JPH062808B2 - Epoxy resin composition for semiconductor encapsulation and semiconductor device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an epoxy resin composition for semiconductor encapsulation that provides a semiconductor device having excellent adhesiveness and moisture resistance, and a semiconductor device encapsulated with the composition. .

[Problems to be Solved by Prior Art and Invention]

In recent semiconductor devices, resin-encapsulation type semiconductors, which are excellent in mass productivity and can be manufactured at low cost, are increasing in number as compared with conventional ceramic and can-encapsulation type devices.

As this sealing resin, the use of epoxy resin, which is excellent in electrical properties and mechanical properties, is increasing.

However, a semiconductor device sealed with a resin typified by an epoxy resin has hygroscopicity as compared with a ceramic or can-sealing type device, and water does not enter through an interface between the resin and the frame. It has a problem of many.

In addition, ionic impurities such as hydrolyzable Cl remain in the sealing resin, and these increase the leak current of the semiconductor device and the corrosion of the aluminum electrode due to the interaction with water. It is a cause of a large decrease in reliability.

Therefore, various improvements have been attempted for the purpose of preventing defects due to the above-mentioned insufficient moisture resistance of the semiconductor device sealed with the epoxy resin. For example, it has been proposed to remove ionic impurities in the encapsulating material or to add an additive that traps ionic substances, but these also completely or surely remove or trap ionic substances. It is virtually impossible to do so, and there is a disadvantage that the intended purpose cannot be achieved. It is also known to mix a silane coupling agent in order to improve the moisture resistance of the encapsulating material, and as the silane coupling agent of the epoxy resin composition for encapsulating a semiconductor device, an epoxy-based silane or a mercapto-based silane coupling agent is used. Silane, amine-based silane, unsaturated hydrocarbon-based silane, etc. are used.

In this case, for example, 3-mercaptopropyltrimethoxysilane is used as the mercapto-based silane, but this has a bad odor and is problematic in practical use.
For example, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane is used as the amine-based silane, but a composition containing this has the disadvantage of extremely poor storage stability. Further, as the unsaturated hydrocarbon-based silane, for example, vinyltriethoxysilane and 3-methacryloxypropyltrimethoxysilane are used, but they do not have a functional group that reacts with the phenol-curable epoxy resin, and therefore, the cup It is difficult to fully exhibit the function as a ring agent.

On the other hand, as the epoxy-based silane, for example, 3-glycidoxypropyltrimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane are used. sex,
There is a problem that the moisture resistance is not sufficient.

The present invention has been made in view of the above circumstances, and has adhesiveness,
An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation excellent in moisture resistance, particularly moisture resistance after moisture absorption soldering, and a semiconductor device encapsulated with a cured product of the composition.

[Means and Actions for Solving the Problems]

The present inventor has conducted extensive studies in order to achieve the above-mentioned object, and as a coupling agent, an epoxy resin, a substituted or unsubstituted novolac-type phenol resin, and an epoxy resin composition containing an inorganic filler as a main component are shown below. General formula
(1) (However, Y is a same or different group selected from a methoxy group, an ethoxy group, a propenoxy group, a methyl group, and an ethyl group, but at least one is a methoxy group, an ethoxy group, or a propenoxy group. , M are integers of 1 to 3, 1 + m = 4, and n is an integer of 2 to 10). 1 to 0: 1 by weight ratio of silane and γ-glycidoxypropyltrimethoxysilane. 5, and preferably water and 1,8-diazabicyclo (5.4.0) undecene-7 are added to the epoxy resin composition at a ratio of 1: 0.1 to 1: 2. DI
It is effective for encapsulation of any type of semiconductor device of P type, QFP type, SOJ type, SOP type, PLCC type, and the encapsulated semiconductor device has adhesiveness, moisture resistance, especially moisture resistance in the soldering process after moisture absorption. It has been found that it is extremely excellent in sex.

That is, the silane represented by the general formula (1) and γ-glycidoxypropyltrimethoxysilane are known as silane coupling agents, and the silane represented by the general formula (1) is particularly an ether in the alkylene chain. Since it does not contain volatile oxygen, it has excellent water repellency and low ionic impurities. For example, the electric conductivity of the liquid extracted by immersing for 2 hours in a sample volume of 10 g / H ₂ O 30 ml is 2 μs / c.
It has m and pH of 5.9, which is significantly superior to γ-glycidoxypropyltrimethoxysilane of 15 μs / cm, 3.5. Therefore, when used in an epoxy resin composition, it has excellent moisture resistance. Although the composition is obtained,
On the other hand, it has the drawback that the adhesive strength to the frame and silicon chip is not sufficient. On the other hand, γ-glycidoxypropyltrimethoxysilane is added to the silane represented by the general formula (1), and water and 1,8-diazabicyclo (5.4.0) undecene-7 (hereinafter, It has been found that the combined use of (abbreviated as DBU) improves the adhesive strength by these synergistic effects, and that excellent moisture resistance is maintained, and the present invention has been completed.

