JPH0148300B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyamide-imide-based curable material that cures in response to radiation such as light and electron beams, and is particularly characterized by being photosensitive.

In recent years, there has been a high demand for curable materials that can be cured by light, electron beams, etc. to provide heat-resistant substances, and are mainly used as protective materials, insulating materials, solder resists, adhesives, coating materials, etc. in the electrical and electronic fields. It is also being applied as a heat-resistant photoresist in semiconductor devices.

This type of curable material not only requires good radiation sensitivity properties and excellent heat resistance after sensitive curing, but also exhibits good adhesion to adherends. Also, insulation properties,
It is also desired that the material satisfies various properties such as moisture resistance and chemical resistance. On the other hand, it is desired that the material has excellent storage stability without problems such as gelation over time in a solvent-free or organic solvent-containing state before sensitive curing with radiation.

However, there are few conventionally known curable materials that satisfy all of these required properties. Generally, materials with excellent radiation sensitivity tend to have poor storage stability, and many also lack adhesive strength to adherends.

For example, a photocurable heat-resistant photoresist is made by blending dichromate with polyamic acid that has not been completely imidized by reacting a polyimide precursor, that is, an aromatic tetracarboxylic acid component with a diamine. Are known. However, this type of material has extremely poor storage stability and must be used immediately after mixing the polyimide precursor and dichromate, which has major limitations on industrial application. Furthermore, since inorganic ions are included in the hardened material, its reliability is impaired when it is applied to semiconductor applications.

In addition, as another known heat-resistant photoresist, 1 mol of aromatic tetracarboxylic acid anhydride is reacted with 2 mol of allyl alcohol, then two free carboxyl groups are chlorinated, and then a condensation reaction is performed with a diamine. There is a polyimide precursor. However, this type of material also has some problems in terms of storage stability, and the above-mentioned condensation reaction removes chlorine ions, which are then included in the cured resist, so it is still not suitable for semiconductor applications. There was a risk that its reliability would be impaired.

From this viewpoint, the present invention aims to provide a radiation-sensitive polyamide-imide-based curable material that does not have the drawbacks of conventionally known curable materials as described above and satisfies all of the above-mentioned required properties. , its gist is that it is an organic solvent synthesized using an aromatic tricarboxylic acid or its derivative as a polybasic acid component and an aromatic tricarboxylic acid monoester having a polymerizable carbon-carbon double bond in the ester moiety. It is a radiation-sensitive polyamide-imide-based curable material mainly composed of soluble polyamide-imide.

Thus, in the present invention, an aromatic tricarboxylic acid or a derivative thereof is used and reacted with a difunctional nitrogen-containing compound such as a diamine or diisocyanate to form the following structural formula: (However, in the formula, Y represents a trivalent aromatic group and R ₁ represents a divalent organic group.) In addition to the above-mentioned aromatic tricarboxylic acid or its derivative, an aromatic tricarboxylic acid monoester having a polymerizable carbon-carbon double bond in the ester moiety is used, and the reaction of this with a difunctional nitrogen-containing compound results in the following: Structural formula; (However, in the formula, X is a trivalent aromatic group, R ₁ is a divalent organic group, and R ₂ is a monovalent organic group having a polymerizable carbon-carbon double bond.) was synthesized, thereby synthesizing an organic solvent-soluble polyamide-imide having both the above-mentioned amide structure as a repeating unit as well as the amide-imide structure represented by the above-mentioned structural formula (1) in its molecular skeleton. It has been found that it is extremely suitable as a radiation-sensitive curable material.

That is, the above polyamideimide has the structural formula (2)
In the R ₂ group of the amide structure represented by, that is, the ester part of the aromatic tricarboxylic acid monoester,
Because it contains polymerizable carbon-carbon double bonds, it can be cured very well by radiation such as light and electron beams, and it can be cured in a short period of time, especially when photocuring. Therefore, extremely useful photosensitive materials can be provided.

In addition, in the product cured in this way, the amide structure in structural formula (2) can be converted to an amide-imide structure by further high-temperature heat treatment, and the structural formula ( It exhibits excellent heat resistance due to the amide and imide bonds represented by formula (1) and derived from structural formula (2), and also has good adhesion to adherends, for example, with conventional curable materials. Although etching treatment on the surface of the adherend was required to improve adhesive strength, practical adhesive strength can be obtained without such treatment, and in addition, it has improved insulation properties, moisture resistance, and chemical resistance. It is also possible to fully satisfy various properties such as properties.

