JPH02236809A - Production of thin-film magnetic head - Google Patents

Abstract

PURPOSE:To prevent the collapse of conductor coil patterns by softening of org. insulating films which support the conductor coil films by forming the org. insulating films of a photoresist of a novolak resin system on a substrate in 3 stages of curing processes in a prescribed temp. range. CONSTITUTION:A lower magnetic film 2 and a gap film 3 are formed on the substrate 1 and further, a positive type resist film 61 consisting of the photoresist of the novolak resin system is applied and is subjected to soft baking under the conditions of 90 deg.C and 30 minutes and is then subjected to exposing, developing and rinsing processings. In the 1st stage, the photoresist is thereafter heat-treated at 120 to 140 deg.C just before the 1st softening temp. at which the photoresist of the novolak resin system causes thermal softening to preliminarily cure the same. In the 2nd stage, the photoresist is heat-treated at 170 to 190 deg.C just before the 2nd softening temp. and is thereby preliminarily cured. In the next 3rd stage, the photoresist is heat-treated at 200 to 320 deg.C lower than the thermal decomposition temp. of the novolak resin and is thereby finally cured. The curing processes of the org. insulating films 62, 63 are executed similarly. The org. insulating films 61 to 63 are thus thermally cured without generating thermal softening therein.

Description

Detailed Description of the Invention Industrial Field of Application The present invention relates to a method of manufacturing a thin film magnetic head for in-plane recording/reproduction or perpendicular recording/reproduction. When forming using a photoresist, the curing process is performed in the first step.
20℃~140℃, the next second stage is 170℃~190℃
By making the next third step a three-step curing process at 200°C to 320°C, the insulating film made of novolak resin photoresist is cured without being softened in the curing process, and the conductor is formed by softening the insulating film. This is to prevent the pattern of the coil film from collapsing.

BACKGROUND ART Two types of thin film magnetic heads are known: one for in-plane recording and reproduction and one for perpendicular recording and reproduction. FIG. 1 is a sectional view of the main parts of a conventionally known thin film magnetic head for in-plane recording and reproducing, in which 1 is a base, 2 is a lower magnetic film, 3 is a gap film made of alumina or the like, 4 is an upper magnetic film, 51 and 52 are conductor coil films, 61 to 63 are organic insulating films made of novolac resin photoresist, and 7 is a protective film made of alumina or the like.

The base 1 is a ceramic base 10 made of Al203, TiC, etc.
It has a structure in which an insulating film 102 made of alumina or the like is deposited on the substrate 1.

The tips of the lower magnetic film 2 and the upper magnetic film 4 are formed by a gap film 3.
There are ball parts 21 and 41 facing each other with a distance between them, and reading and writing are performed in these ball parts 21 and 41. The yoke parts 22 and 42 that are continuous with the ball parts 21 and 41 are connected to each other at a joining part on the opposite side from the ball parts 21 and 41.

The conductor coil films 51 and 52 are arranged so as to spiral around the above-mentioned coupling portion, and are connected to each other in series.

The above-mentioned thin film magnetic head is manufactured by a thin film pattern forming technique called photolithography. Among the manufacturing steps, the steps for forming the conductive coil film and the organic insulating film are schematically shown in FIG.

First, in the process shown in FIG. 2(a), a lower magnetic film 2 and a gap film 3 are formed on a substrate 1, and then a negative type or positive type resist film 61 made of novolac resin photoresist is coated. , soft bake for 30 minutes, and then perform exposure, development, and water washing. Subsequently, heat treatment at 130°C for 1 hour and 220°C,
The organic insulating film 61 is formed by performing heat treatment for one hour. Therefore, the curing process of organic insulation 11!61 is as follows:
This is a two-stage curing process, with the first stage at 130°C and the second stage at 220°C.

Next, in the step shown in FIG. 2(b), a C U /Ti material is sputtered on the surface of the organic insulating film 61 to form a base conductor film 51A.

Next, as shown in FIG. 2(c), a negative or positive resist film 62A is applied to the surface of the base conductor film 51A, and
After soft-baking at 30° C. for 30 minutes, the photomass 8 is positioned on the resist film 62A and exposed, as shown in FIG. 2(d). As a result, an exposure pattern matching the pattern of the photomask 8 is obtained, as shown in FIG. 2(e). Next, as shown in FIG. 2(f), the Cu plating film 51B
is attached to the removed portion 62B of the resist film 62A to a thickness of, for example, 2.5 μm. Next, the resist film 62A is peeled off, and the base conductor @51A under the peeled resist film 62A is removed by ion milling, and as shown in FIG.
A conductive coil film 51 is formed on J61. Thereafter, the steps shown in FIGS. 2(a) to 2(f) are repeated to form an organic anti-green film 62, a conductive coil film 52, and an organic insulating film 63 in a laminated manner. Then, the upper magnetic film shown in FIG. 1 is formed on the surface of the organic insulating film 63, and a protective film is deposited thereon by means such as sputtering. However, in the conventional manufacturing method using a two-step curing process, the pattern of the organic insulating films 61 to 63 collapses, which causes the pattern of the conductor coil films 51 and 52 to collapse. It was found that this led to collapse, causing wire breaks and short circuits. The cause of the pattern collapse of the organic insulating films 61 to 63 is presumed to be as follows.

