JP2792395B2 - Curing agent for epoxy resin, epoxy resin composition, and semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention makes it possible to obtain an epoxy resin composition which has good storage stability and fluidity and gives a cured product having excellent properties such as curability, moisture resistance and adhesiveness. The present invention relates to a curing agent for an epoxy resin, an epoxy resin composition, and a semiconductor device.

[0002]

2. Description of the Related Art
As an epoxy resin curing agent, an amine-based curing agent, an acid anhydride-based curing agent, a phenol novolak-type curing agent, and the like are used. These curing agents include imidazole derivatives, tertiary amine compounds, and tertiary curing agents as curing accelerators. Phosphine compounds and their derivatives have been used in combination.

However, if these curing agents and curing accelerators are simply blended in combination, an epoxy that gives a cured product having good storage stability and fluidity and excellent properties such as curability and moisture resistance. It was difficult to obtain a resin composition.

On the other hand, JP-B-56-45491 discloses a novolak type phenol resin curing agent and tetraphenylphosphonium tetraphenylborate (hereinafter referred to as TP).
(Abbreviated as PK)), the use of a curing agent for an epoxy resin obtained by heat-treating the epoxy resin composition can provide an epoxy resin composition having good storage stability and giving a cured product having excellent moisture resistance. Have been described.

[0005] However, the epoxy resin composition containing the curing agent has poor adhesion of the cured product, and when used as a sealing material for surface mounting, peels off due to deterioration such as solder immersion after absorbing moisture, There is a problem that cracks occur.

The present invention has been made in view of the above circumstances,
An epoxy resin curing agent that has good storage stability and fluidity and is capable of obtaining an epoxy resin composition that gives a cured product having excellent properties such as curability, moisture resistance, and adhesiveness is industrially advantageous. It is an object of the present invention to provide a curing agent for an epoxy resin which can be manufactured in a low temperature, an epoxy resin composition using the curing agent, and a semiconductor device sealed with a cured product of the composition.

[0007]

The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have found that an aromatic group containing a phenolic hydroxyl group has 2 to 4 carbon atoms having 3 to 12 carbon atoms. A non-novolak phenol resin having two or more phenolic hydroxyl groups in one molecule and a TPP-K bonded by an aliphatic hydrocarbon group are heated at a temperature not lower than the softening point of the non-novolak phenol resin. By mixing, the storage stability and fluidity are good, and the curability is excellent in moisture resistance, as well as giving a cured product excellent in adhesion, and an epoxy resin composition suitable for semiconductor encapsulation. The present inventors have found that a hardening agent for an epoxy resin that can be obtained can be industrially advantageously produced, and have accomplished the present invention.

Accordingly, the present invention provides a phenolic hydroxyl group in one molecule comprising an aromatic group having a phenolic hydroxyl group and a divalent or tetravalent aliphatic hydrocarbon group having 3 to 12 carbon atoms. And a curing agent for an epoxy resin obtained by heating and mixing a non-novolak phenol resin containing two or more and TPP-K at a temperature not lower than the softening point of the non-novolak phenol resin, and 2 per molecule. Provided are an epoxy resin composition containing an epoxy resin having at least two epoxy groups, the above curing agent, and an inorganic filler, and a semiconductor device sealed with a cured product of the epoxy resin composition.

Hereinafter, the present invention will be described in further detail. As described above, the curing agent for epoxy resin of the present invention comprises a non-novolak phenol resin containing two or more phenolic hydroxyl groups in one molecule, And K by heating and mixing at a temperature equal to or higher than the softening point of the non-novolak phenol resin.

Here, as the non-novolak phenol resin containing two or more phenolic hydroxyl groups in one molecule, an aromatic group containing a phenolic hydroxyl group is a di- to tetra-valent aromatic group having 3 to 12 carbon atoms. Those bonded by an aliphatic hydrocarbon group are used, and specific examples thereof include a cyclopentadiene group-containing phenol resin, triphenolpropane, and a naphthalene ring-containing phenol resin. The non-novolak phenol resin preferably has a softening point of 130 ° C. or lower, particularly preferably 50 to 110 ° C.

The amount of TPP-K is preferably 2 to 50 parts, especially 5 to 30 parts, and more preferably less than 2 parts, based on 100 parts (parts by weight, hereinafter the same) of the non-novolac phenolic resin. When used as a curing agent for an epoxy resin, sufficient curability may not be obtained in some cases, and if it exceeds 50 parts, uniform curability may be difficult to obtain.

In the present invention, two or more phenolic hydroxyl groups are contained in one molecule in which an aromatic group having a phenolic hydroxyl group is bonded by a divalent or tetravalent aliphatic hydrocarbon group having 3 to 12 carbon atoms. A hardener for an epoxy resin is manufactured by heating and mixing a non-novolak phenol resin and TPP-K containing at least one of the non-novolak phenol resins at a temperature not lower than the softening point of the non-novolak phenol resin. In this case, the heat treatment temperature and time can be appropriately adjusted according to the type and amount of the material used, but the temperature is 10 to 150 ° C., particularly 50 to 100 ° C. higher than the softening point of the non-novolak phenol resin. In 10
It is preferable to melt-mix for 240 minutes, especially 30 to 120 minutes.

