JP2007126693A - Aluminum material of hardly eluting impurity and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a lightweight aluminum member that is used in a semiconductor device, or a portion or component which hates impurities in the coating film. <P>SOLUTION: The aluminum metal material having the anodized coating film on the surface is characterized in that an amount of ions eluted from the coating film into a solvent of pure water at 60°C for continuous 360 hours is 5 μS/cm or less by a conductivity conversion factor, which is defined in the specification. Such a coating film as to elute little amount of the impurities is obtained by the steps of: cleaning the anodized coating film with an acoustic method and/or an electrolytic method; and sealing it and irradiating it with far infrared rays as post-treatment. The anodized coating film comprises mainly aluminum oxide and/or aluminum hydroxide of 80% or more but less than 100% and the balance being a coating assistance component. The material is suitable for the semiconductor device, or the portion or component which hates the elution of the impurities. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an aluminum material suitable for use in an environment where the elution of impurities in the material affects.

As the mounting density is improved in a semiconductor manufacturing apparatus, the generation of metals and impurities from the material constituting each component becomes a problem. For this reason, stainless steel metal products with little generation of impurities have been mainly used on the inner surface of vacuum devices. However, along with the recent increase in the size of the apparatus, an increase in the weight of the product, the cost of moving the product, etc. are inevitably added, and in order to solve this, weight reduction is an inevitable problem.

Here, aluminum attracts attention as a material that is lightweight, low-cost, and has good workability. However, corrosion resistance is a problem that must be overcome when using aluminum. There is an anodic oxide film processing method as a simple and reliable processing method of corrosion resistance. However, this method requires countermeasures because impurities are mixed in during the process.

The film formed by the anodization treatment is structurally similar to the honeycomb structure, with a microscopic hole in the form of a honeycomb from the material to the surface, a porous layer that hits the hole of the nest and its wall surface, It is a porous film made up of a lid (barrier layer) at the bottom of the hole. When the role of the porous film is roughly divided, the items related to corrosion resistance are the film thickness, the sealing treatment and the composition of the coating, and the generation of impurities from the coating is largely determined by the component of the sealing treatment and the coating composition. .

Here, the sealing treatment is a treatment for solving the problem because the corrosion resistance decreases due to the entry / exit of corrosive substances from the outside if the holes of the porous layer remain anodized. In this method, the anodized film (Al ₂ O ₃ ) is changed to a hydrate (Al (OH) ₃ ) by heat and moisture. This reaction causes volume expansion in the coating, which further reduces the micropores in the porous layer. This is called hydration sealing, and currently the boiling water method and the steam method are used, and the metal salt method, the room temperature method and the like are used as other methods.

The method for measuring the elution of impurities from the film is performed by a method of measuring the elution amount of ions from the film to the solvent by electric conductivity. For example, as described in Patent Document 1, a method for monitoring and removing ions dissolved in cooling water or the like is proposed, and a system that combines units that constantly measure the electrical conductivity of cooling water and remove eluted ions is proposed. However, it is originally most desirable to prevent ions from eluting from the parts used.
JP 2003-36869 A

In the aluminum material according to the present invention, the generation of metal or impurities from the film is considered to be mainly caused by residual components in the porous layer, elution from the wall surface, or elution of metals and metal salts during sealing. The purpose is to reduce it.

The present invention is an aluminum metal material having an anodic oxide film with a small amount of impurity elution on the surface, the amount of impurity elution specified below is 5 μS / cm or less in electrical conductivity, and the corrosion resistance is 10 μm. It is an aluminum material characterized by having a salt spray test of 360 hours and a rating number (RN) of 9.5 or more, and a method for producing the same. The amount of impurities stipulated here is a measurement method utilizing the increase in electrical conductivity in proportion to the amount of leaching into pure water, and the measurement method is metal corrosion as defined in JIS-K2234. Using a property test apparatus, an aluminum material sample having an area of 18 cm ² (both sides of 3 cm × 3 cm) is placed in a glass sealed container containing 500 ml of pure water, heated to 60 ° C., and the evaporated vapor is cooled and refluxed. It is shown with the electrical conductivity measured for the solvent water after 360 hours continuous heating operation in the state.

The solvent used for impurity elution is pure water having a purity of 1 μS / cm or less, and usually distilled water is used. The electrical conductivity is measured with a conductivity meter SC82 manufactured by Yokogawa Electric Corporation.

The film for preventing impurities is formed by cleaning the anodic oxide film formed on the aluminum metal material using an ultrasonic method and / or an electrolytic method, or a combination of this method with a vibration method, a submerged water method, etc., and then dry and / or wet. Apply far-infrared irradiation after treatment, or perform sealing treatment at room temperature, boiling water, steam or metal salt before dry and / or wet far-infrared irradiation, and then perform far-infrared irradiation. Is preferred. Furthermore, the sealing treatment can be performed using one or more inorganic compounds or organic compounds. The dry far-infrared irradiation referred to here means far-infrared irradiation in the dry state in the air or atmosphere, and the wet far-infrared irradiation refers to the surface of the material to be treated in a liquid and / or atomized atmosphere with water or a compound. Far-infrared irradiation.

In the present invention, the anodic oxide film is cleaned by ultrasonic cleaning, flowing water cleaning, AC electrolytic cleaning, or a combination thereof. A cleaning method called a reverse electric method may be used as the electrolytic cleaning method. When these cleaning methods are used, the impurity elution amount can be made to be equal to or less than the amount specified in the present invention, but the ion elution amount cannot be reduced in this way by another cleaning method.

The specific method of sealing treatment is to clean the fine pores present in the anodic oxide film by the above method, and then, if necessary, pure water or aluminum-based, aluminate-based, silicate-based, 70 ° C. or higher, 5-30 in a bath in which one or two or more of acetates, citrates, tartrates, and amines such as silicofluoride, fluoride, borofluoride, and fluorosilicic acid are combined. Pseudo-hydrates are made, and pseudo-hydrates are formed. Further, pseudo-hydrates are changed to hydrates in pure water at 90 ° C. or higher, and then hydrated by post-treatment by dry and / or wet far-infrared irradiation. 1 part and / or pseudocrystal of the product. The anodic oxide film thus formed acts as a film for preventing impurities from elution, and the conductivity of pure water when immersed in pure water at 60 ± 1 ° C. for 360 hours is about 5 μS / cm / 18 cm ² or less. It becomes.

The components constituting the impurity elution preventing film are 80% to 99.9% aluminum oxide and / or aluminum hydroxide as the main components, and the remaining 0.01 to 20% are film auxiliary components. It is composed of one or more selected from acid salts, silicofluorides, fluorides, borofluorides, and fluorines.

Films produced by anodization of aluminum alloys usually have a cell structure consisting of innumerable fine pores, and this cell structure that has been sealed is often used for known applications. elution amount 60 ° C., 360 hours becomes 20~30μS / cm / 18cm ² of about conductivity at the time of operation, future products adverse effects is too large impurity elution coming up packing density greater when used in a semiconductor device It is difficult to put it to practical use.

The anodized film on the surface of the aluminum metal part in the present invention is mainly composed of an amorphous aluminum oxide, and this is combined with one or more sealing holes at room temperature, boiling water, steam or metal salt. Then, after further treatment by far-infrared irradiation by dry and / or wet, the process proceeds to a mixed state of amorphous and pseudo-crystals close to crystals. As a result, the structure is more stable than amorphous so that the elution of impurities is significantly smaller than that of conventionally known alumite.

As well known, the anodic oxidation treatment includes a single bath with sulfuric acid, oxalic acid or the like, a mixed acid bath thereof, or a mixed bath with an organic acid for electrolytic coloring. On the other hand, as a multiple bath electrolysis method, there is an electrolytic coloring method in which secondary electrolysis is performed after sulfuric acid electrolysis. These are colors. However, with regard to the electrical conductivity, which is the object of this time, the conductivity increases due to the elution of impurities into the solvent from the pores of the porous structure, which is a drawback of the aluminum anodized film.

In the present invention, in order to prevent impurities, it is essential to efficiently remove impurities in the pores, reduce the volume of the pores, and stabilize the coating. Various cleaning methods are known as impurity removal methods, and there are known sealing methods, pseudo-crystallization methods, and pore feeling methods for reducing the pore volume. In a general sealing method, the surface layer film becomes a hydrate, and the surface expands in volume, so the diameter of the inlet (surface side) becomes smaller and the size of the inner diameter is almost unchanged. Rather, it tends to hinder the cleaning of the porous pores. In addition, since the pore diameter at the entrance (surface side) is small, impurities inside the pores tend to elute into the solvent for a long time, which is not suitable. In the pore feeling method, the pores are certainly filled, but when immersed in a solvent, impurities are eluted.

From these points, the present invention was assembled as a solving means by dividing the film into a production process, a cleaning process, a process of filling holes, a process of sealing, and a stabilization process. In particular, in the film formation process, paying attention to the cleaning of the porous pores, the order of electrolysis according to the pore size of the electrolytic bath is determined, and even with the same coating thickness, the pore size of the electrolytic bath can be easily cleaned. In view of the difference, it features a multiple electrolysis method with film growth. The cleaning method according to the present invention requires electrolytic cleaning by an ultrasonic method, a reverse electric method, or an alternating current method. Further, the sealing method includes a combination of an electrolytic coloring method, a pore feeling method, a sealing method that hardly dissolves in a solvent, and a far-infrared irradiation method in order to reduce the pore volume. The combination of the multiple electrolysis method, the cleaning method, the multiple sealing method and the post-treatment achieves the conductivity to the target value.

As a preferred method of anodizing treatment, there is a multi-bath anodic oxide film treatment method, which is a sulfuric acid method or an inorganic electrolytic method of a phosphoric acid method. Continuously combining one or two or more electrolysis methods of an organic electrolysis method including an aliphatic or aromatic organic compound having two or more, a mixed acid electrolysis method combining an inorganic electrolysis bath and an organic electrolysis bath This is a production method using a multi-type multi-stage electrolytic bath method.

The metal material of the present invention was a film that could not be achieved with conventional alumite products when used as a part in a field where contamination is particularly afflicted with semiconductor devices, etc. There is a possibility that the improvement of the packaging density can contribute to the solution of the problem from this point.

Next, examples of the present invention will be described.

After degreasing, etching, desmutting of aluminum alloy (A6061, 25 cm ² on one side), first electrolysis; sulfuric acid bath (free sulfuric acid concentration 130 g / L, dissolved aluminum concentration 5 g / L, bath temperature 21 ° C., voltage 14 V,) After treatment for 30 minutes, washing with ultrasound for 5 minutes, electrolytic washing (AC 12V, sodium silicofluoride 7 g / L, 20 ° C., 10 minutes), further washing with ultrasound for 5 minutes, and boiling water temporary sealing (80 C., 5 minutes), steam sealing (0.5 MPa, 15 minutes) was performed, and drying was performed by irradiating far infrared rays for 30 minutes in a batch type far infrared furnace using an Infrastein B heater manufactured by NGK Kiln Tech Co., Ltd. The film thickness was 10 ± 1 μm, and the salt spray test was performed for 360 hours. N. It was 9.8 or more. When immersed in 500 ml of pure water having a purity of 1 μS / cm at 60 ° C. for 360 hours and measured with a conductivity meter SC82 manufactured by Yokogawa Electric Corporation, it was 3.4 μS / cm / 18 cm ² .

The same treatment as in Example 1 was performed under the same pretreatment and electrolysis conditions, and after washing was performed by a flowing water immersion method, ultrasonic cleaning was further performed for 10 minutes, and after boiling water was temporarily sealed, the same as in Example 1 In the far-infrared furnace, the surface was irradiated with far-infrared rays in a vapor mist for 15 minutes, and then subjected to ultrasonic cleaning again for 10 minutes. The film thickness is 10 ± 1 μm, salt spray test 360 hours R.D. N. It was 3.6 μS / cm / 18 cm ² when measured with a conductivity meter SC82 manufactured by Yokogawa Electric Corporation after immersing in pure water at 60 ° C. for 360 hours at 9.8 or higher.

The same treatment as in Example 1 and the pretreatment and electrolysis conditions were performed, and after washing was performed by flowing water immersion, ultrasonic washing was further performed for 10 minutes, and then sealing by dry far infrared irradiation was performed. It was performed for 15 minutes, and further ultrasonic cleaning was performed for 10 minutes. The film thickness was 10 ± 1 μm, and the salt spray test was performed for 360 hours. N. Was 9.8 or more. When immersed in pure water at 60 ° C. for 360 hours and measured with a conductivity meter SC82 by Yokogawa Electric Corporation, it was 3.8 μS / cm / 18 cm ² .

The same treatment as in Example 1 was performed under the same pretreatment and electrolysis conditions, and after washing was performed by a flowing water immersion method, electrolytic washing (AC 13 V, sulfuric acid 0.05 mol / L, 20 ° C., 10 minutes) Further, ultrasonic cleaning was performed for 10 minutes, far-infrared irradiation in the atmosphere was performed for 30 minutes, and ultrasonic cleaning was further performed for 10 minutes. The film thickness was 10 ± 1 μm, and the salt spray test was performed for 360 hours. N. Was 9.8 or more. When immersed in pure water at 60 ° C. for 360 hours and measured with a conductivity meter SC82 by Yokogawa Electric Corporation, it was 3.5 μS / cm / 18 cm ² .

The same treatment as in Example 1 was performed under the same pretreatment and electrolysis conditions, and washing was performed by a flowing water immersion method, followed by room temperature sealing (Econo Seal 2S; manufactured by Evatech, 10 g / L, 28 ° C., 10 ° C. Minute), ultrasonic cleaning was performed for 10 minutes, far-infrared irradiation in the atmosphere was performed for 30 minutes, and ultrasonic cleaning was performed for 10 minutes. The film thickness was 10 ± 1 μm, and the salt spray test was performed for 360 hours. N. Was 9.8 or more. 60 ° C. in pure water, was measured at 360 hours after dipping Yokogawa Electric Corporation conductivity meter SC82, was 3.7μS / cm / 18cm ^2.

(Comparative example 1) After processing with the to-be-processed object and pre-processing and electrolysis conditions similar to Example 1, and performing washing | cleaning by a flowing water immersion method, the place where boiling water sealing was performed, the film thickness is 10 +/-. 1 μm, salt spray test 360 hours R.D. N. Although it was 9.8 or more, it was 8.1 μS / cm / 18 cm ² when measured with a conductivity meter SC82 by Yokogawa Electric Corporation after being immersed in pure water at 60 ° C. for 360 hours.

(Comparative example 2) After processing with the to-be-processed object and pre-processing and electrolysis conditions similar to Example 1, and washing | cleaning by a flowing water immersion method, Foucault 07 (made by Furukawa Electric; Nickel acetate sealant, 7 g / L, 93 ° C., 15 minutes). The film thickness is 10 ± 1 μm, salt spray test 360 hours R.D. N. It was 9.8 or more. After being immersed in pure water at 60 ° C. for 360 hours, measured with a conductivity meter SC82 by Yokogawa Electric Corporation, it was 10.4 μS / cm / 18 cm ² .

(Comparative Example 3) Using the same treatment as in Example 1, and performing the same pretreatment, a mixed acid bath (free sulfuric acid 120 g / L, free oxalic acid 10 g / L dissolved aluminum 4 g / L) was used as an electrolytic bath. The sample was subjected to electrolytic treatment at a bath temperature of 5 ° C. and a direct current density of 1.2 A / dm ² for 30 minutes, washed with running water for 10 minutes and then dried at low temperature without sealing. The film thickness is 10 ± 1 μm, salt spray test 360 hours R.D. N. It was 9.8 or more. When immersed in pure water at 60 ° C. for 360 hours and measured with a conductivity meter SC82 by Yokogawa Electric Corporation, it was 13.3 μS / cm / 18 cm ² .

The aluminum product of the present invention is used in a semiconductor device that requires weight reduction or a part or component that dislikes impurity elution in a film.

Claims (4)

An aluminum metal material having an anodized film with a small amount of impurity elution on the surface, the impurity elution amount defined in the text from the anodized film to the solvent is 5 μS / cm or less in electrical conductivity, and has corrosion resistance. Salt spray test 360 hours R.D. N. Aluminum material characterized by having 9.5 or more The main component of the anodized film is 80% to 99.9% composed of aluminum oxide or aluminum hydroxide alone or a mixture thereof, and 0.01 to 20% is silicate-based, silicofluoride-based, fluoride. 2. The aluminum material according to claim 1, wherein the aluminum material is made of a film auxiliary component composed of one or more selected from the group consisting of fluorinated, fluorinated and fluorinated metal salts. Aluminum and aluminum alloys are subjected to anodization at least once in one or more combined baths of one or more inorganic acid baths or organic acid baths, electrolysis and / or ultrasonic Post-treatment by dry and / or wet far-infrared irradiation after cleaning by the method, or post-treatment in combination with dry and / or wet far-infrared irradiation and one or more sealing at normal temperature, boiling water, steam or metal salt 3. The method for producing an aluminum material according to claim 1, wherein the aluminum material is applied. 4. The method for producing an aluminum material according to claim 3, wherein the anodizing treatment is performed by a direct current method or a pulse method film formation, and the cleaning method is performed by a multiple electrolysis method comprising two or more stages combining a reverse electric method and an alternating current method.