JPH0517604A - Etching solution for polyimide resin - Google Patents

Abstract

PURPOSE:To obtain an etching solution with which a cured polyimide resin can be etched safely at a high rate with easiness of handling by mixing water with an aprotic organic solvent compatible with water, a protonic organic solvent compatible with water, and a basic compound. CONSTITUTION:The title solution is obtained by mixing the following four essential ingredients: water, an aprotic organic solvent compatible with water (e.g. methyl ethyl ketone), a protonic organic solvent compatible with water (e.g. methanol), and a basic compound (e.g. sodium hydroxide). By the use of this etching solution which can be handled safely, a completely cured polyimide resin can be etched at an extremely high rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching solution for a polyimide resin, and more specifically, water, an aprotic organic solvent compatible with water, and a protic organic solvent compatible with water, Further, the present invention relates to an etching solution of a polyimide resin containing four components consisting of a basic compound as essential components.

[0002]

2. Description of the Related Art Polyimide resins have been used in various applications as insulating films, insulating varnishes, paints, molded products, etc. due to their excellent heat resistance, electrical characteristics, chemical resistance, etc. There have been various applications in which a part of polyimide resin is removed by etching. For example, when a polyimide resin is used for the insulating layer, it is usually necessary to form holes in the resin insulating layer by etching in order to electrically connect the upper and lower conductor layers and the external leads.

Conventionally, as an etching solution for a polyimide resin, a solution such as hydrazine or alkali has been proposed. For example, when a solution of hydrazine hydrate is used, the etching behavior of hydrazine with respect to the polyimide resin is that rapid etching is performed after an incubation period of a certain time, and hydrazine penetrates into the lower part of the etching resist film. There is a problem in that even a portion that does not require etching is melted by a rapid etching action after the etching. In order to shorten this incubation period,
For example, JP-A-63-193927 and JP-A-1-173.
621, 321682, etc., suggests the use of a mixed solution of hydrazine hydrate and ethylenediamine, but both hydrazine hydrate and ethylenediamine are highly dangerous chemicals in handling, and are extremely difficult to handle in practical use. difficult.

Further, it has been proposed to use an aqueous solution of an alkali metal hydroxide as an etching solution. Although the danger of the above chemicals can be avoided, the etching power at around room temperature is very weak and the surface of the polyimide resin is rough. It is used only for the purpose of changing. Further, even if the etching power is increased by increasing the concentration and the temperature, it is still difficult to completely remove the polyimide resin by etching. For the purpose of improving etching power, for example, US Pat. No. 3,361,589.
No. 3770528 proposes the use of glycols in addition to U.S. Pat. No. 3,770,528. However, these etching solutions also have a weak etching power, cannot completely remove the polyimide resin by etching, and only roughen the surface of the polyimide resin.

Further, Japanese Patent Publication No. 61-4850 proposes to improve the etching power by adding a specific alcohol such as ethanol, n-propanol or isopropanol to an aqueous solution of a basic compound. These etching solutions have a low dissolving power for the decomposed polyimide resin, and after the polyimide resin is contacted with the etching solution, it takes a long time to remove the gel-like substance generated on the resin surface by absorbing water and swelling by washing with water. In addition, in propanol, there are problems that the liquid is separated into two layers, a uniform solution cannot be obtained, and handling is difficult.

It has been shown that methanol has no effect of improving the etching power.

On the other hand, JP-A-58-108230 proposes the use of a solution of a quaternary ammonium hydroxide and a polar organic solvent, which is effective for a polyamic acid film which is a polyimide precursor. However, it is known that the etching effect is low for a completely cured polyimide resin. Therefore, in order to obtain an etching solution capable of etching and removing the completely cured polyimide resin at a high rate, a further improved method is required.

[0008]

SUMMARY OF THE INVENTION The present invention is extremely high in solving the above-mentioned drawbacks of the prior art, that is, by using a specific composition solution which is safe to handle with respect to a completely cured polyimide resin. The present invention seeks to provide an etching solution that can be etched at a rate.

[0009]

DISCLOSURE OF THE INVENTION The inventors of the present invention have developed a four-component composition comprising water, a basic compound, an aprotic organic solvent compatible with water, and a protic organic solvent compatible with water. By using a solution containing as an essential component as an etching solution, even when using methanol, which has not been conventionally known to have an effect of improving etching power, a completely cured polyimide resin can be treated at a higher rate than a conventional etching solution. The inventors have found that etching is possible, which is beyond the analogy of the prior art.

