JP4826496B2 - Electrode plating anode electrode mounting structure - Google Patents

Description

  The present invention relates to an electrolytic plating anode electrode mounting structure provided in an electrolytic plating tank, and more particularly, to an anode electrode mounting structure that can effectively supply power to an anode electrode.

Conventionally, for example, when a thin film of copper (Cu) as a wiring material is formed on a semiconductor substrate of an LSI (semiconductor integrated circuit), an electrolytic plating method is employed (see Patent Document 1). In this electrolytic plating apparatus for forming a copper thin film, a cathode electrode is arranged at the upper part in the plating tank, and an anode electrode made of a copper electrode is arranged at the lower part in the plating tank.
The semiconductor substrate is provided so as to be connected to the cathode electrode and so that the surface of the conductive film formed on the semiconductor substrate is immersed in the electrolytic solution.

In the electrolytic plating apparatus having the above configuration, when a power source is connected between the cathode electrode and the anode electrode and energized, a copper thin film (plating film) is formed on the conductive film surface of the semiconductor substrate.
The material of the above-mentioned anode electrode is determined by the properties of the plating film. For this reason, when forming bumps, which are solder bump electrodes, on the semiconductor substrate by electrolytic plating, a solder alloy anode electrode is used.
As a structure for connecting a power source to the anode electrode, a metal electrode shaft connected to the power source is simply mounted on the metal power supply portion connected to the power source or a metal body forming the anode electrode body. Is known (see Patent Document 2).
JP 2006-219697 A JP 2005-503485 gazette

However, in the conventional anode electrode mounting structure, the one in which the anode electrode is placed on the metal power feeding part connected to the power source is easy to permeate the electrolyte between the power feeding part and the anode electrode. When the electrode penetrates, the portion of the anode electrode that contacts the power feeding portion is also eroded by electrolysis, increasing the plating voltage. As a result, there is a problem that plating cannot be performed before the anode electrode is used up.
In addition, the metal electrode shaft implanted in the metal body forming the anode electrode body must be manufactured with great care due to the low rigidity of the metal body. When contacting the plating tank wall, there is a problem in that the power supply to the anode electrode body is adversely affected and the anode electrode body is deformed.

  Therefore, the present invention has been made in view of the above circumstances, and the object thereof is to stably supply power to the anode electrode and to prevent the penetration of the electrolytic solution to improve the durability. Moreover, it is an object to provide an anode electrode mounting structure for electrolytic plating in which an anode electrode can be easily installed.

An anode electrode mounting structure for electrolytic plating according to the present invention includes a power supply plate having a protrusion on an upper surface, and an anode electrode placed in a state where the protrusion is bitten on the upper surface of the power supply plate. And
In the anode structure for electrolytic plating having the above structure, when the anode electrode is placed on the upper surface of the power feeding plate, the protrusion of the power feeding plate bites into the anode electrode, and the power feeding plate and the anode electrode are electrically integrated. The And the erosion by the contact of electrolyte solution is prevented in the biting-in part.

In the electrolytic plating anode electrode mounting structure according to the present invention, the protrusion may be provided in a ring shape on the upper surface of the power feeding plate.
The electrolytic plating anode electrode mounting structure having the above-described structure prevents the electrolyte from entering the region surrounded by the ring-shaped protrusions, thereby ensuring power supply.
Furthermore, in the anode electrode mounting structure for electrolytic plating according to the present invention, a plurality of the protrusions may be provided on the upper surface of the power supply plate in a dotted manner with a space between each other. By providing a plurality, the number of locations where these protrusions bite increases to a plurality, so that it is possible to more reliably prevent the electrolyte from entering.

In the electrolytic plating anode electrode mounting structure according to the present invention, a plurality of ring-shaped seal members having different diameters are provided between the power supply plate and the anode electrode, and the protrusions are disposed between the seal members. It is good also as the structure currently made.
The anode structure for electrolytic plating having the above-described structure is in a state in which the protruding portion of the power feeding plate that is bitten into the anode electrode is surrounded by the sealing member. It can be reliably isolated.

In the electrolytic plating anode electrode mounting structure according to the present invention, a liquid passage hole through which an electrolytic solution passes is provided at the center of the anode electrode.
In this case, since the protruding portion of the power feeding plate bites into the anode electrode, it is possible to reliably prevent the electrolyte from entering the biting portion even if the electrolytic solution is passed through the liquid passage hole.
In the electrolytic plating anode electrode mounting structure according to the present invention, if the power feeding plate is made of an insoluble electrode material and the anode electrode is made of a solder alloy, solder bumps can be formed by electroplating. In addition, since the anode electrode has low hardness, the protruding portion of the power feeding plate can be easily bited by its own weight or the like.

