JP2002082451A - Multistage etching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multistage etching method which is excellent ink the selectivity of an etching direction, is capable of anisotropically etching film in the thickness direction of a film to be etched and etches the film uniformly in well-regulated shape without variation. SOLUTION: This multistage etching method consists of etching the resin film by using an etchant which contains at least one of an alkaline metal compound and an aliphatic amine compound in wet etching the resin film in multiple stages. The content concentration of the alkaline metal compound in this etchant has a concentration gradient which is higher toward the rear stages and the content concentration of the aliphatic amine compound has a concentration gradient which is lower toward the rear stages.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching solution used for wet etching of a resin film used for a wiring board and an etching method using the etching solution.

[0002]

2. Description of the Related Art Conventionally, as a method for etching a resin such as polyimide, a method for wet etching using a solution containing hydrazine as a main component has been disclosed.
(JP-A-5-202206) and another etching method using potassium hydroxide is disclosed (JP-A-5-202206).
-301981).

[0003] However, it is difficult to provide selectivity in the direction of etching by the usual wet etching method, and the lateral direction and the thickness direction of the film to be etched are etched to the same extent, and the etching is performed. As the film becomes thicker, it becomes more difficult to etch a fine pattern. For example, when a film having a thickness of 50 μm is to be etched, a normal wet etching method is used.
It was impossible to drill holes having a diameter of 0 μmφ or less.
In addition, the finer the pattern, the longer the time required for the etching, and there is a problem that the variation in the etching is increased.

In any case, there is no example in which a method of performing etching in multiple stages has been adopted in wet etching of a resin film used for a wiring board.

[0005]

According to the present invention, in such a multi-step etching, the selectivity of the etching direction is excellent, and the etching can be performed anisotropically in the thickness direction of the film to be etched. Evenly and uniformly,
Further, it is an object of the present invention to provide a multi-step etching method for etching in a well-defined shape.

[0006]

The present invention employs the following means in order to solve the above-mentioned problems. That is, the multi-stage etching method of the present invention is an etching solution containing at least one of an alkali metal compound and an aliphatic amine compound when wet-etching a resin film in multiple stages. The content concentration of the alkali metal compound has a concentration gradient that is higher toward the later stage, and the content concentration of the aliphatic amine compound uses an etching solution that has a concentration gradient that is lower toward the later stage. And etching.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made to solve the above-mentioned problem, that is, it has excellent selectivity in an etching direction, can perform anisotropic etching with respect to a thickness direction of a film to be etched, and has uniformity without variation. And, a multi-step etching method for etching in a well-formed shape is studied diligently, using an etchant containing an alkali metal compound or an aliphatic amine compound or both,
It is a method of etching in multiple stages, and furthermore, when the alkali metal compound is etched with an etching solution having a concentration gradient which becomes higher toward the latter stage and the aliphatic amine compound is reversed in the concentration gradient, It was determined that the issues could be solved all at once.

The etching solution used for the multi-stage etching of the present invention uses an etching solution containing one or both of an alkali metal compound and an amine compound. To describe this etching method more specifically, the concentration of the alkali metal compound in the etching solution used in the n-th stage is higher than the concentration of the alkali metal compound in the etching solution used in the (n + 1) -th stage, or n The aliphatic amine compound content in the etching solution used in the (n + 1) -th stage is lower than the aliphatic amine compound content concentration in the etching solution used in the (n + 1) -th stage, or the alkali in the etching solution used in the n-th stage The concentration of the metal compound is higher than the concentration of the alkali metal compound in the etching solution used in the (n + 1) th stage, and the concentration of the aliphatic amine compound in the etching solution used in the nth stage is the (n + 1) th stage. Use a characteristic etchant that is lower than the aliphatic amine compound content in the etchant used for Is to etch in multiple stages Te (where n is an integer of 1 or more).

