ELECTRO-COPPER PLATING APPARATUS

Abstract

Disclosed herein is an electro-copper plating apparatus in which a cathode, an insoluble anode, a copper ball, and a plating solution are included in a single bath, wherein the plating solution includes manganese oxide; or an electro-copper plating apparatus including: a main bath including a cathode, an insoluble anode, and a plating solution; and a dissolution bath including a copper ball, and manganese oxide. According to the present invention, the manganese oxide having higher oxidation-reduction potential instead of using Fe3+ of the related art as the copper source in the electro-copper plating apparatus may be used to obtain a high effect in suppressing surface plating even at a low concentration.

Description

CROSS REFERENCE(S) TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. Section 119 of Korean Patent Application Serial No. 10-2012-0100969, entitled “Electro-Copper Plating Apparatus” filed on Sep. 12, 2012, which is hereby incorporated by reference in its entirety into this application.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to an electro-copper plating apparatus.

2. Description of the Related Art

An insoluble anode is used to minimize a foreign material when melting and using copper (Cu) in an electro-copper plating method. The electro-copper plating method using the insoluble anode may be largely classified into two methods according to a scheme of supplying the copper, that is, a method of supplementing CuO with a plating solution and a method of dissolving Fe³⁺ ion in the plating solution to supply a copper ion to a main bath.

FIG. 1 shows an electro-copper plating apparatus using an insoluble anode formed by a CuO supplement scheme, which is a scheme in which Cu consumed by a plating reaction in the main bath 10 is supplemented by putting CuO 15 powder into a separate dissolution bath 14, dissolving the input material by air agitation, or the like, and recirculating the material to the main bath 10. Here, the main bath 10 includes a cathode 11 and an anode 12, and inorganic materials of copper sulfate/sulfuric acid/chlorine are used as main components of the plating solution 13.

FIG. 2 shows an electro-copper plating apparatus using an insoluble anode formed by a Fe³⁺ scheme, which is a scheme in which when Cu consumed by a plating reaction in the main bath 10 is supplemented as a copper ion by putting a pure copper ball 25 into a plating solution of a separate dissolution bath 24, and circulating the input material to melt the copper ball 25 by a spontaneous reduction reaction of Fe³⁺ 26. Here, the main bath 20 includes a cathode 21 and an anode 22, and inorganic materials of copper sulfate/sulfuric acid/chlorine are used as main components of the plating solution 23.

Two schemes have been generally used in vertical and horizontal plating installation schemes. However, in the case of CuO, an efficiency of supplementing CuO is deteriorated due to an introduction of inorganic and organic impurities, and in the case of Fe³⁺, there is a limitation in improvement/reconstruction due to an exclusive scheme of a specific company, such that a development of an apparatus capable of replacing two schemes has been required.

RELATED ART DOCUMENT

(Patent Document 1) JP Patent Laid-Open Publication No. 2008-513985

SUMMARY OF THE INVENTION

An object of the present invention is to provide a novel electro-copper plating apparatus capable of replacing the electro-copper plating apparatus using an insoluble anode of the related art without generating problems of the electro-copper plating apparatus using an insoluble anode of the related art.

According to a first exemplary embodiment of the present invention, there is provided an electro-copper plating apparatus in which a cathode, an insoluble anode, a copper ball, and a plating solution are included in a single bath, wherein the plating solution includes manganese oxide.

The manganese oxide may be KMnO₄ or NaMnO₄.

The manganese oxide may be included in a concentration of 0.1 to 10 g/L.

The plating solution may include copper sulfate in a concentration of 50 to 350 g/L, sulfuric acid in a concentration of 10 to 150 g/L, and chlorine in a concentration of 10 to 200 mg/L.

The insoluble anode may be made of titanium (Ti) coated with platinum (Pt) or IrO₂.

According to a second exemplary embodiment of the present invention, there is provided an electro-copper plating apparatus including: a main bath including a cathode, an insoluble anode, and a plating solution; and a dissolution bath including a copper ball, and manganese oxide.

The copper may be supplied from the dissolution bath to the plating solution of the main bath by dissolving the copper to be a copper ion through a reaction of manganese oxide and the copper ball of the dissolution bath.

The manganese oxide may be KMnO₄ or NaMnO₄.

The manganese oxide may be included in a concentration of 0.1 to 10 g/L.

The plating solution of the electro-copper plating apparatus may include copper sulfate in a concentration of 50 to 350 g/L, sulfuric acid in a concentration of 10 to 150 g/L, and chlorine in a concentration of 10 to 200 mg/L.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an electro-copper plating apparatus using an insoluble anode formed by a CuO supplement scheme of the related art;

FIG. 2 shows an electro-copper plating apparatus using an insoluble anode formed by a Fe³⁺ scheme of the related art; and

FIGS. 3 and 4 show an electro-copper plating apparatus using an insoluble anode according to an embodiment of the present embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be described in detail.

Terms used in the present specification are for explaining the embodiments rather than limiting the present invention. Unless explicitly described to the contrary, a singular form includes a plural form in the present specification. The word “comprise” and variations such as “comprises” or “comprising,” will be understood to imply the inclusion of stated constituents, steps, operations and/or elements but not the exclusion of any other constituents, steps, operations and/or elements.

The present invention relates to an electro-copper plating apparatus using an insoluble anode. The electro-copper plating apparatus according to a preferred embodiment of the present invention is shown in FIG. 3.

Referring to FIG. 3, in the electro-copper plating apparatus, a cathode 111, an insoluble anode 112, a copper ball 115, and a plating solution 113 are included in a single bath 110, wherein the plating solution 113 includes manganese oxide 116.

The electro-copper plating apparatus according to FIG. 1 has a structure in which all components for electro-copper plating are included in one bath 110.

In the electro-copper apparatus, the cathode 111 is a material to be plated to thereby be electro-copper plated, which may be a printed circuit board having a panel shape.

In addition, the insoluble anode 112 may be made of a material, that is, titanium (Ti) coated with platinum (Pt) or IrO₂, and may be used to thereby minimize a foreign material when performing a plating process by using copper.

Further, a copper plating solution used in the electro-copper plating includes copper sulfate in a concentration of 50 to 350 g/L, sulfuric acid in a concentration of 10 to 150 g/L, and a chlorine ion in a concentration of 10 to 200 mg/L. In particular, the present invention includes a manganese oxide having strong oxidizing power as a component for supplying Cu of the insoluble anode.

The manganese oxide may be KMnO₄ or NaMnO₄. The manganese oxide serves to produce a copper ion by dissolving the copper ball. In addition, KMnO₂, which is a by-product produced after the above-described reaction, is re-oxidized to KMnO₄ and reproduced. The manganese oxide functions on a surface of the cathode, which is a material to be plated, to suppress a plating effect.

The manganese oxide is preferably included in a concentration of 0.1 to 10 g/L. In the case in which the concentration of the manganese oxide is less than 0.1 g/L, an effect of suppressing surface plating is not sufficient which may not obtain throwing power, and in the case in which the concentration of the manganese oxide is more than 10 g/L, a thickness of a plated surface is not sufficient or a plating process is not completely performed due to an excessive effect of suppressing surface plating, which is not preferred.

In addition, copper sulfate included in the plating solution may be included in a form of pentahydrate. In the case in which the concentration of copper sulfate is significantly low, since an efficiency of a cathode current is deteriorated, the concentration thereof is preferably 50˜350 g/L in order to obtain a stable plating efficiency.

Further, in the plating solution, it is preferable that the sulfuric acid is included in a concentration of 10˜150 g/L to increase conductance and smoothly flow an electric current.

In addition, the chlorine ion in the plating solution may be included in HCl or KCl form, and it is preferable to be included in a concentration of 10 to 200 mg/L in order to clearly show a smoothing effect combined with an additive.

Further, the electro-copper plating apparatus according to another preferred embodiment of the present invention is shown in FIG. 4. Referring to FIG. 4, the electro-copper plating apparatus includes a main bath 120 including a cathode 121, an insoluble anode 122, and a plating solution 123; and a dissolution bath 124 including a copper ball 125, and manganese oxide 126.

According to the embodiment, the electro-copper plating apparatus has a structure in which the cathode 121, the insoluble anode 122, and the plating solution 123 are included in the main bath 120, and the copper ball 125 and the manganese oxide 126 are separately included in the dissolution bath 124 in order to supply copper.

Therefore, when the copper ball 125 is put into the dissolution bath 124, the copper ball 125 is dissolved to be a copper ion by manganese oxide 126 to thereby be supplied to the plating solution 123 of the main bath 120. In addition, KMnO₂, which is a by-product produced after the above-described reaction, is re-oxidized to KMnO₄ in the anode 122 of the main bath 120 and reproduced. Therefore, the manganese oxide functions on a surface of the cathode 121, which is a material to be plated, to suppress a plating effect.

