JP2006009050A - Etching method and etching apparatus for cathode electrode device in plating equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To safely and efficiently remove a plating film formed on an electrode assembly in a cathode electrode device used in plating equipment for a wafer or a substrate. <P>SOLUTION: The subject etching apparatus 2 is used for an electrode 15 provided on the other end of a cathode holder 11 composed of a cylindrical body 111 and having a first projection 113 extending to the outside almost vertically to the axis of the cylindrical body 111 along at least a part of the outer circumferential part of one end of the cylindrical body 111, and forming the cathode of the plating equipment and is provided with an etching vessel 20 provided with a bottom board 23, a side wall 21 extending almost vertically to the bottom board 23 and also around the surface of the bottom board 23, and a second projection 22 extending to the inside along at least a part of the tip of the side wall 21, and having an opening into which the cylindrical body 111 can be inserted. The side wall 21 has a height to produce a gap X between the electrode 15 and the bottom board 23 at the time when the first projection 113 is placed on the second projection 22 in a direction where the electrode 15 and the bottom board 23 are confronted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plating apparatus, and more particularly to an etching method and an etching apparatus for a cathode electrode device used in a plating apparatus for a wafer or a substrate.

As one of the thin film formation technologies used in the manufacture of thin film magnetic heads and other various electronic components, electroplating is mainly used for the formation of Cu films, etc. Has been. For example, when forming a Cu film by plating, for example, a conductive film is generally formed on a substrate surface by a PVD (Physical Vapor Deposition) method or the like, and a thin base material of Cu is formed thereon by PVD or CVD ( It is formed by the Chemical Vapor Deposition) method, and an electrode is attached thereto and Cu plating is performed. When positive Cu ions reach the cathode substrate, an electrochemical reaction of Cu ⁺⁺ + 2e → Cu occurs on the substrate surface, and Cu is deposited on the substrate surface to form a Cu thin film.

  Conventionally, when performing such electroplating, an anode as an anode is installed in a plating tank, and the object to be plated is fixed at a predetermined position facing the anode while being held by a wafer holder, and a cathode electrode device is attached to the object to be plated. Was attached to form a cathode.

  FIG. 5 shows an example of an overall configuration diagram of a plating apparatus of a face-up type, that is, a type in which a cathode electrode device is mounted from below the conventional plating apparatus and is opposed to the anode. The plating tank 31 has a space in which a plating solution 32 can be put. The plating tank 31 includes a plating solution supply line 33 for supplying a plating solution 32 from a reservoir tank (not shown), a return line 34 for returning the plating solution 32 to the reservoir tank, and the plating solution 32 so as not to exceed a predetermined liquid level. And an overflow line 35. In the plating tank 31, an anode 36 is suspended and fixed and held by a support tube 37 that penetrates the top plate of the plating tank 31. The anode 36 is connected to the positive side of the power supply device 38 through a support tube 37.

  A frame 39 having a substantially circular opening 40 is provided at the bottom of the plating tank 31 facing the anode 36, and the cathode electrode device 1 is supported by the frame 39 along the periphery of the opening 40. Is provided. The cathode electrode device 1 has an opening 18 and is connected to the negative side of the power supply device 38. An object 41 to be plated, such as a wafer or a substrate, is supported by the wafer holder 43 from below the opening 18 with the surface 42 to be plated facing the inside of the plating tank 31 and loaded into the cathode electrode device 1. Then, the outer periphery of the plated surface 42 comes into contact with the cathode electrode device 1, and a predetermined potential state of the cathode is formed on the plated surface 42. The object to be plated 41 is fixed to the cathode electrode device 1 in this state.

  FIG. 6 shows a schematic cross-sectional view of the cathode electrode device. The cathode electrode device 1 includes a cathode holder 11 and an electrode supported by the cathode holder 11. The cathode holder 11 has a substantially cylindrical side wall 111 as a main structural portion, a stepped portion 112 on the side of the inner end 111a of the side wall 111 facing the inner space of the plating tank 31, and a side of the opposite outer end 111b. The 1st flange 113 is formed in this. On the step portion 112, the first electrode 12, the packing 13, the spacer 14, and the second electrode 15 are placed in this order toward the inner end portion 111a. These are all (hereinafter referred to as an electrode assembly). Is fixed to the cathode holder 11 by a fastener 16 inserted from the inner end 111a toward the outer end 111b. The first electrode 12, the packing 13, the spacer 14, and the second electrode 15 all have a disk-like shape having a hole in the center. When these are assembled, the opening 18 (see FIG. 5) is formed.

