WO2002079548A1

WO2002079548A1 - Electrolytic plating tank

Info

Publication number: WO2002079548A1
Application number: PCT/JP2001/002603
Authority: WO
Inventors: Souichi Obata
Original assignee: Fujitsu Limited
Priority date: 2001-03-28
Filing date: 2001-03-28
Publication date: 2002-10-10
Also published as: JPWO2002079548A1; JP3924537B2

Abstract

An electrolytic plating tank capable of applying a plating of uniform thickness, characterized by comprising a first tank (21) having an anode (22) disposed therein and being enclosed, a second tank (24) provided adjacent to the first tank (21) and having a cathode (25) disposed therein, a pump (26) for force-feeding plating liquid to the first tank (21), and a nozzle (30) installed in a partition wall (31) located between the first tank (21) and the second tank (24), formed of a number of tubular bodies (32) having a specified length and positioned parallel with each other, feeding the plating liquid fed to the first tank (21) to the second tank (24) through the tubular bodies (32), and causing a liquid flow in the plating liquid contained in the second tank (24).

Description

Specification

Technical field of electroplating bath

The present invention relates to an electroplating bath, and more particularly, to an electroplating bath capable of performing plating with a uniform thickness and controlling the plating thickness. Background art

FIG. 23 is a schematic diagram showing the most common plating tank 10.

1 2 is the anode and 1 3 is the power sword. The plating solution is circulated and filtered by a circulating filter (not shown). 14 is an outlet for the plating solution, and the plating solution is supplied in the direction of the arrow. A shielding plate 15 may be inserted between the anode 12 and the force sword 13. The shielding plate 15 has a large number of through holes 16 (black circles in the figure) as shown in FIG.

To stir the plating solution, as shown in FIG. 25, a lining pipe 17 is provided in the lower part of the tank.

FIG. 26 shows another type of apparatus, a jet-type plating apparatus.

In the case of this plating apparatus, the plating solution is ejected from the plating solution ejection pipe 18 provided in the vertical direction toward the object held by the force source 13 to apply plating to the object. I am trying to apply. The anode (not shown) is formed in a net shape or a ring shape, and is attached inside the tip of the ejection pipe 18. This jet-type plating device is of an open system, that is, it jets the plating solution into the air.

In the case of the electrolytic plating tank shown in FIG. 23, the plating solution flows upward along the side wall of the plating tank, and flows from behind the anode 12 toward the center of the tank 10. However, there is a problem that the plating solution has a low flow rate with respect to the object to be plated, and the plating flow tends to be non-uniform because the flow of the solution is not uniform. For this purpose, air ration is often performed as shown in Fig. 25.However, due to the difference in liquid pressure, the situation differs between the upper and lower parts of the tank, and uniform agitation cannot be performed. The problem is that it is not possible to obtain You. In addition, air easily accumulates in the recesses of the object to be covered, causing problems such as no attachment.

In addition, when a shielding plate 15 as shown in FIG. 24 is used, the porosity is about 20%, so that there is a problem that the flow resistance of the solution is large, and the plating speed and plating efficiency are reduced. Furthermore, the purpose of using the shielding plate 15 is to control the lines of electric force. I can't get it. If the diameter of the through hole 16 is reduced, the electric flux lines can be prevented from wrapping around, but the plating efficiency will be significantly reduced.

In the case of the jet-type plating apparatus shown in Fig. 26, since it is an open system, a shielding plate cannot be used, and it is difficult to control the film thickness. Furthermore, it is suitable for partial plating but not suitable for plating large areas.

Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an electrolytic plating tank capable of plating with a uniform thickness and controlling the plating thickness. .

Further, the present invention is to provide an electrolytic plating bath which can control lines of electric force, can perform plating of a uniform thickness, and can reduce the size of the apparatus.

