JPH044101B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a polishing device for a thin film magnetic head such as an electromagnetic induction magnetic head or a magnetoresistive magnetic head, and in particular to a polishing amount monitor for detecting the amount of polishing. It is about improvement.

[Prior art]

In general, thin film magnetic heads such as electromagnetic induction magnetic heads and magnetoresistive magnetic heads are manufactured by bonding a second reinforcing substrate onto a first substrate on which a thin film pattern of the thin film magnetic head body is formed. By polishing the portion of the substrate that will become the sliding surface of the recording medium, it will be ready for practical operation. This polishing process improves the contact with the recording medium, such as a magnetic tape such as a video tape, by making the sliding surface of the recording medium a smooth curved surface.At the same time, by controlling the amount of polishing, the depth of the electromagnetic induction magnetic head can be improved. This is done for the purpose of controlling the length or stripe width in a magnetoresistive magnetic head.

By the way, normally in the manufacturing process of thin-film magnetic heads, the total amount of polishing due to the above-mentioned polishing process is several tens to several hundred μm, but at the end of the polishing,
The depth length or stripe width is ±1 to several μ
Therefore, in the polishing process, a so-called polishing amount monitor, which is a means for easily detecting the amount of polishing with high precision, is required.

That is, the polishing amount monitor is formed on a first substrate on which a thin film magnetic head body is formed as a thin film pattern whose relative position with respect to the magnetic head body is determined in advance, and the monitor pattern is formed as the polishing process progresses. The amount of polishing is controlled by optically or electrically detecting changes in the state of the polishing.

In conventional polishing apparatuses, for example, optical polishing amount monitors shown in FIGS. 1 and 2 have been devised, and in the case of FIG. A triangular thin film pattern 2 whose cross section gradually increases as the polishing of the substrate 1 progresses is formed on the substrate 1, and the cross section of the pattern 2 is observed from the polished surface P using a microscope or the like, and the cross-sectional length of the pattern 2 is determined. The amount of polishing is detected by measuring l, and in the case of FIG. formed in a direction perpendicular to
The amount of polishing is detected by measuring the number of patterns 3 visible from the polishing surface P.

In addition, as electrical polishing amount monitors, those shown in Figures 3 and 4 have been devised.
In the case of the figure, a thin film resistor 4 whose resistance value changes by being removed by polishing and a terminal 5 for extracting the change in resistance value of the resistor 4 are formed on the substrate 1.Furthermore, in the case of FIG. A terminal 7 connects each resistor 6 in parallel to a plurality of band-shaped thin film resistors 6 which are parallel to the polishing surface P and arranged at positions with increasing distances from the polishing surface P on the top, and extracts resistance value changes. are formed, and the amount of polishing is detected by measuring the change in resistance value of each. Note that FIGS. 3b and 4b show the relationship between the resistance value and the polishing amount, respectively.

By the way, when using this type of polishing device to mechanize polishing, it is desirable to detect the amount of polishing while the polishing is progressing or at least with the substrate attached to the polisher. Are suitable.

However, according to the above-mentioned electrical polishing amount monitor, in the case of Figure 3, the measured value, that is, the resistance value of the resistor 4, is a continuous variable and no noticeable change can be obtained, so it is difficult to correlate it with the polishing amount. There are drawbacks.
The same can be said of the structure of the optical polishing amount monitor shown in FIG. 1. Also, the fourth
In the case of the figure, since the measured values are discontinuous variables and noticeable changes are obtained, it is easy to correlate them with the amount of polishing. Therefore, the accuracy of detecting the amount of polishing is limited by the pitch at which the resistors 6 are arranged, and there is a drawback that the accuracy of detecting the amount of polishing is restricted.

Furthermore, the configurations shown in FIGS. 3 and 4 have the disadvantage that the resistance value change at the initial stage of polishing is very small, as is clear from the respective diagrams b, so that the polishing accuracy at the early stage of polishing is very poor.