Therefore, the present invention provides an epoxy resin, a substituted or unsubstituted novolac type phenol resin and an epoxy resin containing an inorganic filler as a main component, and a silane represented by the above general formula (1) and γ-glycidoxy as a coupling agent. An epoxy resin composition for semiconductor encapsulation, which comprises a specific amount of water and DBU together with propyltrimethoxysilane in the above proportion, and a semiconductor device encapsulated by a cured product of the composition. provide.

Hereinafter, the present invention will be described in more detail.

The epoxy resin composition for semiconductor encapsulation of the present invention is an epoxy resin, a substituted or unsubstituted novolac type phenol resin,
It contains an inorganic filler.

Here, as the epoxy resin, as long as it can be cured by a novolac type phenol resin described later,
The molecular structure, molecular weight, etc. are not particularly limited, and various conventionally known compounds can be used. For example, an epoxy resin synthesized from various novolac resins including epichlorohydrin and bisphenol, an alicyclic epoxy resin, and an epoxy resin obtained by introducing a halogen atom such as chlorine or bromine into these can be mentioned. Novolak and epoxidized phenol novolac are preferably used. For example, the following general formula (However, in the formula, R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, x is 1, 2, or 3, and y is an integer of 0 to 10.) can be used. .

Next, a substituted or unsubstituted novolac type phenolic resin,
It is used as a curing agent for the above epoxy resin, and specifically, the following compounds are exemplified.

(However, in the formula, p represents a positive number of 2 to 15, and q, r
Is a positive number such that q + r = 2 to 15. ) The above novolac phenolic resins can be used alone or in combination of two or more.

Further, as the inorganic filler, those commonly used in epoxy resins for semiconductor encapsulation can be used, but among them, quartz powder is typical. As the quartz powder, crystalline silica, fused silica, or the like can be used, and the shape thereof may be any of a crushed product, a spherical product, and a fine powder having a particle size of 1 μm or less, but a particle size of 75 μm or more for preventing local stress applied to a semiconductor element. The coarse powder is preferably 0.3% by weight or less based on the whole quartz powder. Further, in order to improve the fluidity of the composition, it is desirable to use spherical silica having an average particle diameter of 0.4 to 2 μm in an amount of 5 to 20 parts by weight based on 100 parts by weight of all quartz powder.

In addition, depending on the use, purpose, etc. of the composition according to the present invention, fillers other than silica-based ones can be used, for example, talc, mica, clay, kaolin, calcium carbonate, alumina, zinc white, baryta, Glass balloons, glass fibers, aluminum hydroxide, calcium hydroxide, asbestos, titanium oxide, iron oxide, silicon nitride and the like can be used.

These inorganic fillers are used alone or in combination of two or more, and the total amount of the epoxy resin and the substituted or unsubstituted novolac type phenolic resin described above is 250 to 600 parts by weight, particularly 350 to 100 parts by weight. It is preferably used in the range of 550 parts by weight. If the amount used is more than this range, not only the dispersion becomes difficult, but also the physical properties such as workability, low stress, and crack resistance become disadvantageous, while if the amount used is too small, the expansion coefficient may increase.

Further, the coupling agent used as an essential component of the epoxy resin composition of the present invention, the following general formula (1) (However, Y is a same or different group selected from a methoxy group, an ethoxy group, a propenoxy group, a methyl group, and an ethyl group, but at least one is a methoxy group, an ethoxy group, or a propenoxy group. , M are each an integer of 1 to 3, 1 + m = 4, and n is an integer of 2 to 10.) 1: 0 to 1: 5 from silane and γ-glycidoxypropyltrimethoxysilane Preferably 1:
It is used in combination at a weight ratio of 0.1 to 1: 2, more preferably 1: 0.2 to 1: 1 and further added with water and DBU.

Specific examples of the silane represented by the general formula (1) include the following.

(However, a and b are integers of 0 to 3, respectively, and a + b = 3). Commercially available Prosil 2210
(Manufactured by SCM).

The compounding ratio of the silane represented by the general formula (1) and γ-glycidoxypropyltrimethoxysilane is 1: 0 to 1: 5 by weight, preferably 1: 0.
The ratio is 1 to 1: 2, and more preferably 1: 0.2 to 1: 1, whereby an epoxy resin having excellent adhesiveness and moisture resistance can be provided.

In the present invention, water and DBU are added to promote the action of the silane coupling agent. In this case, the silane represented by the general formula (1) and γ-glycidoxypropyltrimethoxysilane are added. The amount of water added is 10 parts by weight or less, preferably 3 to 8 parts by weight, and DBU is 2 parts by weight or less, preferably 0.5 to 1 part by weight, based on 100 parts by weight.

