JPS60158611A - Plating device - Google Patents

Abstract

PURPOSE:To obtain a plated film having no variation of the composition of the plated film, and to indicate favorably magnetic anisotropy by a method wherein a substrate to form the plated film thereon is rotated, and a magnetic field having the fixed direction always is applied on the substrate according to the magnetic field to rotate synchronizing with the rotation of the substrate. CONSTITUTION:A substrate holder 13 is connected to a rotary shaft 12 in a plating tank 11, and a substrate 14 to be plated is held by the substrate holder 13. Permanent magnets 15 to apply magnetic anisotropy to the substrate 14 are held by the substrate holder 13, and a plating current is flowed between an anode 16 and the substrate 14 rotating the rotary shaft 12 according to a rotation driving body such as a motir, etc. to form a plated film on the surface of the substrate 14.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a plating apparatus for plating a magnetic film, and in particular,
The present invention relates to a plating apparatus characterized in that a plating solution is constantly stirred by rotating a substrate on which a plating film is formed, and plating is performed while always applying a magnetic field in a fixed direction onto the substrate.

[Background of the invention]

Conventionally, when plating various metal films or alloy films on electronic components, etc., it is known that stirring of the solution on the surface of the plating during plating is an important factor in the properties of the plating film. , stirring of the plating solution by air bubbles in the plating tank,
Stirring has been carried out by mechanically moving a stirrer.

In particular, when it comes to alloy plating for electronic components, where the composition of the plating film must be precisely controlled, it is known that the stirring method and the state of stirring of the plating solution have a large effect on the alloy composition of the plating film. Various efforts have also been made. For example, A, bstrat A 287
．． A plating device called Extended AbStrHCtS dollar type has been reported. According to this method, the current density flowing through the mating electrodes is always uniform on average, and it can be applied to many types of electronic components such as All,
It has been shown that various metals or alloys such as pe-Ni and pe-Ni-Cu are formed. However, in the case of this device, the plating solution is stirred by moving the paddle near the substrate to be plated, so as the paddle moves, new solution is supplied onto the substrate to be plated, and plating It has been stated that diffusion of metal ions occurs, resulting in periodic fluctuations in the plating current.

When plating an alloy film, the composition of the plated film changes when the plating current changes. Therefore, it is necessary to perform plating while keeping the plating current constant. To this end, a stirring method is required that allows the stirring state of the plating solution near the substrate to be plated in the plating solution to not change over time, that is, to maintain a steady state.

[Object of the Invention] When plating a magnetic film such as a Fe-Ni alloy film, an object of the present invention is to apply a directional magnetic field to the substrate to be plated, and to apply a directional magnetic field to the substrate to be plated. An object of the present invention is to provide a plating apparatus for obtaining a plating film exhibiting good magnetic anisotropy without fluctuations in the composition of the plating film by keeping the agitation state of the plating solution in a steady state.

[Summary of the invention]

The plating apparatus of the present invention is characterized by plating while rotating the substrate on which the plating film is to be formed in the plating solution, thereby maintaining the solution state on the substrate surface in a steady state.
That is, by creating a hydrodynamic boundary layer on the substrate surface with a constant thickness throughout the substrate plane, changes in the plating current over time due to intermittent renewal of new solution to the substrate surface are prevented, and the The current distribution of the plating current is made uniform, the plating current is kept constant, and a magnetic field is always applied in a constant direction to the rotating substrate.

[Embodiments of the invention]

Hereinafter, the present invention will be explained using the drawings.

Figure 1 shows an example in which the part that forms the magnetic field to be applied to the substrate rotates in the same direction as the rotation of the board, and a permanent magnet is used as the part that applies the magnetic field to the board. It was there. A substrate holder 13 is connected to a rotating shaft 12 within the plating bath 11 . Further, the substrate 14 to be fitted into the substrate holder 13 is held, and a permanent magnet 1 is still attached to the substrate 14 in order to add magnetic anisotropy to the substrate 14.
5 is held in one set by a substrate holder 13.

