JP2002322243A - Method of production for epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an epoxy resin composition for sealing a semiconductor device excellent in fluidity, practically free from aggregated products and unfilled parts in molding time. SOLUTION: This method of production for the epoxy resin composition which includes (A) an epoxy resin, (B) a phenolic resin, (C) a hardening accelerator, (D-1) a surface treated filler obtained by treating an inorganic filler having average particle size >=3 μm with a coupling agent and (D-2) an inorganic filler having average particle size <=2 μm and untreated surface in the weight ratio of the [(D-1)/(D-2)]=100/(1-45), mixes a mixture of one or more components of the (A)-(C) with the component (D-1) and a mixture of the residual components of the (A)-(C) with the component (D-2) and then heating and kneading.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an epoxy resin composition for semiconductor encapsulation which has excellent solderability due to high filling of an inorganic filler, has excellent fluidity, and contains almost no agglomerates. The present invention relates to a semiconductor device.

[0002]

2. Description of the Related Art Transfer molding of an epoxy resin composition is suitable as a method for encapsulating semiconductor elements such as ICs and LSIs at a low cost and suitable for mass production. The phenol resin has been improved to improve the characteristics. However, in recent market trends of miniaturization, weight reduction, and high performance of electronic equipment, semiconductor integration has been progressing year by year, and surface mounting of semiconductor devices has been promoted. The demands on the composition are becoming increasingly demanding.
For this reason, a problem which cannot be solved by the conventional epoxy resin composition has come out. The biggest problem is that the adoption of surface mounting causes the semiconductor device to be rapidly exposed to a high temperature of 200 ° C. or more in the solder immersion or solder reflow process, and the moisture absorbed by the device explosively evaporates, causing the semiconductor device to have a stress. This is a phenomenon that cracks occur or peeling occurs at the interface between the cured parts of the epoxy resin composition and various plated joints on the semiconductor element, the lead frame, and the inner leads, and the reliability is significantly reduced. .

[0003] In order to improve the reliability reduction due to the solder reflow treatment, the amount of the inorganic filler in the epoxy resin composition is increased to achieve low moisture absorption, high strength, low thermal expansion, and solder resistance. And using a resin having a low melt viscosity to maintain low viscosity and high fluidity during molding. However, when a large amount of an inorganic filler is added to the epoxy resin composition, the melt viscosity of the epoxy resin composition at the time of molding increases, and the fluidity deteriorates and problems such as poor filling occur. It must be as low as possible. In order to maintain the melt viscosity of the epoxy resin composition and increase the amount of the inorganic filler, a filler having a large particle size and a filler having a small particle size are used in combination, that is, a material having a wide particle size distribution is used. It has been known. Also, in order to control the interface between the resin and the inorganic filler, methods of surface-treating the inorganic filler with a silane coupling agent are known. However, even with these methods, the melt viscosity during molding is insufficiently reduced. At the same time, there is a problem that a large amount of aggregates of the inorganic filler are generated, which causes clogging of the gate at the time of molding, and unfilling of the package occurs.

As a technique for solving these problems, Japanese Patent No. 3033445 discloses that when fillers having different average particle sizes are used in combination, only the larger particle size of the silane containing an alkoxy group or a partial hydrolyzate thereof is used. It is proposed to mix them without surface treatment with an alkoxy group-containing silane or a partial hydrolyzate thereof on the smaller particle size, and to some extent improved in terms of aggregates and fluidity. . However, since a filler having a large particle diameter treated with an alkoxy group-containing silane or a partial hydrolyzate thereof and a small particle filler not surface-treated with an alkoxy group-containing silane or a partial hydrolyzate thereof are directly mixed, In order to completely prevent the aggregation of the filler, the coupling agent on the surface of the large filler easily comes into contact with the filler with the small particle size, and the coupling agent adheres to the small filler with a large amount. Not reached.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a semiconductor sealing material which has excellent solderability due to high filling of an inorganic filler, has excellent fluidity, contains almost no agglomerates and is not filled during molding. An object of the present invention is to provide a method for producing an epoxy resin composition and a semiconductor device.

