JP2733728B2 - Method of forming coil for thin film magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a coil for a thin-film magnetic head used in a magnetic disk device, for example, an external storage device of a computer system.

[0002]

2. Description of the Related Art FIG. 3 is a perspective view of an assembly of a thin-film magnetic head used in a conventional general magnetic disk drive. Numeral 1 denotes a thin-film magnetic head, which is attached to a tip 2a of an elastic plate 2. The base end 2b of the elastic plate 2 is adapted to be attached to a carriage arm (not shown). Reference numeral 3 denotes a lead wire connected to a terminal portion 1b connected to a coil, which will be described later, on which the electromagnetic conversion element portion 1a of the thin-film magnetic head 1 is formed.

FIG. 4 is an enlarged perspective view of the thin-film magnetic head 1. The size of the thin-film magnetic head 1 is as small as about 2.5 mm in width A, about 3 mm in depth B, and about 0.6 mm in thickness C. The terminal section 1b is connected to a coil forming an electromagnetic conversion element section 1a including a coil, a magnetic film, a read / write gap, and the like. Electromagnetic transducer 1a
Although two terminal portions 1b are formed, one of them is selected and used.

FIG. 5 is a cross-sectional view taken along the line VV of FIG. 4, and by combining thin film forming techniques such as a photolithography technique, an electroplating technique, and a vacuum deposition technique,
A base alumina film 1d is formed on a ceramic substrate 1c, a magnetic film 1e is formed on the base alumina film 1d, and a coil 1g is formed on the magnetic film 1e and the alumina film 1d via an insulating layer. To form

[0005] A magnetic film 1e 'is formed by providing a read / write gap 1f on the coil 1g, and a terminal portion 1b is formed on terminal forming portions 1i and 1i' connected to the coil 1g. An alumina protective film 1h is formed on the portion 1b and the magnetic film 1e '.
The thin film magnetic head 1 is completed by polishing the upper surface of h and the tip of the read / write gap 1f. The terminal forming portions 1i and 1i 'are displaced back and forth in the direction perpendicular to the plane of the paper, and are in a non-contact state with each other.

The coil 1g is formed as shown in FIGS.
As shown in FIG. 2, a resist 5 is applied on the magnetic film 1e and the alumina film 1d via a conductive plating base 4, and the resist 5 is patterned by photolithography to form a coil. A plating solution based on copper sulfate is put therein and electroplating is performed to form a copper film forming a coil.

After the coil 1g is formed, as shown in FIG. 7, the resist 5 and the underlying plating base 4 are removed by etching and then covered with an insulating layer (not shown).

[0008]

However, in the conventional method for forming a coil for a thin-film magnetic head as described above, as shown in FIG. Is formed into a coil 1g
However, since the current density is high, the growth of the copper film is large at both end edges 1g ', and so-called burr-like projections 1g "are formed as shown in FIGS. 6 and 7. This coil 1g , 1g is very narrow, about 2 μm, so that the projection 1g ″ may be short-circuited between the coils.

In order to prevent such a short circuit, the resist 5 is made thick. However, when the resist 5 becomes thick, a large amount of light energy is applied to perform patterning. It adversely affects patterning accuracy and the like.

When the number of turns of the coil is increased, the interval between the coil plating portions is further reduced and the number of coil layers tends to be increased. Therefore, when the resist is thickened, patterning becomes more difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and it is an object of the present invention to provide a method for forming a coil in a spiral shape to form a coil. An object of the present invention is to prevent a short circuit between coils due to protrusions formed on both side edges.

[0012]

According to the present invention, in order to solve the above-described problems, as shown in FIG. 1, a substrate 6 having a coil pattern 8 formed on a substrate 6 by a resist 7 is provided.
Is placed in a plating solution 10 in a plating tank 9, and a metal film is formed on the coil pattern 8 between the resists 7 by electroplating to form a coil 11. In the plating solution 10,
A first film forming step of forming a first metal film 11a in the coil pattern 8 between the resist 7 performs electroplating thio urea dextrin and organic compound-based polymer systems <br/> added, After performing the first film-forming step, a second film-forming step of forming a second metal film 11b thinner than the metal film 11a of the first film-forming step with the ordinary plating solution 10; And a step of removing the resist 7 of the coil pattern after performing the film forming step.