The etching solution is preferably uniform, but may be non-uniform in some cases. Alkali metal compounds include, but are not limited to, potassium hydroxide, lithium hydroxide, sodium hydroxide, and the like. Examples of the aliphatic amine compound include propylamine, hexylamine, ethylenediamine, triethylenediamine, hexamethylenediamine, propylenediamine, piperazine, piperidine, ethanolamine, n-propanolamine, isopropanolamine, n-butanolamine, and diethanolamine. But not limited to these. In addition to these, for example, aromatic alcohols, aliphatic alcohols, urea, ketones, ethers, water, electron donors and the like can be added. Specifically, phenol, benzyl alcohol, hydroquinone, methanol, ethanol, propanol, butanol, hexanol, ethylene glycol, propylene glycol, diethylene glycol,
Triethylene glycol, tetraethylene glycol,
Dipropylene glycol, tripropylene glycol,
Examples include, but are not limited to, tetrapropylene glycol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dioxane, diethyl ether, and the like. Specific combinations include, for example, the following, but are not limited thereto. (1) alkali metal compound / water (eg, potassium hydroxide / water, sodium hydroxide / water), (2) alkali metal compound / alcohol (eg, potassium hydroxide / methanol, sodium hydroxide / methanol, potassium hydroxide /
Ethanol, sodium hydroxide / ethanol, potassium hydroxide / ethylene glycol, sodium hydroxide / ethylene glycol), (3) aliphatic amine compounds / water (eg, ethanolamine / water, ethylenediamine / water, diethanolamine / water), (4) ) Aliphatic amine compounds /
Alcohols (eg, ethanolamine / methanol, ethanolamine / ethanol, ethanolamine / ethylene glycol, ethanolamine / glycerin, ethylenediamine / methanol, ethylenediamine / ethanol, ethylenediamine / ethyleneglycol, ethylenediamine / glycerin, diethanolamine / methanol, diethanolamine / ethanol, diethanolamine / Ethylene glycol, diethanolamine / glycerin), (5) aliphatic amine compounds / ketones (eg, ethanolamine / acetone, ethanolamine /
Methyl ethyl ketone, ethanolamine / methyl isobutyl ketone, ethylenediamine / acetone, ethylenediamine / methylethylketone, ethylenediamine / methylisobutylketone, diethanolamine / acetone,
(6) aliphatic amine compounds / alkali metal compounds / alcohols (eg, ethylenediamine / potassium hydroxide / ethanol, ethanolamine / potassium hydroxide / ethylene glycol,
Ethylenediamine / potassium hydroxide / ethylene glycol, ethanolamine / potassium hydroxide / ethanol,
(Ethylenediamine / sodium hydroxide / ethanol, ethanolamine / sodium hydroxide / ethylene glycol, ethylenediamine / sodium hydroxide / ethylene glycol, ethanolamine / sodium hydroxide / ethanol), (7) aliphatic amine compound / alkali metal compound / water (For example, ethylenediamine / potassium hydroxide /
Water, ethanolamine / potassium hydroxide / water, ethylenediamine / sodium hydroxide / water, ethanolamine /
Sodium hydroxide / water), (8) aliphatic amine compound /
Alkali metal compound / alcohol / water (for example, ethylenediamine / potassium hydroxide / ethylene glycol / water,
Ethanolamine / potassium hydroxide / ethylene glycol / water, ethylenediamine / sodium hydroxide / ethylene glycol / water, ethanolamine / sodium hydroxide / ethylene glycol / water, ethylenediamine / potassium hydroxide / glycerin / water, ethanolamine / hydroxide Potassium / glycerin / water, ethylenediamine / sodium hydroxide / glycerin / water, ethanolamine / sodium hydroxide / glycerin / water).

When performing multi-stage etching using the above-described etching solution, it is not particularly limited at which stage of the m-stage etching the etching with the above-mentioned concentration difference is performed, but usually, the etching is performed from an early stage. It is preferable to carry out the treatment continuously in as many stages as possible. (Where m is an integer of 2 or more, n is an integer of 1 or more, and m ≧ n + 1).
It is preferable to carry out the first and second stages, and then to carry out the third and subsequent stages. Since the difference in concentration differs depending on the type of the resin film to be etched, it cannot be unconditionally determined.
1) The difference in the concentration of the etching solution in the first stage is 1% or more, and more preferably, the difference in the concentration is 2% or more. In particular, in the case of an alkali metal compound, the content concentration difference is 5
% Is preferable. In this case, it is not necessary to make the density difference constant, and it is preferable to appropriately change the density difference as needed. However, the alkali metal compound is effective for decomposing the resin film, but if the concentration is extremely high, it will be etched more than necessary. On the contrary, if the concentration is extremely low, the decomposition efficiency is lowered and it is not practical. The content concentration is in the range of 1 to 99%, preferably 5 to 95%. In particular, in the case of an alkali metal compound, if the concentration is extremely high, solids may precipitate and the concentration may change. Therefore, the content is selected in the range of 5 to 85%. By using etching solutions with different concentrations, it is possible to first etch a considerable part with a high-concentration etching solution, and then finish with a low-concentration etching solution, and anisotropically in the thickness direction of the resin film Etching can be performed, and a uniform and uniform shape can be etched. Although a high-concentration etchant is more excellent in etching efficiency, it is difficult to control the etching rate, and it is difficult to adjust the shape using only a single etchant. Although the etching rate is lower, the etching rate is lower, but it has the advantage that the entirety can be uniformly etched. Therefore, efficient and uniform etching can be realized by selectively using the high-concentration etching solution in order from the low-concentration etching solution. As a specific example, it is effective to first perform etching with an etching solution having a content concentration of 60%, and then perform etching with an etching solution having a content concentration of 40% and an etching solution having a content concentration of 30% in that order.

An aliphatic amine compound is effective for dissolving a decomposition product of a resin film. However, if the concentration is too high, etching of the resin film in a horizontal direction (perpendicular to the thickness direction) is selective. If the content is extremely low, the solubility of the decomposition product of the resin film deteriorates. Therefore, the content concentration is also 1 to 99%, preferably 5 to 95%. First, the etching is progressed anisotropically in the thickness direction of the resin film with a low-concentration etching solution, and then the shape can be adjusted by using a high-concentration etching solution. Efficient and uniform etching can be realized by selectively using a high-concentration etching solution. As a specific example, it is effective to first perform etching with an etching solution having a content concentration of 5%, and then perform etching with an etching solution having a content concentration of 10% and an etching solution having a content concentration of 20%.

Further, a method in which an alkali metal compound and an aliphatic amine compound are used in combination is also effective. When both are used, a synergistic effect of each function can be expected.

The temperature of the etching solution greatly depends on the properties of the resin film to be etched and also on the composition of the etching solution, but is preferably 10 to 90 ° C., more preferably 30 to 80 ° C. If the temperature is too high, the composition of the etching solution changes during the etching. Conversely, if the temperature is too low, the efficiency of the etching decreases, so that the above range is preferable.

Examples of the wet etching method include a method of dipping a film to be etched in an etchant, a method of spraying an etchant on the film to be etched, and the like. In the case of spraying an etching solution, a method is generally used in which a spray nozzle is attached to the tip of a blowout port and blows out with pressure.

Regarding the shape of the spray nozzle,
Although there is no particular limitation, for example, mini mist, round mist, air jet nozzle, descaling nozzle, QC nozzle, flat spray nozzle, wide flat nozzle, oblong nozzle, oblique flat nozzle, side spray of Kyoritsu Gosei Seisakusho Co., Ltd. Nozzle, full cone nozzle, square nozzle, elliptical nozzle, spiral nozzle, hollow cone nozzle,
A cleaning nozzle, a needle jet nozzle, or the like can be used, but is not limited thereto. Such nozzles may be used alone or in combination, or different types of nozzles may be used in combination.

The pressure to be blown out varies greatly depending on the type and thickness of the film to be etched.
It is conceivable that the gas is ejected at a pressure of 000 to 10,000,000 Pa. The jetting direction is usually the thickness direction of the film to be etched, but in some cases, the jetting may be from the lateral direction or the oblique direction of the etching film.

Also, a method of applying ultrasonic waves during wet etching is effective. A well-known vibrator is generally used for generating the ultrasonic waves. The frequency of these vibrators is not particularly limited, but is preferably 10 to 1000 kHz, more preferably 20 to 600 kHz. These vibrators may be used alone or in combination. The direction of the ultrasonic wave is usually the thickness direction of the film to be etched, but in some cases, the ultrasonic wave may be applied from the lateral direction or the oblique direction of the etched film.

Further, a method of irradiating ultraviolet rays during wet etching is also effective. The wavelength range of the ultraviolet light to be irradiated is not particularly limited, but is preferably 200 to 500.
nm. In this case, the entire wavelength of the light source may be irradiated, or only a specific wavelength of ultraviolet light may be irradiated using a filter or the like. For example, i-line (365 nm) and g-line (4
It is also possible to irradiate only 36 nm) or conversely, to irradiate ultraviolet rays cut off only these wavelengths. Furthermore,
The wavelength of the ultraviolet light may be appropriately changed during the etching.

As the lamp for irradiating the ultraviolet rays, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a DEEP UV lamp, a flash UV lamp, a short arc metal halide lamp and the like can be used. It is not limited to. The amount of ultraviolet light depends on the type and thickness of the film to be etched, but is preferably such that the irradiation time is at most 60 minutes or less in consideration of the working time. For example, 0.01-10W
/ Cm2 range is conceivable, but not limited thereto. The irradiation direction of the ultraviolet ray is usually the thickness direction of the film to be etched, but in some cases, the irradiation may be performed from the lateral direction or the oblique direction of the etching film, and the irradiation may be performed from all directions.

Next, as the material of the resin film used in the present invention, polyimide (for example, “Kapton” manufactured by Toray Dupont Co., Ltd., “Upilex” manufactured by Ube Industries, Ltd., “Kapton Chemical Industry Co., Ltd.”) Apical ”), polyamide (eg,“ Mictron ”manufactured by Toray Industries, Inc.), PPS
(Polyphenylene sulfide), PET (polyethylene terephthalate, for example, "Lumirror" manufactured by Toray Industries, Inc.), liquid crystal polymer (for example, "Siveras" manufactured by Toray Industries, Inc., "Vectra" manufactured by Polyplastics, Nippon Petrochemical ( And the like, but are not limited thereto. The above resin may be used alone, or may be a blend of two or more kinds or a lamination. Further, various additives may be added to the resin film. Examples of the additive include, but are not limited to, a filler such as a flame retardant, glass cloth, and the like. Among these, a resin film mainly composed of polyimide, polyamide or liquid crystal polymer is particularly preferable. The resin film may be cut into an appropriate size or may be a strip. Further, the support may be attached to another material or may be adhered. In this case, a conductive material such as a metal, a resin, glass, wood, paper, a silicon wafer, or the like can be used as the support. Among these supports, a conductive material such as a metal is preferable, and such a conductive material can be used as it is for a conductive layer in plating.

[0021] The thickness of the resin film is not particularly limited, and can be selected to be suitable for the intended use, but is preferably 5 to 500 µm, more preferably 10 to 100 µm.
μm. If the thickness is too small, handling becomes difficult, and if the thickness is too large, it becomes difficult to form fine holes accordingly, so the above range is preferable.

Next, a series of wet etching procedures using the etching solution for multi-stage etching according to the present invention will be described, but the present invention is not limited to this procedure.

First, chromium is sputtered on both sides of the resin film, and then a copper layer is formed on both sides of the resin film by electrolytic plating. A photoresist is applied to the formed copper layers on both sides, and one of the photoresists is exposed and developed in accordance with a fine hole forming pattern. At this time, the photoresist on the side opposite to the pattern is left as it is. Next, the copper exposed according to the pattern of the photoresist is removed by etching. After the copper etching, the photoresist on both sides is removed. Using the material prepared in this manner, etching is first performed with a first-stage etching solution (an etching solution having a high alkali metal content or an etching solution having a low aliphatic amine compound content) in accordance with a copper pattern. Then, etching is performed with a second-stage etching solution (an etching solution having a low alkali metal content or an etching solution having a high aliphatic amine compound content). In the case of three or more steps of etching, the etching is further performed with a corresponding etching solution.

The resin film treated with the etching solution of the present invention has through holes according to the etching pattern. By embedding a metal (such as copper or aluminum) for conduction in the through-hole, conduction on both sides of the resin film can be achieved. Further, by providing wiring on both surfaces of the resin film, a wiring board of two-layer wiring in which both surfaces are electrically connected can be obtained.

According to the present invention, since the hole for conducting can be finely formed in a good shape, the area that can be used for wiring increases accordingly, and as a result, a high-density wiring board can be formed. High-density wiring boards can be used for a wide range of applications from large substrates such as personal computer motherboards to small substrates such as CSP (chip scale package) interposers.

[0026]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 and Comparative Example 1 A 50 μm thick resin film of polyimide film “Kapton EN”, “Upilex S”, “Apical NPI”, polyamide film “Miktron”, liquid crystal polymer film “Vectra CX” was sputtered with chromium and copper. A 5 μm thick copper foil was formed on both sides by sputtering and plating.

A positive type photoresist "AZ P4000" manufactured by Hoechst Co., Ltd. was applied to both surfaces of the copper foil with a spin coater and dried on a hot plate at 100 ° C. for 3 minutes. Next, using a mask containing circular patterns of 50 and 100 μmφ, one side was 300 m with a g-line stepper.
Exposure to J / cm 2 was carried out, and AZ 400K developer was developed for 3 minutes using a developing solution diluted 5 times with water to form circular patterns of 50 and 100 μmφ suitable for the mask.

Using the patterned photoresist as a copper etching mask and an aqueous solution of iron chloride at 40 ° C. as an etchant, a pressure of 196 was applied from a full cone nozzle (model number 1 / 4KSFHS0665) manufactured by Kyoritsu Alloys Manufacturing Co., Ltd.
The copper was patterned by etching for 5 minutes while spraying at 133 Pa.

After the etching of the copper is completed, the photoresist is removed. This time, using the patterned copper as a mask, an etching solution (A) composed of 50 g of potassium hydroxide and 50 g of water is used at 70 ° C. for 10 minutes. 38 kHz
While irradiating the ultrasonic waves. Next, an etching solution (B) composed of 30 g of sodium hydroxide and 70 g of water was immersed at 70 ° C. for 10 minutes, and ultraviolet rays were irradiated with copper at 10 mW / cm ² using a high-pressure mercury lamp manufactured by Ushio Inc. Etching was performed while irradiating the mask surface.

The results are as shown in Table 1. The anisotropically clean shape was uniformly etched.

The taper angle shown in Table 1 is a measure of anisotropy, and the smaller the value of the taper angle, the more anisotropically the resin film can be etched in the thickness direction. When etching can be performed completely in the thickness direction, the taper angle is 0.
Degree. The taper angle is [taper angle] = tan
^-1 ([difference between upper and lower holes] / 2 / [resin film thickness]).

Comparative Example 1 The procedure of Example 1 was repeated except that only the etching solution (A) was used without using the etching solution (B) (that is, the etching solution (A) was used instead of the etching solution (B)). Etching was performed in the same manner as in Example 1.

The results are as shown in Table 1 and were not anisotropically etched, were non-uniform, and had poor shape.

Comparative Example 2 The procedure of Example 1 was repeated, except that only the etchant (B) was used without using the etchant (A) (ie, the etchant (B) was used instead of the etchant (A)). Etching was performed in the same manner as in Example 1.

The results are as shown in Table 1. The film was not etched anisotropically, was not uniform, and had a poor shape.

