JP2677399B2 - Method for manufacturing thin-film magnetic head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin film magnetic head, and a wafer formed by aligning a number of thin film magnetic head elements is cut to arrange the thin film magnetic head elements side by side. The head assembly is taken out in rows, and the surface layer of the cut surface of the taken head assembly is thermally annealed to reduce the processing strain in the surface layer of the cut surface and reduce the influence of the processing strain. This is to eliminate the pattern bending of the thin film magnetic head element of the unit, to efficiently control the gap depth, and to improve the flatness of the air bearing surface.

<Prior Art> A thin film magnetic head is formed by aligning and forming a number of thin film magnetic head elements on a single wafer, cutting the wafer to take out a head assembly in a row unit, and then taking out the head assembly. The head assembly is manufactured by subjecting the head assembly to grooving, polishing, etc., which are necessary for the slider, and then subjecting each thin film magnetic head element to an independent cutting process. FIG. 2 is a diagram showing a manufacturing process of the thin film magnetic head. First, as shown in FIG. 2 (a), thin film magnetic head elements are aligned and formed on a wafer 1 to be a slider. The pad portions (41A, 42A), (41B, 42B) of each thin film magnetic head element are led out to the surface of the protective film 3 on the wafer 1.

Then, set the cutting position during each row H ₁ ~H _n (X ₁
The wafer 1 is cut at −X ₁ ) to (X _{n + 1} −X _{n + 1} ) and the head assembly as shown in FIG. 2B is taken out. Figure 2 (b) shows a head assembly of the cutting position (X ₄ -X ₄₎ and the cutting position (X ₅ -X ₅₎ with cut column H _4.

Next, the head assembly thus taken out is subjected to grooving processing, polishing processing, etc. necessary for a slider, and then (Y ₁ -Y ₁ ) to (Y _n −
Cut with Y _n ).

FIG. 3 is a perspective view of a thin-film magnetic head manufactured through the above-described manufacturing process. Two rail portions 101 and 102 are provided on the medium facing surface side of the slider 1 which is a wafer and are spaced apart from each other.
And the surfaces of the rail portions 101, 102 are air bearing surfaces 103, 104 having a high degree of flatness, and the thin film magnetic head elements 2A, 2B are carried at the ends of the rail portions 101, 102 in the air outflow direction a. It will be the structure. As the thin-film magnetic head, there have been proposed those in which the medium facing surface is flat without a rail portion, those in which only one thin-film magnetic head element is used, and the like.

The thin film magnetic head elements 2A, 2B are formed on the wafer 1 according to a process similar to IC manufacturing technology. FIG. 4 is an enlarged cross-sectional view of a thin film magnetic head element for in-plane recording / reproducing, where 21 is a lower magnetic film made of permalloy or the like, 22 is an insulating gap film made of Al ₂ O ₃ , SiC or the like, 23 , 24 are conductor coil films, 25 to 27 are interlayer insulating films formed of photoresist or the like, and 28 is an upper magnetic film made of permalloy or the like. 3 is a protective film, which is a thin film magnetic head element
The conductor coil films 23 and 24 of 2A and 2B respectively are pad portions (41A and 42) for connecting external conductors formed on the surface of the protective film 3.
A) and (41B, 42B) are conductively connected. As the thin-film magnetic head elements 2A and 2B, in addition to the above-described in-plane recording / reproducing, those for perpendicular recording / reproducing are also known.

<Problems to be Solved by the Invention> However, as shown in FIG. 2 (a), the wafer 1 is cut at the cutting positions (X ₁ −X ₁ ) to (X _{n + 1} −X _{n + 1} ). When the head assembly is obtained, processing distortion occurs on the cut surfaces (a) and (b). Due to this processing distortion, the head assembly shown in FIG. 2B has a problem that the pattern of the thin film magnetic head element is bent.

In the final product thin film magnetic head shown in FIG.
There is a problem that the flatness of the air bearing surfaces 103 and 104 is affected by processing strain, and the flatness of the air bearing surfaces 103 and 104 is impaired. The deformation of the air bearing surfaces 103, 104 due to the processing strain is such that the air bearing surfaces 103, 104 are concave, so that the traveling property with the medium deteriorates. FIG. 5 is a diagram showing the flatness of the air bearing surfaces 103 and 104 of the thin film magnetic head shown in FIG. 3, which has a concave shape due to the balance of processing strain.

