JPH11296824A - Substrate for magnetoresistive head and method for testing magnetoresistive head using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate for a magnetoresistive head capable of controlling characteristics and quality of the magnetoresistive head on a substrate and a method of testing a magnetoresistive head using the same. To provide. SOLUTION: In a magnetoresistive head substrate 100 on which a plurality of magnetoresistive heads 110 each having an electrode portion 121b and an element portion 121a are formed, the magnetoresistance effect head is formed on the substrate, and the magnetoresistance effect head is formed. This is the magnetoresistive head substrate 100 on which the measuring units 120 and 121 for measuring the contact resistance Rc of the electrode and the element of the head are also formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive head substrate for manufacturing a magnetoresistive head, and more particularly to a measurement for measuring contact resistance of an electrode portion and an element portion of the magnetoresistive head. The present invention relates to a magnetoresistive head substrate having a portion and a method for testing a magnetoresistive head using the same.

[0002]

2. Description of the Related Art In recent years, hard disk drives
The areal recording density of disks has been increasing. In response to the increase in areal recording density of the hard disk, a magnetoresistive head (MR) is used as a magnetic head for signal reproduction instead of a conventional inductive head such as a thin film head.
Head). This magnetoresistive head is a head that reproduces magnetically recorded information using an element whose electric resistance changes according to a change in a magnetic field. The magnetoresistive head can obtain higher reproduction sensitivity than when reproducing a signal with an inductive head such as a thin film head. Note that an inductive head is used for writing signals.

As described above, since the magnetoresistive head utilizes electric resistance, it is extremely important to manage the resistance value of the magnetoresistive head in managing the characteristics and quality of the magnetoresistive head. Becomes The resistance value of the magnetoresistive head specifically includes the resistance value of the element portion, the resistance value of the lead material, the contact resistance value between the element portion and the electrode material, and the like. Of these, the resistance value of the element portion and the resistance value of the electrode material can be calculated theoretically from the width, length, thickness, specific resistance, etc. of the member. It can be done relatively easily.

[0004]

However, among the resistance values of this magnetoresistive head, the contact resistance value between the element portion and the electrode material cannot be determined as a basic element for calculating the contact resistance value. Therefore, the theoretical resistance value could not be calculated, and thus the contact resistance value could not be managed. In particular, in a so-called spin-valve magnetoresistive head, among the magnetoresistive heads, its element part is an electrode part,
Since the structure is such that the contact is made at the end, the contact resistance value increases. Therefore, measuring the contact resistance between the element part of the magnetoresistive effect head and the electrode material requires:
It was also very important to control the characteristics and quality of the magnetoresistive head.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a magnetoresistive head substrate capable of controlling the characteristics and quality of the magnetoresistive head on the substrate. And a method for testing a magnetoresistive head using the same.

[0006]

According to the present invention, there is provided a magnetoresistive head substrate on which a plurality of magnetoresistive heads each having an electrode portion and an element portion are formed.
The magneto-resistance effect head is formed on the substrate, and a measurement unit for measuring contact resistance of an electrode portion and an element portion of the magneto-resistance effect head is also formed. This is achieved by using a substrate.

Further, the object of the present invention is to provide a magnetoresistive head substrate on which a plurality of magnetoresistive heads each having an electrode portion and an element portion are formed. Further, a measurement section for measuring the contact resistance of the electrode section and the element section of the magnetoresistive head is formed on the same substrate, so that the resistance of the magnetoresistive head is measured. Achieved by the test method of the effect head.

According to the above structure, the magnetoresistive head is formed on the magnetoresistive head substrate on which a plurality of magnetoresistive heads are formed, and the contact resistance of the electrodes and the element of the magnetoresistive head is controlled. Is also formed, so that the contact resistances of the electrodes and elements of the magnetoresistive head actually manufactured can be grasped for each substrate.

[0009]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Although the embodiments described below are preferred specific examples of the present invention, various technically preferable limitations are given. However, the scope of the present invention is not limited to the following description. It is not limited to these forms unless otherwise stated.

