KR20080066580A - Method for surface treatment of aluminum or aluminum alloy - Google Patents

Abstract

A method for surface treatment of aluminum or aluminum alloy is provided to obtain a high adhesion property of the electroless copper plating film by forming an electroless copper plating film on an electroless nickel film in a state that the electroless nickel film is provided with good catalytic properties without excessively eroding the electroless nickel film. As a method for surface treatment of aluminum or aluminum alloy by forming an electroless nickel plating film on the aluminum or aluminum alloy of a treatment object having aluminum or aluminum alloy at least on a surface thereof, and forming an electroless copper plating film on the electroless nickel plating film, the method comprises: a nickel plating process of removing an aluminum oxide film formed on a surface layer of the aluminum or aluminum alloy of the treatment object, and forming an electroless nickel plating film on the aluminum or aluminum alloy; an intermediate plating process of forming an intermediate plating film of Ag, Au, Pd, Pt, Rh or an alloy thereof on a surface of the electroless nickel plating film by displacement plating or electroless plating; and a copper plating process of forming an electroless copper plating film on a surface of the intermediate plating film.

Description

Surface treatment method of aluminum or aluminum alloy {METHOD FOR SURFACE TREATMENT OF ALUMINUM OR ALUMINUM ALLOY}

The present invention relates to a surface treatment method of aluminum or an aluminum alloy, and more particularly, to a surface treatment method of aluminum or an aluminum alloy when UBM (under bump metal) or bump is formed by plating on a wafer.

Conventionally, as a method of forming UBM or bump on a silicon wafer, a method of forming a zinc film by performing zinc substitution treatment on a patterned aluminum thin film electrode on a wafer, and then forming a bump by electroless nickel plating, Method of forming bumps by electroless nickel plating after palladium treatment instead of zinc substitution treatment, or forming bumps by self-catalyzed electroless nickel plating after directly replacing the surface of aluminum thin film electrode with nickel And the like are used.

In addition, the UBM or bump in which the electroless nickel plated film is formed by such a method may be further subjected to electroless copper plating on the electroless nickel plated film in order to improve the electrical characteristics, particularly the electrical resistance. . In this case, since the electroless nickel film has no catalytic property and cannot be electroless copper plated directly on the electroless nickel film, a copper substitution treatment for imparting catalytic property to the electroless nickel film has been conventionally performed.

However, this copper substitution process is easy to erode the electroless nickel film, and as a result, the base material (aluminum or aluminum alloy) is attacked (erosion), and as a result, the adhesion of the electroless copper plating film formed by copper substitution treatment is lowered. There was a problem.

(Summary of invention)

The present invention has been made in view of the above circumstances, and an electroless nickel plated film is formed on an aluminum or aluminum alloy, and an electroless copper plated film is formed on the electroless nickel plated film to thereby provide a surface of the aluminum or aluminum alloy. At the time of treatment, the surface treatment of aluminum or aluminum alloy which does not excessively erode the electroless nickel film, imparts good catalytic properties to form an electroless copper plated film, and can provide high adhesion of the electroless copper plated film. It is an object to provide a method.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to achieve the said objective, the present inventors formed an electroless nickel plating film on aluminum or an aluminum alloy, and also formed an electroless copper plating film on this electroless nickel plating film, and made it an aluminum or aluminum alloy. When treating the surface of, an intermediate plating film of Ag, Au, Pd, Pt, Rh or their alloys is formed on the surface of the electroless nickel plated film by substitution plating or electroless plating, thereby forming an electroless copper plated film. By forming the present invention, it has been found that the electroless copper plating film can be formed by imparting good catalytic properties, and the obtained electroless copper plating film also has high adhesiveness.

Accordingly, the present invention provides a surface treatment method of the aluminum or aluminum alloy described below.

(One):

Of an aluminum or aluminum alloy which forms an electroless nickel plated film on at least the aluminum or aluminum alloy of the workpiece having at least an aluminum or aluminum alloy on its surface, and also forms an electroless copper plated film on the electroless nickel plated film. As a surface treatment method,

A nickel plating process of removing an aluminum oxide film formed on the aluminum or aluminum alloy surface layer of the workpiece and forming an electroless nickel plating film on the aluminum or aluminum alloy;

An intermediate plating step of forming an intermediate plating film of Ag, Au, Pd, Pt, Rh or their alloys by substitution plating or electroless plating on the surface of the electroless nickel plating film, and

Copper plating process of forming an electroless copper plating film on the surface of the said intermediate plating film

Surface treatment method of aluminum or aluminum alloy comprising a.

(2):

The nickel plating process is immersed in the removal liquid for an aluminum oxide film containing aluminum and the metal which can be substituted, and removes the aluminum oxide film, and forms the substitution metal layer of the aluminum and metal replaceable in the removal liquid. Process,

Removing this substituted metal layer with an acidic liquid having an oxidizing action, and

Removing the substitution metal layer to form an electroless nickel plating film on the exposed aluminum or aluminum alloy

Surface treatment method as described in (1) characterized by including the.

(3):

The surface treatment method according to (2), wherein the removal liquid for aluminum oxide film contains a salt of aluminum, a metal which can be substituted, and an acid.

(4):

The removal liquid for aluminum oxide film contains the salt or oxide of a metal which can be substituted with aluminum, the solubilizer of the ion of this metal, and an alkali, and pH is 10-13.5, The surface as described in (2) characterized by the above-mentioned. Treatment method.

(5):

The surface treatment method according to (3) or (4), wherein the removal liquid for aluminum oxide film further contains a surfactant.

According to the present invention, it is a good catalyst when forming an electroless nickel plated film on aluminum or an aluminum alloy, and forming an electroless copper plated film on the electroless nickel plated film to treat the surface of the aluminum or aluminum alloy. By providing a property, an electroless copper plating film can be formed, and the obtained electroless copper plating film will have high adhesiveness.

(Detailed Description of the Invention)

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The surface treatment method of this invention forms an electroless nickel plating film on the said aluminum or aluminum alloy of the to-be-processed object which has an aluminum or aluminum alloy at least on the surface, and also makes an electroless copper plating film on this electroless nickel plating film. In the surface treatment method of forming aluminum or aluminum alloy,

A nickel plating process of removing an aluminum oxide film formed on the aluminum or aluminum alloy surface layer of the workpiece and forming an electroless nickel plating film on the aluminum or aluminum alloy;

An intermediate plating step of forming an intermediate plating film of Ag, Au, Pd, Pt, Rh or their alloys by substitution plating or electroless plating on the surface of the electroless nickel plating film, and

Copper plating process of forming an electroless copper plating film on the surface of the said intermediate plating film

It will include. Hereinafter, each said process is demonstrated.

[Nickel Plating Process]

In the present invention, the aluminum oxide film formed on the aluminum or aluminum alloy surface layer of the workpiece is removed and an electroless nickel plated film is formed on the aluminum or aluminum alloy. A conventionally known method is used for removing the aluminum oxide film. Applicable, the aluminum oxide film is removed to form an electroless nickel plated film on the exposed aluminum or aluminum alloy.

In this case, the to-be-processed object is immersed in the removal liquid for aluminum oxide films containing aluminum and a replaceable metal, forming the substituted metal layer of aluminum and a replaceable metal contained in a removal liquid, removing an aluminum oxide film, and replacing this substituted metal layer It is also possible to remove with an acidic liquid having an oxidizing action, and to remove the substituted metal layer to form an electroless nickel plating film on the exposed aluminum or aluminum alloy.

As the removal liquid for aluminum oxide films, it contains a salt of aluminum and a metal which can be substituted, an acid, and preferably contains a surfactant (acid removal liquid), or a salt or an oxide of a metal which can be substituted with aluminum, and an ion of this metal. Solubilizing agent, an alkali, and preferably a surfactant, and having a pH of 10 to 13.5 (alkaline removal liquid) can be suitably used.

(Acid remover)

The metal constituting the metal salt contained in the acidic removing liquid is not particularly limited as long as it is a metal which can be substituted with aluminum, but is preferably a metal having a smaller ionization tendency than aluminum. For example, zinc, iron, cobalt, nickel, tin, lead, copper Mercury, silver, platinum, gold, palladium, etc. are mentioned, As said metal salt, water-soluble salts, such as nitrate and sulfate of these metals, are mentioned. In particular, sulphate is preferred for reasons such as stability of the removal solution and less aggressiveness to aluminum or aluminum alloy materials. These may be used individually by 1 type or in combination of 2 or more types. Among them, since silver, nickel and copper are less likely to be precipitated at other sites, they are preferable. Especially, since copper and silver have a much smaller ionization tendency than aluminum, substitution reaction tends to proceed more, and etching time can be shortened. Suitable.

Although it does not restrict | limit especially as a density | concentration of the metal salt used for an acidic removal liquid, Usually, it is 1 ppm or more as a metal amount, Preferably it is 10 ppm or more, and as an upper limit, it is 10,000 ppm or less normally, Preferably it is 5,000 ppm or less. If the concentration of the metal salt is too small, it may not be sufficiently substituted with the base aluminum, or it may be necessary to supply the metal salt. On the other hand, if the concentration is too large, in the case where aluminum or aluminum alloy is an electrode patterned on the wafer, it may impinge on a member other than the aluminum or aluminum alloy, or may be blown onto the member other than the aluminum or aluminum alloy. It may precipitate.

The acid contained in the acidic removal liquid is not particularly limited, but it is required to be an acid that dissolves the oxide film. Examples thereof include sulfuric acid, phosphoric acid, hydrochloric acid, hydrofluoric acid, and the like. You may use together. Among them, sulfuric acid is preferred from the viewpoints of stability of the removal liquid and low aggression against aluminum or aluminum alloy materials.

The concentration in the acid removal liquid is not particularly limited either, but is usually 10 g / L or more, preferably 15 g / L or more, and usually 500 g / L or less, preferably 300 g / L or less as an upper limit. If the acid concentration is too small, the oxide film does not melt and there is no effect. On the other hand, if the concentration is too large, a member other than the aluminum or aluminum alloy base may be impaired.

(Alkaline removal liquid)

The metal constituting the metal salt or metal oxide contained in the alkaline removing liquid is not particularly limited as long as it is a metal which can be substituted with aluminum, but is preferably a metal having a smaller ionization tendency than aluminum. For example, manganese, zinc, iron, cobalt, nickel, Tin, lead, copper, mercury, silver, platinum, gold, palladium, etc. are mentioned, As said metal salt, water-soluble salts, such as nitrate and sulfate of these metals, are mentioned. Especially, since the reduction potential difference with the manganese and the aluminum containing zinc is small, it is preferable.

The concentration of the metal salt or metal oxide used in the alkaline removing liquid is not particularly limited, but is usually 1 ppm (mg / L) or more, preferably 10 ppm (mg / L) or more, and an upper limit of 10,000 ppm (mg / L). ), Preferably 5,000 ppm (mg / L) or less. If the concentration of the metal salt or metal oxide is too small, it may not be sufficiently substituted with the base aluminum, or it may be necessary to supply the metal salt or metal oxide. On the other hand, if the concentration is too large, in the case where aluminum or aluminum alloy is an electrode patterned on the wafer, it may impinge on a member other than the aluminum or aluminum alloy, or may be blown onto the member other than the aluminum or aluminum alloy. It may precipitate.

Although it does not restrict | limit especially as a solubilizer of the metal ion contained in alkaline removal liquid, A conventional complexing agent and a chelating agent can be used. Specifically, hydroxycarboxylic acids and salts thereof, such as glycolic acid, lactic acid, malic acid, tartaric acid, citric acid, gluconic acid, heptogluconic acid, glycine, aminodicarboxylic acid, nitriloacetic acid, EDTA, and hydroxy Aminocarboxylic acids and salts thereof such as oxyethylethylenediamine triacetic acid, diethylenetriamine pentaacetic acid, and polyaminopolycarboxylic acid, and phosphorous acid chelating agents such as HEDP, aminotrimethylphosphonic acid, and ethylenediaminetetramethylphosphonic acid; Amine chelating agents such as salts, ethylenediamine, diethylenetriamine, and triethylenetetramine can be used.

The concentration of the solubilizer used in the alkaline removal liquid is not particularly limited, but the total concentration of the solubilizer relative to the metal salt used is 0.5 to 10 (molar ratio), preferably 0.8 to 5 (molar ratio).

The alkali contained in the alkaline removal liquid is not particularly limited, but it is required to be an alkali (base) for dissolving an oxide film, and for example, alkali metals such as LiOH, NaOH, KOH, or trimethylammonium hydroxide (TMAH), choline, etc. Hydroxides of quaternary ammonium and the like can be used. In addition, the addition amount of alkali is the quantity which makes pH of a removal liquid into a prescribed range, ie, the pH which is 10-13.5, Preferably it is 11-13. When pH is less than 10, there exists a possibility that a dissolution rate may fall remarkably, and when pH exceeds 13.5, a dissolution rate may become too fast and it may not be able to control.

It is suitable that the said oxide film removal liquid contains surfactant from a viewpoint of providing wettability to both an acidic removal liquid and an alkaline removal liquid. Although it does not specifically limit as surfactant used, For example, Nonionic surfactants, such as polyethyleneglycol and a polyoxyethylene-oxypropylene block copolymerization type | mold active agent, In addition, anionic type and cationic type surfactant are mentioned, for example. In view of the uniformity, the nonionic and anionic types are preferred. These may be used individually by 1 type, or may use 2 or more types together.

For example, when polyethyleneglycol is used as the surfactant, the molecular weight thereof is not particularly limited, but is usually 100 or more, preferably 200 or more, and usually 20,000 or less, preferably 6,000 or less. When molecular weight is too large, solubility may worsen, on the other hand, when molecular weight is too small, wettability may not be provided. In addition, a commercial item can be used as polyethylene glycol.

The concentration in the removal liquid of the surfactant is not particularly limited, but is usually 1 ppm or more (mg / L), preferably 10 ppm (mg / L) or more, and usually 5,000 ppm (mg / L) or less as an upper limit, preferably 2,000 ppm (mg / L) or less. When the concentration in the removal liquid of the surfactant is too small, the wettability effect obtained by the addition of the surfactant may be low. On the other hand, when the concentration is too large, the substitution metal precipitates on a member other than aluminum or an aluminum alloy. There is.

In addition, it is preferable that both the acidic removal liquid and the alkaline removal liquid are prepared as an aqueous solution from the viewpoint of the safety of the operation. However, other solvents such as methanol, ethanol, IPA, etc. may be used or mixed with water. It is also possible to use a solvent. In addition, these solvent may be used individually by 1 type or in combination of 2 or more types.

The immersion conditions when immersing the workpiece having aluminum or aluminum alloy in the removal liquid are not particularly limited, and may be appropriately set in consideration of the thickness of the aluminum oxide film to be removed, etc., usually 1 minute or more, preferably It is 20 minutes or less normally as an upper limit for 2 minutes or more, Preferably it is 15 minutes or less. If the immersion time is too short, the substitution may not proceed and the removal of the oxide film may be insufficient. On the other hand, if the immersion time is too long, the removal liquid may penetrate through the small holes of the substituted metal layer, and aluminum or aluminum alloy may elute. There is concern.

The temperature at the time of immersion is not particularly limited, but is usually 20 ° C or higher, preferably 25 ° C or higher, and usually 100 ° C or lower, preferably 95 ° C or lower. If the immersion temperature is too low, the oxide film may not be dissolved. On the other hand, if the immersion temperature is too high, members other than aluminum or an aluminum alloy may be impeded. In addition, at the time of immersion, it is preferable to perform liquid stirring and rocking of the to-be-processed object from a viewpoint of processing uniformly.

In the case where the removal solution for an oxide film is used, the aluminum oxide film is removed and a substituted metal layer of aluminum and a replaceable metal is formed. The substituted metal layer can be removed by an acidic liquid having an oxidizing action, and the removed aluminum layer is removed. Alternatively, plating may be performed on the aluminum alloy directly or after performing zinc substitution treatment or palladium treatment.

When removing the substituted metal layer with an acidic liquid having an oxidizing action, an acidic liquid having an oxidizing action is used in view of alleviating the reactivity with the underlying aluminum or aluminum alloy. In this case, as an acidic liquid having an oxidizing action, an oxidizing agent such as hydrogen peroxide, sodium persulfate, and an acid having an oxidizing action such as nitric acid or an aqueous solution thereof, or an acid or an aqueous solution having no oxidation action such as sulfuric acid or hydrochloric acid may be used. One kind or two or more kinds such as ammonium sulfate and potassium persulfate are added. In this case, the acid has a function of dissolving the substituted metal, and the oxidant has a function of relieving reactivity to the aluminum or aluminum alloy base. Among the oxidizing agents, hydrogen peroxide is preferable in terms of hydrogen and oxygen, and when reduced, it is water. Sodium persulfate and potassium persulfate are preferable in terms of stability and easy handling.

Here, when nitric acid is used as the acid (and oxidant), the amount of nitric acid in the solution (aqueous solution) is usually 200 ml / L or more, preferably 300 ml / L or more, and usually 1,000 ml / L or less as an upper limit, preferably Is 700 ml / L or less. If the amount of nitric acid is too small, the oxidizing power is low, and the reaction may not stop. In addition, 1,000 ml / L nitric acid is a case where whole quantity is nitric acid.

The amount of the oxidant in the dissolution solution in the case of using the oxidizing agent is usually 50 g / L or more, preferably 75 g / L or more, and usually 500 g / L or less, preferably 300 g / L or less as an upper limit. If the amount of the oxidant is too small, the oxidizing power is low and the reaction may not stop. On the other hand, if the amount is excessively large, the economy may be poor. In this way, the concentrations of acids such as hydrochloric acid and sulfuric acid used together with the oxidizing agent are usually 10 g / L or more, preferably 15 g / L or more, and usually 500 g / L or less, preferably 300 g / L or less as an upper limit. If the concentration of the acid is too small, the substituted metal layer may be difficult to dissolve. On the other hand, if the concentration is too large, there is a risk of eroding members other than aluminum or aluminum alloy. In addition, the acid used here is preferably non-oxidizing, but may be an oxidizing acid such as nitric acid, or may be used by mixing an oxidizing acid with a non-oxidizing acid.

There is no restriction | limiting in particular also as a processing time in this dissolution process, For example, a dissolution process can be performed for 5 to 300 second, As a dissolution process temperature, the conditions of 10-40 degreeC can be employ | adopted, for example. Moreover, during a dissolution process, the to-be-plated object may be stopped or rocked, and liquid stirring may be performed.

An electroless nickel plating film is formed on the exposed aluminum or aluminum alloy by removing the aluminum oxide film. A well-known electroless nickel plating bath can be used for this electroless nickel plating, For example, the electroless nickel plating bath containing nickel sulfate, organic acid (succinic acid, malic acid, citric acid, etc.), sodium hypophosphite, etc. is mentioned. And a commercial plating bath can also be used.

The film thickness of the electroless nickel plating film to be formed is usually about 1 to 20 µm, and the plating temperature and the plating time are selected in accordance with the film thickness of the plating film to be formed, but the plating temperature is usually 50 to 95 ° C and the plating time. Is 5 to 120 minutes.

In addition, electroless nickel plating can be performed directly on the surface of aluminum or aluminum alloy, and electroless nickel plating treatment may be performed after zinc activation treatment, palladium treatment or the like to activate the surface of aluminum or aluminum alloy. do. As such an activation process, it is particularly suitable to form a zinc film on the surface of aluminum or an aluminum alloy by performing zinc substitution treatment, and in particular, alkali zinc substitution treatment, from the viewpoint of improving the adhesion of the plating coating.

Here, as a zinc substitution process, it means using the solution containing a zinc salt specifically, and performing a process which substitutes and deposits zinc. In the case of an alkali zinc substitution process, an alkaline zinc acid solution is used, and as an acidic zinc substitution process, a process which substitutes and deposits zinc using the solution containing an acidic zinc salt is performed, These are well-known This can be done by the method. Moreover, also as a palladium treatment, the process which carries out substitution precipitation of palladium using the solution containing a palladium salt is performed, and can be performed by a well-known method.

[Intermediate Plating Process]

In the present invention, an intermediate plating film of Ag, Au, Pd, Pt, Rh or an alloy thereof is formed on the surface of the electroless nickel plating film formed in the nickel plating step by substitution plating or electroless plating. For this substitutional plating or electroless plating, a known substitutional plating bath or electroless plating bath containing Ag, Au, Pd, Pt or Rh can be used, for example, metals (Ag, Au, Pd, Pt, Ph). Substituted plating baths containing salts, inorganic acids (sulfuric acid, hydrochloric acid, etc.), organic acids (succinic acid, malic acid, citric acid, etc.), metals (Ag, Au, Pd, Pt, Ph) salts, complexing agents (organic acids, EDTA, etc.), An electroless plating bath containing a reducing agent (formic acid, sodium hypophosphite, hydrazine, etc.) etc. can be mentioned, A commercial plating bath can also be used.

The film thickness of the intermediate plating film to be formed is usually 0.005 to 1.0 µm, preferably about 0.01 to 0.5 µm, and the plating temperature and the plating time are selected in accordance with the film thickness of the plating film to be formed. -80 degreeC and plating time are 10 second-10 minutes. By forming an intermediate plating film of Ag, Au, Pd, Pt, Rh or an alloy thereof, and forming an electroless copper plating film by a copper plating process described later, good catalytic properties are imparted to the electroless copper plating film. Can be formed.

[Copper Plating Process]

In this invention, an electroless copper plating film is formed on the surface of the intermediate plating film formed at the said intermediate plating process. A well-known electroless copper plating bath can be used for this electroless copper plating, For example, the electroless copper plating bath containing a copper sulfate, a complexing agent (tartaric acid, EDTA, etc.), formalin, etc. is mentioned, A commercial plating is carried out. You can also use swear words.

The film thickness of the electroless copper plating film to be formed is usually about 0.05 to 10 µm, and the plating temperature and the plating time are selected according to the film thickness of the plating film to be formed, but the plating temperature is usually 20 to 75 ° C. and the plating time. Is 5 minutes to 6 hours.

As a to-be-processed object which has aluminum or an aluminum alloy on the at least surface which this invention targets, even if the to-be-processed object is formed from aluminum or an aluminum alloy, a non-aluminum material (for example, silicon, FRA (base material of a printed circuit board)) The whole or part of the surface of) may be covered with aluminum or an aluminum alloy. Moreover, it is not specifically limited also as the form of this aluminum or aluminum alloy, For example, it can apply favorably to a blank material, a rolling material, a casting material, a film, etc .. In the case where a film of aluminum or aluminum alloy is formed on the surface of the non-aluminum material, the method of forming the film is not particularly limited, but the method of formation is, for example, a vapor deposition method, a sputtering method, an ion plating method, or the like. Plating method is suitable.

As thickness of this film, it is 0.5 micrometer or more, Preferably it is 1 micrometer or more from a viewpoint which reliably remains aluminum or aluminum alloy base material. In addition, the upper limit of the thickness is not specifically limited, Usually, it is 100 micrometers or less.

Further, the component of the film is not particularly limited as long as it is aluminum or an aluminum alloy, but for example, alloys such as Al-Si (Si content of 0.5 to 1.0 wt%) and Al-Cu (Cu content of 0.5 to 1.0 wt%) Applicable also to a film.

(Example)

Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to the following Example.

Example 1

As the plated workpiece, a silicon plate coated with an aluminum layer having a thickness of 5 μm by the sputtering method was used, and the treatment shown in Table 1 was sequentially performed on the aluminum layer. Table 2 shows the results of the evaluation of the properties of the obtained plated film.

process Chemical Condition (One)  Cleaner / Surface Cleaning Epitas MCL-16 ^*  50 ℃ for 5 minutes (2)  Anodized  The following oxide film removal liquid  50 ℃ for 1 minute (3)  Smut removal 50% HNO ₃  20 ℃ for 30 seconds (4)  First Genegate Treatment Epitas MCT-17 ^*  20 ℃ for 10 seconds (5)  Jinkate film removal 50% HNO ₃  20 ℃ 60 seconds (6)  Second Genegate Treatment Epitas MCT-17 ^*  20 ℃ for 30 seconds (7)  Electroless nickel plating Epitas NPR-18 ^*  Film thickness 3㎛ (8)  Substitution gold plating (gold sulfite) Epitas TDS-20 ^*  Film thickness 0.04㎛ (9)  Electroless copper plating Epitas PSP-20 ^*  Film thickness 8㎛

*: Uemurago Bridge Co., Ltd.

Oxidation removal solution: 2 g / L of zinc sulfate as metal salt, 10 g / L of EDTA.2Na as solubilizer, 1 g / L of PEG (polyethylene glycol) -1000 as surfactant, NaOH as alkali, pH of 12.4 Adjusted water solution

Example 2

The substitution gold plating (gold sulfite) of (8) was carried out except substitution gold plating (cyan gold) (chemical liquid: Epitas TDL-20 (manufactured by Uemura Co., Ltd.), conditions: film thickness of 0.05 µm). The treatment was carried out in the same manner as in Example 1. Table 2 shows the results of the evaluation of the properties of the obtained plated film.

Example 3

Example 1 except that the substitution gold plating (gold sulfite) of (8) was electroless Pd plating (chemical solution: Epitas TFP-30 (manufactured by Uemura Co., Ltd.), conditions: film thickness 0.06 μm) The treatment was carried out in the same manner. Table 2 shows the results of the evaluation of the properties of the obtained plated film.

Comparative Example 1

Treatment was performed in the same manner as in Example 1 except that the substitution gold plating (gold sulfite) of (8) was not performed. Table 2 shows the results of the evaluation of the properties of the obtained plated film.

Comparative Example 2

Example 1 except that the substitution gold plating (gold sulfite) of (8) to copper substitution treatment (chemical liquid: 0.5 g / L sulfuric acid (62.5%) 10 g / L), conditions: 20 ℃ 30 seconds) The treatment was carried out in the same manner. Table 2 shows the results of the evaluation of the properties of the obtained plated film.

evaluation Example Comparative example One 2 3 One 2 Appearance of electroless copper plating Good Good Good Bad Good Adhesion Good Good Good - Bad Attack on possession none none none - has exist

-Appearance of an electroless copper plating film: It observed by visual observation and a stereomicroscope, and made unadhered and unstained or unstained defect good.

Adhesiveness: The silicon plate was bent while breaking with the plating film, and it was good that the plating film was broken without being peeled off, and the one peeled between Ni / Cu was defective.

Attack on the body: "None" means that there is no attack (erosion) on the aluminum body, and "there" means that the aluminum body is eroded.

Claims (5)

Of an aluminum or aluminum alloy which forms an electroless nickel plated film on at least the aluminum or aluminum alloy of the workpiece having at least an aluminum or aluminum alloy on its surface, and also forms an electroless copper plated film on the electroless nickel plated film. As a surface treatment method, A nickel plating process of removing an aluminum oxide film formed on the aluminum or aluminum alloy surface layer of the workpiece and forming an electroless nickel plating film on the aluminum or aluminum alloy; An intermediate plating step of forming an intermediate plating film of Ag, Au, Pd, Pt, Rh or their alloys by substitution plating or electroless plating on the surface of the electroless nickel plating film, and Copper plating process of forming an electroless copper plating film on the surface of the said intermediate plating film Surface treatment method of aluminum or aluminum alloy comprising a. The aluminum-substitutable metal replaceable in claim 1, wherein the nickel plating process is immersed in the removal liquid for an aluminum oxide film containing the aluminum and a replaceable metal to remove the aluminum oxide film. Forming a substituted metal layer of Removing this substituted metal layer with an acidic liquid having an oxidizing action, and Removing the substitution metal layer to form an electroless nickel plating film on the exposed aluminum or aluminum alloy Surface treatment method comprising a. 3. The surface treatment method according to claim 2, wherein the removal liquid for aluminum oxide film contains a salt of aluminum and a replaceable metal, and an acid. The said aluminum oxide film removal liquid contains a salt or oxide of a metal which can be substituted with aluminum, the solubilizer of the ion of this metal, and an alkali, pH is 10-13.5 Surface treatment method. The surface treatment method according to claim 3 or 4, wherein the removal liquid for aluminum oxide film further contains a surfactant.