 2 next, as is apparent from FIG. 8, than yields P ₁ delta
Improve by P.

D Problem to be Solved by the Invention However, in the above-described conventional magnetic head device, although the yield is improved, two identical magnetic heads (head elements) are provided. However, the number of bonding pads is doubled, and the area of each bonding pad is reduced.

The above points are more serious as the number of magnetic heads and the number of connecting conductors led out from the magnetic heads increase.

In view of this point, the present invention proposes a magnetic head device that can reduce the number of bonding pads by half and increase the area thereof even if two identical magnetic heads are provided.

E Means for Solving Problems The first and second same head elements HE ₁ and HE ₂ formed on the common head substrate M and the common bonding pad BP _a formed on the common head substrate M , BP _b, and the first and second head elements HE ₁ and HE formed on the common head substrate M.
₂ and the common bonding pads BP _a and BP _b, and first and second connection conductors L _a1 , L _b1 ; L _a2 , L _b2, and the first and second head elements HE. ₁ and HE ₂ , so that only one effective head element is connected to the common bonding pad BP _a , BP _b , the first and second connection conductors L _a1 , L _b1 ; L
_{One of a2} and L _b2 is cut off.

According to the present invention, the first and second head elements HE ₁ ,
HE ₂ and one of the first and second connection conductors L _a1 , L _b1 ; L _a2 , L _b2 connected between the common bonding pads BP _a , BP _b are cut off to form the first and second heads. among elements HE _1, HE _2, only one valid head element is connected in common bonding pad BP _a, the BP _b.

G Example An example of the present invention will be described below with reference to FIG. 1 together with its manufacturing method. Note that, in FIG. 1, a case where two identical magnetic heads (head elements) are provided is shown for the sake of simplicity of description, but actually, the same magnetic heads (illustrated in FIGS. 2 and 3) are shown. The present invention is applied to a magnetic head device.

In FIG. ₁ , HE ₁ and HE ₂ are first and second magnetic heads (head elements) having the same function, characteristics, etc., for example, two short connecting conductive layers W _a1 , W _b1 ; W _a2 , W _b2 has been derived.

As shown in FIG. 1A, on the head substrate M, the first and second
Magnetic heads HE ₁ and HE _{2 and} common bonding pad P
Form _a and P _b . At this time, the first and second magnetic heads
Inspection pads P _a1 , P _b1 ; P _a2 , P _b2 are formed at the free ends of the connection conductive layers W _a1 , W _b1 ; W _a2 , W _b2 derived from HE ₁ and HE ₂ , respectively.

Then, the probe of the measuring device is brought into contact with the inspection pad to measure the effectiveness of the first and second magnetic heads HE ₁ and HE ₂ , and the effectiveness is stored artificially or by a computer.

Then, as shown in FIG. 1B, the inspection pads P _a1 , P _a2
And P _b1 and P _b2 are formed by subjecting the conductive layer to photolithography, respectively, to form a connection conductive layer (connection conductor) L _a1 ,
Bonding pads BP _a , BP _b via L _a2 and L _b1 , L _b2
Connect to each.

Then, according to the measurement in FIG. 1A, for example, the first magnetic head HE ₁ is invalid (disconnection, short circuit, characteristic failure, etc.),
If it is determined that the second magnetic head HE ₂ is effective, as shown in FIG. 1C, a connection conductive layer connecting the first magnetic head HE ₁ and the bonding pads BP _a and BP _b.
Part of L _a1 and L _b1 is cut by, for example, a laser.

If both the first and second magnetic heads HE ₁ and HE ₂ are effective, one of the connection conductive layers is cut off. If both the first and second magnetic heads HE ₁ and HE ₂ are invalid, this magnetic head device is considered as a defective product and discarded.

Further, as will be described with reference to FIGS. 2 and 3, in FIG. 2, for example, all of the magnetic heads (1 ₂ ), (2 ₂ ), and (3 ₂ ) are effective and If even one of the heads (1 ₁ ), (2 ₁ ), (3 ₁ ) is invalid, the connecting conductive layer L of the magnetic heads (1 ₁ ), (2 ₁ ), (3 ₁ ). Cut all ₁ 's.

Magnetic heads (1 ₁ ), (2 ₁ ), (3 ₁ ) and (1 ₂ ),
When all of (2 ₂ ) and (3 ₂ ) are valid, the connection conductive layer L _{1 of} the magnetic heads (1 ₁ ), (2 ₁ ), and (3 ₁ ) or the magnetic heads (1 ₂ ), (2 ₂ ) or (3 ₂ ) of the connection conductive layer L ₂ is cut off, but this selection is performed by the other magnetic head devices, that is, the magnetic heads (1 ₁ ), (2 ₁ ), (3 ₁ ) and the magnetic heads, respectively. Head (1 ₂ ),
Considering the number of cut connection conductive layers of (2 ₂ ) and (3 ₂ ), the two are made equal.

In the manufacturing method described with reference to FIG. 1, in the individual magnetic head device, a large number of sets of magnetic heads are simultaneously formed on, for example, an alumina wafer, and the magnetic heads are divided into magnetic heads of each set and then the second magnetic head is formed. It is obtained by mechanically processing it into the shape shown.

H Effect of the Invention According to the magnetic head device of the present invention described above, the first and second same head elements formed on a common head substrate,
A common bonding pad formed on a common head substrate and a first bonding pad formed on the common head substrate.
Of the first head element and the common bonding pad, and only one effective head element of the first and second head elements is the common bonding pad. Since one of the first and second connection conductors is cut so as to be connected to, it is possible to reduce the number of bonding pads by half and increase the area thereof.

[Brief description of drawings]

FIG. 1 is a process diagram showing a manufacturing method of an embodiment of the present invention, FIG. 2 is a perspective view showing a conventional magnetic head device, and FIG. 3 is a layout diagram of a conventional magnetic head device and a rotating magnetic recording medium. FIG. 4 is a plan view showing a conventional magnetic head device, FIGS. 5, 6, and 7 are sectional views showing specific examples of the magnetic heads of FIG. 4, respectively, and FIG. 8 is a curve showing a yield. It is a figure. M is a head substrate, HE ₁ is a first head element, HE ₂ is a second head element, BP _a and BP _b are bonding pads, L _a1 and L a, respectively.
_b1 , L _a2 , L _b2 are the connection conductive layers (connection conductors), P _a1 , P _b1 , P
_a2 and _Pb2 are inspection pads, respectively.

Claims (1)

[Claims] 1. A first and second same head element formed on a common head substrate, a common bonding pad formed on the common head substrate, and a common bonding pad formed on the common head substrate. , The first and second
Of the first head element and the second bonding conductor for connecting the common bonding pad to the common bonding pad, and only one effective head element of the first and second head elements is common to the common head. One of the first and second connection conductors is cut so as to be connected to the bonding pad of the magnetic head device.