By the way, conventionally, as shown in FIGS. 5 and 6, a thin film resistor 4' whose cross section gradually increases as polishing progresses, and a plurality of thin film resistors whose length gradually increases in the polishing progress direction have been used. A body 6' is provided,
As shown in each figure b, a method has been devised in which the relationship between the amount of polishing and the resistance value is made linear as a whole, that is, close to a proportional linear type, and the change in the resistance value at the initial stage of polishing is increased. However, the fifth
In the case of the figure, since the measured value is a continuous variable, it is difficult to correlate it with the amount of polishing, and in the case of FIG. 6, the accuracy of detecting the amount of polishing is limited by the arrangement pitch of the resistor 6', which The shortcomings still remain unresolved.

[Purpose of the invention]

This invention has been made with the above points in mind, and aims to improve an electrical polishing amount monitor suitable for mechanization and automation of polishing processes, and to perform polishing amount detection work more easily and with high precision. shall be.

[Structure of the invention]

This invention provides a plurality of wires arranged on a substrate on which a thin film magnetic head main body is formed, at positions with increasing distances from the polished surface of the substrate, and which are removed by polishing the substrate, causing a resistance value to change and eventually to break. a plurality of second thin film resistors which are paired with each of the first thin film resistors and whose resistance value does not change due to disconnection of the first thin film resistors of each pair; , the first and second thin film resistors in each pair are connected in series, each of the first thin film resistors being short-circuited and having electrodes on both sides long in the polishing progress direction and a comb tip passing between each of the first thin film resistors; A polishing apparatus for a thin film magnetic head is characterized in that a comb-shaped thin film conductor is formed to connect the second thin film resistors in parallel.

〔Effect of the invention〕

Therefore, according to the thin film magnetic head polishing apparatus of the present invention, a resistance circuit is configured by each first thin film resistor on the substrate, each second thin film resistor, and a comb-shaped thin film conductor, and each first thin film resistor is Since each second thin film resistor paired with the body is disconnected from the circuit in sequence due to the wire breakage caused by polishing the body, a large discontinuous change in resistance value due to polishing can be obtained between both electrodes of the thin film conductor. Therefore, the resistance value and the amount of polishing can be easily correlated, and since each first thin film resistor can be sequentially arranged diagonally with respect to the polishing progress direction, the first thin film resistor in the polishing progress direction can be The arrangement pitch of the resistors can be set arbitrarily, and highly accurate resistance value detection, that is, polishing amount detection can be performed.The polishing process can be mechanized and automated, and highly accurate polishing amount control can be realized.

Furthermore, in the electrical polishing amount monitor,
By arranging only the first thin film resistors with high precision relative to the main body of the thin film magnetic head on the substrate, the amount of polishing can be detected with high precision, and each second thin film resistor has freedom in its shape and arrangement. The resistance can be increased, and the change in resistance value of the resistor circuit can be set arbitrarily.

Further, when the thin film magnetic head body formed on the substrate is a magnetoresistive element layer of a magnetoresistive magnetic head, a first thin film resistor is formed and patterned simultaneously with the element layer. Therefore, there is an effect that the relative positions of the two can be regulated with high precision.

〔Example〕

Next, this invention will be explained in detail with reference to the drawings from FIG. 7 showing an embodiment thereof.

First, FIG. 7 and FIG. 8 showing one embodiment will be explained.

FIG. 7 shows one side of the electrical polishing amount monitors formed on both sides of a row of thin film magnetic head bodies arranged in a row parallel to the polishing surface of the substrate;
In the figure, 8a, 8b, 8c, 8d, and 8e are arranged at positions with increasing distances from the polishing surface P of the substrate, and are arranged at intervals in an oblique direction tilted to the left with respect to the polishing progress direction. Five first thin film resistors are arranged, and each of the resistors 8a to 8e is arranged at a constant pitch in the polishing progress direction by determining the relative position with respect to the main body of the thin film magnetic head on the substrate in advance.
Each of the resistors 8a to 8e is removed one after another as the substrate is polished, so that its resistance value changes and eventually becomes disconnected. 9a, 9b, 9c, 9d, and 9e are five second thin film resistors that are paired with each of the first thin film resistors 8a to 8e, and each of the second thin film resistors 9a to 9e is paired with at least one of the first thin film resistors 8a to 8e. The resistance value does not change due to disconnection of each pair of first thin film resistors 8a to 8e.