On the other hand, as mentioned above, polyamide-imide before being cured by radiation is a very good material that does not gel in a short period of time even if it is left at room temperature in a solvent-free or organic solvent-containing state. It exhibits storage stability, and in this respect also has the advantage that, unlike the conventionally known photocurable heat-resistant photoresists, there are no major restrictions on industrial application.

In order to synthesize the organic solvent-soluble polyamideimide having the above characteristics in the present invention, for example, the following structural formula; trimellitic anhydride represented by and the following general formula; (However, in the formula, R ₂ represents a monovalent organic group having a polymerizable carbon-carbon double bond.)
It may be reacted with a diisocyanate compound represented by the following general formula: OCN—R ₁ —NCO (5) (in the formula, R ₁ represents a divalent organic group).

Furthermore, in the above method, trimellitic anhydride represented by structural formula (3) can be replaced with other aromatic tricarboxylic acid monoanhydride, such as hemimellitic anhydride, and trimellitic anhydride represented by general formula (4) can be replaced with The acid monoester can be replaced with another aromatic tricarboxylic acid monoester in the same manner as above. In this case, the aromatic tricarboxylic acid monoester is preferably the same type of monoester as the aromatic tricarboxylic acid monoanhydride used together, but a different type of monoester may be used depending on the case.

In this invention, the most suitable aromatic tricarboxylic acid monoanhydride is trimellitic anhydride of the above structural formula (3), and in this case, the most suitable aromatic tricarboxylic acid monoester is the above general formula (4). The trimellitic acid monoester represented by: Hereinafter, these will be explained in detail as representative examples.

A part of the trimellitic anhydride in the above reaction can be replaced with aromatic or aliphatic dianhydride, but if this amount increases, storage stability and other properties will be adversely affected. 10% by weight of the total amount with trimellitic anhydride
It should be: Specific examples of these dianhydrides include pyromellitic anhydride, benzophenone-
3,4,3',4'-tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride, perylene-2,3,9,10-tetracarboxylic dianhydride , 3,3',4,4'-diphenyltetracarboxylic dianhydride, 2,2',3,3'-diphenyltetracarboxylic dianhydride, 2,2-bis(3,4-dianhydride) carboxyphenyl)propane dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, ethylenetetracarboxylic dianhydride, 1 , 2,3,4-butanetetracarboxylic dianhydride and the like. These can be used alone or in combination of two or more.

The trimellitic acid monoester represented by the general formula (4) is usually composed of trimellitic anhydride and the general formula
It can be synthesized by reacting with an alcohol represented by R ₂ OH (R ₂ is the same as above). The above alcohols can be widely applied as long as they have a polymerizable carbon-carbon double bond in their molecules, but
Particularly preferable ones are the following general formula (6),
Compounds represented by (7) and (8) can be mentioned.

Ra−CH=CH−CH ₂ OH ……(6) (However, Ra is hydrogen or phenyl group) (However, Rb, Rc and Rd are each hydrogen or methyl group, and n is an integer from 1 to 20.) (However, Re is hydrogen or nitrile group, Rf and Rg are each hydrogen or methyl group, m is 1
(an integer of ~20) The trimellitic acid monoester represented by the general formula (4) as described above is usually 5 to 60 mol%, preferably 30 to 50 mol% of the total amount with trimellitic anhydride. used in If this amount is too large, it will become difficult to synthesize polyamideimide with a high degree of condensation through a polycondensation reaction with a diisocyanate compound, resulting in a loss of film-forming ability, and properties such as heat resistance may also be impaired. On the other hand, if it decreases too much, the radiation sensitivity characteristics will deteriorate.

In addition, trimellitic acid monoester is 95
Up to mol %, preferably up to 50 mol %, of the dibasic carboxylic acid may be replaced with a common dibasic carboxylic acid.
When such dibasic carboxylic acids are used together,
In addition to the amide structure represented by the above structural formula (2), an amide bond based on the above dibasic carboxylic acid is introduced into the molecular skeleton.

The dibasic carboxylic acids mentioned above are preferably aromatic ones, but aliphatic or alicyclic carboxylic acids can also be used in combination within a range of 10 mol% or less.
Specific examples of aromatic dibasic carboxylic acids include isophthalic acid, terephthalic acid, 2,6-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, methyl isophthalic acid, and methyl. Terephthalic acid, biphenyl-2,2'-dicarboxylic acid, biphenyl-2,
3'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, etc. can be mentioned. Examples of aliphatic or alicyclic dibasic carboxylic acids include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, malonic acid,
3,9-bis(2-carboxyethyl)-2,
Examples include 4,8,10-tetraoxaspiro[5,5]undecane.