The aprotic organic solvent having compatibility with water used in the present invention is a ketone type, ether type,
And one or more compounds selected from amide solvents, preferably acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, dimethylacetamide,
Examples thereof include N-methylpyrrolidone and the like, and more preferable examples are methyl ethyl ketone, tetrahydrofuran, dioxane, N-methylpyrrolidone and the like.

The aprotic organic solvent compatible with water is 5 to 85% by weight in the etching solution, preferably
15 to 70% by weight is contained.

The water-compatible protic organic solvent used in the present invention is at least one compound selected from alcohol-based, glycol-based, and glycol ether-based solvents, preferably methanol, ethanol, or 1 -Propanol, 2-propanol, ethylene glycol, propylene glycol, ethoxy ethanol and the like can be mentioned, but methanol and ethanol are more preferable.

The protic organic solvent compatible with water is contained in the etching solution in an amount of 5 to 85% by weight, preferably 15 to 70% by weight.

The basic compound used in the present invention is selected from alkali metal hydroxides and quaternary ammonium hydroxides, preferably alkali metal hydroxides,
More preferred are sodium hydroxide and potassium hydroxide. The basic compound is used in the etching solution in an amount of 0.5 to 30% by weight, preferably 3 to 20% by weight.

The polyimide resin treated with the etching solution of the present invention is generally in the form of a film.

[0016]

[Chemical 1]

(In the formula, n represents the degree of polymerization, arrows represent isomerism, R 1 is a tetravalent organic group containing at least 2 carbon atoms, and the carbonyl group of each polyamic acid unit is not more than 2. R2 is a divalent organic group bonded to any one carbon atom of the tetravalent group and containing at least two carbon atoms, and the amide groups of adjacent polyamic acid units are each separated from the divalent group. To a carbon atom). Such a polyimide resin may be used alone or may be a mixed polyimide resin.

Further, the temperature of the etching solution of the present invention and the contact time with the material to be treated are mutually dependent on the desired etching rate and degree, and the mode of use of the etching solution depends on the material to be treated. May be immersed in the etching solution, or the etching solution may be sprayed on the material to be treated, and any method can be adopted.

[0019]

The etching solution obtained by the present invention is inexpensive, safe and easy to handle, and can remove completely cured polyimide resin by etching at a high rate, and its industrial value is extremely high. It is a thing.

[0020]

EXAMPLES In order to make the present invention easier to understand, the following examples are given, but the present invention is not limited thereto. Example 1 After dissolving 5 g of potassium hydroxide in 19 g of distilled water, N-
An etching solution was prepared by adding it to a solution consisting of 57 g of methylpyrrolidone and 19 g of methanol. The liquid temperature of this solution was kept at about 50 ° C., and 1 sample of a polyimide film “Kapton” 200 V (manufactured by DuPont) weighed here was used.
It was immersed for 2 minutes. After taking out the sample and thoroughly washing it with water,
Weight loss was measured, and the rate of weight loss per hour was taken as the etching rate. The results are shown in Table 1.

Example 2 5 g of potassium hydroxide was dissolved in 19 g of distilled water and then added to a solution of 38 g of tetrahydrofuran and 38 g of methanol to prepare an etching solution. The liquid temperature of this solution was kept at about 50 ° C., and a sample of 200 V of polyimide film “Kapton” weighed therein was immersed for 20 minutes.
After the sample was taken out and washed thoroughly with water, the weight loss was measured, and the rate of weight loss per hour was taken as the etching rate.
The results are shown in Table 1.

Example 3 After dissolving 5 g of potassium hydroxide in 19 g of distilled water, 1,
An etching solution was prepared by adding it to a solution consisting of 57 g of 4-dioxane and 19 g of methanol. The liquid temperature of this solution was maintained at about 50 ° C., and a sample of the polyimide film “Kapton” 200 V weighed here was immersed for 12 minutes.
After the sample was taken out and washed thoroughly with water, the weight loss was measured, and the rate of weight loss per hour was taken as the etching rate.
The results are shown in Table 1.

