JPH0680598A - Polyhydroxynaphthalene and epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain the title compound which is obtained by co-condensation reaction between alpha- and beta-naphthol and paraformaldehyde, thus contains a specific amount of the component containing a plurality of naphthalene nuclei, and can be used as a curing agent for semiconductor-sealing epoxy resin because it gives heat-resistant and humidity resistant cured products. CONSTITUTION:alpha-, beta-naphthols and formaldehyde is charged in a reactor equipped with a stirring mechanism, a reflux condenser, a thermometer and a nitrogen inlet, and stirred for 8 hours at 110 deg.C in a nitrogen atmosphere to effect co-condensation reactions. Then, the reaction mixture is heated up to 200 deg.C and the unreacting substances are removed under a pressure of 5mmHg. Hg. The co-condensates are determined for its number of naphthalene nuclei and found to include less than 50wt.% of 4 or more nuclei products. Thus, the product is suitable for sealing semiconductors because it has a low melting point and melt viscosity, excellent operability and is used as a curing agent to give cured epoxy resins of high glass transition point, heat resistance and humidity resistance and high crack resistance of the package on welding treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyhydroxynaphthalene compound useful as a curing agent for epoxy resins, and a highly reliable epoxy resin composition for encapsulating semiconductors.

[0002]

2. Description of the Related Art Conventionally, a method of encapsulating with a epoxy resin composition has been widely adopted in order to protect a semiconductor element from the external environment. The composition is usually composed of an epoxy resin, a curing agent, a curing accelerator, a filler, and other additives. As the epoxy resin, a resin obtained by epoxidizing a novolak resin obtained by the reaction of phenols and formaldehyde, particularly an orthocresol novolac epoxy resin is widely used, and a phenol-formaldehyde novolac resin is used as a curing agent. . Further, a novolak resin obtained by reacting α-naphthol and an aldehyde as a high-performance curing agent and an epoxy resin based on this have been introduced, but the melting point and melt viscosity are high, and workability such as molding is poor. It has not been put to practical use. On the other hand, it is reported that β-naphthol is not used because it crystallizes and hardly forms a resin.

In recent years, semiconductor devices have become more highly integrated and larger, and flat packages with a large number of pins have been put into practical use, and the proportion of epoxy resin in the encapsulated devices tends to decrease. For this reason, strong stress is easily applied during sealing, and the mounting method is also the surface mounting method.Since the resin-sealed semiconductor is immersed in molten solder during mounting, strong thermal stress is applied and moisture is absorbed inside the resin. The exposed water is exposed to a severe environment where it vaporizes rapidly and causes volume expansion.

When a large-capacity semiconductor is sealed by using the epoxy resin composition, there arises a problem that cracks are generated in the package, the bonding wires are deformed or broken due to corrosion, and cracks in element passivation occur. There is a problem that tends to occur. For this reason, an epoxy resin using a novolac resin obtained by reacting the α-naphthol and an aldehyde as a curing agent has been proposed, but the problem has not been solved yet.

[0005]

The object of the present invention is that it is useful as a curing agent for epoxy resins, has excellent workability due to its low melting point and melt viscosity, and has a high glass transition temperature and heat resistance after curing with epoxy resins. It is intended to provide a polyhydroxynaphthalene-based compound which has a high resistance and a moisture resistance and gives a cured product capable of preventing a crack from being generated in a package.

An object of the present invention is to provide a novel epoxy resin composition having a high glass transition temperature, excellent heat resistance and moisture resistance, and capable of preventing cracks from being generated in a package.

Another object of the present invention is to provide an epoxy resin composition useful as a semiconductor encapsulating material.

[0008]

Means for Solving the Problems As a result of intensive studies for achieving the above-mentioned object, the present inventors have found that (1) β-naphthol alone does not smoothly react with an aldehyde compound, but α-naphthol Combined with β-naphthol,
Further, paraformaldehyde allows the cocondensation reaction to proceed smoothly. (2) In the obtained cocondensate, the melting point and the melt viscosity are lowered by controlling the content of naphthalene nuclei having a number of 4 or more to a specific amount or less. The workability is excellent, the glass transition temperature after curing is high, and the heat resistance and the humidity resistance are excellent.
They have found that they are useful as a curing agent for epoxy resins and completed the present invention.

That is, the present invention is a curing agent for epoxy resins, wherein the polyhydroxynaphthalene compound obtained by co-condensation of α-naphthol, β-naphthol and paraformaldehyde has a naphthalene nucleus number of 4
Provided is a polyhydroxynaphthalene compound in which the content of the above is 50% by weight or less.

Further, there is provided a polyhydroxynaphthalene compound having a naphthalene nucleus number of 4 or more in the polyhydroxynaphthalene compound of 30% by weight or less.

The present invention further provides an epoxy resin composition containing a curing agent composed of the polyhydroxynaphthalene compound and an epoxy resin. The epoxy resin composition of the present invention containing a polyhydroxynaphthalene compound as a curing agent preferably contains a curing accelerator, and in that case, it is particularly effective as a semiconductor encapsulating composition. In the present specification, the term “epoxy resin” is used to include not only a resinous epoxy compound but also a low molecular weight epoxy compound unless otherwise specified.

(Requirements Constituting Means) One of the requirements for obtaining a polyhydroxynaphthalene-based compound that can provide workability and excellent performance is that the polyhydroxynaphthalene-based compound is an α-naphthol, a β-naphthol and a para-naphthol. It is a co-condensation product with formaldehyde. That is, even if β-naphthol is reacted with an aldehyde compound, the condensation reaction does not proceed and a resinous compound cannot be obtained. However, when β-naphthol is reacted with paraformaldehyde in the presence of α-naphthol, the cocondensation reaction proceeds smoothly and a polyhydroxynaphthalene compound (hereinafter referred to as a cocondensate) is produced.

The second requirement is that the content of naphthalene nuclei in the cocondensation product is 4 or more, and the content is 50% by weight or less. The present inventors paid attention to the content of naphthalene nuclei having a number of 4 or more, and investigated the relationship between the content and the melting point or the melt viscosity at 150 ° C. The result is shown in FIG. In order to achieve a melting point of 120 ° C. or lower and a melt viscosity at 150 ° C. of 20 poise or lower, which are physical properties more preferable than those of FIG. It turned out to be good. Furthermore, the content of naphthalene nuclei with 4 or more is 30% by weight.
When it is below, the melting point is 100 ° C. or less and the melt viscosity at 150 ° C. is 10 poise or less, so that the workability is further improved.

From FIG. 1, when the content of naphthalene nuclei having a number of 4 or more exceeds 50% by weight, the melting point and the melt viscosity rapidly increase, and the mixing property with the epoxy resin deteriorates. It was found that the melting point and melt viscosity of the resin composition became high, precision molding could not be carried out, and the work performance deteriorated.

In the polyhydroxynaphthalene compound of the present invention, the ratio of α-naphthol and β-naphthol can be appropriately selected within the range where a cocondensate is produced.
From the relation of suppression of the generation of high number of nucleosomes by the progress of the reaction, α-
Naphthol: β-naphthol = 85-15: 15-85
(Mol%) is preferable, and 70-30: 30-70 is more preferable.

The amount of paraformaldehyde charged is important because it greatly affects the content of those having 4 or more naphthalene nuclei, and is 0.50 to 0.80 mol per 1 mol of the total of α-naphthol and β-naphthol. Is. When the charged amount of paraformaldehyde is less than 0.50 mol, the heat resistance of the cured product of the epoxy resin composition decreases because the molecular weight of the cocondensate becomes small, and when it exceeds 0.80 mol, the naphthalene nucleus is formed. The melting point of the melting point is increased to 12 by increasing the content of the number 4 or more.
The melt viscosity at 0 ° C. and 150 ° C. exceeds 20 poise, resulting in poor workability and a problem in moldability. In order to set the melting point to 100 ° C. or lower and the melt viscosity at 150 ° C. to 10 poise or lower, 0.55 to 0.70 mol may be used.

The co-condensation reaction for obtaining the polyhydroxynaphthalene compound of the present invention is carried out without using an acid catalyst or a basic catalyst which is usually used in order to easily control the number of naphthalene nuclides, and is simply heated to a high temperature. The condensation reaction of is performed. In this case, the reaction temperature is preferably 80 ° C to 150 ° C, particularly preferably 80 ° C to 130 ° C. Reaction is usually 2
It will be finished in about 10 hours.

Although the reaction can be carried out without using a solvent, toluene having a boiling point of 80 ° C. or higher and a low solubility in water,
It is preferable to use a solvent such as xylene or methyl isobutyl ketone.

After the reaction, if necessary, impurities may be removed by washing with water, or unreacted monomers may be removed by washing with a solvent or degassing under reduced pressure.

The number of naphthalene nuclei in the polyhydroxynaphthalene compound thus obtained was measured by gel permeation chromatography (GPC method). The measurement conditions are as shown below. Was performed using polystyrene of known molecular weight. Solvent: tetrahydrofuran, flow rate: 0.8 ml / min Column: Toyo Soda Industry Co., Ltd. G4000H, G30
00H and G2000H (series), and the exclusion limit molecular weights are 400000, 60000 and 10000, respectively. Carrier: Styrene divinylbenzene copolymer

A second invention comprises the above-mentioned polyhydroxynaphthalene compound which functions as a curing agent, and an epoxy resin. This composition preferably further contains a curing accelerator, and in this case, it is particularly useful as a resin composition for semiconductor encapsulation.

When used as a curing agent for an epoxy resin, the polyhydroxynaphthalene compound may be used alone, and another curing agent comprising a compound having two or more, preferably three or more phenolic hydroxyl groups in the molecule. It can also be used in combination with an agent. As other curing agents, for example, phenol or a substituted phenol (o-cresol, p-cresol, t-butylphenol, cumylphenol, phenylphenol, etc.) and an aldehyde compound are reacted in the presence of an acid catalyst or a basic catalyst. Examples thereof include a usual phenol resin made to react; a reaction product of resorcin and an aldehyde compound; polyvinylphenol and the like. The proportion of the other curing agent is 70 wt% or less, preferably 50 wt% or less in the curing agent.

The type of epoxy resin is not particularly limited, and conventionally known ones can be used. For example, bisphenol A
Type, phenol novolac type, cresol novolac type epoxy resin and the like. Among these resins, those having a melting point above room temperature and exhibiting a solid state or a highly viscous solution state at room temperature give good results.

The bisphenol A type epoxy resin is usually an epoxy equivalent of 160 to 200 and a melting point of 50 to 50.
Those having a temperature of 130 ° C. are used, as the phenol novolac type epoxy resin, those having an epoxy equivalent of 180 to 210 and a melting point of 50 to 130 ° C. are used, and as the cresol novolac type epoxy resin, an epoxy equivalent of 180 to 2 is used.
Those having a melting point of 60 to 110 ° C. are generally used.

The ratio of the epoxy resin and the curing agent is such that the equivalent ratio of the phenolic hydroxyl group of the curing agent to the epoxy group of the epoxy resin (epoxy group / phenolic hydroxyl group) is usually 1 / 0.8 to 1.2, preferably The range of 1 / 0.9 to 1.1 is preferable. When the epoxy resin and the curing agent are used in such a ratio, a cured product having excellent heat resistance and moisture resistance can be obtained.

As the curing accelerator, an ordinary catalyst can be used, and the kind thereof is not particularly limited. Specific examples of the curing accelerator include, for example, triphenylphosphine, tris-2,6-dimethoxyphenylphosphine, tri-p.
-Phosphorus compounds such as tolylphosphine and triphenyl phosphite; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole; Tertiary amines such as 2-dimethylaminomethylphenol, benzyldimethylamine, α-methylbenzylmethylamine; 1,5-diazabicyclo [4.3.0] -5-nonene, 1,4-diazabicyclo [2.2] .2] octane, organic bases of 1,8-diazabicyclo [5.4.0] -7-undecene, and the like.

From the viewpoint of heat resistance and moisture resistance, the amount of the curing accelerator added is preferably 0.1 to 3.0% by weight in the epoxy resin composition.

The epoxy resin composition of the present invention may contain additives as required. Examples of the additive include a filler, a surface treatment agent for treating the surface of the filler, a flame retardant, a release agent, a colorant, and a flexibility-imparting agent.

The kind of the filler is not particularly limited, and examples thereof include crystalline silica powder, fusible silica powder, quartz glass powder,
Talc, calcium silicate powder, zirconium silicate powder,
Examples thereof include alumina powder and calcium carbonate powder. Among these fillers, silica-based fillers are preferable. The proportion of filler is 60-90 wt%, preferably 70-85 wt%, based on the total composition. The amount of filler is 90w
If it exceeds t%, the fluidity of the composition tends to be low and molding tends to be difficult, and if it is less than 60 wt%, the thermal expansion tends to increase.

Examples of the surface treatment agent include known silane coupling agents, and examples of the flame retardant include antimony trioxide, antimony pentoxide, phosphate and bromide. Examples of the release agent include various waxes,
Carbon black etc. are mentioned as a coloring agent.
The flexibility-imparting agent includes, for example, silicone resin and butadiene-acrylonitrile rubber.

