JPH01184613A - Resistance monitor pattern for thin film magnetic head - Google Patents

Abstract

PURPOSE:To extremely improve a gap working yield by using a monitor pattern in which L/W is above 66.7 in a target gap depth when the length of a monitor pattern is defined to be L and the width is defined to be W. CONSTITUTION:A resistance monitor pattern 13 is disposed on the same line as the gap 11a of a thin film magnetic head 11 on a wafer 12. The length of the patter 13 is defined to be L=500mum, and the width is to be W. At the time of processing the gap, the accuracy of the target gap depth is + or -0.5mum and the outstanding variation of a resistance value to the change of the width of a resistance monitor capable of correctly detecting the change of this 0.5mum is above 200OMEGA/mum, and in this case the width W is below 7.5mum. Accordingly, the value of L/W=500/7.5 is 66/6... and when the monitor pattern of more than 66.7 is used, the gap depth can be finished with high accuracy to improve a processing yield.

Description

[Detailed Description of the Invention] [Summary] When forming an RrlA'in air head on a wafer,
A resistance monitor pattern is provided on the same line as the gap of the 111Q magnetic head, is processed together with the recording medium facing surface of the gap, and has a resistance value that changes depending on the gap depth of the thin film magnetic head. , with the purpose of providing an effective shape of a resistance monitor pattern that improves the yield during gap processing, and when the length of the monitor pattern is 11 and the width of the monitor pattern is W, the target gap depth is When, L/W
is 66.7 or more.

[Industrial Application Field] The present invention provides, when forming a thin film magnetic head on a wafer, a thin film magnetic head that is provided on the same line as the gap of the thin film magnetic head, and that is processed together with the surface of the gap facing the recording medium, Depending on the gap depth of the thin film magnetic head,
This invention relates to a resistance monitor pattern in which the resistance value changes.

The 11g1 magnetic head has been developed to solve the problem of workability of ferrite magnetic heads and to satisfy the demand for higher BS of magnetic materials. This thin film magnetic head requires gap processing of a wafer on the surface of which a coil material is formed by sputtering or plating with an accuracy of about 1 μm, and a processing method with high yield is desired.

[Prior Art] FIG. 6 is a plan view showing an example of an II film magnetic head, FIG. 7 is a sectional view taken along line AA in FIG. 6, FIG. 8 is an explanatory diagram of the manufacturing process of a thin film magnetic head, and FIG. The figure is a diagram explaining gap machining.

First, the structure of the thin film magnetic head will be explained using FIGS. 6 and 7. In the figure, 1 is a wafer serving as a substrate, 2
is the lower core of permalloy formed on wafer 1, 3
4 is a gap material formed on the lower core 2, 4 is an insulating film formed on the gap material 3, 5 is a copper coil patterned in a spiral shape on the insulating film 4, and 6 is an insulation covering the coil 5. Membrane 7 is a permalloy upper core formed on insulation IIIG. 8 is a magnetic recording medium, and this magnetic recording medium 8 moves in the direction of the arrow in FIG.

Then, recording/reproduction is performed by the magnetic field generated in the gap G.

Next, the manufacturing process of the iWIIIim head will be explained using FIG.

First, prepare a wafer 1 with a predetermined shape (step 1)
.

Next, the above-mentioned lower core 2 and gap material 3 are placed on the wafer 1.
, an insulation lI4, a coil 5, an insulating film 6, and an upper core 7.
0 pieces) are formed (Step 2).

Next, it is divided into rows by machining, and gap processing is performed (step 3).

Next, the wafer 1 in columns is divided into individual 11111-wafer heads H (step 4).

Then, the divided thin film magnetic head H is further processed into a predetermined shape and attached to, for example, the arm 9 of a fixed magnetic disk device (step 5).

Here, the gap machining in step 3 will be explained using FIG. 9. In this gap machining, the surface 1a of the wafer 1 facing the recording medium is ground in the direction of the arrow until it reaches the target gap depth D (see FIG. 7). Since the dimensional accuracy of this gap depth D is ±0.5 μmFj degrees, the following means are used to grasp the processing status.

In step 2, on both ends of each row of thin film magnetic heads H formed on the wafer 1, a resistance monitor pattern 10 accurately aligned with the gap G of the thin film magnetic head H is placed on the thin film magnetic head. Form it together with H. Then, in step 3, as the recording medium facing surface 1a is ground, the resistance monitor pattern 10 is also ground.

As the grinding process progresses, the electrical resistance value of the resistance monitor pattern 10 increases to grasp the machining situation.
The target gear V-tube depth D is obtained. Incidentally, such means is called a resistance monitoring method.

[Problems to be Solved by the Invention] However, in the resistance monitoring method in the conventional example with the above configuration, there are no particular regulations regarding the shape and arrangement of the resistance monitoring pattern 10, and the process is carried out by trial and error. There is a problem that the yield is poor.

The present invention has been made in view of the above problems, and an object thereof is to provide an effective shape of a resistance monitor pattern that improves the yield during gap processing.

[Means for solving the problems] FIG. 1 is a diagram showing the principle of the present invention. In the figure, 11 is a thin film magnetic head formed on a wafer 12, and 13 is provided on the same line as the gap 11a of the thin film magnetic head 11 on the wafer 12.

This is a resistance monitor pattern with a length of 9 and a width of W. Also, 12a
is the recording medium facing surface of the gap 11a.

