JPS61227183A - Flattening method - Google Patents

Abstract

PURPOSE:To flatten the surface of an SiO2 insulator in the stage of producing a thin film magnetic head by forming a photoresist on the surface of an SiO2 insulating film on a coil conductor layer on an insulator and subjecting the same to ion milling at a specific ion incident angle. CONSTITUTION:A lower magnetic layer 3 and the 1st insulating layer 2 are successively laminated on a substrate 4 and a multi-layer coil conductor layer 1 is provided thereon. The 2nd insulating layer 5 consisting of SiO2 is formed thereon by sputtering, etc. The SiO2 insulating layer 5 constitutes the surface having the ruggedness of the coil conductor layer 1 as it is and therefore the upper magnetic material 7 itself has the ruggedness in the stage of forming the upper magnetic layer 7 consisting of 'Sendust(R)', etc., thereon. The magnetic permeability of the magnetic material is thereby decreased. The photoresist 6 is thickly coated on such rugged SiO2 insulating layer 5 and is heat-treated at 130 deg.C and thereafter the resist is subjected to ion etching in such a manner that the ion incident angle is 30-50 deg., then 75 deg. to flatten the surface of the layer 5. The generation of the raggedness to the above-mentioned magnetic material 7 is thus prevented and the magnetic head having excellent magnetic characteristic is produced.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a planarization method that performs etching at an ion incidence angle that makes the etching rate of an uneven surface equal to that of an organic resin. The present invention relates to a flattening method that suppresses the occurrence of protrusions.

(Prior art) For example, in a thin film magnetic head in which an insulating layer of a lower magnetic layer cylinder 1, a single-layer or multilayer coil conductor layer, a second insulating layer, and an upper magnetic layer are sequentially laminated on a substrate, a coil The second insulating layer made of SiO2, etc., which is formed by sputtering or vapor deposition after forming the conductor layer, becomes an insulating layer with concavities and convexities because the underlying coil conductor layer has concavities and convexities. When an upper magnetic layer such as amorphous or sendust is formed using MII or the like, the magnetic material itself has irregularities, which lowers the magnetic permeability of the magnetic material and lowers the recording and reproducing efficiency of the magnetic head.

In order to avoid such a decrease in recording and reproducing efficiency, 11
g! The head is flattened. In other words, the insulating layer S! has irregularities! By applying a photoresist to a thickness of about 8 μm on the Oz layer, the unevenness of the underlying 5i02 insulating layer is filled and the surface of the photoresist is made smooth. Next, heat treatment is performed at 130°C or higher to improve the flatness of the photoresist surface, and then the ion incidence angle is adjusted so that the photoresist and the insulating layer S f O2 have the same etching rate. is the angle between the ion beam and the normal direction of the sample). After the insulating layer on the coil conductor layer is planarized in this manner, a magnetic material such as sendust or amorphous, which will become the upper magnetic pole, is formed by sputtering, vapor deposition, or the like. The 111M magnetic head formed in this way has no unevenness in the magnetic film because the magnetic material is formed on a flat surface, so the magnetic permeability of the magnetic film does not decrease, and the recording and reproducing efficiency is higher than that of a thin film magnetic head with unevenness. will improve.

However, this planarization method using an organic resin (hereinafter referred to as an etch-back method) has the following problems.

That is, in ion milling using an inert gas such as Ar gas, the photoresist and the insulating layer S
The ion incidence angle at which the etching rate of iO2 becomes equal is a larger angle (for example, about 75°) than the ion incidence angle at which the maximum etching rate of the photoresist is obtained (for example, around 55°). If etchback is performed at such a large ion incidence angle, minute impurities on the photoresist surface will become nuclei, and the etched photoresist will re-adhere to these nuclei, or the etched photoresist will become photoresist due to diffusion. As a result, protrusions are formed during etching of the photoresist due to redeposition and repolymerization on the resist surface, and when the 5fOz insulating layer is etched in this state, the etching rate of the photoresist and 5fOz increases. Because of this, the protrusions of the photoresist are transferred onto 5i02, and countless protrusions are formed on the insulating layer to be planarized. When a magnetic material such as amorphous or sendust is formed on this insulating layer by sputtering or vapor deposition, the problem arises that the magnetic material has unevenness due to the influence of the underlying layer, making it impossible to improve recording and reproducing efficiency. be.

(Objective of the Invention) The present invention has been made to solve the above problems, and aims to provide a flattening method that can obtain a smooth flat surface without protrusions or depressions using ion etching. This is the purpose.

(Structure of the Invention) In the flattening method of the present invention, after applying an organic resin to an uneven surface, the organic resin is heat-treated, and then ion milling is performed to first obtain the maximum etching rate of the organic resin. This method is characterized in that etching is performed at an ion incidence angle smaller than the ion incidence angle, and then etching is performed at an ion incidence angle such that the etching rates of the organic resin and the surface of the convex portion are equal.

