JPH07118506A - Semiconductor-sealing resin composition and semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the title compsn. with a high thermal conductivity, low stress properties, and excellent flowability and moldability. CONSTITUTION:The compsn. contains an epoxy resin, a curative, and an inorg. filler which comprises 60-100wt.% alumina particles with an average particle size of 5mum or higher based on whole fillers and 0-40wt.% at least either silica particles with an average particle size of 10mum or lower or spherical crystalline silica particles with an average particle size of 70mum or higher and which has a particle size distribution satisfying that the n-value of the Rosin-Rammler equation in the range of particle sizes of from 1mum to the max. size is 0.60-0.93 and that the coefficient of correlation of regression line is 0.990 or lower.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a resin composition for semiconductor encapsulation which has high thermal conductivity and excellent stress resistance, moldability and fluidity, and a cured product of the resin composition for semiconductor encapsulation. The present invention relates to a stopped semiconductor device.

[0002]

2. Description of the Related Art Currently,
MCMs (multi-chip modules) and ASICs are becoming more and more versatile because the miniaturization and speeding up of portable computers and communication devices incorporating integrated circuits are becoming active.
High-speed circuits like this have high thermal conductivity because they generate heat.
It is necessary to seal with a low stress encapsulant,
The mainstream method has been to seal with a ceramic having a small linear expansion coefficient and a high thermal conductivity, or to seal a high thermal conductive metal such as a copper plate as a radiator plate with a low stress type resin sealant.

However, ceramic encapsulation has a drawback that the cost is too high and it is not suitable for general use, and the use of a heat radiating plate causes the package to become thick, which makes it impossible to reduce the size.

In order to solve this drawback, a method of encapsulating with a semiconductor encapsulating resin composition containing a highly heat-conductive inorganic filler such as silicon nitride, aluminum nitride, alumina, crystalline silica, etc. 62-43415 and alumina: Japanese Patent Laid-Open No. 61-218622), but when silicon nitride or aluminum nitride is used as the inorganic filler, there is a drawback that reliability such as humidity resistance is greatly reduced. Further, crystalline silica has a large linear expansion coefficient and is unsuitable as a filler for a sealing material that requires low stress.

Therefore, at present, alumina, which is relatively less reliable than silicon nitride or aluminum nitride and has a small linear expansion coefficient, is preferably used as such a high thermal conductivity inorganic filler.

However, as the speed of integrated circuits increases, it is necessary to further improve the thermal conductivity. Therefore, a technique for highly filling the high thermal conductive filler is required. For example, as a method of increasing the filling rate of alumina, coarse alumina having an average particle diameter of 8 to 35 μm and fine spherical alumina and / or silica having an average particle diameter of 0.1 to 4 μm are used in an amount of 2 to 35 parts by weight of the filler. %, There is known a method for improving fluidity by mixing the same (JP-A-4-18445). However, in this method, the fluidity depends on the shape of the particle size distribution and the slope of the cumulative particle size distribution curve. Not paying attention, and as a result, insufficient improvement of liquidity.

Further, in a usual semiconductor encapsulant using fused silica, the particle size distribution of the fused silica is adjusted so that the n value of the Rosin-Rammler formula is in the range of 0.6 to 1.5 in order to highly fill the fused silica. Adjustment method (Japanese Patent Laid-Open No. 63-12802)
No. 0). However, since the fluidity also depends on the shape of the particle size distribution, it is necessary to consider the correlation coefficient between the cumulative particle size distribution curve representing this shape and the regression line,
At present, there has not been proposed a technique for increasing the packing density of the packing material using the correlation coefficient and the n value as indexes. Further, in the fused silica system, the fluidity is best when the n value is around 0.95 (Japanese Patent Laid-Open No. 63-128020), but in the alumina-containing system, high fluidity cannot be obtained by adjusting the particle size distribution as described above. Since it has not been examined, it cannot be filled with alumina at a high level, and low linear expansion and further high thermal conductivity have not yet been realized.

The present invention has been made in view of the above circumstances, and is a resin composition for semiconductor encapsulation which has high thermal conductivity and excellent stress resistance, moldability, and fluidity, and the resin composition for semiconductor encapsulation. It is an object of the present invention to provide a semiconductor device sealed with the cured product of.