FIG. 1 is a diagram showing an embodiment of a magnetoresistive head substrate and a method of testing a magnetoresistive head using the same according to the present invention. In FIG. 1, a wafer 100 as a substrate for a magnetoresistive effect head is
0, the actual magnetoresistive heads 110, 110, 1
10, a test pattern for measurement (TEST ELEMENT GROPE) 120, which is a plurality of measurement units.
120 are formed. This measurement test pattern 12
0 and 120 are specifically as shown in FIG. That is, the measurement test pattern 121 with the element portion shown in FIG.
And a magnetoresistive effect film (MR film) 12 as an element portion provided between the electrode materials 121b.
1a. And, for example, Cr / CoCr
On the electrode material 121b made of Pt / Tiw / Ta or the like, a lead 1 made of, for example, Cr / Cu or the like is provided.
21c is provided.

Here, the measurement test pattern 121 with the element portion is formed as follows. First, the wafer 10
0, a lower shield film is formed, and
A gap film made of l2 O3 or the like is formed. And
The MR film 121a is formed on the gap film. This gap film is for insulating between the MR film 121a and the lower shield. And this M
An electrode material 121b for transmitting a change in electrical resistivity in the MR film 121a is formed so as to sandwich the R film 121a, and a lead 121c for further transmitting the change in electrical resistivity to the outside is formed on the electrode material 121b. here,
The MR film 121a has, for example, a structure as shown in FIG. In FIG. 3, the MR film 121a is, for example, a spin valve laminate that is the MR film 121a of the spin valve magnetoresistive head.

In FIG. 3, a spin valve laminated body, which is an MR film 121a, has a first magnetic thin film layer (d), a non-magnetic thin film layer (c),
It has a second magnetic thin film layer (b) and an antiferromagnetic thin film layer (a). A high-resistance coating layer B is provided on the antiferromagnetic thin film layer (a). In the spin valve laminate having the above structure, the first magnetic thin film layer (d) and the second magnetic thin film layer (b), which are two magnetic layers, are nonmagnetic thin film layers. The material is magnetically separated by (c) to form a sandwich structure. Then, by laminating the antiferromagnetic thin film layer (a) on the second magnetic thin film layer (b), the exchange bias magnetic field generated at the interface is applied to the second magnetic thin film layer (b). Applied. However, this exchange bias magnetic field does not affect the first magnetic thin film layer (d) provided on the opposite side of the nonmagnetic thin film layer (c). On the other hand, the first magnetic thin film layer (d) is affected by a magnetic field given from a hard disk (not shown) or the like, but this magnetic field does not affect the second magnetic thin film layer (b). Will be.

Therefore, in the first magnetic thin film layer (d) and the second magnetic thin film layer (b), the direction of magnetization changes to parallel or anti-parallel, whereby the electrical resistivity changes greatly. Will be. Such a change in the electric resistivity of the MR film 121a is transmitted to the electric material 121b and the lead 121c, and is detected by a detection circuit (not shown), thereby reproducing information from, for example, a hard disk. On the other hand, the magnetoresistive head 110 shown in FIG. 1 formed on the same wafer 100 as the measurement test pattern 121 with the element portion has the test pattern 1 with the element portion.
Unlike FIG. 21, a recording coil, a recording magnetic pole, a protective film, and the like are further formed. Thus, the actual magnetoresistive head 110 is formed on the wafer 100.

On the wafer 100, there is provided another measurement test pattern 122 which is a measurement test pattern 120 having a different configuration from the measurement test pattern 121 with the element portion. Other test patterns for measurement 122 include:
Except for the configuration of the element section, the configuration is the same as that of the measurement test pattern 121 with the element section shown in FIG. Specifically, as shown in FIG. 2B, unlike the test pattern 121 for measurement with an element portion, the MR film 1 as an element portion
21a is not formed, and instead, an electrode material 121b having the same shape as the MR film is provided. With this configuration, the MR film 121 serving as the element portion is formed.
a and the electrode material 121b are not connected.