In this substrate holder 13, a rotating shaft 12 held by a bearing 17 is driven by a rotational drive body such as a motor (not shown), and smoothly rotates in the plating solution. Further, an anode 16 is installed in a portion of the plating tank 11 facing the substrate 14, and by passing a plating current between the anode 16 and the substrate 14, the substrate 14 is
Form a plating film on the surface.

With this configuration, stirring of the plating liquid on the surface of the substrate 14 does not change over time, and a constant current can be passed at all times, and a uniform composition and uniform magnetic anisotropy can be imparted. It is possible to form a prickly film.

FIG. 2 shows the arrangement of the substrate 14 and the permanent magnets 15 when the substrate holder 13 is viewed from the surface to be plated. In this case, it is desirable that the surface of the substrate holder 13 on the side on which the substrate 14 is attached is as smooth as possible. This is because when the surface is extremely uneven, when the substrate holder 13 is rotated, the flow of the plating solution is obstructed by the unevenness, creating a local turbulent flow state and changing the thickness of the boundary layer. This is because it becomes impossible to obtain a uniform current density distribution within the plane of the substrate.

FIG. 3 shows a cross-sectional view of the substrate holder 13. As shown in FIG.

As mentioned above, the mating surface of the board holder 13 needs to be smooth, so it is recommended that the permanent magnet 15 be embedded in the board holder 13 on the opposite side from the mating surface of the board holder 13. . In addition, the method for holding the substrate 14 is to make electrical contact with the surface of the substrate 14, and if only the entire surface of the substrate 14 is plated, current concentration will occur at the edge of the plated film on the surface of the substrate 14. In order to make the film thickness and composition uniform, by plating an area larger than the surface of the substrate 14, current concentration at the edge of the surface of the substrate 14 is prevented and the current distribution within the surface of the substrate 14 is made constant. It is recommended to use a substrate holder 131 made of a metal plate, for example, stainless steel. The height of the brim of this substrate holding part 131 is the difference in level between the substrate 14 and the substrate holder 13, so in order to make the flow of liquid uniform, it is better to make it as small as possible, and it is recommended that the height of the brim be 0.2 rtarr or less. It is desirable to do so. Further, the substrate holder 13 other than the substrate holding part 131 is made of an insulator, for example, a fluororesin. However, in order to make the current density distribution uniform in the plane of the substrate, it is also possible to change the ratio of the size of the simultaneous plating part that is the substrate holding part 131 and the area of the insulator part 132 of the substrate holder 13. be. In addition, the plating part, including the substrate surface and the substrate holder, has a disk shape centered on the rotation center of the substrate holder, which allows for uniform flow of the plating solution and uniform current density distribution within the substrate surface. It is particularly effective. 13
3 is a rubber seal), and 134 is a block that presses the board 14.

FIG. 4, FIG. 5, and FIG. 6 show the arrangement of substrates and permanent magnets when two substrates are plated at the same time. Fifth
In the case shown in the figure, since the distance between the pair of permanent magnets 15 is large, a strong magnet is required to apply a sufficient magnetic field onto the substrate 14. On the other hand, in FIG. 6, the distance between the permanent magnets 15 is half that of FIG. 5, so the strength of the permanent magnets 15 may be the same as that of applying a magnetic field to one substrate.

Regarding the arrangement shown in Figure 4 and the arrangement shown in Figures 5 and 6, the flow direction of the plating solution is almost tangential to the rotation, so it is necessary to match the direction of the magnetic field application and the micropattern. In the case of electronic components, the direction of liquid flow can be selected depending on the micropattern.

Similarly, it is also possible to hold three or more substrates.

Furthermore, although the above explanation is based on the case where permanent magnets are used, this is also possible using electromagnets in the same way.