[0006]

The present invention provides (1) (A)
Epoxy resin, (B) phenolic resin, (C) curing accelerator, (D-1) a surface-treated filler obtained by treating an inorganic filler having an average particle diameter of 3 μm or more with a coupling agent, and (D-2)
An inorganic filler having an average particle diameter of 2 μm or less, which has not been subjected to surface treatment, has a weight ratio of [(D-1) / (D-2)] = 100 /
(1 to 45), a mixture obtained by mixing at least one of the components (A) to (C) and the component (D-1), and further the remaining components (A) to (C); After mixing the component (D-2),
A process for producing an epoxy resin composition for encapsulating a semiconductor, characterized by heating and kneading; (2) an epoxy resin (A);
(B) phenolic resin, (C) curing accelerator, (D-1)
A surface-treated filler obtained by treating an inorganic filler having an average particle diameter of 3 μm or more with a coupling agent and (D-2) an inorganic filler having an average particle diameter of 2 μm or less that has not been subjected to surface treatment have a weight ratio of [(D-1) ) / (D-2)] = 100 / (1 to 45), and a mixture obtained by mixing at least one of the components (A) to (C) with the component (D-2); The remaining (A) ~
(3) The method for producing an epoxy resin composition for semiconductor encapsulation, wherein the component (C) and the component (D-1) are mixed and then heated and kneaded, (3) Item (1) or (2). A semiconductor device characterized in that a semiconductor element is sealed using the epoxy resin composition of (1).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin used in the present invention refers to all monomers, oligomers and polymers having two or more epoxy groups in one molecule, such as orthocresol novolak epoxy resin and phenol novolak epoxy resin. Resin, dicyclopentadiene-modified phenol type epoxy resin, naphthol type epoxy resin,
Triphenolmethane type epoxy resins, phenol aralkyl type (having a phenylene skeleton or diphenylene skeleton) epoxy resin and the like may be used, and these may be used alone or in combination.

The phenolic resin used in the present invention refers to all monomers, oligomers and polymers having two or more phenolic hydroxyl groups in one molecule, such as phenol novolak resin, phenol aralkyl (having a phenylene skeleton or a diphenylene skeleton). ) Resins, naphthol aralkyl (having a phenylene skeleton or diphenylene skeleton), terpene-modified phenolic resin, dicyclopentadiene-modified phenolic resin, naphthol resin and the like, and these may be used alone or as a mixture. The equivalent ratio of the number of epoxy groups of all epoxy resins to the number of phenolic hydroxyl groups of all phenolic resins is preferably in the range of 0.7 to 1.5. If the ratio is out of this range, the curability of the epoxy composition is reduced, or Lower glass transition temperature,
It is not preferable because the reliability of humidity resistance is lowered.

The curing accelerator used in the present invention may be any one which promotes the curing reaction between an epoxy group, a curing agent and a phenolic hydroxyl group.
1,8-diazabicyclo (5,4,0) undecene-7
And the like, organic phosphorus compounds such as tetraphenylphosphonium / tetraphenylborate and triphenylphosphine, and imidazole compounds such as 2-methylimidazoles. The amount of the curing accelerator is not particularly limited, but may be 0.05 to 1 in the total epoxy resin composition.
It is preferable to set it to about weight%.

The average particle size of the inorganic filler (D-1) used in the present invention is 3 μm or more, preferably 5 to 30 μm.
The range of μm is desirable. When the average particle diameter is smaller than 3 μm, the effect of using the inorganic filler having a smaller average particle diameter of the component (D-2) is not exhibited. On the other hand, if it exceeds 30 μm, the filling property in the narrow portion during molding is undesirably reduced. Examples of the inorganic filler used in the present invention include a melting silicide force, a crystalline silicic force, alumina, silicon nitride, and aluminum nitride which are usually used for a sealing material. The shape of the inorganic filler may be a crushed shape or a spherical shape.However, in order to improve solder cracking resistance, high filling is performed.In addition, spherical fused silica is used in view of the balance of flow characteristics, mechanical strength and thermal characteristics. preferable.

