JPH01126361A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition giving a semiconductor sealant having remarkably decreased internal stress and excellent moisture resistance, moldability, printability and adhesivity to carrier tape, by compounding a silicone resin with an epoxy resin, a phenolic resin and an inorganic filler. CONSTITUTION:The objective composition is produced by compounding (A) a silicone-modified resin produced by dispersing at least two kinds of silicone oils having mutually reactive functional groups in a phenolic resin or an epoxy resin in the form of oil droplets using a dispersing agent, (B) an epoxy resin, (C) a phenolic resin and (D) an inorganic filler. The mixing ratio of the silicone coils of the component A is preferably selected to give a ratio of the numbers of the reactive functional groups of the resin and the oil of preferably close to 1:1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an epoxy resin composition for encapsulating semiconductors that is particularly excellent in encapsulating electronic components such as semiconductors.

(Prior art) In recent years, most of the encapsulation of semiconductors (hereinafter referred to as ICs) has been performed using resin to soil, and epoxy resin compositions have become mainstream in terms of adhesiveness with elements and cost. It has become. These require technical improvements necessary to maintain characteristic 2 of semiconductors. Among these, two important issues are improving moisture resistance reliability and reducing internal stress generated from distortion caused by curing shrinkage of the resin and the difference in coefficient of thermal expansion between the resin and the element.

In particular, due to the recent increase in the integration of ICs, the size of devices has increased, and cracks in the resin due to internal stress and internal stress during thermal shock have become a major problem.

For this reason, various studies have recently been conducted with the aim of reducing this internal stress, and methods for reducing internal stress include: - lowering the coefficient of thermal expansion of the resin to be close to that of the element; ■ increasing the modulus of elasticity. Examples include lowering.

The former is generally an inorganic photoresist with a small coefficient of thermal expansion.
However, since the shape of these fillers usually has a substantially fractured surface, if they are highly filled, WAr will occur during which poor moldability and flowability will occur. The latter is achieved by adding a toughness imparting agent to the resin. To this, powder of butadiene-based or silicone-based PUM or powder of silicone resin may be added (Japanese Patent Laid-Open No. 54
No. 54168, Japanese Unexamined Patent Publication No. 61-283649), it has been considered to add silicone oil having a functional group reactive with resin. In particular, it is known that when dispersed in micron units in a reactive silicone oil mixture, it exhibits excellent properties such as low stress and thermal shock resistance.

However, since the inside of these dispersed dangerous silicone oils does not react with the resin, unreacted silicone oil oozes out during molding, causing mold stains, and
Silicone oil that has seeped out on the surface of the molded product causes various problems, such as a decrease in the marking performance of the marking ink and a lack of adhesion with the tape used to transport the IC package.

On the other hand, there are methods to reduce unreacted substances by reacting the resin with silicone oil in advance (Unexamined Japanese Patent Publication No. 5
9-18724 Publication No. 1 weighing), and a study to improve the compatibility between silicone oil and resin and the dispersion stability of silicone oil by adding a dispersant for silicone oil to this system (Japanese Patent Laid-Open No. 124116/1983) However, no significant effect has been obtained on the seepage of unreacted substances.

Mayu silicone oil t Oh, let's make it sticky ρλ
There is also consideration of adding
(No. Publication) This does not allow for dispersion in micron units, and it is not possible to significantly improve low stress properties or thermal shock resistance.

(Problems to be Solved by the Invention) The present invention solves these drawbacks, and uses silicone oil, a specific silicone compound, and a phenol resin or epoxy resin as a dispersant. By incorporating into the epoxy resin composition,
An epoxy resin composition for semiconductor encapsulation that significantly reduces the internal stress of the encapsulation material, has excellent moisture resistance, and has good moldability against mold stains, imprintability, and adhesion to IC package transportation tapes. This is what we are trying to provide.

(Means to Solve Problem R) That is, the present invention has the following features: (&) At least two types of silicone oils having functional groups that can react with each other are dispersed as oil droplets in a phenol resin or an epoxy resin using a dispersant. , an epoxy resin composition comprising: a silicone modified resin obtained by subjecting the silicone oil to a crosslinking reaction within oil droplets; ('0) an epoxy resin; (c) a phenol resin; and (a) an inorganic filler. be.

The present invention will be explained in detail below.

The silicone-modified resin of the present invention refers to silicone oil that is dispersed in a phenol resin or epoxy resin with a silicone oil mixture and a t-dispersant, and then the silicone oil is dispersed in oil droplets in the phenol resin or epoxy resin. The modified resin and phenol resin or epoxy resin subjected to a crosslinking reaction are reacted with silicone oil, and the silicone oil is crosslinked with each other in the oil boundary in the resin in the same manner as above to form a specific modified resin, and any of the mixtures of the above 2's. You can also make one.

