JPH0754189A - Electroplating device - Google Patents

Abstract

PURPOSE:To provide the electroplating device capable of suppressing the fluctuation in the compsn. of plating films on a substrate to be plated and forming magnetic films having excellent magnetic characteristics. CONSTITUTION:This electroplating device has a plating tank 1, a substrate holder 11 which holds the substrate 4 to be plated mounted in the plating tank 1 in a holding part, an auxiliary electrode 12 which is disposed within or around the substrate holder 11 concentrically with the mounting part, an anode 5 which is disposed in the plating tank 1 to face with the substrate holder 11, a pair of prism-shaped stirrers which are disposed above and below in such a manner that the plane parts on respective one side moving back and forth near the surface of the substrate 4 to be plated are almost paralleled with the substrate 4 to be plated, magnets 10 which are capable of impressing magnetic fields in a direction parallel with the surface to be plated and a direction orthogonal with the direction where the stirrers move back and forth and are disposed in parallel on both sides of the plating tank 1 and a pair of upright arms 7 which fix both ends of the stirrers 13, 14 at both ends. The stirrers 13, 14 are disposed in >=2 on a pair of the upright arms 7 in almost parallel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroplating apparatus suitable for applying a magnetic thin film having excellent magnetic properties to a substrate to be plated used in a magnetic head, a recording head or the like.

[0002]

2. Description of the Related Art In recent years, electroplating methods have been used to obtain high-performance magnetic thin films.

As an electroplating device, Japanese Patent Publication No. Sho 57-96
The one proposed in Japanese Patent Publication No. 36 has been put into practical use and is being widely used.

A conventional electroplating apparatus will be described below. FIG. 8 is a perspective view of a main part of a plating tank of a conventional electroplating apparatus. Reference numeral 1 is a plating tank made of a dielectric material such as glass or synthetic resin in which a plating solution is injected, 2 is a cathode attached to the bottom of the plating tank 1, 3 is an opening formed in a predetermined portion of the cathode 2, Reference numeral 4 denotes a substrate to be plated, which is adhered by pressing the plating surface side to the outside of the opening 3, and 5 is made of inactive Pt, solid Ni or an inactive Pt sheet and an Ni wire mesh, which are arranged to face the cathode 2. An anode made of a combination or the like, 6 is a pair of stirrers in which the flat surface of each side of the triangular prism is vertically arranged substantially parallel to the upper surface of the substrate holder so as to suppress the generation of turbulent flow at the time of driving. An upright arm that fixes a pair of stirrers 6 in parallel at both ends, 8 is a lateral member that fixes two upright arms 7, and 9 is one end fixed to the center of the lateral member and the other end is a crankshaft (not shown). Link member 10 directly connected to the shaft of the electric motor (not shown) via A pair of magnets disposed on both sides of the plating tank 1 so as to apply a magnetic field in a direction perpendicular to the direction of movement of the child 6.

The operation of the plating apparatus constructed as above will be described below. During electroplating, the electric motor rotates and the crankshaft causes the link member 9 to reciprocate back and forth. This reciprocating motion is the reciprocating motion of the stirrer 6, and the plating solution passing through the opening surface between the pair of stirrers 6 becomes a laminar flow with little turbulence near the cathode 2. Due to this laminar flow, a uniform plated film can be obtained on the substrate 4 to be plated. Uniaxial magnetic anisotropy is imparted to the plated film by the magnet 10.

[0006]

However, in the above-mentioned conventional structure, the stirrer 6 reciprocates near the surface of the substrate 4 to be plated.
There is a problem that the above plating efficiency changes, the lines of electric force are cut off at the position of the stirring bar 6, and the current density during plating changes. As a result, the composition of the formed plating film such as the Fe—Ni alloy changes due to the change in the current density on the substrate to be plated 4, and it is difficult to obtain a uniform plating film.

The present invention solves the above-mentioned conventional problems, and provides an electroplating apparatus capable of forming a magnetic film having excellent magnetic characteristics while suppressing variations in the composition of the plated film on the substrate to be plated. It is an object.

[0008]

In order to achieve this object, an electroplating apparatus according to the present invention comprises a plating tank, a substrate holder for holding a substrate to be plated mounted in the plating tank at a mounting portion, and An auxiliary electrode disposed in or around the substrate holder concentrically with the mounting portion of the substrate to be plated, an anode installed in the plating tank facing the substrate holder, A pair of triangular prism-shaped stirrers arranged vertically so that the flat surface of each side reciprocating near the plated surface of the plated substrate is substantially parallel to the plated substrate, and the plated substrate of the plated substrate A magnet that is parallel to the surface and is disposed in parallel with the plating tank sandwiching the plating tank that can apply a magnetic field in a direction orthogonal to the direction in which the stirrer reciprocates, and a pair of upright arms that fix the stirrer at both ends. Electroplating equipment with There are, has a structure in which the stirrer is arranged in the pair of upstanding arms substantially parallel 2 or more.

