JP2006225688A - Plating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plating device which is small in size, attains a plating with a small amount of a plating liquid and can form a uniform plating film on the surface of a substrate to be plated such as a semiconductor wafer. <P>SOLUTION: An anode tank 10 in which an anode electrode is arranged and a cathode tank 11 in which the substrate to be plated is arranged as a cathode electrode are equipped. The anode tank 10 and the cathode tank 11 are arranged in such a manner that the anode electrode and the substrate are confronted at prescribed intervals. The anode tank 10 and the cathode tank 11 are connected with piping 12 whose opening has a shape same as or similar to the shape of the substrate, or with piping obtained by bundling a plurality of capillaries in such a manner that the opening thereof is made the same as or similar to the shape of the substrate. A plating liquid is stored in the anode tank 10 and the cathode tank 11, and a plating power source E of applying prescribed plating voltage between the anode electrode and the substrate is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plating apparatus for plating a substrate such as a semiconductor wafer, and more particularly to metal plating for forming bumps (protruding electrodes) on a semiconductor wafer and fine trenches and via holes formed on the surface of the semiconductor wafer. The present invention relates to a plating apparatus suitable for performing buried metal plating in an opening.

For example, in the case of TAB (Tape Automated Bonding) and flip chip, a protruding connection electrode in which gold, copper, solder, or nickel is further laminated in a predetermined position (electrode) on the surface of a semiconductor chip on which wiring is formed A (bump) is formed, and electrical connection with a package electrode or a TAB electrode is widely performed through the bump. There are various bump forming methods, such as electroplating, vapor deposition, printing, and ball bump, which are relatively stable because the number of semiconductor chips can be increased and the pitch can be miniaturized. Many electroplating methods are used.

  According to the electroplating method, a high-purity metal film (plating film) can be easily obtained, and not only the deposition rate of the metal film is relatively high, but also the thickness of the metal film can be controlled relatively easily. Can do. Further, in the formation of a metal film on a semiconductor wafer, not only the film thickness but also the uniformity of the film thickness within the semiconductor wafer surface is strictly required in order to pursue high-density mounting, high performance, and high yield. . As for the electroplating film thickness distribution, a uniform plating film thickness can be obtained by making the metal ion supply rate distribution and potential distribution of the plating solution uniform.

As a technique for obtaining the uniform film thickness, there are those described in Patent Documents 1, 2, and 3. The plating apparatus described in Patent Document 1 is configured such that a flat plate made of a dielectric material in which holes concentric with the semiconductor wafer are formed between a semiconductor wafer as an anode electrode and a cathode electrode. The potential distribution near the surface of the substrate to be plated is made uniform. In the plating apparatus described in Patent Document 2, a plate-like dielectric plate is installed on the surface of the anode electrode facing the semiconductor wafer, and the dielectric plate is thinner at the center portion, and the outer peripheral portion. In this way, the potential distribution in the vicinity of the surface of the substrate to be plated is made uniform. Moreover, the plating apparatus described in Patent Document 3 arranges an adjustment plate in which a plurality of through holes are formed between the anode electrode and the semiconductor wafer, and adjusts the distribution state of the through holes of the adjustment plate. It is what I did. In some cases, a permeable membrane is disposed between the anode electrode and the semiconductor wafer.
JP 11-193497 A JP-A-11-152600 JP 2004-225129 A

  In order to form a metal plating film with a uniform thickness on the surface of the substrate to be plated, the potential distribution between the anode and the substrate to be plated is made uniform, particularly the potential distribution in the vicinity of the surface of the substrate to be plated is made uniform, and the metal ion supply rate distribution Need to be uniform. In order to make the potential distribution between the anode and the substrate to be plated uniform, by increasing the electric resistance between the anode and the substrate to be plated, the nonuniformity of the potential distribution is absorbed and a uniform potential distribution can be achieved. The above-mentioned prior arts exhibit their effects to some extent in that they each form a uniform film thickness, but in order to increase the electrical resistance between the anode and the substrate to be plated, it is necessary to enlarge the plating tank There is a problem that a large amount of plating solution is required.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a plating apparatus that is small in size and requires a small amount of plating solution and can form a uniform plating film on a surface of a substrate to be plated such as a semiconductor wafer. .

  In order to solve the above problems, an invention according to claim 1 includes an anode tank in which an anode electrode is disposed, and a cathode tank in which a substrate to be plated is disposed as a cathode electrode. The anode electrode and the substrate to be plated are arranged so as to face each other at a predetermined interval, and the anode tank and the cathode tank have an opening that is the same as or similar to the shape of the substrate to be plated, or a plurality of thin tubes. Are connected by piping bundled so as to be the same or similar to the shape of the substrate to be plated, the plating solution is accommodated in the anode tank and the cathode tank, and a predetermined plating voltage is provided between the anode electrode and the substrate to be plated. There is provided a plating apparatus characterized by including a plating power source for applying.

  According to a second aspect of the present invention, in the plating apparatus according to the first aspect, the length of the pipe is five times or more the diameter of the pipe.

  According to a third aspect of the present invention, in the plating apparatus according to the first aspect, the length of the narrow tube is at least five times the diameter of the narrow tube.

  According to a fourth aspect of the present invention, in the plating apparatus according to the first aspect, the material constituting the anode tank, the cathode tank, the piping, and the thin tube is a ceramic material, a resin material, a stainless material, a titanium material, or a steel plate. It is characterized by being a coated material.

  According to the plating apparatus of the present invention, the anode tank and the cathode tank have an opening cross-sectional shape that is the same as or similar to the shape of the substrate to be plated, or a plurality of narrow tubes whose integrated cross-sectional shape of the inner hole has a substrate to be plated. Since the pipes are bundled so as to be the same or similar to the shape of the electrode, increasing the length of this pipe increases the resistance between the anode electrode and the cathode electrode, so that Variation of the plating film thickness can be reduced. In addition, a plating film free from voids or seams can be formed even when trenches or via holes are buried.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are views showing a configuration example of a plating apparatus according to the present invention. FIG. 1 is an external view of the plating apparatus. FIG. 2A is an external view showing an anode electrode holder that holds an anode electrode. 2 (b) is an external view showing a semiconductor wafer holder (cathode holder) for holding a semiconductor wafer as a substrate to be plated, and FIG. 3 is a longitudinal sectional view of the plating apparatus. As shown in the figure, the present plating apparatus has a configuration in which an anode tank 10 and a cathode tank 11 are connected to each other by a pipe 12, and the anode tank 10 and the cathode tank 11 are communicated with each other via a pipe 12. Yes.

  An anode holder 14 that holds the anode electrode 13 is arranged inside the anode tank 10, and a cathode holder 15 that holds the semiconductor wafer W that becomes a cathode electrode is arranged inside the cathode tank 11. The anode tank 10 and the cathode tank 11 are connected by the pipe having the length L as described above, and the anode electrode 13 and the semiconductor wafer W are arranged so as to face each other in parallel. The anode tank 10 and the cathode tank 11 contain various plating solutions Q for metal plating, and the plating solution Q communicates with the pipe 12. E is a direct current plating power source. The anode of the plating power source E is connected to the anode electrode 13 by the wiring 16, and the cathode of the plating power source E is connected to the semiconductor wafer (substrate to be plated) W by the wiring 17.

  As shown in FIG. 2A, the anode electrode 13 is a mesh-like electrode formed by coating platinum on a titanium material, and is formed in a circular shape (the same shape as or similar to that of a semiconductor wafer). Is held on. The semiconductor wafer W is held on a plate-like cathode holder 15 as shown in FIG. The plating solution Q in the anode tank 10 is guided to the cathode tank 11 through the pipe 12, and the plating solution Q in the cathode tank 11 is passed through the constant temperature unit 19 by the pump 18 to a predetermined set temperature (for example, normal temperature to 65 ° C.). It is maintained, led to the anode tank 10 through the filter 20, and circulates in the plating apparatus. The anode holder 14 and the cathode holder 15 are made of an electrical insulating material such as a resin material.

  In the plating apparatus having the above configuration, by applying a predetermined DC voltage between the anode electrode 13 and the semiconductor wafer W from the plating power source E, the anode 13 passes through the plating solution Q in the pipe 12 to the semiconductor wafer W. A reaching plating current flows, and a metal plating film is formed on the surface of the semiconductor wafer W. In this case, if the length L of the pipe 12 is increased, the interelectrode resistance between the anode electrode 13 and the semiconductor wafer W increases, and the thickness of the plating film formed on the surface of the semiconductor wafer W becomes uniform. That is, since the resistance between the electrodes is large, the nonuniformity of the small potential distribution in the vicinity of the electrode or the like is absorbed and the potential distribution becomes uniform as a whole. Here, when the diameter (inner diameter) of the pipe 12 is D and the length is L, it is confirmed that if 5D ≦ L, a plating film having a uniform film thickness can be obtained. The opening shape of the pipe 12 is set to be the same as or similar to that of the semiconductor wafer W.

  FIG. 4 is a longitudinal sectional view showing another configuration example of the plating apparatus according to the present invention. In addition, since the external appearance structure of this plating apparatus is as substantially the same as FIG. 1, the description is abbreviate | omitted. 4, parts denoted by the same reference numerals as those in FIGS. 1 to 3 indicate the same or corresponding parts. As shown in the drawing, the plating apparatus has a plating solution sprayer 21 for spraying plating in the anode tank 10. As shown in FIG. 5, the plating solution sprayer 21 has a configuration in which a plurality of plating solution ejection nozzles 23 are provided on the side surface of a box-shaped main body 22, and each plating solution is ejected by guiding the plating solution to the body 22. A plating solution is ejected from the nozzle 23.

  As shown in FIG. 4, the plating solution sprayer 21 having the above configuration is disposed so as to face the side opposite to the anode electrode 13 side of the anode holder 14. A hole 14a is formed in the holding portion of the anode electrode 13 of the anode holder 14, and a plurality of plating solution ejection nozzles 23 of the plating solution sprayer 21 eject the plating solution toward the hole 14a. . When the plating solution Q that has passed through the filter 20 is introduced into the main body 22 of the plating solution sprayer 21, the plating solution ejected from the plating solution ejection nozzle 23 passes through the mesh-like anode electrode 13, the inside of the pipe 12, and the cathode tank. 11, and the plating solution Q in the cathode tank 11 is supplied to the plating solution sprayer 21 through the constant temperature unit 19 and the filter 20 by the pump 18 and blown out from the plating solution sprayer 21 in the anode tank 10. The anode tank 10 filled with the plating solution Q is blown out toward the pipe 12 and circulates.

  When a predetermined DC voltage is applied between the anode electrode 13 and the semiconductor wafer W from the plating power source E, the plating current flows from the anode electrode 13 through the plating solution Q in the pipe 12 to the semiconductor wafer W. A metal plating film is formed on the surface of the wafer W. Also in this case, if the length L of the pipe 12 is increased, the interelectrode resistance between the anode electrode 13 and the semiconductor wafer W increases, and the film thickness of the plating film formed on the surface of the semiconductor wafer W becomes uniform. . In addition, by ejecting the plating solution Q, the concentration of the plating solution in the pipe 12 becomes uniform, which contributes to the uniformization of the plating film.

  6 and 7 are diagrams showing another configuration example of the plating apparatus according to the present invention. FIG. 6 (a) is a schematic external view of the plating apparatus, FIG. 6 (b) is an AA sectional view, FIG. These are the longitudinal cross-sectional views of this plating apparatus. 6 and 7, the same reference numerals as those in FIGS. 1 to 5 denote the same or corresponding parts. As shown in the figure, in the present plating apparatus, the anode tank 10 and the cathode tank 11 are connected by a thin tube group 25 formed by bundling a plurality of thin tubes 24.

