JP2011148934A - Curing agent, curable resin composition, adhesive for semiconductor, and method for controlling curing reaction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel curing agent having a high curing starting temperature and being useful as a latent curing agent. <P>SOLUTION: The curing agent contains a salt or an adduct formed from a nitrogen-containing compound represented by formula (1), (2) or (3) and a naphthalenecarboxylic acid. In the formula. R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>, R<SP>4</SP>, R<SP>5</SP>and R<SP>6</SP>each independently represents an organic group and may be bonded to each other to form a cyclic structure containing a nitrogen atom. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a curing agent, a curable resin composition, a semiconductor adhesive, and a method for controlling a curing reaction.

  Amines such as alkylamines and imidazole derivatives have high reactivity with epoxy resins, and are frequently used as curing agents or curing accelerators in electronic materials, for example. However, since amines are highly reactive, they react with an epoxy resin or the like at a low temperature, so that the storage stability is poor and the reaction control is difficult.

  Thus, various methods for imparting latent properties to amines have been studied (Patent Documents 1 to 3). Typical methods include a method of encapsulating amines (especially imidazole derivatives) with an organic substance, a method of reacting an acid or the like with amines to form a salt or an adduct, etc. (Patent Documents 4 to 8). ).

Japanese Patent No. 2709882 Japanese Patent No. 2777761 Japanese Patent No. 3270775 Japanese Patent Publication No. 07-005708 Japanese Patent Application Laid-Open No. 61-210076 Japanese Patent Laid-Open No. 08-113561 Japanese Patent Laid-Open No. 08-225753 Japanese Patent No. 40226679

  However, in the case of encapsulation, since the capsule film covering the amines is generally organic, the solvent resistance is not sufficient, and the capsule may be instantly dissolved by the solvent. Therefore, there is a problem that it can be used only in a limited solvent. Further, since it is difficult to form a uniform capsule film, it is also difficult to control the reaction.

  On the other hand, since most of salts or adducts formed from amines and acids are dissociated by heat, they are less likely to be decomposed by a solvent and can be used in a wider range of applications. However, depending on the application, it is required to increase the reaction start temperature. When the reaction start temperature becomes high, the storage stability is also improved.

  Accordingly, an object of the present invention is to provide a novel curing agent having a high curing start temperature and useful as a latent curing agent.

  Furthermore, an object of the present invention is to provide a novel method for easily controlling the activity of the curing reaction of the curable resin. In applications such as adhesives for semiconductors, it is very useful if the activity of the curing reaction can be easily controlled according to the type of adherend.

The present invention relates to a curing agent containing a salt or an adduct formed from a nitrogen-containing compound represented by the following general formula (1), (2) or (3) and naphthalenecarboxylic acid. R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ in the formula each independently represent an organic group, and may be bonded to each other to form a cyclic structure containing a nitrogen atom.

  The curing agent according to the present invention has a high curing start temperature and is useful as a latent curing agent.

  The nitrogen-containing compound is preferably imidazole or a derivative thereof.

  The naphthalenecarboxylic acid has two or more carboxyl groups bonded to the naphthalene ring, and two carbon atoms to which two carboxyl groups selected from these carboxyl groups are bonded are adjacent to each other in the naphthalene ring. Preferably not in position.

  In another aspect, the present invention relates to a curable resin composition containing the curing agent according to the present invention and an epoxy resin. The curable resin composition according to the present invention may contain the nitrogen-containing compound represented by the general formula (1), (2) or (3), naphthalenecarboxylic acid, and an epoxy resin. Good. The curable resin composition according to the present invention is particularly useful as an adhesive for semiconductors.

