JPH0520642A - Thin-film magnetic head - Google Patents

Abstract

PURPOSE:To improve the reliability of bonding without complicating the process for production of the thin-film magnetic head. CONSTITUTION:A 1st insulating layer 2, a 1st tight contact layer 3 consisting of a high melting metallic material, a winding conductor layer 4 consisting of Cu, and a 2nd tight contact layer 5 consisting of the high melting metallic material are successively formed on a substrate 1. After an insulating layer 8 is formed, a contact hole is worked in a part of the insulating layer 8. A diffusion preventive layer 5a which consists of the high melting metallic material and is in common use as the tight contact layer and an Al layer 6 consisting of Al as a bonding pad material are laminated on the exposed winding conductor layer 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head. More specifically, it relates to improvements in bonding pads.

[0002]

2. Description of the Related Art In a thin film magnetic head of an information recording / reproducing apparatus such as a magnetic tape apparatus, an electrode pad portion is, as shown in FIG.
A first insulating layer 2, a first adhesion layer 3 made of a refractory metal material, a winding conductor layer 4 made of Cu, and a second adhesion layer 5 made of a refractory metal material were sequentially laminated on a substrate 1. The second adhesive layer 5 is partially removed to expose the winding conductor layer 4, and the second insulating layer 8 is formed around these.

In the above structure, the coil (not shown) and the electrode pad 10 at the end of the coil are formed by the winding conductor layer 4
The coil is electrically connected to the outside by bonding the electrode pad 10 with the bonding wire 11.

[0004]

However, in the above-mentioned conventional structure, since the electrode pad 10 is made of Cu, an oxide film is formed on the surface thereof, so that wire bonding is difficult to perform. Further, it is easily peeled off even after wire bonding, resulting in deterioration of reliability.

Therefore, Ni and Au are deposited on the electrode pad 10.
It has been attempted to solve this problem by stacking and plating the electrodes with each other to prevent oxidation of the electrode pad 10. However, in order to carry out the above-mentioned stacking plating, a large amount of equipment investment is required. In addition, the manufacturing process is complicated. The present invention has been made to solve the above problems, can be manufactured in a simple process, wire bonding is easy to perform, thin film magnetic having a highly reliable bonding pad that does not easily peel off after wire bonding. It is intended to provide a head.

[0006]

According to the present invention, the first
A pattern of a winding conductor layer sandwiched by a first adhesive layer and a second adhesive layer is formed on a substrate on which an insulating layer is formed, and the pattern forming surface is covered with the second insulating layer to form a second insulating layer. A contact hole penetrating the layer and the second adhesive layer and reaching at least the winding conductor layer, and a bonding pad material is embedded in the contact hole via a diffusion prevention layer and on the contact hole and on the second insulating layer. Provided is a thin film magnetic head in which a bonding pad is formed so as to extend over the bonding pad and a bonding wire is connected to a predetermined position on the bonding pad material.

In the present invention, the pattern of the winding conductor layer sandwiched by the first adhesive layer and the second adhesive layer is formed on the substrate on which the first insulating layer is formed, and the pattern forming surface is provided with the pattern. Two insulating layers are covered. The substrate is used to form a thin film magnetic head, and is made of, for example, crystallized glass or ferrite.

The first insulating layer serves to insulate the substrate and the winding conductor layer from each other. For example, a silicon oxide film,
A silicon nitride film or the like is used. This film thickness is usually 1.
It is 0 to 3.0 μm. Further, this formation is performed, for example, by CVD.
It can be done by the law. The pattern of the winding conductor layer is for recording / reproducing at high frequency, and a first adhesion layer, a winding conductor layer, and a second adhesion layer are laminated in this order on the first insulating layer, This can be formed by patterning in a winding shape.

