JP2009132959A - Aluminum removal treatment method, and aluminum removal treatment liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum or aluminum alloy melting removal treatment method where, when aluminum or aluminum alloy members with almost same oxide films having almost the same oxide films are subjected to dissolving treatment, the effective treatment area per the unit quantity of the treatment liquid is remarkably improved. <P>SOLUTION: A method for removing only an aluminum or aluminum alloy part in each aluminum or aluminum alloy member having an oxide film whereon, using a treatment liquid at least comprises: (1) an element simple substance having an ionization tendency lower than that of aluminum or a compound having the same element; and (2) acid capable of forming an oxidized compound with the compound in the (1), only the aluminum or aluminum alloy part is removed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a treatment method for removing aluminum from an aluminum or aluminum alloy member having an oxide film, and a treatment liquid therefor.

  In the technical fields of metal and semiconductor thin films, thin wires, dots, etc., the phenomenon of electrical, optical and chemical peculiarities can be seen by confining the movement of free electrons in a size smaller than a certain characteristic length. It has been known. Such a phenomenon is called “quantum mechanical size effect (quantum size effect)”. Research and development of functional materials applying such a unique phenomenon is being actively conducted. Specifically, a material having a structure finer than several hundred nm is referred to as a “microstructure” or “nanostructure”, and is one of the objects of material development.

  As a method for manufacturing such a fine structure, for example, a method for directly manufacturing a nano structure by a semiconductor processing technique including a fine pattern forming technique such as photolithography, electron beam exposure, and X-ray exposure can be given.

In particular, research on a method for producing a nanostructure having a fine structure using an anodic oxide film of aluminum has attracted attention and has been conducted a lot.
For example, as a method for forming a regular structure in a self-regulating manner, an aluminum oxide film (anodized film) obtained by subjecting aluminum to an anodizing treatment in an electrolytic solution can be mentioned. It is known that a plurality of fine pores (micropores) having a diameter of about several nm to several hundred nm are regularly formed in the anodized film. By using this self-ordering of the anodized film and obtaining a perfectly regular arrangement, theoretically, hexagonal prism cells with a regular hexagonal bottom centered around the micropores are formed, and adjacent micropores are formed. It is known that the connecting line forms an equilateral triangle.
For example, Non-Patent Document 1 describes an anodized film in which the pore diameter variation of micropores is 3% or less. Non-Patent Document 2 describes that pores are spontaneously formed in the anodized film as the oxidation proceeds. Non-Patent Document 3 also proposes forming an Au dot array on a Si substrate using a porous oxide film as a mask.

  The greatest feature as a material of the aluminum anodic oxide film is that a plurality of micropores adopt a honeycomb structure in which a plurality of micropores are formed in a direction substantially perpendicular to the substrate surface and in parallel at substantially equal intervals. In addition to this, the pore diameter, the pore interval, and the pore depth can be controlled relatively freely, which is a feature not found in other materials (see Non-Patent Document 3).

  As an application example of the anodic oxide film, various devices such as a nano device, a precision filter device, a magnetic device, and a light emitter are known.

  Such an anodic oxide film device has many fields where performance such as high temperature durability, acid resistance / alkali resistance, etc. is required for use. On the other hand, in a device in which aluminum remains, heat deformation peculiar to aluminum or acid / Although the deterioration of the device itself due to the corrosiveness due to alkali, for example, the method described in Non-Patent Document 4 etc. can be used in a state in which aluminum is dissolved and removed by chemical dissolution treatment to form a device having only an anodized film. It is thriving. However, the removal of aluminum by such chemical treatment has a large variation in liquid properties due to processing fatigue, and the effective treatment area per unit amount of the treatment liquid is not sufficient, and improvement is desired.