  The object to be plated 41 is fixed so as to be in contact with the back surface of the first electrode 12 when viewed from the internal space of the plating tank 31. In addition, a lead conductor 17 is connected to the first electrode 12, and the first electrode 12 is connected to the power supply device 38 (see FIG. 5) via the lead conductor 17. Thus, the 1st electrode 12 fulfill | performs the function which supplies the electric potential of a cathode directly to the to-be-plated object 41. FIG. The packing 13 is an elastic body (for example, rubber) having insulating properties, and tightly fixes the electrode assembly. The spacer 14 is similarly insulative, but a harder material is used to maintain uniform deformation of the packing 13 and to place the electrode assembly straight with respect to the cathode holder 11. The second electrode 15 is provided for controlling the film thickness and film thickness distribution of the plating film formed on the object to be plated 41 by forming a plating film on the electrode. The electrode 12 is electrically connected.

  The first flange 113 of the cathode holder 11 constitutes a mating portion with the frame 39 for attachment to the plating tank 31. On one surface of the first flange 113, there is provided a groove 114 for mounting an O-ring 115 for preventing liquid leakage when the plating solution 32 is filled in the plating tank 31. The first flange 113 does not need to have a flange shape in which protrusions are formed along the entire circumference of the side wall 111 as long as the sealing performance is ensured. A protrusion extending outward at a substantially right angle may be used.

  When plating is performed using the plating apparatus 31 having such a configuration, a plating film is also formed on the second electrode 15 that is in the cathode potential state and that faces the anode 36, and the tip of the fastener 16 is also formed. Covered with plating film. On the other hand, the first electrode 12, the second electrode 15 and the packing 13 are consumables and therefore need to be periodically replaced. For this purpose, the cathode holder 11 is removed from the plating tank 31 and then the electrode assembly is removed. It needs to be disassembled. However, since the tip of the fastener 16 is covered with the plating film, the fastener 16 cannot be loosened as it is. For this reason, conventionally, an etching chemical such as nitric acid is dropped onto the second electrode 15 with the second electrode 15 side of the cathode holder 11 as the upper surface, and the plating film covering the fastener 16 is removed.

  However, such a working method of directly dropping a powerful drug such as nitric acid has a problem in terms of work safety such as etching chemicals may be scattered and be applied to workers. Further, since the dropped etching chemical flows as it is, it is necessary to use a large amount of etching chemical in order to remove the plating film, and the efficiency of the usage of the etching chemical is also poor.

  In view of such circumstances, the present invention provides a method and apparatus for safely and efficiently removing a plating film formed on an electrode assembly when disassembling a cathode holder on which the electrode assembly is mounted. The purpose is to do.

  An etching apparatus according to the present invention is a cathode holder made of a cylindrical body, and includes a first protrusion that extends outward at a substantially right angle to the axis of the cylindrical body along at least a part of the outer peripheral portion of one end of the cylindrical body. An electrode etching apparatus which is provided facing the other end of the cathode holder and which forms the cathode of the plating apparatus. In order to solve the above problems, an etching apparatus according to the present invention includes a bottom plate, a side wall extending substantially perpendicular to the bottom plate and extending around the bottom plate, and an inner side extending along at least a part of the top of the side wall. And an etching container having an opening into which the cylindrical body can be inserted. The side wall has an orientation in which the electrode and the bottom plate face each other, and the first protrusion is placed on the second protrusion. Sometimes, it is configured to have a height that creates a gap between the electrode and the bottom plate.