Example 2 In Example 1, 20 g of potassium hydroxide, 30 g of water and 10 g of ethylenediamine were used in place of the etching solution (B).
g, and etching was performed in the same manner as in Example 1 except that an etching solution (C) composed of 40 g of ethylene glycol was used.

The results are as shown in Table 1. The anisotropically clean shape was uniformly etched.

[0039]

[Table 1]

Example 3 In Example 1, 20 g of ethylenediamine, 40 g of water and ethylene glycol 4 were used instead of the etching solution (A).
0 g of an etching solution (D), and instead of the etching solution (B), 60 g of ethanolamine and 40
Etching was performed in the same manner as in Example 1 except that the etching solution (E) composed of g was used.

The results are as shown in Table 2, and it was possible to etch uniformly in an anisotropically clean shape.

COMPARATIVE EXAMPLE 3 In Example 3, except that only the etching solution (D) was used without using the etching solution (E) (that is, the etching solution (D) was used instead of the etching solution (E)), all the operations were performed. Etching was performed in the same manner as in Example 3.

The results are as shown in Table 2, which was not anisotropically etched, was non-uniform, and had a poor shape.

Comparative Example 4 In Example 3, all operations were performed except that the etching solution (E) was used without using the etching solution (D) (that is, the etching solution (E) was used instead of the etching solution (D)). Etching was performed in the same manner as in Example 3.

The results are as shown in Table 2 and were not anisotropically etched, were non-uniform, and had poor shape.

Example 4 In Example 3, 20 g of sodium hydroxide, 15 g of ethylenediamine and 35 g of water were used in place of the etching solution (D).
g, and etching was performed in the same manner as in Example 3 except that an etching solution (F) composed of 30 g of ethylene glycol was used. The results are as shown in Table 2, and the anisotropically clean shape was uniformly etched.

[0047]

[Table 2]

Example 5 Using the same resin film as in Example 1, first, a copper mask was formed in the same manner as in Example 1. After forming the copper mask, an etching solution (G) composed of 33 g of potassium hydroxide, 34 g of water, 22 g of ethylene glycol, and 11 g of ethylenediamine
Was irradiated at 10 mW / cm ² using a high-pressure mercury lamp manufactured by Ushio Inc. at a temperature of 70 ° C., and a full cone nozzle (model number 1) manufactured by Kyoritsu Alloys Manufacturing Co., Ltd.
/ 4KSFHS0665) at a pressure of 195,000 Pa for 10 minutes while spraying onto the copper mask surface.
Next, using an etching solution (H) composed of 10 g of sodium hydroxide, 35 g of water, 40 g of ethylene glycol, and 15 g of ethylenediamine at 70 ° C., immersed for 10 minutes, and irradiated a 100 kHz ultrasonic wave on the copper mask surface, and 10mW / using a high pressure mercury lamp manufactured by USHIO INC.
Etching was performed while irradiating the copper mask surface with ultraviolet rays at cm ² .

The results are as shown in Table 3, and the etching was anisotropically clean and uniform.

Example 6 In Example 1, after etching was performed using the etching solution (B), 10 g of potassium hydroxide and 90 g of water were further added.
The etching solution (I) composed of the above was used at 70 ° C. and immersed for 5 minutes to perform etching.

The results are as shown in Table 3. The etching was anisotropically clean and uniform.

Example 7 In Example 3, after performing etching using the etching solution (E), 70 g of ethanolamine and 30 parts of water were further added.
g at 70 ° C. using an etching solution (J) composed of
It was immersed for a minute and etched.

The results are as shown in Table 3, and the etching was uniform and anisotropically clean.

Example 8 In Example 5, after performing etching using the etching solution (H), 5 g of sodium hydroxide and 30 g of water were added.
g, ethylene glycol 45 g, ethylene diamine 20
g at 70 ° C. using an etching solution (K) composed of
It was immersed for a minute and etched.

The results are as shown in Table 3. The etching was anisotropically clean and uniform.

[0056]

[Table 3]

Example 9 In Example 6, after etching was performed using the etching solution (I), an etching solution (L) composed of 5 g of potassium hydroxide and 95 g of water was further used at 70 ° C. for 5 minutes. It was immersed and etched.

