JPS6228909A - Magnetic head and its manufacture - Google Patents

Abstract

PURPOSE:To reduce the production of air bubbles and to make an effective gap coincident with an optical gap by forming high-melting-point oxide films of SiO2, etc., on the opposite surfaces of ferromagnetic oxide cores and charging glass which has a lower fusion point than the films and contains 2-15wt% Fe2O3 between those films. CONSTITUTION:A couple of ferromagnetic oxide cores 1 and 1' are arranged on a magnetic head and a groove 4 for winding is formed in the opposite surface between the oxide cores 1 and 1'. Further, the high-melting-point oxide films 8 of SiO2, etc., are formed in the gap 7 in the opposite surface atop the reinforcing glass 5a between the oxide cores 1 and 1'. Further, the glass 9 which has a lower fusion point than the oxide films 8 and contains 2-15wt% is charged between the oxide films 8. Then air bubbles produced during manufacture are reduced and the effective gap of gap 7 of the oxide cores 1 and 1' is made coincident with the optical gap to improve corrosion resistance.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magnetic head having high precision and high reliability, such as a magnetic head for a VTR, a magnetic head for a floppy disk drive, or a magnetic head used for a hard disk for a computer. and its manufacturing method.

[Conventional technology]

Magnetic heads used for VTR170 tsupi magnetic disk drives or computer hard disk drives have high recording frequencies and are required to have high resolution. Therefore, strict processing precision is required in the manufacturing process. In particular, when talking about the accuracy of the magnetic head gap, the head gap length is 0.5
~2.0μαj, and its manufacturing tolerance is ±0.05~
It must meet strict specifications such as 0.2 μm.

In addition, there is little difference in wear resistance between the formed gap and the ferromagnetic oxide that is the core, the adhesion strength of the gap is strong, and the i'' is sufficiently erodible. Various requirements have been made from the viewpoints of processability in manufacturing the magnetic head and reliability and reliability of the finished product, such as that the optical gap length of the gap and the effective gap length be approximately equal.

The conventional manufacturing method for magnetic heads involves creating a gap between the two cores using a spacer of a predetermined thickness, and then introducing molten glass into the gap by capillary action. 2837f3 Publication) has also been considered, but while this method 1 ensures sufficient bonding between the core and the glass material, it also increases the bonding layer between the core and glass, resulting in an optical gap and an effective gap length. Furthermore, there is a problem that accuracy is not achieved because the spacer is located at a location far from the gap portion to be controlled.

Further, in the above method, a glass material that forms a gap is attached to the gap forming surface of the core by vapor deposition or sputtering and is bonded under heat (Japanese Patent Publication No. 47-26336). A method in which a wire with a lower softening point is placed in the winding window, and the core that has been heat-pressed is heated again and melted and bonded to strengthen it (
Tokuko Showa 47. -268 Publication), a method using S + 02 film as a gap inclusion (Japanese Patent Publication No. 43-30386
Publication No.) etc. have been proposed.

In addition, recently, after depositing an oxide film such as 5iOa on the core of a magnetic material by using the sputtering method, they are butted together and filled with reinforcing glass while heating and pressurizing. What created the gap was
It has become mainstream not only for VTR heads but also for other magnetic heads.

As described above, the gap forming method using the sputtering method can create a highly accurate gap length. However, this method also has the problem of lowering reliability and yield when manufacturing magnetic heads.

The manufacturing process and problems are described below.

[Problem that the invention seeks to solve]

For example, as shown in the perspective view of FIG. 2, in the conventional magnetic helad chip manufacturing process, first a groove 4 for winding is provided in one core 1, and the gap facing surface 2.2' is mirror-finished. The second step is to form an oxide film on the surface of the elbow core 1.1'.
Figure (a)), butt their cores 1.1' and groove 4
Insert the lath rod 5 for reinforcement (Fig. 2(b)),
By heating and pressurizing it, the lath rod 5 is melted and bonded, thereby manufacturing the magnetic held bonding core 3 (FIG. 2(C)).

During the heating process, bubbles 6 as shown in FIG. 3 are generated in the gap or inside the glass used for reinforcement. Among these bubbles 6, the hard magnetic powder of the recording medium such as the magnetic head and disk (or tape) caused by wear is embedded in the bubbles 6 existing in the gap 7, causing deterioration of characteristics and reliability. arise.

