KR20130033147A - Surface treating agent and process for surface treating printed circuit board - Google Patents

Surface treating agent and process for surface treating printed circuit board Download PDF

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Publication number
KR20130033147A
KR20130033147A KR1020110097045A KR20110097045A KR20130033147A KR 20130033147 A KR20130033147 A KR 20130033147A KR 1020110097045 A KR1020110097045 A KR 1020110097045A KR 20110097045 A KR20110097045 A KR 20110097045A KR 20130033147 A KR20130033147 A KR 20130033147A
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KR
South Korea
Prior art keywords
surface treatment
corrosion inhibitor
printed circuit
circuit board
gold
Prior art date
Application number
KR1020110097045A
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Korean (ko)
Inventor
조현철
유종수
김치성
Original Assignee
삼성전기주식회사
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Priority to KR1020110097045A priority Critical patent/KR20130033147A/en
Publication of KR20130033147A publication Critical patent/KR20130033147A/en

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
    • C23F11/16—Sulfur-containing compounds
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2105/00—Erosion prevention

Abstract

PURPOSE: A surface treating solution and a method for treating a surface of a PCB(Printed Circuit Board) are provided to prevent the corrosion of metal when a gold ion is plated on the metal of an external layer circuit by being substituted as the solution includes corrosion inhibitor. CONSTITUTION: A surface treating solution comprises a substitution catalyst, a gold ion, pure water, and a corrosion inhibitor. The corrosion inhibitor includes alkaline sulfurous acid components. The solution includes 2.5%-4.7% of the corrosion inhibitor. [Reference numerals] (S110) Step of providing a printed circuit board formed with a circuit layer; (S120) Step of plating the printed circuit board with nickel; (S130) Step of preparing a surface treating solution including a corrosion inhibitor; (S140) Step of performing gold strike with the surface treating solution including the corrosion inhibitor; (S150) Step of performing gold plating with a surface treating solution including no corrosion inhibitor;

Description

SURFACE TREATING AGENT AND PROCESS FOR SURFACE TREATING PRINTED CIRCUIT BOARD}

The present invention relates to a surface treatment liquid and a surface treatment method of a printed circuit board.

Recently, due to the miniaturization of electronic devices, printed circuit boards are also miniaturized. With the miniaturization of printed circuit boards, high wiring density is required. For the surface treatment of such wiring, an electroless plating method is adopted. Generally, after forming an electroless nickel film in wiring, an electroless gold plating film is formed. In recent years, a substitution type electroless gold plating method has been performed when gold plating is formed on wirings for surface treatment. However, when a substitution type electroless gold plating method is performed to form a gold plating of a certain thickness, problems such as surface corrosion of the nickel film and the resulting peeling of gold plating occur due to the use of the substitution chemical.

The present invention provides a surface treatment liquid and a surface treatment method of a printed circuit board which can prevent corrosion of metal during surface treatment of a printed circuit board.

According to one aspect of the invention, there is provided a surface treatment liquid which is an aqueous solution containing a substitution catalyst, gold ions, pure water and a corrosion inhibitor.

Corrosion inhibitors may include an alkaline sulfite component.

Corrosion inhibitors may contain 2.5% to 4.7%.

According to another aspect of the invention, the step of providing a printed circuit board with a circuit layer, performing a nickel plating on the circuit layer of the printed circuit board, preparing a surface treatment liquid containing a corrosion inhibitor, nickel plating phase Forming a first gold plated layer by performing a gold strike with a surface treatment liquid containing a corrosion inhibitor in the first layer; And forming a second gold plating layer by performing gold plating with a surface treatment liquid for thickness plating on the first plating layer.

In preparing the surface treatment liquid, the corrosion inhibitor may include an alkaline sulfite component.

In preparing the surface treatment liquid, the surface treatment liquid may include 2.5% to 4.7% of a corrosion inhibitor.

In the step of performing Au-Strike, the surface treatment liquid containing the corrosion inhibitor on the nickel plating may be substituted to form a first gold plating layer.

In the gold plating, the surface treatment liquid for thickness plating may be substituted on the first gold plating layer to form a second gold plating layer.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

The surface treatment liquid and the surface treatment method of the printed circuit board according to the embodiment of the present invention can prevent the corrosion of the metal during the surface treatment of the printed circuit board.

1 is a flowchart illustrating a surface treatment method of a printed circuit board according to an exemplary embodiment of the present invention.
2 to 4 are exemplary views showing the surface treatment principle of the surface treatment liquid according to an embodiment of the present invention.
Fig. 5 is a sectional view of wiring after performing surface treatment using a conventional surface treatment liquid.
6 is a cross-sectional view of a wiring after performing a surface treatment using the surface treatment liquid according to the embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description and examples taken in conjunction with the accompanying drawings. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. In this specification, the terms first, second, etc. are used to distinguish one element from another, and the element is not limited by the terms.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the surface treatment liquid and the surface treatment method of a printed circuit board according to an embodiment of the present invention.

Surface treatment liquid

According to an embodiment of the present invention, a surface treatment liquid is provided.

The surface treatment liquid according to an embodiment of the present invention is an aqueous solution used for surface treatment after forming an outer layer circuit including a wiring, an electrode, and the like in a printed circuit board. When the surface treatment solution is surface treated, the surface treatment may be performed by plating the ions of the surface treatment solution with the metal of the outer layer circuit.

According to an embodiment of the present invention, the surface treatment liquid may include other components including a substitution catalyst, gold ions, a corrosion inhibitor, and pure water. Substitution catalysts are catalysts that allow gold ions to be substituted with the metal to be plated. For example, the substitution catalyst may be TKK-51 sold by Uyemura. However, this is only one embodiment and is not limited to the type of substitution catalyst. That is, the substitution catalyst may be selected and used among not only TKK-51 but also substitution catalysts used for surface treatments that are commonly used.

During surface treatment, gold ions are substituted with metals in the outer layer circuit and plated in place. Gold ions can be made water soluble. The water-soluble gold ions are, for example, potassium cyanide potassium, potassium cyanide potassium, potassium chloride cadmium, sodium chloride dibasic, gold ammonium sulfite, gold potassium sulfite, sodium gold sulfite, sodium gold thiosulfate, thio Gold sulfate and mixtures thereof.

Corrosion inhibitors can prevent the metals from corroding when gold ions are replaced with metals in the outer layer circuit upon surface treatment. Here, the prevention may include preventing the corrosion of the metal from occurring and suppressing the corrosion occurring beyond the degree or limit.

 Corrosion inhibitors may be composed of alkaline sulfite components. In an embodiment of the present invention, corrosion inhibitors composed of alkaline sulfite components may be used in the range of 2.5% to 4.7%. In producing the surface treatment liquid, when the corrosion inhibitor is made up of less than 2.5%, the metal corrosion protection role of the outer layer circuit by the gold ions cannot be efficiently performed. In addition, when the surface treatment solution is generated, when the corrosion inhibitor is more than 4.7%, the stability of the drug may be inhibited by an increase in the reducing agent component included in the drug. In addition, the gold coating is likely to turn red after plating.

Other components may include pure water. In addition to the pure water, other components may be added by selecting a crystal regulator, a surfactant, a buffer, and the like as necessary.

According to an exemplary embodiment of the present invention, the surface treatment liquid including the substitution catalyst, the gold ion, the corrosion inhibitor, and other components including pure water may be used by heating in a bath after adjusting to a predetermined PH. The pH range of the surface treatment liquid can usually be used in the range of 4-8. In an embodiment of the present invention, the PH range may be 5, but it is not limited to one embodiment, and the surface treatment liquid may be used in the PH 4-8 range.

The surface treatment liquid according to the embodiment of the present invention described above includes a corrosion inhibitor, so that when metal ions are plated by being substituted with metal in an outer layer circuit, the metal may be prevented from being corroded.

Surface treatment method

1 is a flowchart illustrating a surface treatment method of a printed circuit board according to an exemplary embodiment of the present invention.

Referring to FIG. 1, first, a printed circuit board on which a circuit layer is formed is provided.

The printed circuit board may have a single layer structure. Alternatively, the printed circuit board may have a multilayer structure including an inner circuit layer and an outer circuit layer. The circuit layer in the embodiment of the present invention is a circuit layer formed on the outermost layer of the printed circuit board and formed before the surface treatment step.

Subsequently, nickel plating is performed on the printed circuit board.

Nickel plating may be performed on the circuit layer formed on the printed circuit board. The circuit layer may include a wiring, an electrode, and the like. The wiring and the electrode of the circuit layer may be formed of copper (Cu). That is, primary surface treatment can be performed by performing nickel plating on the copper wiring of the printed circuit board.

Subsequently, a surface treatment liquid containing a corrosion inhibitor according to an embodiment of the present invention is prepared. (S130)

The surface treatment liquid is used for surface treatment of a circuit layer formed on a printed circuit board. The surface treatment liquid according to the embodiment of the present invention may include other components including a substitution catalyst, gold ions, a corrosion inhibitor, and pure water. Here, the corrosion inhibitor is to prevent corrosion of the metal when the gold ions are plated with gold by replacing the metal in the circuit layer during the surface treatment with the surface treatment liquid. According to an embodiment of the present invention, the corrosion inhibitor may be composed of an alkaline sulfite component. Corrosion inhibitors may be comprised in the range of 2.5% to 4.7% of the surface treatment liquid. Here, when the corrosion inhibitor is less than 2.5%, it is difficult to perform the corrosion protection function of the metal during the surface treatment of the circuit layer of the printed circuit board. In addition, if the corrosion inhibitor is more than 4.7%, the stability of the drug may be inhibited by the increase of the reducing agent component included in the drug. In addition, the gold coating is likely to turn red after plating. Therefore, while performing the role of corrosion protection during the surface treatment, in order to maintain the composition conditions of the surface treatment solution to the same as the existing will be configured by adjusting the ratio of the corrosion inhibitor within the range of 2.5% to 4.7%.

Subsequently, gold strikes may be performed (Au-Strike).

The surface treatment may be performed using the surface treatment solution containing the corrosion inhibitor provided in step S130 described above. In this case, when the gold strike is performed, the surface treatment liquid according to the embodiment of the present invention may be replaced by plating to form a thin first gold plating layer on the nickel plating. In this case, since the surface treatment liquid used for the surface treatment of the printed circuit board includes a corrosion inhibitor, it is noted that nickel formed on the copper wiring of the printed circuit board is corroded during the surface treatment such as a gold strike step or a gold plating step to be performed later. It can prevent.

Subsequently, gold plating may be performed.

A thick second gold plating layer may be formed using the surface treatment liquid on the thin first gold plating layer formed on the nickel by the gold strike performed in step S140 described above. In this case, the surface treatment liquid used may be a surface treatment liquid for thickness plating. Here, the surface treatment liquid for the thickness plating is a surface treatment liquid does not contain a corrosion inhibitor according to an embodiment of the present invention. As such, the thick second gold plating layer formed in step S150 may be formed by substitution plating by a surface treatment liquid that does not include a corrosion inhibitor according to an embodiment of the present invention.

In the surface treatment method of the printed circuit board according to the embodiment of the present invention, by the gold strike performing step (S140) and the gold plating performing step (S150), the thickness of 0.4㎛ or more in the wiring of the circuit layer formed on the printed circuit board A gold plating layer may be formed.

2 to 4 are exemplary views showing the surface treatment principle of the surface treatment liquid according to an embodiment of the present invention.

Referring to Figure 2, the wiring of the circuit layer formed on the printed circuit board is formed of a metal. In the embodiment of the present invention, the metal forming the wiring may be copper 140. However, the metal forming the wiring is not limited to the copper 140 and may be formed by selecting among conductive materials.

As such, after the wiring is formed of copper 140, surface treatment may be performed. When surface treatment is performed on the copper 140 wiring, first, nickel 120 plating may be performed on the copper 140 wiring. In addition, after plating nickel 120 on the copper 140 wiring, the surface treatment liquid according to the embodiment of the present invention is coated. The surface treatment liquid according to the embodiment of the present invention may include other components including gold ions, a substituted catalyst solution, a corrosion inhibitor 130 and pure water. Here, the corrosion inhibitor 130 is composed of an alkaline sulfite component.

Referring to FIG. 3, the surface treatment liquid is applied to the nickel 120, whereby the substitution for the gold plating 110 is performed. The corrosion inhibitor 130 may form a protective layer on the surface of the nickel 120. Thus, the nickel 120 surface can be protected from corrosion. In addition, the corrosion inhibitor 130 may improve the substitution rate of the gold ions since the protective layer is not formed on the surface where the gold ions are substituted.

Referring to FIG. 4, it can be seen that the gold plating 110 is formed on the surface of the nickel 120 using the surface treatment solution. That is, the corrosion inhibitor 130 of the surface treatment solution suppresses side reactions generated when gold ions are substituted on the surface of nickel 120, thereby improving the substitution rate of gold ions, thereby providing stable gold plating on the surface of nickel 120. 110 may be formed.

