JP2938158B2 - Epoxy resin composition for semiconductor encapsulation - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an epoxy resin composition used as a semiconductor sealing material.

[Conventional technology]

Epoxy resin compositions containing polyfunctional epoxy compounds, phenol novolak-based curing agents, curing accelerators, and inorganic fillers as main components have been recognized to have excellent performance, and in recent years semiconductor encapsulants, which have been growing remarkably, Widely used as.

However, with the increasing integration and size of semiconductors and changes in the method of mounting semiconductors on substrates, performances such as low stress resistance and solder crack resistance are strongly required. This is one of the causes of defects such as cracks in semiconductors and devices using them without solder cracks and thermal shock.

As a method for solving this problem, it has been proposed to add a block copolymer comprising an alkenyl group-containing aromatic polymer and an organopolysiloxane to a curable epoxy resin (JP-A-58-21417). Gazette), but it is difficult to control the domain size in this block copolymer, so that the thermal shock resistance in the heat cycle test,
Insufficient solder cracking resistance, increased burr,
There has been a strong demand for improvements in moldability, such as poor sealability.

In order to solve these problems, a combination of an organopolysiloxane and a copolymer of an aromatic hydrocarbon and an organopolysiloxane (JP-A-61-271319) has been proposed. Poor moldability due to exudation of the organopolysiloxane later, poor storage at high temperature, etc. occur.

It has also been proposed to blend a copolymer of a combination of a short-chain organopolysiloxane and a long-chain organopolysiloxane with an alkenyl group-containing epoxy resin (JP-A-63-238123). In this case, too, it was found that poor moldability was caused by exudation of low molecular weight components based on the short chain length organopolysiloxane.

[Problems to be solved by the invention]

The present invention solves the above-mentioned drawbacks, and provides an epoxy resin composition for semiconductor encapsulation which is excellent in thermal shock resistance and solder crack resistance, does not deteriorate mechanical properties, and is excellent in moldability and high-temperature storage property. It is in.

[Means for solving the problem]

The Si—H group-containing organopolysiloxane-modified polyfunctional epoxy resin constituting the present invention has the following formula (I) (However, in the formula, R ₁ is a polyfunctional epoxy resin, and R ₂ has 1 to 1 carbon atoms.
3 alkyl groups or phenyl groups, 1, m and n
Is (1 + m + n) from 15 to 200, m is 0 to 20, n is 2 to 5
It satisfies 0. ). The polyfunctional epoxy resin of R _1, for example, cresol novolak epoxy resins, phenol novolak epoxy resins, alicyclic epoxy resins, bisphenol A novolac epoxy resin, bromide bisphenol A novolac epoxy resins,
Although various types of polyfunctional resins may be mentioned, the structure is not necessarily limited to only one type of structure, and may be a mixture of two or more types. Among these polyfunctional epoxy resins, those obtained by removing ionic impurities such as Na ⁺ and Cl ⁻ at an epoxy equivalent of 150 to 250 and a softening point of 60 to 130 ° C. as much as possible are preferable. R ₂ includes a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a phenyl group and the like, and is not limited to one kind of structure, but a methyl group is preferable for reducing stress. 1, m, n
It is necessary that (1 + m + n) is 15 to 200, preferably 30 to 100, m is 0 to 20, preferably 0 to 10, and n is 2 to 50, preferably 4 to 30. If these ranges are exceeded, the glass transition point is reduced and the burrs are increased due to the miniaturization of the sea-island structure, or the bending strength is reduced due to the phase separation due to the weakening of the interface between the formed domain and the matrix, Various problems such as a decrease in Barcol hardness, a decrease in printability, and a problem in synthesis occur, and the object of the present invention cannot be achieved. Further, the alkenyl group-containing low molecular weight epoxy compound and the alkenyl group-containing low molecular weight phenol compound to be added to the organopolysiloxane-modified polyfunctional epoxy resin having a Si-H group have a mole number (a) of the alkenyl group-containing low molecular weight epoxy compound. Number of moles of alkenyl group-containing low molecular weight phenol compound (b)
Is (a) / (b) = 0.1 to 10, preferably 0.6 to 1.
5 and the formula (I)
The total of the number of moles of alkenyl groups of the alkenyl group-containing low molecular weight epoxy compound and the alkenyl group-containing low molecular weight phenol compound is at least 4 mol% with respect to the number of moles of Si-H groups in the -H group-containing organopolysiloxane-modified epoxy resin. It is necessary to add them so that Exceeding these ranges may cause exudation of the silicone component during molding and failure during storage at high temperatures. These alkenyl group-containing low molecular weight epoxy compounds and alkenyl group-containing low molecular weight phenol compounds can be introduced into the Si-H group-containing organopolysiloxane-modified polyfunctional epoxy resin by a hydrosilylation reaction using a known platinum catalyst. I can do it. Specifically, examples of the alkenyl group-containing low molecular weight epoxy compound include allyl glycidyl ether, allyl phenyl glycidyl ether, allyl bisphenol A
Epoxy and the like, and alkenyl group-containing low molecular weight phenol compounds include 2-allylphenol, 4-eugenol, and allylbisphenol A.

Next, as the polyfunctional epoxy resin constituting the present invention,
For example, various types of polyfunctional epoxy resins, such as cresol novolak epoxy resin, phenol novolak epoxy resin, alicyclic epoxy resin, bisphenol A novolak epoxy resin, and bisphenol A novolak epoxy resin, may be used. However, the use is not necessarily limited to the use of only one kind, and two or more kinds may be used in combination. Among these polyfunctional epoxy resins, those obtained by removing ionic impurities such as Na ⁺ and Cl ⁻ at an epoxy equivalent of 150 to 250 and a softening point of 60 to 130 ° C. as much as possible are preferable.
Next, as the phenol novolak-based curing agent constituting the present invention, for example, phenol novolak, cresol novolak, xylenol novolak, bisphenol A
Novolak, resorcinol novolak resin and the like can be mentioned, but the use thereof is not necessarily limited to the use of only one kind, and two or more kinds may be used in combination. Among these phenol novolak-based curing agents, OH equivalent is 80 to 150, and softening point is 60 to 120 ° C.
It is preferable to remove ionic impurities such as ⁺ and Cl ⁻ as much as possible.

Further, imidazole or a derivative thereof, a tertiary amine derivative, a phosphine derivative, a cycloamidine derivative, or the like is used as a curing accelerator for the purpose of accelerating the reaction between the polyfunctional epoxy resin and the phenol novolak resin.

Examples of the inorganic filler include crystalline silica, fused silica, alumina, calcium carbonate, talc, mica, glass fiber, and the like. These may be used alone or as a mixture of two or more.

In the composition of the present invention, other additives as required, for example, release agents such as natural waxes and synthetic waxes, flame retardants such as hexabromobenzene, decabromobiphenyl ether, antimony trioxide, Colorants such as carbon black and red iron oxide, silane coupling agents, other synthetic rubbers, silicone compounds, thermoplastic resins and the like may be appropriately compounded. After sufficiently mixing the above-mentioned compound with a mixer or the like, the mixture is further melted and mixed by heating with a kneader or a roll, and then cooled and solidified, and then pulverized to obtain the epoxy resin composition for semiconductor encapsulation of the present invention.

[Action]

In the present invention, the epoxy group and the phenol group introduced into the organopolysiloxane component improve the dispersibility, improve the interface between the domain in the sea-island structure and the matrix, and further introduce the above-mentioned component in the silicone domain that has aggregated during the curing process. By giving a cross-linked structure inside the domain by the reaction between the epoxy group and the phenol group, the silicone component exudes to the surface of the molded product, and hardening such as preventing defects during high-temperature storage is developed.

〔Example〕

(Reference Example (1)) First, a production example of an organopolysiloxane-modified polyfunctional epoxy resin constituting the present invention will be described.

In a 1-liter four-necked flask, an organopolysiloxane component represented by the following formula (A) having a content of 16.7% by weight
After putting 120 g of an organopolysiloxane-modified epoxy resin containing -H group (abbreviated as Si-Ep) and 440 g of toluene, attaching a reflux condenser and a dropping funnel, and performing azeotropic dehydration for 1 hour, the temperature in the system is lowered. Bring to 90 ° C. Then add 0.5 g of a 1% solution of chloroplatinic acid in isopropanol,
The amount of allyl glycidyl ether shown in Table 1 (AGE
) And 2-allylphenol (abbreviated as 2-AP), and allowed to react for 3 hours. Then, the solvent was distilled off under reduced pressure to obtain an organopolysiloxane-modified polyfunctional epoxy resin.

(Reference Examples (2) to (6)) Si-Ep was replaced with the following formulas (B) to (F), and AGE, 2-AP
Was changed to the amount shown in Table 1, and the same procedure as in Reference Example (1) was performed to obtain an organopolysiloxane-modified polyfunctional epoxy resin.

(Note) In the formula, R is an orthocresol novolak epoxy resin.

Examples [1 to 4] 70 parts by weight of an organopolysiloxane-modified polyfunctional epoxy resin synthesized based on Reference Examples (1) to (4) and 30 parts by weight of a cresol novolak epoxy resin (epoxy equivalent 200, softening point 62 ° C.) , Phenol novolak resin (OH equivalent
105, softening point 100 ° C) 40 parts by weight, brominated phenol novolak epoxy resin (bromine content 30% by weight, epoxy equivalent
280, softening point 71 ° C) 10 parts by weight, fused silica 530 parts by weight, antimony trioxide 20 parts by weight, silane coupling agent 3 parts by weight, triphenylphosphine 4 parts by weight, carnauba wax 5 parts by weight, carbon black 5 parts by weight And kneaded at 95 to 100 ° C., cooled, pulverized, and made into tablets to produce four types of epoxy resin compositions for semiconductor encapsulation of the present invention.

Comparative Examples [1-2] Two types of epoxy resin compositions were produced using the organopolysiloxane-modified epoxy resin synthesized based on Reference Examples (5) and (6) in the same manner as in the Examples.

The stain resistance, resin burr, etc. of the epoxy resin compositions produced as these Examples and Comparative Examples were determined using a transfer molding machine (molding conditions: mold temperature: 175 ° C., curing time: 2 minutes) and obtained. The molded product was cured at 175 ° C. for 4 hours, and the sealability, thermal shock resistance, solder resistance, mechanical strength, and the like of the package were evaluated by various tests (A) to (K). Table 2 shows the evaluation results.

(A) Spiral flow value A spiral flow value was measured at a molding temperature of 175 ° C. and a molding pressure of 70 kg / cm ² using a mold conforming to the EMMI standard.

(A) Burr After molding, the length of the resin burr at the vent portion was measured.

(C) Barcol hardness Molding was performed at a molding temperature of 175 ° C., a molding pressure of 70 kg / cm ² , and a molding time of 2 minutes.

(D) Moldability The number of molding shots before the occurrence of mold fogging was evaluated as ○ for 2000 or more, × for 1000 or more, and Δ for 1000 to 2000.

(E) Stamping property The molded article of the 10th shot was used, and it was evaluated whether or not the stamping was peeled off with a cellophane tape after stamping. Those that did not peel off were represented by 、, those that peeled off were represented by x, and the middle was represented by Δ.

(F) Mechanical strength (flexural modulus, flexural strength) Molding temperature 175 ° C, molding pressure 70Kg / cm according to JIS-K6911
^2. Measurement was performed on a molded article having a molding time of 2 minutes and post-curing at 175 ° C. for 4 hours.

(G) Glass transition point The value when the temperature was increased at a rate of 5 ° C. per minute by a dilatometer was measured.

(H) Thermal shock resistance Molding temperature: 175 ° C, molding pressure: 70 kg / cm ² , molding time: 2 minutes, post-curing at 175 ° C, 8 hours, -65 ° C x 15 minutes, 1
A heat cycle of 50 ° C. × 15 minutes was repeated, and the rate of occurrence of resin cracks after 1000 cycles was measured.

(G) Solder resistance Molding temperature: 175 ° C, molding pressure: 70 kg / cm ² , molding time: 2 minutes, post-curing at 175 ° C, 8 hours, and after treatment at 85 ° C, 85% steam for 144 hours. The resin was immersed in a 260 ° C. solder bath for 10 seconds, and the rate of occurrence of resin cracks was measured.

(G) High-temperature storage characteristics The weight loss rate (%) of a 100 mm × 10 mm × 4 mm test piece when stored at 200 ° C. for 1000 hours was measured.

〔The invention's effect〕

The present invention relates to an organopolysiloxane-modified polyfunctional epoxy resin obtained by adding an alkenyl group-containing epoxy compound and an alkenyl group-containing phenol compound to an organopolysiloxane-modified polyfunctional epoxy resin having a Si-H group. An epoxy resin composition for semiconductor encapsulation that has the effects of thermal shock resistance and solder cracking resistance, and is excellent in moldability and high-temperature storage properties by being blended with a system curing agent, curing accelerator, and inorganic filler. Was.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ identification code FI H01L 23/31 (58) Fields investigated (Int.Cl. ⁶ , DB name) C08G 59/14 C08G 59/62 C08L 63/00 -63/10 H01L 23/29

Claims (1)

(57) [Claims] (A) An organopolysiloxane-modified polyfunctional epoxy resin containing a Si—H group represented by the following formula (I): (However, in the formula, R ₁ is a polyfunctional epoxy resin, and R ₂ has 1 to 1 carbon atoms.
3 alkyl groups or phenyl groups, 1, m and n
Is such that (1 + m + n) is 15 to 200, m satisfies 0 to 20, and n satisfies 2 to 50. )) A low molecular weight epoxy compound containing an alkenyl group in the Si-H group and a low molecular weight phenol compound containing an alkenyl group, and a mole number (a) of the alkenyl group containing low molecular weight epoxy compound and The number of moles (b) is the ratio of (a) / (b) = 0.1 to 10 and the number of moles of Si—H groups in the Si—H group-containing organopolysiloxane-modified epoxy resin represented by the formula (I) On the other hand, the total number of moles of alkenyl groups of the alkenyl group-containing low molecular weight epoxy compound and the alkenyl group-containing low molecular weight phenol compound is 4 mol%.
(B) a polyfunctional epoxy compound, (C) a phenol novolak-based curing agent, (D) a curing accelerator, and (E) an inorganic filler. Epoxy resin composition for semiconductor encapsulation.