JPS6363112A - Production of thin film magnetic head - Google Patents

Abstract

PURPOSE:To suppress the generation of the reaction product by forming an insulator layer by a reactive ion etching method while a high-frequency electrode and substrate are held electrically insulated. CONSTITUTION:The conductive magnetic substrate 5 is imposed on the high-frequency electrode and the conductive magnetic substrate 5 and the high-frequency electrode are insulated from each other, then in this state the insulator layer 3 is etched by the reactive ion etching method using an etching device in which one high-frequency electrode is commonly used as a substrate 5a table in a process for exposing part of a magnetic material layer by etching the insulator layer 3. The generation of the reaction product on the magnetic material layer 1a essentially consisting of iron at the time of etching the insulator layer 3 is thereby suppressed even in the case of using the conductive magnetic substrate 5. Magnetical coupling is thus improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a thin film magnetic head, and is used, for example, in a magnetic disk device, a magnetic tape device, etc. that can perform magnetic recording.

(Prior Art) FIG. 3 shows the basic structure of a thin film magnetic head. In the figure, 5 is a substrate for forming a thin film magnetic head, 1 is an F
A magnetic core made of a ferromagnetic thin film whose main component is iron, such as e-A 1-3t alloy (Sendust). magnetic core 1
is composed of a lower core 1a and an upper core 1b, forming a magnetic circuit. Further, 2 is a lead made of a conductive thin film such as Cu or Ant, and a part of the lead is interposed between the lower core 1a and the upper core 1b. 3 is 5iOz *
Magnetic core 1 and lead 2 with an insulating layer such as 511N4.
It electrically insulates the The lower core 1a and the upper core 1b face each other at the gap portion A with an insulator N3 interposed therebetween, and are magnetically coupled at the back core portion B. 4 is a recording medium such as a magnetic tape or a magnetic disk.

In the thin film magnetic head with the above configuration, important factors related to head efficiency include the magnetic coupling state between the lower core 1a and the upper core 1b in the bank core section B (hereinafter referred to as the former), and the magnetic properties of the lower core 1a (hereinafter referred to as the former). (referred to as the latter).

Of these, for the former, lower core 1 of back core part B
It is required that there be no inclusions on the surface of a and that the surface roughness is small. If this condition is not satisfied, the magnetic resistance value increases in the back core portion B, making it difficult for magnetic flux to flow through the magnetic core 1, resulting in a decrease in recording and reproducing efficiency. This back core portion B is made of SiO□.

It is formed by partially etching the insulating layer 3 of Si, N, etc. to expose the surface of the lower core 1a. Etching methods include wet etching, ion beam etching, etc., but in order to miniaturize the head due to the high density such as multi-channel, which is a feature of thin film magnetic heads, etching of insulator N3 is recommended. It is essential to use reactive ion etching.

Furthermore, as a method for further improving the magnetic properties of the lower core 1a, 1) the lower core 1a is made thicker. ■
By using a substrate made of soft magnetic material, the lower core 1a
A similar effect can be obtained by thickening the . There are two possible methods. However, method (2) is difficult due to problems with its processing method, adhesion to the substrate, etc. On the other hand, conventionally, non-magnetic, non-conductive crystallized glass, etc., was used as the substrate, but in order to alleviate the difference in the coefficient of thermal expansion between the substrate and the magnetic layer, and to improve the head's wear resistance. time, for example M
The method (2) above using a soft magnetic material substrate known as an n-Zn ferrite substrate is advantageous.

(Problems to be Solved by the Invention) However, when using the method (2) using a soft magnetic material substrate, as shown in FIG. 4 (al), the soft magnetic material substrate 5
When etching the insulating layer 3 laminated on the magnetic layer (a) via the magnetic layer (lower core) la, if a commonly used cathode-coupled reactive dry etching device (see Figure 1) is used, the following will occur. A problem like this arises.

In other words, ■lower core 1 partially exposed after etching
A reaction product 6 [see FIG. 4(b)] is generated on the surface of the lower core 1a, which prevents the clean surface of the lower core 1a from being exposed. ■This reaction product 6 is chemically extremely inert, insoluble in water and common organic solvents (xylene, acetone, ethyl alcohol, etc.), and does not react with acids or alkalis, making it difficult to remove. .

For this reason, the upper core 1 remains unremoved without the reaction product 6 being removed.
There was a problem in that the head had to be fabricated by laminating the magnetic heads, making it impossible to manufacture a thin-film magnetic head with good head efficiency.

(Means for Solving the Problems) In the method for manufacturing a thin film magnetic head according to the present invention, a magnetic layer made of an iron-based alloy is formed on a conductive magnetic substrate, and an insulating layer is formed on the magnetic layer. A method for manufacturing a thin-film magnetic head having a structure in which a high frequency electrode is etched in a step of etching the insulating layer to expose a part of the magnetic layer using an etching device in which one high-frequency electrode also serves as a substrate table. ,
The conductive magnetic substrate is placed on the high frequency electrode, the conductive magnetic substrate and the high frequency electrode are insulated, and in this state the insulator layer is etched by a reactive ion etching method. .