Moreover, the bubbles 6 existing in the reinforced glass become a factor of deterioration of characteristics and become a starting point for cracks in the subsequent magnetic rad core processing.

As mentioned above, air bubbles generated in the gap or glass of the magnetic head are a serious obstacle to improving yield or reliability in manufacturing the magnetic head.

In manufacturing a magnetic head, the inventors of the present invention have conducted intensive studies on reducing the gap and the bubbles generated in the reinforcing glass.

It is an object of the present invention to meet all the requirements of conventional magnetic heads, such as significantly reducing the above-mentioned air bubbles, being highly corrosion resistant, and having the optical gap and the effective gap almost coincide with each other. The purpose of the present invention is to provide a magnetic head having a structure that satisfies the above requirements and a method for manufacturing the same.

[Means for solving the problems] [The magnetic head of the present invention has grooves 4 for windings as shown in FIG.
At least one of the opposing surfaces 2.2' of the ferromagnetic core 1.1' processed into a predetermined shape is finished to a mirror finish, and the opposing surfaces 2.2' have a predetermined film thickness) To,
A high melting point oxide film such as SiO2 is deposited as the first layer by sputtering, and then Fe2O3 is deposited as the first layer.
A glass film containing 5'wt% was deposited as a second layer by sputtering, and the opposite surface 2.2 was coated via these films.
''After they are butted together, a reinforcing glass rod 5 or glass powder is placed in the groove 4, and by applying pressure and heating, the gap part is bonded and the reinforcing glass is melted and fixed at the same time. be done.

=7-' [Function] 2 to 15 wt% Fe2O as the second layer glass
By using the containing glass, the following actions and effects can be achieved in reducing the generation of bubbles in the process of manufacturing magnetic heads.・Fe2O for 1 glass film
It is known that the temperature change in viscosity of glass containing No. 3 becomes gradual. Regarding the glass actually obtained in this research, if the viscosity is 9, log η is taken as a representative viscosity value, and the viscosity of the glass is i'o
If the temperature difference changing from g171=, 11 to 1og+72=7.65 is ΔT, then Fe20 in the glass outside
, the content increases from 0 to 15 wt%, and as it goes from L, the 8T increases to 100 to 180°C.

In the process of research to determine the cause of bubbles in the manufacturing process of magnetic heads, the present inventors conducted a heat treatment process to prevent the spuck atoms incorporated into the film during film formation using the sputtering method from bonding the magnetic head. During the process, the viscosity decreased °-8 = It is released into the glass, and the volume increases due to growth, aggregation, and aggregation, which is an unexpected cause of bubble generation6. revealed the above.

The sputtered glass film was heated in a vacuum, and the amount of ArJ released from the glass film under various temperature conditions was investigated.
'i'0□-log 173 for B203 series glass
Gas is released around 7. In this viscosity range, the released gas grows or collects in the gap forming member, as described above. However, it has been found that in SiO2, the gas release is completed at 350 to 600°C, which is almost a solid state. It is thought that the relationship between this release temperature and viscosity is largely dependent on the diffusion coefficient of the gas in the glass. As a result of studying to create a glass with a low glass odor but with properties similar to SiO□, we found that PbO-8i "02~' B
By adding Fe2O3 to the 203 series glass, the temperature change in the viscosity coefficient of the glass becomes gradual, and gas release becomes possible within the viscosity range of RoH1; 7 to 4, making it possible to We have discovered a glass that can be bonded. In the above viscosity range, the phenomenon that the emitted gas grows or aggregates in the gap forming member hardly occurs.

That is, in the magnetic head manufacturing process described above,
Gap formation is possible using a method in which sputtered atoms that cause bubbles are emitted under conditions that do not allow bubbles to grow or aggregate in the gap forming member, and then bonding is performed. This results in a significant reduction in the formation of air bubbles in the component.

Furthermore, the glass used for reinforcement at this time has a softening point that is the same or higher than that of the glass of the second layer, so that the effect of reducing bubble generation in the reinforcement glass is better.

In addition, by using glass with almost the same composition as the second layer of glass formed on the opposing surface of the core as the reinforcing glass, gas incorporation into the reinforcing glass is reduced.
Then, by performing melt bonding, the generation of bubbles in the reinforced glass can be reduced.