(Example) An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram illustrating the manufacturing process of a thin film magnetic head. In the manufacturing process of the thin film magnetic head according to this embodiment, first, an uneven insulating layer 5 made of 5 iOz is formed on the coil conductor layer 1 (FIG. 1(b)), and a photoresist is applied on this insulating layer 5. 6 is applied to a thickness of about 8 μm, and then the photoresist 6 is heat-treated at 130° C. or higher (
Figure 1 (C)). Here, the coil conductor layer 1 is formed on a base formed by sequentially laminating a substrate 4, a lower magnetic layer 3, and a first insulating layer 2 (FIG. 1(a)).

The photoresist 6 thus formed is etched by ion milling (FIGS. 1(d) and 2). By the way, when the ion incidence angle θ is relatively small as shown in FIG.
is approximately 0.8μ7rL deep.

It becomes a conical depression with a diameter of about 10 μm, and as the ion incidence angle θ increases, the depth of the conical depression gradually becomes shallower. When the ion incidence angle θ is 35°, the depth of the depression is about 0.2 μm. degree.

Furthermore, when the ion incidence angle θ is 45°, both unevenness exists, and at angles greater than 45°, most of the unevenness is about 2μ in height.
It becomes a conical protrusion with a diameter of about 10 μm. Moreover, these protrusions only occur when etching is performed for a long time.
After several tens of minutes of etching time, hardly any convex projections are observed. Therefore, in this example, in consideration of the above results, in order to make the photoresist 6 a recess (within about 1 μm) that has almost no effect on the magnetic properties, the ion incidence angle θ was set to be larger than 30° and smaller than 45°. Most of the photoresist 6 is etched at a small angle, and then the ion incidence angle θ is set to 75° so that the etching rates of the photoresist 6 and the 5iOz insulating layer 5 are equal. Thereafter, sendust or amorphous magnetic material 18 is formed by sputtering, vapor deposition, etc. (FIG. 1(f)).

In addition, although the above-mentioned embodiment describes the case where the present invention is applied to a thin film magnetic head, the same effect can be obtained even when the present invention is applied to semiconductors and other devices that require planarization. Of course.

(Effects of the Invention) As explained above, according to the planarization method of the present invention, the first
The unevenness on the photoresist surface is made into an extremely shallow depression by the step-by-step planarization etching, and then the photoresist and the insulating layer are etched at the same speed in the second step, so there are no protrusions or depressions. A substantially flat insulating layer 5 can be obtained. Since the magnetic body 7 formed on the thus flattened insulating layer 5 has no unevenness, there is little deterioration in magnetic properties, and a remarkable effect can be achieved in that recording and reproducing efficiency can be improved.

[Brief explanation of drawings]

Figure 1 is a diagram showing the process of a thin film magnetic head, Figure 2 is an enlarged view of a part of Figure 1(d), and Figure 3 is a diagram showing the ion incidence angle and the size of the protrusion. , Figure 4 shows S!
FIG. 3 is a diagram showing the dependence of the etching rate of the Oz insulating layer and the photoresist on the ion incidence angle. 1... Coil conductor layer 2... Insulating layer 3...
・Lower magnetic layer 4...Substrate 5...Insulation
Layer 6...Photoresist...Top magnetic layer 8^, 8B...Protrusions Figure 1 Iont 1 inch angle θ Shun) Figure 4 A 1 inch angle e (cliff) (spontaneous) Procedures? m official document 1, indication of the case Japanese Patent Application No. 60-66211 2, method for flattening the name of the invention 3, relationship with the amendment cloth case Patent applicant 4, agent 5-2 Roppongi, Minato-ku, Tokyo No. 1 No. 6, number of inventions increased by amendment None 1) Insert ", J" in front of "Lower magnetic layer" on page 2, line 9 of Specification Kasumi. 2) Insert ", J" on page 7, lines 17-18 of the same.

Claims (2)

[Claims] (1) In a flattening method in which an organic resin is applied to an uneven surface, the organic resin is then heat-treated, and then flattened by ion milling, the organic resin is first etched with ions that obtain the maximum etching rate of the organic resin. A planarization method in which etching is performed at an angle smaller than a beam incident angle, and then etching is performed at an ion beam incident angle such that the etching rate of the organic resin and the surface of the convex portion are equal. (2) The uneven surface is formed of SiO_2, a photoresist is used as the organic resin, and after the photoresist is heat-treated at 130°C or higher, the ion incidence angle is greater than 30° and smaller than 45°. 2. The planarization method according to claim 1, wherein etching is performed at an ion incidence angle of 75°.