[0009]

With this configuration, since there are a plurality of pairs of the first stirrer and the second stirrer, even if the width of one side parallel to the substrate to be plated is narrowed, the same or more stirring effect can be obtained as compared with the conventional case. However, since the width of one side is narrow, the change in current density during electroplating can be suppressed. Since the change of the current density is suppressed, the composition of the Fe-Ni alloy plating film can be made uniform. Moreover, the film thickness of the plating film can be made uniform.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall schematic configuration diagram of an electroplating apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view of a main part of a stirring bar portion of the electroplating apparatus.

Reference numeral 1 is a plating tank, 4 is a substrate to be plated, 5 is an anode, 7 is an upright arm, 8 is a lateral member, 9 is a link member, and 10 is a magnet. These are the same as in the conventional example of FIG. Therefore, the same numbers are attached and the description is omitted. Reference numeral 11 denotes a substrate holder arranged at the bottom of the plating tank 1, 12 denotes auxiliary electrodes arranged concentrically around the mounting portion of the substrate 4 to be plated, 13,
Reference numeral 14 denotes a pair of agitators in which the flat surface of each side of a triangular prism whose both ends are fixed to the upright arms 7 and 7 are arranged in parallel vertically with the plating surface of the plated substrate 4 mounted on the substrate holder 11. The stirrer 15 is a stirrer including stirrers 13 and 14 and the upright arm 7. The stirrer 15 reciprocates in a direction indicated by an arrow a. Reference numeral 16 is a current-carrying portion for powering the substrate 4 to be plated
7 is a plating solution tank for storing the plating solution and adjusting the concentration of the plating solution; 18 is a circulation path of the plating solution;
Is a supply pump that circulates the plating solution in the plating solution tank 17 to the plating tank 1, 20 is a filter having a passage hole of 0.1 to 1 μm for filtering impurities and the like in the plating solution, 21
Is a supply pipe for supplying the plating solution to the plating tank 1, and 22 is a return pipe for returning the plating solution in the plating tank 1 to the plating solution tank 17.

In FIG. 2, a pair of stirrers 13 and 14 of the stirrer 15 are each formed of a solid or hollow triangular prism, and are arranged so that their ridge lines are parallel to each other in the same direction. ing.

The operation of the plating apparatus of this embodiment having the above structure will be described below with reference to the drawings. FIG. 3 is a schematic view of the plating part of the electroplating device of the present invention.

The plated surface of the substrate 4 to be plated is fixed to the substrate holder 11 with the plating surface side facing the anode 5. The electrode is electrically connected from the plated surface side of the substrate 4 to be plated through a conductive rubber (not shown) to serve as a cathode. Electrolytic plating is performed by applying a voltage between the anode 5 and the substrate 4 to be plated that serves as the cathode. In order to establish electrical continuity between the substrate 4 to be plated and a conductive rubber (not shown), permalloy (Fe-N) was previously formed on the surface of the substrate 4 to be plated.
i alloy) must be attached by a sputtering method or a vapor deposition method.

Next, permalloy (Fe having excellent magnetic characteristics)
-Ni alloy) shows the preferable plating conditions for obtaining a plated film.

(I) Preparation of plating solution NiSO ₄ .6H ₂ O 250-350 g / l, NiC
l ₂ · 6H ₂ O to 40~60g / l, H ₃ BO ₄ 20
~ 30 g / l, 0.5% sodium sulfobenzimide
To 2.0 g / l, the FeSO ₄ · 6H ₂ O 10~20g
/ L, 0.1-0.5g / l sodium lauryl sulfate
Then, sulfuric acid is added so that the pH becomes 2.2 to 3.0.

The plating conditions are such that the flow rate of the plating solution is 7 to 2
0 l / min, plating current density of ² to 20 mA / cm ² ,
The paddle speed is preferably 30 to 400 mm / sec, the temperature of the plating solution is 28 to 43 ° C., and Ti, Pt, Ni or the like is preferably used for the anode 5.

Every time the stirrers 13 and 14 of the stirrer 15 move left and right on the substrate 4 to be plated, OH ⁻ and Fe ₂ + (O _{2) in the} vicinity of the substrate 4 to be plated reacted by plating.
H) ₂ , H + H ₂ etc. are scraped up by the lower stirrers of the stirrers 13 and 14 as shown by the arrow b, and fresh plating solution is supplied from each upper stirrer to the plated substrate 4 side as shown by the arrow c. To do. Further, the lines of electric force are easily concentrated on the peripheral portion of the substrate to be plated 4, and the Ni composition and the film thickness are likely to vary. However, the auxiliary electrode 12 is concentric with the substrate to be plated 4 around the substrate to be plated 4. , A voltage is applied between the anode 5 and the auxiliary electrode 12 to prevent the lines of electric force from concentrating on the peripheral portion of the substrate 4 to be plated, and to suppress fluctuations in Ni composition and film thickness. be able to.