  In yet another aspect, the present invention relates to a method for controlling the curing reaction of a curable resin composition. According to the method of the present invention, a nitrogen-containing compound represented by the above general formula (1), (2) or (3), a naphthalene ring, a carboxyl group bonded to the naphthalene ring, and a naphthalene having another substituent In a curable resin composition containing a curing agent containing a salt or an adduct formed from a carboxylic acid, and an epoxy resin, at least one of the type, number and substitution position of the other substituents By selecting, the activity of the curing reaction of the curable resin composition is controlled.

  By selecting one of the types, number, and substitution positions of substituents other than the carboxyl group that replaces the naphthalene ring of naphthalenecarboxylic acid, the activity of the curing reaction of the curable resin composition is maintained while maintaining other characteristics. It can be controlled easily. Depending on the type of substituent and the substitution position, the curing agent has a dramatic potential. In addition to increasing the reaction start temperature, the reaction behavior such as the reaction rate can be variously changed. Particularly in the case of adhesives for semiconductors, it is very useful to be able to control the activity of the curing reaction while maintaining other properties such as reliability after curing.

  According to the present invention, a novel curing agent having a high curing start temperature and useful as a latent curing agent is provided. Since the cured product formed by curing the curable resin composition containing the curing agent according to the present invention has excellent heat resistance and moisture resistance, the adhesive for semiconductors according to the present invention is used. A semiconductor device having high reliability can be manufactured.

  Moreover, according to this invention, the novel method which controls easily the activity of hardening reaction of curable resin is provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

  The curing agent according to this embodiment contains a compound (salt or adduct) formed by a reaction between a nitrogen-containing compound containing a nitrogen atom having an unshared electron pair and naphthalenecarboxylic acid. The nitrogen-containing compound containing a nitrogen atom having an unshared electron pair is represented by, for example, the general formula (1), (2), or (3).

The nitrogen-containing compound only needs to contain a nitrogen atom having an unshared electron pair, and in particular, R ¹ , R ² , R ³ , R ⁴ , R ^5, and R ⁶ that are organic groups constituting other parts. There is no limit. The nitrogen-containing compound is selected from, for example, primary alkylamines, secondary alkylamines, tertiary alkylamines, arylamines and heterocyclic amines. Examples of the heterocyclic amine include pyridine, pyrrole, quinoline, imidazole, indole, pyrimidine, pyrrolidine, piperidine, triazine, and derivatives thereof. In addition, compounds having a cyano group and diazo compounds can also be used. From the viewpoint of handling and stability, the nitrogen-containing compound to be reacted with naphthalenecarboxylic acid is a primary alkylamine, secondary alkylamine, tertiary alkylamine, arylamine, imidazole or a derivative thereof, triazine or a derivative thereof. And at least one selected from the group consisting of compounds having a cyano group.

  Among these, imidazole or a derivative thereof is particularly preferable. When there is a bulky substituent in the vicinity of the nitrogen atom having an unshared electron pair of the nitrogen-containing compound, it tends to be difficult to form an adduct or salt with naphthalenecarboxylic acid. The imidazole derivative as a nitrogen-containing compound to be reacted with naphthalenecarboxylic acid is preferably 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5- Hydroxymethylimidazole, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl) -(1 ')]-ethyl-s-triazine and 2,4-di Selected from amino-6- [2'-undecylimidazolyl- (1 ')]-ethyl-s-triazine.

  Naphthalenecarboxylic acid is a compound having a naphthalene ring and one or more carboxyl groups that replace the naphthalene ring. From the viewpoint of easy formation of a salt or adduct with a nitrogen-containing compound, it is preferred that there is no substituent at the ortho position of the carboxyl group. Due to the absence of a substituent at the ortho position, the reaction initiation temperature of the curable resin composition tends to increase. Moreover, when the carboxyl group couple | bonded with a naphthalene ring increases, there exists a tendency for reaction start temperature to become high. If there are no substituents in the vicinity of the carboxyl group that would interfere with the formation of the salt or adduct, the higher the acidity of the carboxyl group, the easier it is to form the salt or adduct, and reaction such as epoxy resin The starting temperature becomes high. Furthermore, when the naphthalenecarboxylic acid has an electron-withdrawing substituent that replaces the naphthalene ring, the acidity of the carboxyl group is improved and the reaction start temperature is increased. Examples of the electron-withdrawing substituent include a cyano group, a nitro group, a trimethylamino group, an aryl group, an alkylcarbonyl group (such as a methylcarbonyl group), an alkyloxycarbonyl group (such as an ethyloxycarbonyl group), a fluoro group, a chloro group, It is at least one selected from an iodo group and a bromo group. Among these, a cyano group, a nitro group, and a trimethylamino group are preferable because they are substituents that particularly increase the acidity of the carboxylic acid.

