KR101499848B1 - Method for surface treatment of aluminum or aluminum alloy - Google Patents

Abstract

A step of removing an aluminum oxide film formed on a surface layer of aluminum or an aluminum alloy to form an electroless nickel plated film, a step of forming an electroless nickel plated film on the surface of the electroless nickel plated film by substitution plating or electroless plating with Ag, Au, Pd, Pt, An electroless nickel plating film is formed on aluminum or an aluminum alloy by a step of forming an intermediate plating film of Rh or an alloy thereof and a step of forming an electroless copper plating film on the surface of the intermediate plating film, A copper plating film is further formed.

When an electroless nickel plating film is formed on an aluminum or aluminum alloy and an electroless copper plating film is formed on the electroless nickel plating film to treat the surface of the aluminum or aluminum alloy, A copper plating film can be formed, and the resultant electroless copper plating film has high adhesion.

Aluminum, oxide coating, electroless, nickel plating, copper plating, catalytic, adhesion.

Description

METHOD FOR SURFACE TREATMENT OF ALUMINUM OR ALUMINUM ALLOY

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

Conventionally, as a method of forming a UBM or a bump on a silicon wafer, there has been known a method of forming a zinc film by performing a zinc substitution treatment on an aluminum thin film electrode patterned on a wafer and then forming bumps by electroless nickel plating, A bump is formed by electroless nickel plating after the palladium treatment is performed in place of the zinc substitution treatment, or a bump is formed by electroless nickel plating by autocatalytic electroless nickel plating after the surface of the aluminum thin film electrode is directly replaced with nickel And the like are used.

In addition, the UBM or the bump formed with the electroless nickel plated film by this method may be further subjected to electroless copper plating on the electroless nickel plated film in order to improve the electric characteristics, particularly the electric resistance . In this case, since the electroless nickel film has no catalytic property and electroless copper plating can not be directly applied to 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 treatment tends to erode the electroless nickel film and as a result, the substrate (aluminum or aluminum alloy) is attacked (eroded), and the adhesion of the electroless copper plating film formed by the copper substitution treatment is lowered There was a problem.

SUMMARY OF THE INVENTION [

The present invention has been made in view of the above circumstances and has an object of providing an electroless nickel plating film on an aluminum or aluminum alloy and forming an electroless copper plating film on the electroless nickel plating film, A surface treatment of aluminum or an aluminum alloy capable of providing an electroless copper plating film with high adhesiveness by giving an excellent catalytic property without unduly attacking the electroless nickel plating film at the time of treatment, And a method thereof.

The present inventors have made intensive investigations to achieve the above object and found that an electroless nickel plated film is formed on aluminum or an aluminum alloy and an electroless plated copper film is formed on the electroless nickel plated film to form an aluminum or aluminum alloy 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 by displacement plating or electroless plating to form an electroless copper plating film It has been found that an electroless copper plating film can be formed by imparting good catalytic properties and that the resulting electroless copper plating film also has high adhesion.

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

(One):

An aluminum or aluminum alloy which forms an electroless nickel plating film on the aluminum or aluminum alloy of the object to be processed having at least a surface of aluminum or an aluminum alloy and forms an electroless copper plating film on the electroless nickel plating film As a surface treatment method,

A nickel plating step of removing an aluminum oxide film formed on the aluminum or aluminum alloy surface layer of the object to be processed 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 an alloy thereof on the surface of the electroless nickel plating film by displacement plating or electroless plating, and

A copper plating step of forming an electroless copper plating film on the surface of the intermediate plating film

Wherein the surface of the aluminum or aluminum alloy is treated with a surface treatment agent.

(2):

The nickel plating process is performed by immersing the object to be treated in a removing solution for an aluminum oxide film containing a metal substitutable for aluminum to form a replacement metal layer of a replaceable metal with aluminum contained in the removing solution while removing the aluminum oxide film The process,

A step of removing the substituted metal layer with an acidic liquid having an oxidation action, and

A step of forming an electroless nickel plating film on the exposed aluminum or aluminum alloy by removing the replacement metal layer

(1). ≪ / RTI >

(3):

The surface treatment method according to (2), wherein the aluminum oxide film removing liquid comprises a salt of a metal capable of substituting aluminum and an acid.