In order to solve the above-mentioned problems, an electrolytic plating tank according to the present invention is provided with a first tank in which an anode is disposed and sealed, and is provided adjacent to the first tank, and is internally provided. A second tank in which a force sword is arranged; a pump for pumping the liquid attached to the first tank; and a plurality of parallel tanks provided on a partition wall between the first tank and the second tank. A nozzle comprising a cylindrical body having a required length of a book, wherein the plating solution sent to the first tank is sent through the cylindrical body to the second tank, and a liquid flow is generated in the plating solution of the second tank. And characterized in that:

Since the plating solution is fed into the second tank from a large number of cylinders, it is possible to prevent the electric power lines from wrapping around and obtain a plating film having a uniform thickness. Also, the plating thickness can be controlled by changing the diameter, length, number, arrangement, etc. of the cylinders. Further, a structure in which the anode can be passed from one surface of the first tank facing the partition wall facing the partition wall to the other surface opposite to the one surface. It is preferable that the plating solution be sent between the opposed wall surface and the anode by the pump.

As a result, the plating solution flows in the closed first tank from behind the anode while contacting the anode, so that the ion concentration increases and the amount of ions supplied per unit time can be increased. The plating speed is improved.

Further, an ejection unit into which a plating solution is sent from the pump is disposed between the opposed wall surface and the anode, and the ejection unit includes a plurality of ejection pipes. It is characterized in that a number of small holes for ejecting the liquid toward the opposed wall surface are provided.

By arranging such a jet unit, a uniform turbulent state is generated in the entire tank, and the contact efficiency with the anode is further increased.

In addition, since the stirring efficiency is increased, there is no need for an air rate, and problems such as non-sticking can be eliminated.

It is preferable that a partition wall provided with the nozzle be provided detachably. This is suitable because it is possible to select and install various types of nozzles whose diameter, length, number and arrangement are changed in accordance with the properties of the covering object.

Further, the electrolytic plating tank according to the present invention has a plurality of rods between the anode and the force sword, and the electric lines of force are bent by passing the lines of electric force between the rods, In this case, a shielding means for lengthening the path of the lines of electric force is provided.

As a result, the lines of electric force reaching the force sword become almost parallel, and a uniform plating film can be obtained. It is also effective for plating in blind vias. In addition, the size of the device can be reduced accordingly.

When a plurality of the rods are provided and each rod in each row is positioned between the rods in the adjacent rows, the lines of electric force meander and the path of the lines of electric force can be lengthened. BRIEF DESCRIPTION OF THE FIGURES Fig. 1 is a plan view of the plating tank with the cover removed, Fig. 2 is a front view of the nozzle, Fig. 3 is a front view of the blowout unit, and Fig. 4 is a diffusion double layer. FIG. 5 is an explanatory view showing the effect of suppressing the wraparound of the lines of electric force by the cylinder, FIG. 6 is a front view of the first tank, and FIG. 7 is a plan view of the first tank. Yes, FIG. 8 is a side view of the first tank, FIG. 9 is a front view of the first tank in the embodiment, FIG. 10 is a plan view of FIG. 9, and FIG. 9 is a side view of FIG. 9, FIG. 12 is a front view of a first tank in still another embodiment, FIG. 13 is a plan view of FIG. 12, and FIG. FIG. 15 is a side view of FIG. 12, FIG. 15 is a front view of a first tank in still another embodiment, FIG. 16 is a plan view of FIG. 15, and FIG. Fig. 15 Side view FIG. 18 is an explanatory view showing a plating thickness measuring point of an adherend, FIG. 19 is a plan view of a plating tank showing still another embodiment, and FIG. FIG. 21 is a front view of the unit, FIG. 21 is an explanatory view showing the arrangement of the rods of the shielding unit, FIG. 22 is an explanatory view showing the meandering state of the electric flux lines, and FIG. FIG. 24 is an explanatory view of a conventional general electrolytic plating tank. FIG. 24 is a front view of a shielding plate, and FIG. 25 is an explanatory view of a state in which an air pipe is provided. FIG. 6 is an explanatory view of a jet-type plating apparatus, and FIG. 27 is an explanatory view showing a wraparound state of lines of electric force when a shielding plate is used. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic plan view of the electrolytic plating tank 20.

Reference numeral 21 denotes a sealed first tank (chamber 1) in which a plurality of anodes 22 extending vertically are arranged. The plating solution can flow between the front and back of the anode 22 through the gap between the adjacent anodes 22.

The anodes 22 are connected by a connection bar (not shown) and connected to a power supply device (not shown).

The first tank 21 can be hermetically closed by a lid (not shown).