  Specific examples of suitable naphthalenecarboxylic acids include 1,4-dicarboxylic acid naphthalene, 2,6-dicarboxylic acid naphthalene and 1,4,5,8-tetracarboxylic acid naphthalene.

  The activity of the curing reaction of the curable resin composition containing a compound (salt or adduct) formed by the reaction of a nitrogen-containing compound and naphthalenecarboxylic acid as a curing agent, the type, number, and number of substituents other than the carboxyl group Control can be performed by selecting at least one of the substitution positions. The stronger the electron withdrawing property of the substituent, the higher the reaction start temperature. There is a tendency that the reaction initiation temperature becomes higher as the number of electro-withdrawing substituents bonded to the naphthalene ring increases. When the reaction start temperature is increased, the activity of the curing reaction at room temperature is suppressed, and high thermal potential is obtained.

  The reaction between the nitrogen-containing compound and naphthalenecarboxylic acid can be performed by a method of mixing both in a solvent. Specifically, for example, a solution in which a nitrogen-containing compound is dissolved and a solution in which naphthalenecarboxylic acid is dissolved are mixed while stirring with a spinner or the like, and the reaction is preferably performed at 0 to 100 ° C. for 1 to 60 minutes.

  A solvent in which at least one of the nitrogen-containing compound and naphthalenecarboxylic acid is dissolved is preferable, and a solvent that does not cause inconvenience in the use of the curable resin composition may be used.

  The molar ratio of the nitrogen-containing compound to naphthalenecarboxylic acid during the reaction is preferably 0.3 to 3, more preferably 0.5 to 3. It is preferable to adjust the molar ratio appropriately so that unreacted nitrogen-containing compound and naphthalenecarboxylic acid do not remain.

  After the reaction, the produced salt or adduct can be isolated by filter paper, filtration, distillation or the like. When the solvent remains, heat treatment may be performed in an oven or the like, or it may be dried under reduced pressure. You may use for the preparation of curable resin composition as a hardening | curing agent, making it melt | dissolve in a solvent, without isolating the produced | generated salt or adduct. By omitting the step of isolating or drying the solvent, the curing agent can be obtained in a simpler step.

  The said hardening | curing agent is used suitably as a hardening | curing agent for epoxy resins. The epoxy resin is preferably a compound having two or more epoxy groups. For example, bisphenol A type, bisphenol F type, naphthalene type, phenol novolak type, cresol novolak type, phenol aralkyl type, biphenyl type, triphenylmethane type, dicyclopentadiene type, various polyfunctional epoxy resins can be used. These can be used alone or as a mixture of two or more.

  The curable resin composition may each contain a nitrogen-containing compound and naphthalenecarboxylic acid alone. Again, the curing reaction activity can be controlled.

  In addition to the compound (salt or adduct) formed by the reaction of the nitrogen-containing compound and the carboxylic acid and the epoxy resin, the curable resin composition according to the present embodiment has other components such as other curing agents and fillers. May further be contained.

  As other curing agents, the following phenol resins, amine-based curing agents, imidazoles and phosphines can be used.

(I) Phenol resin For example, phenol novolak, cresol novolak, phenol aralkyl resin, cresol naphthol formaldehyde polycondensate, triphenylmethane type polyfunctional phenol, various polyfunctional phenol resins and the like can be used. These can be used alone or as a mixture of two or more.