The isocyanate compound represented by general formula (5) is preferably aromatic, but in some cases
Aliphatic or alicyclic compounds may be used in combination within a range of 10 mol% or less. Specific examples of aromatic diisocyanate compounds include dianiridine diisocyanate, bistolylene diisocyanate,
Naphthalene diisocyanate, m-(or P
--) phenylene diisocyanate, 2,4-(or 2,6-)tolylene diisocyanate, diphenyl ether diisocyanate, diphenylmethane diisocyanate, m-(or P-)xylidene diisocyanate, and the like. In addition, examples of aliphatic or alicyclic diisocyanate compounds include methylcyclohexane diisocyanate, dicyclohexylmethane diisocyanate,
Examples include isopropylidene bis(4-cyclohexyl isocyanate), dicyclohexyl ether diisocyanate, and hexamethylene diisocyanate.

The proportions of the above diisocyanate compound and the polybasic acid component consisting of trimellitic anhydride (or trimellitic anhydride and dianhydride) and trimellitic acid monoester (or these and the dibasic carboxylic acid mentioned above) are generally equimolar. The excess amount of the diisocyanate compound may be 10 mol % or less.

The reaction between the polybasic acid component and the diisocyanate compound in such proportions is preferably carried out by heating in an organic solvent. As the organic solvent, one that can dissolve at least one of the two components and is inert to both components is used. Preferably, one that can dissolve both components and dissolve the reaction product polyamideimide is used. do. Examples of preferred solvents include N-methyl-2-
pyrrolidone, N,N-dimethylacetamide,
Examples include N,N-dimethylformamide, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylphosphoramide, N-methylformamide, formamide, and N-acetyl-2-pyrrolidone. These organic solvents may be used alone or in combination of two or more. If desired, benzene, toluene, xylene, chlorobenzene,
There is no problem in using a non-polar solvent such as naphtha.

The amount of organic solvent used is not particularly limited as long as polyamideimide having film-forming ability is obtained, but generally, the concentration of polyamideimide is 10 to 60%.
It may be used in a proportion of % by weight.

The reaction temperature and reaction time vary depending on the type of polybasic acid component, diisocyanate compound, and organic solvent used, but are usually 80 to 120°C.
The reaction may be carried out at a temperature slightly higher than the above temperature until the desired intrinsic viscosity is obtained. If the temperature is too high, for example over 140°C, the amide structure represented by the above structural formula (2) may be converted to an amide-imide structure during the reaction, and in this case, the radiation sensitivity characteristics of the polyamide-imide produced may be affected. This is not preferable because it impairs storage stability, etc.

The intrinsic viscosity of the produced polyamideimide is N
-C=0.5 at 30°C in methyl-2-pyrrolidone
The viscosity ηinh in g/100ml is usually in the range of 0.2 to 1.5, particularly preferably in the range of 0.4 to 1.0. If the intrinsic viscosity is too low, the film-forming ability will be poor and practicality will be poor.

The organic solvent-soluble polyamideimide of the present invention can be advantageously synthesized by the method described above, but it can also be synthesized by other methods. For example, there is a method in which the synthesis of trimellitic acid monoester and the synthesis reaction of polyamideimide in the above-mentioned method are carried out continuously in the same reaction system. That is, after dissolving trimellitic anhydride in a predetermined organic solvent, the general formula (6),
Polymerizable carbon in the molecule as shown in (7) and (8)
By adding an alcohol having a carbon double bond (R ₂ OH) and heating for a certain period of time or carrying out an esterification reaction at room temperature, a predetermined number of trimellitic acid monoesters can be produced based on the number of charged parts of trimellitic anhydride. A diisocyanate compound is added to the reaction system to carry out the polymerization reaction in the same manner as described above.

Furthermore, although each of the above methods uses a diisocyanate compound as an amide bond- or imide bond-introducing agent, there is a method in which a diamine compound is used instead of the diisocyanate compound. In this method, a monohalide of trimellitic anhydride is used, and each free carboxyl group of the trimellitic acid monoester represented by the general formula (4) or a general dibasic carboxylic acid used as necessary is preliminarily removed. It is desirable to halogenate and subsequently participate in a reaction with a diamine compound. This is because it is difficult to synthesize polyamideimide with a high degree of condensation through reaction with a diamine compound if the free carboxyl group remains as it is. However, such a method is not preferable because halogen ions are released by the reaction with the diamine compound, which limits the use of the material as a curable material. On the other hand, such a problem does not occur in the method using the diisocyanate compound.