A second tank 24 is provided adjacent to the first tank 21 (horizontally in the horizontal direction). A force sword 25 is disposed in the second tank 24. Casio The node 25 is connected to a power supply device (not shown).

The plating solution in the second tank 24 is pumped into the first tank 21 through a pipe 27 by a circulation pump 26. This feeding flow rate is appropriately changed depending on the size of the tank.

Reference numeral 30 denotes a nozzle, which is provided on a partition wall 31 between the first tank 21 and the second tank 24, and is composed of a plurality of parallel cylindrical bodies 32 having a required length. With this nozzle 30, the plating solution sent to the first tank 21 is sent to the second tank 24 through the cylindrical body 32, and the plating solution flows into the plating solution of the second tank 24. Cause.

FIG. 2 shows an example of the arrangement of the cylindrical body 32.

The partition wall 31 is provided detachably with respect to the tank, and is replaced with various nozzles 30 in which the diameter, length, number, arrangement, etc. of the cylindrical bodies 32 are changed according to the type of the object to be covered. It is preferable to be able to do so.

Although the plating solution may be simply pumped into the first tank 21 by the pump 26, the plating solution may be ejected into the first tank 21 through the ejection unit 33 as shown in FIG. This is preferable.

The blow-out unit 33 is disposed between the opposed wall surface 21 a of the first tank 21 opposed to the partition wall 31 and the anode 22.

The blowout unit 33 includes a plurality of blowout pipes 35 each having both ends connected to the communication pipe 34. The plating solution is directed to the blowout pipe 35 toward the facing wall surface 21a. A large number of small holes 36 erupting almost vertically are provided.

Next, the operation of the electrolytic plating tank 20 will be described.

The liquid gushing out of the jetting unit 33 is vigorously jetted toward the opposing wall 21a, hits the opposing wall 21a and is agitated, and becomes turbulent. Since the small holes 36 of the jetting unit 33 are provided substantially uniformly distributed, the state of the liquid flow becomes almost the same everywhere, and the liquid passes between the anodes 22. Thus, the plating solution is introduced into the second tank 24 through the cylindrical body 32 after passing through the gap between the anodes 22 arranged in the sealed first tank 21. As a result, a uniform ion flow with a high ion concentration is obtained. The plating efficiency is improved, and a plating film having a uniform film thickness can be obtained.

FIG. 4 is an explanatory diagram of a diffusion double layer near the anode 22 surface. As shown in the figure, the positive ions are almost positive in the immediate vicinity of the anode 22, but the negative ions increase as the distance from the anode 22 increases. Becomes This unbalanced region of charge is called a diffusion double layer.

The thinner the diffusion double layer, the smoother the supply of ions, and therefore the faster the plating rate and the more uniform the film pressure.

In the present embodiment, since the plating solution in a uniform flow state contacts the anode 22 from behind the anode 22 at a uniform and high speed and passes, the diffusion double layer becomes thinner, and the plating efficiency is improved. In addition, a uniform film pressure can be obtained.

Further, as shown in FIG. 5, the plating solution passes through the cylinder 32 of the nozzle 30. By arranging the cylindrical body 32 in this manner, the lines of electric force are interrupted, the degree of the lines of electric force wrapping behind the partition wall 31 is reduced, and the shielding effect is increased. Therefore, it is not necessary to forcefully reduce the opening area (diameter of the cylinder), and the shielding effect can be increased without lowering the plating efficiency. Further, the plating solution is supplied to the object to be covered at a certain flow rate through the cylindrical body 32. This also makes it possible to improve the plating speed and obtain a plating film having a uniform film pressure.

FIG. 6 (front view), FIG. 7 (plan view), and FIG. 8 (side view) show an example of the arrangement and length of the cylinder 32. In this example, the cylinders 32 are arranged uniformly on the partition wall 31 and have the same length.

