JP2812139B2 - Epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation which gives a cured product having excellent thin film curability, crack resistance and solvent resistance.

[0002]

2. Description of the Related Art In recent years, the sealing of semiconductor elements has been changing from the conventional transfer molding using solid resin to sealing bare chips using liquid resin.

Most liquid encapsulants currently on the market are those obtained by curing an epibis-type epoxy resin with an acid anhydride. However, this type of epoxy resin composition is hard and brittle, so that it is easily cracked. And it is difficult to manufacture a highly reliable semiconductor device by sealing it with a liquid resin.

On the other hand, a transparent rubber-like silicone is used as a transparent sealing material for an image sensor or the like, but the rubber surface is covered with a glass plate because of no surface hardness. In this case, encapsulation with a commercially available transparent epoxy resin is also being considered to reduce costs.However, this method involves resin peeling or cracking at the sensor due to stress during temperature cycling, or high temperature. It has the disadvantage of being easily discolored and has not yet been put to practical use. Also, LE
D and the like are also sealed with a commercially available transparent epoxy resin, but the luminance changes due to the stress generated during curing and the resin shrinkage stress at low temperatures.

[0005] The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide an epoxy resin composition for semiconductor encapsulation that has excellent thin film curability, gives a cured product having excellent crack resistance and solvent resistance, and can also provide good transparency. I do.

[0006]

Means and Action for Solving the Problems The present inventors have
As a result of diligent studies to achieve the above object, the conventional hardness by using an epoxy-modified silicone represented by the following general formula (1) in combination with a modified silicone represented by the following general formula (2) as a curing agent. However, it was possible to soften the cured epoxy resin, which was pointed out as brittleness, to reduce the stress.Also, when a silicone component was added to the conventional epoxy resin, microphase separation occurred, and the cured product became cloudy. By introducing an epoxy resin or a curing agent component into the silicone skeleton, transparency can be imparted, and the conventional acid anhydride curing agent volatilizes during heat curing, resulting in poor curing and reduced thin film curability. However, they have found that such a problem can be solved by using an acid anhydride-modified silicone.

[0007] (However, R is a monovalent hydrocarbon group, R ¹ is an organic group having an aromatic ring and an epoxy group, respectively, and has at least two or more epoxy groups in one molecule, and 0 <a <3 ,
0 <b <3 and 0 <a + b <4. ) (However, R is a monovalent hydrocarbon group, R ² is an acid anhydride group or an organic group containing a phenolic hydroxyl group, and has at least two or more R ² groups in one molecule, and 0 <c <3, 0 <
d <3 and 0 <c + d <4. )

That is, as the epoxy-modified silicone, those obtained by adding an allyl glycidyl ether to a hydroxysilyl group-containing silicone are easily available at present, and this compound is a conventionally known epibis epoxy resin or novolak epoxy resin. Not only is it incompatible with the resin, it becomes cloudy or phase-separated and cannot be used for optical applications, and there is a problem that silicone oozes out during the curing reaction. In addition, when an acid anhydride is used as a curing material, there is also a problem that when an attempt is made to cure the film in a thin film, the acid anhydride is easily volatilized to cause poor curing, or the surface portion becomes uncured, It has been found that by using the epoxy resin composition using the modified silicone of the formulas (1) and (2) of the present invention in combination, an epoxy cured product having excellent transparency and stress properties and excellent thin film curability can be obtained. It is a thing.

Accordingly, the present invention provides an epoxy resin composition for semiconductor encapsulation comprising the epoxy-modified silicone represented by the general formula (1) and the modified silicone represented by the general formula (2) as a curing agent.

Hereinafter, the present invention will be described in more detail. In the epoxy resin composition of the present invention, a linear, cyclic or three-dimensional epoxy-modified silicone represented by the following formula (1) is used as an epoxy resin component.

[0011] R _aR¹ _bSiO_{{4- (a + b)} / 2} ... (1) (where R is a monovalent hydrocarbon group, R¹Is aromatic ring and epo
An organic group containing a xy group, and in one molecule
Having at least two or more epoxy groups, 0 <a <3,
0 <b <3 and 0 <a + b <4. )

Here, R is a monovalent hydrocarbon group, and specifically represents a substituted or unsubstituted alkyl, aryl or aralkyl group having 1 to 10 carbon atoms. Further, R ¹ is an organic group containing an aromatic ring and an epoxy group, and specific examples thereof include the following.