The novolak resin-based photoresist constituting the organic insulating films 61 to 63 has extremely complex characteristics, such as being thermosoftening or thermosetting depending on the temperature conditions. Conventionally, for novolac resin photoresists having such complex characteristics, the first step 130 is
℃, and the second stage was 220℃, so the softening temperature conditions for the novolac resin photoresist were met in the curing process, causing the novolac resin photoresist to flow and cause pattern collapse. It is assumed that.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for manufacturing a thin film magnetic head in which an insulating film made of a novolac resin photoresist is hardened without softening, and pattern collapse of a conductive coil film due to softening of the insulating film is prevented. That's true.

Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention provides a method for forming an organic insulating film supporting a conductive coil film on a substrate using a novolac resin photoresist. The film is characterized by being formed in a three-step curing process: the first stage is 120°C to 140°C, the second stage is 1°C to 190°C, and the third stage is 200°C to 320°C. do.

It was found that the novolak resin photoresist has a first softening temperature and a second softening temperature higher than the first softening temperature. These softening temperatures depend on the type of photosensitive resin added to the novolac resin, but the first softening temperature is 140°C.
It was also found that the second softening temperature was around 190°C. It was also found that the novolak resin itself undergoes thermal decomposition when the temperature exceeds 320°C.

Therefore, in the first step, the present invention aims at 120°C, which is just before the first softening temperature at which the novolak resin photoresist undergoes thermal softening.
The novolac resin photoresist is preliminarily cured by heat treatment at a temperature of 140°C to 140°C.

In the next second step, heat treatment is performed at a temperature of 170° C. to 190° C., exceeding the first softening temperature and just before the second softening temperature, to preliminarily harden the material.

Then, in the next third step, heat treatment is performed at 200 to 320° C., which exceeds the second softening temperature and is lower than the thermal decomposition temperature of the novolac resin, to finally cure it.

Therefore, according to the present invention, a novolac resin photoresist can be cured without causing softening, flow, or pattern collapse, and an organic insulating film having a predetermined pattern can be formed.

For example, to explain the case of forming an organic insulating film 61, in the process shown in FIG. Positive resist film 6
1 was coated, soft-baked at 90° C. for 30 minutes, exposed, developed and washed with water.

After this, conventionally 80℃! Heat treatment for hours and 220℃
The organic insulating film 61 was formed by performing heat treatment for 1 hour and 1 hour, but in the present invention, the first step is performed at 120 °C to 1 hour.
40℃, the next second stage is 170℃~190℃, the next third stage
The curing process is a three-stage curing process with stages ranging from 200°C to 320°C.

Appropriate time conditions are approximately 1 hour for each stage.

The curing process for the organic insulating films 62 and 63 is performed in the same manner. Therefore, according to the present invention, the organic insulating films 61 to 63 can be thermally hardened without causing thermal softening.

The present invention is applicable not only to a thin film magnetic head for in-plane recording/reproduction.
It can also be applied to thin-film magnetic heads for perpendicular recording and reproduction. <Effects of the Invention> As described above, the method for manufacturing a thin film magnetic head according to the present invention includes the following steps when forming an organic insulating film supporting a conductive coil film on a base using a novolac resin photoresist. The organic insulating film has a temperature of 120°C to 140°C in the first stage,
The next second stage is 170℃~190℃, the next third stage is 2
Since it is formed using a three-step curing process at 00°C to 320°C, the insulating film made of novolac resin photoresist is cured without softening, and pattern collapse of the conductor coil film due to softening of the insulating film is prevented. A method for manufacturing a thin film magnetic head can be provided.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a thin film magnetic head, and FIGS. 2(a) to 2(g) are sectional views showing the manufacturing process of the thin film magnetic head. 1... Base 2... Lower magnetic film 5, 51,
52... Conductor coil film 61-63... Organic insulating film

Claims (1)

[Claims] When forming an organic insulating film that supports the conductor coil film on the base using a novolac resin photoresist,
The organic insulating film is formed at temperatures of 120°C to 140°C in the first stage, 170°C to 190°C in the second stage, and 20°C in the third stage.
A method for manufacturing a thin film magnetic head, characterized in that it is formed in a three-step curing process at 0°C to 320°C.