As the coupling agent for treating the inorganic filler, conventionally known coupling agents can be used.
Titanium-based and aluminum-based ones are preferred, for example, γ-glycidoxypropyltrimethoxysilane, γ-mercaptotrimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfane, γ-aminopropyltriethoxy Silane, bis (3-trimethoxysilylpropyl) amine, methyl-3- [2- (3
-Trimethoxysilylpropylamino) ethylamino]
Propionate, N- (1,3-dimethylbutylidene)
-3- (triethoxysilyl) -1-propanamine,
[3- (2-aminoethyl) aminopropyl] trimethoxysilane, N-6- (aminohexyl) -3-aminopropyltrimethoxysilane, N- [3- (trimethoxysilyl) propyl] -1,3- Benzenedimethanamine, N-phenyl-γ-aminopropyltrimethoxysilane, N- (vinylbenzylmethylamino) -propyltrimethoxysilane, 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate and the like These partial hydrolysates can also be used, and these may be used alone or as a mixture. The amount of the coupling agent used is preferably from 0.1 to 1 part by weight, more preferably from 0.2 to 0.8 part by weight, per 100 parts by weight of the inorganic filler having an average particle diameter of 3 μm or more. is there. 0.
If the amount used is less than 1 part by weight, the effect of the coupling agent treatment is hardly exhibited when the surface treatment filler is blended, while if the amount used is more than 1 part by weight, aggregates are easily formed, and molding is performed. At times, the package may not be filled due to clogging of the gate, which is not preferable.

The method of preparing the surface-treated filler of the component (D-1) is not particularly limited, but the coupling agent is sprayed or the like onto the inorganic filler placed in a known mixer such as a Henschel mixer. And then mixing with an inorganic filler. In order to further reduce the aggregates, it is preferable to leave the aggregates at room temperature for several days or heat-treat them, and then remove the aggregates through a 100 to 200 mesh sieve.

On the other hand, the average particle size of the inorganic filler (D-2) is 2 μm or less, preferably 0.2 to 2 μm.
As the inorganic filler used in the present invention, conventionally known inorganic fillers can be used, and examples thereof include crushed or spherical fused silicide, crystalline silicic, alumina, silicon nitride, and aluminum nitride. . Also, two or more inorganic fillers having different average particle diameters, materials and shapes may be used in combination.

The amount of the inorganic filler (D-2) is in the range of 1 to 45 parts by weight, preferably 5 to 30 parts by weight, per 100 parts by weight of the surface-treated filler of the component (D-1). Is desirable. If the amount is less than 1 part by weight, the melt viscosity at the molding temperature in the case of an epoxy resin composition cannot be sufficiently reduced, and if it exceeds 45 parts by weight, it becomes economically disadvantageous or agglomeration occurs. This is not preferred because it easily occurs and the melt viscosity during molding increases.

