JPS6248292B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polishing apparatus for thin film magnetic heads.
More specifically, the present invention relates to an improvement in a polishing detection resistor used in a polishing device.

In thin film magnetic heads such as magnetoresistive heads, thin film inductive heads, hole heads, etc., polishing devices are required to have high precision and efficiency as they become multi-track.

Figure 1 is a schematic diagram of a conventional magnetic head polishing device.
FIG. 2 is a diagram showing the polishing detection resistor used in the apparatus of FIG. 1 and the change in resistance as polishing progresses. In FIG. 1, 1 is a substrate such as glass, 1a
is the polished surface, 2, 2a, 2b, 2c are the polished surfaces 1
magnetic head elements arranged in a row parallel to a;
3, 3a to 3e and 4, 4a to 4e are polished surfaces 1a
several abrasive detection resistors of the same width arranged in parallel at successive distances from and having a resistance value R, 5,5
a, 5b and 6, 6a, 6b are extraction electrodes connected in parallel with the resistors 3 and 4 and led to the resistance measuring devices 7 and 8, respectively.

As shown in FIG. 2, the resistance changes of the above-mentioned resistors 3 and 4 show a stepwise rapid change with respect to the amount of polishing. Therefore, there is an advantage that the polishing position can be detected with high accuracy. These resistors 3 and 4 are provided at both ends of the element array 2 as shown in FIG. 2, and the resistance change is monitored by resistance measuring devices 7 and 8. Polished surface 1a is element row 2
If the polishing position is tilted to the left and right, the polishing positions where the resistance measurement values of the left and right measuring devices 7 and 8 change are different. Since this inclination angle (parallelism) can be easily calculated from the difference in the position where the resistance value changes, the polishing angle is adjusted by this amount to further proceed with polishing. When the resistance measurements of the left and right measuring instruments 7 and 8 start to change simultaneously, the polishing angle adjustment is completed. The final stopping point of polishing is when the resistance values of resistors 3 and 4 become infinite (open). According to the above method, since the inclination of the polishing surface can be detected and adjusted with high precision, polishing with good parallelism can be easily performed. However, as shown in FIG. 2, this method has the disadvantage that the resistance change at the beginning of polishing is small, so the accuracy is not good at the beginning of polishing.

Another conventional example is shown in FIG. In this example, in order to eliminate the above-mentioned drawbacks, the abrasive detection resistors 9a to 9e are
From the one closest to the polishing direction, R/8, R/
The resistance value is increased by sequentially changing the film thickness to 4, R/2, R, and R. If you do this,
As shown in the figure, the resistance change at the beginning of polishing becomes large;
Measurement accuracy is improved. However, there is a drawback that changing the film thickness requires a lot of effort in manufacturing.

Another conventional example is shown in FIG. This is to change the resistance value by changing the width of the polishing detection resistors 10a to 10e. Although it is easy to manufacture a resistor for detecting abrasion, it has the disadvantage that the change in resistance value becomes gradual as shown in the figure, which does not improve accuracy.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to provide a polishing device equipped with a polishing detection resistor that exhibits a large change in resistance value even at the beginning of polishing and is easy to manufacture.

In the polishing detection resistor according to the present invention, each resistive element has the same film thickness, and a thin incision is made in the element from the side opposite to the polished surface at right angles to the polished surface, and the resistance value of each element is made on the side closer to the polished surface. It is formed by forming a thin resistance portion corresponding to the

An embodiment of the present invention will be specifically described using FIG. 5. Reference numerals 11 and 11a to 11e in the figure are polishing detection resistors which are a feature of the present invention, which have the same film thickness and have a resistance value proportionality that allows good polishing detection accuracy to be obtained. Cuts 12a, 12b, and 12c are made in some of the resistors 11a to 11e. This cut is made from the side far from the polished surface, and the very narrow resistance portions 13a, 13 are made near the polished surface.
b, 13c are formed.

In this embodiment, the polishing detection resistor 11 is made of Ni-Fe.
The extraction electrode 5 uses a conductive thin film such as Au or Al. The shape of the resistor 11e is
Assuming that the width is 5 μm, the length is 100 μm, and the thickness is 0.05 μm, the resistance value R is 80Ω. In addition, the shape of the resistor 11a is 130 μm wide, 100 μm long, and 0.05 μm thick.
If the notch 12a is 75 μm wide and 5 μm long, the resistance value of the thin portion 13a is 4Ω, which is 1
The resistance value of 1a is R/8=10Ω. According to this embodiment, the resistance change of the resistor 11a is caused by the thin portion 13a.
The amount of cutting, ie, the amount of polishing, occurs within 5 μm. For this reason, the resistance change becomes sharp,
The accuracy of polishing position detection is significantly improved compared to the conventional example shown in FIG. Furthermore, the resistor elements are very easy to manufacture because the film thicknesses are the same. In the embodiment shown in FIG. 5, the resistance values of the resistors 11a to 11e are R/8, R/4, R/2, R, R, (R=80
Ω), and its resistance change is R/16 relative to the amount of polishing.
→R/8→R/4→R/2→R→∞. In this embodiment, a material different from that of the polishing detection resistor 11 is used for the extraction electrode 5, but the same material may be used.

Another embodiment of the invention is shown in FIG. According to the present invention, there is an advantage that the resistance value of each resistance element can be arbitrarily changed while keeping the change in resistance with respect to the amount of polishing sharp. By setting .about.14e to 2/5R, 6/5R, 12/5R, 4R, and R in this order, the resistance value can be changed by R/5 at equal intervals. Furthermore, in order to change the resistance value by R/n for n stages of polishing detection resistors, the resistor array is changed from the polishing surface side to 2/nR, 2・3/nR, ... (n-1)(n -2)/nR,n(n-1)/nR,R
And it is sufficient.

As described above, according to the present invention, it has become possible to measure the polishing position with high precision using a polishing detection resistor having a very simple structure.

[Brief explanation of the drawing]

Figure 1 is a schematic plan view of a conventional polishing device;
3 and 4 are a plan view and a characteristic diagram of a conventional polishing detection resistor, and FIGS. 5 and 6 are a plan view and a characteristic diagram showing each embodiment of the present invention, respectively. 1... Substrate, 1a... Polished surface, 2a, 2b, 2c...
Magnetic head element array, 5a, 5b, 6a, 6b... Takeout electrode, 7, 8... Resistance measuring device, 11a-11
e, 14a~14e...Resistance for abrasion detection, 12a~
12c...notch, 13a-13c...thin resistance part.

Claims (1)

[Claims] 1 Several polishing detectors arranged parallel to each other at a distance from the polishing surface and having an appropriate resistance value ratio are placed in front of both sides of a row of magnetic head elements parallel to the polishing surface of the substrate and arranged in a row. A resistor is provided, and the polishing detection resistors on both sides are taken out and connected in parallel with electrodes, and each is led to a resistance measuring device. During polishing, the change in resistance value of the polishing detection resistors on both sides is detected to determine the parallelism of polishing. In a polishing device for a thin-film magnetic head for adjusting the polishing surface, each element of the polishing detection resistor has the same film thickness, and a thin incision is made in each element perpendicular to the polishing surface from the opposite side to the polishing surface. A polishing device for a thin film magnetic head, characterized in that it is equipped with a polishing detection resistor formed by forming a thin resistor portion corresponding to the resistance value of each element on the near side.