(4):

The surface (2) according to (2), wherein the aluminum oxide film removing liquid contains a salt or an oxide of a metal capable of substitution with aluminum, a solubilizing agent for the metal ion, and an alkali and has a pH of 10 to 13.5 Processing method.

(5):

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

According to the present invention, when an electroless nickel plated film is formed on aluminum or an aluminum alloy, and an electroless copper plated film is formed on the electroless nickel plated film to treat the surface of aluminum or an aluminum alloy, It is possible to form an electroless copper plating film, and the resultant electroless copper plating film has high adhesion.

DETAILED DESCRIPTION OF THE INVENTION [

Hereinafter, the present invention will be described in more detail.

The surface treatment method of the present invention is a surface treatment method for forming an electroless nickel plating film on an aluminum or aluminum alloy of an object to be processed having at least a surface of aluminum or an aluminum alloy and further forming an electroless copper plating film on the electroless nickel plating film In the surface treatment method of aluminum or aluminum alloy to be formed,

A nickel plating step of removing an aluminum oxide film formed on the aluminum or aluminum alloy surface layer of the object to be processed 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 an alloy thereof on the surface of the electroless nickel plating film by displacement plating or electroless plating, and

A copper plating step of forming an electroless copper plating film on the surface of the intermediate plating film

. Hereinafter, each step will be described.

[Nickel plating process]

In the present invention, an aluminum oxide film formed on a surface layer of aluminum or aluminum alloy to be processed is removed and an electroless nickel plating film is formed on aluminum or aluminum alloy. To remove the aluminum oxide film, a conventionally known method And an aluminum oxide film is removed to form an electroless nickel plating film on the exposed aluminum or aluminum alloy.

In this case, the object to be treated is immersed in a removing liquid for an aluminum oxide film containing a metal capable of substitution with aluminum to form a replacement metal layer of a metal substitutable with aluminum contained in the removing liquid while removing the aluminum oxide film, It is also possible to remove the substitution metal layer with an acidic liquid having an oxidizing action and form an electroless nickel plating film on the exposed aluminum or aluminum alloy.

As the removing solution for aluminum oxide film, a solution containing a salt of a metal capable of substitution with aluminum, an acid, preferably a surfactant (acidic removing solution), or a salt or oxide of a metal substitutable with aluminum, Of a solubilizing agent, an alkali, preferably a surfactant, and having a pH of 10 to 13.5 (an alkaline removing solution) can be suitably used.

(Acidic solution)

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. However, it is preferably a metal having a lower ionization tendency than aluminum. Examples thereof include zinc, iron, cobalt, nickel, , Mercury, silver, platinum, gold, and palladium. Examples of the metal salt include water-soluble salts such as nitrates and sulfates of these metals. Particularly, sulfate is preferable because of the stability of the removal liquid and less aggressiveness against aluminum or aluminum alloy materials. These may be used singly or in combination of two or more. Among them, silver, nickel and copper are less likely to be deposited on other regions, and copper and silver have a significantly lower ionization tendency than aluminum. Therefore, the substitution reaction is more likely to proceed and the etching process time can be shortened Suitable.

The concentration of the metal salt used in the acid-removing liquid is not particularly limited, but it is usually 1 ppm or more, preferably 10 ppm or more, and usually 10,000 ppm or less, preferably 5,000 ppm or less, as the metal amount. If the concentration of the metal salt is too small, it may be necessary to substitute the aluminum with the base aluminum or to replenish the metal salt. On the other hand, when the concentration is excessively large, when the aluminum or the aluminum alloy is an electrode patterned on the wafer, the member other than the aluminum or the aluminum alloy is infiltrated, or the aluminum or the aluminum alloy comes out of the member other than the aluminum or aluminum alloy And there is a case where precipitation occurs.

The acid to be contained in the acidic removing solution is not particularly limited, but it is required to be an acid which dissolves the oxide film, and examples thereof include sulfuric acid, phosphoric acid, hydrochloric acid and hydrofluoric acid. These acids may be used singly or in combination of two or more kinds. Or may be used in combination. Of these, sulfuric acid is preferable from the viewpoints of stability of the liquid to be removed and aggressiveness against aluminum or aluminum alloy materials.

The concentration of the acid in the removal liquid is not particularly limited, 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. If the concentration of the acid is too small, the oxide film may not melt and the effect may not be obtained. On the other hand, if the concentration is too large, the aluminum or aluminum alloy may be impregnated into the member other than the substrate.

(Alkaline removing liquid)

As the metal constituting the metal salt or metal oxide contained in the alkaline removing solution, there is no particular limitation as long as it is a metal that can be replaced with aluminum. However, it is preferably a metal having a lower ionization tendency than aluminum. Examples thereof include manganese, zinc, iron, cobalt, Tin, lead, copper, mercury, silver, platinum, gold, and palladium. Examples of the metal salt include water-soluble salts such as nitrates and sulfates of these metals. Among them, manganese and zinc are preferable because a reduction potential difference with aluminum, which is a base, is small.

The concentration of the metal salt or metal oxide to be used in the alkaline removing solution is not particularly limited, but it is usually at least 1 ppm (mg / L), preferably at least 10 ppm (mg / L) ) Or less, preferably 5,000 ppm (mg / L) or less. If the concentration of the metal salt or the metal oxide is too small, it may be necessary to replenish the metal or metal oxide in a case where it is not sufficiently substituted with the underlying aluminum. On the other hand, when the concentration is excessively large, when the aluminum or the aluminum alloy is an electrode patterned on the wafer, the member other than the aluminum or the aluminum alloy is infiltrated, or the aluminum or the aluminum alloy comes out of the member other than the aluminum or aluminum alloy And there is a case where precipitation occurs.

The solubilizing agent of the metal ion contained in the alkaline removing solution is not particularly limited, but ordinary chelating agents and chelating agents can be used. Specific examples include hydroxycarboxylic acids and salts thereof such as glycolic acid, lactic acid, malic acid, tartaric acid, citric acid, gluconic acid, and heptogluconic acid, glycine, amino dicarboxylic acid, nitrilotriacetic acid, EDTA, Aminocarboxylic acids and salts thereof such as hydroxyethylenediamine triacetic acid, diethylenetriaminepentaacetic acid, and polyaminopolycarboxylic acid; amine-based cheating agents such as HEDP, aminotrimethylphosphonic acid and ethylenediaminetetramethylphosphonic acid; Salts thereof, amine chelating agents such as ethylenediamine, diethylenetriamine, triethylenetetramine and the like can be used.

The concentration of the solubilizing agent used in the alkaline removing solution is not particularly limited, but the total concentration of the solubilizing agent with respect to the metal salt to be used is preferably 0.5 to 10 (molar ratio), preferably 0.8 to 5 (molar ratio).

The alkali to be contained in the alkaline removing solution is not particularly limited, but it is required to be an alkali (base) which dissolves the oxide film. For example, alkaline metals such as LiOH, NaOH and KOH or trimethylammonium hydroxide (TMAH) And hydroxides of quaternary ammonium can be used. The amount of alkali to be added is an amount to bring the pH of the removed liquid into a prescribed range, that is, the pH is 10 to 13.5, preferably 11 to 13. If the pH is less than 10, the dissolution rate may significantly decrease. If the pH is more than 13.5, the dissolution rate may become too fast to be controlled.

It is preferable that the surfactant is included in the removal liquid for oxidation film in terms of imparting wettability to both the acidic removal liquid and the alkaline removal liquid. The surfactant to be used is not particularly limited, and examples thereof include nonionic surfactants such as polyethylene glycol, polyoxyethylene-oxypropylene block copolymer type surfactant, and anionic and cationic surfactants in addition to the surfactants , And from the viewpoint of uniformity, nonionic and anionic types are preferable. These may be used singly or in combination of two or more.

For example, when polyethylene glycol is used as the surfactant, the molecular weight 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 as an upper limit. If the molecular weight is too large, the solubility may deteriorate. On the other hand, if the molecular weight is too small, wettability may not be imparted. As the polyethylene glycol, commercially available products can be used.

(Mg / L), preferably 10 ppm (mg / L) or higher as an upper limit and usually 5,000 ppm (mg / L) or lower as an upper limit, 2,000 ppm (mg / L) or less. If the concentration of the surfactant in the remover is excessively small, the effect of wettability obtained by adding the surfactant may be low. On the other hand, if the concentration is excessively large, the replacement metal is precipitated on a member other than aluminum or aluminum alloy .

It is preferable that the acidic removing solution and the alkaline removing solution are prepared in the form of an aqueous solution from the viewpoint of operational safety. However, it is preferable to use other solvents such as methanol, ethanol, IPA, It is also possible to use a solvent. These solvents may be used singly or in combination of two or more.

The immersing condition in immersing the object to be treated having aluminum or an aluminum alloy in the removing liquid is not particularly limited and may be set appropriately in consideration of the thickness of the aluminum oxide film to be removed and the like. 2 minutes or more, and usually not more than 20 minutes, preferably not more than 15 minutes, as an upper limit. On the other hand, if the immersion time is too long, the removal liquid may invade from the small holes of the replacement metal layer and the aluminum or aluminum alloy may be eluted. If the immersion time is excessively short, the removal of the oxide film may become insufficient. There is a concern.

The temperature for 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 as an upper limit. If the immersion temperature is too low, the oxide film may not be dissolved. On the other hand, if the immersion temperature is excessively high, members other than aluminum or an aluminum alloy may be invaded. In addition, when immersing, it is preferable to perform liquid agitation and rocking of the object to be treated from the viewpoint of uniform treatment.

In the case of using the above-mentioned removing liquid for the oxide film, the aluminum oxide film is removed, and a replacement metal layer of a metal substitutable with aluminum is formed. This replacement metal layer can be removed by an acidic liquid having an oxidizing action, Alternatively, the plating may be performed directly on the aluminum alloy or after the zinc substitution treatment or the palladium treatment.

When removing the substitution metal layer with an acidic liquid having an oxidizing action, an acidic liquid having an oxidizing action is used from the viewpoint of alleviating the reactivity with the underlying aluminum or aluminum alloy. In this case, as the acidic solution having an oxidizing action, an acid having an oxidizing action such as nitric acid or an aqueous solution thereof, an acid having no oxidizing action such as sulfuric acid, hydrochloric acid or the like or an aqueous solution thereof may contain an oxidizing agent such as hydrogen peroxide, sodium persulfate, Ammonium sulfate, potassium persulfate, and the like are preferably used. In this case, the acid has a function of dissolving the substituted metal, and the oxidizing agent has an action of alleviating the reactivity to the aluminum or aluminum alloy substrate. Hydrogen peroxide is preferable in that it is composed of hydrogen and oxygen in the oxidizing agent and becomes water when it is reduced, and sodium persulfate and potassium persulfate are preferable in view of stability and ease of handling.

Here, when nitric acid is used as the acid (and oxidizing agent), 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 / Is not more than 700 ml / L. If the amount of nitric acid is too small, the oxidizing power is low and the reaction may not be stopped. Also, the case where the total amount of nitric acid is 1,000 ml / L is nitric acid.

When the oxidizing agent is used, the amount of the oxidizing agent in the solution 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. If the amount of the oxidizing agent is too small, the oxidizing power is low and the reaction does not stop. On the other hand, if the amount is too large, the economical efficiency may be poor. The concentration of the acid such as hydrochloric acid or sulfuric acid used together with the oxidizing agent is usually 10 g / L or more, preferably 15 g / L or more, and the upper limit is usually 500 g / L or less, preferably 300 g / L or less. If the concentration of the acid is too small, the substitution metal layer may be difficult to dissolve. On the other hand, if the concentration is too large, there is a risk of erosion of members other than aluminum or aluminum alloy. The acid used herein is preferably non-oxidizing, but may be an oxidizing acid such as nitric acid, or an oxidizing acid may be mixed with a non-oxidizing acid.

In the dissolution treatment, the treatment time is not particularly limited. For example, the dissolution treatment may be performed for 5 to 300 seconds, and the dissolution treatment temperature may be, for example, 10 to 40 占 폚. During the dissolving treatment, the object to be plated may be oscillated even when stopped, and liquid stirring may be performed.

An aluminum oxide film is removed to form an electroless nickel plating film on the exposed aluminum or aluminum alloy. A known electroless nickel plating bath can be used for the electroless nickel plating, and examples thereof include electroless nickel plating baths containing nickel sulfate, organic acid (succinic acid, malic acid, citric acid, etc.) and sodium hypophosphite And a commercially available plating bath may be used.

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

Further, electroless nickel plating can be carried out directly on the surface of aluminum or aluminum alloy, and after the activation treatment to the surface of aluminum or aluminum alloy is carried out by zinc substitution treatment, palladium treatment or the like and then electroless nickel plating treatment is carried out do. As such an activation treatment, it is particularly preferable to form a zinc coating on the surface of aluminum or aluminum alloy by performing a zinc substitution treatment, in particular an alkaline zinc substitution treatment, from the viewpoint of improving the adhesion of the plating coating.

Here, as the zinc substitution treatment, specifically, treatment with substitutional precipitation of zinc is carried out by using a solution containing a zinc salt. In the case of the alkaline zinc substitution treatment, an alkaline alkaline solution is used. As the acidic zinc substitution treatment, a treatment for substituting zinc by using a solution containing an acidic zinc salt is carried out. As shown in Fig. As the palladium treatment, palladium is substituted by precipitation using a solution containing a palladium salt, and can be carried out by a 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 plated film formed in the nickel plating step by displacement plating or electroless plating. For example, metal (Ag, Au, Pd, Pt, Ph) may be used as the substitutional plating or electroless plating, using a known substitutional plating bath or electroless plating bath containing Ag, Au, Pd, (Ag, Au, Pd, Pt, Ph) salt, a complexing agent (organic acid, EDTA, etc.) containing an organic acid (succinic acid, malic acid, citric acid, etc.) And an electroless plating bath containing a reducing agent (formic acid, sodium hypophosphite, hydrazine, etc.), or a commercially available plating bath may be used.

The plating temperature and the plating time are usually selected in accordance with the film thickness of the plating film to be formed. Usually, the plating temperature is 30 [deg.] C To 80 캜, and the plating time is 10 seconds to 10 minutes. An intermediate plating film of Ag, Au, Pd, Pt, Rh, or an alloy thereof is formed and an electroless copper plating film is formed by a copper plating process to be described later to provide a good catalytic property to form an electroless copper plating film .

[Copper plating process]

In the present invention, an electroless copper plating film is formed on the surface of the intermediate plating film formed in the intermediate plating step. A known electroless copper plating bath can be used for the electroless copper plating, and examples thereof include electroless copper plating baths containing copper sulfate, a complexing agent (tartaric acid, EDTA and the like), formalin, etc., and commercially available plating You can also use a bath.

The thickness of the electroless copper plating film to be formed is usually about 0.05 to 10 占 퐉. The plating temperature and the plating time are selected in accordance with the thickness of the formed plating film. Usually, the plating temperature is 20 to 75 占 폚, Is 5 minutes to 6 hours.

As the object to be processed which has aluminum or an aluminum alloy on at least the surface to which the present invention is applied, a non-aluminum material (for example, silicon, FRA (substrate of a printed substrate) ) May be covered with aluminum or an aluminum alloy in whole or in part. The shape of the aluminum or aluminum alloy is not particularly limited, and can be suitably applied to, for example, a blank material, a rolled material, a cast material, and a coating film. When the 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. Examples of the method for forming the film include vapor deposition, sputtering, ion plating, The plating method is suitable.

The thickness of the coating film is usually not less than 0.5 mu m, preferably not less than 1 mu m, from the viewpoint of reliably retaining the aluminum or aluminum alloy substrate. The upper limit of the thickness is not particularly limited, but is usually 100 占 퐉 or less.

Aluminum or an aluminum alloy is not particularly limited as long as it is an alloy of Al-Si (Si content: 0.5 to 1.0 wt%) and Al-Cu (Cu content: 0.5 to 1.0 wt% It is also applicable to coatings.

(Example)

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example 1]

A silicon plate coated with an aluminum layer having a thickness of 5 탆 was used as a material to be plated by a sputtering method. The aluminum layer was subjected to the treatment shown in Table 1 in order. Table 2 shows the evaluation results of the characteristics of the obtained plating film.

process Chemical solution Condition (One)  Cleaner / Surface cleaning EpiTas MCL-16 ^*  50 ℃ for 5 minutes (2)  Remove oxide film  The following oxide film remover  50 ° C for 1 minute (3)  Remove smut 50% HNO ₃  20 ℃ for 30 seconds (4)  First kinetics treatment EpiTas MCT-17 ^*  20 ℃ for 10 seconds (5)  Remove Ginckite Film 50% HNO ₃  20 ℃ for 60 seconds (6)  Secondary kinetics treatment EpiTas MCT-17 ^*  20 ℃ for 30 seconds (7)  Electroless nickel plating Epithas NPR-18 ^*  Thickness 3 탆 (8)  Substitution gold plating (gold sulfite) EpiTas TDS-20 ^*  Film thickness 0.04 mu m (9)  Electroless copper plating EpiTas PSP-20 ^*  Film thickness 8 탆

*: Manufactured by Uemura Kogyo K.K.

Loss of oxidation film: 2 g / L of zinc sulfate as a metal salt, 10 g / L of EDTA · 2Na as a solubilizing agent, 1 g / L of PEG (polyethylene glycol) -1000 as a surfactant, NaOH as an alkali, Adjusted aqueous solution

[Example 2]

Except that the substitution gold plating (gold sulfite) of (8) was replaced with substitution gold plating (cyan plating) (chemical solution: Epytas TDL-20 (manufactured by Uemura Kogyo K.K. The treatment was carried out in the same manner as in Example 1. Table 2 shows the evaluation results of the characteristics of the obtained plating film.

[Example 3]

Except that the substitution gold plating (gold sulfite) of Example 8 was replaced by electroless Pd plating (chemical solution: EpiTas TFP-30 (manufactured by Uemura Kogyo K.K.), condition: thickness 0.06 탆) The treatment was carried out in the same manner. Table 2 shows the evaluation results of the characteristics of the obtained plating film.

[Comparative Example 1]

The treatment was carried out in the same manner as in Example 1 except that the substitution gold plating (gold sulfite) of (8) was not carried out. Table 2 shows the evaluation results of the characteristics of the obtained plating film.

[Comparative Example 2]

Except that the substitution gold plating (gold sulfite) of (8) was changed to copper substitution treatment (chemical solution: copper sulfate 0.5 g / L sulfuric acid (62.5%) 10 g / L) The treatment was carried out in the same manner. Table 2 shows the evaluation results of the characteristics of the obtained plating film.

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

Appearance of electroless copper plating film: Observation was made by naked eyes and a stereoscopic microscope, and it was judged that there was no unattached and unevenness, and that there was no unattached or stained.

Adhesion: The silicon plate was bent and broken with the plated film, and the plated film was broken without being peeled off.

· Attack on the possession: It was decided that there was no attack (erosion) against aluminum substrate, and there was "no".

Claims (7)

An aluminum or aluminum alloy which forms an electroless nickel plating film on the aluminum or aluminum alloy of the object to be processed having at least a surface of aluminum or an aluminum alloy and forms an electroless copper plating film on the electroless nickel plating film As a surface treatment method, The object to be treated is immersed in a removing solution for an aluminum oxide film containing a metal capable of substitution with aluminum to remove the aluminum oxide film formed on the aluminum or aluminum alloy surface layer of the object to be processed, A step of forming a substitution metal layer of a possible metal, A step of removing the substituted metal layer with an acidic liquid having an oxidation action, and A nickel plating step comprising a step of forming an electroless nickel plating film on the aluminum or aluminum alloy from which the replacement metal layer is removed and exposed, An intermediate plating step of forming an intermediate plating film of Ag, Au, Pd, Pt, Rh or an alloy thereof on the surface of the electroless nickel plating film by displacement plating or electroless plating, and A copper plating step of forming an electroless copper plating film on the surface of the intermediate plating film Wherein the surface of the aluminum or aluminum alloy is treated with a surface treatment agent. The surface treatment method according to claim 1, wherein the aluminum oxide film removing liquid contains a salt of a metal capable of substituting aluminum and an acid. The aluminum oxide film-forming composition according to claim 1, wherein the aluminum oxide film-removing liquid contains a salt or oxide of a metal capable of substitution with aluminum, a solubilizing agent for the metal ion, and an alkali and has a pH of 10 to 13.5 Surface treatment method. The surface treatment method according to claim 2 or 3, wherein the aluminum oxide film removing liquid further contains a surfactant. The surface treatment method according to claim 2, wherein the aluminum and the replaceable metal are zinc, iron, cobalt, nickel, tin, lead, copper, mercury, silver, platinum, gold or palladium. The surface treatment method according to claim 3, wherein the aluminum and the substitutable metal are manganese, zinc, iron, cobalt, nickel, tin, lead, copper, mercury, silver, platinum, gold or palladium. The surface treatment method according to claim 1, wherein the electroless nickel plating film is formed on the exposed aluminum or aluminum alloy after the replacement metal layer is removed, either directly or after zinc substitution treatment.