JPH09209178A - Liquid etchant composition for stainless steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently finish a worked surface and to make a liq. etchant durable by adding a specified nitrogen-contg. compd. to the etchant. SOLUTION: This liq. etchant consists essentially of ferric chloride and contains a nitrogen-contg. composition in a specified ratio. Namely, one or >=2 kinds of nitrogen-contg. compds. selected from among groups consisting of ethylene oxide and/or propylene oxide-addition amine compd., and minocarboxylic acid and its salt and aminophosphonic acid and its salt are incorporated by 0.25-3.50wt.% into the total amt. of the liq. etchant composition. When etching is condcuted with this etchant, a good finish (glossiness, surface smoothness, pitting and side etching) is obtained. Further, since smutting is effectively prevented by this composition, smut is hardly accumulated in the liq., frothing is suppressed even when a large amt. of stainless steel is dissolved, and stainless steel is worked at a stabilized rate.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an etching solution composition used for wet etching of stainless steel.

[0002]

2. Description of the Related Art Since stainless steel is excellent in corrosion resistance and strength, it is used for various purposes in a wide range of fields including decorative parts in the art field and precision parts related to electronics. In, glossiness,
There is an increasing demand for difficult processing accuracy such as surface smoothness as well as pitting and side etching.

Usually, a stainless steel material is degreased and polished, and then, if necessary, surface-treated with about several% of acid, and a dry film is laminated as a photoresist or a liquid resist is applied and patterned, Temperature 40 to 70 ° C, pressure 1.0 to 2.5 kg / cm ²
Etching is performed under the following processing conditions.

[0004] Generally, as a stainless steel etching solution composition, a mixed solution with hydrochloric acid containing 38 to 52 degrees Baume ferric chloride as a main component, or a mixed solution to which nitric acid is further added is used. When these are used for etching processing, there is a problem that smut (surface deposit) adheres to the processed surface and impairs the finishability. Furthermore, due to the accumulation of smut due to melting of stainless steel, the life of the liquid is about 20 g /
Liquid management is performed by the amount of stainless steel dissolved around 1 liter.

For example, Japanese Patent Publication No. 3-77279 proposes an etching solution containing polyallylamine, an organic sulfur compound and an organic chelate compound as essential components.
There is a problem of re-precipitation due to melting of stainless steel materials, and pitting corrosion resistance and ease of liquid management are not sufficient.

Further, in Japanese Patent Laid-Open No. 6-73563, a chlorate selected from the group consisting of sodium chlorate, potassium chlorate and calcium chlorate in a continuous metal etching method using an aqueous solution of ferric chloride is disclosed. Hydrogen chloride 5 to 6.5 mol and ferric chloride 2.5 to 3 per 1 mol
When the chlorate aqueous solution, the hydrogen chloride aqueous solution and the ferric chloride aqueous solution are supplied to the etching solution at a ratio of 0 mol, the oxidation-reduction potential of the etching solution is detected, and the above solutions are separately used or hydrogen chloride based on the detection result. A mixed solution of an aqueous solution and an aqueous ferric chloride solution and an aqueous chlorate solution are supplied to the etching solution to continuously maintain a preset redox potential, and the hydrogen chloride concentration of the etching solution is detected. An etching method characterized by continuously supplying a hydrogen chloride aqueous solution or a hydrogen chloride aqueous solution and a ferric chloride aqueous solution to the etching solution separately or as a mixed solution based on the detection result to continuously maintain a preset hydrogen chloride concentration. Is disclosed.

[0007]

However, when stainless steel is etched by the above-mentioned generally used etching solution containing ferric chloride and hydrochloric acid as main components, smut adheres and surface finish is deteriorated. (Glossiness and surface smoothness) are impaired, and further foaming and a decrease in etching rate occur with the progress of dissolution, making continuous processing difficult.

Further, in the fine etching processing of precision parts, there is also a severe demand for an optimum etching factor to minimize the penetration into the photoresist and the side etching.