[0013]

Embedded image (However, Me represents a methyl group.)

As the epoxy-modified silicone, linear or cyclic ones represented by the following formulas (1a) and (1b) are particularly preferred from the viewpoint of reducing stress and reducing the viscosity of the composition.

[0015]

Embedded image (Wherein, R and R ¹ have the same meanings as above, R ³ is R or R ¹ , 0 <n + m <1000, 3 <p + q <7
It is. )

Specific examples of such an epoxy-modified silicone include the following.

[0017]

Embedded image

[0018]

Embedded image

[0019]

Embedded image (However, Me indicates a methyl group and Pr indicates an n-propyl group.)

These epoxy-modified silicones may be used in combination with a conventionally known epoxy resin, and it is particularly recommended to use them in combination in order to maintain strength at high temperatures.
In this case, examples of the epoxy resin include epibis type epoxy resin, phenol novolak or cresol novolak type epoxy resin, triphenol methane type epoxy resin, biphenyl type epoxy resin, naphthalene ring-containing epoxy resin, alicyclic epoxy resin and the like. And one or more of these can be used. When these epoxy resins are used in combination, the proportion is preferably 10 to 90% by weight, more preferably 40 to 80% by weight of the total epoxy resin.
It is. If it exceeds 90% by weight, a sufficiently low stress property cannot be obtained, and if it is less than 10% by weight, there is a case where the effect of improving the strength is not sufficiently obtained. When a liquid epoxy resin composition is used among these epoxy resins, an epibis type epoxy resin or an alicyclic epoxy resin is preferable. When it is desired to significantly reduce the viscosity, a diluent such as phenylglycidyl ether can be appropriately selected and used.

The epoxy resin composition of the present invention uses a linear, cyclic or three-dimensional epoxy-modified silicone represented by the following general formula (2) as a curing agent. By using these modified silicone curing agents, it is possible to obtain characteristics, such as low stress, which could not be obtained conventionally.

[0022] (However, R is a monovalent hydrocarbon group, R ² is an acid anhydride group or an organic group containing a phenolic hydroxyl group, and has at least two or more R ² groups in one molecule, and 0 <c <3, 0 <
d <3 and 0 <c + d <4. )

Here, R is the same as that described in the above formula (1), and R ² is an acid anhydride group or an organic group containing a phenolic hydroxyl group. Is exemplified.

[0024]

Embedded image

The modified silicone of the above formula (2) includes
Particularly, those represented by the following formulas (2a) and (2b) are preferable.

[0026]

Embedded image (Wherein, R and R ² have the same meanings as above, R ⁴ is R or R ² , 0 <m + n <1000, 3 <p + q <7
It is. )

Specific examples of such modified silicones include the following.

[0028]

Embedded image

[0029]

Embedded image

[0030]

Embedded image (However, Me indicates a methyl group and Pr indicates an n-propyl group.)

The modified silicone as a curing agent may be used in combination with a conventionally known curing agent. Examples of such a curing agent include a conventionally known acid anhydride such as a phenol resin and tetrahydrophthalic anhydride, and an amine compound. When these curing agents are used in combination, the proportion is 10 to 90% by weight, more preferably 40 to 80% by weight of the total curing agents. If it exceeds 90% by weight, sufficient low stress property cannot be obtained, and if it is less than 10% by weight, there is a case where there is no effect in improving strength. Among these curing agents, in the case of a liquid epoxy resin composition, an acid anhydride type curing agent is preferable. Further, two or more of the curing agents as described above may be used in combination.

In the composition of the present invention, the equivalent ratio of the epoxy group to the curing agent is in the range of 0.5 to 2, preferably 0.9 to 1.5 per epoxy group.

In order to quickly react the epoxy group with the curing agent, it is desirable to use a curing accelerator such as a phosphorus compound, an amine derivative, a cycloamidine or an imidazole derivative.

The amount of the curing accelerator used is desirably 0.05 to 10 parts by weight per 100 parts by weight of the total amount of the epoxy resin and the curing agent. If the amount is less than 0.05 part by weight, a sufficient curing promoting effect may not be obtained, and if it exceeds 10 parts by weight, a sufficient pot life may not be obtained.