  In the plating apparatus having the above configuration, the plating solution Q in the cathode tank 11 is sent to the anode tank 10 through the constant temperature unit 19 and the filter 20 by the pump 18 and circulated. As a result, the plating solution in the anode tank 10 flows to the cathode tank 11 through each thin tube 24. By applying a predetermined DC voltage between the anode electrode 13 and the semiconductor wafer W from the plating power source E, the plating current flows from the anode electrode 13 through the plating solution Q in the narrow tube 24 to the semiconductor wafer W. A metal plating film is formed on the surface of the wafer W. Also in this case, if the length L of the pipe 24 is increased, the interelectrode resistance between the anode electrode 13 and the semiconductor wafer W increases, and the film thickness of the plating film formed on the surface of the semiconductor wafer W becomes uniform. . Here, when the diameter (inner diameter) of the thin tube 24 is D and the length of the thin tube 24 is L, it is confirmed that a plating film having a uniform film thickness can be obtained if 5D ≦ L. The opening shape of the thin tube group 25, that is, the collective shape of the opening of the thin tube 24 is set equal to or smaller than the diameter of the semiconductor wafer W.

  FIG. 8 is a longitudinal sectional view showing another configuration example of the plating apparatus according to the present invention. In addition, since the external appearance structure of this plating apparatus is as substantially the same as FIG. 6, the description is abbreviate | omitted. In FIG. 8, the same reference numerals as those in FIGS. 1 to 7 denote the same or corresponding parts. As shown in the drawing, the plating apparatus has a plating solution sprayer 21 for spraying plating in the anode tank 10. As shown in FIG. 5, the plating solution sprayer 21 has a configuration in which a plurality of plating solution ejection nozzles 23 are provided on the side surface of a box-shaped main body 22, and each plating solution is ejected by guiding the plating solution to the body 22. A plating solution is ejected from the nozzle 23.

  As shown in FIG. 8, the plating solution sprayer 21 having the above configuration is disposed so as to face the side opposite to the anode electrode 13 side of the anode holder 14. A hole 14a is formed in the holding portion of the anode electrode 13 of the anode holder 14, and a plurality of plating solution ejection nozzles 23 of the plating solution sprayer 21 eject the plating solution toward the hole 14a. . When the plating solution Q that has passed through the filter 20 is introduced into the main body 22 of the plating solution sprayer 21, the plating solution ejected from the plating solution ejection nozzle 23 passes through the mesh-like anode electrode 13 and passes through each of the narrow tubes 24 of the narrow tube group 25. Flows into the cathode chamber 11 and circulates.

  By applying a predetermined DC voltage from the plating power source E between the anode electrode 13 and the semiconductor wafer W, the plating current flows from the anode electrode 13 through the plating solution Q in the pipe 12 to the semiconductor wafer W, and the semiconductor. A metal plating film is formed on the surface of the wafer W. Also in this case, if the length L of the pipe 12 is increased, the interelectrode resistance between the anode electrode 13 and the semiconductor wafer W increases, and the film thickness of the plating film formed on the surface of the semiconductor wafer W becomes uniform. .

  In the plating apparatus shown in FIGS. 1 to 8, the material of the anode tank 10, the cathode tank 11, the pipe 12, and the thin tube 24 of the thin tube group 25 is made of polyvinyl chloride / heat-resistant PVC, polypropylene, Teflon (registered trademark), PVDF. Resin material such as acrylic, ceramic material, or stainless steel, titanium, steel plate coated with resin such as PVC or Teflon (registered trademark).