The above-mentioned silane coupling agent and water according to the present invention, D
BU is 0.05 to 10 parts by weight, particularly 0.5 to 3 parts by weight, based on 100 parts by weight of the total amount of the epoxy resin, the substituted or unsubstituted phenol novolac resin and the inorganic filler described above. It is preferable to mix them as follows. If the blending amount is less than 0.05 parts by weight, the effect of improving the moisture resistance is not seen so much, while if it exceeds 10 parts by weight, the glass transition point of the cured product becomes low and exudation to the surface of the cured product is observed. May be.

The method of adding the coupling agent (the above-mentioned silane coupling agent, water, DBU) according to the present invention is not particularly limited, and for example, an integral blend, a method of adhering it to the surface of the inorganic filler, or the like can be adopted.

In the present invention, various curing accelerators such as imidazole or a derivative thereof, a tertiary amine-based derivative, a phosphine-based derivative, and a cyclohexyl derivative for the purpose of accelerating the reaction between the above-mentioned epoxy resin and a substituted or unsubstituted phenol novolac resin. There is no problem in using an amidine derivative or the like in combination, but it is preferable to use a curing catalyst containing DBU and triphenylphosphine in a weight ratio of 0: 1 to 1: 1.

Further, it is desirable to add an organopolysiloxane compound to the composition of the present invention in order to impart flexibility.
Examples of the organopolysiloxane compound include silicone oils having an epoxy group, an amino group, a hydroxyl group, etc.
Examples thereof include silicone rubber and curable silicone rubber. Particularly, alkenyl group-containing novolac resin and the following general formula (In the formula, R ′ represents a monovalent organic group. Further, c is 0.001 ≦ c ≦ 1, d is 1 ≦ d ≦ 3, 1.001 ≦ c.
+ D ≦ 3. The block copolymer obtained by the addition reaction with the organopolysiloxane represented by (4) is preferable. As the block copolymer of the alkenyl group-containing novolak resin and the organopolysiloxane, those described in JP-A-63-226951 can be adopted. In this case, the compounding amount of the block copolymer is 2-1 per 100 parts by weight of the total amount of the epoxy resin and the substituted or unsubstituted phenol novolac resin.
It is preferably in the range of 00 parts by weight. When the amount of the block copolymer used is less than 2 parts by weight, the effect of improving crack resistance may not be sufficiently achieved, and 1
If it exceeds 100 parts by weight, the mechanical strength may decrease.

The ratio of the amount of epoxy groups (emol) to the amount of phenolic hydroxyl groups (fmol) contained in the epoxy resin, the substituted or unsubstituted phenol novolac resin and the block copolymer is e / f = 0.5 to 1 It is desirable to be in the range of 0.5, and if e / f is out of the above range, it may be disadvantageous in physical properties such as curability and low stress.

If desired, various additives can be added to the composition of the present invention. For example, one or two of waxes, releasing agents such as fatty acids such as stearic acid and metal salts thereof, pigments such as carbon black, flame retardants, and other additives.
More than one species can be blended.

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 70 to 95 is prepared in advance.
It can be obtained by a method such as kneading with a kneader, roll, extruder or the like heated to ℃, cooling and pulverizing. Here, there is no particular limitation on the order of mixing the components.

The composition of the present invention thus obtained can be effectively used for encapsulating a semiconductor device such as a DIP type, a flat pack type, a PLCC type, and an SO type. In this case, the molding is performed by a conventionally adopted molding method, for example, It can be performed by adopting transfer molding, injection molding, casting method or the like.
The molding temperature of the epoxy resin composition is 150 to 180.
The post-curing is preferably performed at 150 to 180 ° C. for 2 to 16 hours.

〔The invention's effect〕

As explained above, the epoxy resin composition of the present invention,
By incorporating the above-mentioned coupling agent, the adhesiveness to the frame and the silicon chip is excellent, and the moisture resistance, especially the moisture resistance after moisture absorption soldering is good. Therefore, sealing with the cured product of the epoxy resin composition of the present invention The manufactured semiconductor device has excellent reliability.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

In the following examples, all parts are parts by weight.

[Examples 1 to 11 and Comparative Examples 1 to 4] The components shown in Table 1 were uniformly melt-mixed with a hot double roll, cooled and pulverized to obtain an epoxy resin composition.

The following tests (a) to (g) were conducted on these compositions. The results are also shown in Table 1.

(A) Spiral flow value Using a mold conforming to the EMMI standard, 180 ° C, 70
It was measured under the condition of kg / cm ² .

(B) Mechanical strength (flexural strength and flexural modulus) 180 ° C., 70 kg / cm ² , according to JIS-K6911
Measurement was performed on a 10 × 4 × 100 mm bending bar molded under the condition of a molding time of 2 minutes and post-cured at 180 ° C. for 4 hours.