The results are as shown in Table 4, and the etching was uniform and anisotropically clean.

Example 10 In Example 7, after etching was performed using an etching solution (J), 80 g of ethanolamine and 20 g of water were further added.
g at 70 ° C. using an etching solution (M) composed of
It was immersed for a minute and etched.

The results are as shown in Table 4, and the etching was uniform and anisotropically clean.

Example 11 In Example 8, after etching was performed using the etching solution (K), 3 g of sodium hydroxide and 30 g of water were further added.
g, ethylene glycol 47 g, ethylene diamine 20
g at 70 ° C. using an etching solution (N) composed of
It was immersed for a minute and etched.

The results are as shown in Table 4. The etching was anisotropically clean and uniform.

[0063]

[Table 4]

Example 12 In Example 1, an etching solution (O) composed of 45 g of potassium hydroxide, 5 g of urea and 50 g of water was used instead of the etching solution (A), and water was used instead of the etching solution (B). Example 1 except that an etching solution (P) composed of 25 g of sodium oxide, 5 g of urea, and 70 g of water was used.
Etching was performed in the same manner as described above.

The results are as shown in Table 5, and the etching was uniform and anisotropically clean.

Example 13 In Example 3, an etching solution (Q) composed of 20 g of ethylenediamine, 40 g of water, 5 g of urea and 35 g of ethylene glycol was used in place of the etching solution (D). Ethanolamine 6
Etching was performed in the same manner as in Example 3 except that an etching solution (R) composed of 0 g, 5 g of urea, and 35 g of water was used.

The results are as shown in Table 5. The etching was anisotropically clean and uniform.

Example 14 In Example 5, 33 g of potassium hydroxide, 33 g of water and 20 g of ethylene glycol were used instead of the etching solution (G).
g, urea 3 g, and ethylene diamine 11 g, and an etching solution (T) composed of sodium hydroxide 10 g, water 34 g, ethylene glycol 38 g, and ethylene diamine 15 g instead of the etching solution (H). Etching was carried out in the same manner as in Example 5 except for using.

The results are as shown in Table 5, and it was possible to etch uniformly in an anisotropically clean shape.

[0070]

[Table 5]

[0071]

According to the present invention, the wiring substrate can be etched anisotropically, uniformly, and in a uniform shape. Therefore, many fine holes can be formed in a desired size.

Claims (5)

[Claims] An etching solution containing an alkali metal compound when the resin film is wet-etched in multiple stages, and the concentration of the alkali metal compound in the etching solution is higher toward a later stage. A multi-stage etching method characterized by performing etching using an etching solution having a concentration gradient. 2. An etching solution containing an aliphatic amine compound when a resin film is wet-etched in multiple stages, wherein the concentration of the aliphatic amine compound in the etching solution is lower toward a later stage. A multi-stage etching method characterized by performing etching using an etching solution having a concentration gradient. 3. An etching solution containing an alkali metal compound and an aliphatic amine compound when the resin film is wet-etched in multiple stages, wherein the concentration of the alkali metal compound in the etching solution and the content of the aliphatic metal compound are adjusted. A multi-stage etching method characterized in that an amine compound-containing concentration is etched toward a later stage using an etching solution having a higher concentration gradient in the former and a lower concentration gradient in the latter. 4. An etching solution for wet-etching a resin film in multiple stages, an etching solution containing an alkali metal compound, wherein the concentration of the alkali metal compound in the etching solution used in the first stage is two stages. An etching solution for multi-stage etching characterized by having a higher concentration of an alkali metal compound in an etching solution used for eyes. 5. An etching solution for wet-etching a resin film in multiple stages, an etching solution containing an aliphatic amine compound, wherein the concentration of the aliphatic amine compound content in the etching solution used in the first stage is An etching solution for multi-stage etching, wherein the concentration is lower than the aliphatic amine compound content in the etching solution used in the second stage.