Above, we have shown a substrate holder that holds the substrate together with a magnet (permanent magnet or electromagnet) that provides a magnetic field to be applied in the plane, but the part that forms the magnetic field to be applied to the substrate is Another embodiment of the method in which the magnetic field is applied to the substrate by rotating the same as in FIG. 7 is shown in FIG. The substrate holder 73 rotates while holding the substrate 75 in the blood. This is the same as the embodiment of FIG. The applied magnetic field is applied to a permanent magnet holder 7 arranged around the outer periphery of the plating tank 71 and connected to a rotating shaft 72.
7 and is always applied in a fixed direction to the substrate by fc1 set of permanent magnets 74. The feature of this method is that only the board 75 to be fitted into the board holder 73 needs to be held, so if the size of the board holder 73 is the same and the number of boards is the same, the method shown in FIG. The point is that it can also be made smaller. Furthermore, if the size of the substrate holder is the same, the number of substrates can be increased. However, since it is necessary to install a permanent magnet 74 for applying a magnetic field outside the plating tank 71 and to rotate the permanent magnet 74 simultaneously with the rotation of the substrate 75, the structure of the entire plating apparatus is rotatable. The portions are larger, so it is larger.

Even in this case, not only a permanent magnet but also an electromagnet can be used to apply the magnet.

Next, the part that forms the magnetic field applied to the substrate does not move;
FIG. 8 shows an embodiment in which plating is performed while only the magnetic field applied to the substrate rotates in the same manner as the rotation of the substrate. This structure is roughly divided into a substrate rotating plating section and a rotating magnetic field applying section using an electromagnet 85. By rotating the magnetic field applied by the electromagnet 85 in synchronization with the rotation of the substrate 840, a magnetic field in the same direction can always be applied to the substrate 84.

A substrate holder 83 holding a substrate 84 to be plated is connected to a rotating shaft 82 and installed in the plating tank 81 . Further, an electromagnetic coil 85 for applying a rotating magnetic field is installed outside the plating tank 81, and it detects the rotational position of the substrate 84 using a rotational position detector 87 installed on the rotating shaft 82. At the same time, the electromagnet power supply 88
An electric signal is applied to the substrate 84, and plating is performed while a constant magnetic field is always applied to the substrate 84 by the electromagnet 85.

According to this method, only the substrates need to be held in the substrate holder portion, so the size of the substrate holder can be reduced as long as the number of substrates remains the same.

Further, since the magnetic field is a rotating magnetic field generated by a fixed electromagnetic coil, there is no need for a movable part such as a driving part for rotating the magnet, and the structure of the 6D plating apparatus is simplified.

Although the substrate holder in the mating tank shown in each of the above embodiments has a structure in which the substrate surface is horizontal and faces downward, it can be made horizontal and facing upward, or it can be vertical.

It is also possible to have a structure inclined with respect to the horizontal plane, and it is possible to obtain an optimal structure depending on the plating conditions and the uniformity of the plating film composition.

〔Effect of the invention〕

As explained above, according to the plating apparatus of the present invention, a plated film having a uniform composition and good magnetic anisotropy can always be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of the plating apparatus of the present invention, Fig. 2 is a schematic diagram showing the positional relationship between a substrate holder, a substrate, and a magnet, and Fig. 3 is a schematic diagram showing the structure of the substrate holder. Figure 4,
5 and 6 are schematic diagrams showing the positional relationship between the substrate holder, the substrate, and the magnet, and FIGS. 7 and 8 are schematic diagrams showing other embodiments of the present invention. 11... Plating tank, 13... Substrate holder, 14...
・Board, Figure 11, Figure 2 Figure/3 Figure 13, Figure 32 ■Figure 4 A, Figure 7, Figure 3

Claims (1)

[Claims] 1. A plating tank that stores a plating solution, a substrate holder that supports a substrate on which a plating film is to be formed and rotates the substrate during plating within the plating tank, and a substrate holder that supports the substrate on which a plating film is to be formed and rotates the substrate during plating, and A plating device comprising means for applying a magnetic field. 2. The plating apparatus according to claim 1, wherein the means for applying a magnetic field to the substrate is a permanent magnet that rotates in synchronization with the substrate. 3. The plating apparatus according to claim 1, wherein the means for applying a magnetic field to the substrate is an electromagnet that is arranged along the rotational direction of the substrate and generates a rotating magnetic field in synchronization with the rotation of the substrate. .