JP2752447B2 - Method for manufacturing thin-film magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to the manufacture of a thin-film magnetic head in which a plurality of thin-film magnetic head elements having substantially the same pattern are aligned and formed on one wafer. About the method.

<Prior Art> A thin film magnetic head is manufactured by a high-precision pattern forming technique called photolithography. In forming a pattern by photolithography, a photoresist is applied on a wafer by means of spin coating or the like, and after performing necessary processing steps such as soft baking, a substantially identical pattern is formed for each thin film magnetic head element. Exposure is performed using a photomask having The finally obtained pattern of each thin film magnetic head element is defined by this exposure pattern.

<Problems to be solved by the invention> However, in the conventional photolithography process,
There has been a problem that the pattern variation between the thin-film magnetic head elements is large and the yield is low. In the case of a thin film magnetic head, in particular, variations in the pole width are fatal.
The following points can be considered as causes of pattern variation between the thin film magnetic head elements.

(A) In a photolithography process, when a photoresist is spin-coated on a wafer, it is almost impossible to make the thickness of the applied photoresist uniform over the entire surface of the wafer so that there is no difference. The main cause of the variation in the thickness of the photoresist is a difference in flow resistance to the photoresist depending on the arrangement direction of the thin film magnetic head elements on the wafer.
Therefore, when a pattern is formed for each thin-film magnetic head element by exposing with a photomask, a thin-film magnetic head element located at a thick portion of a photoresist coating film and a thin-film magnetic head element located at a thin portion are formed. In this case, a difference occurs in the light diffraction effect and the light absorption amount. For this reason, the effective exposure amount fluctuates, and the pattern varies. In particular, when the upper pole for determining the track width of the thin-film magnetic head is formed, the convex portions due to the elements of the wafer become large, and the variation becomes large.

(B) The warpage of the wafer also causes a difference in the diffraction of light, causing the same pattern fluctuation.

(C) It is difficult to obtain an ideal light source that is completely parallel and has the same light intensity. For this reason, a difference occurs in the exposure distribution, and the pattern varies.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems and to improve the pattern of the thin-film magnetic head element caused by the position on the wafer. An object of the present invention is to provide a method of manufacturing a thin-film magnetic head capable of forming a thin-film magnetic head element having a uniform pattern with a reduced yield and a high yield.

<Means for Solving the Problems> In order to solve the above-described problems, in manufacturing a thin film magnetic head according to the present invention, a plurality of thin film magnetic head elements having substantially the same pattern are aligned on one wafer. And forming. In the step, a photoresist is applied on the wafer by a spin coating method, and the photoresist is exposed using a photomask that has been subjected to pattern correction according to the position of the thin-film magnetic head element on the wafer. A step of correcting a variation in the area of the exposure pattern due to a resist film thickness, an exposure distribution, a warpage of the wafer, and the like due to the position of the thin-film magnetic head element on the wafer.

<Operation> After a photoresist is coated on a wafer by spin coating, the photoresist is exposed using a photomask that has been subjected to pattern correction according to the position of the thin-film magnetic head element on the wafer, and is exposed on the wafer. Variations in the area of the exposure pattern due to the resist film thickness, exposure distribution, and wafer warpage due to the position of the thin-film magnetic head element are corrected, so that a thin-film magnetic head element having a uniform pattern can be formed at a high yield.

Is hitting the preparation of <Example> thin film magnetic head, the Al ₂ O ₃ -TiC such thin-film magnetic head element assembly number on a wafer made of a ceramic structure formed by aligning a number of thin-film magnetic head element After manufacturing, a manufacturing process is performed in which the thin film head assembly is cut to take out a single thin film magnetic head element.

FIG. 1 is a model diagram showing an arrangement of thin-film magnetic head elements on a wafer, wherein 1 is a wafer made of a ceramic structure such as Al ₂ O ₃ —TiC, and Q 1 to Qn are thin films formed on the wafer 1. It is a magnetic head element.

FIG. 2 is a perspective view of an essential part of each of the thin-film magnetic head elements Q1 to Qn, 2 is a lower magnetic film, 21 is a pole part thereof, 22 is a yoke part, 3 is a gap film made of alumina or the like,
Is an upper magnetic film which is substantially similar to the lower magnetic film 2; 41 is its pole portion; 42 is its yoke portion; 5 is a conductor coil film; 6 is an insulating film made of an organic insulating resin such as novolak resin; , 8 are draw-out lead portions.

FIG. 3 is a cross-sectional view showing the main structure of each of the thin-film magnetic head elements Q1 to Qn. The lower magnetic film 2 is formed on a substrate 1 with a plating under film 9 interposed therebetween. The conductor coil films 51 and 52 and the insulating films 61 to 63 are formed by laminating on the gap film 3 formed on the conductor film 2, and plating is performed on the insulating film 63 formed on the conductor coil film 5. Through the ground film 10,
An upper magnetic film 4 is formed.