  In the etching apparatus configured as described above, since the etching chemical can be injected into the etching container, the risk of scattering of the etching chemical is reduced, and the safety during operation is improved. In addition, the etching container has such a shape that the electrode to be etched is mounted downward and a gap is formed between the electrode and the bottom plate of the etching container, so that etching is performed until the liquid level exceeds the gap. By injecting chemicals, the etching chemicals can effectively spread over the entire surface of the electrode, and rapid and reliable etching can be performed with a small amount of chemicals.

  The etching container may have a drain opening provided in the bottom plate and a support leg provided below the bottom plate, and a drain pipe connected from the drain opening may be provided in a space formed by the support leg. .

  Further, the etching method of the present invention is a cathode holder made of a cylindrical body, and is a first holder extending outward substantially at right angles to the axis of the cylindrical body along at least a part of the outer peripheral portion of one end of the cylindrical body. A method of etching an electrode provided facing the other end of a cathode holder having a protrusion and forming a cathode of a plating apparatus, wherein the cathode holder to which the electrode is attached is removed from the plating apparatus after completion of the plating process; The cathode holder is turned upside down, and the cathode holder is placed in an etching container having an opening on the upper surface and provided with a second protrusion extending inward along at least a part of the periphery of the opening. A step of mounting the first protrusion on the second protrusion so that a gap is formed between the electrode and the bottom plate in a direction facing the bottom plate, and a gap is formed in the etching container. And a step of injecting an etching chemicals until liquid level around.

  In such an etching method, the cathode electrode device is attached to a dedicated etching container, and the etching chemical is injected into the etching container, thereby reducing the risk of scattering of the etching chemical and improving safety during operation. To do. Also, since the electrode to be etched is faced down and mounted so that there is a gap between the electrode and the bottom plate of the etching container, the etching chemical is injected until the liquid level exceeds the gap. Effectively spreads over the entire surface of the electrode, enabling rapid and reliable etching with a small amount of etching chemicals.

  The injection step can be performed in a draft chamber having an exhaust facility.

  As described above, according to the etching apparatus and the etching method of the cathode electrode device of the present invention, the cathode electrode device on which the plating film is formed is mounted on the etching container with the electrode facing downward, and the etching chemical is applied. Since the injection is performed, the electrode can be safely etched, and the amount of the etching chemical can be reduced.

  The details of the cathode electrode apparatus etching apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of an etching apparatus equipped with a cathode electrode device, and FIG. 2 is a perspective view of an etching container.

  The etching apparatus 2 includes a trough-shaped etching container 20, a support leg 24 that supports the etching container 20, a drain pipe 27, and a drain valve 28. The etching container 20 has a cylindrical side wall 21, a second flange 22 extending from the top of the side wall 21 toward the center, and a bottom plate 23 having a drain opening 26. The second flange 22 hooks the first flange 113 of the cathode holder 11 and fixes the cathode holder 11 to the etching container 20. Here, the second flange 22 may be partially missing as long as the above-described purpose can be achieved. More broadly, the etching container 20 is located inside along the at least part of the top of the side wall 21. It suffices to provide an extending protrusion, and to ensure an opening through which the side wall 111 of the cathode holder 11 can be inserted. However, when a protrusion extending along a part of the side wall 111 is used instead of the first flange 113 (see the background art column), the etching is performed so that the protrusions can easily come into contact without complicated adjustment. It is necessary to set the position and size of the protrusion provided on the container 20. The sidewall 21 is provided with a plurality of reinforcing ribs 25 extending toward the center of the etching container 20 in order to prevent deformation of the sidewall 21 due to heat generated when an etching chemical such as nitric acid is injected into the etching container 20. It has been. The reinforcing rib 25 can also have the functions of the second flange 22 and the above-described protrusions. In this case, the second flange 22 and the above-mentioned protrusions do not have to be provided. The bottom plate 23 may be flat, but may be provided with a gradient toward the drain opening 26 in order to facilitate the discharge of the etching chemical. The shape of the side wall 21 matches the shape of the cathode holder 11 and is usually a cylindrical shape. However, when the cathode holder 11 has a cylindrical body shape having a cross section other than a rectangular cross section or other circular cross section, the side wall 21 is matched to that. It can be a shape.