Therefore, an object of the present invention is to provide an etching solution composition capable of satisfying the finish properties (glossiness, surface smoothness, pitting corrosion, side etching) and liquid life in the etching process of stainless steel. .

[0010]

SUMMARY OF THE INVENTION In view of the above problems, the present inventors have found that in etching processing of stainless steel,
Excellent in glossiness and surface smoothness of processed surface, and pitting corrosion of inner wall,
We have conducted intensive research to find an additive with a small side etch. As a result, when an etching process was performed using an etching solution composition obtained by adding a specific nitrogen-containing compound to an aqueous solution containing ferric chloride as a main component, finish (glossiness, surface smoothness, It was found that good results can be obtained in pitting corrosion and side etching. Furthermore, since the etching solution composition containing this nitrogen-containing compound (additive) is excellent in the smut prevention effect, the smut accumulation in the bath is small, and even in the state where the dissolved amount of stainless steel is large, the foam suppressing property is obtained. It was also found that good processing with stable etching rate can be performed.

That is, the etching solution composition for stainless steel of the present invention comprises an etching solution containing ferric chloride as a main component, an ethylene oxide and / or propylene oxide adduct of an amine compound, an aminocarboxylic acid and a salt thereof,
1 selected from the group consisting of aminophosphonic acid and salts thereof
One or two or more nitrogen-containing compounds are contained in an amount of 0.25 to 3.50% by weight based on the total amount of the etching solution composition.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Stainless steel includes Fe--Cr alloys, Fe--Ni--Cr alloys, and Mo, Ti, A
It is an alloy to which a metal element such as 1 is added.

The stainless steel etching liquid composition according to the present invention contains ferric chloride as a main component and a mineral acid such as hydrochloric acid, sulfuric acid or nitric acid. The composition concentration of these ferric chlorides and mineral acids is not particularly limited and may be a general composition. However, when the concentration of ferric chloride is 33% by weight or less, the etching rate is promoted, but side etching does not occur. It gets worse and is not suitable for precision machining.

Further, the etching processing conditions are not particularly limited either, and the temperature usually used is 40 to 70.
° C., a sufficient range of the pressure 1.0~2.5kg / cm ^2.

Next, the nitrogen-containing compound used in the etching solution composition of the present invention will be described. As the ethylene oxide and / or propylene oxide adduct of the amine compound used in the present invention, the following general formula (1) or
Examples thereof include compounds represented by (2).

[0016]

[Chemical 6] (In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, a hydroxyalkyl group, a phenyl group or a cyclohexyl group, and x and y are the same as or different from each other in the number of 1 to 9. May be)

The above compounds include methylamine, ethylamine, propylamine, isopropylamine, butylamine, isobutylamine, sec-butylamine,
An average molecular weight of 200 to 400 obtained by adding ethylene oxide to a monoamine such as tert-butylamine, pentylamine, isopentylamine, tert-pentylamine, hexylamine, octylamine, 2-ethylhexylamine, nonylamine and decylamine.
0 polyoxyethylene alkylamine.

[0018]

Embedded image (In the formula, m and n are the numbers 0 to 9 and may be the same or different, but they are not all 0 at the same time.
Further, the addition form of ethylene oxide and propylene oxide may be block and / or random. )

Examples of such a compound include polyoxyethylene ethylenediamine, polyoxypropylene ethylenediamine and polyoxyethylene having an average molecular weight of 200 to 4000 obtained by adding ethylene oxide and / or propylene oxide to ethylenediamine in a block and / or random manner. Examples thereof include polyoxypropylene ethylenediamine.

The aminocarboxylic acid used in the present invention includes compounds represented by the following general formula (3) or (4).

Embedded image (In the formula, R ³ represents hydrogen, a phenyl group, a cyclohexyl group or a carboxylate alkyl group, M represents hydrogen or an alkali metal, and m and n are numbers from 1 to 4.)

Examples of such a compound include alkyleneaminocarboxylic acid, alkylenepolyaminocarboxylic acid, hydroxyalkyleneaminocarboxylic acid, hydroxyalkylenepolyaminocarboxylic acid, and alkali metal salts thereof.

[0022]

[Chemical 9]

Examples of such compounds include polyoxyaminocarboxylic acid, alkyleneaminocarboxylic acid, hydroxyalkyleneaminocarboxylic acid, hydroxyalkylenepolyaminocarboxylic acid, and their alkali metal salts, nitrilocarboxylic acids, alkali metal salts thereof, and the like. Can be mentioned.

The aminophosphonic acid has the following general formula:

[Chemical 10] [In the formula, R ⁶ represents hydrogen, a hydroxyl group, a cyclohexyl group, or an alkyl group having 1 to 12 carbon atoms, and n
Is a number from 1 to 3, and when n is 3, R ⁶ is a group —C.
H ₂ POM (wherein M represents hydrogen or an alkali metal)]

Examples of such a compound include alkyleneaminophosphonic acid, hydroxyalkyleneaminophosphonic acid, hydroxyalkylenepolyaminophosphonic acid, and their alkali metal salts.

The nitrogen-containing compounds of the above general formulas (1) to (5) are
It may also be used in the form of amine salts such as mono-, di-, triethanolamine salts, amine hydrochlorides.

The nitrogen-containing compound of the present invention is contained in the etching solution composition in an amount of 0.25 to 3.50% by weight, preferably 0.50 to 1.50% by weight. When the amount of the nitrogen-containing compound is less than 0.25% by weight, the finishability is poor and 3.
Even if added in an amount of more than 50% by weight, no further improvement in finish is observed and it is economically inappropriate.

The etching solution composition of the present invention can be used at a temperature of 40 to 70 ° C. after laminating or coating a photoresist after polishing and degreasing stainless steel, for example. Since the etching liquid composition of the present invention is characterized by low foaming property, it is suitable for processing by spraying, but it is also possible to add an ethoxylated secondary alcohol nonionic surfactant as a defoaming agent. Is.

Further, the etching solution composition of the present invention can be preferably used for etching stainless steel by using, for example, the etching method disclosed in JP-A-6-73563. The method can be performed by using, for example, the etching apparatus shown in FIG. 1, and the apparatus has the following configuration and operates. That is, the etching solution in the etching tank (1) is the etching solution feed pipe (9).
Through the etching solution feed pump (5) to the redox potential, hydrogen chloride concentration and specific gravity detection section (2). The overflowed etching solution is returned to the etching tank (1) through the etching solution return pipe (10) to circulate the etching solution. The circulation of the etching solution is always performed, whereby the redox potential, the hydrogen chloride concentration and the specific gravity are constantly measured.

When the measurement result of the oxidation-reduction potential of the etching solution becomes less than the set value, the control signal wiring (A) relating to the oxidation-reduction potential is used to operate the ferric chloride aqueous solution feed pump (6) to Ferric chloride aqueous solution-hydrogen chloride aqueous solution mixed solution from ferric chloride aqueous solution-hydrogen chloride aqueous solution mixed storage tank (3) through ferric chloride aqueous solution supply pipe (14)
Supply to (1). Similarly, chlorate solution feed pump (7)
To operate the chlorate solution from the chlorate solution storage tank (4) through the chlorate solution supply pipe (13) to the etching tank (1)
Supply to. If the measured value of redox potential exceeds the set value, and if the measured value of redox potential exceeds the set value,
By using the control signal wiring (A) relating to the redox potential, stopping each pump, and stopping the supply of each aqueous solution, the redox potential of the etching solution can be constantly maintained within a certain range.

When the measurement result of the hydrogen chloride concentration of the etching solution becomes less than the set value, the control signal wiring (B) relating to the hydrogen chloride concentration is used to feed the ferric chloride aqueous solution feed pump.
(6) is operated, and the ferric chloride aqueous solution-hydrogen chloride aqueous solution mixed solution from the ferric chloride aqueous solution-hydrogen chloride aqueous solution mixed storage tank (3) is passed through the ferric chloride supply pipe (12) to the etching tank.
Supply to (1). When the measured hydrogen chloride concentration exceeds the set value, use the signal control wiring (B) related to the hydrogen chloride concentration, stop each pump, and stop the supply of each aqueous solution to stop the hydrogen chloride concentration of the etching solution. Can always be kept within a certain range.

Further, when the measurement result of the specific gravity exceeds the set value, the control signal wiring (C) related to the specific gravity is used, the water supply pipe solenoid valve (8) is opened, and the etching tank (1) is passed through the water supply pipe. Supply water to. If the measurement result of the specific gravity is less than the set value, use the control signal wiring (C) related to the specific gravity, close the water supply pipe solenoid valve (8), and stop the water supply to stop the specific gravity of the etching solution. Can always be kept within a certain range.

The etching solution in the etching tank (1) increased by the supply of each aqueous solution and water is discharged from the etching tank (1) due to overflow.

When the etching liquid composition of the present invention is used in the etching apparatus having the above-mentioned structure, the regenerating liquid is appropriately replenished and kept within the initial concentration range to improve the finish of stainless steel. Excellent precision processing can be continued for a long time.

[0035]

【Example】

Example 1, Comparative Examples 1 to 3 Width 30 mm x Length 50 mm x Thickness 1 mm Stainless Steel
A test piece was produced by polishing and degreasing (Fe-Ni-Cr alloy: SUS304). As an etching solution composition, a 45 ° Baume ferric chloride aqueous solution was used, and after bathing various nitrogen-containing compounds (additives) at the concentrations shown in Table 1, the temperature was 50 ° C and the spray pressure (up and down) 2. The test piece was etched for 10 minutes under the condition of 0 kg / cm ² .

As a result, the following items were evaluated for performance,
The results are shown in Table 1. Occurrence of smut: After etching, washing with water, and drying, the appearance was visually evaluated and judged as follows. ○ No smut deposition △ Slight smut deposition × discoloration due to smut Surface roughness: needle type manufactured by Kosaka Laboratory (SE-30D)
The average roughness Ra (μm) was displayed by using a fine shape measuring instrument according to the above. Etching rate: The test piece was half-etched, measured with a digital micrometer, and calculated as the etching rate per minute (μm / min). Surface condition: evaluated visually.

[0037]

[Table 1]

The additives in Table 1 are as follows: a: Propylamine ethylene oxide 2 mol adduct b: Cyclohexylamine ethylene oxide 2.2 mol adduct c: Ethylenediamine 2 ethylene oxide 2 mol propylene oxide 2 mol adduct. Substance d: cyclohexane-1,2-diaminetetraacetic acid e: pentasodium salt of diethylenetriaminepentaacetic acid f: ethylene glycol diethyl ether diaminetetraacetic acid g: 1-aminopropane-1,1-diphosphonic acid h: 1-aminopropane- Ethanolamine salt of 1,1-diphosphonic acid 1: No additive 2: Polyethylene glycol (Molecular weight 400: PEG4
00) 3: Nonionic surfactant "Adecatol SO"

Examples 2 to 9 and Comparative Examples 4 to 6 Stainless steel plates SUS304 (Fe-Ni-Cr alloy) and SUS43 having a width of 30 mm, a length of 50 mm and a thickness of 1 mm.
Two types of test pieces were prepared by polishing and degreasing 0 (Fe-Cr alloy). A bath was prepared based on the composition table of Table 2 as an etching solution composition, and then the same test as in Example 1 was performed. The results are shown in Table 3.

[0040]

[Table 2]

In Table 2, nitrogen-containing compound A is diethylenetriaminepentaacetic acid, and nitrogen-containing compound B is ethylenediamine 2 mol propylene oxide 2 mol adduct of ethylenediamine.

[0042]

[Table 3]

From the results shown in Tables 1 and 3, the etching liquid composition of the present invention was compared with the etching liquid composition of the comparative example.
It is clear that the surface is excellent in glossiness and smoothness, and the anti-smut effect is high, thereby improving the etching rate.

Examples 10 to 20 and Comparative Examples 7 to 9 SUS304 and SUS631 (Fe-
(Ni-Cr-Al alloy) steel material, a circular ring pattern having a line and space width of 250 [mu] m was prepared, and based on the composition and conditions in Table 4, the same conditions as in Examples 1 to 8 were used.
Etching was carried out at a temperature of 50 ° C. and a spray pressure of 2.0 kg / cm ² for evaluation. In addition to the items of Examples 1 to 8 as evaluation items, side etching and pitting corrosion were also evaluated, and the test results are shown in Table 5. Side etch: The side etch amount (μm) with respect to the progress width of the resist of 30 μm was measured with a dynascope. Pitting corrosion: The inner wall surface of the etching was photographed with an electron microscope, the interface was determined, and displayed as the pitting depth Rt (Max). ○ Rt ≦ 3 μm Δ 3 μm <Rt <5 μm × 5 μm ≦ Rt

[0045]

[Table 4]

In Table 4, nitrogen-containing compound A is diethylenetriaminepentaacetic acid, and nitrogen-containing compound B is ethylenediamine 2 mol ethylene oxide 2 mol propylene oxide 2 mol adduct.

[0047]

[Table 5]

From the results shown in Table 5, the amount of stainless steel dissolved in the etching solution composition of the present invention is 40 g / l, while the amount of stainless steel dissolved in the comparative example, which is considered to be the normal liquid life, is 20 g / l. It can be seen that even when the liter is reached, the etching rate is improved almost twice, and the finish properties (glossiness, surface smoothness, pitting corrosion, side etching) are excellent. An etch factor of 4.0 or more was obtained at this time.

That is, in the etching solution composition of the present invention, a smooth and glossy finished surface is obtained even when the amount of stainless steel dissolved is 40 g / liter, and side etching and pitting corrosion are excellent. It turns out that precise processing is possible.

Example 21 SUS304 steel material was continuously etched using the etching apparatus shown in FIG. 1 and the stability of the liquid was evaluated. As liquid management conditions, the FeCl ₃ concentration is 36% by weight,
The concentration of FeCl ₂ was 0.3 mol / liter, the concentration of free hydrochloric acid was 0.15% by weight, the concentration of dissolved stainless steel was 40 g / liter, and the total concentration of nitrogen compounds was 1.1%. Using a spray-type etching tank (effective etching distance of 4 m, liquid holding amount of 3100 liters) and a liquid management device that detects and controls redox potential, hydrogen chloride concentration, and specific gravity, the equipment shown in Fig. 1 is used for etching. The control set values were as follows. Redox potential: 600 mV Potential related to hydrogen chloride concentration: 470 mV (Measure and control potential generated from pH electrode with voltmeter) Specific gravity: 1.480 49 degrees Baume ferric chloride aqueous solution, 35% hydrochloric acid aqueous solution as drug The ferric chloride: hydrogen chloride molar ratio is 15.8:
A mixture of ethylene diamine 2 mol polypropylene oxide 2 mol adduct 0.7% by weight and 1-aminopropane-1-phosphonic acid 0.4% by weight. (Solution A),
A 38% sodium chlorate aqueous solution (this is referred to as solution B) is used, and A
Solution B and solution B are supplied so that the molar ratio of ferric chloride: hydrogen chloride: sodium chlorate is 15.8: 8: 1, and solution A is supplied at the same ratio as above according to the detection result of hydrogen chloride concentration. Then
Water was supplied according to the detection result of specific gravity. Etching temperature 5
0 ° C., spray pressure 2.0 kg / cm ² , stainless steel SUS304 material (300 mm × 400 mm, thickness 0.1)
(5 mm) multi-sided printer parts etc. are etched to obtain 500 sheets, 1200 sheets, 2500 sheets, 3500 sheets,
The etching rate was measured by half-processing every 4200 sheets and 4800 sheets. The number of processed products and etching rate (one side)
The relationship is shown in FIG.