  According to the anode mounting structure for electrolytic plating according to the present invention, since the power feeding plate and the anode electrode are electrically integrated with the protruding portion of the power feeding plate biting into the anode electrode, the power feeding plate and the anode electrode It is possible to prevent the electrolyte from penetrating into the joint portion. Therefore, power can be stably supplied to the anode electrode, plating can be performed efficiently, and the anode electrode can be used up to the end. In addition, it is a simple structure in which the anode electrode is simply placed on the power supply plate, and the anode electrode can be easily installed.

Hereinafter, an embodiment of an anode electrode mounting structure for electrolytic plating according to the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing a schematic configuration of an electrolytic plating apparatus 1 to which an electrolytic plating anode electrode mounting structure according to a first embodiment of the present invention is applied.
The electrolytic plating apparatus 1 is provided with a cathode electrode 4 on which a semiconductor substrate 3 is mounted so as to be bridged over the plating tank 2 at the upper end of a plating tank 2 having a predetermined volume with an open top. A disk-shaped power supply plate 5 and a disk-shaped anode electrode 6 placed on the power supply plate 5 are provided in a stacked state in the lower part.

  The cathode electrode 4 is provided in a projecting shape at a plurality of locations on the upper end of the wall of the plating tank 2, and the semiconductor substrate 3 is mounted with a slight gap between the upper end of the cathode 4, thereby providing a plating tank. The plating surface of the semiconductor substrate 3 can be held in a state of being immersed on the liquid surface of the electrolytic solution L containing sulfuric acid or the like overflowing from 1.

  The power feeding plate 5 is made of insoluble electrode material such as titanium or titanium alloy having rigidity, platinum, or electrode material obtained by coating titanium or titanium alloy with platinum, and has a predetermined thickness so as not to be easily deformed. It is configured. A through hole 12 through which the liquid supply pipe 11 for supplying the electrolyte L is inserted is formed at the center of the power supply plate 5. Further, on the outer peripheral side of the upper surface of the power supply plate 5, a ring-shaped protrusion 13 having a tip formed at an acute angle is integrally formed.

  The anode electrode 6 has a planar shape that is the same as or larger than that of the power supply plate 5, but is made of a metal having a lower hardness than that of the power supply plate 5. It depends on the nature. For example, when the plating forms solder bumps on the semiconductor substrate 3, a solder alloy anode electrode is used. When a copper (Cu) thin film as a wiring material is formed on the semiconductor substrate 3, a copper alloy anode electrode is used. In addition, when the power supply plate is made of titanium or a titanium alloy, Sn, SnAg, SnAgCu, PbSn, and Pb can be used as the material for the anode electrode without any problem. A liquid passage hole 14 for allowing the electrolytic solution L to pass therethrough is formed at the center of the anode electrode 6 so as to face the liquid supply pipe 11 of the power supply plate 5.

Further, two ring-shaped seal members 15 and 16 having different diameters are provided between the power supply plate 5 and the anode electrode 6, and one of the seal members 15 is an upper surface of the power supply plate 5. The size of the sealing member 16 is determined so that it can be located outside the protrusion 13 provided on the other side, and the size of the other seal member 16 is determined so that it can be positioned inside the protrusion 13. That is, the protrusion 13 of the power feeding plate 5 is disposed between the seal members 15 and 16.
In FIG. 1, reference numeral 17 denotes an outer tank provided outside the plating tank 1 and is configured to receive the electrolyte L overflowing from the upper end wall of the plating tank 2. The electrolyte L received in the outer tank 17 is configured to be supplied from the lower part of the plating tank 2 through the liquid supply pipe 11.

  In the electrolytic plating apparatus 1 configured as described above, when the anode electrode 6 is placed on the power supply plate 5, the protrusion 13 of the power supply plate 5 bites into the back surface of the anode electrode 6 due to the weight of the anode electrode 6. As shown, the anode electrode 6 and the power feeding plate 5 are integrated at the top of the protrusion 13. Therefore, the penetration of the electrolytic solution L into the contact portion is prevented at the top of the protruding portion 13 that bites in.

In this case, since the anode electrode 6 is made of a solder alloy and has a hardness lower than that of the power feeding plate 5, the anode electrode 6 is simply placed on the power feeding plate 5 and is in a state of being bitten into the protrusion 13 of the power feeding plate 5. be able to.
And since the projection part 13 is in the state where the projection part 13 was surrounded by the two seal members 15 and 16 in the part which this projection part 13 bites in, the electrolyte solution L penetrate | invades between both the seal members 15 and 16. And the penetration of the electrolyte L can be effectively prevented.

