JP2002100008A - Thin film magnetic head and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a thin film magnetic head in which the designed pattern forming steps are easily carried out, the production steps are simplified and the product cycle time is shortened. SOLUTION: In the working of NiFe-base alloy films for the shield film and the lower magnetic pole film of a thin film magnetic head, a spray etching method and a mixed solution of phosphoric acid, acetic acid and nitric acid are used. The designed pattern forming steps are easily carried out, the production steps are simplified and the product cycle time is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for manufacturing a thin film magnetic head which can easily and precisely process an alloy film containing NiFe as a main component for a shield film and a lower magnetic pole film. In particular, with respect to the method of manufacturing a thin film magnetic head, more specifically, in the shield film and the lower magnetic pole film, the processing is performed by wet etching so that the lower layer, for example, a sensor film as a reproducing head element is destroyed due to an electrostatic disturbance. The present invention relates to a method for manufacturing a thin-film magnetic head, which does not occur.

[0002] The present invention also relates to a thin-film magnetic head manufactured by using this thin-film magnetic head manufacturing method and a magnetic disk drive using the thin-film magnetic head. Further, the present invention is not limited to the method of manufacturing a thin film magnetic head, and it is also possible to manufacture an electronic circuit board using this method.

[0003]

2. Description of the Related Art A magnetic disk drive is required to have a higher recording density and a higher data communication speed. As for the thin film magnetic head used in this magnetic disk device, development of a recording / reproducing separation type head using a reproducing head as an MR element or a GMR element and a recording head as an inductive element is progressing. Thin-film magnetic heads have been developed with BPI
(Bits Per Inch) and TPI (Tracks Per Inch) are required to be improved, and the technology has been remarkably developed. Further, the product cycle time of the thin-film magnetic head is becoming shorter and shorter. Therefore, it is indispensable to improve the yield of forming the thin-film magnetic head element and shorten the process. Also,
Every year, cost reduction is also progressing.

Since the thin film magnetic head element forming process is formed by photolithography, the metal film can be processed by a dry etching method or a wet etching method, but the wet etching is desirable from the viewpoint of low cost and shortening of the process. . Further, the apparatus is simple and the cost is reduced.

Furthermore, the sensor film, which is the lower reproducing head element, can be prevented from being broken by static electricity. However, for example, when a wet etching method is used to process copper, it is known that it is difficult to perform etching as designed due to a large amount of undercut because isotropic etching is performed. Further, recently, an etchant used from the viewpoint of environmental problems has been limited. In consideration of this, it is necessary to perform a wet etching step.

On the other hand, in the dry etching method, ion milling capable of patterning with particularly high precision is used among the anisotropic dry etching methods. In ion milling, etching proceeds in such a manner that an etched surface is physically cut by collision of ions. In addition, as the thickness of the insulating film is further reduced, there is a concern that static electricity may be damaged. In addition, as a thing related to this kind, for example,
JP-A-5-159223 is mentioned.

[0007]

According to the above-mentioned conventional method of forming by dry etching, the etching surface is physically cut by the collision of ions. Therefore, it is damaged when over-etching is performed.
Further, a deposited layer of cutting dust of the metal film is formed around the pattern. In the case of multi-layering, the adhesion is insufficient due to the influence of the deposited layer, and the yield is reduced. Further, there is a problem that a sensor film as a lower reproducing head element is broken by an electrostatic disturbance.

An object of the present invention is to use a wet etching method which does not cause the above-mentioned problems in the dry etching method and greatly reduce the amount of undercut which was the only problem, thereby facilitating a pattern forming step as designed. An object of the present invention is to provide a method of manufacturing a thin-film magnetic head which can be manufactured at a low cost.

Another object of the present invention is to provide a method of manufacturing a thin-film magnetic head in which the manufacturing process is simplified and the product cycle time is shortened.

Another object of the present invention is to realize a high-performance magnetic disk drive using the thin-film magnetic head.

[0011]

In order to solve the above-mentioned problems, the present invention mainly employs the following configuration. An alloy containing NiFe as a main component was formed by electroplating on the shield film and the lower magnetic pole film, and various experiments were conducted on the pattern forming method using a wet etching method.
First, in order to accurately process the metal film by wet etching, the chemical resistance of the resist used as a pattern mask for processing, the amount of undercut, the presence or absence of damage to the underlying film by the etching solution, etc. are taken into consideration. If you do it, you can not go.

When the metal film is in a laminated state of several types, selectivity with another metal is essential. In particular,
In the case of a laminated film, the amount of undercut is an important parameter that determines the processing accuracy because the film on the metal film to be etched functions as a pattern mask. The magnitude of the amount of undercut greatly varies depending on conditions such as the type of the etching solution, the temperature of the etching solution, the etching method, and the like.

In wet etching, the etching rate tends to have a distribution within the plane due to factors such as uneven thickness of the material, mixing and diffusion of liquids, liquid temperature, and reactive organisms. It is hard to be simultaneous over the entire material surface. Therefore, the end point of the latest portion of the etching is set as the end point of the etching. Since there is no strict method for confirming the end point, the etching time is generally made longer. Therefore, if the over-etching time is too long, the amount of undercut inevitably increases and the pattern size decreases.

Further, the amount of undercut is related to the thickness of the metal film to be etched. For example, when a thin film is etched, when the etching in the depth direction is completed, the etching in the lateral direction has a small film thickness, so that the etching solution is less penetrated and the amount of undercut is small. On the other hand, when the film thickness is large, the amount of undercut tends to be large because the etching in the lateral direction simultaneously proceeds with the etching in the depth direction.

Based on the above idea, a spray etching method is used as an etching method, and a mixed solution of phosphoric acid, acetic acid and nitric acid is used as an etching solution at that time, so that the amount of undercut can be greatly reduced, and the pattern as designed can be reduced. An object of the present invention is to provide a method for manufacturing a thin-film magnetic head by finding that the formation process can be facilitated.

The details will be described below.

The mechanism of the method of reducing the amount of undercut in the spray etching method is that the etching solution is accelerated by a pump, and the impact of the etching solution on the surface of the metal to be etched enhances the etching of the bottom which is strongly impacted, and the side wall portion Is an etching method utilizing the fact that it is difficult to etch due to a weak impact. The amount of undercut is reduced by this etching method. This method is commonly used. In order to reduce the amount of undercut, a solution was achieved by using this method and a mixed solution of phosphoric acid, acetic acid and nitric acid as an etching solution.
This etchant was considered to have a high viscosity of phosphoric acid occupying about 80% of the whole, so that the diffusion in the lateral direction was further suppressed and the amount of undercut could be greatly reduced. It is an object of the present invention to provide a method of manufacturing a thin-film magnetic head which can be easily manufactured by finding that a pattern can be formed as designed and can be manufactured at low cost.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A thin-film magnetic head according to an embodiment of the present invention and a method for manufacturing the same will be described below.

An embodiment will be described in detail with reference to FIG. First, the sample used in the experiment of the present invention will be described. Using a 5-inch diameter glass substrate as a substrate, a process of sputter-depositing a NiCr (nickel / chromium) alloy film as a base film (seed film) adhesion film that enables a plating power supply film. Forming a base film (seed film) NiFe (nickel / iron) alloy film by sputtering.

The sputtering conditions are as follows.

Sputtering conditions 1) Sputter etching Input power = 0.25 kW (4 minutes) 0.50 kW (2 minutes) Ar pressure = 8 × 10 ⁵ Pa 2) Adhesion layer Nickel-chromium alloy layer sputtering Input power (RF) = 1.0 kW Ar pressure = 0.02 Pa Film thickness: 0.005 µm 3) Underlayer nickel / iron alloy film sputtering Input power (RF) = 1.0 kW Ar pressure = 0.02 Pa Film thickness: 0.15 µm Is not limited to NiCr alloy film
(Cr) film, titanium (Ti) film, tantalum (Ta) film, niobium
(Nb) film is also possible.

A step (2) of plating an alloy containing NiFe as a main component on the substrate formed as described above by electroplating.

The conditions are as follows.

Liquid composition Metal ion concentration: Fe (2+) 0.5 to 1.5 g / L Ni (2+) 10 to 30 g / L Saccharin sodium: 1.0 to 2.0 g / L Boric acid: 20 to 30 g / L Liter Sodium chloride: 20-30 g / liter Conditions Liquid temperature: 30 ° C. pH = 3.6 Film thickness: 3.5-4.0 μm Current density: The current value I at the start of plating and the application time t are I ₁ = 160 mA ( i = 1.42mA / cm ² ) Set t ₁ = 120sec on the low current side, then I ₂ = 240mA (i = 2.13mA / cm ² ), t ₂ = 30sec, I ₃ = 360mA (i = 3.20mA / Cm ² ), ₃ = 30 sec I ₄ = 420 mA (i = 3.73 mA / cm ² ), t ₄ = 150 sec, I ₅ = 440 mA, (i = 3.91 mA / cm ² ), t ₅ = 180 sec, I ₆ = 445 mA (I = 3.96mA / cm ² ), t ₆ = 1125sec, I ₇ = 450mA, (i = 4.00mA / cm ² ) t ₇ = 1125sec Adoption.

A resist pattern is formed on the alloy film containing NiFe as a main component and having a thickness of 6 μm or more under predetermined conditions as described above (3). Next, using this resist as a mask, the NiF
Etching of an alloy film containing e as a main component is performed. continue,
Etching the nickel-chromium alloy film on the adhesion film of the base film where the alloy film containing NiFe as a main component has disappeared
(4). After cleaning and drying the substrate after each of the above steps, the resist is stripped using a resist stripper (5). An insulating film is coated on the entire surface of the substrate, and a through-hole for electrically connecting to the insulating film is provided (6), and an adhesion film of a base film (seed film) that enables a plating power supply film by forming a lower magnetic pole film. A step of forming a nickel-chromium alloy film by sputtering, a step of forming a base film (seed film) of a nickel / iron alloy film by sputtering to enable a plating power supply film (7), and an electroplating method over the entire surface of the substrate. (8) plating an alloy containing NiFe as a main component,
Next, a step (9) of selectively forming a pattern made of an organic material by a photolithography technique on a portion where an alloy film containing NiFe as a main component is left as a pattern by electroplating, and then, forming a pattern of the organic material on the substrate. The step of removing the alloy film containing NiFe as a main component by wet etching at the place where there is not, followed by the step (10) of removing the adhesion film of the alloy film containing NiFe as a main component by wet etching, and the above steps are completed. Cleaning and drying the substrate, and removing the pattern made of an organic material using a resist removing solution (1).
1) After the above steps, the N of the shield film and the lower magnetic pole film
This means that the pattern formation of the alloy film containing iFe as a main component was completed. This step greatly affects post-write noise and output fluctuations associated with higher recording density and higher speed communication of the magnetic disk device. Therefore, since the characteristics of these two films affect the characteristics of the thin-film magnetic head, it is the most important task to form a pattern as designed. Therefore, Table 1
Various investigations were carried out by changing the liquid composition and conditions shown in FIG.

[0026]

[Table 1]

Here, the undercut amount shown in Table 1 is
It is displayed by the length indicated as undercut amount L ₁ of the shield film to Hotoreji 1 (4) showing the etching after the state of the shielding film. Also displayed a length indicating the undercut amount L ₂ of the lower magnetic pole layer for Hotoreji 1 (10) showing the etching after the state of the lower magnetic pole layer. After etching, the pattern shape was observed with a metallographic microscope.

In Table 1, No. 1 and No. 2 are ferric chloride-based, which is a general etching solution for an alloy film material containing NiFe as a main component. In the case of the dip etching method shown in No. 1, the amount of undercut was large in both the shield film and the lower magnetic pole film, and the end portions were jagged, so that a pattern could not be formed as designed. No. 2 was performed by the spray etching method, and the undercut amount of both the shield film and the lower magnetic pole film could be reduced as compared with the dip etching method. This is due to the effect of spraying the etching liquid as described above. However, although the end portion shape was good, the amount of undercut was large and the pattern could not be formed as intended.

After various examinations, Table 1 shows that No. 3 to No.
8 is a case of a phosphoric acid, acetic acid, and nitric acid based etchant. In cases where the etching method, liquid temperature, and spray pressure were changed, when the liquid temperature was increased, and when the spray pressure was increased, the amount of undercut could be significantly reduced, and No. 6, No.
As shown in Nos. 7 and 8, it was found that both the shield film and the lower magnetic pole film had almost the same dimensions as the resist. Also,
As shown in No. 7, similar results were obtained even when the etching time was twice or more. That is, it can be said that the processing time at the time of pattern formation is extremely wide.

As described above, it has been found that the alloy film containing NiFe as the main component, which is the shield film and the lower magnetic pole film of the thin-film magnetic head, enables the pattern formation as designed, and can be easily manufactured and at a low cost. It was shown that a method of manufacturing a thin-film magnetic head which achieved the above was achieved. Therefore,
Using the present invention, a thin-film magnetic head shown in FIG. 2 was prepared and a magnetic disk drive was manufactured, and extremely good results were obtained.

[0031]

As described above in detail, according to the present invention, in a thin film magnetic head used in a magnetic recording apparatus having a write head and a read head Ｎｉ, NiFe which is a shield film and a lower magnetic pole film is mainly used. By significantly reducing the amount of undercut of the alloy film as a component, a pattern forming process as designed can be easily manufactured, and the cost can be reduced.

Further, a method of manufacturing a thin-film magnetic head in which the product cycle time is shortened by simplifying the manufacturing process has been realized. Further, by using this thin-film magnetic head, it is possible to provide a magnetic disk device with high recording density and high-speed communication.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a manufacturing process according to an embodiment of the present invention.

FIG. 2 is a schematic view of a thin-film magnetic head manufactured using the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 2 ... Sputtered nickel / Nichrome alloy film, 3 ... Sputtered nickel / iron alloy film, 4 ... Plated nickel / iron alloy film, 5 ... Photoresist, 6 ... Insulating film, 10
... top writing pole, 11 ... GAP, 12 ... coil,
13: insulating film, 14: lower shield, 15: upper shield, 16: MR sensor part, 17: hard bias layer and electrode layer, 18: substrate.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Noriyuki Saiki 2880 Kozu, Kodahara City, Kanagawa Prefecture Inside the Storage Systems Division of Hitachi, Ltd. 5D033 AA02 BA03 BA71 BB22 BB43 CA08 DA07 DA09

Claims (5)

[Claims] In a thin-film magnetic head used in a magnetic recording apparatus having a recording head and a reproducing head, a ferromagnetic material is disposed around a sensor film as a reproducing head element, and the ferromagnetic material is There is a film having soft magnetic characteristics and a magnetic shielding function, and there is a lower magnetic pole film having soft magnetic characteristics via an insulating film thereon,
These two films are formed by sputtering a base film (seed film) that enables electroplating with an alloy containing NiFe (nickel / iron) as a main component and then increasing the film thickness by electroplating on the base film. The film thickness, composition, and magnetic characteristics are assured, and the entire film is processed into the desired shape by the photolithography technique, and the processing is performed by wet etching so that the lower layer film is not damaged. Thin film magnetic head. 2. A thin film magnetic head for use in a magnetic recording device having a recording head and a reproducing head, wherein a film having a magnetic shielding function is first formed on a substrate.
An adhesion film of a base film that enables a plating power supply film, followed by N
a step of sputtering an alloy film containing iFe as a main component,
A step of plating an alloy film containing NiFe as a main component on the entire surface of the substrate by electroplating, and then selectively leaving a portion of the alloy film containing NiFe as a main component as a pattern by electroplating from an organic material by photolithography. Forming a pattern, and then removing the NiFe-based alloy by wet etching where there is no pattern made of an organic material on the substrate by wet etching, followed by adhesion of the NiFe-based alloy film. A step of removing the film by wet etching, a step of washing and drying the substrate after each of the above steps, and a step of peeling off a pattern made of an organic material using a resist stripping solution; and covering the entire surface of the substrate with an insulating film. Through holes for electrical connection, and then an adhesion film of a base film that enables a plating power supply film by forming a lower magnetic pole film. Step of depositing an alloy film containing NiFe as a main component by sputtering, plating an alloy containing NiFe as a main component on the entire surface of the substrate by electroplating, and selectively leaving an alloy film containing NiFe as a main component as a pattern. Forming a pattern made of an organic material by photolithography technology,
Next, N where there is no pattern made of an organic material on the substrate
removing the alloy film containing iFe as a main component by wet etching; subsequently, removing the adhesive film of the alloy film containing NiFe as a main component by wet etching;
After washing and drying the substrate after each of the above steps, a step of peeling a pattern made of an organic material using a resist stripper,
And a step of forming a shield film and a lower magnetic pole film. 3. In a thin-film magnetic head used in a magnetic recording apparatus having a recording head and a reproducing head, wet etching of an alloy film containing NiFe as a main component of a shield film and a lower magnetic pole film is performed by a spray etching method. 3. The method of manufacturing a thin-film magnetic head according to claim 2, wherein: 4. In a thin-film magnetic head used for a magnetic recording apparatus having a recording head and a reproducing head, phosphoric acid or phosphoric acid is used as an etchant used in a spray etching method when wet-etching an alloy containing NiFe as a main component. 3. The method for manufacturing a thin film magnetic head according to claim 2, wherein the method is performed with a mixed solution of acetic acid and nitric acid. 5. The claim 1, claim 2, or claim 3.
6. A magnetic disk drive using the thin-film magnetic head according to 1.