(C) Expansion coefficient, glass transition temperature Using a test piece of 4 mmφ × 15 mm, the value when the temperature was raised at a rate of 5 ° C./min was measured by a dilatometer.

(D) Adhesiveness (I) The package shown in the drawing is molded under molding conditions of 175 ° C. × 2 minutes, post-cured at 180 ° C. for 4 hours, and then the frame (material: 42 alloy, thickness: 0.25 mm) is pulled out. The force was measured.

In the drawings, 1 is a frame and 2 is a sealing resin. The dimensions are mm.

(E) Moisture resistance (I) A silicon chip with a size of 9.0 × 4.5 × 0.5 mm is adhered to a PLC frame of 20 PIN, and the epoxy resin composition is molded under the condition of 180 ° C. × 2 minutes. , 180
Post cure at 4 ° C for 4 hours.

This is left in an atmosphere of 85 ° C / 85% RH for 72 hours, then immersed in a solder bath at a temperature of 260 ° C, and then 130 ° C.
/ Allow 100 hours after leaving in the atmosphere of 85% RH
The corrosion incidence was measured. The pattern width of Al is 5μ.
m.

(F) Moisture resistance (II) A silicon chip with a size of 8.0 × 10.0 × 0.5 mm is adhered to a flat package with a size of 10 × 14 × 2.3 mm, and an epoxy resin composition is applied to this. Molding condition 180
It was molded at ℃ × 2 minutes and post-cured at 180 ℃ for 4 hours.

This was left in an atmosphere of 85 ° C / 85% RH for 48 hours, then immersed in a solder bath at a temperature of 260 ° C, and then 121 ° C.
/ 100% RH, 100 hours after leaving
l Corrosion incidence was measured. The pattern width of Al is 5
μm.

(G) Adhesiveness (II) A silicon chip having a size of 9.0 × 4.5 × 0.5 mm is adhered to a 14PIN-IC frame (42 alloy), and an epoxy resin composition is formed thereon under a molding condition of 180 ° C. × Molded in 2 minutes and post-cured at 180 ° C for 4 hours, then 121
The sample was left to stand in an atmosphere of ° C / 100% RH for 24 hours, and then immersed in solder at 215 ° C / 30 seconds.

About this, the adhesiveness of the interface between the chip and the sealing material was examined with an ultrasonic flaw detector (Hitachi AT5000), and evaluated according to the following criteria.

○: Very good △: Good ×: Poor (1) Epoxy Resin (I) EOCN1020-70 (Nippon Kayaku) Epoxy Equivalent 196 (2) Epoxy Resin (II) EPPN501H (Nippon Kayaku) Epoxy Equivalent 162 (3) Br Epoxy Resin BREN-S (Japan Kayaku) Epoxy equivalent 280 (4) Phenol novolac resin KH3488 (Dainippon Ink and Chemicals) Phenol equivalent 11
0 (5) Block copolymer When Addition reaction product with [epoxy equivalent 305, organopolysiloxane 34
% By weight] (However, the subscripts in the formula indicate average values.) (6) Quartz powder (I) Silica having an average particle size of 12 μm and a particle size of 75 μm or more and a content of 0.1% by weight.

(7) Quartz powder (II) Silica having an average particle size of 0.5 μm and a specific surface area of 6 m ² / g.

(8) Coupling agent (I) Prosil 2210 (manufactured by SCM) (9) Coupling agent (II) (10) Coupling agent (III) (11) γ-glycidoxypropyltrimethoxysilane
KBM403E (manufactured by Shin-Etsu Chemical Co., Ltd.)

BRIEF DESCRIPTION OF THE DRAWINGS The drawing is a perspective view showing a package used in the adhesion (I) test.

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Claims (2)

[Claims] 1. An epoxy resin composition comprising an epoxy resin, a substituted or unsubstituted novolac type phenol resin and an inorganic filler as main components, wherein the following general formula (1) (However, Y is a same or different group selected from a methoxy group, an ethoxy group, a propenoxy group, a methyl group, and an ethyl group, but at least one is a methoxy group, an ethoxy group, or a propenoxy group. , M are integers of 1 to 3, 1 + m = 4, and n is an integer of 2 to 10). 1 to 0: 1 by weight ratio of silane and γ-glycidoxypropyltrimethoxysilane. 5 parts, and water in an amount of 10 parts by weight or less based on 100 parts by weight of the total amount of both silanes, and 1,8-diazabicyclo (5.4.0) undecene-7 was added to the total amount of both silanes. An epoxy resin composition for semiconductor encapsulation, which is compounded in a proportion of 2 parts by weight or less with respect to 100 parts by weight. 2. A semiconductor device encapsulated with a cured product of the epoxy resin composition for semiconductor encapsulation according to claim 1.