(Ii) Acid anhydride-based curing agent For example, methylcyclohexanetetracarboxylic dianhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, ethylene glycol bisanhydro trimellitate, etc. are used. be able to. These can be used alone or as a mixture of two or more.

(Iii) Amine-based curing agent An amine-based curing agent different from the nitrogen-containing compound that forms a salt or adduct with a carboxylic acid may be used. For example, dicyandiamide can be used.

(Iv) Imidazoles Imidazoles alone may be used as a curing agent. For example, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyano-2- Phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]- Ethyl-s-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4' -Methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazoli -(1 ')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethyl Imidazole is mentioned.

(V) Phosphines Examples include triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium tetra (4-methylphenyl) borate, and tetraphenylphosphonium (4-fluorophenyl) borate.

  The kind and addition amount of the filler may be appropriately determined according to the application. For example, an insulating inorganic filler, whisker, or resin filler can be used. Examples of the insulating inorganic filler include glass, silica, alumina, titanium oxide, carbon black, mica, boron nitride, and the like. Among them, silica, alumina, titanium oxide, and boron nitride are preferable, and silica, alumina, and nitride are used. Boron is more preferred. Examples of whiskers include aluminum borate, aluminum titanate, zinc oxide, calcium silicate, magnesium sulfate, and boron nitride. For example, polyurethane, polyimide, or the like can be used as the resin filler. These fillers and whiskers can be used alone or as a mixture of two or more. There is no particular limitation on the shape, particle size, and blending amount of the filler.

  The curable resin composition may contain, for example, an additive selected from an antioxidant, a silane coupling agent, a titanium coupling agent, a leveling agent, and an ion trap agent.

  The curable resin composition may be in any form, and may be, for example, a liquid, a paste, a film, or a powder.

  The curable resin composition preferably contains a polymer component when it is necessary to maintain a shape such as a film. This polymer component includes, for example, phenoxy resin, polyimide resin, polyamide resin, polycarbodiimide resin, cyanate ester resin, acrylic resin, polyester resin, polyethylene resin, polyethersulfone resin, polyetherimide resin, polyvinyl acetal resin, urethane resin. And acrylic rubber. The weight average molecular weight of the polymer component is preferably 10,000 or more.

  The curable resin composition according to the present embodiment is particularly useful as an adhesive for a semiconductor that bonds a semiconductor element and an adherend such as a substrate and other semiconductor elements. Since the carboxylic acid is an organic acid, it exhibits a flux activity that removes the oxide film and impurities on the solder and the copper surface after being separated from the nitrogen-containing compound by heat. Furthermore, unlike other organic acids, carboxylic acid easily reacts with an epoxy resin when separated from a nitrogen-containing compound and is taken into a crosslinked structure and hardly remains as a single substance in the system, so that it has insulation such as HAST resistance. There is also an advantage that deterioration of reliability is suppressed.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

1. Material (a) Nitrogen-containing compound (imidazole derivative)
1-cyanoethyl-2-phenylimidazole (manufactured by Shikoku Kasei Co., Ltd., 2PZCN)
(B) 1,4-dicarboxylic acid naphthalene carboxylate (manufactured by Tokyo Chemical Industry Co., Ltd.)
2,6-dicarboxylic acid naphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.)
1,4,5,8-tetracarboxylic acid naphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.)
(C) Epoxy resin Trifunctional methane skeleton-containing polyfunctional solid epoxy resin (Japan Epoxy Resin Co., Ltd., EP1032H60, hereinafter referred to as “EP1032”)

2. Synthesis of adduct The imidazole derivative and the carboxylic acid shown in Table 1 were mixed with N-methyl-2-pyrrolidone (manufactured by Kanto Chemical Co., hereinafter referred to as “NMP”) at a molar ratio of 1: 1 and a non-volatile content of 3% by mass. Then, the mixture was stirred at room temperature (25 ° C.) for 30 minutes to form an adduct, which is a reaction product of naphthalenecarboxylic acid and 2PZCN, in the solution. The produced adduct was used for the preparation of the curable resin composition as it was in the state of NMP solution without isolation.

