KR900004675B1 - Epoxy resin composition for encapsulating semiconductor - Google Patents

Abstract

An epoxy resin compsn. for encapsulating semiconductor comprises: 10- 30 wt. pts. of cresolnovolac epoxy resin or phenolnovolac epoxy resin having 180-240 epoxy equivs., 60-110≰C softening point; 5-20 wt. pts. of phenolnovolac resin or cresolnovolac resin havig 70-110≰C softening point; 60-80 wt. pts. of inorg. filler; and 0.1-5 wt. pts. of hume silica having 0.010.5 of particle size, 100-300 m2 of spec. surface area. Pref. the epoxy resin comtains above 3 epoxy gp. per one molecula of that; the inorg. filler is silicon oxide, calcium carbonate, melting silica, alumina or mica.

Description

Epoxy Resin Composition for Semiconductor Sealing

The present invention relates to an epoxy resin composition for semiconductor element sealing, in particular an epoxy resin composition for semiconductor sealing excellent in fluidity and moldability.

Conventionally, glass, metals, ceramics, and the like have been used to seal semiconductor devices such as transistors, ICs, and LSIs, but in recent years, thermosetting resins such as epoxy, silicon, phenol, and phthalate systems have been used instead of these materials.

Among them, epoxy resins are widely used for electric and electronic parts and adhesives because of their excellent heat resistance, electrical properties, dimensional stability, and adhesiveness.In recent years, in recent years, high-density and large-size devices have been developed due to the trend of miniaturization and light weight of electronic parts. And epoxy resin materials have been widely used as a multifunctional semiconductor sealing material according to the compounding and the like.

The sealing material of the semiconductor device should have good heat resistance, moisture resistance, and mechanical strength, exhibit moderate hardness that does not wear the mold, and have a small difference in the coefficient of thermal expansion from the internal seal during the cooling cycle, and prevent heat generation of the semiconductor device. In order to do so, it is preferable to have good thermal conductivity.

In addition to the general required properties described above, a sealing material having excellent fluidity is particularly desired. However, if the fluidity is too high, resin flows into a small gap of the mold during molding, causing flash to deteriorate workability.

Failure to remove the flash generated on the lead wire of the semiconductor component may cause defects during the soldering process. Therefore, there is a need for a sealing composition having optimum flowability and excellent moldability in which generation of flash is suppressed.

The epoxy resin composition used as a sealing resin of the conventional semiconductor device satisfies the above general requirements, but is poor in fluidity and formability, and also adjusts the type and amount of the epoxy resin, and the particle size and particle size of the inorganic filler. As a result of adjusting the distribution, the fluidity and moldability were satisfactorily satisfied, but the mechanical strength and the moisture resistance were lowered.

Accordingly, the present inventors have invented an epoxy resin composition containing the following components as a main component that satisfies the above-described requirements of the epoxy resin for semiconductor encapsulation and removes a decrease in mechanical strength and a decrease in moisture resistance.

1) 10-30 parts by weight of a cresol noblock epoxy resin or a phenol novolac epoxy resin having an epoxy equivalent of 180-240 and a softening point of 60-110 ° C.

2) 5-20 parts by weight of a phenol novolak resin or cresol novolak resin having a softening point of 70-110 ° C.

3) 60-80 parts by weight of inorganic filler.

4) 0.1-5 parts by weight of fume silica, which has a particle size of 0.01-0.05μ and a specific surface of 100-300m ² / g.

The cresol novolak resin and phenol novolak resin of component 1) used in the present invention are epoxy equivalent 180-240 and have a softening point in the range of 60-110 ° C. as a cresol novolak epoxy resin or phenol novolac epoxy resin. If the epoxy equivalent is 240 or more in the molecule, if the epoxy equivalent is more than 240, sufficient heat resistance and mechanical strength cannot be obtained due to the decrease in crosslinking density.

In addition, when it is 60 degrees C or less, generation | occurrence | production of a flash becomes remarkably large. Bisphenol type epoxy resins other than cresol novolac epoxy resins or phenol novolac epoxy resins have a low viscosity liquid phase when the epoxy equivalent is 240 or less, resulting in a markedly low flash generation suppression property and a low heat resistance during molding.

In order to impart flame retardance to the molding material of cresol novolac epoxy resin or phenol novolac epoxy resin of component 1) above, it is preferable to use 10-30% by weight of brominated epoxy resin in all epoxy resins.

Brominated epoxy resins include novolac epoxy resins such as brominated phenol novolac epoxy resins and brominated cresol novolac epoxy resins and brominated bisphenol A epoxy resins. Here, the epoxy equivalent and softening point are not limited and known ones conventionally used can be used.

The component 2) used in the present invention is a curing agent for epoxy resins based on the component 1) as a novolak resin such as phenol novolak resins or cresol novolak resins containing two or more hydroxyl groups in a molecule, and has a softening point of 70. What is used is -110 ° C. When the amine hardener and the acid anhydride hardener are used as the hardener other than the novolak resin, the moisture resistance is deteriorated, which is inappropriate.

If the softening point is lower than 70 ℃, the freshness is remarkable. If the softening point is higher than 110 ℃, the fluidity is worsened, which causes difficulty in sealing work. 2) The usage-amount of a component is good to use in the range of 501-150 weight with respect to 100 weight of 1) components. Outside this range, hardening defects are caused and physical properties such as moisture resistance and heat resistance are reduced.

As the inorganic filler of 3) component used in the present invention, for example, silicon oxide, calcium carbonate, alumina, molten silica, crystalline silica, glass, magnesite, gypsum, graphite, cement, iron carbonyl, tar, mica, silica sand , Kaolin, aluminum hydroxide, asbestos, etc., can be used in combination of two or more. Preferably, as crystalline silica and fused silica having a median particle size of 5-30 mu, 60-80 wt% is used per weight of the precursor composition.