The winding conductor layer is preferably made of a metal having a low resistivity in order to improve recording efficiency, and can be made of, for example, Cu or Al. Cu is preferable because it has a resistivity lower than that of Al at about 0.7 and can reduce the film thickness and the coil width. The first adhesion layer is for adhering the first insulation layer and the winding conductor layer to each other, and can be made of, for example, Nb. This film thickness is usually 0.03
Is about 0.05 μm.

The second adhesion layer is for adhering the second adhesion layer and the winding conductor layer to each other, and can be similarly constructed. This film thickness is usually 0.1 to 0.4 μm. The second insulating layer is for insulating the patterns of the first and second adhesion layers and the winding conductor layer sandwiched by them, and covers them by using, for example, silicon oxide, silicon nitride or the like. Can be formed as follows.

In the present invention, the contact hole penetrating the second insulating layer and the second adhesion layer and reaching at least the winding conductor layer is opened. The contact hole is for forming a bonding pad that is electrically connected to the winding conductor layer, and is an opening that penetrates the second insulating layer and the second adhesion layer and reaches at least the winding conductor layer. And has a diameter of 10 to 100 μm and a depth of 1.0 to 3.0 μm.

In the present invention, the bonding pad material is embedded in the contact hole through the diffusion prevention layer, and the bonding pad is formed so as to extend over the contact hole and the second insulating layer. The diffusion prevention layer is for preventing the diffusion of each constituent atom while maintaining the electrical connection between the winding conductor layer and the bonding pad, and the winding conductor in the contact hole. For example, a layer of Nb or the like is laminated on the layer. This thickness is usually 0.2 to 0.3 μm.

The bonding pad is for disposing a bonding wire and electrically connecting the bonding wire to the winding conductor layer, and a bonding pad material is embedded in the diffusion preventing layer in the contact hole. It is formed to overhang the contact hole and the second insulating layer. As the bonding pad material, for example, Al or the like is used. The size of the bonding pad is usually 80 to 300μ in length.
m, width 80 to 120 μm, thickness (on the second insulating layer) 0.2
Is 0.5 μm.

In the present invention, a bonding wire is connected to a predetermined position on the bonding pad material to form a thin film magnetic head.

[0015]

The diffusion prevention layer made of Nb shields the winding conductor layer of the electrode pad from the external environment to prevent oxidation, and wire bonding is performed on the bonding pad material of the electrode pad, which facilitates bonding. become. Moreover, the diffusion prevention layer prevents diffusion of Cu constituting the winding conductor material into the bonding pad material. Further, even if a pinhole or the like of the diffusion prevention layer is generated and the diffusion occurs, the diffusion is stopped around the contact hole and the deterioration of the bonding does not occur, so that the reliability of the bonding improves.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 4, the thin film magnetic head of this embodiment includes a substrate 1 made of ferrite, crystallized glass, etc., a lower magnetic core 12 made of a ferromagnetic thin film formed so as to cover the substrate 1, and a lower magnetic core. Winding conductor layer 4 and winding conductor layer 4 made of Cu formed by patterning in a winding shape on 12
Electrode lead part 15 for connection to the outside made of a material similar to
Is formed, and is mainly composed of a step type upper magnetic core 14 provided in a position corresponding to the winding center of the winding conductor layer 4 and connected to the lower core 12. The winding conductor layer is made of an insulating layer such as a silicon oxide film or a silicon nitride film so as not to be short-circuited. The lower magnetic core 12 and the upper magnetic core are made of, for example, Fe-Al-Si.
Ferromagnetic materials containing Fe as a main component are used.

FIGS. 3A and 3B are a plan view and a side view showing a joint structure between the thin film magnetic head portion and the flexible printed circuit board portion. Referring to these drawings, first, the thin-film magnetic head unit includes a magnetic substrate 1, an element unit 16, and an electrode pad unit 15.
It is composed of a and 15b and a protection plate 17. An element portion is formed on the medium sliding surface side on a magnetic substrate made of ferrite or the like. Further, a large number of electrode lead portions 15a for connection to the outside are formed on the magnetic substrate 1 on the side of the connection portion so as to extend from the element portion 16. The tip of the electrode lead portion 15a is an electrode pad portion 15b having a wide width. A protective plate 17 made of ferrite, glass or the like is adhered to the surface of the element portion 16.
The medium sliding surface composed of the magnetic substrate 1, the element portion 16 and the protective plate 17 is processed into a shape having a predetermined curvature.