JP 2000-31462 A H. Masuda et. Al. , Jpn. J. et al. Appl. Phys. , Vol. 37 (1998), pp. L1340-1342, Part 2, No. 1 11A, 1 November 1998 (FIG. 2.) “Surface Technology Handbook”, edited by Surface Technology Association (1998), Nikkan Kogyo Shimbun, p. 490-553 Hideki Masuda, “Highly Ordered Metal Nanohole Array Based on Anodized Alumina”, Solid State Physics, 1996, Vol. 31, No. 5, p. 493-499 Journal of Aluminum Research No. 4, Tohoku University Itaya

  Accordingly, an object of the present invention is to provide an aluminum dissolution and removal method and a treatment liquid that are excellent in effective treatment area per unit amount of treatment liquid.

  As a result of intensive studies to achieve the above object, the present inventors have found that in the treatment liquid, a compound having an element that has a higher ionization tendency than aluminum and an acid capable of forming an oxide compound with the compound are contained in the treatment liquid. It is found that the effective treatment area per unit amount of the treatment liquid is greatly improved by adding to the composition, and further, the effect of increasing the treatment speed is found by adding a compound having an effect of corroding aluminum. Completed the invention.

That is, the present invention provides the following (i) to (iv).
(I) A method of removing only the aluminum or aluminum alloy part of the aluminum or aluminum alloy member having an oxide film, comprising at least:
(1) an elemental element having a lower ionization tendency than aluminum, or a compound having the element, and (2) an acid capable of forming an oxide compound with the compound of (1) above,
A treatment method comprising removing only aluminum or an aluminum alloy part using a treatment solution containing
(Ii) The element of (1) is at least one element selected from copper, mercury, silver, palladium, platinum and gold, and the acid of (2) is nitric acid, Processing method.
(Iii) In the processing solution,
(3) an elemental element having an action of corroding aluminum, and a compound having the element,
The processing method according to (i) or (ii) above, comprising:
(Iv) The treatment method according to any one of (i) to (iii) above, wherein the compound of (3) is hydrochloric acid or a chloride compound.
(V) The processing method according to any one of (i) to (iv), wherein the aluminum or aluminum alloy member having the oxide film is obtained by anodizing the surface of an aluminum plate.
(Vi) A treatment liquid used for the treatment according to any one of (i) to (v) above.

  According to the present invention, the amount of aluminum dissolved per treatment liquid (dissolution weight) is high, and when the same or substantially the same size aluminum having the same oxide film or an alloy member thereof is dissolved, Thus, an aluminum or aluminum alloy dissolution / removal treatment solution can be obtained that greatly improves the effective treatment area, and is particularly useful for the purpose of dissolving only the aluminum portion of an aluminum member having an oxide film.

  The present invention is described in detail below.

The aluminum dissolution removal treatment liquid according to the present invention is at least:
(1) A simple element having a lower ionization tendency than aluminum, and a compound having the element,
(2) having an acid capable of forming an oxide compound with the compound of (1) above.

<(1) Element simple substance having lower ionization tendency than aluminum and compound having the element>
Specific elements of (1) above include manganese, zinc, chromium, iron, cadmium, cobalt, nickel, tin, lead, hydrogen, antimony, bismuth, copper, mercury, silver, palladium, platinum, gold, etc. Can be mentioned. Since the dissolution of aluminum dissolves due to the ionization tendency of aluminum and the precipitation of the above elements due to the difference in ionization tendency with these elements, it is preferable that the difference in ionization tendency with aluminum is larger, such as copper, mercury, Silver, palladium, platinum and gold are preferable, and copper is particularly preferable from the viewpoint of safety and price.

  Although it does not specifically limit as a compound of the element mentioned above, A halide, an oxide, a hydroxide, etc. are preferable from a viewpoint easy to exist as an ion in the aqueous solution before a process.

  As these preferable addition concentrations of the element simple substance having a lower ionization tendency than aluminum and the compound having the element, 0.01 to 50% by mass is preferable, 0.05 to 40% by mass is more preferable, and 0.1 to 30% by mass is particularly preferred. Below these ranges, the solubility of aluminum is inferior. Above these ranges, the action of dissolving the oxide film works, which is not preferable.

<(2) Acid capable of forming an oxidized compound with the compound of (1)>
Examples of the acid (2) include inorganic acids such as nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid and arsenic acid, and oxalic acid, malonic acid, succinic acid, acetic acid, butyric acid, formic acid, benzoic acid, maleic acid and the like. Any of the organic acids including carboxylic acid can be used, but nitric acid and sulfuric acid are particularly preferable in view of copper, which is a particularly preferable element of (1).