The above-mentioned curing agent is suitably used as an epoxy resin composition containing an epoxy resin having two or more epoxy groups in one molecule and an inorganic filler, particularly as a curing agent for an epoxy resin composition for semiconductor encapsulation. can do.

In this case, the epoxy resin (A) may be any resin as long as it has at least two epoxy groups in one molecule. For example, bisphenol A
Type epoxy resin, novolak type epoxy resin, alicyclic epoxy resin, glycidyl type epoxy resin and the like. These epoxy resins can be used alone or in combination of two or more.

Among these epoxy resins, an epoxy resin represented by the following formula is preferred.

[0016]

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Further, as the epoxy resin, a brominated epoxy resin can be used for flame retardation.

The inorganic filler (C) is capable of reducing the expansion coefficient of the sealing material and reducing the stress applied to the semiconductor element, and specifically has a crushed or spherical shape. Fused silica and crystalline silica are mainly used, and alumina, silicon nitride, aluminum nitride and the like can also be used. In the present invention, it is preferable to use a blend of a sphere and a crushed product or only a sphere product as an inorganic filler in order to achieve both low expansion of the cured product and moldability.

It is preferable that the inorganic filler is surface-treated with a silane coupling agent before use.

Further, as the inorganic filler, those having an average particle diameter of 5 to 30 μm are preferably used.

In the epoxy resin composition of the present invention, the curing agent (B) of the present invention is used in an amount of the epoxy resin (A) 1
The range of 5 to 100 parts relative to 00 parts is preferable, and if it is less than 5 parts, sufficient curability may not be provided, and if it exceeds 100 parts, curing is too fast, and when sealing a semiconductor device, In some cases, many internal voids may be generated.

The curing agent (B) of the present invention is a heated mixture of the above non-novolak phenol resin as a curing agent and TPP-K as a curing accelerator, as described above. When the amount of the curing agent is insufficient with only the curing agent for epoxy resin, any conventionally known phenol resin can be used in combination as the curing agent. in this case,
The added amount of the phenolic resin is 0.5 to 2 times the total amount of the phenolic hydroxyl groups of the non-novolak phenolic resin and the optional phenolic resin in the curing agent of the present invention with respect to the epoxy groups of the epoxy resin (A). Mole, especially 0.9
It is preferably in the range of 1.2 to 1.2 times mol.

Further, in the present invention, various conventionally known curing catalysts other than the above-mentioned TPP-K, for example, imidazole or its derivatives, phosphine derivatives, cycloamidine derivatives and the like can be blended.

On the other hand, the compounding amount of the inorganic filler (C) is 2 parts per 100 parts of the total amount of the epoxy resin and all the curing agents.
If the amount is less than 200 parts, the expansion coefficient increases, the stress applied to the semiconductor element increases, and the element characteristics may deteriorate. If the amount exceeds 1200 parts, the viscosity at the time of molding increases. Moldability may deteriorate.

The epoxy resin composition of the present invention preferably contains, in addition to the above-mentioned essential components, a silicone-based flexibility-imparting agent for reducing stress. Examples of the flexibility-imparting agent include silicone rubber powder, silicone gel, and a block polymer of an organic resin and a silicone polymer. Instead of adding such a flexibility-imparting agent, the surface of the inorganic filler may be treated with a two-part type silicone rubber or silicone gel.

The amount of use of the above-mentioned flexibility-imparting agent is preferably 0.5 to 10% by weight, especially 1 to 5% by weight of the whole composition, and if the amount is less than 0.5% by weight. In some cases, sufficient impact resistance may not be given, and if it exceeds 10% by weight, mechanical strength may be insufficient.

The epoxy resin composition of the present invention may further contain, if necessary, other optional components as long as the effects of the present invention are not impaired.

Examples of such optional components include various known thermoplastic resins, release agents such as carnauba wax, higher fatty acids, and synthetic waxes, silane coupling agents, antimony oxide, and phosphorus compounds. .

In the production of the epoxy resin composition of the present invention, predetermined amounts of the above-mentioned components are uniformly stirred and mixed, and the epoxy resin composition is heated by a kneader, roll, extruder or the like which has been heated to 70 to 95 ° C. in advance. It can be obtained by a method such as kneading, cooling and pulverizing. There is no particular limitation on the order of compounding the components.

As described above, the epoxy resin composition of the present invention can be suitably used for encapsulating semiconductor devices such as ICs, LSIs, transistors, thyristors, and diodes, and can be used for manufacturing printed circuit boards. Can be used effectively.

Here, when sealing the semiconductor device,
It can be carried out by employing a molding method conventionally used, for example, transfer molding, injection molding, casting method and the like. In this case, the molding temperature of the epoxy resin composition is 150 to 180 ° C, and the post cure is 150 to 18 ° C.
It is preferably performed at 0 ° C. for 2 to 16 hours.

