JPH05120633A - Production of thin-film magnetic head - Google Patents

Abstract

PURPOSE:To improve the magnetic characteristics of the thin-film magnetic head by constituting this head in such a manner that a heat treatment can be executed without generating internal stresses after the formation of core layers. CONSTITUTION:Insulating layers 2 to 7 are formed by converting a material essentially consisting of TiO2 to an amorphous material. For example, the substrate 1 side is forcibly cooled to <=200 deg.C and the material essentially consisting of the TiO2 is released by high-speed sputtering at >=50Angstrom /min to form the layers. The heat treatment for imparting magnetic anisotropy after the formation of respective cores 8, 9a, 9b, 10 is enabled by the high heat resistance of the insulating layers 2 to 7. Since this material is nearly equal to the coefft. of thermal expansion of the material for the substrate 1, etc., the deterioration in the magnetic characteristics arising from the generation of stresses at the time of the heat treatment is prevented. Further, the perfect insulation by a uniform coating and the working with high accuracy at a high rate by dry etching are attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a thin film magnetic head used in a magnetic recording / reproducing apparatus and the like, and by improving the constituent material of the insulating layer, the magnetic characteristics of the thin film magnetic head are improved and The present invention relates to a method that enables highly accurate processing.

[0002]

2. Description of the Related Art Generally, in a thin film magnetic head of a magnetic recording / reproducing apparatus or the like, an upper core and a lower core are joined by one intermediate core, and one surface of the other intermediate core is joined by an upper core or a lower core. Has a basic structure in which a magnetic gap is formed without joining the other surfaces, and a spiral coil pattern is formed around an intermediate core joined to the upper core and the lower core.

Further, in manufacturing the above-mentioned thin film magnetic head, a process of forming a core and a coil pattern while forming an insulating layer on a substrate by making full use of a vacuum thin film forming technique, photolithography and etching method is adopted. By the process, a structure in which a core and a coil pattern are embedded in an insulating layer is obtained.

Conventionally, the insulating layer of the thin-film magnetic head is made of an organic insulating material excellent in electrical / magnetic insulating property or
Inorganic materials such as SiO ₂ and Al ₂ O ₃ are used, and magnetic materials such as permalloy, amorphous and iron nitride are used for the core.

[0005]

By the way, the core described above is subjected to a heat treatment at 300 ° C. to 600 ° C. after forming its layer to impart the required magnetic anisotropy to the magnetic characteristics of the magnetic circuit. The heat treatment process is often indispensable for improving the performance of the thin film head.

However, when an organic insulating material is used for the insulating layer, it is impossible to perform the above heat treatment because its heat resistant temperature is 300 ° C. or lower, and it should be used as it is in a state where magnetic properties are poor. I have no choice.

On the other hand, the insulating layer has excellent heat resistance such as SiO ₂ or Al ₂ O.
_When an inorganic material such as ₃ is used, the above heat treatment can be performed, but conversely, the following problem occurs. First, since SiO ₂ has an extremely small coefficient of thermal expansion and is greatly different from the coefficient of thermal expansion of the material of the substrate or core, internal stress is generated on the core side during the heat treatment stage, resulting in deterioration of the magnetic characteristics of the magnetic circuit. There is a drawback.

On the other hand, Al ₂ O ₃ has a coefficient of thermal expansion substantially equal to that of the material of the substrate or core, and does not cause a problem regarding stress during heat treatment. Also, Al ₂ O ₃
Since is also excellent in abrasion resistance, it can be said that it is a material suitable for a magnetic head. However, Al ₂ O ₃ has a characteristic that dry etching is difficult, and high-precision processing by dry etching is indispensable in the manufacturing process of the thin film magnetic head, which causes a disadvantage in manufacturing. ..

Further, when Al ₂ O ₃ is used, a problem is likely to occur at the stage of layer formation. That is, as shown in FIG. 14, the insulating layer 51 includes a substrate 52 and a core (or coil) 53 previously formed by a method such as vapor deposition, sputtering or CVD.
It is ideal that evenly coated formed on the, Al ₂ O
_{If 3} is used, as shown in FIG. 15, the core (or coil) 5
Crystals of Al ₂ O ₃ may be abnormally generated at the stepped portion 53a of 3 and the insulating coating at the stepped portion 53a becomes incomplete, and the insulating layer 5
It is not uncommon for the core and coil layers formed through 1 to short-circuit.

As described above, there are various problems in the material of the insulating layer which has been conventionally used in the thin film magnetic head.
A high-performance magnetic head could not be manufactured with high yield. Therefore, the present invention was created for the purpose of providing a thin film magnetic head which does not cause the above-mentioned problems by proposing a novel insulating layer and a method of forming the same.

[0011]

According to the present invention, in a method of manufacturing a thin film magnetic head in which a core and a coil pattern are embedded in an insulating layer, an insulating layer is formed by amorphizing a material containing TiO ₂ as a main component. And a method for manufacturing a thin film magnetic head.

When a material containing 30% or less of oxide in mol% with respect to TiO ₂ is used, the heat resistance of the insulating layer can be further improved.

In particular, 5% to 30% of Si in mol% relative to TiO ₂ .
When a material containing O2 is used, heat resistance can be dramatically improved without lowering the etching rate.

[0014]

[Function] Al ₂ O ₃ , TiO ₂ , α-, which has excellent heat resistance and whose coefficient of thermal expansion is close to that of the substrate or core (magnetic material)
Fe ₂ O ₃ and ZrO ₂ exist. All of these materials are difficult to process by wet etching, but dry etching with CF ₄ is possible, and as shown in Table 1 below, TiO ₂ is much higher than other materials. It has an etching rate.

[0015]

[Table 1]

Therefore, according to the method of manufacturing the thin film magnetic head of the present invention, the magnetic characteristics are not deteriorated due to the stress even when the heat treatment is performed at the manufacturing stage, and the processing can be performed by the rapid etching. Furthermore, since highly accurate processing by dry etching can be realized, a high-performance thin film magnetic head with a high packaging density can be obtained.

Further, in the present invention, since TiO ₂ is amorphized to form the insulating layer, abnormal crystal growth unlike the case of conventional Al ₂ O ₃ is eliminated, and a uniform insulating coating is always provided even in the step portion. Since this can be realized, short-circuiting of the core and coil pattern can be prevented. By the way, TiO ₂ is crystalline in a normal state and does not easily become amorphous like SiO ₂ . However, for example, using a device with a high layer formation rate such as a magnetron sputtering device, 50 Å /
A layer can be formed in an amorphous state by forming the layer for more than a minute and forcibly cooling the substrate side to keep the temperature at 200 ° C. or lower.

From the viewpoint of heat resistance, it has higher heat resistance than organic insulating materials, but the crystallization temperature of 100% pure TiO ₂ is about 320 ° C., and heat treatment at temperatures higher than that. Problems arise when applying. However, TiO ₂ to ZrO ₂ ,
By adding other oxides such as α-Fe ₂ O ₃ , Al ₂ O ₃ and SiO ₂ , the crystallization temperature can be increased, and heat treatment at high temperature for improving magnetic properties can be performed. However, an insulating layer having sufficient heat resistance can be formed.

Table 2 below shows the crystallization temperature obtained experimentally when each additive is added to TiO ₂ , for example, Si
In the case of adding O ₂ in 20% by mol%, the crystallization temperature can be increased to 500 ° C. or higher.

[0020]

[Table 2]

Further, as described above, when SiO ₂ is added, the coefficient of thermal expansion thereof is slightly smaller than that of TiO ₂ having a purity of 100%, but at about 80/10 ⁷ , there is almost no problem in practical use, and dry The etching rate of etching is 100% pure TiO ₂
Is equivalent to. In Table 2, the addition amount is 20
%, The heat resistance is improved by adding additives up to 30% as long as it does not cause the problem of deterioration of magnetic properties due to the difference in coefficient of thermal expansion from the substrate side or core side. Is possible.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a cross-sectional view of a main part of a thin film magnetic head of this embodiment, and FIG. 2 shows a planar relationship between a core, a coil pattern and a lead wire pattern. Note that FIG. 1 corresponds to a cross section taken along the line XX in FIG. 2, and the final product as a thin film magnetic head is taken along the line CC (two-dot chain line) in each drawing.

In both of the above figures, 1 is a substrate, 2, 3, 4, 5,
6, 7 is an insulating layer, 8 is a lower core, 9a and 9b are intermediate cores, 10 is an upper core, 11 is a coil pattern, 12 is a lead wire pattern,
13 is a protective film. And structurally, cores 8, 9a, 9b,
10, a coil pattern 11 and a lead wire pattern 12 are embedded in a layered manner inside an insulating layer. As shown in FIG. 2, the coil pattern 11 is spirally extended around the intermediate core 9b. There is. Further, the gap between the intermediate core 9a and the lower core 8 in which the insulating layer region 4a in FIG. 1 is interposed serves as a magnetic gap. In this embodiment, the substrate 1 is made of alumina titanium carbide, the cores 8, 9a, 9b, 10 are made of soft magnetic material such as permalloy and amorphous magnetic material, and each insulating layer is made of TiO ₂
A material in which SiO ₂ is added as a main component in an amount of 20% by mol% and formed into an amorphous layer is used. In the following, the above-mentioned insulating layer material is simply referred to as “the insulating material of the subject”.
Say.

Next, a method of manufacturing the thin film magnetic head according to the present embodiment will be sequentially described with reference to FIGS. [Step 1 (see FIG. 3)] First, in a state where the substrate 1 is forcibly cooled to 200 ° C. or lower, the insulating material is discharged onto the surface of the substrate 1 using a magnetron sputtering device, and the rate is 50 Å / min or more. An insulating layer 2 of 1 μm to 20 μm is formed (FIG. 3
reference). In this step, the present insulating material is deposited on the substrate 1 in an amorphous state, and the insulating layer 2 is formed as an amorphous layer.

[Step 2 (see FIG. 4)] A layer of a soft magnetic material such as permalloy, amorphous magnetic material, sendust, or iron nitride is formed on the insulating layer 2 by sputtering or vapor deposition, and the layer is formed. Is etched to form a core layer, leaving only a portion corresponding to the lower core 8. At this stage, heat treatment at 300 ° C. to 500 ° C. is applied to impart magnetic anisotropy in the layer direction to the lower core 8.

[Step 3 (see FIG. 5)] By the same method as in step 1, an amorphous layer thicker than the lower core 8 is formed on the insulating layer 2, and the surface of the layer is polished to make it thicker than the lower core 8. The formed portion is removed and flattened. As a result, the insulating layer 3 is formed.

[Step 4 (see FIG. 6)] In the same manner as in Step 1, an amorphous layer of 0.1 μm to 1 μm is formed on the flattened surface, and the amorphous layer is formed by dry etching using CF _4. The formation region of the intermediate core 9b described later in 1 is removed. As a result, the insulating layer 4 is formed.

[Step 5 (see FIG. 7)] In the same manner as in step 2, after forming a layer having a soft magnetic material amount thicker than the thickness of the intermediate core 9b described later, the intermediate core 9 is etched and polished.
Form a, 9b. At this stage, heat treatment at 300 ° C. to 500 ° C. is applied to impart magnetic anisotropy to the intermediate cores 9a and 9b in a direction perpendicular to the layers.

[Step 6 (see FIG. 8)] The intermediate core 9 is formed on the surface formed by the insulating layer 4 and the intermediate cores 9a and 9b in the same manner as in the step 1.
An amorphous layer thicker than a and 9b is formed, and the surface of the layer is polished to remove the portion thicker than the intermediate cores 9a and 9b and planarize. As a result, the insulating layer 5 is formed.

[Step 7 (refer to FIG. 9)] The coil pattern 1 of FIG. 2 is formed on the insulating layer 5 by dry etching using CF ₄ .
A spiral groove corresponding to the arrangement area of 1 is formed, and Cu is embedded in the groove by embedded coil etching to form a coil pattern 11. The coil pattern 11 is formed around the intermediate core 9b.

[Step 8 (see FIG. 10)] In the same manner as in step 1, the insulating layer 5, the intermediate cores 9a and 9b, and the coil pattern are formed.
An amorphous layer of 0.5 μm to 1 μm is formed on the surface formed by 11, and the region corresponding to the intermediate cores 9a and 9b of the amorphous layer is removed by dry etching using CF4. As a result, the insulating layer 6 is formed.

[Step 9 (see FIG. 11)] On the surface formed by the insulating layer 6 and the intermediate cores 9a, 9b, a soft magnetic material such as permalloy, amorphous magnetic material, sendust, or iron nitride is formed by sputtering or vapor deposition. Is formed and the layer is etched to form a core layer, leaving only a portion corresponding to the upper core 10. Also, at this stage 300
By subjecting the upper core 10 to heat treatment at a temperature of ℃ to 500 ℃, magnetic anisotropy in the layer direction is given to the upper core 10.

[Step 10 (see FIG. 12)] By the same method as in Step 1, an amorphous layer thicker than the thickness of the upper core 10 is formed on the surface formed by the insulating layer 6 and the intermediate core 10, and the layer The surface is polished to remove the portion formed thicker than the upper core 10 and flatten it. As a result, the insulating layer 7 is formed.

[Step 11 (see FIG. 13)] A coil pattern 11 is formed on the insulating layer 7 by dry etching using CF ₄ .
A through hole is formed which leads to the innermost side, and the through hole is filled with Cu, and the lead wire pattern 12 is formed on the insulating layer 7 by connecting to the filled Cu.

[Step 12 (see FIG. 1)] By applying a protective film 13 on the insulating layer 7 and the lead wire pattern 12, the structure shown in FIG. 1 is obtained. Regarding the formation of the protective film 13, an insulating layer may be formed by the same method as in step 1. Finally, the thin film magnetic head as a product is obtained by cutting along the line CC in FIG. 1 and polishing the cut surface.