(Function) The generation of reaction products is caused by the fact that the high-frequency electrode in the etching device and the magnetic layer, which is one of the elements constituting the thin-film magnetic head, are electrically connected through the substrate, and that the magnetic layer is This is due to the fact that the lower core is made of an iron-based alloy, so by forming an insulator layer using a reactive ion etching method while electrically insulating the high-frequency electrode and the substrate, Suppresses the generation of reaction products.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In this embodiment, as shown in FIG. 1, the etching apparatus is a cathode-coupled reactive dry etching apparatus in which the lower high-frequency electrode 12 also serves as a substrate table.

That is, in the figure, 11 is the upper high frequency electrode (anode), 12 is the lower high frequency electrode (cathode) mentioned above,
13 is an RF output section. In addition, Sendust, which has excellent magnetic properties, is used for the magnetic core 1 (lower core 1a + upper core lb), and Mn-Zn ferrite substrate 5 is used for the soft magnetic material substrate.
Use a respectively. Furthermore, as shown in FIG. 2 (al), a Teflon sheet or quartz plate 7 is placed between the Mn-Zn ferrite substrate 5a and the lower high-frequency electrode 12, and the sendust film (lower core) which is the layer to be etched is
Reactive ion etching was performed while electrically insulating la and the lower high-frequency electrode 12. Note that in FIG. 2, reference numeral 3 represents an insulator layer, and 8 represents a photoresist film.

The etching conditions were as follows: CF4 was used as the reactive gas, the gas pressure was 3.9 Pa, and the high frequency power was 175 W.

As a result, as shown in FIG. 2(b), no reaction products were generated. Similar results were also obtained when a copper plate was used as the substrate, a sendust film was laminated on the copper plate, and etching was performed under the same conditions as above.

Note that in order to compare the influence of the conductivity of the substrates, the following comparative experiment was conducted.

(Comparative Experiment Example 1) A glass substrate and a non-conductive crystallized glass were used as insulating substrates, and the above-mentioned M n -Z n ferrite substrate and copper plate were used as conductive substrates, and a sendust film was laminated on each substrate. Then, each of these was placed on the lower high frequency electrode 12, and reactive ion etching was performed. the result,
Reaction products were generated only on the conductive substrate, and no reaction products were observed on the insulating substrate.

(Comparative Experiment Example 2) Sendust on Mn-Zn ferrite substrate, (:
u.

A stack of Ti, Nb, and Ni, an iron plate (Fe>99.9%), an AJ plate, and a temporary St plate were each placed on the lower high-frequency electrode 12, and reactive ion etching was performed. As a result, in the case of using a Mn-Zn ferrite substrate, reaction products were generated only in the sendust film,
Similar reaction products were also generated on the iron plate.

From Comparative Experiment Examples 1 and 2 above, when the layer to be etched and the lower high-frequency electrode are electrically connected, reaction products are only generated when the layer to be etched is made of an alloy whose main component is iron. I understand.

(Effects of the Invention) As explained above, according to the method for manufacturing a thin film magnetic head according to the present invention, even when a conductive magnetic substrate is used, iron is the main component when etching the insulating layer. The generation of reaction products on the magnetic layer can be suppressed,
A thin film magnetic head with good magnetic coupling can be manufactured.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a reactive dry etching apparatus used in the manufacturing method of the present invention, FIG. 2 is a sectional view showing one step in manufacturing a thin film magnetic head by the manufacturing method of the present invention, and FIG. 3 is a cross-sectional view showing the basic structure of a thin-film magnetic head,
FIG. 4 is a cross-sectional view showing one step in manufacturing a thin film magnetic head by a conventional manufacturing method. 1... Magnetic core 1a... Lower core 1b...
・Upper core 2...Lead 3...Insulator N
4... Recording medium 5... Substrate 5a... Mn-Zn ferrite substrate 6... Reaction product 7... Teflon sheet or quartz plate 8... Photoresist film 11... Upper high frequency electrode 12... Lower high frequency electrode 13... RF output part A... Gap part B... Bank core part @7
Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1) A method for manufacturing a thin-film magnetic head having a structure in which a magnetic layer made of an iron-based alloy is formed on a conductive magnetic substrate, and an insulating layer is formed on the magnetic layer. , in the step of etching the insulating layer to expose a part of the magnetic layer, using an etching device in which one high-frequency electrode also serves as a substrate table, the conductive magnetic substrate is placed on the high-frequency electrode. At the same time, the conductive magnetic substrate and the high frequency electrode are insulated, and in this state, the insulator layer is etched by a reactive ion etching method.