JPH0266712A - Thin film magnetic head and its manufacture - Google Patents

Abstract

PURPOSE:To equally keep the characteristic of a magnetic layer and to prevent the warp and crack of a substrate by impressing a direct current bias voltage through a conductive metallic film to cover the whole surface of the substrate, and controlling the stress between a lower part magnetic layer and a substrate. CONSTITUTION:A metallic film 2 is formed on a substrate 1 and an upper laminating construction from a lower part magnetic layer 3 is formed on the film 2. When a direct current bias voltage is impressed through a jig by a base 10 and a flange 11, it is brought into contact with the flange 11 and both are electrically coupled. Thereafter, together with a jig, the substrate 1 is fitted to a sputter device and a sendust film which goes to the layer 3 is sputtered. At such a time, while a bias voltage is impressed through a jig and the film 2 to the substrate 1, the film is formed. Thereafter, on the layer 3, a coil due to conductive layers 4a and 4b is formed, after the insulating film is formed, a magnetic contact hole 5 and a magnetic gap 6 are provided and continuously, an upper part magnetic layer 7 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a thin film magnetic head, particularly a thin film magnetic head formed by forming upper and lower magnetic layers constituting a magnetic path and a conductive layer constituting a coil as thin films on a substrate. It is related to the head.

[Prior Art] Thin-film magnetic heads have the advantage of being suitable for mass production and being easy to reduce in size and weight because all of the constituent members such as magnetic paths and coils are formed by the thin-film forming method.

The structure of a conventional thin film magnetic head is shown in FIG.

In FIG. 5, reference numeral 1 denotes a substrate made of glass or the like, and an upper structure as shown is constructed on this substrate using a thin film deposition method.

First, sendust (Fe-All-Si
A lower magnetic layer 3 made of 5i02 or the like is formed to a thickness of 5 to 15 .mu.m, and then conductive layers 4a and 4b, which become coils, are formed with an insulating layer 5i02 or the like interposed therebetween.

The coil portion of the conductive layer 4a is shaped into a spiral pattern by a method such as etching, and the coil portion of the conductive layer 4b is shaped into a spiral pattern.
The central end of the spiral pattern of the conductive layer 4a is led out to the rear of the head. Except for the central joint portion of the conductive layers 4a, 4b, the overlapping portions are electrically isolated by at least the insulating layer.

Furthermore, an insulating layer (not shown) made of SiO2 is formed as a conductive layer 4.
a and 4b, and a magnetic contact hole 5 for magnetically coupling the upper magnetic layer 7 and the lower magnetic layer 3 is formed in this insulating layer. Furthermore, at the same time, a magnetic gap 6 is formed at the position where the upper magnetic layer 7 is formed.

After that, the lower magnetic layer 3 is connected to the lower magnetic layer 3 through the magnetic contact hole 5.
is coupled to the lower magnetic layer 3 via the magnetic gap 6.
The upper magnetic layer 7 facing the wafer is formed, and then a protective layer (not shown) is formed on the above laminated structure to complete the wafer process. FIG. 5 shows a structure in which Herad chips for two channels are formed on the substrate 1.

[Problems to be Solved by the Invention] The reason why a metal material such as sendust is used as the upper magnetic layer 7 or the lower magnetic layer 3 is to correspond to a magnetic recording medium with a high coercive force. When the sendust film as the lower magnetic layer 3 is formed using an RF magnetron sputtering device, the thermal expansion coefficient of the sendust is larger than that of the substrate 1, so tensile or compressive stress is generated between the two. . This tendency becomes particularly noticeable when the film thickness becomes thick or when the film is formed while maintaining the substrate temperature at about 300°C. This tensile stress may cause warping or cracking of the substrate, which poses a problem of extremely low yield in the head manufacturing process.

A bias sputtering method is known as one of the methods for controlling the warpage of the substrate 1. This is a method of forming a film while applying a DC bias voltage to the substrate 1, and it is possible to control the stress generated in the film by the so-called piling effect.

According to this method, film formation can be performed while controlling compressive stress and tensile stress, so that warping and cracking of the substrate 1 can be prevented.

