JPH0583964B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a thin film magnetic head with excellent durability, weather resistance and reliability. Prior Art In thin film magnetic heads for tapes, etc., a protective substrate is adhered onto the thin film head component to protect the thin film head component, improve wear resistance, improve tape touch, etc. to achieve this purpose. Conventionally, organic adhesives have been mainly used to bond thin film head components and protective substrates due to their ease of production, but bonding protective substrates with organic adhesives lacks durability and is difficult to protect. There was a high incidence of peeling and shifting of the substrate, local wear of the adhesive layer, etc., and product reliability was a problem. Therefore, as a countermeasure, a thin plate 4 of low melting point glass is sandwiched between the protective substrate 1 and the thin film head component 3 formed on the substrate 2 as shown in FIG. A head assembly 5 was made by heating the glass to a temperature above the softening point of the low melting point glass, and the front end surface 6 of the glass was cut into a round shape as shown in FIG. 5 to make a thin film magnetic head. Furthermore, a low melting point glass layer 8 is provided in advance on the protective substrate 7 as shown in FIG. 6 by screen printing or the like.
After further heating and fusing, the substrate 9 is bonded as shown in FIG.
A method of bonding the protective substrate by bringing it into contact with the thin film head component 10 formed above and heating it to a temperature above the softening point of the low melting point glass has been devised, and has been implemented in some thin film magnetic heads. Ta. To explain this in more detail, a conventional thin film magnetic head using low melting point glass has the following components laminated on a substrate 11 as illustrated in FIG. That is, an insulating layer 12, an insulating layer 13, a conductor layer 14 for bias application, an MR magnetic layer 1 made of permalloy, etc.
5, wiring conductor layer 16, insulating layer 17, insulating layer 1
8. Consists of a shielding magnetic layer 19, a protective layer 20, a protective layer 21, a low melting point glass layer 22, and a protective substrate 23, and the front end surface is a tape sliding contact surface 24. In order to alleviate such thermal stress on the thin film magnetic head and to avoid deterioration of the magnetic properties of the magnetic layers 15 and 19 due to heat, PbO, which can be bonded at low temperatures, is generally used.
B ₂ O ₃ glass was used. Problems to be Solved by the Invention However, when using conventional PbO・B ₂ O ₃ based low melting point glass, there is a problem with moisture resistance, for example at a temperature of 60℃,
The low melting point glass layer 22 that appears on the tape sliding contact surface 24 when left for 96 hours under high temperature and high humidity conditions with a relative humidity of 95%.
It became clear that the surface of the material was significantly altered.
Due to the deterioration of the surface of the low melting point glass layer 22, convex portions 2 as shown in FIGS. 9a and 9b are formed on the tape sliding surface 24.
5. Concave portions 26 occur, resulting in poor contact with the tape and deterioration of head characteristics due to clogging of magnetic powder on the tape.Due to the occurrence of concave portions, the thin film head components, that is, from the insulating layer 12 to the protective layer 21, occur when the tape is running.
The collapse of the magnetic layers 15 and 19 caused by this collapse
Corrosion was becoming a problem. The present invention solves the above-mentioned conventional problems, and aims to provide a thin film magnetic head with excellent durability, weather resistance, and reliability. Means for Solving the Problems In order to solve the above-mentioned problems, the present invention integrates a thin film head component formed on a substrate with another substrate that protects the thin film head component using glass, The composition of the adhesive glass is PbO 30-58%, B ₂ O ₃ 2-15%, SiO ₂ 20-47 in mol%.
%, _{Al2O3 0} ~15%, ZnO0~15%, R2O0 _~ 20%
(However, R ₂ O includes one or the sum of two or more of Na ₂ O, K ₂ O, and Li ₂ O). Effects The present invention uses glass having excellent durability, weather resistance, and reliability to suppress deterioration of the characteristics of the thin film magnetic head due to the above-described configuration. Embodiment Hereinafter, an embodiment of the present invention will be described based on the drawings. First, in order to construct the thin film magnetic head of the present invention, the composition of the glass used for adhering the thin film head component and the protective substrate is as follows.

[Table] Furthermore, the expansion coefficient of the glass can be adjusted by adding Al ₂ O ₃ .ZnO and R ₂ O (one or more of NaO, K ₂ O, and Li ₂ O). Although Al ₂ O ₃ reduces the expansion of the glass and has a favorable effect on the water resistance and moisture resistance of the glass, it increases the viscosity of the glass, and if it exceeds 15 mol %, sealing will not be possible at low temperatures. ZnO reduces the expansion without changing the viscosity of the glass much, but it increases the tendency of the glass to devitrify, and if it exceeds 15 mol%, it becomes impossible to obtain a homogeneous glass. Although R ₂ O increases the expansion of the glass and also reduces the viscosity, it increases the tendency of the glass to devitrify, and if it exceeds 20 mol %, a homogeneous glass cannot be obtained. The evaluation of these glasses was carried out on a single glass block.