When using 60 wt% or less, the coefficient of thermal expansion increases, so that in the case of a semiconductor sealing device, physical properties such as heat resistance, crack resistance, and moisture resistance are deteriorated. When the wire is cut or severe, the seal becomes impossible to seal.

The fume silica, 4) component used in the present invention, is a component used only in the present invention, and unlike silica of 3) component, colloidal silicon produced by hydrolysis by burning silicon tetrachlorine vapor with hydrogen and oxygen. Dioxide, also called pyrogenic silica.

Unlike natural silica of 3), this component has the same shape as smoke and is called fume silica, and when separated, it has a tendency to form bonds and has a three-dimensional network structure that is selectively formed or destroyed depending on the presence of external force. .

In addition, the hydroxyl group is attached to the silicon atom on the particle surface during the production of fume silica, which makes the surface of the fume silica hydrophilic, allowing hydrogen bonding with other raw materials. As a result, it is excellent in controlling the free flow characteristics. It has a particle size of 0.01-0.05μ specific surface area in the range of 100-300m ² / g and its X-ray shape is amorphous. Preferably, the particle diameter of 0.012-0.2 µm is used to satisfy the characteristics of the present invention.

If the particle diameter is smaller than 0.01 μ, problems such as cutting of the bonding wire during molding due to the viscosity increase may occur. If the particle diameter is larger than 0.05 μ, a problem such as a remarkable decrease in the ability to suppress flash generation may occur. In addition, if more than 5% by weight of the total composition is added, the viscosity increase is so large that the free flow is remarkably lowered, so that when the bonding wire is cut or severe during molding, sealing becomes impossible and when used at 0.1% by weight or less, It cannot show the ability to improve properties.

The epoxy resin composition for sealing a semiconductor device of the present invention contains the above-mentioned components 1), 2), 3) and 4) as an essential component, and imidazole and 2-methyl ions for the purpose of promoting the curing rate during molding. Imidazoles such as midazole, 1,2-dimethylimidazole, 2-phenylimidazole, 2-ethylimidazole and organic phosphine systems such as triphenylphosphine, tributylphosphine and dimethylphosphine 0.1-1% by weight per weight of the precursor, inorganic flame retardants such as antimony trioxide, colorants, mold release agents, coupling agents, deterioration inhibitors, and other known additives are preferably used in combination at 10% by weight or less.

The epoxy resin molding material for semiconductor encapsulation of the present invention is obtained by uniformly mixing each component required using a mixing device such as a roll and a kneader, and the specific operation method such as the mixing procedure is not particularly limited. none.

When using the epoxy resin composition of the present invention to actually seal various semiconductors by the transfer molding method, it satisfies general characteristics such as moisture resistance, mechanical strength, and thermal conductivity, and obtains excellent effects on optimum fluidity and freshness suppression. Could.

Hereinafter, the effects of the present invention will be described with reference to Examples and Comparative Examples.

The cresol novolac epoxy resins used in the examples and comparative examples were epoxy equivalent 213 and a softening point of 79 ° C., and brominated phenol novolac epoxy resins had an epoxy equivalent of 270 and a softening point of 92 ° C., and a phenol novolac resin had a softening point of 100 ° C.

Inorganic fillers used in the present invention were used alone and mixed as molten silica and crystalline silica, having a median particle size of 12-20 µ.

Example 1-4

For the cresol novolac epoxy resin, brominated phenol novolak resin and phenol novolac resin, fumes silica of A, B, C and D shown in Table 1 was used, and 2-methylimidazole, carnaubawas, antimony trioxide, Carbon black, coupling agent, melted silica and crystalline silica are blended in the amounts shown in Table 1, and heat-kneaded between two rolls at 85-95 ° C. to be pulverized to a certain particle size for convenient use. Four kinds of epoxy resin compositions for semiconductor sealing of the present invention were obtained. The spiral and fresh properties of each composition are shown in Table 1. The freshness characteristics were measured by measuring the size of the flash at the time of molding using a mold for measuring freshness having a gap of 5 mu and 50 mu.

[Comparative Example 1-4]

In order to examine the fume silica effect of the present invention, the comparative examples of the case where no fume silica is used and the fume silica having different particle diameters are combined with the components and amounts shown in Table 1, and molded under the same conditions as in the following examples. The values and fresh characteristics of the composition after the spiral are shown in Table 1.

TABLE 1

* Note) The epoxy resin composition prepared in Example 2 shows the optimal spiral thickness and shows excellent effect when sealing the semiconductor device by transfer molding method. Here, the measurement method of spiral fluoro is a value measured according to EMMI 1-66 (Epoxy Molding Material Institute: Society of Plastic Industry) using a spiral mold as a known measurement method.

Epoxy resin compositions are good when the measurement is 70-120cm, more preferably 80-110cm.

Claims (3)

Epoxy equivalent 180-240, 10-30 parts of cresol novolac epoxy resin or phenol novolac epoxy resin at softening point of 60-110 ° C., 5-20 weight of phenol novolak resin or cresol novolac resin having softening point of 70-110 ° C. Part, 60-80 parts by weight of inorganic filler and 0.01-0.5μ particle size, 0.1-5 parts by weight of fume silica having a specific surface of 100-300m ² / g epoxy resin composition for semiconductor sealing. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the epoxy resin contains three or more epoxy groups in one molecule. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the inorganic filler is silicon oxide, calcium carbonate, molten silica, crystalline silica, alumina, mica.