JPH0467410A - Sectional form detecting method for pole of thin film magnetic head - Google Patents

Abstract

PURPOSE:To surely detect the sectional form of a pole by grinding the end surface of a pole part where its end part is to appear, and sampling the sectional form of the pole part appearing on the ground surface as coordinating it with a ground position, and detecting the sectional form of the pole seen from a direction perpendicular to the ground surface. CONSTITUTION:One of bar-shaped head aggregates H containing plural thin film magnetic head elements Qr1 to Qrq is stuck to a jig 9, and the end surface 2A where the pole parts 21, 41 are to appear is ground, and the sectional forms of the pole parts 21, 41 appearing on the ground surface 2A are sampled as being coordinated with the ground position, and the sectional forms of the poles seen from the direction perpendicular to the ground surface 2A are detected. Thus, the pole sectional form to be the basis required for setting throat height important in the electromagnetic conversion characteristic of the thin film magnetic head is surely detected.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for detecting the cross-sectional shape of a pole of a thin-film magnetic head. The polishing necessary to set the throat hide, which is important for the electromagnetic conversion characteristics of a thin-film magnetic head, can be performed by sampling the cross-sectional shape of the pole in a direction perpendicular to the polishing surface by sampling it in correspondence with the polishing position. This makes it possible to reliably detect the cross-sectional shape of the pole, which is the basis for determining the amount.

<Prior Art> In a thin film magnetic head, throat hide is one of the important elements that determines the electromagnetic conversion characteristics. Regarding the relationship between throathide and electromagnetic conversion characteristics, see, for example, JP-A-55-
It is described in Publication No. 84019. As disclosed in the above-mentioned publication, the thin film magnetic head has a pole portion facing each other with a gap film interposed therebetween, and a yoke portion continuous with the pole portion. The pole part has a distal end region formed substantially parallel to the surface of the ceramic structure, and a displacement region that stands up in a direction away from the surface of the ceramic structure, and the displacement region It connects to York via the The depth from the tip of the pole section to the point of displacement is usually called the throat hide or gap dibs. The throat hide has a minute size of, for example, about 1 μm, and is an extremely important part for determining electromagnetic conversion characteristics. Therefore, in order to obtain predetermined electromagnetic conversion characteristics, the throat hide must be set with high precision. If the throat hide deviates from the predetermined dimensions, it will result in a non-standard product, resulting in a decrease in yield.

Conventionally, as a means for setting the throat hide, the end face where the end of the pole portion appears is set in a predetermined position based on the processing mark provided for each thin-film magnetic head element in the state of the bed piece assembly made from the wafer on the first day. The throat hide was polished to the point where it could be obtained. The processing marks are attached to each thin-film magnetic head element in a predetermined positional relationship with respect to a displacement point that serves as a reference for determining the throat hide.

<Problems to be Solved by the Invention> However, the displacement point varies considerably from wafer to wafer due to mask misalignment in the photolithography process on the wafer, variations in the curing conditions of the glabella insulating film, etc. It is normal to do so. For this reason, the relative position of the displacement point with respect to the processing mark differs from wafer to wafer, and when setting the polishing amount based on the processing mark, it is extremely difficult to set the throat hide with high precision, which is a major obstacle to improving yield. It becomes.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems and to provide a pole cross-sectional shape detection method that can reliably detect the pole cross-sectional shape that is the basis for determining the amount of polishing required to set the throat hide. It is to provide.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention provides a method for detecting the cross-sectional shape of a pole of a thin-film magnetic head element provided on one surface of a ceramic structure, the method comprising: The end face where the end portion appears is polished, the cross-sectional shape of the pole portion appearing on the polished surface is sampled in correspondence with the polishing position, and the cross-sectional shape of the pole viewed in a direction perpendicular to the polished surface is detected. shall be.

The end face where the end of the pole part appears is polished, and the cross-sectional shape of the pole part that appears on the polished surface is sampled in correspondence with the polishing position, and the cross-sectional shape of the pole viewed in the direction perpendicular to the polished surface is detected. By doing this, we actually obtained a thin 1N! jMi
It is possible to know the cross-sectional shape of the pole of the air head element.

If the thin film magnetic head element is on the same wafer as the thin film magnetic head element subjected to this inspection process, the mask position,
Since it can be seen that the manufacturing conditions such as curing of the glabellar insulating film are the same, there will be no major error even if it is assumed that the poles have almost the same cross-sectional shape.

Therefore, by setting the amount of polishing of other thin film magnetic head elements in the same wafer based on the obtained pole cross-sectional shape, it becomes possible to set the throat hide with high precision and improve the yield.

<Embodiment> FIG. 1 shows an example of a method for detecting the cross-sectional shape of a pole of a thin-film magnetic head. Of Figure 1, Figures 1 (a) and (b)
also shows part of the typical manufacturing process for a thin air head. First, as shown in FIG. 1(a), a wafer 1 having a large number of thin film magnetic head elements Q1 to Q0 arranged in a grid on one side is manufactured. The wafer 1 is made of Al2O3, for example.
- It is composed of a ceramic structure such as TiC, and the thin film magnetic head elements Q1 to Q, 1 are formed on one side of the wafer 1 via an insulating film such as Al2O3.

As is well known, the thin film magnetic head elements Q1 to Qn are formed by high-precision pattern forming technology mainly based on photolithography. Figure 2 shows the thin film magnetic head element Q1~
The enlarged planar partial cutaway view of Qn, Figure 3, is also Figure 2A.
, -A, shows a cross-sectional view on the line. FIGS. 2 and 3 are shown on different scales. In the figure, a wafer 1 has an insulating film 1b made of Al2O deposited on the surface of a base 1a made of A1□03.TiC, and thin film magnetic head elements Q1 to Qn are formed on this insulating film 1b. . The thin film magnetic head elements Q1 to Q have a lower magnetic field @
2. It has a thin film laminated structure consisting of a gap @3, an upper magnetic film 4, a coil film 5, and an interlayer insulation @6, and the overall diameter is ^120. It has a structure in which it is covered with a protective film 7 such as.