The method for preparing the epoxy resin composition of the present invention is not particularly limited, and can be carried out according to a conventional method. Moreover, the conditions for encapsulating a semiconductor using the resin composition of the present invention can be appropriately selected and are not particularly limited. A specific example of the sealing conditions is, for example, 175 ° C., molding pressure 100 kg / cm ² , molding for 3 minutes, and post-curing at 180 ° C. for 5 hours. Usually, it is formed by transfer molding.

[0032]

EXAMPLES Hereinafter, the embodiments of the present invention will be specifically illustrated and described with reference to Examples. The invention is not limited to these examples.

Example 1 (Polyhydroxynaphthalene Compound 1) 96 g of α-naphthol and 4 of β-naphthol were placed in a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet.
8 g and paraformaldehyde 20 g (naphthol: paraformaldehyde = 1: 0.67 (molar ratio)) were charged, heated to 110 ° C. and stirred under a nitrogen stream for 8 hours to react. Then, it heated at 200 degreeC and 5 mmHg removed the unreacted material and water. The number of naphthalene nuclides of the obtained cocondensate was measured. The GPC chart is shown in FIG.
At this time, the content of tetranuclear bodies or more was 28.1% by weight. Further, the melting point was 81 ° C., and the melt viscosity at 150 ° C. was as low as 1.5 poise (hereinafter referred to as P), and the work performance was excellent. In addition, also in the following Examples, all the viscosity measurements were performed at 150 ° C.

Example 2 (Polyhydroxynaphthalene Compound 2) 72 g of α-naphthol, 72 g of β-naphthol and 72 g of xylene were used, and 18 g of paraformaldehyde (naphthol: paraformaldehyde = 1: 0.60 (molar ratio)) was used. A cocondensate was produced in the same manner as in Example 1 except that After condensation, xylene was removed under reduced pressure with heating.
The content of the obtained cocondensate having 4 or more naphthalene nuclei was 17% by weight. The melting point is 73 ° C and the viscosity is 0.
The workability was excellent with a low 3P.

Example 3 (Polyhydroxynaphthalene Compound 3) Using 48 g of α-naphthol, 96 g of β-naphthol and 144 g of toluene, 19 g of paraformaldehyde (naphthol: paraformaldehyde = 1: 0.63 (molar ratio)) was used. A cocondensate was produced in the same manner as in Example 1 except that After condensation, toluene was removed under reduced pressure with heating.
The content of the obtained cocondensate having 4 or more naphthalene nuclides was 20% by weight. The melting point is 78 ° C and the viscosity is 0.
It was as low as 9P and had excellent workability.

Example 4 (Polyhydroxynaphthalene compound 4) 72 g of α-naphthol, 72 g of β-naphthol, 72 g of methyl isobutyl ketone, paraformaldehyde 21.
9 g (naphthol: paraformaldehyde = 1: 0.7
A cocondensate was produced in the same manner as in Example 1 except that the molar ratio was 3 (molar ratio). After condensation of methyl isobutyl ketone,
Removed under heating and reduced pressure. The content of the obtained cocondensation product having 4 or more naphthalene nuclei was 47% by weight. The melting point was 105 ° C. and the viscosity was as low as 19.1 P, and the work performance was excellent.

Comparative Example 1 (Polyhydroxynaphthalene Compound 5) A cocondensate was prepared in the same manner as in Example 1 except that 20 g of paraformaldehyde was changed to 28 g (naphthol: paraformaldehyde = 1: 0.93 (molar ratio)). Was manufactured. The content of the obtained cocondensation product having 4 or more naphthalene nuclei was 58% by weight. Melting point is 135 ° C, viscosity is 32
The workability was poor because of high P and extremely poor fluidity.

Comparative Example 2 (Polyhydroxynaphthalene Compound 6) 0.5 g of paratoluenesulfonic acid was used as a catalyst, and 6% formalin water (35%) was used instead of paraformaldehyde.
A cocondensate was produced in the same manner as in Example 1 except that 0 g was used. The content of the obtained cocondensation product having 4 or more naphthalene nuclides was 61% by weight. Melting point is 128 ℃,
The viscosity was as high as 75P and the workability was poor due to extremely poor fluidity.