From the result of automatic replenishment of the liquid by the continuous processing shown in FIG. 2, the etching rate is stable with respect to the production amount,
It can be seen that the etching solution composition of the present invention is easy to manage and is effective for continuous production.

[0052]

As described above, the effects of the present invention are
Finishability in etching stainless steel
It is intended to provide an etching solution composition having improved (glossiness, surface smoothness, pitting corrosion, side etching) and solution life.

[Brief description of the drawings]

FIG. 1 is a schematic view of an etching apparatus that can suitably use the etching liquid composition of the present invention.

FIG. 2 is a graph showing the relationship between the number of processed wafers and the etching rate (half-processed surface) in Example 21.

[Explanation of symbols]

 1 etching tank 2 redox potential, hydrogen chloride concentration, specific gravity detection unit 3 ferric chloride aqueous solution-hydrogen chloride aqueous solution mixed storage tank 4 chlorate aqueous solution storage tank 5 etching liquid feed pump 6 ferric chloride aqueous solution feed pump 7 chloric acid Salt aqueous solution feed pump 8 Water supply pipe Solenoid valve 9 Etching liquid feed pipe 10 Etching liquid return pipe 11 Water supply pipe 12 Ferric chloride aqueous solution supply pipe 13 Chlorate aqueous solution supply pipe 14 Control unit for each solution and water supply A Oxidation Control signal wiring related to reduction potential B Control signal wiring related to hydrogen chloride concentration C Control signal wiring related to specific gravity

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kimihiko Ikeda 7-35, Higashiohisa, Arakawa-ku, Tokyo Within Asahi Denka Co., Ltd. (72) Ryoji Kabeya 7-2, Higashiohisa, Arakawa-ku, Tokyo No. 35 In Asahi Denka Kogyo Co., Ltd. (72) Inventor Nobuyuki Shimamura 7-2-35 Higashiohisa, Arakawa-ku, Tokyo Within Asahi Denka Kogyo Co., Ltd.

Claims (5)

[Claims] 1. An etchant containing ferric chloride as a main component, an ethylene oxide and / or propylene oxide adduct of an amine compound, an aminocarboxylic acid and a salt thereof,
1 selected from the group consisting of aminophosphonic acid and salts thereof
One or two or more nitrogen-containing compounds are contained in an amount of 0.25 to 3.50% by weight based on the total amount of the etching solution composition. 2. The etching solution composition for stainless steel according to claim 1, wherein the ethylene oxide adduct of the amine compound is one or more compounds represented by the following general formula (1): ] (In the formula, R ¹ represents an alkyl group having 1 to 12 carbon atoms, a hydroxyalkyl group, a phenyl group or a cyclohexyl group, and x and y are the same as or different from each other in the number of 1 to 9. May be) 3. Ethylene oxide and / or amine compound
Alternatively, the propylene oxide adduct is represented by the following general formula (2)
The etching solution composition for stainless steel according to claim 1, which is one or more compounds represented by: (In the formula, m and n are the numbers 0 to 9 and may be the same or different, but they are not all 0 at the same time.
Further, the addition form of ethylene oxide and propylene oxide may be block and / or random. ) 4. The stainless steel etching liquid composition according to claim 1, wherein the aminocarboxylic acid and its salt are one or more compounds represented by the following general formula (3) or (4). : [Chemical 3] (In the formula, R ³ represents hydrogen, a phenyl group, a cyclohexyl group, or a carboxylate alkyl group, M represents hydrogen, an alkali metal, and m and n are numbers from 1 to 4); ] 5. Aminophosphonic acid and salts thereof have the general formula
The etching solution composition for stainless steel according to claim 1, which is one or more compounds represented by (5): [In the formula, R ⁶ represents hydrogen, a hydroxyl group, a cyclohexyl group, or an alkyl group having 1 to 12 carbon atoms, and n
Is a number from 1 to 3, and when n is 3, R ⁶ is a group —C.
H ₂ POM (wherein M represents hydrogen or an alkali metal)]