  In the electrolytic plating apparatus 1 having such a configuration, the cathode of the power source E is connected to the cathode electrode 4, the anode of the power source E is connected to the anode electrode 6, and the electrolyte L is circulated from the liquid supply pipe 11 of the power feeding plate 5. When a current is applied between the electrodes 3 and 6, the thin plated film is formed on the surface of the semiconductor substrate 3 immersed in the electrolyte L. At this time, as described above, since the electrolytic solution L does not penetrate into the contact portion between the power feeding plate 5 and the anode electrode 6, power can be stably supplied to the anode electrode 6, and the semiconductor substrate 3 can be supplied with high quality. It can be plated with.

  On the other hand, FIGS. 3 and 4 show an anode electrode mounting structure according to the second embodiment of the present invention. In the power supply plate 21 in this embodiment, a plurality of protrusions 22 are provided in the form of dots spaced from each other, and at the inner peripheral portion and the outer peripheral portion between the power supply plate 21 and the anode electrode 6. Seal members 15 and 16 are provided, and each protrusion 22 is arranged in a region between the seal members 15 and 16. Other configurations are the same as the structure of the first embodiment described above.

  Also in such an electrode mounting structure, when the anode electrode 6 is placed on the power feeding plate 21, the protrusion 22 of the power feeding plate 21 bites into the back surface of the anode electrode 6 due to the weight of the anode electrode 6, and feeds power to the anode electrode 6. The plate 21 is integrated. Therefore, power can be stably supplied to the anode electrode 21. Moreover, since the part into which the protrusion part 22 bites is isolated from electrolyte solution by the two sealing members 15 and 16, penetration of electrolyte solution can be prevented effectively.

In addition, in the anode electrode mounting structure in both the above-described embodiments, the anode electrode 6 is simply placed on the power feeding plates 5, 21. However, if necessary, the anode electrode 6 is placed on the power feeding plates 5, 21. Alternatively, the anode electrode 6 may be slightly pressed from above so as to bite into the protrusions 13 and 22 of the power supply plate 5 by sandwiching the two using a clip mechanism or the like.
The present invention is not limited to the above-described embodiment, and can be changed without departing from the gist of the present invention. For example, two seal members are provided to seal the vicinity of the protrusions from the electrolyte, but three or more may be provided, and when the protrusions are arranged in a dotted shape, they are provided so as to surround each protrusion. May be. In addition, since the protruding portion has an effect of biting into the anode electrode and preventing permeation of the electrolytic solution, the sealing member can be omitted.

It is sectional drawing which shows schematic structure of the electroplating apparatus to which the anode electrode attachment structure which concerns on 1st embodiment of this invention is applied. FIG. 2 is an enlarged cross-sectional view of main parts of a power feeding plate and an anode electrode in FIG. It is sectional drawing of the electric power feeding plate and anode electrode in the anode electrode attachment structure which concerns on 2nd embodiment of this invention. FIG. 4 is an arrow view along the line AA in FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electroplating apparatus 2 Plating tank 3 Semiconductor substrate 4 Cathode electrode 5 Power supply plate 6 Anode electrode 11 Supply pipe 12 Through-hole 13 Protrusion part 14 Liquid passage hole 15,16 Seal member 17 Outer tank 21 Power supply plate 22 Protrusion part L Electrolyte E Power supply

Claims (6)

  An anode electrode mounting structure for electrolytic plating, comprising: a power supply plate having a protrusion on an upper surface; and an anode electrode placed in a state where the protrusion is bitten on the upper surface of the power supply plate.   2. The anode mounting structure for electrolytic plating according to claim 1, wherein the protrusion is provided in a ring shape on the upper surface of the power supply plate.   2. The anode mounting structure for electrolytic plating according to claim 1, wherein a plurality of the projecting portions are provided in a dotted shape on the upper surface of the power supply plate with a space between each other.   4. A plurality of ring-shaped seal members having different diameters are provided between the power supply plate and the anode electrode, and the protrusions are disposed between the seal members. An anode electrode mounting structure for electrolytic plating according to claim 1.   The anode electrode mounting structure for electrolytic plating according to any one of claims 1 to 4, wherein a liquid passage hole through which an electrolytic solution passes is provided in a central portion of the anode electrode.   6. The anode mounting structure for electrolytic plating according to claim 1, wherein the power feeding plate is made of an insoluble electrode material, and the anode electrode is made of a solder alloy.

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