3. Preparation of curable resin composition and its evaluation The above adduct was used as a curing agent, and this was mixed with an epoxy resin at a ratio of 0.5 mol with respect to 100 mol of epoxy resin (EP1032). NMP was used as the solvent, and the whole was adjusted so that the nonvolatile content was 40% by mass. After mixing, the mixture was heated at 80 ° C. for 30 minutes and 120 ° C. for 20 minutes in order to remove the solvent to obtain a curable resin composition. In Experimental Example 1, 2PZCN was used as a curing agent as it was. About the obtained curable resin composition, the measurement of the range of 25 degreeC-350 degreeC was performed using DSC (DSC-7 type | mold by Perkin-Elmer Co., Ltd.) with the sample amount of 5 mg and the temperature increase rate of 10 degree-C / min. . From the exothermic peak resulting from the curing reaction, the “reaction start temperature”, “reaction peak temperature”, and “exotherm” were determined. When the vertical axis is calorie (W / g) and the horizontal axis is temperature (° C), the temperature at the intersection of the temperature axis and the tangential line of the peak of the exothermic peak rising curve The starting temperature (onset temperature: mean field approximate first order transition temperature) was used. The measurement results are shown in Table 1 below.

  Compared with Experimental Example 1, Experimental Examples 2 to 4 using naphthalenecarboxylic acid had higher reaction start temperatures. Further, in comparison with Experimental Examples 2 to 3 using naphthalenecarboxylic acid having two carboxyl groups, Experimental Example 4 using carboxylic acid having four carboxyl groups has a larger number of carboxyl groups, Since the group is not bonded to adjacent carbon atoms, the reaction start temperature is particularly high.

Claims (8)

A curing agent containing a salt or an adduct formed from a nitrogen-containing compound represented by the following general formula (1), (2) or (3) and naphthalenecarboxylic acid.

[R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ in the formula each independently represent an organic group, and may be bonded to each other to form a cyclic structure containing a nitrogen atom. ]   The curing agent according to claim 1, wherein the nitrogen-containing compound is imidazole or a derivative thereof.   The naphthalenecarboxylic acid has two or more carboxyl groups bonded to a naphthalene ring, and two carbon atoms to which two carboxyl groups selected from these carboxyl groups are bonded are adjacent to each other in the naphthalene ring. The hardening | curing agent of Claim 1 or 2 which is not in a position.   The curable resin composition containing the hardening | curing agent as described in any one of Claims 1-3, and an epoxy resin. A curable resin composition comprising a nitrogen-containing compound represented by the following general formula (1), (2) or (3), naphthalenecarboxylic acid, and an epoxy resin.

[R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ in the formula each independently represent an organic group, and may be bonded to each other to form a cyclic structure containing a nitrogen atom. ]   The adhesive for semiconductors which consists of a curable resin composition of Claim 4 or 5. A salt formed from a nitrogen-containing compound represented by the following general formula (1), (2) or (3) and a naphthalene ring and a naphthalenecarboxylic acid having a carboxyl group and other substituents bonded to the naphthalene ring, or In the curable resin composition containing the curing agent containing the adduct and the epoxy resin, the curable resin composition is selected by selecting at least one of the type, number, and substitution position of the other substituents. A method for controlling the curing reaction, which controls the activity of the curing reaction of the product.

[R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ in the formula each independently represent an organic group, and may be bonded to each other to form a cyclic structure containing a nitrogen atom. ]   The adhesive for semiconductors which consists of a curable resin composition by which the curing reaction was controlled by the method of Claim 7.