The curable material of the present invention is an organic solvent synthesized by the above method, or by replacing trimellitic anhydride or its monoester with other aromatic tricarboxylic acid or its monoester in each of the above methods. It is mainly composed of soluble polyamide-imide, and this polyamide-imide alone can be photocured or electron beam cured, but
When photocuring, it is usually desirable to incorporate a photosensitizer to obtain a practical curing speed.

Examples of the above photosensitizers include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether,
Examples include carbonyl compounds such as benzyl and benzyl dimethyl ketal, organic sulfur compounds such as benzyl sulfide, halogen compounds, and photoreducible dyes. When using a photosensitizer, the amount to be used is
The amount may be 10 parts by weight or less per 100 parts by weight of polyamideimide.

In addition, the curable material of the present invention may include, if necessary, a reactive diluent for ultraviolet curable or electron beam curable resins within a range that does not reduce heat resistance.
A monofunctional or polyfunctional monomer having a double bond may be added. The addition of such optional ingredients does not impair the storage stability characteristic of this type of material.

As mentioned above, the curable material of this invention has excellent storage stability, but
When storing this for a long period of time, it is preferable to store it in a dark room or in a cold room considering its photosensitivity.

On the other hand, in use, the above-mentioned material is applied to an adherend using a bar coater, applicator, spinner, etc., dried under appropriate conditions, and then cured by irradiation with radiation. By performing the heat treatment, the amide structure represented by structural formula (2) is converted into an amide-imide structure by a ring-closing reaction. In order to make these reaction mechanisms easier to understand, trimellitic acid allyl ester was used as the aromatic tricarboxylic acid monoester, an aromatic diisocyanate compound was used as the amide bond or imide bond-introducing agent, and N- was used as the reactive diluent. The reaction mechanism when phenylmaleimide is used is as follows.

In the above reaction example, N-phenylmaleimide is used as a reactive diluent, but other monofunctional or polyfunctional monomers having double bonds may also be used, or similar methods may be used. Even when no reactive diluent is used, it is cured and imidized by a reaction mechanism similar to that described above.

The cured film formed by curing by the above method and heat treatment is composed of aromatic tricarboxylic acid and the general formula
Since it has amide bonds and imide bonds derived from aromatic tricarboxylic acid monoesters as shown in (4), it has various properties such as heat resistance, adhesiveness, insulation properties, moisture resistance, and chemical resistance. It will be of very good quality. When masking irradiation is performed during the above-mentioned curing process, the remaining properties of the irradiated area are immediately restored by developing with a solvent that dissolves the uncured polymer after irradiation and heat treatment each time. It is possible to form a pattern that

Next, examples of this invention will be described. In the following, parts and % mean parts by weight and % by weight, respectively.

Example 1 7.69 g (0.04 mol) of trimellitic anhydride, 15.01 g (0.06 mol) of trimellitic acid monoallyl ester, 26.28 g of diphenylmethane diisocyanate
(0.105 mol) and N-methyl-2-pyrrolidone
Pour 120g into a 300ml four-necked flask,
Start the reaction by heating to 120℃, continue the reaction at the same temperature for 10 hours to release enough carbon dioxide gas, and then
The reaction was continued at 140°C for 10 hours.

The viscosity ηinh (C=0.5g/100ml, in N-methyl-2-pyrrolidone at 30°C) of the polyamideimide thus obtained was 0.40. Polyamide-imide is added to this reaction solution containing polyamide-imide.
To 100 parts, 20 parts of N,N'-diphenylmethane-bismaleimide and 5 parts of benzoin isopropyl ether were added, and the solid content in N-methyl-2-pyrrolidone was adjusted to 30%. It was made into a curable material.

The curable material of Example 1 was subjected to a storage stability test and a photocurable sensitivity test, and the results were as follows.

A. Storage stability test The curable material was left at room temperature to examine changes in properties over time. As a result, no gelation occurred even after two months, and no change in properties was observed visually.

B Photo-curing test The curable material was coated onto the adherend using a bar coater to a dry thickness of 10μ, and was heated at 100℃ for 30 minutes.
It was dried by heating for a minute. Next, pattern mask the above coating surface, and the input per unit length is 80W/
Using two high-pressure mercury lamps with a lamp output of 1 KW and a lamp output of 1 KW, the material was irradiated at a speed of 1 m/min from a distance of 15 cm for photocuring. After photocuring, the coating was immersed in N-methyl-2-pyrrolidone for 30 minutes at room temperature, and the masked areas were dissolved and disappeared, but the cured areas that were not masked remained as they were, leaving a clear pattern. Been formed. After this pattern formation, the imidization reaction was further progressed by heat treatment at 200° C. for 30 minutes to obtain a final cured product.

