Palladium catalyst liquid

Abstract

The present invention can provide a palladium catalyst solution which can suppress corrosion of copper, can impart excellent nickel plating deposition properties to a copper surface, and can impart excellent patterning properties by suppressing nickel plating enlargement on copper. This palladium catalyst solution is characterized by containing (A) an organic acid, (B) a chloride, and (C) a palladium salt.

Description

Technical Field

[0001] The invention relates to a palladium catalyst liquid. Background Art

[0002] In electronic related fields such as printed wiring boards, semiconductor packages, and electronic components, electroless nickel plating is performed on copper circuits.

[0003] When electroless nickel plating is performed on a copper circuit, an inorganic acid such as hydrochloric acid or sulfuric acid is used as a palladium catalyst liquid.

[0004] However, the palladium catalyst solution using the above-mentioned acid has a problem of copper corrosion.

[0005] Conventionally, it is disclosed that a substrate having a copper surface is brought into contact with a composition containing palladium ions and then brought into contact with a composition containing an organic acid such as an organic amine carboxylic acid (see Patent Document 1).

[0006] However, after the step of contacting the composition disclosed in Patent Document 1 with the palladium ion-containing composition, the composition needs to be further washed in order to remove the palladium ions and their precipitates, which makes the steps complicated.

[0007] In addition, the composition disclosed in Patent Document 1 has a problem that the corrosion suppression of copper is insufficient.

[0008] In addition, the composition disclosed in Patent Document 1 has problems in that nickel plating deposition is not sufficient in the next step and nickel plating easily spreads, resulting in poor patterning.

[0009] Therefore, there is a demand for the development of a palladium catalyst solution that can suppress copper corrosion, impart excellent nickel plating deposition properties to the copper surface, and suppress nickel plating expansion on copper to impart excellent pattern properties.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: Japanese Patent No. 5570585 Summary of the invention

[0013] Problems to be solved by the invention

[0014] The present invention has been made in view of the above problems, and its object is to provide a palladium catalyst solution that can inhibit copper corrosion, impart excellent nickel plating precipitation properties to the copper surface, and inhibit nickel plating expansion on copper to impart excellent pattern properties.

[0015] Methods for solving problems

[0016] The inventors of the present invention have conducted intensive studies to achieve the above-mentioned object and have found that the above-mentioned object can be achieved by using a palladium catalyst solution containing (A) an organic acid, (B) a chloride and (C) a palladium salt, thereby completing the present invention.

[0017] That is, the present invention relates to the following palladium catalyst solution.

[0018] 1. A palladium catalyst solution, characterized in that it contains (A) an organic acid, (B) a chloride and (C) a palladium salt.

[0019] 2. The palladium catalyst liquid according to item 1, wherein the organic acid is at least one selected from the group consisting of organic sulfonic acid, organic carboxylic acid and organic phosphonic acid.

[0020] 3. The palladium catalyst solution according to item 1 or 2, wherein the content of the organic acid is 10 to 250 g / L.

[0021] 4. The palladium catalyst liquid according to item 1 or 2, wherein the chloride is at least one selected from the group consisting of sodium chloride, potassium chloride, ammonium chloride and calcium chloride.

[0022] 5. The palladium catalyst solution according to item 1 or 2, wherein the content of the chloride is 3 to 50 g / L.

[0023] 6. The palladium catalyst liquid as described in item 1 or 2, wherein the palladium salt is at least one selected from palladium sulfate, palladium chloride, palladium oxide, palladium iodide, palladium bromide, palladium nitrate, palladium acetate, tetraamminepalladium chloride, dinitrodiamminepalladium and dichlorodiethylenediaminepalladium.

[0024] 7. The palladium catalyst solution according to item 1 or 2, wherein the content of the palladium salt is 1 to 100 mg / L.

[0025] Effects of the Invention

[0026] The palladium catalyst solution of the present invention can suppress copper corrosion, can provide excellent nickel plating precipitation properties on the copper surface, and can suppress nickel plating expansion on copper to provide excellent pattern properties. DETAILED DESCRIPTION

[0027] Hereinafter, the present invention will be described in detail.

[0028] 1. Palladium catalyst liquid

[0029] The palladium catalyst liquid of the present invention is characterized in that it contains (A) an organic acid, (B) a chloride and (C) a palladium salt. Hereinafter, they are respectively represented as "(A) component", "(B) component" and "(C) component". The palladium catalyst liquid of the present invention can inhibit the corrosion of the copper surface and impart excellent nickel plating precipitation to the copper surface by containing the above-mentioned (A) component and (C) component. In addition, the palladium catalyst liquid of the present invention can inhibit the corrosion of the copper surface and inhibit the expansion of nickel plating on copper, thereby imparting excellent pattern properties by containing the above-mentioned (B) component. The role of achieving the above-mentioned effect by containing the (C) component is still unclear, and it is believed that this is because the palladium catalyst liquid of the present invention improves the selective precipitation of palladium to the copper surface by containing the above-mentioned (C) component, and local corrosion of the surface is inhibited. That is, the palladium catalyst liquid of the present invention can inhibit the corrosion of copper, impart excellent nickel plating precipitation to the copper surface, and inhibit the expansion of nickel plating on copper, thereby imparting excellent pattern properties.

[0030] (A)Ingredients

[0031] The component (A) is an organic acid. The palladium catalyst solution of the present invention can suppress corrosion of the copper surface and provide excellent nickel plating deposition properties on the copper surface by containing the component (A).

[0032] The organic acid is not particularly limited, and examples thereof include organic sulfonic acid, organic carboxylic acid, organic phosphonic acid, etc. Among these, organic sulfonic acid is preferred because it can better suppress corrosion on the copper surface and further improve nickel plating deposition properties on the copper surface.

[0033] Examples of the organic sulfonic acid include aliphatic sulfonic acids having 1 to 5 carbon atoms, such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and pentanesulfonic acid; aromatic sulfonic acids, such as toluenesulfonic acid, pyridinesulfonic acid, and phenolsulfonic acid, etc. Among these, methanesulfonic acid is preferred because it can better inhibit corrosion on the copper surface and further improve the nickel plating deposition properties on the copper surface.

[0034] Examples of organic carboxylic acids include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, sebacic acid, maleic acid, and fumaric acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, etc. Among these, succinic acid is preferred because it is more excellent in inhibiting corrosion on the copper surface and further improves the nickel plating precipitation property on the copper surface.

[0035] Examples of the organic phosphonic acid include methyl diphosphonic acid, amine tris(methylene phosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), aminotrimethylenephosphonic acid (NTMP), ethylenediaminetetrakis(methylene phosphonic acid), etc. Among these, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) is preferred because it is more excellent in suppressing corrosion on the copper surface and further improves the nickel plating deposition property on the copper surface.

[0036] The above-mentioned organic acids may be used alone or in combination of two or more.

[0037] The concentration of the organic acid in the palladium catalyst solution is not particularly limited, but is preferably 10 to 250 g / L, more preferably 50 to 200 g / L, and even more preferably 80 to 150 g / L. In addition, regarding the concentration of the organic acid, for example, when 70% methanesulfonic acid is used, it is the amount of methanesulfonic acid in the 70% methanesulfonic acid, for example, when 70% methanesulfonic acid is used at a concentration of 150 g / L, the concentration of methanesulfonic acid is 105 g / L.

[0038] (B) Ingredients

[0039] The component (B) is a chloride. The palladium catalyst solution of the present invention can suppress corrosion of the copper surface and inhibit expansion of nickel plating on copper by containing the component (B), thereby providing excellent patterning properties.

[0040] Chloride is not particularly limited, and sodium chloride, potassium chloride, ammonium chloride, calcium chloride, etc. can be cited. Among these, sodium chloride is preferred from the aspect of inhibiting corrosion of the copper surface and inhibiting the expansion of nickel plating on the copper to give a more excellent pattern. In addition, as chloride, chlorides other than hydrochloric acid are preferably used from the aspect of further inhibiting corrosion of copper, and the palladium catalyst solution of the present invention preferably does not contain hydrochloric acid.

[0041] The above chlorides may be used alone or in combination of two or more.

[0042] The concentration of the chloride in the palladium catalyst liquid is not particularly limited, but is preferably 3 to 50 g / L, more preferably 5 to 30 g / L, and even more preferably 7 to 20 g / L.

[0043] (C) Ingredients

[0044] The component (C) is a palladium salt. The palladium catalyst solution of the present invention can suppress corrosion of the copper surface and provide excellent nickel plating deposition properties on the copper surface by containing the component (C).

[0045] The palladium salt is not particularly limited, and examples thereof include palladium sulfate, palladium chloride, palladium oxide, palladium iodide, palladium bromide, palladium nitrate, palladium acetate, tetraammine palladium chloride, dinitrodiammine palladium, dichlorodiethylenediamine palladium, etc. Among these, palladium sulfate is preferred from the perspective of better corrosion suppression on the copper surface and further improved nickel plating precipitation on the copper surface.

[0046] The above palladium salts may be used alone or in combination of two or more.

[0047] The concentration of the palladium salt in the palladium catalyst solution is not particularly limited, but is preferably 1 to 100 mg / L, more preferably 20 to 80 mg / L, still more preferably 30 to 70 mg / L, and particularly preferably 40 to 60 mg / L.

[0048] Other ingredients

[0049] The palladium catalyst solution of the present invention may contain other components in addition to the above-mentioned components (A), (B) and (C), and other components include stabilizers and the like.

[0050] Solvents

[0051] The palladium catalyst solution of the present invention preferably contains the above-mentioned components (A), (B) and (C), and other components contained as required, in a solvent at the above-mentioned contents. As such a solvent, water is preferred from the aspects of low environmental burden and excellent safety.

[0052] The content of the solvent in the palladium catalyst liquid is not particularly limited, and may be the remainder after adding the above-mentioned components (A), (B), and (C), and other components contained as required.

[0053] The pH of the palladium catalyst solution of the present invention is not particularly limited, but is preferably 5 or less, more preferably 3 or less, even more preferably 1 or less, and particularly preferably 0.5 or less. When the upper limit of the pH is within the above range, better nickel plating precipitation can be imparted to the copper surface, and better patterning can be imparted by suppressing the expansion of nickel plating on copper.

[0054] 2. Method for producing palladium catalyst liquid

[0055] The method for producing the palladium catalyst liquid of the present invention is not particularly limited, and the palladium catalyst liquid can be produced by a production method having a step of adding the above-mentioned components (A), (B) and (C), and other components as required, to a solvent.

[0056] In the above step, the components (A), (B) and (C) and other components as required are sequentially added to a solvent to prepare a palladium catalyst solution. The order of adding the components is not particularly limited.

[0057] In the above step, the conditions for preparing the palladium catalyst solution are not particularly limited, and the mixture may be stirred and mixed in a mixing tank or the like at 10 to 40° C. for about 1 to 10 minutes.

[0058] 3. Palladium catalyst imparting method

[0059] The method for imparting a palladium catalyst to a copper surface using the palladium catalyst solution of the present invention is not particularly limited, and examples thereof include a method for imparting a palladium catalyst including a step of immersing a copper plate in the palladium catalyst solution.

[0060] The temperature of the palladium catalyst liquid in the above step is not particularly limited, but is preferably 20 to 40° C., and more preferably 25 to 35° C. By setting the lower limit of the temperature of the palladium catalyst liquid to the above range, the nickel plating precipitation on the copper surface can be further improved, and the nickel plating expansion can be suppressed to show a more excellent pattern property. By setting the upper limit of the temperature of the palladium catalyst liquid to the above range, the corrosion of copper can be further suppressed.

[0061] The immersion time in the above step is not particularly limited, but is preferably 0.5 to 5 minutes, and more preferably 1 to 3 minutes. By setting the lower limit of the immersion time to the above range, the nickel plating precipitation on the copper surface can be further improved, and the nickel plating expansion can be suppressed to show a better pattern. By setting the upper limit of the immersion time to the above range, the corrosion of copper can be further suppressed.

[0062] Example

[0063] Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples.

[0064] In addition, the raw materials used in Examples and Comparative Examples are as follows.

[0065] (A) Organic acid: 70% methanesulfonic acid

[0066] (B) Chloride: Sodium chloride

[0067] (C) Palladium salt: palladium sulfate (Examples and Comparative Examples)

[0068] The above raw materials were added to water as a solvent in the amounts shown in Table 1, respectively, and stirred in a mixing tank to prepare palladium catalyst solutions of Examples and Comparative Examples.

[0069] The obtained palladium catalyst liquid was subjected to the following tests to evaluate its characteristics.

[0070] (Electroless Nickel Plating Solution)

[0071] As an electroless nickel plating solution, a product name: ICP NICORON FPF manufactured by OKUNO CHEMICAL INDUSTRY CO., LTD. was prepared.

[0072] (Plating precipitation)

[0073] As the electroless plating target material, a micro copper pad ( A BGA (Ball Grid Array: Ball Grid Array) resin substrate with 30 pads. Acid degreasing and soft etching are performed on the electroless plating object material. Then, the catalyst is imparted using the palladium catalyst solution of the embodiment and the comparative example. Then, electroless nickel plating is performed at 84°C and 20 minutes using the electroless nickel plating solution prepared as described above, and the evaluation is performed according to the following evaluation criteria. Among them, as long as the evaluation is 0, it can be evaluated that it can be used without problems in actual use.

[0074] ○: No precipitation at all

[0075] △: Only slightly observed no precipitation

[0076] ×: A large amount of precipitation occurred but no precipitation occurred (pattern property)

[0077] As the object material of electroless plating, a BGA resin substrate with fine wiring (L / S=50 / 50μm) on a resin substrate is prepared. Acid degreasing and soft etching are performed on the object material of electroless plating. Next, the palladium catalyst solution of the embodiment and the comparative example is used for catalyst imparting treatment. Next, using the electroless nickel plating solution prepared as described above, electroless nickel plating of a wiring pattern of L / S=50 / 50μm is performed at 84°C and 20 minutes. The wiring pattern portion of L / S=50 / 50μm after nickel plating is observed under a microscope (1000 times) to observe whether there is expansion of electroless nickel plating outside the wiring pattern, and the evaluation is performed according to the following evaluation criteria. Among them, as long as the evaluation is 0, it can be evaluated as being able to be used without problems in actual use.

[0078] ○: No plating expansion at all

[0079] △: Only a slight expansion of the plating was observed

[0080] ×: Large amount of plating expansion occurs (local corrosion of copper)

[0081] As the material for electroless plating, a BGA resin substrate with a micro copper pad of an over-corrosion-resistant type on a resin substrate is prepared. Acid degreasing and soft etching are performed on the material for electroless plating. Next, the palladium catalyst solution of the embodiment and the comparative example is used for catalyst imparting treatment. Next, electroless nickel plating is performed at 84°C and 20 minutes using the electroless nickel plating solution prepared as described above. For the nickel-plated film, a cross-section observation of the Cu-Ni interface is performed using a FIB device (10,000 times) to observe whether there is local corrosion to the Cu layer, and the evaluation is performed according to the following evaluation criteria. Among them, as long as the evaluation is 0, it can be evaluated as being able to be used without problems in actual use.

[0082] ○: No local corrosion at all

[0083] △: Only slight local corrosion was observed

[0084] ×: Local corrosion occurs in large quantities

[0085] The results are shown in Table 1.

[0086] [Table 1]

[0087]

Claims

1. A palladium catalyst liquid, characterized in that: Contains (A) an organic acid, (B) a chloride and (C) a palladium salt.

2. The palladium catalyst liquid as claimed in claim 1, wherein: The organic acid is at least one selected from the group consisting of organic sulfonic acid, organic carboxylic acid and organic phosphonic acid.

3. The palladium catalyst liquid according to claim 1 or 2, wherein: The content of the organic acid is 10-250 g / L.

4. The palladium catalyst liquid according to claim 1 or 2, wherein: The chloride is at least one selected from the group consisting of sodium chloride, potassium chloride, ammonium chloride and calcium chloride.

5. The palladium catalyst liquid according to claim 1 or 2, wherein: The content of the chloride is 3-50 g / L.

6. The palladium catalyst liquid according to claim 1 or 2, wherein: The palladium salt is at least one selected from palladium sulfate, palladium chloride, palladium oxide, palladium iodide, palladium bromide, palladium nitrate, palladium acetate, tetraamminepalladium chloride, dinitrodiamminepalladium and dichlorodiethylenediaminepalladium.

7. The palladium catalyst liquid according to claim 1 or 2, wherein: The content of the palladium salt is 1-100 mg / L.

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