The lower magnetic film 2 and the upper magnetic film 4 form a pole portion 21-41 serving as a medium facing surface by a magnetic gap G1 formed by the gap film 3.
And the yoke portions 22-42 are magnetically coupled to each other at the rear end side, and the conductor coil films 51 and 52 are spirally formed around the joint portion.

As described above, the thin-film magnetic head elements Q1 to Qn are formed based on a high-precision pattern forming technique by photolithography. FIG. 4 schematically shows a step of forming the upper magnetic film 4 by plating.

First, as shown in FIG. 4 (a), after forming a gap film 3, a conductor coil film 5 and an insulating film 6 on the lower magnetic film 2 by photolithography, the gap film 3 and the outermost insulating film are formed. A plating base film 10 is provided on exposed portions such as 63 and the surface of the substrate 1.

Next, as shown in FIG. 4B, a photoresist 11 is applied to the surface of the plating base film 10. Photoresist 11
Is applied by spin coating. FIG. 5 is a view showing spin coating, in which the wafer 1 is rotated in the direction of arrow a, and the photoresist is moved by centrifugal force at that time.
11 is made to flow and diffuse from the rotation center to the outer peripheral direction as shown by the arrow b. The arrow C with the thin-film magnetic head elements Q1 to Qn indicates the direction of the pole. The photoresist 11 may be either positive or negative.

Next, as shown in FIG.
A photomask 12 is positioned on the substrate, exposed, and developed. By this patterning by photolithography, a resist frame 13 of photoresist is formed as shown in FIG. 4 (d). Resist frame
13 is formed so that the pattern formed on the inside thereof becomes the pattern of the upper magnetic film 4 finally obtained.

Next, as shown in FIG.
Using 13 as a mask, a frame plating process is performed, and pattern plating 14 is performed. Of the pattern plating 14, the pattern plating 14 in a region surrounded by the resist frame 13 becomes the upper magnetic film. The frame plating process mainly includes a plating process for forming a yoke portion,
Usually, it is a two-step plating process of forming a pole portion while plating on the surface of the yoke portion.

Thereafter, the frame resist and the plating outside the frame resist are removed by means such as ion milling and chemical etching, and the protective film is sputtered.

However, since the thin-film magnetic head elements Q1 to Qn are arranged on the wafer 1 so that the pole directions thereof are all in the same direction, the photoresist 11 is spin-coated as shown in FIG. When the coating is performed by using the photoresist 11, the flow resistance of the pole forming portion with respect to the photoresist 11 is determined in one region (a) with the center line X passing through the rotation axis O1 as a boundary.
And the group Qm + 1 to Qn of the thin-film magnetic head elements belonging to the other region (b) have different flow resistances to the photoresist 11.

That is, the group Q1 of the thin-film magnetic head elements belonging to the region (a)
QQm, the flow diffusion direction b of the photoresist 11 by the spin coating is opposite to the pole direction C, and the thin film magnetic head element group Qm + 1 belonging to the region (b)
In Qn, the pole direction C is the direction along the flow diffusion direction b of the photoresist 11 by spin coating. Before and after the pole direction c, the outer peripheral shape of the insulating film 6 is different as shown in FIG. Therefore, a region (a) where the pole direction C is opposite to the diffusion direction b of the photoresist 11,
In the area (b) facing the pole direction, the photoresist 11
The flow resistance to the

For this reason, as shown in FIG. 4C, when the photomask 12 is positioned on the photoresist 11, exposed, and developed, the thin film magnetic head elements Q1 to Qn are exposed as the photomask 12. When the patterns are the same, the thickness of the photoresist 11 applied to the pole portions of the thin film magnetic head elements Qm + 1 to Qn belonging to the area (b) is h1, and the thickness of the thin film magnetic head element belonging to the area (a) is h1. Between the thickness h2 of the photoresist 11 applied to the pole portions of the groups Q1 to Qm,
See FIG. 6 (a) for the thickness difference Δh. Due to this thickness difference Δh, as shown in FIG. 6B, when a photomask 12 is applied, the distance d1 between the photomask 12 and the surface of the photoresist 11 varies by the thickness difference Δh. As shown in FIG. 7, the exposure width fluctuates from the width W1 to the width W2, which causes a change in the pole width of the upper magnetic film, that is, the track width and the electromagnetic conversion characteristics.