  The height Y of the side wall 21 is such that when the cathode holder 11 is mounted on the etching apparatus 2 with the first flange 113 placed on the second flange 22, the surface of the second electrode 15 is set. The dimension is set such that a predetermined gap X is generated between the bottom plate 23 and the base plate 23. The reason for providing the gap X is that if there is no gap X, that is, if the surface of the second electrode 15 comes into contact with the bottom plate 23, the etching chemical does not evenly wrap around the surface of the second electrode 15, and it takes time to wrap This is because the work efficiency is lowered. Although the gap X depends on the size of the cathode holder 11, as an example, when the outer diameter of the side wall 111 of the cathode holder 11 is about 200 mm, the gap X is about 20 mm. Although the height Y of the side wall 21 depends on the height of the side wall 111 of the cathode holder 11, the height of the side wall 111 is determined by the height of the frame 39 of the plating tank 31, and usually takes a constant value. The necessity of arranging a large number of etching apparatuses 2 having different heights Y of the side walls 21 is small. The inner diameter Z of the second flange 22 is slightly larger than the outer diameter of the side wall 111 of the cathode holder 11 in consideration of the mounting property of the cathode holder 11 to the etching container 20, and the first flange of the cathode holder 11. For fixing to 113, it is set smaller than the outer diameter of the first flange 113.

  The etching container 20 is required to have corrosion resistance and heat resistance, and is desirably inexpensive. From this point of view, the etching container 20 is most preferably made of vinyl chloride, but stainless steel or titanium material can also be used.

  A drain pipe 27 is connected to a drain opening 26 provided in the bottom plate 23, and etching chemicals such as nitric acid are discharged to the outside through a drain valve 28. The drain pipe 27 is connected to, for example, a neutralization tank (not shown) in order to intensively and easily process used etching chemicals. The drain pipe 27 and the drain valve 28 are also preferably made of vinyl chloride or the like for the reasons described above. The reason why the support legs 24 are provided in the etching container 20 is to secure an arrangement space for the drain pipe 27 in addition to the purpose of supporting and fixing the etching container 20 to the floor and foundation.

  Next, according to the flowchart of FIG. 3, the etching method of the cathode electrode apparatus 1 using the etching apparatus 2 of this invention is demonstrated. First, after the cathode electrode device 1 and the object to be plated 41 are attached to the plating tank 31 to perform plating, the plating solution 32 is extracted, and after the object to be plated 41 is removed, the cathode electrode device 1 is removed from the plating tank 31. (Step 51). At this time, a plating film is formed on the surface of the second electrode 15. Next, the cathode electrode device 1 is turned upside down, the first flange 113 of the cathode holder 11 is placed on the second flange 22 of the etching device 2, and the cathode electrode device 1 is mounted on the etching device 2 (step 52). . As a result, a gap X is formed between the surface of the second electrode 15 and the surface of the bottom plate 23 of the etching apparatus 2. At this time, the drain valve 28 is closed. Next, an injection means such as an injection hose 29 is set inside the cathode holder 11 or an etching chemical such as nitric acid is directly injected into the etching container 20 from a container containing the etching chemical (step 53). FIG. 4 is an explanatory view showing the state of the etching apparatus at this time. The etching chemical S has a liquid level T above the surface of the second electrode 15, and the surface of the second electrode 15 is completely Is immersed in an etching chemical S. After a predetermined time, it is confirmed by visual inspection or the like that the plating film has been removed if necessary, the drain valve 28 is opened, and the etching chemical is discharged from the etching container 20 (step 54). Thereafter, the cathode holder 11 is taken out of the etching container 20, the cathode electrode device 1 is turned upside down, the first electrode 12, the second electrode 15, and the packing 13 are replaced, the spacer 14 is maintained, and other necessary inspection work is performed. Perform (step 55).

  The amount of chemical to be injected is not particularly limited as long as the surface of the second electrode 15 is surely immersed in the chemical for etching, but the amount of the plating film adhering to the second electrode 15 is not limited. It is set appropriately considering the degree of removal and the like. Moreover, since the etching chemical after use contains a Cu component and the etching performance is lowered, it is desirable to replace it every time, but it is also possible to continue etching several times.