By making these stirrers 13 and 14 compact and arranging a plurality of them in parallel, the liquid near the substrate 4 to be plated can form an ideal laminar flow state when moving near the substrate 4 to be plated. As a result, the concentration of metal ions can be made uniform.

Experimental Example 1 Next, the plating efficiency was evaluated using the electroplating apparatus of this example. The evaluation method was performed by measuring the current density under the conditions for producing a plated film of permalloy (Fe-Ni alloy). The results are shown in Fig. 4. FIG. 4 is a time-dependent change diagram of current density during plating in the electroplating apparatus of this embodiment.

Preparation of plating solution NiSO ₄ .6H ₂ O 320 g / l, NiCl ₂ .6
50 g / l of H ₂ O, 30 g / l of H ₃ BO ₄ , 1.5 g / l of sodium sulfobenzimide, FeSO ₄ ·
6H ₂ O at 15 g / l and sodium lauryl sulfate at 0.
A plating solution of 2 g / l was prepared.

Plating conditions While adjusting the pH of the plating solution to 2.5 to 2.6, a substrate sputtered with permalloy was used, the flow rate of the plating solution was 12 l / min, and the plating current density was 3.8 mA. / Cm ² , the reciprocating speed of the stirrer is 60 mm /
sec, the temperature of the plating solution was set to 30 to 35 ° C., and Ni was used for the anode 5.

(Comparative Example) A plating solution was prepared under the same conditions as in the experimental example except that the conventional electroplating device was used in place of the electroplating device of this example, and the permalloy plating film was formed under the same plating conditions. The current density was measured under the manufacturing conditions. The results are shown in Fig. 5.

FIG. 5 is a time-dependent change diagram of current density during plating in the conventional electroplating apparatus.

As is apparent from FIGS. 4 and 5, it was found that according to this embodiment, the change in current density can be suppressed by 35% or more as compared with the conventional example.

This is schematically shown as follows. FIG. 6 is a state diagram of electric lines of force between the anode 5 and the substrate in this experimental example, and FIG. 7 is a state diagram of electric lines of force between the anode 5 and the substrate in the plating apparatus of the comparative example. As is clear from FIG. 6, in the present experimental example, the stirrers 13 and 14 are divided into about 1/2 and are smaller than the conventional stirrer, so that the lines of electric force and the stirrer 13 are agitated. It can be said that the current also flows between the children 14, and as a result, the fluctuation of the current density is suppressed.

[0028]

As described above, according to the present invention, since a plurality of pairs of stirring bars are used, the shape of the stirring bars can be made small and the fluctuation of the current density can be suppressed. By arranging multiple stirrers with small shapes in parallel, the stirring efficiency of the plating solution can be significantly improved. As a result, the film quality is extremely excellent, and stable magnetic properties with suppressed macro and micro distributions within the substrate are achieved. It is possible to realize an electroplating apparatus capable of applying a film.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram of an electroplating apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part of a stirrer part of an electroplating apparatus according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of a plating part of the electroplating device of the present invention.

FIG. 4 is a diagram showing a change with time in current density during plating in the electroplating apparatus according to the present embodiment.

FIG. 5 is a diagram showing changes with time in current density during plating in a conventional electroplating apparatus.

FIG. 6 is a state diagram of lines of electric force between the anode and the substrate in this experimental example.

FIG. 7 is a state diagram of electric lines of force between an anode and a substrate in a plating apparatus of a comparative example.

FIG. 8 is a perspective view of a main part of a plating tank of a conventional electroplating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plating tank 2 Cathode 3 Opening part 4 Substrate to be plated 5 Anode 6 Stirrer 7 Upright arm 8 Horizontal member 9 Link material 10 Magnet 11 Board holder 12 Auxiliary electrode 13,14 Stirrer 15 Stirring part 16 Current-carrying part 17 Plating liquid tank 18 Circulation flow path 19 Supply pump 20 Filter 21 Supply pipe 22 Return pipe

Claims (1)

[Claims] 1. A plating tank, a substrate holder for holding a substrate to be plated mounted in the plating tank at a mounting portion, and a concentric circle with the mounting portion of the substrate to be plated in or inside the substrate holder. Auxiliary electrodes arranged around,
The anode installed in the plating tank facing the substrate holder and the flat surface of each side reciprocating in the vicinity of the plated surface of the plated substrate are substantially parallel to the plated substrate. A pair of upper and lower triangular stirrers are parallel to the plated surface of the substrate to be plated and sandwich the plating tank capable of applying a magnetic field in a direction orthogonal to the reciprocating direction of the stirrer. What is claimed is: 1. An electroplating apparatus comprising: a magnet provided; and a pair of upright arms that fix the stirrer at both ends, wherein the stirrer is disposed on the pair of upright arms substantially parallel to each other. An electroplating device characterized in that