Example 4 After dissolving 5 g of potassium hydroxide in 19 g of distilled water, N-
An etching solution was prepared by adding it to a solution consisting of 38 g of methylpyrrolidone and 38 g of ethanol. The liquid temperature of this solution was kept at about 50 ° C., and a sample of 200 V of polyimide film “Kapton” weighed therein was immersed for 10 minutes. After the sample was taken out and washed thoroughly with water, the weight loss was measured, and the rate of weight loss per hour was taken as the etching rate. The results are shown in Table 1.

Example 5 After dissolving 5 g of potassium hydroxide in 19 g of distilled water, N-
An etching solution was prepared by adding it to a solution consisting of 19 g of methylpyrrolidone and 57 g of ethanol. The liquid temperature of this solution was kept at about 50 ° C., and a sample of 200 V of polyimide film “Kapton” weighed therein was immersed for 10 minutes. After the sample was taken out and washed thoroughly with water, the weight loss was measured, and the rate of weight loss per hour was taken as the etching rate. The results are shown in Table 1.

Example 6 After dissolving 5 g of potassium hydroxide in 19 g of distilled water, 1,
An etching solution was prepared by adding it to a solution consisting of 19 g of 4-dioxane and 57 g of ethanol. The liquid temperature of this solution was maintained at about 50 ° C., and a sample of the polyimide film “Kapton” 200 V weighed here was immersed for 12 minutes.
After the sample was taken out and washed thoroughly with water, the weight loss was measured, and the rate of weight loss per hour was taken as the etching rate.
The results are shown in Table 1.

Example 7 25% by weight aqueous solution of tetramethylammonium hydroxide 20
65 g of N-methylpyrrolidone and 15 g of methanol
g was added to prepare an etching solution. The liquid temperature of this solution was kept at 50 ° C., and a sample of the polyimide film “Kapton” 299V weighed here was immersed for 10 minutes. After the sample was taken out and washed thoroughly with water, the weight loss was measured, and the rate of weight loss per hour was taken as the etching rate. The results are shown in Table 1.
Shown in.

Comparative Example 1 5 g of potassium hydroxide was dissolved in 95 g of distilled water to prepare an etching solution, the liquid temperature was maintained at about 50 ° C., and 20 samples of 200 V of polyimide film “Kapton” weighed here were prepared.
Soaked for a minute. After the sample was taken out and washed thoroughly with water, the weight loss was measured, and the rate of weight loss per hour was taken as the etching rate. The results are shown in Table 1.

Comparative Example 2 After dissolving 5 g of potassium hydroxide in 19 g of distilled water, 76 g of methanol was added to prepare an etching solution. The liquid temperature of this solution was kept at about 50 ° C., and a sample of 200 V of polyimide film “Kapton” weighed therein was immersed for 20 minutes. After the sample was taken out and washed thoroughly with water, the weight loss was measured, and the rate of weight loss per hour was taken as the etching rate. The results are shown in Table 1.

Comparative Example 3 After dissolving 5 g of potassium hydroxide in 19 g of distilled water, 76 g of ethanol was added to prepare an etching solution. The liquid temperature of this solution was kept at about 50 ° C., and a sample of 200 V of polyimide film “Kapton” weighed therein was immersed for 20 minutes. The sample was taken out, washed thoroughly with water to completely remove the gel-like substance formed on the film surface, and then the weight loss was measured, and the rate of weight loss per time was taken as the etching rate. The results are shown in Table 1.

[0030]

[Table 1]

Claims (4)

[Claims] 1. A water-soluble aprotic organic solvent compatible with water, a protic organic solvent compatible with water, and a basic compound, which further comprises four components as essential components. Polyimide resin etching solution. 2. The aprotic organic solvent having compatibility with water according to claim 1, wherein the aprotic organic solvent is at least one selected from a ketone-based solvent, an ether-based solvent, and an amide-based solvent. An etching solution of a polyimide resin, which is contained. 3. The protic organic solvent compatible with water according to claim 1, wherein the protic organic solvent is at least one selected from alcohol-based, glycol-based, and glycol ether-based solvents, and 5 to 85% by weight in the etching solution. An etching solution of a polyimide resin, which is contained. 4. The polyimide according to claim 1, wherein the basic compound is selected from alkali metal hydroxides and quaternary ammonium hydroxides and is contained in the etching solution in an amount of 0.5 to 30% by weight. Resin etching solution.