The surface-treated filler of the component (D-1) and (D-
2) The inorganic filler of the component is not directly mixed, and
A mixture obtained by mixing at least one of the component (C) and the component (D-1), and further the remaining components (A) to (C), (D-
2) The components are mixed, and the components (D-1) are mixed so as not to come into direct contact with the components (D-2), or
A mixture obtained by mixing one or more of the component (C) and the component (D-2), and the remaining components (A) to (C), and (D-
It is necessary to mix the component (1) with the component (D-2) so that the component (D-2) does not directly contact the component (D-1). When mixed in this manner, the coupling agent on the surface of the surface-treated filler (D-1) does not come into contact with the inorganic filler (D-2), and effectively prevents aggregation of the inorganic filler. be able to. When the component (D-1) and the component (D-2) are directly mixed, the coupling agent on the surface of the surface-treated filler of the component (D-1) comes into contact with the component (D-1), and this coupling occurs. The filler causes aggregation of the filler frequently, and the package is not filled due to clogging of the gate during molding. Further, the melt viscosity at the molding temperature is increased, which may cause deformation of the gold wire, which is not preferable. (D-1) component or (D-
2) In the pre-process of mixing the component and at least one of the components (A) to (C), other additives other than the essential components (A) to (C) may be added and mixed. , Or (A) ~
The total amount of the component (C) and other additives may be mixed with the component (D-1) or (D-2). In the present invention, (D-
The component (1) and the component (D-2) are essential, but if necessary, an inorganic filler other than the component (D-1) and the component (D-2), which has not been treated with a coupling agent, may be added. .
The mixing method is not particularly limited, and a known mixer such as a Henschel mixer or a ball mill may be used.

The epoxy resin composition obtained by the production method of the present invention has a low melt viscosity at the time of molding, maintains good fluidity, and hardly generates aggregates. Extremely useful. The total blending amount of the component (D-1) and the component (D-2) used in the present invention is as follows:
70 to 95% by weight of the total epoxy resin composition is preferred,
More preferably, the content is 75 to 93% by weight. If the amount is less than 70% by weight, the amount of moisture absorbed by the cured product of the epoxy resin composition increases, and the mechanical strength at the solder reflow treatment temperature decreases. If it exceeds 95% by weight, the fluidity of the epoxy composition during molding is reduced, and unfilling, shift of semiconductor elements and pad shift are liable to occur, which is not preferable.

The epoxy resin composition of the present invention comprises (A)
In addition to the component (D-2), if necessary, a coupling agent such as γ-glycidoxypropyltrimethoxy, a coloring agent such as carbon black, a flame retardant such as a phosphorus compound, a silicone oil, a silicone rubber and the like. Various additives such as a low stress component, a release agent such as a natural wax, a synthetic wax, and paraffin, and an antioxidant can be blended. The epoxy resin composition of the present invention comprises a mixture obtained by mixing at least one of the components (A) to (C) with the component (D-1) or the component (D-2), and the remaining (A) After uniformly mixing the component (C), the component (D-2) or the component (D-1) at room temperature, the mixture is further melted and kneaded with a hot roll or a kneader and cooled to obtain a sealing material. In order to manufacture a semiconductor device by encapsulating an electronic component such as a semiconductor element using the epoxy resin composition of the present invention, the molding may be performed by a molding method such as a transfer mold, a compression mold, and an injection mold.

[0018]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples. The mixing unit is parts by weight. The method for treating the inorganic filler and the method for mixing the raw materials in the examples and comparative examples are shown below. Method of treating inorganic filler (A) Method: After charging only the inorganic filler of A in Table 1 into a Henschel mixer and mixing for 5 minutes, spraying γ-aminopropyltriethoxysilane in a blending amount shown in Table 1 by spraying. After mixing for 10 minutes, leave for 1 day at room temperature
Treated with a 00 mesh sieve. The processed product is hereinafter referred to as (A). (A + B) Method: After charging the inorganic fillers of A and B in Table 1 into a Henschel mixer and mixing for 5 minutes, spraying γ-aminopropyltriethoxysilane in the blending amount shown in Table 1 with a spray, and then for 10 minutes After mixing and leaving at room temperature for 1 day, the mixture was treated with a 100 mesh sieve. The processed product is hereinafter referred to as (A + B).

Mixing method of each component Of the components (A) to E in Table 1, only the components shown in mixing method 1 were mixed for 5 minutes using a Henschel mixer, and then the components shown in mixing method 2 And mix for 5 minutes. In mixing method 3 of Example 3, the component E was further blended and mixed for 5 minutes.