The dimensions of the track widths TW and TW of the measurement test pattern 121 with the element portion and the other measurement test patterns 122 shown in FIG. 2 are formed to be the same.
The measurement test pattern 121 with the element portion and the other measurement test patterns 122 having the track widths TW and TW having the same dimensions are, for example, 1 μm and 2 μm.
5 μm, 3 μm, 4 μm and 5 μm, wafer 100
Formed on top. Further, the measurement test pattern 121 with the element portion shown in FIG.
The height H of the element portion (MR film) 22 and its corresponding portion is
It is formed identically. Using the measurement test pattern 121 with the element portion and the other measurement test patterns 122 configured as described above, the magnetoresistive head 11
A method for measuring the contact resistance between the zero MR film 121a and the electrode material 121b will be described below.

First, a measurement test pattern 1 with an element portion
The resistance R1 of the measurement test pattern 121 with the element portion and the resistance R2 of the other measurement test pattern 122 are measured using the measurement test pattern 122 and the other measurement test patterns 122. Then, the resistance R of the measurement test pattern 121 with the element portion is measured.
1 and the resistance 2 of the other test pattern for measurement 122 can be expressed by the following equation. In the following formula, Rmr
Is the sheet resistance of the MR film 121b, Tw is the track width TW, R
c is a contact resistance between the MR film 121b and the electrode material 121b. Rl1 and Rl2 are connected to the lead 121c.
The resistance, Rp, is the sheet resistance of the electrode material 121b.

R1 = Rmr × Tw + Rc + R11 (1) R2 = Rp × Tw + R12 (2) The difference Rdiff between Expression (1) and Expression (2) is: It looks like this: Rdiff = R1−R2 = (Rmr−Rp) × Tw + Rc + R11−R12 (3) At this time, the resistance of the lead 121c of the measurement test pattern 121 with the element and the other measurement test pattern 122
The resistance of the lead 121c is as follows since the configuration is the same as described above. R11 ≒ R12 (4) Therefore, Rdiff = (Rmr−Rp) × Tw + Rc (5)

According to the equation (5), when the track width Tw of the measurement test pattern 121 and the track width Tw of the other measurement test pattern 122 become 0, the resistance R1 of the measurement test pattern 121 and the other resistance are changed. Test pattern for measurement 12
2 is the contact resistance Rc between the MR film 121b and the electrode material 121b. In other words, a plurality of sets of the measurement test pattern 121 with the element portion and the other measurement test patterns 122 having the same dimensions and the track width Tw formed on the wafer 100 are provided as one set having the same dimensions. . For example, five sets of 1 μm, 2 μm, 3 μm, 4 μm, and 5 μm are provided on the wafer 100. Therefore, the intercept of the correlation function of the difference between the resistances R1 and R2 of the measurement test patterns 121 and 122 for each set is the contact resistance Rc.

FIG. 4 shows the measurement test patterns 121 and the other measurement test patterns 122 with the element portions (MR films) and the heights H of the corresponding portions thereof being constant and five types of track widths Tw. Resistance R of 121 and 122
It is the figure which measured the difference of 1, R2. That is, for example,
The element portion (MR film) of the measurement test pattern 121 and the other measurement test pattern 122 and the height H of the corresponding portion are 2.0 μm, and the measurement test pattern 121 and the other measurement tests having different track widths Tw. Pattern 12
2 is formed on five types of wafers 100. The track width Tw is 1 μm, 2 μm, 3 μm, 4 μm and 5 μm
m. The above-described resistors R1. The star mark indicates the difference in R2 on the figure.

The height H of the element portion (MR film) of the measurement test pattern 121 and the other measurement test patterns 122 and the corresponding portion is set to 0.8 μm, and the track width T
w are formed on the wafer 100, and the above-described resistors R1. R
The difference between the two is indicated by a square mark on the figure. According to the above equation (5), when the track widths Tw and Tw of the measurement test pattern 121 and the other measurement test patterns 122 become 0, the resistance R of the measurement test pattern 121 becomes zero.
The difference between 1 and the resistance R2 of the other test pattern for measurement 122 becomes the contact resistance Rc between the MR film 121b and the electrode material 121b as it is. Therefore, in FIG.
When the track width Tw is 0 μm, the resistances R1. The difference in R2 is due to the MR film 121
It becomes the contact resistance Rc between b and the electrode material 121b.