The lower magnetic @2 and the upper magnetic film 4 have a pole portion 21.41 facing each other with the gap film 3 in between, and a yoke portion 22.42 continuous with the pole portion 21.41. The pole portion 41 of the upper magnetic film 4 stands up in the direction away from the surface of the wafer 1 behind the tip region 411 formed to be substantially parallel to the surface of the wafer 1 which is a ceramic structure. has a displacement region 412 and is connected to the yoke 42 via the displacement region 412. The depth Th from the tip of the pole portion 41 to the displacement point Y is called throat hide. Yoke 22 and yoke 42 are coupled in the rear region to complete the magnetic circuit.

Each of the thin film magnetic head elements Q1 to Qo has a processing mark 8, as shown in FIG. Processing mark 8
are attached to each of the thin film magnetic head elements Q1 to Qrl in a predetermined positional relationship with respect to the displacement point Y, which is a reference for determining the throat hide Th.

The explanation will be given again with reference to FIG. The wafer 1 is cut in columns at cutting positions (xo -xo) to (X,, -X,) to form a wafer containing a plurality of thin film magnetic head elements Qri to Qrq, as shown in FIG. 1(b). Take out the bar-shaped head assembly H.

Next, as shown in FIG. 1(C), one of the head assemblies H taken out is glued to the jig 9, and the pole part 21.41
The end face 2A where the end portion appears is polished, the cross-sectional shape of the pole portion 21.41 appearing on the polished surface 2A is sampled in correspondence with the polishing position, and the cross-sectional shape of the pole viewed in the direction perpendicular to the polished surface 2A is detected. Press.

Figure 4 is an enlarged view of the vicinity of the pole, and the polishing position is the base. ,Ill...ρ. When proceeding as follows, the thickness a of the pole' portion 21 is set at each polishing position from 0 to Un.
0 to an, the thickness boNbn of the gap film 3, and the thickness C0 to c of the pole portion 41 are measured. In many cases, the above-mentioned polishing is carried out at a displacement point Y, which is the standard for the throat hide Th.
Since the main purpose is to detect the final polishing position i
l.

may be a point slightly beyond the displacement point Y. 0 for each polishing position
~ρ. can be specified based on the position of the processing mark 8.

Moreover, the thickness aO to an of the pole part 21, the thickness b0 to bo of the gap @3, and the thickness c0 to Cn of the pole part 41 are as follows.
Can be detected by optical means. Polishing position 1°~iL,
l can also be taken as time information if the amount of polishing per unit time is constant. with these cross-sectional shape detection signals and polishing positions. By inputting the information of ~A into a computer, the cross-sectional shape of the pole viewed in a direction perpendicular to the polishing surface can be displayed as a graphic output.

If the bed piece assembly H is obtained from the same wafer as the bed piece assembly H subjected to this inspection process, it can be seen that the manufacturing conditions such as curing of the interlayer insulating film 5 are the same, so they are almost identical. Even if it is estimated that the pole has a cross-sectional shape of

Therefore, by setting the amount of polishing of other helad piece aggregates in the same Unibar based on the obtained pole cross-sectional shape, it becomes possible to set the throat hide Th with high precision and improve the yield. . As a technique for polishing the head piece assembly H, Japanese Patent Laid-Open No. 1-153264, Japanese Patent Laid-Open No. 1-153265, etc. are known.

In the embodiment, a thin film magnetic head having two elements is shown, but a structure having only one element may be used. Further, it can be applied to both a type having a rail on the medium facing surface side and a type having no rail.

<Effects of the Invention> As described above, the present invention polishes the end face where the end of the pole portion appears, samples the cross-sectional shape of the pole portion that appears on the polished surface in correspondence with the polishing position, and performs polishing. Since the cross-sectional shape of the pole viewed in the direction perpendicular to the surface is detected, the cross-sectional shape of the pole is the basis for determining the amount of polishing required to set the throat hide, which is important for the electromagnetic conversion characteristics of thin-film magnetic heads. A pole cross-sectional shape detection method that can be reliably detected can be provided.

[Brief explanation of drawings]

￥S1 Figures (a) to (c) are diagrams showing a method for detecting the pole cross-sectional shape of a tvsMi magnetic head according to the present invention, and Figure 2 is an enlarged planar partial cutaway view of a thin film magnetic head element on a wafer.
FIG. 3 is a sectional view taken along line A r A 1 in FIG. 2, and FIG. 4 is an enlarged view of the pole portion for explaining the pole cross-sectional shape detection method according to the present invention. 1...Wafer Ql-Qn...Thin film magnetic head element H...Head assembly C1, C2...Cross section (FIG. 1 Ic)

Claims (2)

[Claims] (1) A method for detecting the cross-sectional shape of a pole of a thin-film magnetic head element provided on one surface of a ceramic structure, the method comprising: polishing the end face where the end of the pole portion appears; and polishing the end face where the end of the pole portion appears on the polished surface. A method for detecting the cross-sectional shape of a pole in a thin-film magnetic head element, characterized in that the cross-sectional shape of the pole is sampled in correspondence with the polishing position, and the cross-sectional shape of the pole viewed in a direction perpendicular to the polishing surface is detected. (2) A pole cross section of the thin film magnetic head according to claim 1, wherein a plurality of the thin film magnetic head elements are arranged at intervals in the length direction on one surface of the rod-shaped ceramic structure. Shape detection method.