【table】

[Table] Moisture resistance: After the glass surface is mirror-polished with cerium oxide, it is treated at a temperature of 90℃ and a relative humidity of 95% (hereinafter written as %RH) for 24 hours (hereinafter written as hr). A glass according to an embodiment of the invention,
No. 5 is conventional glass. No. 1 to 3 are 90℃, 95
Even when left for 24 hours under %RH conditions, there was almost no change and the result was good. Regarding No. 4, the surface was only slightly cloudy. However, the surface of conventional product No. 5 became completely cloudy. Next, a thin film magnetic head made using the glass having the above structure will be explained. The thin film head component is made of Mn-Zn-ferrite (α=120×
10 ^-7 /℃) as the substrate 11, and a SiO ₂ insulating layer 1 on top.
2, Al ₂ O ₃ insulating layer 13, Ti conductor layer 14, permalloy magnetic layer 15, Au/Cr conductor layer 16, SiO insulating layer 17, SiO ₂ insulating layer 18, permalloy magnetic layer 19,
This was carried out using a shunt bias type multi-track reproducing head in which a SiO protective layer 20 and a SiO ₂ protective layer 21 were formed. The bonding of the protective substrate is shown in Figure 6, which is explained using the conventional method.
The Mn
- After attaching a frit of 150 meshes or less of glass (No. 1 in the above table) to a protective substrate made of Zn-ferrite by screen printing, and heating and fusing it to form a glass layer, the above thin film head structure was formed. to the department
The test was carried out under the conditions of heating and pressurizing at 550°C in an N ₂ atmosphere for 10 minutes. After the head is assembled, as shown in FIG. 8, a low melting point glass layer 22 according to the present invention is formed between the protective substrate 23 and the SiO ₂ protective layer 21 which is the uppermost layer of the thin film head component. The protective substrate 23 must be bonded to the thin film head component at a temperature below 600°C; exceeding this temperature may cause damage to the thin film head component and damage to the magnetic layer 1.
5, 19, the magnetic properties frequently deteriorate, and in consideration of yield, it is necessary to carry out the process at a temperature of 550° C. or lower.
All glasses according to the present invention can be bonded at temperatures below 550°C, and the yield of the thin film magnetic heads produced in this example was good. Regarding the head characteristics, not only the initial performance but also the surface of the low melting point glass layer 22 according to the present invention hardly changes after the humidity test at 60°C, 95% RH, 96 hours, and therefore the head output and output waveform It met all specifications such as second-order distortion and third-order harmonics. Furthermore, as an example, a thin-film magnetic head having a simple structure as shown in FIGS. They were created using the same process and structure and compared. In FIGS. 1 and 2, 31 is a substrate, 32 is a magnetic layer, and 33
34 is a wiring conductor layer that conducts current to the magnetic layer 32;
35 is a low melting point glass layer, and 36 is a protective substrate. Reference numeral 37 denotes a tape sliding surface, and the sliding surface 37 is created by cutting from the left end to an imaginary line showing the sliding surface 37 (see FIG. 1). The substrate 31 and the protective substrate 36 that serve as the base for forming the thin film head are made of soda lime glass (μ=93×10 ^-3 , softening point MP=720
℃). There is no difference between the MR head of the present invention and the conventional MR head shown in Figs. 1 and 2 after assembly, and the appearance and head characteristics are good. In the magnetic head using the magnetic head, the glass layer 35 on the tape sliding contact surface 37 was significantly deteriorated, and roughness was observed. Furthermore, under the above environment
After 1000 hours, in the thin film magnetic head using the glass according to the present invention, there is almost no change in the glass layer 35 on the tape sliding contact surface 37 except for a slight discoloration in a part. The head characteristics also maintained their initial characteristics and there were no abnormalities. As described above, in thin film magnetic heads, slight deterioration of the glass surface, which is not a problem in normal applications, poses a major problem, and this is where the use of glass with a limited composition in the present invention is significant. Effects of the Invention As described above, according to the present invention, in terms of mol% ratio,
PbO30~58%, _{B2O3 2} ~15%, _SiO2 20~47%,
The thin film head component and the protective substrate are bonded using glass containing components in the range of 0 to 15% Al ₂ O ₃ , 0 to 15% ZnO, and 0 to 20% R ₂ O, ensuring durability. It is possible to provide a thin film magnetic head with excellent durability, weather resistance, and reliability.

[Brief explanation of the drawing]

1 and 2 are cutaway perspective views and vertical cross-sectional views of essential parts for explaining one embodiment of the present invention, and FIGS. 3 to 5 are perspective views showing the manufacturing order of a conventional thin film magnetic head. 6 and 7 are perspective views showing another conventional manufacturing sequence, FIG. 8 is a vertical sectional view of a conventional thin film magnetic head, and FIGS. 9 a and b are enlarged views of main parts of a conventional thin film magnetic head. It is. 31... Substrate, 32... Magnetic layer, 33... Wiring conductor layer, 34... Protective layer, 35... Low melting point glass layer, 36... Protective substrate, 37... Tape sliding contact surface.

Claims (1)

[Claims] 1. The thin film head component formed on the substrate and the other substrate that protects the thin film head component are bonded and integrated with glass, and the composition of the adhesive glass is PbO30 to 58% in mol%, _{B2 O3} 2-15%,
_SiO2 20~47%, _{Al2O3 0} ~15%, ZnO0~15%,
A thin film magnetic head containing a component in the range of 0 to 20% R ₂ O (where R ₂ O is the sum of one or more of Na ₂ O, K ₂ O, and Li ₂ O).