Specifically, the measurement test pattern 121
And the element portion of the other test pattern 122 for measurement (MR
When the height H of the film and its corresponding portion is 0.8 μm, the contact resistance Rc is 3.00 ohm, and when the height H is 2.0 μm, the contact resistance Rc is 1.19 ohm. Become. As described above, according to the present embodiment, the measurement test pattern 121 with the element portion and another measurement test pattern 122 are provided on the wafer 100 on which the magnetoresistive head 110 is formed. The height H of the element portion (MR film) 121a or a portion corresponding to the element portion is determined.
Are formed in the same manner, and a plurality of other types of measurement test patterns 121 and 122 having different track widths Tw are provided on the wafer 100.

The measurement test patterns 12
When the resistances R1 and R2 of the reference numerals 1 and 122 are measured and the measured values are shown on the drawing, the portion where the track width Tw is 0 μm in the drawing becomes the contact resistance Rc between the MR film 121b and the electrode material 121b. Therefore, the contact resistance Rc between the MR film 121b and the electrode material 121b of the magnetoresistive head 110 actually manufactured can be grasped for each wafer 100. Therefore, the management of the magnetoresistive head 110 including the contact resistance Rc in the state of the wafer 100 can be performed, and the quality control can be improved. In addition, since the abnormality of the contact resistance Rc can be confirmed in the state of the wafer 100, the feedback for the abnormality can be quickly performed. Further, a failure analysis when a resistance failure of the magnetoresistive head 110 occurs can be easily performed, and it can also be used as an evaluation method such as a study for reducing the contact resistance Rc. Since the target resistance at the time of the depth processing can be accurately calculated, the processing accuracy can be improved.

[0023]

As described above, according to the present invention, a magnetoresistive head substrate and a magnetoresistive head substrate capable of controlling the characteristics and quality of the magnetoresistive head on the substrate. It is possible to provide a method for testing the magnetoresistive head used.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a magnetoresistive head substrate and a method of testing a magnetoresistive head using the same according to the present invention.

FIG. 2 is a diagram showing a measurement test pattern as a plurality of measurement units in FIG.

FIG. 3 is a diagram showing a structure of an MR film in FIG. 2;

FIG. 4 is a diagram illustrating a difference between resistances of a test pattern for measurement and another test pattern for measurement.

[Explanation of symbols]

100: wafer, 110: magnetoresistive head, 120: test pattern for measurement, 121:
Measurement test pattern with element, 121a... MR
Membrane, 121b ... electrode material, 121c ... lead,
121: Other test pattern for measurement, A: Underlayer, Tw: Track width, H: Element part (MR film)
And the height of its substantial part.

Claims (3)

[Claims] 1. A magnetoresistive head substrate on which a plurality of magnetoresistive heads each having an electrode portion and an element portion are formed, wherein the magnetoresistive head is formed on the substrate and the electrodes of the magnetoresistive head are formed. A substrate for a magnetoresistive head, further comprising a measuring unit for measuring contact resistance of the unit and the element unit. 2. A test pattern for measurement in which the measuring section includes the element section and the electrode section of the magnetoresistive head, and the element section of the magnetoresistive head is formed of the same material as the electrode section. 2. The magnetoresistive head substrate according to claim 1, wherein the substrate comprises a test pattern for measurement. 3. A substrate for a magnetoresistive head having a plurality of magnetoresistive heads each having an electrode portion and an element portion, wherein said magnetoresistive head is formed on said substrate, and said magnetoresistive head is formed on the same substrate. A magnetoresistive head testing method for measuring a resistance value of the magnetoresistive head by forming a measuring section for measuring contact resistance of an electrode section and an element section of the magnetoresistive head.