JP5499517B2 - Metal surface treatment method - Google Patents

Description

  The present invention relates to a metal surface treatment method for copper or a copper alloy.

  In the electronic industry field, there is a demand for the surface roughness Rz value of copper or copper alloy to be 0.5 μm or less when the etching amount is in the range of 0.1 μm to 30 μm. Etching is 0.1 to 5 μm for various pre-treatments such as fine wiring smoothing, photoresist laminating and plating, and 5 to 30 μm for half-etching, especially in the process of producing ultra-thin copper-clad laminates. It is preferable that the copper foil is half-etched to 2 μm or less and the thickness tolerance is small and the variation in the processing surface is excellent (Patent Document 1). In response to this requirement, in the conventional etching method, etching proceeds along the metal crystal grain boundary, so it is extremely difficult to finish the surface roughness Rz value smoothly within the etching amount range of 0.1 to 30 μm. It has been said. In particular, since it was difficult to reduce the surface roughness Rz value of the electrolytic copper foil to 0.5 μm or less with an etching amount of 1 μm or less, the treatment method of the present invention is very useful in the manufacturing process of electronic parts and decorative products. It is.

  As a method of smoothing the surface of copper and copper alloy by chemical polishing, generally, an oxide film is once formed on the surface of copper and copper alloy with an inorganic acid such as sulfuric acid and hydrogen peroxide. There is a method of dissolving and removing the oxide film with sulfuric acid. Since this method is a two-step process and the work process becomes complicated, the surface can be improved by a single process without forming an oxide film with sulfuric acid, hydrogen peroxide, and phosphoric acid. Has been proposed (Patent Document 2).

  However, the brightened surface state of copper and copper alloy obtained by this method is particularly susceptible to the influence of concentration fluctuations of the components contained in the surface treatment liquid, so depending on the concentration fluctuation, the average value of the surface roughness Rz value There were problems such as large variations. Further, an etching solution having a composition of hydrogen peroxide-sulfuric acid-aliphatic amines-azoles-chlorine ions has been proposed as an etching solution, but smoothing treatment is not sufficient with a low etching amount of 1 μm or less (Patent Document 3). ).

JP 2004-165411 A JP-A-8-199376 Japanese Patent Laid-Open No. 2005-15860

  In the present invention, the surface roughness of the copper or copper alloy is within a range of 0.1 to 30 μm, preferably 0.1 to 20 μm, more preferably 0.1 to 10 μm, and particularly preferably 0.2 to 8 μm. The thickness Rz is smoothed to 0.5 μm or less, preferably 0.4 μm or less, and there is little influence on the surface state due to fluctuations in the component concentration in the polishing liquid during continuous use, and a stable smooth surface over time can be obtained. The purpose is to provide a processing method.

As a result of intensive studies on the above problems, the present inventors have (a) hydrogen peroxide, (b) inorganic acid or organic acid, (c) azoles, (d) halogen ions, and (e) silver ions. Immersion treatment or spray treatment was performed with an aqueous solution containing the above. In the case of spray treatment, it was found that by setting the spray pressure within the range of 0.01 to 0.2 MPa, the copper or copper alloy can be smoothed with an etching amount of 0.1 μm to 30 μm, and the present invention was completed. I came to let you.
That is, the present invention is as follows.
1. (A) hydrogen peroxide 1 g / L to 300 g / L, (b) inorganic acid or organic acid, 1 g / L to 100 g / L, (c) azoles 0.001 g / L to 30 g / L, (d) halogen A metal surface treatment method for performing copper metal surface treatment using a treatment liquid comprising 0.001 ppm to 3 ppm of ions and (e) 0.001 ppm to 3 ppm of silver ions.
2. (A) hydrogen peroxide 1 g / L to 300 g / L, (b) inorganic acid or organic acid 1 g / L to 100 g / L, (c) azoles 0.001 g / L to 30 g / L, (d) halogen ion A method of spraying a copper metal surface treatment using a treatment liquid comprising 0.001 ppm to 3 ppm and (e) 0.001 ppm to 3 ppm of silver ions, wherein the pump pressure is within a range of 0.01 to 0.5 MPa. With a discharge amount of 2 L to 500 L / min, the etching amount of the copper metal surface is 0.1 μm to 30 μm, the surface roughness (Rz value) is 0.5 μm or less, and the surface roughness (Rz value) / etching amount is 0.01 to 1. A metal surface treatment method by spray treatment.
3. (B) one or more inorganic acids are selected from sulfuric acid, phosphoric acid, and nitric acid, an organic acid is one or more selected from malic acid, citric acid, and glycolic acid, and (c) azoles are 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 5-methylbenzotriazole, 1H-1,2,3-methylbenzotriazole, 1H-1, 2,3,4-tetrazole, 1H-5-amino-1,2,3,4-tetrazole, 1H-1,2,3-triazole, 1H-1,2,3-benzotriazole, 1H-5-methyl -1,2,3,4-tetrazole, imidazole, and pyrazole, and (d) a halogen ion is a chlorine ion, a bromine ion, or an iodine A hydrogen ion, (e) the first term copper or metal surface treatment method of the copper alloy, wherein the silver ions are silver chloride or silver nitrate.
4). (B) one or more inorganic acids are selected from sulfuric acid, phosphoric acid, and nitric acid, an organic acid is one or more selected from malic acid, citric acid, and glycolic acid, and (c) azoles are 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 5-methylbenzotriazole, 1H-1,2,3-methylbenzotriazole, 1H-1, 2,3,4-tetrazole, 1H-5-amino-1,2,3,4-tetrazole, 1H-1,2,3-triazole, 1H-1,2,3-benzotriazole, 1H-5-methyl -1,2,3,4-tetrazole, imidazole, and pyrazole, and (d) a halogen ion is a chlorine ion, a bromine ion, or an iodine A hydrogen ion, (e) metal surface treatment method according to spraying of the second term, wherein the silver ions is silver chloride or silver nitrate.

  The surface treatment agent of the present invention enables smoothing with a small amount of etching, which has been difficult in the past, and can greatly improve the accuracy of automatic appearance inspection of fine copper wiring. Further, the adhesiveness of the resist can be improved by a pretreatment with a small etching amount. Furthermore, the appearance after plating such as gold plating is improved by a pretreatment with a small etching amount. This is a technique that enables a surface roughness Rz value of 0.5 μm or less even in half etching.

The SEM image which etched the copper circuit board of Example 1 0.5 micrometer is shown. The SEM image which etched the copper circuit board of the comparative example 1 by 0.5 micrometer is shown. The SEM image which etched the copper circuit board of the comparative example 2 by 0.5 micrometer is shown. The SEM image which etched the copper circuit board of the comparative example 3 by 0.5 micrometer is shown. The SEM image which etched the copper circuit board of the comparative example 4 by 0.5 micrometer is shown. 2 shows an unprocessed SEM image of a copper circuit board.

Hereinafter, the present invention will be described in more detail, but the present invention is not limited to the following description.
The smoothing treatment of the metal surface by the metal surface treatment of copper and copper alloy according to the present invention includes (a) hydrogen peroxide, (b) inorganic acid or organic acid, (c) azoles, (d) halogen ions and (E) Processing is performed using an etching solution containing silver ions.

(A) As the hydrogen peroxide, a commercially available product having a concentration of 31 to 60% by mass is usually used. For example, industrial hydrogen peroxide or high-purity hydrogen peroxide manufactured by Mitsubishi Gas Chemical Co., Ltd. is effectively used.
(B) As the inorganic acid, sulfuric acid, phosphoric acid and nitric acid can be used, and sulfuric acid is particularly preferably used. The organic acid is malic acid, citric acid, glycolic acid, tartaric acid, or succinic acid, preferably citric acid or glycolic acid, and particularly preferably malic acid.
(C) azoles are 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 5-methylbenzotriazole, 1H-1,2,3-methyl Benzotriazole, 1H-1,2,3,4-tetrazole, 1H-5-amino-1,2,3,4-tetrazole, 1H-1,2,3-triazole, 1H-1,2,3-benzo Triazole, 1H-5-methyl-1,2,3,4-tetrazole, imidazole and pyrazole, preferably 5-phenyl-1H-tetrazole and 5-methyl-1H-tetrazole, particularly preferably 5 -Amino-1H-tetrazole.
(D) Halogen ions are chlorine ions, bromine ions and iodine ions, preferably chlorine ions and bromine ions, and particularly preferably chlorine ions.
(E) The silver ion is preferably a compound that dissociates silver ions in an aqueous solution such as silver chloride or silver nitrate.

(A) The addition amount of hydrogen peroxide is 1 g / L to 300 g / L, preferably 10 g / L to 200 g / L, and particularly preferably 15 g / L to 100 g / L.
(B) The concentration of the inorganic acid or organic acid is 1 g / L to 100 g / L, preferably 10 g / L to 50 g / L, and particularly preferably 20 g / L to 30 g / L.
(C) The concentration of azoles is 0.001 g / L to 30 g / L, preferably 0.005 g / L to 1 g / L, and particularly preferably 0.01 g / L to 0.1 g / L. .
(D) The concentration of halogen ions is 0.001 ppm to 3 ppm, preferably 0.01 ppm to 2 ppm, and particularly preferably 0.03 ppm to 1 ppm.
(E) The concentration of silver ions is 0.001 ppm to 3 ppm, preferably 0.01 ppm to 2 ppm, and particularly preferably 0.03 ppm to 1 ppm.

  The method for chemically polishing copper and copper alloys using the chemical polishing liquid of the present invention is not particularly limited, but includes a spray method using a spray etching machine, oscillation in an etching tank, an immersion method by pump circulation, etc. Can be processed in any way. Although there is no restriction | limiting in particular also in the temperature of a chemical polishing liquid, Although it can set arbitrarily according to the melt | dissolution rate desired from the range of 10-50 degreeC, 15-45 degreeC is more preferable, Especially 20-40 degreeC Is preferred.

  In the case of an etching operation using a spray etching machine, the spray pressure at the nozzle outlet is in the range of 0.01 to 0.5 MPa, preferably 0.05 to 0.4 MPa, more preferably 0.1 to 0. .3 MPa. The pump discharge amount of the etching solution is 2 to 500 L / min, preferably 4 to 400 L / min, and more preferably 10 to 350 L / min.

Reagent (source);
・ Hydrogen peroxide: Industrial 60% hydrogen peroxide (Mitsubishi Gas Chemical)
・ Sulfuric acid; reagent special grade 47% sulfuric acid (Wako Pure Chemical Industries)
・ Phosphoric acid; Special grade 85% sulfuric acid (Wako Pure Chemical Industries)
・ Nitric acid; reagent special grade 60% sulfuric acid (Wako Pure Chemical Industries)
-5-amino-1H-tetrazole; first grade reagent (Wako Pure Chemical Industries)
・ Silver ion; reagent special grade silver nitrate (Wako Pure Chemical Industries)
・ Chlorine ion; reagent special grade sodium chloride (Wako Pure Chemical Industries)
・ Copper: Reagent special grade copper sulfate pentahydrate (Wako Pure Chemical Industries, Ltd.)
Surface roughness (Rz value) evaluation method;
Measured with a laser microscope (OLS4000: manufactured by Olympus). The difference between the average of the height from the highest to the fifth and the average value of the depth of the valley from the deepest to the fifth is shown by the Rz value at the portion where the sectional curve is extracted by the reference length.
SEM observation of copper surface;
Images were taken at a magnification of 2,000 with an electron microscope VE-8800S manufactured by Keyence Corporation.
Method for measuring copper etching amount;
The mass method was calculated by the following formula.
Etching amount = (mass before treatment−mass after treatment) / (treatment area × 8.92)
Spray etching equipment;
Using an actual machine intended for mass production, the copper wiring substrate and the entire copper foil substrate were processed at a spray pressure of 0.2 MPa, a pump discharge rate of 350 L / min, and a processing liquid temperature of 30 ° C.
As the spray nozzle, 1/4 MISJJX030 PP-FRPP manufactured by Ikeuchi Co., Ltd. was used.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.
Examples 1 to 4
The composition of the aqueous solution was prepared assuming an actual solution, and an etching solution according to the present invention was prepared.
The blending amounts are summarized in Table 1. The treatment was performed using a substrate on which a copper circuit was formed as a test substrate while keeping the temperature of the etching solution at 30 ° C., and the treatment was performed with a spray pressure of 0.05 MPa and a liquid amount of 200 L. A processed sample having an etching amount of 0.5 μm was prepared, and the surface roughness (Rz) was measured.

Example 5
Using a copper clad laminate, an etching sample having a thickness of 5 μm was prepared under the above-described processing conditions, and the surface roughness (Rz) was measured. The blending amounts are shown in Table 1.

Comparative Examples 1 to 4
The board | substrate which formed the copper circuit on the process conditions same as Example 1- Example 4 was processed. The blending amounts are shown in Table 1.

Comparative Example 5 to Comparative Example 7
Using a copper-clad laminate, an etching sample of 5 μm was prepared under the processing conditions of Examples 1 to 4, and the surface roughness (Rz) was measured. The blending amounts are shown in Table 1.

  Table 2 shows the measurement results of surface roughness (Rz value), surface roughness (Rz value) / etching amount of Examples 1 to 5 and Comparative Examples 1 to 7.

    As shown in Table 2 and FIGS. 1 to 6, the treatment method of the present invention resulted in excellent smoothed copper circuit plates and copper clad laminates.

  (A), (b) and (c) Compound for Surface Treatment Liquid and Surface Treatment Method Containing Compound (a), (b), (c), (d) and (e) Compound Surface treatment solution and surface treatment method (Comparative Example 1), (a), (b), (c), and (d) Surface treatment solution and compound (Comparative Example 2), (a) , (B), (c) and (e) surface treatment liquid and surface treatment method (Comparative Example 3), (a), (b), and surface treatment method containing phosphoric acid (Comparative Example 4) The obtained surface treatment increased the surface roughness Rz value in the automatic appearance inspection.

  According to a preferred aspect of the present invention, the metal surface treatment liquid and the metal surface treatment method of the present invention enable smoothing of copper and copper alloys with a small etching amount, which has been difficult in the past, and is industrially useful.

Claims (4)

(A) Hydrogen peroxide 1 g / L to 100 g / L, (b) Inorganic or organic acid, 1 g / L to 30 g / L, (c) Azoles 0.001 g / L to 0.1 g / L , (d) halogen ions 0.001ppm~ 1 ppm and, (e) rows that have a copper metal surface treatment using the treating solution of silver ions 0.001Ppm～1ppm, and copper metal surface roughness (Rz value) Is a treatment method for smoothing a metal surface , characterized by being 0.5 μm or less . (A) hydrogen peroxide 1 g / L to 100 g / L, (b) inorganic or organic acid 1 g / L to 30 g / L, (c) azoles 0.001 g / L to 0.1 g / L, (D) A method of spraying a copper metal surface treatment using a treatment liquid comprising 0.001 ppm to 1 ppm of halogen ions and (e) 0.001 ppm to 0.05 ppm of silver ions, the spray pressure being 0.01 Within the range of ~ 0.2 MPa, pump discharge rate 2 L to 350 L / min, etching amount of copper metal surface 0.1 μm to 8 μm, surface roughness (Rz value) 0.5 μm or less, surface roughness (Rz Value) / Processing method for smoothing the metal surface by spraying, wherein the etching amount is 0.01 to 1. (B) one or more inorganic acids are selected from sulfuric acid, phosphoric acid, and nitric acid, an organic acid is one or more selected from malic acid, citric acid, and glycolic acid, and (c) azoles are 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 5-methylbenzotriazole, 1H-1,2,3-methylbenzotriazole, 1H-1, 2,3,4-tetrazole, 1H-5-amino-1,2,3,4-tetrazole, 1H-1,2,3-triazole, 1H-1,2,3-benzotriazole, 1H-5-methyl -1,2,3,4-tetrazole, imidazole, and pyrazole, and (d) a halogen ion is a chlorine ion, a bromine ion, or an iodine A hydrogen ion, the processing method for smoothing (e) copper or metal surface of a copper alloy according to claim 1, wherein the silver ions, wherein the silver chloride or silver nitrate. (B) one or more inorganic acids are selected from sulfuric acid, phosphoric acid, and nitric acid, an organic acid is one or more selected from malic acid, citric acid, and glycolic acid, and (c) azoles are 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 5-methylbenzotriazole, 1H-1,2,3-methylbenzotriazole, 1H-1, 2,3,4-tetrazole, 1H-5-amino-1,2,3,4-tetrazole, 1H-1,2,3-triazole, 1H-1,2,3-benzotriazole, 1H-5-methyl -1,2,3,4-tetrazole, imidazole, and pyrazole, and (d) a halogen ion is a chlorine ion, a bromine ion, or an iodine A hydrogen ion, the processing method for smoothing a metal surface by spray treatment according to claim 2, characterized in that the (e) silver ion of silver chloride or silver nitrate.

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