Comparative Example 3 (Polyhydroxynaphthalene Compound 7) As Example 1 except that 144 g of α-naphthol, 0.5 g of paratoluenesulfonic acid as a catalyst, and 60 g of formalin water (35%) instead of paraformaldehyde were used. A condensate was produced in the same manner. The content of the obtained cocondensation product having 4 or more naphthalene nuclides was 57% by weight. The melting point was as high as 125 ° C and the viscosity was as high as 70P, and the fluidity was extremely poor, resulting in poor workability.

Examples 5 to 8 and Comparative Example 4 The following epoxy resin, curing agent, curing accelerator, filler, antimony trioxide, silane coupling agent, wax and carbon black were added in the proportions shown in Table 1. The mixture was mixed, kneaded with a two-roll mill at a temperature of 70 to 110 ° C., cooled, and pulverized to prepare an epoxy resin composition for semiconductor encapsulation.

Epoxy resin: o-cresol novolac type epoxy resin Epoxy equivalent 195 melting point 85 ° C. Brominated phenol novolac type epoxy resin Epoxy equivalent 280 melting point 83 ° C. Curing agent: cocondensate obtained in Examples 1 to 4 phenol novolac resin Hydroxyl equivalent 106 Melting point 80 ° C. Curing accelerator: Triphenylphosphine Filler: Spherical silica (BF100 from Mitsubishi Metals Co., Ltd.)

The composition obtained was treated at 175 ° C. and 100 kg.
/ Cm ² , molding under curing conditions for 3 minutes, then 180
Post-cure was performed under the conditions of ° C and 6 hours to prepare a molded test piece. This package is an 80-pin 4-way flat package (80-pin QFP, size: 20 x 14 x 2 m)
m) and the die pad size is 8 × 8 mm.

The semiconductor device thus obtained was subjected to a TCT test of -50 ° C./5 minutes to 150 ° C./5 minutes to check the number of cracks. In addition, the test piece
A test was conducted in which the sample was left in a constant temperature bath having a relative humidity of 5 ° C./85% RH to absorb moisture, and then immersed in a solder melt at 260 ° C. for 10 seconds. The results are shown in Table 2 below.

The bending strength (high temperature strength) of the obtained test piece at 200 ° C., the glass transition temperature, the thermal expansion coefficient,
The water absorption was examined after a humidity test at 85 ° C. and 85% RH for 500 hours. The results are shown in Table 3 below.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

[0048]

The polyhydroxynaphthalene compound of the present invention has a low melting point and melt viscosity and is excellent in workability. Further, when used as a curing agent for epoxy resin, a cured product having a high glass transition temperature, heat resistance and moisture resistance and capable of preventing cracks from being generated in a package even during soldering is provided.

The epoxy resin of the present invention derived from a polyhydroxynaphthalene compound has a high glass transition temperature of a cured product, is excellent in heat resistance and moisture resistance, and prevents cracks from being generated in the package.

The epoxy resin composition of the present invention containing a polyhydroxynaphthalene compound as a curing agent has a high glass transition temperature of the cured resin and excellent heat resistance, a large mechanical strength, a low water absorption rate and a high moisture resistance. Excellent, with very few cracks even during soldering. Therefore, it is useful as a composition for semiconductor encapsulation. Further, the epoxy resin composition preferably contains a curing accelerator, and in that case, it is particularly useful for encapsulating a semiconductor.

[Brief description of drawings]

FIG. 1 is a relationship diagram between the content of a polyhydroxynaphthalene compound having a naphthalene nucleus number of 4 or more and the melting point or the melt viscosity at 150 ° C.

FIG. 2 is a GPC chart of a cocondensate (polyhydroxynaphthalene compound 1) in Example 1.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C09K 3/10 Z H01L 23/29 23/31

Claims (4)

[Claims] 1. A polyhydroxynaphthalene compound obtained by co-condensation of α-naphthol, β-naphthol and paraformaldehyde, wherein the content of naphthalene nuclides of 4 or more is 50% by weight or less. And a polyhydroxynaphthalene compound. 2. The polyhydroxynaphthalene compound according to claim 1, wherein the content of the naphthalene nuclei having a number of 4 or more is 30% by weight or less. 3. An epoxy resin composition comprising a curing agent comprising the polyhydroxynaphthalene compound according to claim 1 and an epoxy resin. 4. An epoxy resin composition for semiconductor encapsulation, comprising a curing agent comprising the polyhydroxynaphthalene compound according to claim 1 or 2 and an epoxy resin.