The silicone oil used in the silicone-modified resin of the present invention includes a functional group that reacts with a phenol resin or an epoxy resin, and a functional group that reacts with each other in the silicone oil. A mixture of at least 21 m groups of polydimethylsiloxane having a pendant shape or having reactive functional groups bonded to both ends of the polydimethylsiloxane, or one obtained by replacing the methyl group with a phenyl group or hydrogen. . These functional groups are
There is no particular restriction as long as the assembly can react with a phenol resin or an epoxy resin and react with each other and crosslink, but preferably an epoxy group and an amino group,
Examples include combinations of silicone oils having epoxy groups and carboxyl groups, hydrogen and vinyl groups, epoxy groups and mercapto groups, and evo-Φ groups and hydroxyl groups.

The mixing ratio of these silicone oils is based on the stoichiometric amount of functional groups that can react with each other with the phenol resin or epoxy resin and the silicone oil. It is preferable that the ratio be close to 1:1, and it becomes difficult to crosslink the two extremes.

The functional group equivalents and molecule 'i of these silicone oils are
It is necessary that appropriate cross-linking between silicone oils occurs at least within the oil cylinder in the silicone-modified resin, and that η1 also be within a range that can be appropriately dispersed in the resin. For example, the functional group equivalent is preferably 100 to 20.000, and more preferably 600 to 1.000. If the functional group equivalent is less than 100, the crosslinking density of the silicone oil crosslinked product will be too high, reducing the stress reduction effect, and
If it exceeds 0.000', it becomes difficult to crosslink, the silicone oil is dispersed as oil droplets in the resin, and unreacted substances seep out, which causes problems, and the dispersibility of the silicone oil deteriorates, reducing the effect of reducing stress. Decrease. As molecular weight, 200~i
o o, o o o are preferable, and U4 is more preferable
00 to 70.000.

If the molecular weight is less than 200, heat resistance @ impact resistance will decrease, and i o
If it exceeds o, o o o o v, the dispersibility of the silicone oil will be poor and the effect of reducing stress will be reduced.

The particle size of the silicone oil dispersed in the silicone modified resin and internally crosslinked is preferably 0.01 to 70 μm, more preferably 0.05 to 60 μm. If it is less than 0.01 μm, thermal shock resistance will decrease, and if it is less than 0.01 μm,
If it exceeds m2, the low stress effect will decrease.

The content of these silicone oils in the silicone-modified resin of the present invention is preferably 2 to 50% by weight, more preferably 3 to 40% by weight. If it is less than 2% by weight, the effect of reducing stress will decrease, and if it exceeds 50% by weight, the dispersibility of the silicone oil in the resin will decrease.

Next, as a dispersant to be used during the reaction of silicone modified resin, silicone oil in phenol resin or epoxy resin? Any silicone compound that can be dispersed and does not interfere with the reaction is sufficient, and is preferably represented by the following general formula.

R1 represents hydrogen, methyl, group, ethyl group, or phenyl group; R2 represents an alkyl group having 1 to 5 carbon atoms; group, carboxyl group, mercapto group, or phenyl group. Further, Y is a functional group having a repeating unit, and represents an oxyethylene polymer, an oxyalkylene polymer, or a copolymer thereof, and Y is directly bonded to a silicon atom. It's okay. 1, where n is an integer and indicates O. There are no particular limitations on this terminal group, but -〇R1R,
-08i(R)3 and -81(R)3 (R represents hydrogen, an alkyl group such as a methyl group or an ethyl group, an allyl group such as a phenyl group, an epoxy group-containing organic group, or a vinyl group-containing organic group) Those represented by are preferred.

The molecular weight of this silicone compound is 2000 to 200.
000 is preferable; if it is less than 2,000 k, thermal shock resistance will decrease, and if it exceeds 200,000 k, the dispersibility of silicone oil will deteriorate.

The functional group equivalent of epoxy group, amine group, carboxyl group, mercapto group or phenyl group is 150 to 20.00
0 is preferable, and if it is less than 150, the dispersibility of silicone oil will be poor, and 20,000? If it exceeds f-, the reactivity and compatibility with the resin will decrease, and the dispersant itself will ooze out, causing mold stains.

The amount of the silicone compound used in the silicone modification m-finger reaction is preferably 0.1 to 20% by weight; if it is less than 0.1% by weight, the dispersibility of the silicone oil will decrease, and if it exceeds 20% by weight, the moisture resistance will deteriorate. do.