Furthermore, the magnetic head manufactured by the above-described process using glass containing Fe2O3 has the following functions and effects.

By containing Fe2O3, this glass not only slows the change in viscosity with temperature, but also greatly improves corrosion resistance, so that the corrosion resistance of the completed magnetic head is also greatly improved.

Furthermore, by using a high melting point oxide as the first layer of the gap forming member, the first layer of high melting point oxide and the second layer
Mutual diffusion during heat treatment for adhesion at the interface between the opposing surfaces of the glass layer and the magnetic core is suppressed, and there is almost no difference between the optical gap and the effective gap.

In the present invention, the Fe203 content in the glass is reduced to 2
~15wt% is specified because less than 2wt%, F
e The effect of adding 203 was not sufficiently apparent, and the addition of 15.1%
This is because if it exceeds this, there is a greater possibility that the produced glass will devitrify, making it impossible to use it as a gap or reinforcing glass member.

In addition, the overall glass composition is determined by the glass conditions necessary to bond ferrite-based ferromagnetic oxides and provide corrosion resistance and heat resistance, with a softening point range of 500 to 650°C. and thermal expansion coefficient 75~120X10
This is to obtain a glass of -7/'C.

〔Example〕

The present invention will be explained in detail below using examples.

(Example 1) First, as shown in FIG.
A core 1.1' of M n Z n 7 elite, which was lapped to a mirror surface, was prepared.

After cleaning this, it was installed inside the sample chamber of the sputtering apparatus. Next, first heat this to about 300℃,
It was evacuated to a vacuum level of I x 10 '' Torr (this exhaust ended by removing moisture and gas adsorbed on the ferrite core). After evacuation to a predetermined degree of vacuum, Ar gas was introduced while heating was maintained.

This gas is introduced through the mass 70-controller;
For sputtering chamber content #It2001, A" is 80SC.
It is controlled by CM.

Also, the total pressure of the subtube is 5 x 10'-3 Torr.
Controlled to r.

Furthermore, after leaving it until the gas pressure stabilized, 13.5
A high frequency power of about 400 W/cI112 of 6 MHz was applied, and press sputtering was performed for 20 minutes for the purpose of cleaning the target surface. After that, 5in2 as the first layer
and further, as a second layer, F e 20 s
A glass film containing 2-15+ut% of was deposited.

The film thickness of each core is approximately 1/2 of the gear ring that is to be formed by the sum of the first layer and the second layer, and the ratio of the film thickness of the first scrap and the second layer is determined from the viewpoint of gap accuracy. A range of from 7:3 to 19:1 is preferable.

The target used for sputtering is that the first layer is S + 0
Sputtering was performed using a planar magnetron method using two plates, and the second layer was a glass plate prepared so that the formed film had the target composition.

The typical positive composition used in this example was 5if237.5% in I%, B 20 s 2 .

5%, PbO 33.8%, Al2O, 0.9%,
Na2O4, 1%, K2O8, 1%, Fe2o 38
.

1%, its softening point is 556°C, and a is 108
10-'/''C.

Next, after assembling these cores by aligning them outwardly with each other, a reinforcing glass rod 5 is inserted into the winding groove 4.
The glass rod 5 was melted and filled by heating at a temperature approximately 130° C. higher than the softening point of the glass rod 5 and holding it for a predetermined time. The temperature increase rate at this time was approximately °C/min.

In the magnetic head chip manufactured by such a process, as shown in FIG. 3, air bubbles in the gap 7 and the reinforcing glass 5a are significantly reduced.

The structure of the magnetic head at this time is as shown in FIG. That is, 1.1' is the ferromagnetic core, and 5a is the groove 4.
8.8 is the first layer of oxide film, and 9 is the second layer of Fe2O-containing glass.

(Example 2) In the process of Example 1, glass having the above-mentioned typical composition was used as the reinforcing glass, and the glass rods were melt-filled and held at 760°C for 30 minutes.
The effect of reducing air bubbles was observed.

(Example 3) In the process of Example 2, the magnetic core was made of Ni'Zn.
7 elite and SiO,53 w't% as glass
,0%, 82032.0%, PbO28,0%, Al2
O, 0,7%, N IL20 3, 3%, K2O6,
5%, Fe2036.5%, its softening point is 650℃, and a is 8'OX 10-7/'C.
-152 was used and the glass rods were melt-filled and held at 850° C. for 30 minutes, and bubbles were also reduced.