In the embodiment of the present invention, in the surface treatment method, the surface treatment object has been described as an example by wiring, but the surface treatment object is not limited thereto. That is, the object to which the surface treatment method using the surface treatment liquid according to the embodiment of the present invention is performed may be any configuration that requires surface treatment among outer layer circuits formed of metal including wiring and electrodes in a printed circuit board.

Fig. 5 is a sectional view of wiring after performing surface treatment using a conventional surface treatment liquid.

Referring to FIG. 5, the gold plating 110 formed by the surface treatment of the printed circuit board 100 using the conventional surface treatment liquid and the nickel 120 disposed under the gold plating 110 can be confirmed. Referring to FIG. 5, when the surface treatment of the printed circuit board 100 is performed using a conventional surface treatment solution, the degree of corrosion 121 of the nickel 120 may be confirmed.

6 is a cross-sectional view of a wiring after performing a surface treatment using the surface treatment liquid according to the embodiment of the present invention.

Referring to FIG. 6, the gold plating 110 formed by the surface treatment of the printed circuit board 100 using the surface treatment liquid according to the exemplary embodiment of the present invention and the nickel 120 disposed under the gold plating 110 are identified. Can be. Referring to Figure 6, when the surface treatment of the printed circuit board 100 using the surface treatment liquid according to an embodiment of the present invention, the corrosion 121 of the nickel 120 can be confirmed.

That is, when the surface treatment was performed using the surface treatment liquid according to the embodiment of the present invention, the degree of corrosion 121 of the nickel 120 was reduced than when the surface treatment was performed using the conventional surface treatment liquid. This can be confirmed through the comparison of FIGS. 5 and 6.

Although the present invention has been described in detail by way of examples, it is intended to specifically describe the present invention, and the surface treatment method of the surface treatment liquid and the printed circuit board according to the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and changes can be made in the present invention without departing from the spirit and scope of the invention as set forth in the claims below.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: printed circuit board 110: gold plating
120: nickel 130: corrosion inhibitor
140: copper

Claims (8)

Surface treatment liquid which is an aqueous solution containing a substitution catalyst, gold ion, pure water, and a corrosion inhibitor.
The method according to claim 1,
The corrosion inhibitor comprises a surface of an alkaline sulfite component.
The method according to claim 1,
Surface treatment liquid, characterized in that containing the corrosion inhibitor 2.5% to 4.7%.
Providing a printed circuit board having a circuit layer formed thereon;
Performing nickel plating on the circuit layer of the printed circuit board;
Preparing a surface treatment solution containing a corrosion inhibitor;
Forming a first gold plating layer by performing a gold strike on the nickel plating with a surface treatment liquid containing the corrosion inhibitor; And
Forming a second gold plating layer by performing gold plating on the first gold plating layer with a surface treatment solution for thickness plating;
Surface treatment method of a printed circuit board comprising a.
The method of claim 4,
In the step of preparing the surface treatment liquid,
The corrosion inhibitor is a surface treatment method of a printed circuit board, characterized in that it comprises an alkaline sulfite component.
The method of claim 4,
In the step of preparing the surface treatment liquid,
And the surface treatment solution contains 2.5% to 4.7% of the corrosion inhibitor.
The method of claim 4,
Performing the gold strike (Au-Strike)
The surface treatment liquid containing the said corrosion inhibitor on said nickel plating replaces, and forms the said 1st gold plating layer, The surface treatment method of the printed circuit board characterized by the above-mentioned.
The method of claim 4,
Forming the second gold plating layer,
The surface treatment liquid for plating the thickness on the first gold plating layer by the substitution reaction, the surface treatment method of a printed circuit board, characterized in that to form the second gold plating layer.

KR1020110097045A 2011-09-26 2011-09-26 Surface treating agent and process for surface treating printed circuit board KR20130033147A (en)

Priority Applications (1)

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KR1020110097045A KR20130033147A (en) 2011-09-26 2011-09-26 Surface treating agent and process for surface treating printed circuit board

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020110097045A KR20130033147A (en) 2011-09-26 2011-09-26 Surface treating agent and process for surface treating printed circuit board

Publications (1)

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KR20130033147A true KR20130033147A (en) 2013-04-03

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