The amount of silicone modified resin added to the entire epoxy resin composition is preferably 0.5 to 60% by weight, and 0.5 i
! If it is less than 60 weight IL, the effect of reducing stress will decrease.
- If it exceeds, the strength of the molded article will decrease.

A method for producing silicone modified resin includes, for example, melting a phenol resin or epoxy resin at t110 to 180°0,
Preferably, after adding triphenylphosphine/1,8 diazobicyclo(5,4,0) undecene (hereinafter abbreviated as DBU), a mixture of a dispersant and silicone oil is added, and the mixture is stirred for a predetermined period of time. One example is to cause a reaction. At this time, it is necessary to disperse the silicone oil to a particle size of t70 or less, and to cause the silicone oils to cross-link with each other sufficiently. Specifically, it is preferable to cause 20% or more of the functional groups of the silicone oil to undergo a crosslinking reaction within the oil boundary in the silicone modified resin in order to prevent seepage of the silicone oil.

The epoxy resin used in the present invention is not particularly limited in molecular structure, molecular weight, etc., as long as it has at least two or more epoxy bonds in its molecule.

Examples include bisphenol A type epoxy resin, phenol novolac type epoxy resin, Kreborg novolac type epoxy resin, etc. In this case, it is desirable to use one with less impurities and hydrolyzable chlorine.Next, as the phenol resin, Examples include phenol novolac resin and cresol novolac resin. There are no particular restrictions on the amounts used, but it is necessary that the epoxy group and curing agent be present in stoichiometric amounts.

Furthermore, the method of adding the epoxy resin or phenol resin is as follows:
The entire amount required for the epoxy resin composition may be added during the pre-reaction with the silicone-modified resin, or only the required amount may be added during the pre-reaction and the remainder may be added at the same time as the other components.

Examples of the inorganic photonic agent used in the present invention include powders of crystalline silica, fused silica, talc, alumina, calcium silicate, calcium carbonate, and glass fiber, which have high purity and low coefficient of thermal expansion. It is preferable to use crystalline silica and fused silica.

The shapes of these inorganic photonic agents include those with a substantially fractured surface, those without a fractured surface, such as spherical, ball-shaped, gourd-shaped, can-shaped, rod-shaped, etc., or even a mixture thereof. No problem.

The average particle size of the inorganic photonic agent is 0.5 to 150-5 μm, preferably 1 to 60 μm. If the average particle size is less than 0.5 μm, the composition will have low fluidity when melted, and will also have low stress properties.
In particular, heat shock resistance also deteriorates. M*is
If it exceeds oμF "f", mold leakage or wire flow may occur during molding.

The specific surface area of Maku inorganic filler is 0.1 to 15 mF/g
Preferably it is 0.5-1Qs2/g. Specific surface. If it exceeds 9ism", 'yr, the fluidity of the composition during melting will decrease, and the low stress properties, especially the heat shock resistance, will also decrease.

The inorganic photonic agent is 150 parts by weight per 100 parts by weight of the resin (epoxy@finger, phenol resin for hardening agent, brominated epoxy resin for flame retardant, and phenol-modified silicone compound).
The amount added is preferably 1 part by weight of ~900'' IjLI, more preferably 200 to 700 parts by weight.
If the amount is less than 900 parts by weight, the low stress properties, particularly thermal shock resistance, will deteriorate, which is undesirable, and if it exceeds 900 parts by weight, the fluidity of the composition when melted will decrease, which is undesirable.

Other ingredients that may be added as needed include silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, imidazoles, heptadosephines such as triphenylphosphine, curing accelerators such as DBH, and carbon Pigments such as black, montana wax,
Examples include mold release agents such as carnauba wax or Hoechst wax, and flame retardants such as brominated epoxy resin and antimony dioxide.

The resin composition of the present invention can be obtained by stirring and mixing each component and additives in a mixer, kneading with heated rolls, cooling, cooling, and pulverizing.

(Example) In the following Examples and Comparative Examples, "regret" and "part" are all based on weight r.

Examples 1 to 9 Phenol nobilac resin or 0-cresol nopolac epoxy resin 4 was prepared by adding the silicone oil having the structure shown in Table 1 and the silicone compound as a dispersant in the amount shown in Table 2.
0 parts, triphenylphosphine or n5U0.2
Next, the mixture was reacted with 140°C for 6 hours. The resulting product was pulverized using a Henschel mixer and then mixed with other ingredients in the nine proportions (parts) shown in Table 2 using a mixer. Also, for phenol resin and epoxy resin, add the missing amount (t) and add (9) so that the added amount is as shown in Table 2. Then this mixture? It is kneaded with heated rolls, cooled, and then crushed to produce nine types of molding materials. Table 3 shows the results of each evaluation.

