JP2001020097A - Plating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve particularly the distribution of plated film thickness and to shorten the lead time to form desired plated film thickness in a plating device for plating in a pattern like form on one surface of a wafer by an electroplating method. SOLUTION: A material to be plated is arranged as a cathode in an electroplating liquid 2 in a plating vessel 1 to face an anode 6, a shielding member 9 keeping a desired interval from the anode surface and having an opening part 10 at the central part is arranged on the outer periphery of the anode surface of the opposed surface side to the cathode, the max. dimension of the opening part is set to equal to or below the max. dimension of a region on the cathode surface, where the plating to be patterned is existed, and the max. dimension of the wetted surface 6a to the electroplating liquid on the anode surface is made larger than the max. dimension of a region on the cathode surface, where plating to be patterned is existed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating apparatus for performing plating in a pattern on a wafer surface by an electrolytic plating method, and more particularly to an improvement in a plating film thickness distribution and an improvement in a time required until a desired plating film thickness is formed. About.

[0002]

2. Description of the Related Art FIG. 6 is a diagram showing a configuration of a conventional plating apparatus. In the figure, a plating tank 1 is filled with an electrolytic plating solution 2, and a wafer 3 to be plated is held therein by a holding member 4 a, 4 b made of an insulating material as a cathode, and placed therein. A disk-shaped anode 6 held by a conductive pillar 5 is provided facing the electrode at a predetermined interval. A conductor (not shown) is provided in the holding member 4a, and a power source is supplied from the wafer 3.
The current path to 7 is secured. A current is supplied from a power source 7 to form a plating film on the surface of the wafer 3. For the plating film, a pattern to be plated is formed on the wafer surface with a photoresist or the like, and only that portion is plated.

In the above-described conventional plating apparatus, there is a problem that the plating film thickness at the outer peripheral portion of the wafer is larger than that at the central portion of the wafer. This is because the current density at the outer peripheral portion of the wafer is higher than that at the central portion of the wafer.

In order to solve such a problem, conventionally,
Although not shown, the outer peripheral portion of the anode surface on the side facing the wafer is shielded with an insulating material, and the wetted surface of the anode with the electrolytic plating solution has a small area only at the center opening, and the outer periphery of the wafer from the anode is removed. The aim was to make the plating film uniform by increasing the distance to the portion and reducing the current density at the outer peripheral portion of the wafer. Although this method is an effective means for making the plating film thickness uniform, the time required to form the desired plating film thickness is greatly extended because the area of the anode wetted with the electrolytic plating solution is small. There was a problem of saying.

[0005]

As described above, in the prior art, the problem that the plating film thickness at the outer peripheral portion of the wafer is larger than that at the central portion of the wafer, and the problem is to solve this problem. Then, there is a problem that the time required for forming a desired plating film thickness is greatly extended. The present invention solves such a problem, makes the plating film thickness distribution on the wafer surface more uniform, and at the same time reduces the time required to form a desired plating film thickness, which is shorter than the time required by the conventional technology. It is intended to provide a device.

[0006]

According to a first aspect of the present invention, there is provided a plating apparatus for performing plating in a pattern on a wafer surface of an object to be plated by an electrolytic plating method. In the electroplating solution, the object to be plated is disposed as a cathode, facing the anode, and a required space is maintained between the anode surface and the outer periphery of the anode surface facing the cathode, and an opening is formed in the center. The maximum dimension of the opening is set to be equal to or less than the maximum dimension of the area where the pattern plating is present on the cathode surface, and the maximum dimension of the wet surface of the anode surface with the electrolytic plating solution is set. The size of the region on the cathode surface where the pattern plating exists is larger than the maximum size. With this configuration, when a current flows from the wetted surface of the anode with the electrolytic plating solution toward the pattern plating on the wafer surface, the current from the anode wetted surface at the rear of the shielding member passes through the opening. Therefore, the current flows to the pattern plating on the wafer surface, and the current path becomes longer than that of the related art. This means that the electrical resistance increases as the current path becomes longer, the current value decreases, the current density at the outer peripheral portion of the wafer becomes lower than in the prior art, and the plating film thickness becomes more uniform. Furthermore, if the area of the anode wetted surface is set to be the same as that of the conventional technique, the amount of Ni ions dissolved in the electrolytic plating solution from the wetted surface does not change. When the plating film thickness is made more uniform, the Ni deposited on the entire pattern-plated portion when the plating film thickness at the central portion of the wafer is the same as that of the conventional example, as compared with the conventional example.
Becomes smaller. This means that the total volume of Ni laminated on all the pattern plating parts is determined by the product of the current value supplied from the power supply and the plating time. It means that less is needed. That is, it is possible to reduce the time required to form a desired plating film thickness to be shorter than the time required in the conventional technique.

