JP3250720B2 - Mask alignment method for wafer for thin film magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for aligning a mask with respect to a wafer for a thin film magnetic head.

[0002]

2. Description of the Related Art In recent years, as hard disk drives have become smaller and higher in density, smaller magnetic heads, improved electromagnetic conversion efficiency, and lower impedance have been required, and thin-film magnetic heads and composite MR heads have been used. I have.

A thin-film magnetic head is manufactured by using a wafer and applying a high-precision pattern thin-film forming technique mainly based on photolithography on the wafer, similarly to the semiconductor manufacturing technology. In the photolithography process, it is common practice to perform a photo process for forming an element by performing a photomask alignment on an alignment pattern formed on a wafer in a previous photolithography process. I have. On the wafer, an alignment pattern called a target and the thin-film element formed in the previous step are provided. The target and the thin-film element are formed so as to maintain a predetermined fixed relative relationship.

[0004] The photomask includes keys for automatic alignment with the target and optical windows that define the dimensions of the thin film element to be obtained. The optical window maintains a predetermined relationship with the center of the key.

In aligning a photomask with a target on a wafer, conventionally, the center of the key of the photomask is aligned with the center of the target.
For the center alignment, an automatic alignment device is used. The center of the target is detected through the key of the photomask using the automatic alignment device, and the center of the key of the photomask is aligned with the detected center of the target. These scans are all performed automatically.

[0006]

One of the problems of the above-described conventional alignment method is that when the area of a target and a thin-film element formed on a wafer becomes large or small, the thin film becomes thin. It is caused by the position of the edge of the element fluctuating accordingly. In the photolithography process of forming the target and the thin-film element, the center position of the target and the thin-film element may be considered not to change, but their area may change. In the conventional method of aligning the center of the photomask with the center of the target when the area of the thin film element changes, the relative position of the optical window on the photomask with respect to the existing thin film element changes. Changes the position of the thin film element to be created. This position fluctuation causes fluctuations in the MR height and the throat height in the thin-film magnetic head, and fluctuates the electromagnetic conversion characteristics.

For example, in the case of forming an insulating film which directly affects the definition of the throat height in an inductive magnetic transducer, a concave portion is formed in a substrate in a preceding process mainly for the purpose of eliminating a coil step. This recess is formed on the wafer together with the target. The insulating film is formed on the above-described recess. In the photolithography process for forming the target and the concave portion, when the pattern of the concave portion becomes large, the center position of the both does not change, but the edge position of the concave portion moves outward. Therefore, in the conventional method of aligning the center of the photomask with the center of the target, the position of the end of the concave portion changes relatively to the position of the end of the optical window provided on the photomask. Therefore, the position of the insulating film with respect to the concave portion changes. This position fluctuation causes a fluctuation in the throat height in the thin-film magnetic head, and fluctuates the electromagnetic conversion characteristics. The variation of the MR height can be explained similarly.

It is an object of the present invention to provide a mask alignment method capable of securing a constant MR height irrespective of pattern variations of a target and a thin film element formed on a wafer.

Another object of the present invention is to provide a mask alignment method capable of securing a constant throat height irrespective of pattern fluctuations of a target and a thin film element formed on a wafer.

[0010]

In order to solve the above-mentioned problems, one of the positioning methods according to the present invention is to perform photomask positioning for forming a magnetoresistive film on a wafer for a thin film magnetic head. Pertaining to the method of doing. The wafer has at least one target and a thin film element, and the target and the thin film element are formed using the same photomask.

On the other hand, the other photomask has a key and an optical window, and the optical window maintains a predetermined relationship with the center of the key. The optical window according to the present invention includes not only an optically transmissive area but also an optically opaque area.

Using the wafer and the photomask, the photomask is positioned with respect to the wafer such that the center of the key is aligned with the edge of the target, and the shape of the optical window allows the magnetoresistive film to be positioned. Determine the pattern.