Example 1 Orthocresol novolak type epoxy resin (softening point 55 ° C., epoxy equivalent 196 g / eq) 10.3 parts by weight Phenol novolak resin (softening point 81 ° C., hydroxyl equivalent 104 g / eq) 5.5 parts by weight Triphenylphosphine 0.1 parts by weight Carbon black 0.2 parts by weight Antimony trioxide 1.5 parts by weight Brominated phenol novolak epoxy resin 1.5 parts by weight Carnauba wax 0.3 parts by weight γ-glycidoxypropyltrimethoxy 0.2 parts by weight of silane 80.4 parts by weight of the inorganic filler (A) obtained by the above method were mixed by the mixing method shown in Table 1, kneaded at 80 ° C. using a biaxial roll, cooled, and ground. A composition was obtained. The obtained composition was evaluated by the following method. Table 1 shows the results.

Evaluation method Spiral flow: Measurement was performed using a mold for measuring spiral flow according to EMMI-1-66 at a mold temperature of 175 ° C., an injection pressure of 70 kg / cm ² and a curing time of 2 minutes. The unit is cm. Melt viscosity: The viscosity was measured at 175 ° C. under a load of 10 kg using a Koka type flow tester CFT-500C manufactured by Shimadzu Corporation. The unit is Pa · s. Agglomerate: Approximately 100 g of a powder (2 mm or less) of the composition was precisely weighed, and a solution dissolved in 200 ml of acetone was passed through a 65-mesh sieve while washing with acetone, and the weight on the sieve was measured. Of the aggregate. Units%. Unfilled package: 80pQFP (package size 14 × 20 × 2.7 m) at a molding temperature of 175 ° C. and injection pressure of 100 kg / cm ² using a low pressure transfer molding machine
m, gate size width 0.8 mm, depth 0.35 mm) were molded into 24 packages, and the number of unfilled packages was observed.

Examples 2 to 7, Comparative Examples 1 to 4 Compounds were prepared according to the formulations shown in Tables 1 and 2 to obtain compositions in the same manner as in Example 1, and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

According to the present invention, a method for producing an epoxy resin composition for semiconductor encapsulation which is excellent in fluidity, contains almost no agglomerates and is not filled at the time of molding, and has improved soldering properties due to high filling of an inorganic filler. An excellent semiconductor device can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/31 F-term (Reference) 4J002 CC032 CD041 CD061 CD071 CD171 CE002 DE018 DE147 DE148 DF017 DJ007 DJ008 DJ017 DJ018 EN016 EU096 EU116 EW136 EW176 FB087 FB097 FB167 FD142 FD156 GQ05 4J036 AD08 AE05 AF06 AF09 DB05 DC03 DC41 DC46 DD07 FA03 FA04 FA05 FA06 FB08 JA07 4M109 AA01 BA01 CA21 EA02 EB03 EB04 EB06 EB12 EB13 EB15 EC20

Claims (3)

[Claims] 1. A surface-treated filler obtained by treating (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D-1) an inorganic filler having an average particle diameter of 3 μm or more with a coupling agent, and (D-2) 2 μm average particle size without surface treatment
m or less of the inorganic filler is [(D-1) / (D
-2)] = 100 / (1 to 45), and (A) to
A mixture obtained by mixing at least one of the component (C) and the component (D-1), and further the remaining components (A) to (C), (D-
2) A method for producing an epoxy resin composition for semiconductor encapsulation, which comprises mixing the components and heating and kneading the components. 2. A surface-treated filler obtained by treating (A) an epoxy resin, (B) a phenol resin, (C) a curing accelerator, (D-1) an inorganic filler having an average particle diameter of 3 μm or more with a coupling agent, and (D-2) Average particle size 2 without surface treatment
[(D-1) /
(D-2)] = 100 / (1 to 45), and (A)
A mixture obtained by mixing at least one of the components (C) to (D-2) and the component (D-2), and the remaining components (A) to (C), (D)
-1) A method for producing an epoxy resin composition for semiconductor encapsulation, which comprises mixing the components and then heating and kneading the components. 3. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition according to claim 1.