FIG. 9 (front view), FIG. 10 (plan view), and FIG. 11 (side view) show another example of the arrangement and length of the cylinder 32. In this example, the length of the cylinder 32 located in the center area of the partition wall 31 is made longer than the length of the peripheral cylinder 32. By doing so, it is possible to increase the plating thickness at the center of the covering object. -Fig. 12 (front view), Fig. 13 (plan view), and Fig. 14 (side view) show another example of the arrangement and length of the cylinder 32. In this example, the upper, middle, and lower cylinders 32 are set to be longer in this order. In this example, with power source 25 In the vicinity (near the corner of the second tank 24), the flow rate of the plating solution increases toward the lower side (the upper side decreases the flow rate of the plating solution due to the liquid resistance). The liquid flows upward from below near the wall surface. Therefore, garbage that easily stays near the corner of the second tank 24 can be rolled up and sent to a filtration device to be removed. In general, the thickness of the plating on the lower side of the object to be covered tends to be small. However, according to this example, the object to be covered can be plated with a uniform thickness.

The partition wall 31 is detachably provided in the tank (for example, so that it can be pulled upward from the first tank 21), and FIG. 6 to FIG. 8, FIG. 9 to FIG. 11, FIG. The optimal plating thickness can be obtained according to the shape and the like of the object to be covered by selecting and mounting the partition wall 31 in which the cylindrical bodies 32 are arranged as shown in FIG. That is, the plating thickness can be controlled.

FIG. 15 (front view), FIG. 16 (plan view), and FIG. 17 (side view) show still another example of the nozzle 30. In this example, a shielding plate (not shown) having holes arranged in an appropriate arrangement is arranged inside the partition wall 31 so as to block the entrance of the cylindrical body 32 at a required portion (FIG. 1). (The thick black circle of 5 indicates a closed cylinder.) Alternatively, the hole diameter of the cylinder 32 can be adjusted by reducing the hole diameter of the shielding plate.

The thickness of the plating can be easily controlled with the ones in Fig. 15 to Fig. 17.

An experimental setup for the setup shown in Fig. 1 was created and the plating thickness was measured.

The overall size was 100 mm square in Fig. 1 and the depth was 90 mm. The position of the partition plate 31 was about 40 mm from the opposite wall surface. The thickness of the partition plate 31 was 2 mm, and the length of the cylinder 32 was 2 mm. Therefore, the actual length of the cylinder 32 is 4 mm. The inner diameter of the cylinder 32 was 5 mm. The inner diameter of the jet pipe 35 was 8 mm, and the diameter of the small hole 36 was 1 mm. The pump 26 pumped the plating solution at a rate of 3 liters per minute to the first tank 21. The liquid depth in the second tank 24 was 60 mm.

The composition of the plating solution is shown below. Proper value

Sulfuric acid (98%) 180 260g / 1 220g / 1

Copper sulfate5 water 60 ^ 80 g / 1 70 g / 1

Chloride ion 30 80ppm 50ppra

Current density 1 3 A / d 2 A / d

Temperature 20 30 ° C 25 ° C Example 1 in Table 1 shows the distribution of plating thickness when electrolytic copper plating was performed with the above-mentioned appropriate amount of plating solution composition. Figure 18 shows the measurement points for the plating thickness of the adherend. table 1

In the conventional example, a completely common copper plating tank shown in Fig. 23 was used (the size of the plating tank was almost the same as the experimental apparatus).

As is clear from Table 1, it can be seen that the plating thickness of Example 1 is more uniform than that of the conventional example.

FIG. 19 shows an electrolytic plating bath 40 according to still another embodiment.

In the present embodiment, a shielding unit (shielding means) 41 capable of controlling the line of electric force (lengthening the path of the line of electric force) is disposed between the anode 22 and the force source 25.

As shown in Fig. 20, this obstruction unit 4Ί A plurality of rods 43 extending in the vertical direction are fixed to 42.42.

An example of the arrangement of the rods 43 is shown in FIG.

In this example, in a mounting tank with a distance of about 100 mm between the anodes 22, a connecting plate 42 with a width of about 20 mm and a round rod 4 3 made of PVC with a diameter of about 1 mm in 15 rows. They were arranged in a staggered pattern. That is, each rod 43 in each row was located between the rods 43 in the adjacent row. In the above case, the interval between the round bars 43 is about 1 mm.