As described above, the insulating layers 2, 3, 4, 5, 6, 7 of the thin film magnetic head according to the present embodiment contain SiO ₂ with TiO ₂ as a main component.
It is made to be a layer by amorphizing the material with 20% added. Therefore, the insulating layers 2, 3, 4, 5, 6, 7 have a high crystallization temperature of 500 ° C. as shown in Table 2, and the heat treatment for improving the magnetic characteristics in the above steps 2, 5, 9 It has sufficient heat resistance. In addition, since its coefficient of thermal expansion is also substantially the same as that of the substrate 1 and the cores 8, 9a, 9b, and 10, internal stress does not occur in the cores 8, 9a, 9b, and 10 in the heat treatment process,
It is possible to embed the cores 8, 9a, 9b, 10 without deteriorating the magnetic characteristics. Furthermore, the insulating layers 2, 3, 4, 5, 6,
As shown in Table 1, 7 has an extremely high etching rate with CF ₄ , and therefore high-accuracy and rapid manufacturing by dry etching is possible.

[0036]

EFFECTS OF THE INVENTION The present invention having the above-mentioned constitution has the following effects. The invention of claim 1 is
Since the insulating layer is composed of an amorphous layer containing TiO ₂ as a main component, it is possible to perform a heat treatment for improving the magnetic characteristics after forming the core layer, and realize a thin film magnetic head with less recording / reproducing loss. That is, since the amorphous layer has excellent heat resistance and its coefficient of thermal expansion is almost the same as that of the material of the substrate and the core, heat treatment should be performed without generating internal stress in the core after forming the layer. Therefore, it becomes possible to construct a highly efficient magnetic circuit. Further, when forming the insulating layer on the surface on which the core or the coil pattern is formed, there is no abnormal growth of crystals at the step portion as in the case of using Al ₂ O _3, and it is always uniform. Since the insulating coating is possible, it is possible to prevent a decrease in yield due to defective insulation between the core and the coil pattern. Further, from the viewpoint of the manufacturing process, the insulating layer can be dry-etched at a high etching rate, and a highly accurate thin film magnetic head can be manufactured in an efficient process. According to the invention of claim 2, the heat resistance of the insulating layer is improved, and the heat treatment temperature can be selected in a wider range. According to the invention of claim 3, the heat resistance of the insulating layer is remarkably enhanced without lowering the etching rate of the insulating layer to facilitate the heat treatment of the core.
Achieve efficiency in the manufacturing process.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a thin film magnetic head manufactured by a method of manufacturing a thin film magnetic head according to the present invention.

FIG. 2 is a diagram showing a planar relationship among a core, a coil pattern, and a lead wire pattern.

FIG. 3 is a main-portion cross-sectional view showing the manufacturing process 1 of the thin-film magnetic head.

FIG. 4 is a main-portion cross-sectional view showing the manufacturing step 2 of the thin-film magnetic head.

FIG. 5 is a main-portion cross-sectional view showing the manufacturing process 3 of the thin-film magnetic head.

FIG. 6 is a sectional view of a key portion showing a manufacturing step 4 of the thin film magnetic head.

FIG. 7 is a main-portion cross-sectional view showing the manufacturing step 5 of the thin-film magnetic head.

FIG. 8 is a main-portion cross-sectional view showing the manufacturing step 6 of the thin-film magnetic head.

FIG. 9 is a sectional view of a key portion showing a manufacturing step 7 of the thin film magnetic head.

FIG. 10 is a sectional view of a key portion showing a manufacturing step 8 of the thin film magnetic head.

FIG. 11 is a sectional view of a key portion showing a manufacturing step 9 of the thin film magnetic head.

FIG. 12 is a main-portion cross-sectional view showing the manufacturing process 10 of the thin-film magnetic head.

FIG. 13 is a main-portion cross-sectional view showing the manufacturing step 11 of the thin-film magnetic head.

FIG. 14 is a cross-sectional view showing an ideal covering state of an insulating layer when there is a stepped portion such as a core.

FIG. 15 is a cross-sectional view when abnormal crystal growth occurs in a step portion in the case of forming an Al ₂ O ₃ insulating layer.

[Explanation of symbols]

1 ... Substrate, 2,3,4,5,6,7 ... Insulating layer, 8 ... Lower core, 9a, 9b ...
Intermediate core, 10 ... upper core, 11 ... coil pattern, 12 ... protective film.

Claims (3)

[Claims] 1. A method of manufacturing a thin film magnetic head in which a core and a coil pattern are embedded in an insulating layer, wherein an insulating layer is formed by amorphizing a material containing TiO ₂ as a main component. Production method. 2. A method of manufacturing a thin film magnetic head according to claim 1, wherein the material containing TiO ₂ as a main component is an oxide to which 30% or less of mol% of TiO ₂ is added. 3. The oxide added to TiO ₂ is SiO ₂ .
3. The method for manufacturing a thin film magnetic head according to claim ₂ , wherein the added amount is 5% to 30% in mol% with respect to TiO ₂ .