[0009]

Means and Actions for Solving the Problems The present inventors have
As a result of earnestly studying to achieve the above object, in a resin composition for semiconductor encapsulation containing an epoxy resin, a curing agent and an inorganic filler, a filler as shown below as an inorganic filler, that is, (i) Alumina particles having an average particle size of 5 μm or more are contained in an amount of 60 to 100% by weight of the entire filler, and (i
i) Containing silica particles having an average particle size of 10 μm or less, spherical crystalline silica particles having an average particle size of 70 μm or more, or mixed silica particles thereof in an amount of 0 to 40% by weight of the entire filler,
Moreover, the n value of the rosin-Rammler formula from the particle size of 1 μm to the maximum particle size of the inorganic filler composed of (i) and (ii) is 0.60 to 0.93, and the correlation coefficient of the regression line is 0. ．
By using an inorganic filler having a particle size distribution of 990 or less, it is possible to obtain a resin composition for semiconductor encapsulation which is excellent in moldability and fluidity while giving a cured product having high thermal conductivity and low stress. They have found out the present invention and made the present invention.

The present invention will be further described below. The resin composition for semiconductor encapsulation of the present invention comprises (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler as an essential component. It is a thing.

Here, the epoxy resin of the component (A) used in the present invention is not particularly limited in its molecular structure, molecular weight and the like, as long as it is a compound having at least two epoxy groups in its molecule. Type, bisphenol type, biphenyl type epoxy resin, epoxy resin such as naphthalene skeleton-containing epoxy resin, and the like. These epoxy resins can be used alone or in combination of two or more kinds, but the sealing material is filled with a high amount of filler. In order to obtain the resin composition for use, it is particularly preferable to use the biphenyl type epoxy resin having a low melt viscosity alone.

On the other hand, the curing agent of the component (B) used in the present invention is not particularly limited in molecular structure, molecular weight and the like as long as it is a compound having two or more functional groups capable of reacting with the epoxy resin. Examples thereof include novolac type, bisphenol type, biphenyl type phenol resin, naphthalene skeleton-containing phenol resin, and further curing agents such as amine curing agents. These curing agents can be used alone or in combination of two or more. .

The epoxy resin of component (A), (B)
The compounding amount of the curing agent as the component is not particularly limited, but to 1 mol of the epoxy group contained in the epoxy resin as the component (A), the phenolic OH contained in the curing agent as the component (B).
The molar ratio of the groups is preferably 0.5 to 1.5.

The inorganic filler as the component (C) used in the present invention comprises (i) 60 to 100% by weight of the entire filler of alumina particles having an average particle size of 5 μm or more, and (ii) an average particle size of 10 μm. The following silica particles or average particle size is 70μ
A particle size of the inorganic filler containing 1 to 40% by weight of spherical crystalline silica particles of m or more or mixed silica particles thereof in an amount of 0 to 40% by weight of the entire filler, and comprising (i) and (ii) above.
The n value of the Rosin-Rammler formula from μm to the maximum particle size is 0.60 to 0.93, and the correlation coefficient of the regression line is 0.990.
It has the following particle size distribution.

The method for measuring the particle size distribution of the filler is as follows. (1) Measuring method of average particle size Laser diffraction type particle size distribution measuring device (Cirrus, HR85
It is measured in 0). (2) Method for measuring n value and correlation coefficient of Rosin-Rammler equation The data obtained in (1) is converted into a Rosin-Rammler diagram by the following Rosin-Rammler equation, and the maximum particle diameter is converted to a particle diameter of 1 μm. Draw a regression line up to
Here is calculated the correlation coefficient between the value) regression line R (Dp) = 100 · exp (-b · Dp n), Dp; particle size R (Dp); accumulated from the maximum particle diameter up to Dp wt% n, b; constant

Specifically, the above-mentioned inorganic filler is, first, various alumina particles having different arbitrary particle size distributions, alone or mixed at an arbitrary ratio, to obtain alumina particles having an average particle diameter of 5 μm or more. Silica particles having an average particle size of 10 μm or less obtained by using the alumina particles thus obtained alone or in the same manner as the above alumina particles and / or spherical crystalline silica having an average particle size of 70 μm or more obtained in the same manner as the above alumina particles The particles are mixed with the above proportions to prepare the inorganic filler having the optimum particle size distribution as described above. At this time, it is preferable that the gradient of the cumulative particle size distribution curve of the inorganic filler thus obtained does not change suddenly at any point. The filler having a particle size distribution in which the slope of the cumulative particle size distribution shows a sharp change at any point,
Reduces fluidity compared to a particle size distribution that does not show abrupt changes.

In the alumina-containing system such as the inorganic filler, unlike the fused silica system, the n-value of the rosin-Rammler formula of the inorganic filler is 0.60 to 0.60 as described above.
The flowability can be remarkably improved only when the particle size distribution is adjusted to 0.93, more preferably 0.65 to 0.85, but a sealing resin composition further filled with a filler is highly added. It is particularly preferable to use spherical alumina and spherical silica in order to obtain

Since the resin composition containing the above-mentioned inorganic filler becomes a resin composition having remarkably excellent moldability and fluidity, it is possible to increase the filling amount of the inorganic filler, resulting in high thermal conductivity. Gives a cured product excellent in low stress. An inorganic filler that does not satisfy this condition, that is, a resin composition containing 60% by weight or more of alumina particles having an average particle size of less than 5 μm based on the total weight of the inorganic filler has insufficient moldability and fluidity. You cannot increase the amount. In addition, the alumina particles are added to the inorganic filler 60%.
If the amount is less than wt%, sufficient thermal conductivity cannot be obtained. Similarly, if the content of silica is more than 40% by weight of the whole inorganic filler, sufficient thermal conductivity cannot be obtained. Furthermore,
Rosin with a particle size of 1 μm to the maximum particle size of the inorganic filler
When the n value of the Lambler formula is other than 0.60 to 0.93 or when the correlation coefficient of the regression line of the rosin-Rammler formula is larger than 0.990, the formability and fluidity are remarkably insufficient, As a result, a cured product having a high thermal conductivity and a low stress is provided.

When the above-mentioned inorganic filler of the present invention is filled, a resin composition having excellent moldability and fluidity is obtained, so that the filling amount of the inorganic filler can be increased, and as a result, high thermal conductivity can be obtained. A cured product having excellent properties and low stress can be obtained. From this point of view, therefore, it is desirable that the resin composition contains 85% by weight or more of the inorganic filler in order to obtain sufficiently high thermal conductivity and low stress.

In the present invention, the surface treatment of the inorganic filler with a coupling agent such as a silane coupling agent or a titanate coupling agent improves low water absorption, thermal shock resistance and crack resistance. Is preferred. As the coupling agent, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, epoxysilane such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-β- (Aminoethyl) -γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, aminosilane such as N-phenyl-γ-aminopropyltrimethoxysilane, mercaptosilane such as γ-mercaptotrimethoxysilane, and the like. It is preferable to use a silane coupling agent. Here, the amount of the coupling agent used for the surface treatment and the surface treatment method are not particularly limited.

Further, in the present invention, it is preferable to use a curing catalyst in order to accelerate the curing reaction between the epoxy resin (A) and the curing agent (B). The curing catalyst is not particularly limited as long as it accelerates the curing reaction, and examples thereof include triphenylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, triphenylphosphine / triphenylborate,
Phosphorus compounds such as tetraphenylphosphine and tetraphenylborate, triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, 1,8
-A tertiary amine compound such as diazabicyclo (5.4.0) undecene-7, an imidazole compound such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole and the like can be used.

The encapsulating resin composition of the present invention is an epoxy resin,
Although the curing agent and the inorganic filler are essential components, waxes, flame retardants, colorants, and the like can be added and blended as long as the object of the present invention is not impaired.

As a general method for preparing the encapsulating resin composition of the present invention as a molding material, epoxy resin,
A curing agent, the inorganic filler, and other additives are blended at a predetermined composition ratio, and after sufficiently mixing them with a mixer or the like, a melt mixing process with a hot roll or a kneader is performed, followed by cooling and solidification, It can be crushed to an appropriate size to obtain a molding material. The molding material thus obtained can be provided with excellent characteristics and reliability when it is used for sealing or covering electronic components such as semiconductor devices or electrical components.

The semiconductor device of the present invention can be easily manufactured by encapsulating a semiconductor element using the encapsulating resin composition. Examples of the semiconductor element for sealing include, but are not limited to, integrated circuits, transistors, thyristors, diodes, and the like.
The transfer molding method is mentioned as the most general method of sealing. Further, it is preferable that the encapsulating resin composition is further heated after molding to be post-cured. here,
Post-curing is preferably performed under heating conditions of 150 ° C. or higher.

[0025]

EFFECT OF THE INVENTION The encapsulating resin composition of the present invention can be highly filled with a high thermal conductive filler having a specific particle size distribution as compared with a conventional high thermal conductive encapsulating resin composition, and thus is used for semiconductor encapsulation. It has excellent high thermal conductivity, low stress, and moldability, as well as excellent fluidity. The semiconductor encapsulating device encapsulated with the cured product of the encapsulating resin composition of the present invention is excellent in high thermal conductivity and low stress, has a good balance of characteristics, and is highly reliable.