By doing so, as shown in FIG. 22, the lines of electric force travel while avoiding the rod-shaped body 43 which is an insulator, so that the path of the lines of electric force becomes longer. Calculations have shown that the insertion of the shielding unit 41 in the tank of the above size increases the path of the lines of electric force between the anode 22 and the cathode 25 by about 10% < In general, as the distance between the electrodes increases or as the solution resistance of the plating solution increases, the lines of electric force become parallel, and a uniform plating thickness can be obtained. However, increasing the distance between the electrodes increases the size of the plating tank. The liquid resistance of the plating solution is regulated by the plating solution composition and can hardly be adjusted.

In this regard, in the present embodiment, by using the shielding unit 41, it is possible to lengthen the path of the electric flux lines by a plating tank of the same size, thereby obtaining a uniform plating thickness. be able to. Also, the size of the plating tank can be reduced accordingly.

In addition, in the shielding plate as shown in FIG. 24, the aperture ratio is about 20%, and the problem that the resistance to the flow of the liquid is large has already been described. Since the rods 43 are only present in parallel at intervals, the aperture ratio is practically 100%, and has little effect on the plating efficiency.

The results of measuring the plating thickness with the above experimental apparatus are shown in Example 2 of Table 1 above. The plating solution used was an electrolytic copper plating solution having the above composition.

As is clear from Example 2, a plating film having a more uniform thickness than the conventional example was obtained.

In the above embodiment, the rod-shaped body 43 of the shielding unit 41 is parallel to the vertical direction. Although it is arranged so as to extend, it may be arranged so as to extend parallel to the lateral direction. Further, it is needless to say that the conditions such as the arrangement, the number, and the diameter of the rods 43 can be appropriately changed according to the plating conditions of the covering object or the like.

If the shielding unit 41 is arranged in front of the nozzle 30 shown in FIG. 1 and the like, a more uniform plating thickness can be expected. The invention's effect

According to the first aspect, since the plating solution is sent from the large number of cylinders to the second tank, it is possible to prevent the electric flux lines from wrapping around, and to obtain a plating film having a uniform thickness.

Also, the plating thickness can be controlled by changing the diameter, length, number, arrangement, etc. of the cylinders.

According to claim 2, since the plating solution flows in the closed first tank from behind the anode while contacting the anode, the ion concentration increases, and the amount of ions supplied per unit time increases. The plating speed is improved.

According to the third aspect, by disposing the ejection unit, a uniform turbulent state is generated in the entire tank, and the contact efficiency with the anode is further increased.

According to claim 4, various types of nozzles whose diameter, length, number, and arrangement are changed according to the properties of the covering object can be selected and mounted, which is preferable.

According to the fifth aspect, the lines of electric force reaching the force sword are almost parallel, and a uniform plating film can be obtained. It is also effective for plating in blind vias.

In addition, the size of the device can be reduced accordingly.

According to the sixth aspect, the lines of electric force meander, and the path of the lines of electric force can be lengthened.

Claims

The scope of the claims

1. A first tank in which an anode is placed and sealed,

A second tank provided adjacent to the first tank and having a force sword disposed therein;

A pump for pumping the liquid attached to the first tank;

It is provided on a partition wall between the first tank and the second tank, and is composed of a large number of parallel cylinders having a required length, and the plating solution fed into the first tank is passed through the cylinder. A nozzle that feeds into the second tank and generates a liquid flow in the plating liquid in the second tank.

2. The anode has a structure in which a plating solution can flow from one surface facing the opposite wall surface of the first tank facing the partition wall to the other surface opposite to the one surface. Formed in

The electrolytic plating tank according to claim 1, wherein the pump sends a plating solution between the opposed wall surface and the anode.

3. An ejection unit, into which the plating solution is sent from the pump, is disposed between the opposed wall surface and the anode, and the ejection unit includes a plurality of ejection pipes, 3. The electrolytic plating tank according to claim 2, further comprising a plurality of small holes for jetting a plating solution toward the opposed wall surface.

4. The electrolytic plating tank according to claim 1, wherein a partition wall provided with the nozzle is detachably provided.

5. A shielding means having a plurality of rods between the anode and the force sword, wherein the lines of electric force pass between the rods to bend the lines of electric force, thereby lengthening the path of the lines of electric force. An electroplating bath characterized by being provided with:

6. The electrolytic plating tank according to claim 5, wherein a plurality of the rods are provided, and each rod in each row is located between the rods in an adjacent row.