According to a second aspect of the present invention, there is provided a plating apparatus according to the first aspect, further comprising: an anode holder surrounding a surface of the disk-shaped anode other than a surface facing the cathode. A shielding member having a circular outer shape is disposed on the side facing the cathode, and the anode is sandwiched between the anode holder and the shielding member. With this configuration, the anode holder, anode, and shielding member are integrated, so when replacing or cleaning the anode, remove the anode from the plating tank in this integrated state and replace the anode or remove impurities. After performing the cleaning work, the work for integration can be performed again and locked to the plating tank.

According to a third aspect of the present invention, there is provided a plating apparatus as set forth in the second aspect, wherein a filter cloth having a fine pore diameter is arranged over the entire surface so as to surround the anode. And an anode holder and / or an anode and a shielding member to sandwich the filter cloth. With such a configuration, the anode surrounded by the filter cloth is replaced with the anode in the configuration of claim 2, so that a special member for holding the filter cloth is not required. .

In order to achieve the above object, a plating apparatus according to a fourth aspect is characterized in that, in the plating apparatus according to the second or third aspect, an air vent hole is provided in the shielding member or the shielding member and the anode holder. It was done. With this configuration, when the electrolytic plating solution is injected into the plating tank, the air remaining between the anode and the shielding member can be released to the outside through the air vent hole.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG.
This will be described with reference to FIG. FIG. 1 is a diagram showing a configuration of a plating apparatus according to a first embodiment of the present invention. The configuration of the plating apparatus in the figure is an example of a step of performing Ni plating with a plating film thickness of 100 μm in a process of manufacturing a magnetic head slider for a magnetic disk on a silicon wafer surface. In the figure, a plating tank 1 contains an electrolytic plating solution.
2 is a plastic tank that can store about 5 liters up to the liquid level 2a. As the electrolytic plating solution 2, a nickel sulfamate plating solution is used. The wafer 3 to be plated has a material of silicon, a diameter of 100 mm and a thickness of 0.5 mm, and functions as a cathode in electrolytic plating. The wafer 3 is sandwiched by holding members 4 a and 4 b made of vinyl chloride as an insulating material, and is disposed in the plating tank 1. A conductor (not shown) is provided in the holding member 4a, and thereby a current path from the wafer 3 to the power supply 7 is secured.

The anode 6 is composed of an anode holder 8 which is made of Ni containing sulfur, has a diameter of 120 mm and a thickness of 5 mm and surrounds a surface other than the surface facing the wafer 3, and a surface side facing the wafer 3. The anode 6 is interposed between the anode 6 and a shielding member 9 having an opening 10 at the center while maintaining an interval of about 5 mm between the anode 6 and the anode 6. In order to maintain this sandwiching state, the screw member 11 is screwed into the screw portion 8 a of the anode holder 8, and sandwiches the anode 6 via the shielding member 9. Here, the anode holder 8, the shielding member 9, and the screw member 11 are all made of insulating vinyl chloride. The support 5 is screwed with the anode 6, and the anode 6 and the wafer 3 are about 50m in length.
It is locked to the plating tank 1 so as to face each other with an interval of m. The material of the support 5 is made of conductive stainless steel, and its surface is plated with Ti so that components of the stainless steel do not dissolve and flow into the electrolytic plating solution 2.

FIG. 4 is a view taken in the direction of arrow A in FIG. In the figure, the area surrounded by the dotted line of the wafer 3 indicates the area 16 where the pattern plating 15 exists, and the diagonal length 17 indicates the maximum dimension of the area 16 where the pattern plating 15 exists. I have.

FIG. 5 is a view taken in the direction of arrows BB in FIG. In the figure, the outer shape of the shielding member 9 is circular, and the shape of the opening 10 provided in the center of the shielding member 9 is circular, and further, the outer shape of the anode 6 is circular, This indicates that the wetted surface 6a of the anode 6 with the electrolytic plating solution 2 is also circular.

The electrolytic plating solution 2 in the plating tank 1 is circulated while filtering impurities by a pump (not shown).