[0026]

EXAMPLES Hereinafter, the present invention will be specifically shown by showing 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 and Comparative Examples] The following components were uniformly melt-mixed with a hot two-roll, cooled and pulverized to obtain Examples 1 to 1.
7. Resin compositions for semiconductor encapsulation of Comparative Examples 1 to 4 were obtained. It should be noted that the filler of Comparative Example 4 exhibits the best fluidity in Japanese Patent Laid-Open No. 18445/1992 (the particle size distribution is 4.7% by weight of alumina having an average particle size of 24 μm and the average particle size of 10 μm). 81.3% by weight of alumina, average particle size is 1μ
m is a filler having a high thermal conductivity of 14.1% by weight of fine spherical silica particles. Composition Epoxy resin 54.5 parts (Yukaka Shell Epoxy Co., TX-4000H, epoxy equivalent 190 g / mol) Phenolic resin 24.3 parts (Mitsui Toatsu Chemical Co., Inc., Milex XL-225, hydroxyl equivalent 168 g / mol) Phenolic resin 15.0 parts (MEH7710, manufactured by Meiwa Kasei Co., hydroxyl equivalent 137 g / mol) Brominated epoxy resin 6.2 parts (AER755, epoxy equivalent 459 g / mol, manufactured by Asahi Ciba) Curing catalyst (triphenylphosphine) 1 0.5 parts Antimony trioxide 8.0 parts Colorant (Mitsubishi carbon black) 1.5 parts Silane coupling agent (Shin-Etsu Chemical Co., Ltd., KBM-403) 2.0 parts Release agent (carnauba wax)

Next, the following tests were conducted on the obtained composition. The results are shown in Tables 1 and 2. (A) Spiral flow value Using a mold conforming to the EMMI standard, 175 ° C, 70
It was measured under the conditions of kg / cm ² and molding time of 120 seconds. (B) Thermal conductivity of 175 ° C., 70 kg / cm ² , molding time of 120 seconds, and molding at 120 ° C. for 4 hours, and heating after 50 m
A test piece of mφ x 6 mm was inserted between the upper heater and the calorimeter and the lower heater in a sandwich shape, and was brought into constant contact with air pressure, and the temperature difference between both surfaces of the test piece after reaching a steady state at 50 ° C, The thermal conductance was automatically calculated from the calorimeter output, and the thermal conductivity was determined from the product of the value of this thermal conductance and the thickness of the test piece. (C) Formability 100-pin QFP (Package size: 14 mm x 20
(mm × 2.2 mm) using a transfer molding machine under the conditions of 175 ° C., 70 kg / cm ² , and 2 minutes, and the appearance defect (void) at this time was measured.

[0029]

[Table 1]

[0030]

[Table 2]

From the above examples, the cured product of the encapsulating resin composition containing the high thermal conductive inorganic filler of the present invention has excellent high thermal conductivity, low stress, excellent fluidity, and voids. It is recognized that the moldability is excellent and the moldability is excellent.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01L 23/31 (72) Inventor Koji Nimori Mitsuda-cho, Usui-gun, Gunma Prefecture 1 Hitomi Hitoshi 10 Shin-Etsu Chemical Industrial Co., Ltd. Silicon Electronic Materials Research Laboratory (72) Inventor Eiichi Asano 1 Hitomi, Osamu Matsuida-cho, Usui-gun, Gunma Shin-Etsu Chemical Co., Ltd. Silicon Electronic Materials Research Laboratory

Claims (2)

[Claims] 1. A semiconductor encapsulating resin composition containing an epoxy resin, a curing agent, and an inorganic filler, wherein (i) alumina particles having an average particle size of 5 μm or more are used as the inorganic filler in the entire filler. 60 to 100% by weight, and (i
i) Containing silica particles having an average particle size of 10 μm or less, spherical crystalline silica particles having an average particle size of 70 μm or more, or mixed silica particles thereof in an amount of 0 to 40% by weight of the entire filler,
Moreover, the n value of the rosin-Rammler formula from the particle size of 1 μm to the maximum particle size of the inorganic filler composed of (i) and (ii) is 0.60 to 0.93, and the correlation coefficient of the regression line is 0. ．
A resin composition for semiconductor encapsulation, comprising an inorganic filler having a particle size distribution of 990 or less. 2. A semiconductor device encapsulated with the cured product of the composition according to claim 1.