[Function] In FIG. 1, the recording medium facing surface 12 of the gap 11a
When processing a, the resistance monitor pattern 12 is also processed. When the recording medium facing surface 12a reaches the target gap depth (indicated by a two-dot chain line in the figure), L/W in the resistance monitor pattern 13 becomes 66.7 or more.

[Example] Next, an example of the present invention will be described using the drawings. Second
3 is an enlarged configuration diagram of the resistance monitor pattern in FIG. 2, and FIG. 4 is a diagram showing the resistance characteristics of the resistance monitor pattern in FIG. 2.
FIG. 5 is a diagram showing resistance value change amount characteristics with respect to width changes of the resistance monitor pattern in FIG. 2.

In FIG. 2, this figure shows the wafer divided into columns in step 3 of FIG. 8, which has already been explained. A plurality of thin film magnetic heads 22 (seven in this embodiment) are formed on this wafer 21. Thin Pa1a
At both ends of the row of air heads 22, resistance monitor patterns 23 made of titanium are formed.

Next, the resistance monitor pattern 23 will be explained using FIG. The resistance monitor pattern 23 is provided on the same line as the gap 22a and has a length.

A resistance monitor pattern main body portion 23a having a width of W, a bridge portion 23b bent at both ends of the resistance monitor pattern main body portion 23a, and extending in a direction opposite to the gap 22a. Connection part 23
b and a terminal portion 23c provided at the tip.

A tester (not shown) is connected to this terminal portion 23C so that the vl-resistance value of the resistance monitor pattern main body portion 23a can be monitored. The two-dot chain line indicates the line of the magnetic recording medium facing surface 21a when the target gap depth D (see FIG. 7) is reached. When the resistance monitor pattern main body 23a is ground to the target gap length D, the ratio of the length to the width W (L/W near aspect ratio) is configured to be 0.67. There is.

Next, the operation of the above configuration will be explained. In the magnetic recording medium facing surface 21a of the wafer 21 divided into columns, the aspect ratio of the resistance monitor pattern main body 23a is 0.6.
It is ground until it becomes 7.

Here, the reason for such a ratio will be explained.

The resistance 1i1R of the resistance monitor pattern main body portion 23a is expressed by the following formula.

R= (LXρ)/(WXt)...■Here, ρ; electrical conductivity t; film thickness In this example, L=500 μm, W-150 μm
As the magnetic recording medium facing surface 21a is ground, the resistance value R of the resistance monitor pattern main body portion 23a becomes a characteristic as shown in FIG.

Further, the amount of change in resistance value with respect to the change in width of the resistance monitor pattern main body portion 23a is as follows from equation 0.

dR/dW-k (L/W2) ・
...■Here, k: proportionality constant The amount of change in resistance value with respect to change in width in this embodiment has a characteristic as shown in FIG.

The accuracy of the target gap depth is 10.5 μm, so the fifth
In the figure, the range in which a change of 0.5 μm can be accurately detected, that is, the area where the amount of resistance change with respect to the width change is significant, is 200Ω/It m or more, and in this case, the width W of the resistance monitor pattern main body 23a is , 7.5 μm or less.

The length of the resistance monitor pattern main body 23a is 5.
00 μm, L/W-500/7.5 -66.666... Therefore, when the target gap depth is reached, the aspect ratio (L/W) of the resistance monitor pattern main body 23a becomes 66.
．． If you use a resistance monitor pattern that is 7 or more,
The gap depth can be finished with high precision. By using such a shape of the resistance monitor pattern 23, the yield during gap processing can be improved.

Note that the present invention is not limited to the above embodiments.

In the above embodiment, the resistance monitor patterns 23 are provided at both ends of the seven thin film magnetic heads 22 arranged in a row, but the present invention is not limited thereto. For example, a resistance monitor pattern 23 may be provided for each thin-film magnetic head 22.

[Effects of the Invention] As described above, according to the present invention, it is possible to realize an effective shape of a resistance monitor pattern that improves the yield during gap processing. −

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, FIG. 3 is an enlarged block diagram of the resistance monitor pattern in FIG. 2, and FIG. FIG. 5 is a diagram showing the resistance value change characteristics with respect to the width change of the resistance monitor pattern in FIG. 2; FIG. 6 is a plan view showing an example of the US magnetic head; Figure 7 is A- in Figure 6.
A sectional view, FIG. 8 is an explanatory diagram of the manufacturing process of the ii*ta air head, and FIG. 9 is a diagram illustrating gap processing. 1 to 5, 11.22 is a thin film magnetic head, 11a and 22a are gaps, 12.21 is a wafer, 12a and 21a are recording medium facing surfaces, and 13.23 is a resistance monitor pattern. ■ Resistance monitor pattern shown in Fig. 2 0 l angle showing resistance characteristics ■ 4 Fig. 5 Fig. Angle etc. 6 Fig. 72

Claims (1)

[Claims] When forming a thin film magnetic head (11) on a wafer (12), the gap (11) of the thin film magnetic head (11) is
a), and the gap (11a
), the resistance monitor pattern (13) is machined together with the recording medium facing surface (12a) and has a resistance value that changes depending on the gap depth of the thin film magnetic head (11). A thin film magnetic head characterized in that when the length of the monitor pattern (13) is L and the width of the monitor pattern (13) is W, L/W is 66.7 or more when the target gap depth is reached. resistance monitor pattern.