[0032]

According to the method for producing a curing agent for an epoxy resin of the present invention, when an epoxy resin composition is prepared using this curing agent, storage stability and fluidity are good, and curability, An epoxy resin composition which is excellent in moisture resistance and gives a cured product excellent in adhesiveness can be obtained. Therefore, this epoxy resin composition does not cause a problem associated with thinning of a semiconductor package in recent years, and is useful as a resin for encapsulating a semiconductor. Furthermore, a semiconductor device sealed with a cured product of the composition of the present invention has high reliability.

[0033]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. All parts in each example are parts by weight.

Example 1 As a non-novolak phenol resin, 100 parts of 1,1,3-triphenolpropane (hereinafter referred to as phenol resin I) having a softening point of 110 ° C. and 5 parts of TPP-K were used as a thermometer and a stirrer. Was placed in a 1-liter four-necked flask equipped with the above, left at 150 ° C. for 1 hour, and then mixed at 200 ° C. for 1 hour to obtain a curing agent I.

Example 2 100 parts of a phenol resin represented by the following structural formula and having a softening point of 100 ° C. (manufactured by Mitsui Toatsu Co., Ltd., trade name: DPR1000, hereinafter referred to as phenol resin II) and 5 parts of TPP-K Was placed in the same apparatus as in Example 1 and mixed by heating to obtain a curing agent II.

[0036]

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Comparative Example 1 As a phenol resin, 100 parts of a phenol novolak resin having a softening point of 90 ° C. (hereinafter referred to as phenol resin III) and 5 parts of TPP-K were mixed by heating in the same apparatus as in Example 1, and a curing agent was used. III was obtained.

Examples 3 and 4, Comparative Examples 2 to 5 The epoxy resin, curing agent, curing accelerator and wax E1.
A mixture obtained by adding 5 parts, 500 parts of fused quartz powder and 2 parts of γ-glycidoxypropyltrimethoxysilane was uniformly melt-mixed with a hot two-roll mill to produce an epoxy resin composition.

The following tests (a) to (e) were conducted on these epoxy resin compositions. The results are shown in Tables 1 and 2. (A) Spiral flow 175 ° C, 70k using a mold conforming to EMMI standard
It was measured under the condition of gf / cm ² . (B) Hot hardness: 175 ° C., 70 kgf / cm ² , 60 seconds
The hardness at the time of transfer molding of a rod of × 10 × 4 mm was measured with a Barcol hardness tester. (C) Storage stability The number of days when the spiral flow value became 80% of the initial value when each material was left at 25 ° C. was shown. (D) Tensile adhesive strength A cylindrical molded product having a diameter of 15 mm and a height of 5 mm was molded on a 42 alloy plate under the conditions of 175 ° C., 70 kgf / cm ² and a molding time of 2 minutes, and post-cured at 180 ° C. for 4 hours.
Leave in a constant temperature / humidity bath at 5 ° C / 85% RH for 168 hours,
Further, the tensile adhesive strength after IR reflow deterioration at 240 ° C. was measured. (E) Moisture resistance Evaluation was performed using a 14 PIN DIP type semiconductor device using a test chip having a minimum line width of 1.5 μm and a chip size of 45 mm. Molded at 175 ° C. for 90 seconds, post-cured at 180 ° C. for 4 hours, immersed in a solder bath at 260 ° C. for 10 seconds, and then put in a pressure cooker at 130 ° C. for 1000 seconds.
After leaving for a period of time, the disconnection defective rate of the aluminum wiring was measured.

[0040]

[Table 1]

From the results shown in Table 1, it can be seen that the epoxy resin composition containing the curing agent according to the present invention has good storage stability and fluidity, excellent curability and moisture resistance, and excellent adhesiveness. To give a cured product.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sachi Wakao 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Inside Silicone Electronics Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (72) Inventor Shinichi Jingu Matsui, Usui-gun, Gunma Prefecture Hitomi Tamachi 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Technology Laboratory (56) References JP-A-56-59840 (JP, A) JP-A-56-59841 (JP, A) JP-A Sho 61 -204954 (JP, A) JP-A-61-296019 (JP, A) JP-B-56-45491 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08G 59/40 C08G 59/62 H01L 23/29 C08G 8/28

Claims (3)

(57) [Claims] 1. A phenolic hydroxyl group-containing aromatic group having 3 to 12 carbon atoms and a divalent or tetravalent aliphatic hydrocarbon group bonded to each other, wherein two phenolic hydroxyl groups are contained in one molecule.
A curing agent for an epoxy resin obtained by heating and mixing a non-novolak phenol resin containing at least one non-novolak phenol resin and tetraphenylphosphonium tetraphenyl borate at a temperature equal to or higher than the softening point of the non-novolak phenol resin. 2. An epoxy resin comprising (A) an epoxy resin having two or more epoxy groups in one molecule, (B) a curing agent for the epoxy resin according to claim 1, and (C) an inorganic filler. Composition. 3. A semiconductor device sealed with a cured product of the epoxy resin composition according to claim 2.