In the composition of the present invention, an inorganic filler can be used if necessary. The inorganic filler reduces the expansion coefficient of the resin composition and reduces the stress applied to an insert such as a semiconductor element. As specific examples, crushed and spherical fused silica and crystalline silica are mainly used. In this case, it is better to use a blend of a sphere and a crushed product or only a sphere product in order to achieve both low expansion of the cured product and workability. In addition, as the inorganic filler, alumina, silicon nitride, aluminum nitride, calcium carbonate, magnesium carbonate, boron nitride, glass fiber, calcium silicate and the like can also be used. In addition, this kind of inorganic filler can be used after surface treatment with a silane coupling agent in advance. Further, the surface of the inorganic filler may be treated with a two-pack type silicone rubber or silicone gel.

The average particle size of the inorganic filler is 5 to 20.
Micron ones are preferred. Further, the amount of the inorganic filler is preferably 50 to 800 parts by weight based on 100 parts by weight of the total amount of the epoxy resin and the curing agent. In some cases, the device characteristics are degraded. When the content exceeds 800 parts by weight, the viscosity of the composition becomes high, and the workability becomes poor due to a decrease in fluidity.

In the present invention, various organic synthetic rubbers, methyl methacrylate-styrene-butadiene copolymer, styrene-ethylene are used in order to impart flexibility and toughness to the cured product of the epoxy resin composition of the present invention. Thermoplastic resins such as butene-styrene copolymers and fine powders such as silicone gels and silicone rubbers can be added.

The composition of the present invention may further comprise, if necessary,
Release agents such as carnauba wax, higher fatty acids and synthetic waxes, as well as silane coupling agents, antimony oxide,
A phosphorus compound or the like may be blended.

The composition of the present invention can be produced by mixing the above components, and when molding this composition, molding methods such as potting and casting can be adopted. Further, the curing condition is 80
After curing at -100 ° C for 1-2 hours, 120-1
A step cure method of curing at 50 ° C. for about 3 to 8 hours can be employed.

[0040]

The epoxy resin composition having a resin skeleton mainly composed of the modified silicone according to the present invention has good compatibility, so that a transparent and uniform cured product can be obtained, and curing by volatilization of an acid anhydride. Since there is no defect and it is sufficiently soft even at room temperature, it has excellent stress characteristics. Further, by blending the inorganic filler, a tougher cured product can be obtained.

Therefore, the epoxy resin composition of the present invention is suitable for use in liquid sealing materials requiring transparency, such as line sensors, area sensors, and image sensors, and those containing an inorganic filler are preferred. Further, since the stress becomes low, it is suitable for sealing various kinds of highly reliable semiconductor devices.

[0042]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. Prior to the description of Examples and Comparative Examples,
Production examples of the modified silicone used in each example are shown below.

[Production Example 1] In a four-necked flask equipped with a reflux condenser, a thermometer and a dropping funnel, 4-allyl-3- was added.
52.9 g of methoxyglycidyl phenyl ether (0.
24 mol), 300 g of toluene and 0.3 g of a toluene solution of chloroplatinic acid (platinum content: 1.5% by weight) were charged.
While heating to 112 ° C., 33.4 g (0.04 mol) of the organosilicon compound of the following formula (a) was added dropwise over about 30 minutes. After the completion of the dropwise addition, the reaction was carried out at a reflux temperature for 3 hours.

[0044]

Embedded image After the reaction, a low distillate was distilled off to obtain 64.1 g of a product.
(83% yield) was obtained. NM for this product
Measurement of R, IR, and elemental analysis confirmed that the compound was an organosilicon compound having the following structural formula (I).

[0045]

Embedded image

Production Example 2 In the four-necked flask used in Production Example 1, 68.7 g (0.31 mol) of 4-allyl-3-methoxyglycidyl phenyl ether and toluene 2
50 g of a toluene solution of chloroplatinic acid (platinum content: 0.
3 g of an organosilicon compound of the following formula (b) (0.3 wt.
02 mol) was added dropwise in about 30 minutes. After the completion of the dropwise addition, the reaction was carried out at a reflux temperature for 3 hours.

[0047]

Embedded image After the reaction, a low distillate was distilled off to obtain 88.1 g of a product.
(Yield 92%) was obtained. NM for this product
Measurement of R, IR, and elemental analysis confirmed that the compound was an organosilicon compound having the following structural formula (II).

[0048]

Embedded image

[Preparation Example 3] In the four-necked flask used in Preparation Example 1, 66.1 g (0.30 mol) of 4-allyl-3-methoxyglycidyl phenyl ether and toluene 25
0 g and a toluene solution of chloroplatinic acid (platinum content 0.5
% By weight), and heated to 112 ° C., and 39.6 g (0.0%) of an organosilicon compound represented by the following formula (c) was added thereto.
1 mol) was added dropwise over about 30 minutes. After the completion of the dropwise addition, the reaction was carried out at a reflux temperature for 3 hours.

[0050]

Embedded image After the reaction, a low distillate was distilled off to obtain 80.0 g of a product.
(84.5% yield) was obtained. For this product N
When measured by MR, IR, and elemental analysis, it was confirmed that the compound was an organosilicon compound having the following structural formula (III).

[0051]

Embedded image

Production Example 4 In the four-necked flask used in Production Example 1, 29.1 g (0.13 mol) of 4-allyl-3-methoxyglycidylphenyl ether and toluene 20
0 g and a toluene solution of chloroplatinic acid (platinum content 0.5
% By weight), and while heating at 112 ° C., 40.3 g of an organosilicon compound of the following formula (d) was added thereto for about 30 minutes.
In minutes. After the completion of the dropwise addition, the reaction was carried out at a reflux temperature for 3 hours.

[0053]

Embedded image After the reaction, a low distillate was distilled off to obtain 61.7 g of a product.
(96% yield) was obtained. NM for this product
Measurement of R, IR and elemental analysis confirmed that the compound was an organosilicon compound having the following structural formula (IV).

[0054]

Embedded image

[Production Example 5] In the four-necked flask used in Production Example 1, 63.4 g (0.29 mol) of 4-allyl-3-methoxyglycidyl phenyl ether and toluene 25
0 g and a toluene solution of chloroplatinic acid (platinum content 0.5
% By weight), and heated to 112 ° C., and 14.4 g (0.0%) of an organosilicon compound represented by the following formula (e) was added thereto.
6 mol) was added dropwise over about 30 minutes. After the completion of the dropwise addition, the reaction was carried out at a reflux temperature for 3 hours.

[0056]

Embedded image After the reaction, a low distillate was distilled off to obtain 60.0 g of a product.
(89% yield) was obtained. NM for this product
Measurement of R, IR, and elemental analysis confirmed that the compound was an organosilicon compound having the following structural formula (V).

[0057]

Embedded image

[Production Example 6] Into the four-necked flask used in Production Example 1, 81.5 g of allylnadic anhydride (0.40 g) was added.
Mol), 300 g of toluene and 0.3 g of a toluene solution of chloroplatinic acid (platinum content: 0.5% by weight) were charged.
While heating to 2 ° C., 14.8 g (0.06 mol) of the organosilicon compound of the above formula (e) was added dropwise over about 30 minutes. After the completion of the dropwise addition, the low distillate was distilled off.
9.8 g (yield 72%) were obtained. NMR, IR and elemental analysis of this product confirmed that it was an organosilicon compound having the following structural formula (VI).

[0059]

Embedded image

[Production Example 7] In the four-necked flask used in Production Example 1, 54 g (0.53 mol) of allylnadic anhydride, 250 g of toluene and a toluene solution of chloroplatinic acid (platinum content 0.5% by weight) ) Charge 0.4g, 112
25.9 g (0.16 mol) of the organosilicon compound of the following formula (f) was added dropwise thereto over about 30 minutes while heating to ° C.
After the completion of the dropping, a low fraction was distilled off to obtain 71 g of a product.
(87% yield) was obtained. NM for this product
Measurement of R, IR, and elemental analysis confirmed that the compound was an organosilicon compound having the following structural formula (VII).