[0013]

When the first metal film 11a is formed on the coil pattern 8 between the resists 7 in the first film forming step in this method for forming a coil for a thin film magnetic head, the first metal film 11a is added to the plating solution 10. agents, i.e., by the action of thiourea-containing dextrin and organic compound-based polymer systems, poor formation of the first metal film 11a to form a coil which is coated spirally formed, i.e., the first metal film 11a No projection is formed on both side edges.

In the first film forming step, sulfur S and chlorine Cl contained in the additive are deposited in the first metal film 11a during the deposition of the first metal film 11a. They are deposited together, and this deteriorates the corrosion resistance of the first metal coating 11a in the subsequent step of removing the resist 7 or coating the insulating layer.

Therefore, by performing the second film forming step, the ordinary second metal film 1 having good corrosion resistance is formed on the first metal film 11a having no projections formed on both side edges.
By forming a thin film of 1b, the corrosion resistance in the next step is improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for forming a coil for a thin film magnetic head according to the present invention will be described below in detail with reference to FIG. 2. FIG. 9 is a schematic view of a plating apparatus, in which 9 is a plating tank in which a plating solution based on copper sulfate, for example, copper sulfate CuSO ₄ 5H ₂ O, sulfuric acid H ₂ SO ₄ , HCl hydrochloride, or the like is mixed. Liquid 10 is contained.

Reference numeral 12 denotes an anode placed in the plating tank 9;
Reference numeral 13 denotes an annular auxiliary electrode.
A substrate (wafer) 6 on which a coil pattern 8 is formed by a resist 7 is provided. The annular auxiliary electrode 13
Means that the thickness of the metal film 11 formed on the substrate 6 is
Is made uniform at the central portion and the outer peripheral portion.

The substrate 6 is connected to the (-) electrode of the substrate power supply 14, the annular auxiliary electrode 13 is connected to the (-) electrode of the auxiliary electrode power supply 15, and the anode 1
2 is (+) of the substrate power supply 14 and the auxiliary electrode power supply 15
Connected to electrodes.

Reference numeral 16 denotes a control tank, which is connected to the plating tank 9 by one pipe 17 and the other pipe 19 provided with a pump 18 so that the plating solution 10 is supplied to the plating tank 9 and the control tank 16. And the concentration of the composition of the plating solution is made uniform.

The above-described electroplating apparatus is almost the same as the conventional apparatus, and the method of forming the coil for the thin-film magnetic head of the present invention is different from that of the conventional example as described below. That is, in the first film forming step of forming a first metal film 11a in the coil pattern 8 between the resist 7, in the plating solution 10, adding thio urea dextrin and organic compound-based polymer systems And perform electroplating.

[0021] In this way, when the electroplated substrate 6 where the coil patterns 8 are formed in the resist 7 by the action of thiourea-containing dextrin and organic compound-based polymer systems, are coated spirally formed As a result of the experiment, it was confirmed that no protrusion was formed on both side edges of the first metal coating 11a forming the coil.

First metal coating 11 forming this coil
The reason why no protrusion is formed on both side edges of “a” is considered as follows. That is, what directly affects the plating is the liquid layer (0.1 mm to 0.1 mm) in contact with the surface of the cathode (the electrode to be plated).
With a composition of 0.01 mm), the liquid layer in contact with the surface of the cathode is different from the plating liquid layer inside the plating tank 9. These differences significantly affect the impurity ions of the polymer system of dextrin and organic compound-based additives thio urea in.

It is considered that these additives are dispersed in a plating solution in a colloidal state and adhere to the cathode, thereby increasing the polarization of metal deposition. The growth of the electrodeposited metal crystal depends on the strength of the electric field at the interface of the plating solution of the cathode and the magnitude of the inhibitory action of the additive on the crystal growth. However, it is considered that when the action of the additive is strong, the growth in the direction of the line of electric force is suppressed.

In the first film forming step, sulfur S and chlorine Cl contained in the additive are deposited in the first metal film 11a during the deposition of the first metal film 11a. They are deposited together, and this deteriorates the corrosion resistance of the first metal coating 11a in the subsequent step of removing the resist 7 or coating the insulating layer.

Therefore, as shown in FIG. 1B, after the first metal film 11a is formed in the first film forming step, the first metal film 11a is formed in the first film forming step using the ordinary plating solution 10. The second metal film 11b is formed thinner than the metal film 11a. By forming a thin film of the normal second metal film 11b having good corrosion resistance on the coil-shaped first metal film 11a having no protrusions formed on both side edges as described above, the corrosion resistance in the next step is improved. Better.

As shown in FIG. 1C, the first and second metal films 11a and 11b form a coil 11
Is formed, the resist 7 and the underlying plating base 20 are removed by etching, and the coil 11 is covered with an insulating layer (not shown).

In the above-described coil forming method, when the (−) voltage is applied to the substrate 6 from the substrate power supply 14 and the (+) voltage is applied periodically for a predetermined time, the relationship between the current densities is increased. Thus, the effect of etching the metal film that has grown greatly on both side edges of the first metal film 11a works, and the effect of forming the both side edges of the first metal film 11a into a curved surface increases.

In the coil forming method, after the first metal film 11a for forming a coil is formed from the substrate power source 14, the first metal Apply a reverse current to the coating 11a,
If both side edges of the first metal film 11a are etched, the effect that the both side edges of the first metal film 11a are curved as described above is increased.

[0029]

According to the present invention, as described above, a substrate having a coil pattern formed on a substrate by a resist is placed in a plating solution in a plating tank, and a metal film is formed on the coil pattern between the resists by electroplating. in the method of forming a coil for a thin film magnetic head which is adapted by forming forming the coil, in the plating solution with the addition of thio urea dextrin and organic compound-based polymer systems between the resist performs electroplating After performing the first film-forming step of forming the first metal film on the coil pattern and the first film-forming step, the second thinner than the metal film formed by the first film-forming step with a normal plating solution. Since the second film-forming step of forming a metal film, and after performing the second film-forming step, a method of forming a coil for a thin-film magnetic head comprising a step of removing the resist of the coil pattern, The serial first film forming step, when forming a first metal film on the coil pattern between resist, additives added into the plating solution, i.e., a thio urea dextrin and organic compound-based polymer systems Due to the action, poor formation of the first metal coating that forms the coil,
That is, no protrusion is formed on both side edges of the first metal coating.

In the first film forming step, sulfur S and chlorine Cl contained in the additive are deposited in the first metal film when the first metal film is deposited. This deteriorates the corrosion resistance of the first metal coating in the subsequent resist removing step and the insulating layer coating step.

Therefore, by performing the second film-forming step, a normal thin second metal film having good corrosion resistance is formed on the first metal film having no projections formed on both side edges. By doing so, the corrosion resistance in the next step is improved.

Due to the effects described above, the formation of a metal film that forms a coil formed in a spiral shape,
That is, since no protrusion is formed on both side edges of the coil-shaped metal film, short-circuiting between the coils due to the protrusions formed on both side edges of the coil-shaped metal film unlike the related art is prevented.

[Brief description of the drawings]

FIG. 1 is a view showing each step of a method for forming a coil for a thin film magnetic head according to the present invention.

FIG. 2 is a schematic view of an electroplating apparatus for implementing a method of forming a coil for a thin film magnetic head according to the present invention.

FIG. 3 is a perspective view of a conventional general thin film magnetic head assembly.

FIG. 4 is an enlarged view of a conventional general thin film magnetic head.

FIG. 5 is a sectional view taken along line VV in FIG. 4;

FIG. 6 is a diagram in which a metal film is formed on a substrate by a conventional method.

FIG. 7 is a view in which a resist and a plating base thereunder are removed from the state of FIG. 6;

[Explanation of symbols]

 Reference Signs List 6 substrate 7 resist 8 coil pattern 9 plating tank 10 plating solution 11a first metal coating 11b second metal coating 11 coil 12 anode 13 auxiliary electrode 14 substrate power supply 15 auxiliary electrode power supply 16 management tank 17 pipe 18 pump 19 pipe 20 Plating base

Claims (1)

(57) [Claims] 1. A substrate (6) having a coil pattern (8) formed on a substrate (6) by a resist (7) is placed in a plating solution (10) in a plating tank (9), and the resist is formed by electroplating. (7) A method for forming a coil for a thin film magnetic head in which a coil is formed by forming a metal film on a coil pattern (8), wherein a polymer-based dextrin and an organic solvent are contained in a plating solution (10). a first film forming step of forming a first metal film (11a) on the coil pattern (8) between the resist (7) performs electroplating thio urea compound system by adding, first formed After performing the film process, the usual plating solution (10)
A second film forming step of forming a second metal film (11b) thinner than the metal film (11a) by the first film forming step, and a resist of a coil pattern after performing the second film forming step. (7) A method for forming a coil for a thin-film magnetic head, comprising the step of removing.