  In the above plating apparatus, by applying a voltage between the anode electrode 13 and the semiconductor wafer W from the plating power source E, a metal plating film of copper, nickel, gold, tin lead, tin silver or the like can be formed on the semiconductor wafer surface. . Examples of components of copper, nickel, gold, tin-lead and tin-silver metal plating solutions, that is, copper plating solution, nickel plating solution, gold plating solution, tin-lead solder plating solution and tin-silver plating solution are shown below.

Copper plating solution Copper sulfate pentahydrate: 60-240 g / L
Sulfuric acid: 40-200 g / L
Hydrochloric acid: 30-80 mg / L
Organic additive: Appropriate amount

Nickel plating solution Nickel salt: 50-130 g / L (as nickel concentration)
Boric acid: 30-50 g / L
Surfactant (pit prevention agent): appropriate amount

Gold plating solution Gold salt: 6-16g / L (as gold concentration)
Thallium salt: 5-12 mg / L (as thallium concentration)
Organic acid salt: appropriate amount

Tin-lead solder plating solution Tin salt: 1-30 g / L (as tin concentration)
Lead salt: 8-65g / L (as lead concentration)
Free acid: 70-130 g / L
Organic additive: Appropriate amount

Tin silver plating solution Tin salt: 35-60g / L (as tin concentration)
Silver salt: 0.3-2.5 g / L (as silver concentration)
Free acid: 60-200 g / L
Chelating agent: Appropriate amount Organic additive: Appropriate amount

  As described above, according to the present plating apparatus, the anode tank 10 and the cathode tank 11 have an opening cross-sectional shape that is the same as or similar to the shape of a semiconductor wafer that is a substrate to be plated, or an opening aggregate shape of a plurality of thin tubes 24. Are connected by a thin tube group 25 bundled so as to have the same shape as or similar to the shape of the semiconductor wafer W, the resistance between the anode electrode 13 and the semiconductor wafer W is increased, and the plating film thickness in the surface of the semiconductor wafer is increased. Can be reduced, and a metal plating film having a uniform film thickness can be formed. Even when trenches or via holes are embedded, a plating film without voids or seams can be formed.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible.

It is an external view which shows the structural example of the plating apparatus which concerns on this invention. FIG. 2A is an external view of an anode holder, and FIG. 2B is an external view of a cathode holder. It is a longitudinal cross-sectional view which shows the structural example of the plating apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows the structural example of the plating apparatus which concerns on this invention. It is an external view of a plating solution sprayer. It is an external view which shows the other structural example of the plating apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows the other structural example of the plating apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows the other structural example of the plating apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Anode tank 11 Cathode tank 12 Piping 13 Anode electrode 14 Anode holder 15 Cathode holder 16 Wiring 17 Wiring 18 Pump 19 Constant temperature unit 20 Filter 21 Plating solution sprayer 22 Plating solution sprayer body 23 Plating solution ejection nozzle 24 Narrow tube 25 Narrow tube group E Plating power supply

Claims (4)

  An anode tank in which an anode electrode is disposed and a cathode tank in which a substrate to be plated is disposed as a cathode electrode are provided. The anode tank and the cathode tank are opposed to each other at a predetermined interval. The anode tank and the cathode tank are arranged so that the opening has the same or similar shape as the shape of the substrate to be plated, or a plurality of narrow tubes have the same or similar shape as the shape of the substrate to be plated. A plating apparatus comprising a plating power source that is connected to a pipe bundled together, contains a plating solution in the anode tank and the cathode tank, and applies a predetermined plating voltage between the anode electrode and the substrate to be plated . The plating apparatus according to claim 1,
The length of the said piping has a length 5 times or more of the diameter of this piping, The plating apparatus characterized by the above-mentioned. The plating apparatus according to claim 1,
The length of the said thin tube has a length 5 times or more of the diameter of this thin tube, The plating apparatus characterized by the above-mentioned. The plating apparatus according to claim 1,
The material constituting the anode tank, the cathode tank, the piping, and the thin tube is a material obtained by applying a resin coating to a ceramic material, a resin material, a stainless steel material, a titanium material, or a steel plate.

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