Here, the dimensional relationship of the main parts of the plating apparatus having the structure shown in FIGS. 1, 4 and 5 is summarized as follows: X is the maximum dimension (17) of the region 16 where the pattern plating 15 exists.
When the maximum dimension of the opening 10 of the shielding member 9 is Y, and the maximum dimension of the wetted surface 6a of the anode 6 with the electrolytic plating solution 2 is Z, the following relations are set. X ≧ Y, X <Z Next, the operation of the plating apparatus having the configuration shown in FIGS. 1, 4 and 5 will be described. When a voltage is applied between the anode 6 and the wafer 3 serving as a cathode by the power supply 7, the electrolytic plating solution of the anode 6 is applied.
Pattern plating on wafer 3 from wet surface 6a with 2
Electric current flows toward 15, and at the same time, Ni ions dissolve in the electrolytic plating solution 2 from the wet surface 6a. On the other hand, Ni is deposited on the pattern plating 15 on the surface of the wafer 3 and is laminated and N
An i-plated film is formed. Here, what is different from the conventional technique is that when a current flows from the wetted surface 6a toward the pattern plating 15 on the surface of the wafer 3, the current from the wetted surface 6a of the shadow portion (rear portion) of the shielding member 9 is This is to flow through the opening 10 to the pattern plating 15 on the surface of the wafer 3. This means that the current path from the wetted surface 6a at the rear of the shielding member 9 to the pattern plating 15 on the surface of the wafer 3 is longer than that of the conventional technology, and that the current path is longer. However, since the electric resistance increases by that amount, the current value decreases, and as a result, the current density at the outer peripheral portion of the wafer 3 becomes lower than that of the conventional technology, and a plurality of coatings on the surface of the wafer 3 are formed. It is possible to make the plating thickness distribution of the pattern plating 15 more uniform. Furthermore, if the area of the wetted surface 6a of the anode 6 is set to be the same as the area of the surface of the conventional anode 6 facing the wafer 3 in FIG. 6, N which dissolves in the electrolytic plating solution 2 from the wetted surface 6a can be obtained.
The amount of i-ions does not change. Where all pattern plating
The total volume of Ni stacked on 15 is determined by the product of the current value supplied from the power supply 7 and the plating time. According to the present embodiment, when the plating film thickness distribution of the pattern plating 15 is made more uniform, when the plating film thickness at the central portion of the wafer 3 is set to be the same as that of the conventional example as compared with the conventional example, the layers are stacked. The total volume of Ni becomes smaller. This means that if the current value supplied from the power supply 7 is constant, the plating time is short. That is, the time required to form a desired plating film thickness in the present invention can be made shorter than the time required in the conventional technique.

FIG. 2 is a diagram showing a configuration of a plating apparatus according to a second embodiment of the present invention. In FIG.
The filter cloth 14 is arranged so as to surround the filter cloth. This is the anode
In this embodiment, a non-woven polypropylene fabric or a PTFE (polytetrafluoroethylene) membrane having a fine pore diameter is used as the material. However, the shape is not a bag-shaped one, but simply a cloth-shaped one. As a means for holding the cloth-like filter cloth 14 on the anode 6, the filter cloth 14 is held between the anode 6 and the anode holder 8 and between the anode 6 and the shielding member 9 and held on the anode 6 side as shown in the figure. .

In FIG. 1, an anode holder 8 and a shielding member
Air vent hole 13 near the level 2a of electrolytic plating solution 2
And 12 are provided respectively. This is to replace the electrolytic plating solution 2 at a predetermined cycle, but to prevent air from remaining in the lower part of the air vent hole 12 when the electrolytic plating solution 2 is injected into the plating tank 1.

FIG. 3 is a diagram showing a configuration of a plating apparatus according to a third embodiment of the present invention. In this figure, the difference from FIGS. 1 and 2 is that the screw member 11 is not present.
In order for the shielding member 9 to have the function of the screw member 11, a screw that is screwed into the screw portion of the anode holder 8 is provided on the outer periphery of the shielding member 9. This structure is effective when the shape of the opening 10 is circular and the phase of the opening 10 is the same regardless of the final fixing position of the shielding member 9. Another different point is the position of the air vent hole 12. Air vent hole
By providing a plurality of 12 on a concentric circle, the shielding member 9
No matter where the final fixing position is, the air vent hole 12 functions.