  As described above, according to the etching method of the present invention, the cathode electrode device 1 to be etched is mounted on the dedicated etching container 20 with the second electrode 15 facing downward, and the surface of the second electrode 15 is mounted. By injecting into the etching container 20 a small amount of etching chemical enough to immerse the second electrode 15, the second electrode 15 can be safely etched, and the amount of etching chemical used can be reduced.

  In addition, if the etching operation is performed in a draft chamber (not shown) with a well-exhausted environment, there is less risk of the etching chemical leaking to the outside, and the etching operation can be performed more safely. Further, by connecting the drain pipe 27 to the waste liquid collecting means provided in the draft chamber, the waste liquid can be reliably collected, and installation of dedicated equipment after the drain valve 28 is not required.

  In the above description, the etching of the electrode assembly having the first electrode and the second electrode has been described. However, the present invention is not limited to such an object, and one electrode is used. However, in the case of a plating apparatus other than the face-up method, it can be applied when it is necessary to remove the plating film attached to the cathode electrode apparatus.

  Moreover, there is no restriction | limiting in particular about the installation number of etching apparatuses, and it is also possible to install a plurality. Depending on the factory equipment, multiple plating tanks may be installed in the same place, and the plating process may be performed at the same time. Therefore, if multiple etching apparatuses are installed, multiple cathode electrodes are provided after the plating process. It is also possible to etch the device simultaneously. Even in this case, since the individual etching apparatuses can be operated independently, only the necessary number of bases can be operated.

It is a cross-sectional view of the etching apparatus of the present invention with the cathode electrode device mounted. It is a perspective view of the etching container shown in FIG. It is a flowchart which shows the etching method of this invention. It is explanatory drawing which shows the condition of the etching apparatus in step 53 of the flowchart of FIG. It is a conceptual side view which shows the whole structure of a plating apparatus. It is a conceptual side view near the cathode power supply device of a plating apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cathode electrode apparatus 11 Cathode holder 111 Side wall 113 1st flange 12 1st electrode 13 Packing 14 Spacer 15 2nd electrode 16 Fastener 17 Lead conductor 18 Opening 2 Etching apparatus 20 Etch container 21 Side wall 22 2nd flange 23 Bottom plate 24 Support leg 26 Drain opening 27 Drain pipe 28 Drain valve 31 Plating tank 39 Frame 41 Plated object

Claims (4)

A cathode holder comprising a cylindrical body, wherein the cathode holder has a first protrusion extending outward substantially at right angles to the axis of the cylindrical body along at least a part of the outer peripheral portion of one end of the cylindrical body. An electrode etching apparatus provided facing an end and forming a cathode of a plating apparatus,
A bottom plate; a side wall extending substantially perpendicularly to the bottom plate and extending around the bottom plate; and a second protrusion extending inward along at least a part of the top of the side wall, and the cylindrical body can be inserted therein An etching vessel having an opening;
The side wall has a height at which a gap is formed between the electrode and the bottom plate when the first projection is placed on the second projection in a direction in which the electrode and the bottom plate face each other. An etching apparatus. The etching container has a drain opening provided in the bottom plate, and a support leg provided below the bottom plate,
A drain pipe connected from the drain opening is provided in the space formed by the support legs.
The plating apparatus according to claim 1. A cathode holder comprising a cylindrical body, wherein the cathode holder has a first protrusion extending outward substantially at right angles to the axis of the cylindrical body along at least a part of the outer peripheral portion of one end of the cylindrical body. An electrode etching method provided facing an end and forming a cathode of a plating apparatus,
A step of removing the cathode holder, to which the electrode is attached, from the plating apparatus after completion of the plating step;
Reversing the cathode holder upside down;
A direction in which the electrode and the bottom plate of the etching container are opposed to an etching container provided with a second protrusion having an opening on the upper surface and extending inward along at least a part of the periphery of the cathode holder. And placing the first protrusion on the second protrusion such that a gap is formed between the electrode and the bottom plate; and
And a step of injecting an etching chemical into the etching container until the liquid level exceeds the gap.   The electrode etching method according to claim 3, wherein the implantation step is performed in a draft chamber having an exhaust facility.

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