Comparative Examples 1 to 7 Silicone-modified resins were produced in the same manner as in Examples using various organic silicone compounds and other materials in the nine ratios shown in Table 2.
This and other materials were mixed and kneaded to form a molding material and evaluated. Table 3 shows the evaluation results.

Evaluation of each physical property 1) Stress evaluation Kamezeko evaluates the internal stress r of semiconductor elements!
A resistive element (a piezoresistor whose resistance value changes with stress is formed on a semiconductor chip) is set in the frame of a T16 DIP type IC, transfer molded with each composition, and the stress applied to the element is measured. My friend.

2) Heat shock resistance evaluation A 16-bin lead frame with an island size of 4 x 7.5 inches was transfer molded using each composition.
V! -196°C liquid and +26°C
The crack occurrence rate r on the surface of the molded product was determined from 50 samples by repeating immersion in a liquid at 0° C. for 50 seconds each.

6) Moisture resistance evaluation Using each composition, a device with opposing aluminum wire electrodes was transfer molded, and the sealed sample was heated at 125°C and under a steam pressure of 2.5 atm, with a direct current of 20V between the electrodes. The bias voltage r) was applied, and the open defect rate of the aluminum wire over time was calculated using a sample value of 50.
Obtained from individuals. This test is called 28PCT (Bias Pressure Test). Similarly, even under non-bias conditions, do Tess) k, this Tess)? ! -PC
It is called T (pressure test).

4) Stampability evaluation method Each composition was molded using a semiconductor t-transfer molding method to prepare a sealed sample. This is stamped with ink (
Manufactured by Markem Associates Co., Ltd.; Product name: Markem 722
4) and after-cured at 120°C for 100 minutes, the sealability was evaluated as 9.

Stamp performance is evaluated based on the wettability of the marking ink to the surface of the semiconductor device and the adhesion strength of the ink.

(1) The wettability of the ink is determined by the repellency of the ink.
Judgment was made with the naked eye as ○ to X. ○...no cracks, △...repellents and feet, X...repellents (2) The adhesion strength of the ink is determined by imprinting on Triclean and after-curing the semiconductor device (t) after soaking it for 5 minutes. A brush whose bristles are made of pig hair (manufactured by Nakaya Plushi Kogyo Co., Ltd., No. 11)? The marking was determined by rubbing the stamped surface with one hand five times in one direction, and repeating this cycle once until the stamp partially disappeared. The table shows the number of cycles r.

5) Adhesion test with IC package transport tape (hereinafter abbreviated as carrier tape) Various compositions were molded using the half-body t-transfer bottom method to create sealed samples.

This gear rear tape (manufactured by Toyo Kagaku Co., Ltd., product name, %
554N), and the degree of adhesion was measured using a tensile test method.

The sealing force is 15 to 9 for the sample sealed on the carrier tape.
/cr Adhesion strength when pressed for 5 seconds with a load of IL2 [Tensile strength 12 (measured at a speed of 1 m/min using a tensile tester, measured value
It was calculated by dividing by the tight crushing surface (8t) with the semiconductor device.

Tensile strength measurement value / 24 tm” = adhesion force 6) Mold stain evaluation method Sealing mold t Melamine resin (Nippon Carbide Industries Co., Ltd.)
After sealing and cleaning the mold 5 times with Meiko Cullet ESR%AB G■ (trade name) manufactured by Meiko Co., Ltd., the degree of dirt on the mold was evaluated after molding 50 times in a row with various pieces.9.

The degree of staining was judged by the naked eye as O to ×.

O...no stains, △...slight stains, ×...stains II II II
II I+= and MijII II
II II
II II Guardian δ
S = black log-- ll II 11- day
C Ichidawa+1 11 ll II
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(Effects of the Invention) As described above, the present invention can be applied to a specific silicone modified resin by adding it to an epoxy resin composition, forming a sealing molding. Excellent in reducing the internal stress of the product and improving thermal shock resistance and moisture resistance reliability.
In addition, it has good properties against mold stains during molding, marking properties on molded products, and adhesion to Φ Yaria tape, and exhibits excellent effects in sealing electronic components such as semiconductors.

Patent applicant Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] (1) (a) At least two types of silicone oils having functional groups that can react with each other are dispersed as oil droplets in a phenol resin or epoxy resin using a dispersant, and the silicone oils are subjected to a crosslinking reaction within the oil droplets. An epoxy resin composition comprising: (b) an epoxy resin; (c) a phenol resin; and (d) an inorganic filler.