JP3120596B2 - Method of forming photoresist pattern for manufacturing 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 forming a positive photoresist pattern when manufacturing a thin film magnetic head.

[0002]

2. Description of the Related Art When manufacturing a thin film magnetic head, a step of forming a photoresist pattern is frequently performed.

FIG. 4 shows a conventional photoresist pattern forming process of this type.

For example, when a thin film pattern is formed by a mask method, first, a thin film layer 40 is formed on the entire surface of a substrate,
A photoresist layer 41 is formed by applying a photoresist on the entire surface and pre-baking. Then
As shown in FIG. 4A, exposure is performed with the exposure mask 42 superposed. Thereafter, as shown in FIG. 4B, a photoresist pattern 43 is formed by performing development or the like.

[0005] The photoresist pattern 43 thus obtained is subjected to a heat treatment to enhance its adhesiveness and to improve its heat resistance. This heat treatment step is generally called post bake. After the post-baking, an etching step and a photoresist stripping step are performed to finally form a thin film pattern.

[0006]

However, since the positive photoresist pattern 43 has thermal softening properties, it is easily deformed by heat during post-baking.
As shown in (C), an inclination (sag) 44 often occurs at the edge 43a. If such dripping 44 occurs at the edge portion of the photoresist pattern 43, a processing error occurs in the subsequent fine processing such as dry etching, and cracks occur in the protective film in a film forming process such as plating. Problem.

Accordingly, the present invention provides a method of forming a photoresist pattern for manufacturing a thin-film magnetic head in which such sagging does not occur at the edge of the photoresist pattern.

[0008]

According to the present invention, a photoresist film is formed by forming a positive photoresist film, exposing the formed photoresist film to a predetermined pattern, developing the photoresist film, and then performing a heat treatment. Provided is a novel method of forming a photoresist pattern for manufacturing a thin-film magnetic head. According to this method, a groove or a recess extending along the edge of the photoresist pattern before the heat treatment is formed at a position separated by a predetermined distance of 2 μm or less from the edge.

If a groove or recess extending along the edge of the photoresist pattern before the heat treatment is formed at a predetermined distance of 2 μm or less from the edge of the photoresist pattern, heat treatment, that is, post-baking is performed. However, no sagging occurs at the edges.

The above-mentioned groove or recess is exposed by using an exposure mask having a mask pattern corresponding to a photoresist pattern to be formed and a slit near the edge of the mask pattern and extending along the edge. It is preferable to form it.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a photoresist pattern forming step in one embodiment of the present invention, and FIG. 2 is a plan view showing a part of an exposure mask used for forming the photoresist pattern. In this embodiment, as an example, a thin film pattern of a thin film magnetic head is formed by a mask method.

First, a photoresist of a positive type is applied on a thin film layer 10 formed on the entire surface of a substrate and prebaked (pre-dried) to form a photoresist layer 11.

Next, as shown in FIG. 1A, exposure is performed with the exposure mask 12 superposed. This exposure mask 1
2, along the edges 120a, 120b, and 120c near the edges 120a, 120b, and 120c of the mask pattern 120 corresponding to the photoresist pattern to be formed, as shown in FIG. Running slits (slits for sagging prevention patterns) 121, 122,
And 123 are provided respectively. Each edge 120
a, 120b, and 120c and each slit 121, 12
The distance from the edge of each of 2 and 123 is kept at 2 μm or less.

After performing normal exposure using such an exposure mask 12 and performing development and the like, a photoresist pattern 13 as shown in FIG. 1B is formed. That is,
Due to the light passing through the slits 121, 122, and 123, the photoresist pattern 13 has grooves or recesses (drips) running along the edge 13a at a predetermined distance of 2 μm or less from the edge 13a. (Prevention pattern) 14 is formed. Moreover, the photoresist layer is never penetrated at the groove 14 so that unnecessary pattern defects do not occur.

In order to make the photoresist layer non-penetrating at the groove 14, the slits 121, 122,
And the slit width of 123 are the conditions (resist thickness,
Exposure amount, etc.). That is, when the slit width is increased, the light energy passing through the slit increases, and when the slit width is reduced, the light energy passing through the slit decreases. Therefore, if the slit width is appropriately selected so that light energy is passed through which a groove is formed but not penetrated, penetration at the groove portion does not occur even when ordinary exposure and development steps are performed.

The photoresist pattern 13 thus obtained is post-baked to enhance its adhesiveness and heat resistance. FIG. 1C shows the photoresist pattern 13 after post-baking. As is apparent from FIG. 3, the edge 13 of the photoresist pattern 13 despite the post-baking.
The part a is kept standing, and there is almost no inclination (sag). This allows the groove 14 to be
This is because it is provided near 3a.

FIG. 3 is a view for explaining the reason. FIG. 3A shows a photoresist pattern after a development step.
(B) shows the photoresist pattern after post-baking it. Even when post-baking is performed under the same conditions using the same photoresist, the manner of sagging differs depending on the width of the photoresist pattern. The degree of sag is much smaller in the narrow photoresist pattern 30 than in the wide photoresist pattern 31 due to the surface tension, and the sag becomes smaller as the pattern width becomes narrower. Generally, when the pattern width W is 10 μm or more, a droop 32 that cannot be ignored occurs.

As a post-bake post-process, a dry etching process and a photoresist stripping process are performed to form a thin film pattern. However, in this embodiment, since the photoresist pattern 13 hardly sags, a highly accurate fine pattern is formed. Processing becomes possible.

FIG. 5 is a graph showing the relationship between the groove position, that is, the distance from the edge 13a of the photoresist pattern 13 to the edge of the groove 14, and the angle (sag) of the resist pattern. As shown in the figure, when a wide photoresist pattern is formed as in the pattern formation of the thin film magnetic head, if the distance from the edge 13a of the photoresist pattern 13 to the edge of the groove 14 exceeds 2 μm, the resist pattern is It can be seen that the angle becomes smaller (the sag becomes larger) and the processing accuracy of the pattern decreases.

In the embodiment described above, the mask method is used to form the groove 14. However, in the present invention, the same groove may be formed by any other method, for example, an ion beam method. It is clear.

In the above-described embodiment, the case where a thin film pattern is formed by a mask method has been described. However, the present invention is not limited to the step of forming a positive type photoresist pattern. It can be applied to the film forming process or any other process, and it is possible to prevent the sagging of the photoresist pattern and to perform high-precision fine processing and to suppress the occurrence of cracks in the protective film (when plating is performed in the subsequent process). Is what you do. In particular, the present invention is very effective in preventing sagging when a wide photoresist pattern is formed as in the case of forming a pattern of a thin film magnetic head.

[0023]

As described above in detail, according to the present invention, a positive photoresist film is formed, and the formed photoresist film is exposed to a predetermined pattern, developed, and then heat-treated. When a photoresist pattern for manufacturing a magnetic head is formed, a groove extending along the edge of the photoresist pattern before heat treatment is formed at a position separated by a predetermined distance of 2 μm or less from the edge of the photoresist pattern. When forming a wide photoresist pattern as in the case of forming a pattern of a thin-film magnetic head, sagging does not occur at the edge of the photoresist pattern even if post baking is performed. As a result, it is possible to improve processing accuracy and reliability in subsequent steps.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating a photoresist pattern forming step according to an embodiment of the present invention.

FIG. 2 is a plan view showing a part of an exposure mask in the embodiment of FIG.

FIG. 3 is a diagram for explaining the reason why sagging does not occur in the embodiment of FIG. 1;

FIG. 4 is a partial cross-sectional view illustrating a conventional photoresist pattern forming process.

FIG. 5 is a graph showing a relationship between a groove position and an angle of a photoresist pattern.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Thin film layer 11 Photoresist film 12 Exposure mask 13, 30, 31 Photoresist pattern 13a, 120a, 120b, 120c Edge 14 Groove 32 Drip 120 Mask pattern 121, 122, 123 Slit

Claims (2)

(57) [Claims] 1. A method of forming a photoresist pattern by forming a positive photoresist film, exposing the formed photoresist film to a predetermined pattern, developing the photoresist film, and then performing a heat treatment to form a photoresist pattern. Forming a groove extending along the edge of the photoresist pattern at a predetermined distance of 2 μm or less from the edge of the photoresist pattern. 2. The groove is formed by using an exposure mask having a mask pattern corresponding to a photoresist pattern to be formed and a slit extending along the edge near the edge of the mask pattern during the exposure. The method of claim 1, wherein: