JP2012011520A - Electrolytic processing liquid for molybdenum-based metallic material, and method for manufacturing molybdenum-based metallic product using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device that electrolytically machines a molybdenum-based metallic material without using a poisonous substance.SOLUTION: An electrolytic processing liquid for a molybdenum-based metallic material, is formed through dissolving an electrolyte selected from a group consisting of an alkali metal chloride and an alkaline-earth metal chloride, and a citric acid with an aqueous solvent containing a glycol-based compound.

Description

The present invention relates to an electrolytic machining fluid for molybdenum-based metal materials such as molybdenum and molybdenum alloys, and more particularly, molybdenum that enables electrolytic polishing and electrolytic etching of molybdenum-based metal materials without using poisonous substances. The present invention relates to an electrolytic processing liquid for a metallic metal material.
The present invention further relates to a method for producing a molybdenum-based metal product using the electrolytic processing liquid.

  Molybdenum (Mo) is a heat-resistant material with a high melting point, and is therefore widely used in various applications that require high heat resistance. For example, the aperture used to adjust the electron beam diameter in an electron microscope is exposed to high temperature due to the electron beam, and many of them are manufactured by making fine holes in a molybdenum foil. In the processing, electrolytic etching processing using electric discharge processing or a photo process is used because of the thinness of the molybdenum foil and the required accuracy. Electrolytic etching has become an important method of aperture processing in recent years because it has a lower processing cost than electric discharge machining.

  In general, an aqueous solution containing chromic acid or sulfuric acid is used as the electrolytic processing liquid for molybdenum-based metal materials, but both chromic acid and sulfuric acid are designated as deleterious substances, so there are problems in workability, cleaning, and waste liquid treatment. I have it.

  On the other hand, Non-Patent Document 1 reports that the molybdenum foil can be subjected to electrolytic etching with an electrolytic processing solution that does not contain chromic acid (chromium-free).

Exit, Outer: Development of micro-hole processing technology for electron microscope apertures-Electrolytic etching of molybdenum foil-, Saitama Industrial Technology Center Research Report, 7, (2009) 70

  The electrolytic processing solution described in Non-Patent Document 1 is an aqueous solution containing ethylene glycol and sulfuric acid, and enables electrolytic processing (electrolytic etching processing) of a molybdenum foil without using chromic acid. However, since the sulfuric acid contained in the above-mentioned chromium-free electrolytic processing liquid is also a deleterious substance, from the viewpoint of workability, cleaning, and waste liquid treatment, the electrolysis of molybdenum with a poisonous and deleterious-free electrolytic processing liquid that does not contain chromic acid or sulfuric acid. It is desirable to enable processing.

  Accordingly, an object of the present invention is to provide a means for enabling electrolytic processing of a molybdenum-based metal material without using poisonous or deleterious substances.

As a result of intensive studies to achieve the above object, the present inventor has obtained the following new knowledge.
First, in order to achieve the above-mentioned object, the present inventor, from an alkali metal chloride and an alkaline earth metal chloride, which are highly safe salts, to an aqueous solvent containing a non-flammable and highly safe glycol-based compound. When we tried electrolytic processing (electrolytic polishing processing, electrolytic etching processing) of molybdenum-based metal materials using an electrolytic processing solution in which an electrolyte selected from the group was dissolved, electrolytic processing was possible, but electrolytic processing A phenomenon in which the liquid was noticeably clouded was confirmed. This was caused by bubbles generated at the cathode during electrolytic processing floating in the liquid. However, the generation of bubbles in electrolytic processing was caused by the bubbles staying in the part to be processed and machining accuracy (for example, through holes in electrolytic etching processing). Therefore, there is a need for an electrolytic processing solution that enables electrolytic processing without causing white turbidity.
Therefore, as a result of extensive studies by the inventor in order to suppress white turbidity due to bubbles in the electrolytic processing liquid having the above composition system, the liquid turbidity during electrolytic processing can be obtained by adding citric acid, which is a highly safe organic acid. It has been found that can be suppressed. On the other hand, organic turbidity other than citric acid or inorganic acid could not suppress white turbidity.
As a result of the above examination, the present inventor dissolved citric acid in an aqueous solvent containing a glycol compound together with the above highly safe electrolyte without using a poisonous or deleterious substance, The inventors have found that it is possible to electrolytically process a molybdenum-based metal material while suppressing white turbidity.

That is, the above object was achieved by the following means.
[1] An electrolytic processing solution for molybdenum-based metal materials, in which an electrolyte selected from the group consisting of alkali metal chlorides and alkaline earth metal chlorides and citric acid are dissolved in an aqueous solvent containing a glycol compound.
[2] The electrolytic processing liquid for molybdenum-based metal material according to [1], wherein the content of water in the solvent is 50% by volume or less.
[3] The electrolytic processing liquid for molybdenum-based metal material according to [1] or [2], wherein the citric acid content is in the range of 0.08 to 2.4 mol / l.
[4] The electrolytic processing liquid for molybdenum-based metal material according to any one of [1] to [3], wherein the glycol-based compound is ethylene glycol.
[5] The electrolytic processing liquid for molybdenum-based metal material according to any one of [1] to [4], which is used as an electrolytic polishing liquid.
[6] The electrolytic processing liquid for molybdenum-based metal material according to any one of [1] to [4], which is used as an electrolytic etching liquid.
[7] Molybdenum having a polished surface on the surface, wherein the molybdenum-based metal material is used as an anode, and the electrolytic polishing treatment is performed using the electrolytic processing solution according to any one of [1] to [4] as an electrolytic polishing solution. Of manufacturing metal products.
[8] A step of applying a resist to the surface of the molybdenum-based metal material;
Exposing the resist through a photomask to form a pattern portion; and
Removing a part of the molybdenum-based metal material surface by removing the pattern portion or the resist other than the pattern portion; and
Forming a recess and / or a through hole by corroding the exposed surface;
Removing the resist on the surface of the molybdenum-based metal material, and a method for producing a molybdenum-based metal product having a recess and / or a through-hole,
The exposed surface is corroded by electrolytic etching using the molybdenum-based metal material as an anode and the electrolytic processing liquid according to any one of [1] to [4] as an electrolytic etching liquid. The manufacturing method.

  ADVANTAGE OF THE INVENTION According to this invention, a molybdenum metal material can be electrolytically processed using the highly safe electrolytic processing liquid which does not contain poisonous and deleterious substances and does not have flammability. Furthermore, the electrolytic processing solution using citric acid is advantageous in that it is easy to handle without a strong irritating odor.

It is explanatory drawing which shows the outline of the one aspect | mode of the manufacturing method of the molybdenum-type metal product of this invention. The structure of an electrolytic processing apparatus is shown. It is explanatory drawing of an electropolishing sample. It is a digital camera photograph which shows the state of the sample after the electrolytic treatment of Example 1. FIG. 2 is a digital camera photograph in which the state of an electrolytic solution during electrolytic treatment of Comparative Example 1 and Example 1 is photographed. It is the digital camera photograph which image | photographed the state of the electrolyte solution during the electrolytic treatment of Comparative Examples 2-4. The result obtained in Example 11 is shown. It is explanatory drawing of an electrolytic etching sample. It is a scanning electron micrograph of the processing surface in Example 12 (magnification 100 times). It is a scanning electron micrograph (400-times multiplication factor) of the processing surface in Example 12.

[Molybdenum-based metal electrolytic processing fluid]
The electrolytic processing liquid of the present invention is used for electrolytic processing of a molybdenum-based metal material, and is selected from the group consisting of an alkali metal chloride and an alkaline earth metal chloride as an aqueous solvent containing a glycol compound. The electrolyte and citric acid are dissolved. The electrolytic processing liquid of the present invention enables electrolytic processing of a molybdenum metal material without using deleterious chromic acid and sulfuric acid. An electrolyte selected from the group consisting of highly safe alkali metal chlorides and alkaline earth metal chlorides and citric acid, which is a highly safe organic acid, are dissolved in an aqueous solvent containing a non-flammable glycol compound. Therefore, it has the advantage that it has extremely high safety and is easy to handle without a strong pungent odor. Furthermore, it is possible to suppress the cloudiness of the liquid during electrolytic processing.
Hereinafter, the electrolytic processing liquid of the present invention will be described in more detail.

  The electrolytic processing liquid of the present invention can be used for various electrolytic processing for dissolving the surface of a metal material by electrolysis. Specific examples of the electrolytic processing include electrolytic polishing processing and electrolytic etching processing, and details thereof will be described later.

  The metal material to be electrolytically processed in the present invention is a molybdenum-based metal material, pure molybdenum or titanium zirconia molybdenum alloy, molybdenum hafnium carbide, molybdenum lanthanum alloy, molybdenum yttrium alloy, and other various molybdenum alloys containing molybdenum as a metal component. Can be mentioned. As described above, as the electrolytic processing fluid of such a molybdenum-based metal material, a material containing chromic acid or sulfuric acid, which is a deleterious substance, has been conventionally used. On the other hand, according to the present invention, it is possible to provide an electrolytic machining liquid for molybdenum-based metal material that is excellent in safety as described below and can suppress white turbidity of the liquid during electrolytic machining. The electrolytic processing liquid of the present invention is suitable for application to a metal material having a high molybdenum content, and is suitable for application to a high-purity molybdenum-based metal material containing molybdenum of 90% by mass or more, and further 95% by weight or more. Is.

  The solvent of the electrolytic processing liquid of the present invention is an aqueous solvent containing a glycol compound. The aqueous solvent means a solvent containing water, and a mixed solvent composed of water and a glycol solvent is preferable from the viewpoint of safety. The water content in the aqueous solvent is preferably 50% by volume or less from the viewpoint of obtaining a smooth processed surface with a mirror finish (high glossiness). From the viewpoint of processing speed, the water content in the aqueous solvent is preferably 10% by volume or more, and more preferably 20% by volume or more. From the viewpoint of processing quality and processing speed, in the mixed solvent composed of water and glycol solvent, the mixing ratio of water and glycol solvent is glycol solvent: water (volume ratio) = 2: 1 to 1: 1. A range is preferable.

  Examples of the glycol compound (glycol solvent) contained in the aqueous solvent include glycol compounds represented by the following general formula (I). Preferable specific examples from the viewpoint of processing accuracy include ethylene glycol, diethylene glycol, or propylene glycol, and most preferably ethylene glycol. In the present invention, glycol compounds may be used alone or in combination of two or more.

(In the formula, R is a hydrogen atom or a methyl group, preferably a hydrogen atom. N is an integer in the range of 1 to 3, preferably an integer in the range of 1 to 2.)

  The electrolytic processing liquid of the present invention contains an electrolyte selected from the group consisting of alkali metal chlorides and alkaline earth metal chlorides, which are highly safe salts. Specifically, examples of the alkali metal chloride include sodium chloride, lithium chloride, and potassium chloride, and examples of the alkaline earth metal chloride include calcium chloride and strontium chloride. In the present invention, two or more alkali metal chlorides and alkaline earth metal chlorides can be used in combination. The concentration of the electrolyte in the electrolytic processing solution of the present invention is preferably set in consideration of the solubility of the electrolyte used in the aqueous solvent. From the viewpoint of processing quality, the concentration of the electrolyte is preferably 50 g or more, more preferably 65 g or more, more preferably 100 g or more, and more preferably 130 g or more with respect to 1 liter of solvent. Is even more preferred. The concentration in terms of mol / l is preferably 0.85 mol / l or more, and more preferably 1.5 mol / l or more. As shown in the examples described later, in order to obtain a smooth processed surface with a mirror finish (high glossiness), it is preferable to increase the electrolyte concentration. However, if the electrolyte is added exceeding the saturation concentration, the electrolytic processing solution is chlorinated. Since an object may precipitate and processing precision may fall, it is preferable that the density | concentration of an electrolyte shall be a saturation density or less.

  The electrolytic processing liquid of the present invention is obtained by dissolving citric acid together with the electrolyte in the aqueous solvent. By containing citric acid, the clouding of the liquid during electrolytic processing can be suppressed. From the viewpoint of effectively suppressing the white turbidity, the content of citric acid in the electrolytic processing liquid of the present invention is preferably 0.08 mol / l or more, more preferably 0.15 mol / l or more. preferable. Further, from the viewpoint of processing speed, the content of citric acid in the electrolytic processing liquid of the present invention is preferably 2.4 mol / l or less, more preferably 0.60 mol / l or less, and More preferably, it is 40 mol / l or less. In addition, although content of the said citric acid was shown on the anhydrous citric acid reference | standard, of course, it is also possible to adjust an electrolytic processing liquid using a citric acid hydrate in this invention.

  The electrolytic processing solution of the present invention is prepared by dissolving an electrolyte selected from the group consisting of alkali metal chlorides and alkaline earth metal chlorides and citric acid in the aqueous solvent, In addition, a known additive can be included, but it is basically composed of the components described above. Since citric acid is included, the liquidity is usually acidic, and the pH is preferably about 1 to 3. A molybdenum-based metal product having high glossiness can be provided by using the electrolytic processing liquid of the present invention as an electrolytic polishing liquid, and a molybdenum-based metal product etched into a desired shape by using the electrolytic processing liquid as an electrolytic etching liquid. Can be provided. Details of the electrolytic processing using the electrolytic processing liquid of the present invention will be described later.

[Method of manufacturing molybdenum metal products]
The first aspect of the method for producing a molybdenum-based metal product of the present invention (hereinafter referred to as “Method 1”) is to obtain a molybdenum-based metal material having a polished surface on the surface by performing electrolytic polishing treatment.
The second aspect of the method for producing a molybdenum-based metal product of the present invention (hereinafter referred to as “Method 2”) is to obtain a molybdenum-based metal product having recesses and / or through holes by electrolytic etching treatment.
Hereinafter, details of the method 1 and the method 2 will be sequentially described.

Method 1
Method 1 is a method for producing a molybdenum-based metal product having a polished surface on the surface, and performs an electrolytic polishing process using a molybdenum-based metal material as an anode and the electrolytic processing liquid of the present invention as an electrolytic polishing liquid. The surface to be polished may be a part or all of the surface of the metal material. In order to perform a partial polishing process, an electrolytic polishing process is performed after masking a part other than the polishing target part with a tape or the like. Just do it.

  In Method 1, the metal material to be polished can be used as an anode, and the electrolytic processing solution of the present invention can be disposed between the anode and the cathode to perform the electrolytic polishing process. Specifically, the electrolytic polishing treatment can be performed by immersing the anode and the cathode in the electrolytic processing solution of the present invention.

  The material of the cathode is not particularly limited, and examples thereof include titanium, platinum, stainless steel, and copper. Further, the shape of the cathode is not particularly limited, and is preferably a shape in which current flows uniformly according to the shape of the metal material to be polished, for example, a flat plate shape. As described above, since the electrolytic processing liquid containing citric acid is used in the present invention, bubbles generated at the cathode during the electrolytic polishing process can be prevented from floating in the liquid and the liquid becoming cloudy.

The electrolytic polishing treatment can be performed by a known method, and the electrolytic conditions are preferably determined in consideration of a desired polishing amount and the state of the polished surface (for example, glossiness). For example, the electrode voltage can be 5 to 40 V, the current density can be 100 to 800 mA / cm ² , and the electrolytic treatment time can be about 1 to 60 minutes. Here, the “interelectrode voltage” refers to the voltage between the anode (workpiece) and the cathode (electrode). The applied current may be direct current or alternating current. Moreover, the temperature of the electrolytic processing liquid at the time of performing an electropolishing process can be about normal temperature (room temperature), for example, and it is preferable to set it as the range of 5-40 degreeC. The electropolishing treatment may be performed under constant conditions, or may be performed while changing electrolysis conditions such as the interelectrode voltage continuously or stepwise. In addition, all steps may be performed continuously without suspending electrolysis, and it is also possible to provide a period of cessation. If foreign matter adheres to the polished surface during the polishing process, removing the foreign matter from the polished surface by temporarily stopping the electrolysis and stirring the liquid or vibrating the workpiece improves polishing efficiency. It is effective in.

  By the method 1 demonstrated above, the molybdenum-type metal product which has the grinding | polishing surface in which the glossiness improved compared with before a process can be obtained. The molybdenum-based metal material in method 1 and method 2 described later is as described above for the electrolytic processing liquid of the present invention.

Method 2
Method 2 includes a step of applying a resist to the surface of a molybdenum-based metal material (hereinafter referred to as “first step”), and a step of exposing the resist through a photomask to form a pattern portion (hereinafter referred to as “first step”). Two steps), a step of exposing a part of the surface of the molybdenum-based metal material by removing the pattern portion or the resist other than the pattern portion (hereinafter referred to as “third step”), and the exposed surface. The step of forming recesses and / or through holes by corroding (hereinafter referred to as “fourth step”) and the step of removing the resist on the surface of the molybdenum-based metal material (hereinafter referred to as “fifth step”) And a molybdenum-based metal product having a recess and / or a through-hole, the corrosion of the exposed surface, and the molybdenum-based metal material as an anode And, it is performed by electrolytic etching the electrolytic processing solution as an electrolytic etching solution of the present invention.
Hereinafter, details of the method 2 will be described with reference to FIG.

FIG. 1 is an explanatory diagram showing an outline of the method 2.
First, a resist is applied to the surface of the molybdenum-based metal material (first step: FIG. 1A). Next, by exposing the resist through a photomask, the pattern of the photomask is transferred onto the resist (second step: FIG. 1B). Thereafter, a portion of the surface of the molybdenum-based metal material is exposed by removing a portion of the resist to which the pattern has been transferred (third step: FIG. 1C).
The first step, the second step, and the third step can be performed using a known photolithography technique that is widely used in electrolytic etching.

  In the present invention, a known resist can be used as the resist. The resist may be applied to only one surface of the metal material, but when forming the through hole, it is preferable to apply the resist to both surfaces of the metal material and form the same pattern on the upper and lower surfaces. In the electrolytic etching process, the diameter tends to decrease as the etching progresses inside. Therefore, in order to form a through hole having a uniform diameter, it is preferable to form the same pattern on the upper and lower surfaces and perform etching from both surfaces of the metal material. In addition, when applying a resist only to one side, what is necessary is just to perform well-known nonelectroconductive processes, such as nonconductive masking, so that the other surface may not be etched in an electrolytic process.

  In the second step, as the light source, a light source corresponding to the resist used, such as ultraviolet rays, can be used. In the second step, the pattern of the photomask is transferred onto the resist to form a pattern portion. Note that an unexposed portion where exposure is blocked by the photomask becomes a pattern portion.

Thereafter, the resist in the pattern portion (unexposed portion) or other than the pattern portion (exposed portion) is removed to expose a part of the surface of the metal material. The resist can be removed by a known development method. The developer may be appropriately selected according to the resist to be used. When a positive resist is used as the resist, the exposed portion of the resist is removed by development, and when a negative resist is used, the unexposed portion of the resist is removed by development.
Through the above steps, the surface of the metal material can be exposed at a position where the recess and / or the through hole is desired to be formed.

Next, the fourth step will be described.
The fourth step is a step of forming a recess and / or a through hole by corroding the exposed surface (FIG. 1 (d)). In this step, the exposed surface is corroded by electrolytic etching using the molybdenum-based metal material as an anode and the electrolytic processing solution of the present invention as an electrolytic etching solution. Specifically, the metal material with a part of the surface exposed in the third step can be used as an anode, and the electrolytic processing solution of the present invention can be placed between the anode and the cathode to perform electrolytic etching treatment. . More specifically, the electrolytic etching process can be performed by immersing the anode and the cathode in an electrolytic processing solution. In this step, the exposed surface is corroded and the metal is removed in the depth direction, whereby a recess and further a through hole can be formed. The cathode material and shape are as described for Method 1 above.

In the electrolytic etching process, a recess is formed in the processed surface, and the etching progresses by gradually deepening the processed surface, thereby forming a recess and a through hole. The electrolytic etching treatment in Method 2 can be performed by a known method, and the electrolysis conditions can be appropriately set according to the metal material to be processed and the shape (diameter, depth, etc.) of the desired recess and through hole. it can. For example, the electrode voltage can be 3 to 40 V, and the current density can be 25 to 800 mA / cm ² . What is necessary is just to set the electrolytic treatment time according to the thickness of a metal material, the shape of a desired recessed part, a through-hole, etc., for example, can be 1 to 60 minutes. Other details of the electrolytic treatment are as described above for Method 1.

Next, after the formation of the recesses and / or the through holes in the fourth step, the resist remaining on the surface of the metal material is removed (fifth step: FIG. 1E). The resist removal can be performed by a known method using a resist stripping solution or a solvent such as acetone corresponding to the resist to be used.
Through the above steps, a molybdenum metal product having a recess and / or a through hole can be obtained.

The present invention is applicable to various metal products to which molybdenum metal materials are applied, for example, electronic devices such as semiconductor devices, optical devices, and chemical devices. Moreover, the metal product in which the through-hole was formed by the method 2 can be a filter, an aperture, etc., for example.
According to the present invention, the molybdenum-based metal product can be manufactured using a highly safe electrolytic processing liquid, and the electrolytic processing liquid can prevent liquid turbidity during electrolytic processing.

  The present invention will be further described below based on examples. However, the present invention is not limited to the embodiment shown in the examples.

1. Examples of electropolishing and comparative examples

1-1 Confirmation of citric acid addition effect [Examples 1 to 3, Comparative Example 1]
(1) Electrolytic processing apparatus The structure of an electrolytic processing apparatus is shown in FIG.
A DC power source (maximum current 5 A) was used as the power source. A glass square container (100 mm × 100 mm × 100 mm) was used for the electrolytic cell, and the electrolytically processed sample (anode) was arranged at the center of the cell. As the electrode (cathode), a stainless steel plate (SUS304, plate thickness 0.2 mm) was disposed along the wall surface of the rectangular container (the surface facing the surface to be processed). The electrolytic processing apparatus used in the examples of the electrolytic etching process described later has the same configuration, but differs in that the electrodes are arranged on two opposing surfaces in order to perform electrolytic etching from both sides.

(2) Electropolishing sample A pure molybdenum plate (0.50 mm thickness x 100 mm x 500 mm, purity 99.95% (mass%)) processed from a pure molybdenum plate into a strip shape (width 15 mm) in ethanol using a shearing machine After ultrasonic cleaning, the polishing area (50 mm × 15 mm) was adjusted by masking with a fluororesin tape (Nitoflon adhesive tape manufactured by Nitto Denko Corporation) as shown in FIG.

(3) Preparation of electrolytic processing liquid The electrolytic processing liquid was prepared by dissolving citric acid monohydrate in the amount shown in Table 1 in an aqueous solution prepared by dissolving 60 g of sodium chloride in 600 ml of a mixed solvent of 300 ml of ethylene glycol and 300 ml of water. Prepared.

(4) Electropolishing treatment Using the electrolytic polishing liquid prepared in the above (3), constant voltage electrolysis was performed for 3 minutes at a liquid temperature of 20 ° C. and an interelectrode voltage of 20 V using the electrolytic processing apparatus shown in FIG. Table 1 shows the presence or absence of cloudiness of the liquid during the electrolytic treatment.

(5) Measurement of reduction in sheet thickness At five polishing portions, the plate thickness before and after the polishing treatment was measured with a micrometer, and the average value was calculated. (Average value of plate thickness before polishing treatment) − (Average value of plate thickness after polishing treatment) was defined as the thickness reduction.

(6) Glossiness In gloss meter VGS-300A (Nippon Denshoku Co., Ltd.), based on the specular gloss measurement method (JIS Z8741), measure the central part of the polished surface four times at a measurement angle of 60 °, and calculate the average value. Calculated. When the specular gloss before polishing treatment was measured by the above method, it was 158.

As shown in Table 1, in Examples 1 to 3 and Comparative Example 1, it can be confirmed that the electrolytic polishing treatment of molybdenum became possible without using chromic acid and sulfuric acid because the plate thickness was reduced by the electrolytic treatment. In addition, since the mirror glossiness can be increased by the polishing treatment, it can also be confirmed that the mirror polishing can be performed by the electrolytic treatment. As a representative example, a digital camera photograph showing the state of the sample after the processing of Example 1 is shown in FIG.
However, in Comparative Example 1 in which an electrolytic processing solution containing no citric acid was used, the solution became significantly cloudy during the electrolytic treatment. For comparison, FIG. 5 shows a digital camera photograph of the state of the electrolytic solution during the electrolytic treatment of Comparative Example 1 and Example 1. When the inside of the apparatus during the electrolytic treatment of Comparative Example 1 was visually observed, a large amount of bubbles were generated from the cathode surface, and it was confirmed that the cause of white turbidity was bubbles generated at the cathode. The generation of bubbles in the electrolytic processing may cause the bubbles to stay in the portion to be processed and deteriorate the processing accuracy.
On the other hand, as shown in the lower diagram of FIG. 5, in Example 1, the liquid did not become cloudy during the electrolytic treatment. Also in Examples 2 and 3, the electrolytic solution during the electrolytic treatment was in the state shown in the lower diagram of FIG. 5, and no cloudiness was observed. From the above results, it was shown that the white turbidity of the solution during the electrolytic treatment can be suppressed by adding citric acid.

[Examples 4 and 5]
The same treatment and evaluation as in the above example were performed, except that the electrolytic treatment was performed using the electrolytic processing solution and the electrolytic conditions shown in Table 2 below. As in Examples 1 to 3, there was no cloudiness of the solution during the electrolytic treatment, and it was confirmed that the plate thickness was reduced and the specular gloss was improved after the polishing treatment.

[Example 6]
Electrolytic processing solution (pH 1.2) having a composition of water (300 ml) -ethylene glycol (300 ml) -calcium chloride (120 g) -citric acid monohydrate (40 g) was used, and constant voltage electrolysis was performed at an interelectrode voltage of 15 V. Was carried out for 10 minutes (liquid temperature 20 ° C.), and the cloudiness of the liquid during the electrolytic treatment was not confirmed. Further, the specular gloss measured by the above method was 532, and it was confirmed that the mirror surface was processed.

[Comparative Example 2]
The same treatment and evaluation as in Examples 1 to 3 were performed except that 5 ml of hydrochloric acid was used as the acid instead of citric acid (pH 0.9 of the electrolytic treatment solution). The digital camera photograph which image | photographed the state of the liquid during electrolytic treatment is shown in FIG. Since the plate thickness loss was 16 μm and the specular gloss was 510, it was confirmed that the polishing was performed by electrolytic treatment. However, as shown in FIG. 6, the liquid became cloudy during the electrolytic treatment. Further, since hydrochloric acid is a deleterious substance, the electrolytic processing liquid having the above composition cannot be a poisonous and deleterious substance-free electrolytic processing liquid.

[Comparative Example 3]
The same treatment and evaluation as in Examples 1 to 3 were performed except that 30 ml of acetic acid was used instead of citric acid (pH 3.4 of the electrolytic treatment solution). The digital camera photograph which image | photographed the state of the liquid during electrolytic treatment is shown in FIG. Since the plate thickness loss was 13 μm and the specular gloss was 484, it was confirmed that the polishing was performed by electrolytic treatment. However, as shown in FIG. 6, the liquid became cloudy during the electrolytic treatment. Moreover, since acetic acid was used, the electrolytic processing liquid was disadvantageous compared to the electrolytic processing liquid used in the examples in that the pungent odor was strong.

[Comparative Example 4]
The same treatment and evaluation as in Examples 1 to 3 were performed except that 30 ml of lactic acid was used instead of citric acid (pH 3.0 of the electrolytic treatment solution). The digital camera photograph which image | photographed the state of the liquid during electrolytic treatment is shown in FIG. Since the plate thickness loss was 13 μm and the specular gloss was 490, it was confirmed that polishing was performed by electrolytic treatment. However, as shown in FIG. 6, the solution became cloudy during the electrolytic treatment. In addition, since lactic acid was used, the electrolytic processing solution was disadvantageous compared to the electrolytic processing solution used in the examples in that the pungent odor was strong.

1-2 Examination of solvent mixing ratio [Examples 7 to 10]
Using an electrolytic solution having the composition shown in Table 3 below, the constant current electrolysis is set to 3 V increments (5 V, 10 V, 15 V,..., 60 V) within a range not exceeding the maximum current 5 A of the power source using the interelectrode voltage The same treatment and evaluation as in the previous examples were performed except that the test was performed for a minute. Table 3 shows the interelectrode voltage showing the maximum specular gloss for each composition and the thickness reduction at that time.

  As shown in Table 3, since the thickness reduction was confirmed in any composition, it can be confirmed that the electrolytic polishing treatment was performed with the electrolytic processing liquid having the composition shown in Table 3. Further, in Examples 8 and 9 in which the water content in the mixed solvent was 50% by volume or less, the processing exceeding the gloss before electrolysis (mirror gloss 158) was realized. In order to obtain the surface, it can be confirmed that the content of water in the mixed solvent is preferably 50% by volume or less.

1-3 Examination of electrolyte concentration [Example 11]
In order to confirm the influence of the sodium chloride concentration on the glossiness in the composition of water (300 ml) -ethylene glycol (300 ml) -sodium chloride-citric acid monohydrate (40 g), the amount of sodium chloride was 20 g, 40 g, Electrolytic processing liquids were prepared with 60 g and 80 g. Each electrolytic processing solution was used, and the same treatment and evaluation as in the previous examples were performed except that the interelectrode voltage was set to 15 V or 20 V and constant voltage electrolysis was performed for 3 minutes. In any electrolytic treatment, since the plate thickness was reduced, it can be confirmed that the electrolytic polishing treatment was performed.
The result of the specular gloss is shown in FIG. As shown in FIG. 7, it can be confirmed that when the amount of sodium chloride is 20 g, the specular gloss is lower than that before polishing, but the specular gloss after the treatment is improved as the amount of sodium chloride is increased. Therefore, it can be said that it is preferable that the electrolyte concentration in the electrolytic processing liquid is high in order to obtain a polished surface having high glossiness. However, if an amount of electrolyte exceeding the saturation concentration is added, the deposited electrolyte may adhere to the polished surface. Therefore, the electrolyte concentration is preferably not more than the saturation concentration.

2. Example of electrolytic etching treatment

[Example 12]
Electrolytic etching treatment was performed by the following method using the electrolytic processing liquid used in Example 1. The pH of the electrolytic processing solution was 3.2.

(1) Electrolytic etching sample It patterned on both surfaces using the photoresist (SC450 by Fuji Hunt Electronics Technology company, film thickness 3 micrometers) to pure Mo foil (0.03 mm thickness). The opening diameter of the hole pattern was set to φ0.132 mm in anticipation of undercutting (side etching: progress of dissolution of the metal under the resist pattern in the lateral direction) for the purpose of processing holes of φ0.15 mm. And as shown in FIG. 8, the hole pattern was formed in the range of 25 mm x 15 mm by pitch 0.2mm. The total number of holes is about 9,000.

(2) Electrolytic processing apparatus In order to perform electrolytic etching from both sides, an electrolytic processing apparatus having the same configuration as the electrolytic processing apparatus used in the examples of the electrolytic polishing treatment was used except that the electrodes were arranged on two opposing surfaces.

(3) Electrolytic etching treatment Using the electrolytic processing liquid used in Example 1, constant voltage electrolysis was performed for 4 minutes at a liquid temperature of 20 ° C. and an interelectrode voltage of 10 V using the electrolytic processing apparatus of (2) above.
As a result of observing the processed surface with a scanning electron microscope SE-2150 (Hitachi, Ltd.), it was confirmed that a through hole having a smooth processed surface could be electrolytically etched as shown in FIGS. Moreover, when the state of the liquid during the electrolytic etching treatment was visually observed, no cloudiness was observed.

  From the above results, it has been shown that according to the present invention, it is possible to perform electrolytic processing of a molybdenum-based metal material with a poisonous and deleterious substance-free electrolytic processing liquid, and to suppress white turbidity of the liquid during electrolytic processing.

  The present invention is applicable to various fields in which molybdenum metal materials are used, such as electronic equipment, optical equipment, and chemical equipment.

Claims (8)

An electrolytic processing solution for molybdenum-based metal materials, in which an electrolyte selected from the group consisting of alkali metal chlorides and alkaline earth metal chlorides and citric acid are dissolved in an aqueous solvent containing a glycol-based compound. The electrolytic processing solution for molybdenum-based metal material according to claim 1, wherein the content of water in the solvent is 50% by volume or less. The electrolytic processing liquid for molybdenum-based metal material according to claim 1 or 2, wherein the citric acid content is in the range of 0.08 to 2.4 mol / l. The electrolytic processing liquid for molybdenum-based metal material according to any one of claims 1 to 3, wherein the glycol-based compound is ethylene glycol. The electrolytic processing liquid for molybdenum-based metal materials according to any one of claims 1 to 4, which is used as an electrolytic polishing liquid. The electrolytic processing solution for molybdenum-based metal material according to any one of claims 1 to 4, which is used as an electrolytic etching solution. Molybdenum-based metal product having a polished surface on the surface, wherein the molybdenum-based metal material is used as an anode, and the electrolytic polishing liquid according to any one of claims 1 to 4 is used as an electrolytic polishing liquid. Manufacturing method. Applying a resist to the surface of the molybdenum-based metal material;
Exposing the resist through a photomask to form a pattern portion; and
Removing a part of the molybdenum-based metal material surface by removing the pattern portion or the resist other than the pattern portion; and
Forming a recess and / or a through hole by corroding the exposed surface;
Removing the resist on the surface of the molybdenum-based metal material, and a method for producing a molybdenum-based metal product having a recess and / or a through-hole,
The corrosion of the exposed surface is performed by performing an electrolytic etching treatment using the molybdenum-based metal material as an anode and the electrolytic processing solution according to any one of claims 1 to 4 as an electrolytic etching solution. The manufacturing method.