The plating thickness distribution in the above-described embodiment of the present invention is such that the variation width is about 20 μm in the case of the prior art, while the variation width is about 20 μm with respect to the target plating thickness of 100 μm. It was about 10 μm, which could be reduced to 50% of that of the conventional technology. In addition, the time required for plating at that time was 190 minutes in the case of the conventional technology,
This was reduced to 165 minutes, an improvement of about 13%.

In the above embodiment of the present invention, it is assumed that the shape of the opening is circular. However, the present invention may be applied to a shape similar to the shape of the region where the pattern plating exists on the wafer surface. Is valid. In this case, it is desirable that the openings having similar shapes have a phase relationship so as to be a mirror image of the shape of the region where the pattern plating exists. Further, in the above-described embodiment of the present invention, a soluble anode is used as the anode, but the present invention is effective even if the anode is an insoluble anode. Further, the present invention is effective not only for a silicon material but also for a ceramic, a glass and the like.

[0021]

Since the present invention is constructed as described above, it has the following effects.

According to the first aspect of the present invention, it is possible to make the plating thickness distribution of a plurality of patterns to be plated on the wafer surface more uniform, and furthermore, to form the plating thickness desired in the present invention. The required time can be made shorter than the required time in the related art.

According to the second aspect of the present invention, since the anode holder, the anode and the shielding member are integrated, when the anode is replaced or cleaned, the anode is removed from the plating tank in this integrated state, and the anode is replaced or replaced. After performing the cleaning work for removing impurities, the work for integration is again performed to lock the inside of the plating tank. Therefore, various operations can be performed not in a narrow plating tank but in a wide space outside the plating tank, so that operation efficiency is improved and high-quality operations can be performed.

According to the third aspect of the present invention, since the filter cloth is sandwiched between the anode and the anode holder and / or between the anode and the shielding member, a cloth-like filter cloth can be used. Since no special member is required, the operating cost of the plating apparatus and the cost of the plating apparatus can be reduced.

According to the fourth aspect of the present invention, by providing the air vent hole, air can be vented from the shielding member, and the time required for plating can be extended due to a decrease in the wetted surface area of the anode generated when air stays. In addition, it is possible to prevent an increase in variation in plating film thickness due to an imbalance in the vertical direction of the amount of generated Ni ions.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a plating apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a plating apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a plating apparatus according to a third embodiment of the present invention.

FIG. 4 is a view taken in the direction of arrow A in FIG. 1;

FIG. 5 is a view taken along the line BB in FIG. 1;

FIG. 6 is a diagram showing a configuration of a plating apparatus as a conventional example.

[Explanation of symbols]

1 ・ ・ ・ ・ ・ Plating tank 2 ・ ・ ・ ・ ・ ・ ・ Electroplating solution 2a ・ ・ ・ ・ ・ ・ ・ Liquid level 3 ・ ・ ・ ・ ・ Wafer 4a, 4b ・ ・ ・ Holding member 5 ・ ・ ・ ・ ・ ・ ・ Pole 6 ・ ・... Anode 6a ... Wet surface 7 ... Power supply 8 ... Anode holder 8a ... Screw 9 ... Shielding member 10 ... Opening Part 11: Screw member 12, 13: Air vent hole 14: Filter cloth 15: Patterned plating 16: Area where patterned plating is present 17: ... Maximum dimension of area where pattern plating exists

Claims (4)

[Claims] 1. A plating apparatus for plating an object to be plated in a pattern on a wafer surface by an electrolytic plating method, wherein the object to be plated is disposed as a cathode in an electroplating solution in a plating tank so as to face an anode. A required distance is maintained between the anode and the anode on the outer surface of the anode facing the cathode, and a shielding member having an opening in the center is arranged. It is set to be equal to or less than the maximum dimension of the area where plating exists, and the maximum dimension of the wetted surface of the anode surface with the electrolytic plating solution is larger than the maximum size of the area where the pattern plating exists on the cathode surface. And plating equipment. 2. The plating apparatus according to claim 1, wherein an anode having a circular outer shape surrounds a surface other than a surface facing the cathode, and a shielding member having a circular outer shape is formed of a cathode. A plating apparatus, which is disposed on an opposite surface side and sandwiches an anode between an anode holder and a shielding member. 3. The plating apparatus according to claim 2, wherein a filter cloth having a fine pore diameter over the entire surface is disposed so as to surround the anode, and the filter cloth is filtered with the anode and the anode holder and / or the anode and the shielding member. A plating apparatus characterized by being sandwiched. 4. The plating apparatus according to claim 2, wherein an air vent hole is provided in the shielding member or the shielding member and the anode holder.