However, although a dielectric material such as glass is used as the substrate 1, with such a material, it is not possible to apply the desired bias voltage at the initial stage of film formation, or the substrate may be damaged due to uneven bias application due to poor contact during film formation. There was a problem in that it became difficult to control the warpage. For the same reason, changes in the composition of the magnetic material caused by fluctuations in the bias current during film formation can cause problems with the conversion characteristics of the head and uneven surface roughness of the head chip. there were.

The object of the present invention is to solve the above problems, and when forming a film on a head substrate, apply a uniform DC bias voltage at all times throughout the film forming process, control stress between materials as desired, and prevent warping of the substrate. This is to prevent cracking and cracking.

[Means for Solving the Problems] In order to solve the above problems, the present invention uses a thin film formed by forming upper and lower magnetic layers forming a magnetic path and a conductive layer forming a coil on a substrate. In a magnetic head and a manufacturing method thereof, prior to sputtering a lower magnetic layer on the substrate, a conductive metal film is first formed on the substrate so as to cover almost the entire surface of the substrate, and in the step of forming the lower magnetic layer, adopted a configuration in which the stress between the lower magnetic layer and the substrate is controlled while applying a DC bias voltage through the conductive metal film.

[Function] According to the above configuration, a DC bias voltage can be uniformly applied during the film formation of the lower magnetic layer through the conductive film provided on almost the entire surface of the substrate, and the direct current bias voltage can be uniformly applied between the lower magnetic layer and the substrate. The stress can be adjusted reliably.

Further, the characteristics of the magnetic layer can be kept uniform by applying a uniform DC bias voltage.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIG. 1 shows the structure of a thin film magnetic head employing the present invention. The overall structure of the thin film magnetic head shown in FIG. 1 is almost the same as the conventional structure shown in FIG. The difference between FIG. 1 and FIG. 5 is that there is a conductive metal I between the substrate 1 and the lower magnetic layer 3.
Except for the provision of I@2, the other structures, ie, the upper structure above the lower magnetic layer 3 and the manufacturing process thereof, are exactly the same as in FIG.

Next, the manufacturing process of the thin film magnetic head shown in FIG. 1 will be explained.

First, metal II! form 2. This metal film is formed by vapor deposition or sputtering to a thickness of 50 to 200 nm.
Deposited to a certain extent. This metal II! 2 is formed on the entire surface of the substrate 1, but since the film thickness is thin, film peeling and stress do not pose any particular problems.

Subsequently, a laminated structure starting from the lower magnetic layer 3 is formed on this metal film 2 by the same process as in the conventional method. At this time, as shown in FIGS. 2 and 3, the substrate 1 is It is fixed in a jig for sputtering equipment with the side facing up.

The substrate 1 has a disk shape as in the conventional case, and the jig includes a base 10 and a ring-shaped flange 11 that is connected to the base 10 by screwing or the like.

Since a DC bias voltage is applied through the jig made up of the base 10 and the flange 11, these materials need to be electrically conductive. Naturally, when installing board 1,
The metal film 2 on the surface of the flange 11 contacts the flange 11 as shown in the cross section of FIG. 3, and the two are electrically coupled.

After that, attach the substrate 1 together with the jig to a sputtering device, and
A sendust film, which will become the lower magnetic layer 3 in FIG. 1, is sputtered to a thickness of 5 to 15 μm using an f-magnetron type sputtering device. At this time, film formation is performed while applying a bias voltage (DC) of -100 to 100 volts to the substrate 1 via the jig and the metal film 2.

The conditions for this bias voltage depend on the film formation conditions, such as the substrate material,
FIG. 4 shows an example of the relationship between the DC bias voltage and the amount of warping of the substrate 1 caused by the bias voltage, although it varies depending on the gas pressure, substrate temperature, distance between the substrate and the target, etc.

Therefore, by controlling the DC bias voltage during film formation based on the characteristics shown in FIG. 4, it is possible to reduce warping of the substrate or prevent cracking of the substrate. Note that the term "film surface" in FIG. 4 indicates the surface on which the metal film 2 in FIGS. 2 and 3 is provided.