In Examples 1 to 3, the softening point and coefficient of thermal expansion of the glass were optimized by taking into consideration the maximum treatment temperature and coefficient of thermal expansion of each of the seven elites.

(Example 4) In order to further reduce air bubbles, preheating for removing bubbles was performed at a temperature approximately 10°C higher than the melt filling temperature of the glass before the heat treatment for joining the cores, especially in Example 1. The magnetic herad tip created in steps 3 to 3 is
Furthermore, the effect of reducing air bubbles was noticeable.

(Example 5) In order to evaluate the corrosion resistance of the glass in the present invention, Table 1 shows the results of a high temperature and high humidity test F in which the glass was left at a humidity of 95% and a temperature of 40° C. for 1000 hours. Regarding the glass for the present invention containing Fe203, no difference was observed before and after the test.

-16D (Example 6) The effective gap and optical gap of the magnetic head using the magnetic herad chip manufactured according to Example 2 are as shown in Table 2, and they almost match.

Table 2 [Effects of the Invention] As described above, the present invention enables a magnetic head that can significantly reduce the generation of bubbles during its manufacturing process, is highly corrosion resistant, and has an effective gap and an optical gap that almost match each other. is now available.

[Brief explanation of the drawing]

Figure #1 is a side view showing the structure of the magnetic head chip according to the present invention, Figures 2 (a), (b), and (c) are perspective views of each manufacturing process of the magnetic head chip, and Figure 3 is a side view showing the structure of the magnetic head chip according to the present invention. FIG. 2 is a perspective view of a main part showing a state in which bubbles are generated. 1.1': Core, 2.2' two opposing surfaces, 3: Bonding core, 4: Groove, 5: Lath bar, 5a: Reinforcement lath, 7: Gap, 8 Dioxide film, 9: Fe
2O3 Contains〃Las Agent Patent Attorney Honma
Figure 1 Figure 3 Figure 2 Figure 2

Claims (6)

[Claims] (1) In a magnetic head formed by opposing a pair of ferromagnetic oxide cores, high melting point oxide films such as SiO_2 are formed on the opposing surfaces of the ferromagnetic oxide cores, and these oxide films A magnetic head characterized in that glass, which has a softening point lower than that of the oxide film and contains 2 to 15 wt% of Fe_2O_3, is filled between the oxide films. (2) A magnetic head according to claim 1, characterized in that a glass having substantially the same composition as the glass for reinforcing adhesion of the ferromagnetic core is disposed near the gap surface. (3) In claim 1 or 2, F
Glass containing 2 to 15 wt% of e_2O_3, and 22 to 55 wt% of SiO_2 and 25 to 45 w of PbO.
t%, 5 to 15 wt of Na_2O and K_2O together
%, B_2O_3 from 1 to 6 wt%, Al_2O_3 to 0
A magnetic head characterized by being made of glass containing ~8 wt%, the total of which is 100%. (4) A high melting point oxide film such as SiO_2 with a predetermined thickness is formed as a first layer by sputtering on each of the opposing surfaces of a pair of ferromagnetic oxide cores having grooves on at least one side, and then 2~15w of Fe_2O_3 as the second layer
Forming a glass film containing t% and having a lower softening point than the first layer,
After these cores are butted together, a glass rod or glass powder for reinforcing the core is placed in the groove, and by applying pressure and heat, the glass is melted and both the core of the magnetic head and the gap are bonded at the same time. A method of manufacturing a magnetic head, characterized by: (5) In claim 4, the second layer contains 2 to 15 wt% of Fe_2O_3 as the core reinforcing glass.
A method for manufacturing a magnetic head using glass having almost the same composition as the glass contained therein. (6) In claim 4 or 5, Fe_
Glass containing 2 to 15 wt% of 2O_3 also contains Si.
22 to 55 wt% O_2, 25 to 45 wt% PbO,
5 to 15 wt% of Na_2O and K_2O in total, B
_2O_3 1-6wt%, Al_2O_3 0-8w
A method for manufacturing a magnetic head, characterized in that the glass contains 100% of the glass.