Next, the flexible printed circuit board 19 has a lead terminal 20, a base film 21 and a cover film 22.
It consists of On the surface of a base film 21 made of polyimide or the like, a large number of lead terminals 20 composed of an Au layer formed on a copper foil by a plating method are arranged. A cover film 22 is adhered to the surface of the lead terminal 20 so as to expose the end portion of the lead terminal 20.

The thin film magnetic head portion 18 and the flexible printed board 19 are adhered to the support plate 23 made of glass, metal or the like in a highly accurately positioned state. Support plate 2
Electrode pad portion 1 of thin film magnetic head portion 18 adhered to 3
5b and the lead terminal 20 exposed from one end of the flexible printed board 19 are electrically connected by a wire 24 made of Au or Al.

Details of the electrode pad portion 15b, which is made of the same material as the winding body layer 4 and has a wide tip end portion of the electrode lead portion 15a for external connection, are shown in FIGS.
The explanation is based on the following. In the thin film magnetic head of this embodiment, as shown in FIG. 1, the electrode pad portion has a first insulating layer 2 on a substrate 1, a first adhesion layer 3 made of a refractory metal material, and a winding made of Cu. The conductor layer 4 and the second adhesion layer 5 made of a refractory metal material are sequentially laminated, and after the insulating layer 8 is further formed, the insulating layer 8 is formed.
A diffusion preventing layer 5a made of a refractory metal material and also serving as an adhesion layer, and an Al layer 6 made of Al as a bonding pad material were further laminated on the exposed winding conductor layer 4 by performing contact hole processing on a part of It is configured.

In the above structure, the coil (not shown) and the electrode pad portion 10 at the end of the coil are formed by the winding conductor layer 4, and the electrode pad portion 10 has a contact hole in a part thereof. The coil is electrically connected to the outside by wire-bonding the Al layer 6 laminated on the diffusion prevention layer 5a provided via the insulating layer 8.

According to the above configuration, the electrode pad portion 10
Is not oxidized because it is insulated from the outside air by the diffusion prevention layer 5a and the Al layer 6. As a result, the deterioration of the bonding property due to the oxidation of the electrode pad portion 10 is eliminated.
Moreover, the diffusion prevention layer 5a prevents the Cu of the electrode pad 10 from
It is also prevented from diffusing into the I-layer 6 and deteriorating the bonding property. Further, even if a pinhole or the like is generated in the diffusion prevention layer 5a and the diffusion occurs, the diffusion stops around the contact hole and the Al layer 6 at the bonding portion of the bonding wire 11 is not attacked, so that the deterioration of the bonding occurs. Absent. Hereinafter, a method of manufacturing the electrode pad portion of the thin film magnetic head will be described with reference to FIGS. 1 and 2A to 2D.

As shown in FIG. 2A, Si is formed on the substrate 1.
The first insulating layer 2 made of an insulating material such as O ₂ is formed by P-CVD to a thickness of about 2.5 μm. Next, a first adhesion layer 3 made of a refractory metal material such as Ti or Nb is formed on the first insulating layer 2 by an EB vapor deposition method so as to have a film thickness of 500Å, and then a winding made of Cu is formed. The conductor layer 4 is formed to have a film thickness of 1.5 to 2.0 μm, and the second adhesion layer made of a refractory metal material such as Nb is also made to have a film thickness of 1000 to 1500 Å by the same EB vapor deposition method. To form. Then, a photoresist 7 having a predetermined pattern of bonding pads is formed on the second adhesion layer 5.
To form.