The subsequent manufacturing process is exactly the same as the conventional one, in which a coil is formed by conductive layers 4a and 4b made of Cu, A, and Il on the lower magnetic layer 3, an insulating layer is formed, and then a magnetic contact hole 5 and a magnetic contact hole 5 are formed. A gap 6 is provided, and then an upper magnetic layer 7 made of sendust or the like is formed so as to be connected to the lower magnetic layer 3 via the magnetic contact hole 5 and to face each other with the magnetic gap 6 in between. Furthermore, the wafer process is completed by covering the film surface with a protective layer. Next, a single thin film magnetic head is completed through a process such as cutting the head chip.

According to the above embodiment, when forming a film on the substrate 1,
First, the metal film 2 is provided on the upper surface of the substrate 1, and the lower magnetic layer 3 is deposited by sputtering while applying a DC bias through the metal film 2, so that the stress between the lower magnetic layer 3 and the substrate 1 can be adjusted to the desired level. It is possible to achieve a film forming process without substrate warping or substrate cracking, and therefore the yield in manufacturing thin film magnetic heads can be significantly improved.

Note that a metal film 2 for applying a DC bias provided on the substrate 1
The above effect can be achieved by using a conductive material as the material of the metal film 2. However, if Cr is used as the metal film 2, the above-mentioned DC bias can be applied, and the adhesion strength between the substrate 1 and the lower magnetic layer 3 can be improved. It was found that it has the effect of increasing

Therefore, by using Cr as the metal film 2, the strength of the thin film magnetic head can be increased and the reliability of the thin film magnetic head can be improved.

[Effects of the Invention] As is clear from the above, the present invention provides a thin film magnetic head in which upper and lower magnetic layers constituting a magnetic path and a conductive layer constituting a coil are formed as thin films on a substrate, and the manufacture thereof. In the method, before sputtering a lower magnetic layer on the substrate, a conductive metal film is first formed on the substrate so as to cover almost the entire surface of the substrate, and in the step of forming the lower magnetic layer, the conductive metal film is This structure controls the stress between the lower magnetic layer and the substrate while applying a DC bias voltage through the conductive film provided on almost the entire surface of the substrate. The DC bias voltage can be applied uniformly, and the stress between the lower magnetic layer and the substrate can be reliably adjusted, and the characteristics of the magnetic layer can be kept uniform by applying a uniform DC bias, so the warping of the substrate can be prevented. It is possible to provide a thin-film magnetic head and a method for manufacturing the same, which can prevent cracking and cracking and have a high yield and excellent magnetic properties.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating a thin film magnetic head and its manufacturing method according to the present invention, FIG. 2 is an exploded perspective view showing how the substrate of FIG. 1 is attached to a jig, and FIG. 3 is a perspective view of the substrate jig. FIG. 4 is an explanatory diagram showing the relationship between the DC bias voltage and the amount of warpage of the substrate, and FIG. 5 is a perspective view showing the structure of a conventional thin film magnetic head. DESCRIPTION OF SYMBOLS 1... Substrate 2... Metal film 3... Lower magnetic layer 4a, 4b... Conductive layer 5... Magnetic contact hole 6... Magnetic gap 7... Upper magnetic layer 10...
・Base 11...Flange [Tayama No. 1 (・100 Electric

Claims (1)

[Claims] 1) A thin film magnetic head in which upper and lower magnetic layers forming a magnetic path and a conductive layer forming a coil are formed as thin films on a substrate, the lower magnetic layer being formed on the substrate. A conductive metal film is formed between the substrate and the substrate so as to cover almost the entire surface of the substrate, and when a lower magnetic layer is formed on the substrate by sputtering, a DC bias voltage is applied through the conductive metal film. A thin film magnetic head characterized by controlling stress between a lower magnetic layer and a substrate. 2) In a method for manufacturing a thin film magnetic head in which upper and lower magnetic layers constituting a magnetic path and a conductive layer constituting a coil are formed as thin films on a substrate, a step of forming a lower magnetic layer on the substrate by sputtering. Prior to this, a step of forming a conductive metal film on the substrate so as to cover almost the entire surface of the substrate is provided, and in the step of forming the lower magnetic layer, a DC bias voltage is applied through the conductive metal film while A method for manufacturing a thin-film magnetic head characterized by controlling stress between a magnetic layer and a substrate.