  The preferred concentration of the acid capable of forming an oxide compound with the compound (1) is preferably 0.01 to 30% by mass, more preferably 0.05 to 25% by mass, and 0.1 to 20%. Mass% is particularly preferred. Below these ranges, the solubility of aluminum is inferior. Above these ranges, the action of dissolving the oxide film works, which is not preferable.

<Other additives>
In the present invention, various materials other than the compounds (1) and (2) described above can be contained in the treatment liquid.
For example, in order to further dissolve only the aluminum member that is the main object of the present invention, it is preferable to add a compound that corrodes aluminum, and it is preferable to add a chloride. More specifically, hydrochloric acid, sodium chloride, calcium chloride, magnesium chloride, and potassium chloride are preferable, and hydrochloric acid and sodium chloride are particularly preferable.
As addition amount, 1-30 mass% is preferable, and 5-20 mass% is still more preferable. Below these ranges, the solubility of aluminum is inferior. Above these ranges, the action of dissolving the oxide film works, which is not preferable.
In addition, chloride is presumed to have an effect of suppressing dissolution of an oxide film that is not desired to be dissolved, and is preferable from this viewpoint.

  0-60 degreeC is preferable, as for the process liquid temperature which added the compound mentioned above, 5-50 degreeC is more preferable, and 10-40 degreeC is especially preferable. Below these ranges, the solubility of aluminum is inferior. Above these ranges, the action of dissolving the oxide film works, which is not preferable.

  The aluminum removal treatment is performed by contacting with the treatment liquid described above. The method of making it contact is not specifically limited, For example, the immersion method and the spray method are mentioned. Of these, the dipping method is preferred. The contact time at this time is preferably 10 seconds to 5 hours, and more preferably 1 minute to 3 hours.

  The dipping method is a treatment in which an aluminum member having an oxide film is dipped in the above-described aluminum dissolution and removal solution. Stirring during the dipping process is preferable because a uniform process is performed.

<Aluminum member that can be dissolved>
The aluminum member is not particularly limited. For example, a pure aluminum plate; an alloy plate containing aluminum as a main component and containing a small amount of foreign elements; a substrate obtained by depositing high-purity aluminum on low-purity aluminum (for example, recycled material); silicon Examples of the substrate include a substrate in which high purity aluminum is coated on the surface of a wafer, quartz, glass or the like by a method such as vapor deposition or sputtering; a resin substrate in which aluminum is laminated.

In the present invention, the thickness of the aluminum substrate is preferably 0.05 mm to 1 mm, more preferably 0.1 mm to 0.8 mm, and further preferably 0.2 to 0.5 mm. preferable.
When the thickness of the aluminum substrate is in the above range, the treatment method of the present invention can easily remove the aluminum or aluminum alloy part without substantially dissolving the oxide film. When the thickness of the aluminum substrate is in the above range, the member having an oxide film from which the aluminum or aluminum alloy portion obtained by the processing method of the invention has been removed can be various devices such as nanodevices, precision filter devices, magnetic devices, light emitters, etc. It can be used for devices.

  The surface of the aluminum substrate is preferably subjected to degreasing and mirror finishing in advance.

<Degreasing treatment>
Degreasing treatment uses acids, alkalis, organic solvents, etc. to dissolve and remove organic components such as dust, fat, and resin that adhere to the aluminum surface, and causes defects in each treatment described later due to the organic components. This is done for the purpose of preventing the occurrence of.
A conventionally known degreasing agent can be used for the degreasing treatment. Specifically, for example, various commercially available degreasing agents can be used by a predetermined method.