Therefore, in the present invention, in the step of FIG.
When exposing using the photomask 12, exposure is performed using the photomask 12 that has been subjected to pattern correction according to the positions of the thin film magnetic head elements Q1 to Qn on the wafer 1. As a means of pattern correction, the exposure pattern is obtained by using a photomask 12 having the same pattern in each of the thin-film magnetic head elements Q1 to Qn, and then a thin-film magnetic head element Q1 to The pattern shape distribution of Qn is measured. FIG. 8 is a diagram showing the pole width distribution of the upper magnetic film of the preceding prototype obtained in this manner. Photo mask
The pole width of 12 was 13.0 μm. In FIG.
A1 is the distribution area with a pole width of 12.5-12.9 μm, B1 is the pole width
13.0 ~ 13.3μm distribution area, C1 is pole width 13.4 ~ 13.9μ
The distribution area of m is shown. If a photomask 12 having no pattern correction is used, a thin-film magnetic head element having a pole width variation distribution as shown in FIG. 8 will be manufactured.

Next, a photomask 12 having a pattern for correcting the distribution characteristics from the pole width distribution characteristics of the preceding prototype shown in FIG. 8 is manufactured. FIG. 9 shows an example of a photomask 12 which has been subjected to pattern correction for canceling the pole width distribution characteristic shown in FIG. 8, and A2 is for correcting the distribution area A1.
A region with a pole width of 13.5 μm, B2 is for correcting the distribution region B1 and has a pole width of 13.0 μm, and C2 is for correcting the distribution region C1 and has a distribution region with a pole width of 12.5 μm.

FIG. 10 shows a pole width distribution characteristic in a wafer surface when a photomask without pole width correction is used.
FIG. 11 shows the pole width distribution characteristics in the wafer surface when using the photomask with the pole width correction according to the present invention. 10 (a) is a pole width distribution characteristic in the area A1 in FIG. 8, FIG. 10 (b) is a pole width distribution characteristic in the same area B1, and FIG. 10 (c) is a pole width distribution characteristic in the same area C1. Is shown. FIG. 11 (a) shows the pole width distribution characteristics in the region A2 in FIG. 9, and FIG. 11 (b) shows the pole width distribution characteristics in the region B2.
FIG. 3C shows the pole width distribution characteristics in the region C2.

From the comparison between FIG. 10 and FIG. 11, when the photomask without pole width correction was used, the pole width distribution was in the range of 12.01 to 12.70 μm in average, but the pole width was corrected. By using the photomask, the pole width distribution is in the range of 12.43 to 12.53 μm on average, and it can be seen that the distribution characteristics are improved. Therefore,
Pattern of thin-film magnetic head element in wafer plane. Variations can be suppressed and a thin-film magnetic head having a uniform pattern can be manufactured with a high yield.

<Effects of the Invention> As described above, according to the present invention, the pattern of the thin-film magnetic head element in the plane of the wafer. Variations can be suppressed and a high yield of a thin film magnetic head having a uniform pattern can be manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a wafer for a thin-film magnetic head element, FIG. 2 is a perspective view of the thin-film magnetic head element, and FIG.
FIG. 4 is a cross-sectional view of the main part, FIG. 4 is a view showing a process of forming an upper magnetic film, FIG. 5 is a perspective view showing spin coating of a photoresist, and FIG. 6 is a problem in a frame forming process after spin coating. FIG. 7 shows points, and FIG.
FIG. 8B is a cross-sectional view taken along the line B1-B1 of FIG. 8B, FIG. 8 is a view showing a pole width distribution of an upper magnetic film of a preceding prototype using a photomask without pole width correction, and FIG. FIG. 10 shows an example of a photomask which has been subjected to a pattern correction for canceling the pole width distribution characteristic shown in FIG. 10. FIG. 10 shows a pole width distribution characteristic in the wafer surface when a photomask which has not been subjected to the pole width correction is used. FIG. 11 shows a pole width distribution characteristic in a wafer surface when a photomask corrected for pole width according to the present invention is used. DESCRIPTION OF SYMBOLS 1 ... Wafer 2 ... Lower magnetic film 3 ... Gap film 4 ... Upper magnetic film 5 ... Conductor coil film 6, 61-63 ... Insulating film 11 ... Photoresist and resist frame 21 ... Lower magnetic film Pole part 41 ... Pole part of upper magnetic film Q1 ~ Qn ... Thin film magnetic head element 12 ... Photomask

Claims (1)

(57) [Claims] 1. A method for manufacturing a thin-film magnetic head, comprising the step of aligning and forming a plurality of thin-film magnetic head elements having substantially the same pattern on one wafer, wherein said step is After applying a photoresist on the wafer by spin coating, using a photomask that has been subjected to a pattern correction according to the position of the thin-film magnetic head element on the wafer, exposing the photoresist, thereby, A method of manufacturing a thin film magnetic head, comprising: correcting a resist film thickness, an exposure distribution, and an exposure pattern area variation due to a warpage of a wafer due to a position of the thin film magnetic head element on the wafer.