In positioning the photomask with respect to the target on the wafer, the photomask is moved on the wafer in the directions of the X-axis and the Y-axis, which are two orthogonal axes, using an automatic positioning device. Then, the edge of the target is detected through the key of the photomask, and the center of the key of the photomask is aligned with the detected edge of the target. These scans are all performed automatically.

When the area of the target and the thin film element formed on the wafer increases or decreases, the center position of the target and the thin film element does not change. It changes according to the fluctuation of. Since the target and the thin-film element on the wafer are both formed using the same photomask, the amount of change in the position of the edge is the same for both the target and the thin-film element.

Therefore, the center of the photomask key is
Rather than aligning the center of the target, the photomask is positioned relative to the wafer according to the changed target edge. As a result, the position of the optical window changes with the key, the amount of change in the edge of the existing thin film element is absorbed, and the position of the optical window with respect to the existing thin film element is corrected so that the edge does not fluctuate. You. Then, the pattern of the magnetoresistive film is determined by the shape of the optical window.
Since the obtained magnetoresistive film has a predetermined constant relationship with the target and the thin film element in the previous step, a predetermined constant MR height can be reliably ensured.

Another alignment method according to the present invention relates to a method of aligning a photomask for forming an insulating film for determining a slot height of an inductive magnetic transducer on a wafer for a thin film magnetic head. Related. The wafer has at least one target and a thin film element. The target and the thin film element are created using the same photomask. On the other hand, the photomask has a key and an optical window, and the optical window maintains a predetermined relationship with the center of the key.

Using the wafer and the photomask, the photomask is positioned with respect to the wafer by aligning the center of the key with the edge of the target, and the pattern of the insulating film is determined by the shape of the optical window. Determine.

In positioning the photomask with respect to the target on the wafer, as described above, the center of the target is detected through the key of the photomask using the automatic positioning device, and the detected target is detected. Align the center of

When the area of the target and the thin-film element formed on the wafer becomes large or small, the center position of the target and the thin-film element does not change. It changes according to the fluctuation of. Since the target and the thin-film element on the wafer are both formed using the same photomask, the amount of change in the position of the edge is the same for both the target and the insulating film.

Therefore, the center of the key of the photomask is
Rather than aligning the center of the target, the photomask is positioned relative to the wafer according to the changed target edge. As a result, the position of the optical window changes with the key, the amount of change in the edge of the existing thin film element is absorbed, and the position of the optical window with respect to the existing thin film element is corrected so that the edge does not fluctuate. You. The pattern of the insulating film is determined by the shape of the optical window. The obtained insulating film has a predetermined constant relationship with the target and the thin-film element, so that a predetermined constant throat height can be reliably ensured.

[0021]

FIG. 1 is a sectional view of a thin film magnetic head to which a positioning method according to the present invention is applied. In the figures, the dimensions are exaggerated. The illustrated thin-film magnetic head includes a slider 1, an inductive magnetic transducer 2, and a magnetoresistive magnetic transducer (hereinafter referred to as an MR element) 3. The slider 1 shown in the embodiment has a structure in which an insulating film 102 such as Al ₂ O ₃ is adhered on a base 101 made of Al ₂ O ₃ —TiC or the like. The MR element 3 and the inductive magnetic transducer 2 are stacked on the insulating film 102. The insulating film 102 is made of M
A recess 103 is provided on the surface behind the region where the R element 3 is provided, and the lower shield film 10 is provided on the surface of the recess 103.
4 are attached. The inductive magnetic transducer 2 is stacked above the concave portion 103, whereby the thickness is reduced.

The magnetic transducers 2 and 3 are provided at the end of the slider 1 in the medium movement direction a1. Medium moving direction a
1 coincides with the outflow direction of the air that follows when the medium moves at high speed. The inductive magnetic transducer 2 is a recording element, and the MR element 3 is a reproducing element.

Inductive magnetic transducer 2 serving as a recording element
Are lower magnetic layer 21, upper magnetic layer 22, coil film 23, gap film 24 made of alumina or the like, and insulating films 251 and 252 made of organic resin such as novolak resin. And a protective film (not shown) made of alumina or the like.

The distal end portions of the lower magnetic layer 21 and the upper magnetic layer 22 are a lower pole portion P1 and an upper pole portion P2 opposed to each other with a gap film 24 having a very small thickness, and the lower pole portion P1 and the upper pole portion P2 are opposed to each other. The writing is performed in. The lower magnetic layer 21 and the upper magnetic layer 22 are connected to each other so as to complete a magnetic circuit at a rear connecting portion (not shown) whose yoke portion is opposite to the lower pole portion P1 and the upper pole portion P2. I have. The upper pole portion P2 has an air bearing surface 100 on which the tip surface is located.
And rises upward at a distance TH1 from the camera. The distance TH1 is called a throat height, and plays an important role in determining the electromagnetic conversion characteristics of the inductive magnetic conversion element 2. The throat height TH1 is directly affected by the edge position of the insulating film 252.

On the insulating films 251 and 252, a coil film 23 is formed so as to spiral around a rear connection portion (not shown). The number of turns and the number of layers of the coil film 23 are arbitrary. According to the inductive magnetic transducer 2 having the above structure, a high-efficiency thin-film magnetic circuit is formed, and a recording magnetic field generated from the pole portions P1 and P2 located at the tip ends causes a magnetic recording medium (not shown) to be formed. Magnetic recording can be performed.

As the MR element 3, various films having various film structures have been proposed and put to practical use. For example, there are a film using an anisotropic magnetoresistive film made of permalloy or the like, a film using a giant magnetoresistive (GMR) film such as a spin valve film, and the like. In the present invention, a high reproduction output independent of the speed of the recording medium can be obtained by using any type of MR element.

As a specific example of the MR element 3, a lead conductor film 31 including a magnetic domain control film is provided in a passive region on both sides of a magnetoresistive film (hereinafter referred to as an MR film) 30. The magnetic domain control film included in the lead conductor film 31 is a permanent magnet film,
It can be configured as a laminated film of a permanent magnet film and a nonmagnetic conductive film, or a laminated film of an antiferromagnetic film and a ferromagnetic film.

The MR element 3 includes a lower shield layer 104,
It is arranged between the insulating films 321 and 322 between the lower magnetic layer 21 also serving as the upper shield layer.

The MR element 3 has a dimension Hm with reference to the air bearing surface 100 where the tip is located. The dimension Hm is called an MR height, and plays an important role in determining the electromagnetic conversion characteristics of the MR element 3.

As described above, the present invention discloses a technique for setting the throat height TH1 and the MR height Hm with high accuracy.

Next, a description will be given of a method of aligning the thin-film magnetic head shown in FIG. 1 to obtain a highly accurate MR height Hm. First, a wafer 4 as shown in FIG. 2 is used, and a high-precision pattern thin film forming technique centering on photolithography is applied on the wafer 4. In FIG. 2, Q is a number of thin film devices arranged on the wafer 4. The thin film element Q has a structure according to a wafer process. Wafer 4 orientation for initial alignment. It has a straight portion 41 called a flat.

In one photolithography step, a photomask is aligned with the alignment pattern formed on the wafer in the previous photolithography step, and a photo process for forming elements is performed. When forming a composite MR head, it is necessary to first form an alignment pattern on an underlayer on a non-magnetic substrate. However, when performing the first alignment, since there is no previously formed pattern, the position and inclination of the wafer are determined by the linear portion 41 (see FIG. 2) formed on the substrate, and the alignment is performed with the mechanical accuracy of the exposure machine. Do. The next step is executed according to the pattern formed at that time. Then, a target for the next step is created for each step, and each step is executed with reference to this target.

FIG. 3 is an enlarged view of one of the thin film elements Q shown in FIG. This figure shows a state where a target 5 and a concave portion 103 are formed on a wafer 4. The insulating film 321 and the MR film (see FIG. 1) are already provided on the surface of the concave portion 103. However, the MR film is not patterned and is in a solid film state. Target 5
Is an edge 51 on an extension of the X-axis direction passing through the center C11,
It has 52. The lengths of the edges 51, 52 are equal to each other. In addition, the target 5 has a protruding portion 53 in the direction of the Y axis passing through the center C11 and orthogonal to the X axis. Center C11
The upper (in the figure) region is a rectangular shape surrounded by side edges 54, 55 and an upper end 56 extending from the ends of the edges 51, 52. The concave portion 103 has the target 5
Maintains a fixed relationship with the center C11. This relative relationship does not change even if the areas of the target 5 and the concave portion 103 change.

FIG. 4 is a plan view of a photomask. The illustrated photomask 7 includes a key 8 for alignment with the target 5 (FIG. 3) and an optical window 9 defining the final pattern of the MR element. The optical window 9 is located at the center C21 of the key 8, for example, at the center C22.
Maintain a predetermined relationship. The key 8 shown in the embodiment has a cross shape, and the optical window 9 has a rectangular optical transmission area. In the embodiment, the optical window 9 is shown as an optically transmissive area. However, the opposite optical pattern, that is, an optically opaque area may be used as described above. is there.

FIG. 5 is a view showing the alignment of the photomask 7 shown in FIG. 4 with respect to the wafer 4 shown in FIG. When aligning the photomask 7 with respect to the target 5 on the wafer 4, the photomask 7 is moved on the wafer 4 in the directions of the X axis and the Y axis, which are two orthogonal axes, using an automatic alignment device. And the photomask 7
, The edges 51 to 53 of the target 5 are detected, and the center C21 of the key 8 of the photomask 7 is aligned with the detected edges 51 to 53 of the target 5. These scans are all performed automatically. Thus, the optical window 9 that defines the pattern of the MR element is
The edge is aligned with a predetermined position of the interval Ho from the edge of the concave portion 103.

Next, a case where the area of the target 5 and the concave portion 103 formed on the wafer 4 is increased or decreased will be described.

FIG. 6 shows a case where the areas of the target 5 and the concave portion 103 are increased. When the area of the target 5 and the concave portion 103 formed on the wafer 4 increases, the center position of the target 5 and the concave portion 103 does not change, but the position of the edge with respect to the center position changes according to the change in the area. It changes by the change amount △ Ho. Since the target 5 and the concave portion 103 on the wafer 4 are both formed by using the same photomask and by the same photolithography process, the change amount ΔHo of the edge position is obtained.
Is the same in both the target 5 and the recess 103.

FIG. 7 is a view showing the alignment of the photomask 7 shown in FIG. 4 with respect to the wafer 4 shown in FIG. As shown in the figure, in the present invention, the center C21 of the key 8 of the photomask 7 is not aligned with the center of the target 5, but the edges 51 to 5 of the target 5 are set.
In accordance with 3, the photomask 7 is positioned with respect to the wafer 4. More specifically, in the Y-axis direction, the center C21 is aligned with the edges 51 and 52, and X
In the axial direction, the center C21 is located at an intermediate portion between the side edges 54 and 55.
Align.

Thus, the position of the optical window 9 is
At the same time, the optical window 9 changes by the change amount ΔHo, and the position of the optical window 9 with respect to the existing recess 103 is corrected to the interval Ho before the edges 51 to 53 change.

Depending on the shape of the optical window 9, the MR film 30 (FIG. 1)
Reference) pattern is defined. Since the obtained MR film 30 is formed with a predetermined constant interval Ho with respect to the concave portion 103, a predetermined constant MR height can be reliably ensured. Before the alignment in FIG. 7,
The surface of the wafer 4 is coated with a photoresist, and the photoresist is exposed through an optical window 9 according to the pattern.

FIG. 8 is a diagram showing a conventional alignment method as a comparative example of FIG. As shown in the figure,
With respect to the center C11 of the target 5, the photomask 7
The center C21 of the key 8 was aligned. In the photolithography process for forming the target 5 and the concave portion 103, when the area of the target 5 and the concave portion 103 changes, the center C21 of the key 8 of the photomask 7 is aligned with the center C11 of the target 5 by the conventional method. The relative position of the optical window 9 with respect to the edge changes from the interval Ho to the interval H1 approaching the concave portion 103 by a change amount ΔHo. This causes a fluctuation in the MR height, and fluctuates the electromagnetic conversion characteristics.

FIG. 9 shows a case where the areas of the target 5 and the concave portion 103 formed on the wafer 4 are reduced. Also in this case, the center position of the target 5 and the concave portion 103 does not change, but the position of the edge with respect to the center position changes. Target 5 and recess 1 on wafer 4
The amount of change ΔHo of the position of the edge of 03 is the same in both the target 5 and the recess 103.

FIG. 10 is a view showing the alignment of the photomask 7 shown in FIG. 4 with respect to the wafer 4 shown in FIG. The center C21 of the key 8 of the photomask 7 is
The wafer 4 is aligned with the edges 51 to 53 of the target 5.
Of the photomask 7 with respect to.

FIG. 11 is a diagram showing a conventional alignment method as a comparative example of FIG. As shown in the figure, in the photolithography process for forming the target 5 and the concave portion 103, when the area of the target 5 and the concave portion 103 is changed, the conventional method of aligning the center of the photomask with the center of the target is used. The relative position of the optical window 9 with respect to the edge changes from the interval Ho to the interval H1 that is away from the recess 103 by the change amount ΔHo. This causes a fluctuation in the MR height, and fluctuates the electromagnetic conversion characteristics.

FIG. 12 is a view showing another example of a target to be formed on a wafer. In the figure, the same components as those shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted. The target 5 has a rectangular concave portion 500 and a rod-shaped convex portion 501. Convex part 502
Are the upper edge 503 and the lower edge 504 located in the Y-axis direction.
Is formed so as to extend in the Y-axis direction at a position bisecting. Side edges 502 and 505 are located between the upper edge 503 and the lower edge 504.

FIG. 13 is a view showing a photomask conforming to the target shown in FIG. The key 8 has two light-opaque regions 81 and 82 arranged in parallel in the light-transmitting region 80 at a distance d1 in the Y-axis direction, and further above the light-opaque regions 81 and 82 (see FIG. ) Are provided with light opaque regions 83 and 84. Light opaque area 83,
Reference numeral 84 is arranged so as to have symmetry with respect to a center C21 in the Y-axis direction that divides the length of the light-opaque regions 81 and 82 in the X-axis direction into two.

FIG. 14 is a view showing the alignment of the photomask 7 shown in FIG. 13 with respect to the wafer 4 shown in FIG. First, in the alignment in the Y-axis direction, the center between the light opaque regions 81 and 82 is aligned with the edge of the lower edge 504 of the concave portion 500 constituting the target 5. X
In the axial alignment, the convex portion 501 is aligned with the intermediate portion C21 at the interval formed between the light-impermeable regions 83 and 84.

FIG. 15 shows a case where the areas of the target 5 and the concave portion 103 are increased. Target 5 and recess 1
In No. 03, the position of the edge extends outward by ΔHo.

FIG. 16 is a view showing the alignment of the photomask 7 shown in FIG. 14 with respect to the wafer 4 shown in FIG. In the alignment in the Y-axis direction, the center between the light-impermeable regions 81 and 82 is aligned with the edge of the lower edge 504 of the concave portion 500 constituting the target 5. In the alignment in the X-axis direction, the convex portions 501 are
3 and 84 are arranged in the intermediate portion C21 at an interval formed between them.

FIG. 17 shows a case where the areas of the target 5 and the concave portion 103 are reduced. Target 5 and recess 1
In No. 03, the position of the edge is reduced inward by ΔHo.

FIG. 18 is a view showing the alignment of the photomask 7 shown in FIG. 14 with respect to the wafer 4 shown in FIG. In the alignment in the Y-axis direction, the center between the light-impermeable regions 81 and 82 is aligned with the edge of the lower edge 504 of the concave portion 500 forming the target 5. In the alignment in the X-axis direction, the convex portion 501 is disposed at the intermediate portion C21 at the interval formed between the light-impermeable regions 83 and 84.

FIG. 19 is a view showing another example of the target 5 to be formed on the wafer 4. In the figure, the same components as those shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted. The target 5 has a recess 50
0, and the base of the concave portion 500 is a side 50 of an isosceles triangle.
1, 502.

FIG. 20 is a view showing a photomask 7 conforming to the target 5 shown in FIG. The key 8 has an isosceles triangular light impermeable area 80 in the light transmissive area 80.
Has zero. The light opaque region 800 is formed in an isosceles triangular shape conforming to the isosceles 501 and 502 constituting the base of the target 5, and has isosceles 801 and 802 and a base 803.

FIG. 21 is a view showing the alignment of the photomask 7 shown in FIG. 20 with respect to the wafer 4 shown in FIG. Mask alignment is performed by aligning the isosceles 801 and 802 of the key 8 provided on the photomask 7 with the isosceles 501 and 502 constituting the bottom of the target 5.

FIG. 22 shows a case where the areas of the target 5 and the concave portion 103 are increased. Target 5 and recess 1
In No. 03, the position of the edge extends outward by ΔHo.

FIG. 23 is a view showing the alignment of the photomask 7 shown in FIG. 20 with respect to the wafer 4 shown in FIG. Mask alignment is performed by aligning the isosceles 801 and 802 of the key 8 provided on the photomask 7 with the isosceles 501 and 502 constituting the bottom of the target 5.

The case where the area of the target 5 and the concave portion 103 is reduced can be easily estimated by those skilled in the art from the above description, and therefore, illustration and description are omitted.

Next, a description will be given of a method of positioning the thin-film magnetic head shown in FIG. 1 for obtaining a high-precision throat height.

FIG. 24 is an enlarged view of one of the thin film elements Q shown in FIG. This figure shows a state where an MR element 30, an insulating film 251, a coil film 23, and an insulating film 24 serving as a gap film are formed together with the target 5 on the wafer 4. The target 5 is formed using the same mask as when the MR element 30 was formed. Therefore,
The target 5 and the MR element 30 can be regarded as being substantially produced in the same process, and the two 5 and 30 maintain a predetermined fixed relative relationship.
The target 5 has edges 51 and 52 on an extension in the X-axis direction passing through the center C11. The lengths of the edges 51, 52 are equal to each other. In addition, the target 5 has a protruding portion 53 in the direction of the Y axis passing through the center C11 and orthogonal to the X axis. The area below the center C11 (in the figure) has a rectangular shape surrounded by side edges 54, 55 and a lower edge 56 extending from the ends of the edges 51, 52.

FIG. 25 is a plan view of a photomask. The illustrated photomask 7 includes a key 8 for alignment with the target 5 (FIG. 3) and an optical window 9 that defines the final pattern of the insulating film 252. The optical window 9 keeps a predetermined relationship with the center C21 of the key 8. The key 8 shown in the embodiment has a cross shape, and the optical window 9 has a remaining pattern for the insulating film 252 (see FIG. 1).

FIG. 26 is a view showing the alignment of the photomask 7 shown in FIG. 25 with respect to the wafer 4 shown in FIG. In positioning the photomask 7 with respect to the target 5 on the wafer 4, the photomask 7 is placed on the wafer 4 at right angles by using an automatic positioning device.
It is moved in the directions of the X axis and the Y axis. Then, the edges 51 to 51 of the target 5 are passed through the keys 8 of the photomask 7.
53 are detected, and the detected edges 51 to 5 of the target 5 are detected.
3, the center C21 of the key 8 of the photomask 7 is aligned.

Next, a case where the areas of the target 5 and the MR element 30 formed on the wafer 4 are changed will be described.
explain.

FIG. 27 shows a case where the areas of the target 5 and the MR element 30 are increased. When the area of the target 5 and the MR element 30 formed on the wafer 4 becomes large, the center position of the target 5 and the MR element 30 does not change, but the position of the edge with respect to the center position changes according to the change in the area. Change. Since the target 5 and the MR element 30 on the wafer 4 are both formed using the same photomask, the amount of change in the position of the edge is
The amount is the same for both the target 5 and the MR element 30.

FIG. 28 is a view showing the alignment of the photomask 7 shown in FIG. 20 with respect to the wafer 4 shown in FIG. As shown, in the present invention, the center C21 of the key 8 of the photomask 7 is
Of the target 5 instead of being centered
The photomask 7 is positioned with respect to the wafer 4 according to 1 to 53. As a result, the position of the optical window 9 changes together with the key 8 by the change amount ΔHo, and the existing M
The position of the optical window 9 with respect to the R element 30 is corrected to the uniform interval Ho of the edge.

The edge position of the optical window 9 defines the throat height TH1 (see FIG. 1). In the MR head, the element X is polished with reference to the MR element 30 or a dummy prepared in the same manner as the MR element. As described above, the insulating film 252
The position of the MR element 30 with respect to the edge of the optical window 9 which determines the edge position of the optical element 9 is set to the position of the interval Ho regardless of the pattern variation of the MR element 30. Therefore, the position of the insulating film 252 that determines the throat height TH1 can be accurately positioned, and a constant throat height TH1 can be secured. Target 5 and MR formed on wafer 4
A description of the case where the area of the element 30 is reduced will be omitted because it can be easily estimated from the above description.

FIG. 29 is a diagram showing a conventional alignment method as a comparative example of FIG. As shown in the figure, in the photolithography process for producing the target 5 and the MR element 30, when the area of the target 5 and the MR element 30 changes, the center of the photomask is aligned with the center of the target. In this method, the MR element 30
Of the optical window 9 relative to the edge of the MR element 30 from the distance Ho by a variation ΔHo from the distance Ho.
It changes to 1. This causes fluctuation of the throat height TH1 and fluctuates the electromagnetic conversion characteristics.

The embodiments described above are merely representative and do not limit the scope of the claims. For example, the target 5 may have an inverted concavo-convex pattern, or may adopt various other pattern shapes.

[0068]

As described above, according to the present invention, the following effects can be obtained. (A) It is possible to provide a mask positioning method capable of securing a constant MR height irrespective of pattern variations of a target and a thin film element formed on a wafer. (B) It is possible to provide a mask alignment method capable of securing a constant throat height irrespective of pattern fluctuations of a target and a thin film element formed on a wafer.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a thin-film magnetic head to which a positioning method according to the present invention is applied.

FIG. 2 shows a wafer to which the alignment method according to the present invention is applied.

FIG. 3 is an enlarged view of one of the thin film elements Q shown in FIG. 2;

FIG. 4 is a plan view of a photomask.

FIG. 5 is a view showing the alignment of the photomask shown in FIG. 4 with respect to the wafer shown in FIG. 3;

FIG. 6 is a diagram illustrating a case where the areas of a target and a concave portion are increased.

FIG. 7 is a view showing the alignment of the photomask shown in FIG. 4 with respect to the wafer shown in FIG. 5;

FIG. 8 is a diagram showing a conventional alignment method as a comparative example of FIG. 7;

FIG. 9 is a diagram showing a case where the areas of a target and a concave portion formed on a wafer are reduced.

FIG. 10 is a view showing the alignment of the photomask shown in FIG. 4 with respect to the wafer shown in FIG. 9;

11 is a diagram showing a conventional alignment method as a comparative example of FIG.

FIG. 12 is a diagram showing another example of a target to be formed on a wafer.

FIG. 13 is a diagram showing a photomask that matches the target shown in FIG.

FIG. 14 is a view showing the alignment of the photomask shown in FIG. 13 with respect to the wafer shown in FIG. 12;

FIG. 15 is a diagram showing a case where the areas of the target and the concave portion are increased.

FIG. 16 is a view showing the alignment of the photomask shown in FIG. 14 with respect to the wafer shown in FIG. 15;

FIG. 17 is a diagram showing a case where the areas of the target and the concave portion are reduced.

18 is a diagram illustrating alignment of the photomask illustrated in FIG. 14 with respect to the wafer illustrated in FIG. 17;

FIG. 19 is a diagram showing another example of a target to be formed on a wafer.

FIG. 20 is a diagram showing a photomask that matches the target shown in FIG.

21 is a diagram illustrating the alignment of the photomask illustrated in FIG. 20 with respect to the wafer illustrated in FIG. 19;

FIG. 22 is a diagram illustrating a case where the areas of the target and the concave portion are increased.

23 is a diagram illustrating alignment of the photomask illustrated in FIG. 20 with respect to the wafer illustrated in FIG. 22;

FIG. 24 is an enlarged view of one of the thin film elements shown in FIG. 2;

FIG. 25 is a plan view of a photomask.

FIG. 26 is a view showing the alignment of the photomask shown in FIG. 25 with respect to the wafer shown in FIG. 24;

FIG. 27 is a diagram showing a case where the areas of the target and the MR element on the wafer are increased.

FIG. 28 shows the wafer 4 shown in FIG. 27 with respect to FIG.
FIG. 7 is a view showing the alignment of the photomask 7 shown in FIG.

FIG. 29 is a diagram showing a conventional alignment method as a comparative example of FIG. 28;

[Explanation of symbols]

 4 Wafer 5 Target 51-55, 501, 502 Edge 7 Photomask 8 Key 9 Optical Window

Claims (3)

(57) [Claims] 1. A method for aligning a photomask for forming a magnetoresistive effect element on a wafer for a thin film magnetic head, wherein the wafer has at least one target and a thin film element, The target and the thin film element are formed by applying a photolithography process using one photomask, and the target has a concave portion or a convex portion, and the concave portion or the convex portion is formed on the wafer. Another photomask includes a key and an optical window, the edge including an edge along at least one of two imaginary orthogonal axes, and the key includes an optically transparent part and an opaque part. And an optical pattern obtained by said optical window, said optical window having a center defined by said optical pattern. A excessive region, with respect to the center of the key, and maintaining the predetermined relationship, the center of the key, of the other photomask with respect to the wafer in accordance with the said end edge of said target A photomask alignment method including a step of performing positioning and defining a pattern of the magnetoresistive element according to a shape of the optical window. 2. A method of aligning a photomask for forming an insulating film defining a throat height of an inductive magnetic transducer on a wafer for a thin-film magnetic head, the wafer comprising: at least one target; A thin film element, the target and the thin film element are formed by applying a photolithography process using one photomask, and the target has a concave portion or a convex portion, The concave portion or the convex portion includes an edge along at least one direction of two orthogonal axes imagined on the wafer, another photomask includes a key, and an optical window, and the key includes: Having an optical pattern obtained by an optically transparent portion and an opaque portion, and having a center determined by the optical pattern; Is an optically transmissive area or an optically opaque area, which maintains a predetermined relationship with the center of the key, and aligns the center of the key with the edge of the target. And positioning the other photomask with respect to the wafer, and defining the pattern of the insulating film by the shape of the optical window. 3. A method according to claim 2, wherein said method includes a step according to claim 1 as a preceding step.