Especially, the following each method is illustrated suitably.
A method in which an organic solvent such as alcohol (for example, methanol), ketone, benzine, volatile oil or the like is brought into contact with the aluminum surface at room temperature (organic solvent method); a solution containing a surfactant such as soap or neutral detergent at a temperature from 80 to 80 A method in which the aluminum surface is contacted at a temperature up to ℃, and then washed with water (surfactant method); a sulfuric acid aqueous solution having a concentration of 10 to 200 g / L is brought into contact with the aluminum surface at a temperature from room temperature to 70 ° C for 30 to 80 seconds. Then, a method of washing with water; while a sodium hydroxide aqueous solution having a concentration of 5 to 20 g / L was brought into contact with the aluminum surface at room temperature for about 30 seconds, a direct current having a current density of 1 to 10 A / dm ² was passed with the aluminum surface as a cathode. And then neutralizing by contacting with a nitric acid aqueous solution having a concentration of 100 to 500 g / L; various known electrolytic solutions for anodizing treatment are usually used. In while in contact with the aluminum surface, the aluminum surface by applying a direct current of a current density of 1 to 10 A / dm ² in the cathode, or a method of electrolysis by passing an alternating current; the alkaline aqueous solution in the concentration of 10 to 200 g / L A method of bringing the aluminum surface into contact at 40 to 50 ° C. for 15 to 60 seconds, and then neutralizing by contacting with an aqueous nitric acid solution having a concentration of 100 to 500 g / L; a surfactant, water or the like was mixed with light oil or kerosene. A method in which the emulsion is brought into contact with the aluminum surface at a temperature from room temperature to 50 ° C. and then washed with water (emulsion degreasing method); a mixed solution of sodium carbonate, phosphates, surfactants, etc. is brought to a temperature from room temperature to 50 ° C. There is a method of contacting with the aluminum surface for 30 to 180 seconds and then washing with water (phosphate method).

  The degreasing treatment is preferably a method in which the fat content on the aluminum surface can be removed while aluminum dissolution hardly occurs. In this respect, the organic solvent method, the surfactant method, the emulsion degreasing method, and the phosphate method are preferable.

<Mirror finish processing>
The mirror finishing process is performed to eliminate unevenness on the surface of the aluminum substrate and improve the uniformity and reproducibility of the particle forming process by an electrodeposition method or the like. Examples of the irregularities on the surface of the aluminum substrate include rolling stripes generated during rolling in the case where the aluminum substrate is manufactured through rolling.
In the present invention, the mirror finish is not particularly limited, and a conventionally known method can be used. Examples thereof include mechanical polishing, chemical polishing, and electrolytic polishing.

  Examples of the mechanical polishing include a method of polishing with various commercially available polishing cloths, and a method of combining various commercially available abrasives (for example, diamond, alumina) and a buff. Specifically, a method in which the method using an abrasive is performed by changing the abrasive used from coarse particles to fine particles over time is preferably exemplified. In this case, the final polishing agent is preferably # 1500. Thereby, the glossiness can be 50% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 50% or more).

As chemical polishing, for example, “Aluminum Handbook”, 6th edition, edited by Japan Aluminum Association, 2001, p. Various methods described in 164 to 165 may be mentioned.
Further, phosphoric acid - nitric acid method, Alupol I method, Alupol V method, Alcoa R5 _{method, H 3 PO 4 -CH 3 COOH} -Cu _{method, H 3 PO 4 -HNO 3 -CH} 3 COOH method are preferable. Among these, the phosphoric acid-nitric acid method, the H ₃ PO ₄ —CH ₃ COOH—Cu method, and the H ₃ PO ₄ —HNO ₃ —CH ₃ COOH method are preferable.
By chemical polishing, the glossiness can be made 70% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 70% or more).

As electrolytic polishing, for example, “Aluminum Handbook”, 6th edition, edited by Japan Aluminum Association, 2001, p. Various methods described in 164 to 165 may be mentioned.
Moreover, the method described in US Pat. No. 2,708,655 is preferable.
“Practical Surface Technology”, vol. 33, no. 3, 1986, p. The method described in 32-38 is also preferably exemplified.
By electropolishing, the gloss can be 70% or more (in the case of rolled aluminum, both the rolling direction and the width direction are 70% or more).

  These methods can be used in appropriate combination. For example, a method of using an abrasive is preferably performed by changing the abrasive to be used from coarse particles to fine particles over time, and then performing electrolytic polishing.