In the electro-copper apparatus, the cathode 121 is a material to be plated to thereby be electro-copper plated, which may be a printed circuit board having a panel shape.

In addition, the insoluble anode 122 may be made of a material, that is, titanium (Ti) coated with platinum (Pt) or IrO₂, and may be used to thereby minimize a foreign material when performing a plating process by using copper.

In addition, a copper plating solution used in the electro-copper plating includes copper sulfate in a concentration of 50 to 350 g/L, sulfuric acid in a concentration of 10 to 150 g/L, and a chlorine ion in a concentration of 10 to 200 mg/L. In particular, the present invention includes a manganese oxide having strong oxidizing power as a component for supplying Cu of the insoluble anode.

The manganese oxide is KMnO₄ or NaMnO₄, and preferably included in a concentration of 0.1 to 10 g/L. In the case in which the concentration of the manganese oxide is less than 0.1 g/L, an effect of suppressing a plating of a surface is not sufficient which may not obtain throwing power, and in the case in which the concentration of the manganese oxide is more than 10 g/L, a thickness of a plated surface is not sufficient or a plating process is not completely performed due to an excessive effect of suppressing a surface plating, which is not preferred.

In this case, a reaction in the insoluble anodes 112 and 122 is represented by the following reaction formula 1:

Mn²⁺+4H₂O→MnO₄⁻+8H⁺+5e⁻

Mn²⁺+2H₂O→MnO₂⁻+4H⁺+2e⁻  [Reaction Formula 1]

In addition, a reaction in the cathodes 111 and 121 is represented by the following reaction formula 2:

MnO₄−+8H⁺+5e⁻→Mn²⁺+4H₂O Eo=+1.51V

Cu²⁺+2e⁻→Cu Eo=+0.34V  [Reaction Formula 2]

Further, a reaction of generating the copper ion is represented by the following reaction formula 3: The reaction below is reacted in the dissolution bath having a structure in which the main bath and the dissolution bath are separately formed.

2MnO₄⁻+16H⁺+5Cu→2Mn²⁺+5Cu²⁺+8H₂O  [Reaction Formula 3]

In the present invention, since an oxidation-reduction potential of manganese oxide used as a copper source is +1.51V, which is higher than that of Fe³⁺/Fe²⁺, that is, +0.77V, a high effect in suppressing surface plating may be obtained even at a low concentration.

According to the present embodiment, the manganese oxide having higher oxidation-reduction potential instead of using Fe³⁺ of the related art as the copper source in the electro-copper plating apparatus may be used to obtain a high effect in suppressing surface plating even at a low concentration. In addition, the plating rate of the surface may be suppressed in the structure such as a through hole or a blind via hole than the inner portion of the hole to improve the throwing power.

Claims

1. An electro-copper plating apparatus in which a cathode, an insoluble anode, a copper ball, and a plating solution are included in a single bath, wherein the plating solution includes manganese oxide.

2. The electro-copper plating apparatus according to claim 1, wherein the manganese oxide is KMnO4 or NaMnO4.

3. The electro-copper plating apparatus according to claim 1, wherein the manganese oxide is included in a concentration of 0.1 to 10 g/L.

4. The electro-copper plating apparatus according to claim 1, wherein the plating solution includes copper sulfate in a concentration of 50 to 350 g/L, sulfuric acid in a concentration of 10 to 150 g/L, and chlorine in a concentration of 10 to 200 mg/L.

5. The electro-copper plating apparatus according to claim 1, wherein the insoluble anode is made of titanium (Ti) coated with platinum (Pt) or IrO2.

6. An electro-copper plating apparatus comprising:

a main bath including a cathode, an insoluble anode, and a plating solution; and

a dissolution bath including a copper ball, and manganese oxide.

7. The electro-copper plating apparatus according to claim 6, wherein the copper is supplied from the dissolution bath to the plating solution of the main bath by dissolving the copper to be a copper ion through a reaction of manganese oxide and the copper ball of the dissolution bath.

8. The electro-copper plating apparatus according to claim 6, wherein the manganese oxide is KMnO4 or NaMnO4.

9. The electro-copper plating apparatus according to claim 6, wherein the manganese oxide is included in a concentration of 0.1 to 10 g/L.

10. The electro-copper plating apparatus according to claim 6, wherein the plating solution of the electro-copper plating apparatus includes copper sulfate in a concentration of 50 to 350 g/L, sulfuric acid in a concentration of 10 to 150 g/L, and chlorine in a concentration of 10 to 200 mg/L.