On the other hand, in the above test, the entire coating film was photocured without a pattern mask, and the cured film was subjected to the same heat treatment as described above.
A thermal decomposition test was carried out at a heating rate of 10 minutes, and the temperature at which the weight loss reached 10% was determined from the thermal decomposition curve, and it was found to be 450°C. Further, the following heat resistance and adhesion tests were conducted and the results were as follows.

<Heat resistance> For those using copper foil as the adherend, 100
℃ and 150℃ for 120 hours, and the cured film was examined to see if there were any abnormalities such as deterioration or peeling, but no abnormalities were observed at either temperature.

<Adhesion> For adherends such as copper foil, polyester film, glass, aluminum plate, stainless steel plate, Kapton film, nickel plated plate, aluminum plated plate, etc., cross-cut the cured film into a 2 mm square and apply Nitto Electric Co., Ltd. After pressing No. 29 cellophane tape manufactured by Kogyo Co., Ltd., it was rapidly peeled off and the number of peeled pieces in 100 cross-cuts was determined. All results were 0/100.

Example 2 To the polyamideimide solution obtained in Example 1,
N without adding photosensitizers or reactive diluents
A 30% solution of -methyl-2-pyrrolidone was prepared, and this was used as it was as the curable material of the present invention. A test similar to the photocurability test described above was conducted on this material, except that electron beam irradiation was used as a curing means at an acceleration voltage of 1.3 MeV and an absorbed dose of 10 Mrad. Pattern developability, heat resistance and adhesion were as good as in the case of photocuring.

Example 3 The number of moles of trimellitic acid monoallyl ester used per 0.04 mole of trimellitic anhydride was 0.056.
Polyamideimide was synthesized in the same manner as in Example 1, except that 0.004 mol of pyromellitic anhydride was used as a polybasic acid component other than these. ηinh of this polyamideimide (C=0.5
g/100ml in N-methyl-2-pyrrolidone at 30°C)
was 0.36. To this reaction solution containing polyamide-imide, 5 parts of benzoin isopropyl ether was added to 100 parts of polyamide-imide, and the solid content was
The curable material of this invention was adjusted to 30%.

When this material was subjected to the same photocuring test as in Example 1, it was possible to form a clear cured pattern, and the heat resistance was also good, with a 10% weight loss temperature of 465
℃, adhesion was 0/100.

Example 4 Diphenyl ether diisocyanate instead of 0.105 mol of diphenylmethane diisocyanate
Polyamideimide was synthesized in the same manner as in Example 1 except that 0.105 mol was used. The ηinh (same as above) of this polyamideimide was 0.45.
5 parts of benzoin isopropyl ether was blended with 100 parts of polyamide-imide into the reaction solution containing this polyamide-imide to obtain a curable material of the present invention.

When this material was subjected to the same photocuring test as in Example 1, it was possible to form a clear cured pattern, and the heat resistance was also good, with a 10% weight loss temperature of 420
℃, adhesion was 0/100.

Example 5 The number of moles of trimellitic acid triallyl ester used per 0.04 mole of trimellitic anhydride was 0.045.
Same as Example 1, except that 0.015 mol of terephthalic acid was used as a polybasic acid component other than these, and 0.107 mol of diphenyl ether diisocyanate was used instead of 0.105 mol of diphenylmethane diisocyanate. Polyamideimide was synthesized using the following method. The ηinh (same as above) of this polyamideimide was 0.35. To this polyamide-imide solution, 5 parts of benzoin isopropyl ether was added to 100 parts of polyamide-imide, and the solid content was adjusted to 30% to obtain a curable material of the present invention.

When this material was subjected to the same photocuring test as in Example 1, it was possible to form a clear cured pattern, and the heat resistance was also good, with a 100% weight loss temperature of 416
℃, adhesion was 0/100.

Claims (1)

[Claims] 1 As a polybasic acid component, an aromatic tricarboxylic acid or its derivative and an aromatic tricarboxylic acid monoester having a polymerizable carbon-carbon double bond in the ester moiety are used, with the latter monoester being 5 to 60 moles in the total amount of both. A radiation-sensitive polyamide-imide containing an organic solvent-soluble polyamide-imide synthesized in combination in a proportion of %, and a photosensitizer in a proportion of 0 to 10 parts by weight based on 100 parts by weight of the polyamide-imide. curable material.