By mirror finishing, for example, a surface having an average surface roughness _Ra of 0.1 μm or less and a glossiness of 50% or more can be obtained. The average surface roughness _Ra is preferably 0.03 μm or less, and more preferably 0.02 μm or less. Further, the glossiness is preferably 70% or more, and more preferably 80% or more.
The glossiness is a regular reflectance obtained in accordance with JIS Z8741-1997 “Method 3 60 ° Specular Gloss” in the direction perpendicular to the rolling direction. Specifically, using a variable angle gloss meter (for example, VG-1D, manufactured by Nippon Denshoku Industries Co., Ltd.), when the regular reflectance is 70% or less, the incident reflection angle is 60 degrees and the regular reflectance is 70%. In the case of exceeding, the incident / reflection angle is 20 degrees.

<Oxide film formation treatment by anodization>

  In the case of forming an oxide film of aluminum or an aluminum alloy member by anodic oxidation, for example, a method of using an aluminum substrate as an anode in a solution having an acid concentration of 0.01 to 5 mol / L is used. it can. The solution used for the anodizing treatment is preferably an acid solution, more preferably sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid, etc., among which sulfuric acid, phosphoric acid, Oxalic acid is particularly preferred. These acids can be used alone or in combination of two or more.

The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be determined in general. In general, however, the electrolyte concentration is 0.01 to 5 mol / L, the solution temperature is -10 to 30 ° C., and the current density. 0.01 to 20 A / dm ² , voltage 3 to 300 V, electrolysis time 0.5 to 30 hours are preferable, electrolyte concentration 0.05 to 3 mol / L, solution temperature −5 to 25 ° C., current density 0 0.05 to 15 A / dm ² , voltage 5 to 250 V, electrolysis time 1 to 25 hours is more preferable, electrolyte concentration 0.1 to 1 mol / L, solution temperature 0 to 20 ° C., current density 0.1 to More preferably, it is 10 A / dm ² , a voltage of 10 to 200 V, and an electrolysis time of 2 to 20 hours.

The thickness of the anodized film is preferably 1 to 2000 μm, more preferably 10 to 1500 μm, and still more preferably 100 to 1000 μm.
The pore diameter of the micropore is preferably 0.01 to 0.5 μm.
The average pore density is preferably from 50 to 1,500 / [mu] m ^2.

  The area ratio occupied by the micropores is preferably 20 to 50%. The area ratio occupied by the micropores is defined by the ratio of the total area of the micropore openings to the area of the aluminum surface.

The aluminum or aluminum alloy member having an oxide film may be a substrate having a surface expansion ratio measured by the BET method of 1.2 or more, more preferably a substrate having a surface area of 1.2 to 120. More preferably, the substrate is 5 to 55.
In general, a member having a large surface area is more easily dissolved because it has a large contact area with the treatment liquid when immersed in the treatment liquid. However, even if the area expansion ratio is in the above range, if the method of the present invention is used, it is possible to dissolve and remove only aluminum or an aluminum alloy while leaving an oxide film. For this reason, the oxide film obtained after dissolving and removing aluminum or the like can be provided as a fine structure that can be further enhanced in function as a functional material.
Here, the surface expansion rate is an index representing the degree of anodization with respect to the specular plate, the unit being dimensionless. When measuring with a sample size of the same geometric area, the surface area expansion ratio is determined by the BET surface area (BET surface area [m] of the aluminum substrate after the anodizing treatment and the smooth aluminum substrate without the anodizing treatment. ² ]) ratio (processed substrate / smooth substrate). When the sample sizes are different, the geometric area corresponding to the sample size is corrected. That is, the area expansion ratio is a ratio of the value obtained by dividing the BET surface area of the aluminum substrate after the anodizing treatment and the smooth aluminum substrate not subjected to the anodizing treatment by the geometric area (treated substrate / smooth substrate). ) Here, the geometric area is an area calculated from a size obtained by measuring an area assumed to be a two-dimensional plane with calipers or the like.
Further, the smooth aluminum substrate not subjected to anodic oxidation treatment, defined surface roughness R _a in JIS B0601-1994 exhibits the following aluminum substrate 0.2 [mu] m.

The BET method is a method in which a substance having a known adsorption occupation area is adsorbed on a sample surface at the temperature of liquid nitrogen, and the surface area of the sample is obtained from the amount. In the present invention, the BET method can be performed by a conventional method. For example, the Catalysis Society of Japan, “Catalyst Experiment Handbook”, Kodansha, 1989, p. This can be done with reference to the description of 167-168. The measuring instrument used for BET method is not specifically limited, For example, a commercially available measuring instrument is mentioned. Specifically, for example, Flowsorb manufactured by Shimadzu Corporation and Autosorb manufactured by Cantachrome are listed.
As the adsorbate, organic compounds such as nitrogen, krypton, benzene and toluene are used. Of these, nitrogen and a mixed gas of nitrogen and helium are generally used. If the surface area is relatively low, krypton gas is used.
The aluminum plate whose surface area [m ² ] is measured by the BET method is preferably pretreated. The pretreatment is preferably performed at 200 to 500 ° C. in a vacuum for 1 to 4 hours. A method of heating in an inert flow gas after vacuum storage is also preferably used.
Although the adsorption time in the BET method varies depending on the BET surface area and the sample amount, for example, in the size of 25 mm × 20 mm, it is generally in the range of 30 minutes to 15 hours. The desorption time is approximately 5 to 10 minutes.

  The film thickness of the anodized film after the aluminum dissolution and removal treatment is preferably 1 to 1000 μm, and more preferably 10 to 500 μm.

  The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.

[Examples 1 to 5, Comparative Example 1]
1. Oxidation film formation treatment by anodization A high-purity aluminum substrate (manufactured by Sumitomo Light Metal Co., Ltd., purity 99.99 mass%, thickness 0.4 mm) was cut so that it could be anodized in an area of 10 cm square, 0.30 mol / An aluminum member having an anodized film was formed by anodizing with an electrolyte of L sulfuric acid for 10 hours under conditions of a voltage of 25 V, a liquid temperature of 15 ° C., and a liquid flow rate of 3.0 m / min. The thickness of the oxide film at this time was measured with an eddy current film thickness meter EDY-1000 manufactured by Sanko Electronics. The results are shown in Table 1. The area expansion ratio is the ratio of the BET surface area (BET surface area [m ² ]) between the anodized aluminum substrate and the smooth anodized aluminum substrate (treated substrate / smooth substrate). The area expansion ratio measured in (1) was in the range of 80-110.

2. Aluminum removal treatment The sample obtained above was dipped in 10 L of the treatment liquid shown in Table 1 to visually evaluate whether only the aluminum substrate could be removed. Table 1 shows the number of 10 cm square aluminum substrates that could be removed. Moreover, in order to judge whether melt | dissolution of the oxide film was suppressed, the thickness of the oxide film after an aluminum removal process was measured with the eddy current type film thickness meter EDY-1000 made from Sanko Electronics. The results are shown in Table 1.

3. Separately, an aluminum substrate (manufactured by Sumitomo Light Metal Co., Ltd., purity 99.9% by mass, thickness 0.4 mm) was similarly anodized, and the thickness of the oxide film after aluminum removal treatment was measured under the same conditions. There was no difference.

Claims (5)

A method of removing only the aluminum or aluminum alloy part of an aluminum or aluminum alloy member having an oxide film,
(1) an elemental element having a lower ionization tendency than aluminum, or a compound having the element, and (2) an acid capable of forming an oxide compound with the compound of (1) above,
A treatment method comprising removing only aluminum or an aluminum alloy part using a treatment solution containing   The processing method according to claim 1, wherein the element (1) is at least one element selected from copper, mercury, silver, palladium, platinum, and gold, and the acid (2) is nitric acid. In the above processing solution,
(3) an elemental element having an action of corroding aluminum, and a compound having the element,
The processing method according to claim 1 or 2, characterized by comprising:   The processing method according to claim 1, wherein the compound (3) is hydrochloric acid or a chlorinated compound.   The processing liquid used for the process in any one of the said Claims 1-4.