And, when the resistance values of each of the second thin film low antibodies 9a to 9e are respectively Ra, Rb, Rc, Rd, and Re,
There is a relationship of Ra<Rb<Rc<RdRe, and the resistance value of each of the first thin film resistors 8a to 8e is much smaller than that of the second thin film resistors 9a to 9e.

10 is a comb-shaped thin film conductor, and a shorting conductor part 1 short-circuits each of the first thin film resistors 8a to 8e on the polishing surface P side.
1, electrodes 12A and 12B for taking out the resistance value, which are integrally provided on both sides of the short-circuit conductor part 11 and are each formed long in the polishing progress direction, and the short-circuit conductor part 11
Comb lead body portions 13a, 13b, 13c are formed integrally with the first thin film resistors 8a to 8e and extend in the polishing progress direction from the right side of each of the first thin film resistors 8a to 8e, and short-circuit between the adjacent first thin film resistors 8a to 8e. ,13
d, 13e, each comb guide body part 13
The second thin film resistors 9a to 9e are connected between the tips of each of the electrodes a to 13e and the electrode 12B, so that the first thin film resistors 8a to 9e of each pair
8e and second thin film resistors 9a to 9e are connected in series, respectively, and each second thin film resistor 9a to
9e are connected in parallel. In addition, 14 indicates the position of the polishing disconnection at the connecting part between the short-circuit conductor part 11 and the electrode 12B, and the position 14 is on the side of the polishing surface P from the disconnection position of the first thin film resistor 8a that is closest to the polishing surface P. They are formed at positions shifted by the arrangement pitch of each of the first thin film resistors 8a to 8e.

Then, when polishing is started, in the initial polishing at the short-circuit part 11 of the thin film conductor 10, both electrodes 12A and 12B are short-circuited at the short-circuit part 11, so the resistance value becomes zero as shown in FIG. , when the polishing reaches the first thin film resistor 8a, both electrodes 12
A and 12B are connected through the resistor 8a, but since this resistance value is very small, there is almost no change in the resistance value.

Next, when the polishing reaches the polishing disconnection position 14 and disconnects it, the second thin film resistor 9a is connected between the two electrodes 12A, 12B via the first thin film resistors 8a, 8b and the comb lead body part 13a. As a result, the resistance value increases as shown by x in FIG. As the polishing progresses, the first thin film resistor 8
a and 8b are gradually removed, the resistance value increases slightly, and when the first thin film resistor 8a is disconnected, the second thin film resistor 9a that is paired with it increases.
is disconnected from the resistance circuit, so the first
The second thin film resistor 9b connects to both electrodes 12A, 12 via the thin film resistors 8b, 8c and the comb lead body portion 13b.
B, and the resistance value increases as shown by a in FIG.

Similarly, the first thin film resistors 8b, 8c, 8
Each time d and 8e are disconnected, b and 8e are shown in Fig. 8, respectively.
Resistance values are obtained as shown in c, d, and e, and discontinuous and relatively large changes in resistance value are obtained.

Therefore, according to the embodiment, when each of the first thin film resistors 8a to 8e, whose relative position with respect to the thin film magnetic head on the substrate is determined in advance, is disconnected, each of the second thin film resistors forming a pair therewith is disconnected. Body 9a-9e
can be sequentially separated from the circuit, it is possible to obtain a discontinuous and relatively large change in resistance value with respect to the amount of polishing, and it is extremely easy to correlate the amount of polishing with the resistance value. Body 8a~
Since the resistors 8e are arranged diagonally to the direction of polishing progress, the arrangement pitch of the first thin film resistors 8a to 8e with respect to the direction of polishing progress can be set arbitrarily, realizing highly accurate detection of the amount of polishing. It is possible.