<Means for Solving Problems> In order to solve the conventional problems described above, according to the present invention, a plurality of thin film magnetic head elements are aligned and formed on one wafer, and then the wafer is cut. And a step of taking out the head assembly in which the thin film magnetic head elements are arranged side by side, and a step of thermally annealing the surface layer on the cut surface of the taken out head assembly.

<Operation> As described with reference to FIG. 2A, after the thin-film magnetic head elements are aligned and formed on the wafer 1, the cutting positions (X) set between the rows H _{1 to} H _n are set. ₁ −X ₁ ) 〜 (X _{n + 1} −
The wafer 1 is cut with (X _{n + 1} ), and the head assembly as shown in FIG. 2B is taken out. In the present invention, the head layer thus taken out is subjected to thermal annealing on the surface layer of the cut surface. This alleviates the processing strain in the surface layer of the cut surface. The main purpose of the thermal annealing in the present invention is to alleviate and homogenize working strain, but it can also be applied as a flatness adjusting means.

FIG. 1 is a diagram showing a thermal annealing process by laser annealing. In the figure, 1 is a wafer serving as a slider,
2A and 2B are thin film magnetic head elements, (41A, 42A), (41B, 4
2B) shows a pad portion for connecting an outer conductor, and 5 shows a laser beam. The thermal annealing is performed by irradiating the laser beam 5 by a YAG laser or the like to the cut surface (a) on the side opposite to the cut surface (b) which becomes the medium facing surface in the air or an inert gas atmosphere. Since the cutting surface (b) facing the cutting surface (a) is a medium facing surface where the pole portions of the thin film magnetic head elements 2A and 2B appear, it is inappropriate to perform the thermal annealing treatment. By this thermal annealing, the stress distribution on the cut surface (a) is diffused and the processing strain is relaxed. In the thermal annealing, the laser beam 5 is scanned relative to the head assembly as shown by arrow b, and the laser beam 5 is operated so as to hit the cut surface (a) on average.

The thermal annealing only needs to alleviate the processing strain occurring in the cut surface (a). The processing strain of the cut surface (a) is the depth h = 0.
It often occurs in the surface layer of 05 to 5 μm. Therefore, the laser beam 5 is applied under the intensity and time conditions that allow the thermal annealing of the cut surface (a) at the depth described above. If the intensity or the irradiation amount of the laser beam 5 becomes excessive, the wafer 1 may be melted or cracked. Since the thermal annealing needs to be limited to the surface layer of the cut surface (a), the laser beam 5 is suitable as the thermal annealing means. Besides the laser beam, an electron beam or the like can be applied.

After the thermal annealing process, according to the conventional process, the thin film magnetic head is obtained by cutting along the cutting lines (Y ₁ -Y ₁ ) to (Y ₅ -Y ₅ ).

FIG. 6 is data showing the flatness of the air bearing surface of the thin film magnetic head (see FIG. 3) obtained through the thermal annealing process. As shown in this data, the air bearing surface is a forward crown that is convex upward.

<Effects of the Invention> As described above, in the method of manufacturing a thin film magnetic head according to the present invention, after a large number of thin film magnetic head elements are aligned and formed on one wafer, the wafer is cut and the head is cut. Since it includes a step of taking out the aggregates in units of rows and a step of subjecting the surface layer of the cut surface of the taken-out head aggregates to thermal annealing, a thin film having high precision flatness and no bending of the head pattern. A magnetic head can be manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram showing steps of essential parts in a method of manufacturing a thin film magnetic head according to the present invention, FIGS. 2 (a) and 2 (b) are diagrams showing manufacturing steps of a thin film magnetic head, and FIG. FIG. 4 is a perspective view of the head, FIG. 4 is an enlarged cross-sectional view of the vicinity of a thin film magnetic head element, FIG. 5 is a view showing the flatness of the air bearing surface of the thin film magnetic head obtained by a conventional manufacturing method, and FIG. FIG. 6 is a diagram showing the flatness of the air bearing surface of the thin film magnetic head obtained by the manufacturing method according to the first embodiment. 1 ... Wafer 2A, 2B ... Thin film magnetic head element 5 ... Laser beam H _{1 to} H _n・ ・ ・ Row (a) ・ ・ ・ Cut plane

Claims (2)

(57) [Claims] 1. A step of aligning and forming a number of thin film magnetic head elements on a single wafer, and then cutting the wafer to take out a head assembly row by row, and a head taken out through the above steps. And a step of thermally annealing the surface layer of the cut surface of the aggregate, the method of manufacturing a thin-film magnetic head. 2. The method of manufacturing a thin film magnetic head according to claim 1, wherein the thermal annealing is laser annealing.