Next, by ion schilling using Ar gas, leaving the portion covered with the photoresist 7 first,
Etching is performed until the insulating layer 2 is exposed, and the photoresist is removed (FIG. 2B). Then, Figure 2 (C)
As shown in FIG. 3, the second insulating layer 8 made of an insulator such as SiO ₂ is formed to have a film thickness of about 1.0 μm by the P-CVD method so as to cover the first insulating layer 2 to the second adhesive layer 5. After that, a photoresist 9 is formed on the second insulating layer 8 so that the contact hole is located at the end of the second adhesive layer 5, and patterning is performed.

Next, the second insulating layer 8 and the second adhesion layer 5 are etched by ion schilling, leaving the portion covered with the photoresist 9, to expose the electrode pad portion 10 composed of the winding conductor layer 4. Let Then, the photoresist 9 is removed (FIG. 2D). Then, as shown in FIG.
A diffusion prevention layer 5a made of a high melting point metal material such as Nb and also serving as an adhesion layer is formed in the contact hole portion on the electrode pad portion 10 by EB vapor deposition so as to have a film thickness of about 3000 Å. Then, an Al layer 6 made of is formed on the contact hole portion and the second insulating layer 8 by EB vapor deposition so as to have a film thickness of 3000 to 5000Å.

As described above, according to the manufacturing method of this embodiment, the electrode pad portion exposed by the contact hole is manufactured by the same conventional manufacturing process, and then the same manufacturing equipment is used to perform the EB evaporation method. Electrode pad section 10
Since the diffusion prevention layer 5a and the Al layer 6 are formed on the upper side, there is no need to make an expensive capital investment, and moreover, two steps are added without changing the conventional manufacturing steps, and the bonding property and the reliability are improved. The excellent electrode pad portion of the thin film magnetic head can be manufactured.

[0027]

As described above, the thin film magnetic head of the present invention has the electrode pad portion in which the diffusion preventing layer and the bonding material are laminated after the insulating layer having the contact holes is formed on the winding conductor layer. Therefore, the winding conductor layer of the electrode pad portion is shielded from the external environment to prevent oxidation, and wire bonding is performed on the bonding pad material of the electrode pad portion, which facilitates the bonding.

Moreover, the diffusion preventing layer prevents Cu, which is the winding conductor material, from diffusing into the bonding pad material. Further, even if a pinhole or the like is generated in the diffusion prevention layer and the diffusion occurs, the diffusion is stopped around the contact hole and the deterioration of the bonding does not occur, so that the reliability of the bonding is significantly improved. Further, the thin film magnetic head of the present invention has an effect that it does not require introduction of new equipment and is manufactured without complicating the process.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a thin film magnetic head manufactured in an example of the present invention.

FIG. 2 is also an explanatory diagram of a manufacturing process of the thin film magnetic head.

FIG. 3 is an explanatory diagram of a manufacturing process of the thin film magnetic head, similarly.

FIG. 4 is an explanatory diagram of a manufacturing process of the thin film magnetic head, similarly.

FIG. 5 is an explanatory diagram of a conventional thin film magnetic head.

[Explanation of symbols]

 1 Substrate 2 First Insulation Layer 3 First Adhesion Layer 4 Winding Conductor Layer 5 Second Adhesion Layer 5a Diffusion Prevention Layer 6 Al Layer (Bonding Pad Material) 8 Second Insulation Layer 10 Electrode Pad

Claims (1)

Claim: What is claimed is: 1. A first insulating layer is formed on a substrate, and the first insulating layer is formed on the substrate.
A pattern of the winding conductor layer sandwiched by the adhesive layer and the second adhesive layer is formed, the pattern forming surface is covered with the second insulating layer, and penetrates the second insulating layer and the second adhesive layer to form at least the winding. A contact hole reaching the conductor layer is opened, a bonding pad material is embedded in the contact hole via a diffusion prevention layer, and a bonding pad is formed so as to extend over the contact hole and the second insulating layer.
A thin film magnetic head having a bonding wire connected to a predetermined position on a bonding pad material.