In addition, each of the second thin film resistors 9a to 9e is not subject to any particular restrictions on the arrangement or shape with respect to the main body of the thin film magnetic head, and has a large degree of freedom, so that discontinuous changes in the resistance value of the resistance circuit can be set arbitrarily. It has the advantage that the first and second thin film resistors 8a to 8e,
Since the comb-shaped conductor parts 13a to 13e are arranged in steps on the thin film conductor 10 that connects 9a to 9e, the amount of polishing is detected by observing the cross section of the comb-shaped conductor parts 13a to 13e on the polishing surface P. It can also be used as an optical polishing amount monitor.

In the above embodiment, when the thin film magnetic head is a magnetoresistive magnetic head, the first and second layers are simultaneously formed in the magnetoresistive element layer of the magnetic head.
By forming the thin film resistors 8a to 8e, 9a to 9e and simultaneously forming the comb-shaped thin film conductor 10 at the same time as the conductor layer for conducting current of the magnetic head, the first thin film resistor which regulates the timing of resistance value change of the resistance circuit can be formed. The arrangement of 8a to 8e and the arrangement of the magnetoresistive element layer can be precisely matched within the pattern precision of one etching mask, and the stripe width by polishing can be controlled with high precision.

Next, the drawings from FIG. 9 onwards showing other embodiments will be explained.

In these drawings, the same symbols as above indicate the same or corresponding parts. A recess is formed so that the wires 8e to 8e are disconnected before they disappear by polishing, and the pattern shape of each second thin film resistor 9a to 9e is changed to change the resistance value of each second thin film resistor 9a to 9e.
As shown in FIG. 10, the resistance value as a whole changes linearly with respect to the amount of polishing.

Therefore, it becomes clear that not only can the same effects as described above be obtained, but also that the change in resistance value of the resistance circuit can be arbitrarily set by the pattern shape of the second thin film resistors 9a to 9e.

[Brief explanation of drawings]

1 to 6 each show a conventional polishing apparatus for a thin film magnetic head, FIGS. 1 and 2 are plan views when an optical polishing amount monitor is used, and FIGS. 3 to 6 show a polishing apparatus for a conventional thin film magnetic head. Each shows the case where an electric polishing amount monitor is used, each a is a plan view, each b is a relationship diagram between the polishing amount and resistance value, and the following drawings are a polishing apparatus for a thin film magnetic head of the present invention. 7 and 8 are plan views of the main parts of one embodiment and diagrams of the relationship between the amount of polishing and the resistance value, and FIGS. 9 and 10 are the main parts of other embodiments. FIG. 3 is a plan view and a relationship diagram between the amount of polishing and the resistance value. 8a to 8e...first thin film resistor, 9a to 9e...
...Second thin film resistor, 10...Comb-shaped thin film conductor, 12
A, 12B... Electrode, 13a to 13e... Comb lead body portion, P... Polished surface.

Claims (1)

[Claims] 1 On the substrate on which the thin film magnetic head body is formed,
a plurality of first thin film resistors disposed at positions with increasing distances from the polished surface of the substrate, which are removed by polishing the substrate, change in resistance value, and eventually break, and each of the first thin film resistors; A plurality of second thin film resistors are paired with each other and the resistance value does not change at the same time as the first thin film resistors of each pair are removed by polishing, and each of the first thin film resistors is short-circuited on both sides. has an electrode that is long in the polishing progress direction and a comb tip that passes between each of the first thin film resistors, and connects the first and second thin film resistors in each pair in series, and connects each of the two thin film resistors in parallel. A polishing device for a thin film magnetic head, characterized in that a comb-like thin film conductor is formed.