[0061]

Embedded image

[0062]

Embedded image

[Production Example 8] In the four-necked flask used in Production Example 1, 66.8 g (0.41 mol) of 4-allyl-3-methoxyglycidylphenyl ether and toluene 15
0 g and a toluene solution of chloroplatinic acid (platinum content 0.5
0.48 g of the organosilicon compound of the above formula (f) while heating to 112 ° C.
Mol) was added dropwise over about 30 minutes. After the completion of the dropwise addition, the low fraction was distilled off to obtain 116.4 g of the product (yield: 96%). NMR, IR and elemental analysis of this product confirmed that it was an organosilicon compound having the following structural formula (VIII).

[0064]

Embedded image

[Examples 1 to 12, Comparative Examples 1 and 2] The modified silicone obtained in the above Production Example and a bisphenol A type epoxy resin (trade name RE31) were used as the epoxy resin.
0, liquid at room temperature, manufactured by Nippon Kayaku Co., Ltd., methylhexahydrophthalic anhydride (trade name MH70) as an acid anhydride curing agent
0, liquid at room temperature, manufactured by Shin Nippon Rika Co., Ltd., 1-methyl-2-ethylimidazole (trade name: Curesol 1M2WZ, liquid at room temperature, manufactured by Shikoku Chemicals) as a curing accelerator, silica-based inorganic filler (trade name) FB35, average particle size10.
(3 μm, manufactured by Denki Kagaku Kogyo Co., Ltd.) were used in the amounts shown in the table and mixed using a gate mixer.

After mixing, each composition was subjected to the following test to evaluate its properties. The results are shown in the table. (1) Gelation time The gelation time of the composition was measured at 150 ° C. (2) Surface hardness The composition was placed in an aluminum Petri dish so as to have a thickness of 3 mm, pre-cured at 100 ° C for 1 hour, and then cured at 150 ° C for 4 hours. The surface hardness of the cured product was measured with a Barcol hardness meter (GYZ935). (3) Solvent Resistance The cured product whose surface hardness was measured was left in acetone for 20 hours at room temperature to examine the solvent resistance. ：: no change, ：: surface swelling, ×: dissolved (4) Thin film curability After the composition was screen-printed on a glass plate to a thickness of 50 microns, it was cured at 100 ° C. for 1 hour and at 150 ° C. for 4 hours. Was. The test piece was left in acetone for 4 hours, and the surface condition was observed. ：: no change, ：: surface swelling, ×: dissolution (5) Crack resistance A nut having a diameter of about 3 cm was placed in an aluminum Petri dish, and the composition was cast thereon, followed by 150 ° C. at 100 ° C. for 1 hour.
For 4 hours. Hardened sample directly at 150 ° C
And then immersed in dry ice-methanol at −70 ° C. to observe the occurrence of cracks. The number of cracked samples among the five test samples was shown.

[0067]

[Table 1]

[0068]

[Table 2]

The cured products of Examples 1 to 9 containing no inorganic filler were all light yellow transparent or light brown transparent and uniform with excellent compatibility.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuhiro Arai 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Inside Silicone Electronics Materials Research Laboratory Shin-Etsu Chemical Co., Ltd. (72) Inventor Kazuo Dobashi Matsui, Usui-gun, Gunma Prefecture Hitomi Tamachi 1-10, Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (72) Inventor Sachi Wakao 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (56) References JP-A-60-179417 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08G 59/20 C08G 59/40 C08L 83/06 H01L 23/29

Claims (3)

(57) [Claims] 1. An epoxy resin composition for semiconductor encapsulation comprising an epoxy-modified silicone represented by the following general formula (1) and a modified silicone represented by the following general formula (2) as a curing agent. (However, R is a monovalent hydrocarbon group, R ¹ is an organic group having an aromatic ring and an epoxy group, respectively, and has at least two or more epoxy groups in one molecule, and 0 <a <3 ,
0 <b <3 and 0 <a + b <4. ) (However, R is a monovalent hydrocarbon group, R ² is an acid anhydride group or an organic group containing a phenolic hydroxyl group, and has at least two or more R ² groups in one molecule, and 0 <c <3, 0 <
d <3 and 0 <c + d <4. ) 2. The epoxy resin composition according to claim 1, further comprising an inorganic filler. 3. The epoxy-modified silicone of the formula (1) contains 10 to 90% by weight of the total epoxy resin, and the modified silicone of the formula (2) contains 10 to 90% by weight of the total curing agent.
The epoxy resin composition according to claim 1, further comprising: