JP2002275243A - Epoxy resin molding material for sealing semiconductor and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture an epoxy resin molding material for sealing semiconductors having good adhesivity between the resin and a lead frame, and having good reliability of the package after sealing the semiconductor device even in the case of high filling rate of an inorganic filler, and a semiconductor device sealed with the molding material. SOLUTION: The epoxy resin molding material for sealing semiconductors contains at least an epoxy resin, a curing agent and an inorganic filler as raw materials. The molding material contains an amide solvent as an essential component. The semiconductor device is sealed with the molding material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy having good adhesiveness between a resin and a lead frame after molding by encapsulation of a semiconductor or between a resin and a semiconductor element, and having good package reliability. The present invention relates to a resin molding material and a method for manufacturing the semiconductor device.

[0002]

2. Description of the Related Art Epoxy resin molding materials that can be transfer-molded are widely used for sealing semiconductor elements such as ICs and LSIs from the viewpoint of reliability and productivity. The epoxy resin molding material is composed of an epoxy resin, a phenol resin, a curing accelerator, a silica filler, a release agent, a flame retardant, a coupling agent, and the like. Usually, a predetermined amount of the constituent materials is weighed to obtain a Henschel mixer. Premixing using a stirring mixer such as-and then melt kneading using a heating kneader such as a single screw extruder, a twin screw extruder, a heating roll, a continuous kneader, etc. A manufacturing method of uniformly mixing and dispersing is adopted.

On the other hand, in response to the trend toward smaller and lighter electronic devices and higher performance, smaller and thinner semiconductor packages have been developed.
As the pitch becomes narrower, the epoxy resin molding compound for semiconductor encapsulation is strongly required to have improved solder heat resistance and moisture resistance related to the reliability of the semiconductor package after encapsulation. For this reason, in order to reduce the stress and moisture absorption inside the semiconductor package, the components of the epoxy resin molding material have shifted to materials having a high content of inorganic filler. However, this shift not only reduces the moldability during encapsulation molding, but also results in a reduction in package reliability, such as a decrease in adhesion between the resin and the lead frame after encapsulation molding. Have been.

As a means for improving the adhesion, a method of recently adding an aluminum chelate compound having a phosphate ester structure in the molecule (JP-A-11-302502), an indene-based polymer and an organic titanium compound and / or A method of adding a metal acetylacetonate complex (JP-A-11-012438) and a method of adding zinc diethyldithiocarbamate (JP-A-11-22879)
No. 1), a method of improving the adhesion between a resin and an interface, and a method of using triphenylphosphine and a benzoquinone adduct curing accelerator as a biphenyl-type epoxy resin and a phenolic resin curing agent having a naphthalene structure ( JP 11
166060), a method of using a specific organic phosphorus-based curing accelerator as a biphenyl-type epoxy resin and a novolak-type phenol resin-based curing agent (JP-A-11-001541)
For example, methods for improving the degree of curing of a resin have been disclosed, but these methods have a problem that the adhesion is not sufficiently improved.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to improve the adhesiveness between a resin and a lead frame after semiconductor encapsulation molding or the adhesiveness between a resin and a semiconductor element and to improve the package reliability. An object is to provide a good epoxy resin molding material and a semiconductor device.

[0006]

The present invention has been studied in view of such circumstances, and as a result, the addition of an amide-based solvent improves the mixing of the resin components and improves the adhesion between the resin and the interface. Not only that, the amide-based solvent accelerates the curing reaction of the resin, so that the degree of curing of the resin becomes uniform, and the resulting resin after encapsulation molding has good adhesion between the resin and the lead frame or between the resin and the semiconductor element. It has been found that the adhesion is improved. That is, the present invention provides an epoxy resin, a curing agent,
An epoxy resin molding compound for semiconductor encapsulation, comprising an inorganic filler and an amide solvent, wherein the amide solvent is N-methyl-2-pyrrolidone or N,
An epoxy resin molding material for semiconductor encapsulation, which is N-dimethylformamide, and a semiconductor device encapsulated with these epoxy resin molding materials for encapsulating semiconductor.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The epoxy resin used in the present invention is not particularly limited as long as it has two or more epoxy groups in one molecule and is solid at room temperature. Examples thereof include bisphenol type epoxy resin and biphenyl. Type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, alkyl-modified triphenol methane type epoxy resin, and the like. These may be used alone or in combination.

The curing agent used in the present invention is not particularly limited as long as it is a phenol resin and is a solid at room temperature. Examples thereof include phenol novolak resin, cresol novolak resin, and dicyclohexane resin. Examples thereof include a pentadiene-modified phenol resin, a phenol-aralkyl resin, a naphthol-aralkyl resin, and a tempene-modified phenol resin. These may be used alone or in combination.

The inorganic filler used in the present invention includes alumina powder, fused silica powder, crystalline silica powder, silicon nitride and the like, and these may be used alone or as a mixture. Further, as the inorganic filler, a material which has been surface-treated with a silane coupling agent in advance may be used. When using a fused silica powder, a spherical shape should be used, and the content of silica should be 60 to 94% by weight in the whole composition in consideration of a balance between moldability and reliability. preferable.

The epoxy resin molding material for encapsulating a semiconductor obtained by the present invention is, if necessary, a surface treating agent used for a filler such as γ-glycidoxypropyltrimethoxysilane in addition to the essential components described above. And a colorant such as carbon black, a release agent such as carbana wax, a low stress agent such as silicone oil, and a flame retardant such as antimony trioxide.

The present invention is characterized in that an amide solvent is added to the above-mentioned raw materials. Examples of the amide solvent include N-methyl-2-pyrrolidone (NMP) and N, N-dimethylformamide (DMF). The amide-based solvent has good compatibility with the resin, and the addition of the amide-based solvent promotes the mixing of the resin components.
The adhesion between the semiconductor device and the memory or resin is improved. In addition, the amide-based solvent promotes the curing reaction of the resin, so that the degree of curing of the resin becomes uniform. Even during use, the resin and the lead frame or the resin and the semiconductor element do not peel off due to uneven curing, so that the adhesive property is not increased. Is improved. Conventionally, imidazole, amine compounds, organic sulfonic acid compounds, etc., which have been used as curing accelerators, are solids, have poor compatibility with epoxy resins, and are difficult to disperse. In order to disperse a curing accelerator such as imidazole or the like, it must be added in excess. Even if added in excess,
It is not preferable because the resin and the lead frame or the resin and the semiconductor element are peeled off due to uneven curing and the adhesion is reduced. The amide solvent may be used alone, or may be used in combination with another substance, for example, an amine compound, an organic sulfonic acid compound, an imidazole compound, or the like, if necessary.

As a pre-mixing method, an alumina resin and another inorganic filler are added to an epoxy resin or a curing agent or a mixture of an epoxy resin and a curing agent, and the mixture is heated to a temperature equal to or higher than the melting point of the epoxy resin and the curing agent. In the mixing machine
It is preferable to use a mixer that allows the inorganic filler to be dispersed by passing the inorganic filler through the medium.

[0013]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. <Blending> Epoxy resin [3,3 ′, 5,5′-tetramethylbiphenol diglycidyl ether resin, melting point 103 ° C., epoxy equivalent 195] Phenol resin [phenol novolak resin, melting point 40]
° C, hydroxyl equivalent: 175] Brominated bisphenol A type epoxy resin [Epicoat 5050, manufactured by Yuka Shell Epoxy Co., Ltd.] Spherical silica powder [FB-74, manufactured by Denki Kagaku Kogyo Co., Ltd.] γ-glycidoxypropyltrimethoxy Silane Carbon black Carnauba wax Antimony trioxide Curing accelerator [N-methyl-2-pyrrolidone (NMP)] Curing accelerator [N, N-dimethylformamide (DM
F)] Curing accelerator [imidazole]

<Production method> A premixed mixture of the above-mentioned components in a Henschel mixer (volume: 15 liters, rotation speed: 1500 rpm) set at room temperature for 2 minutes is meshed in the same direction with a twin-screw extruder. (Screw diameter D = 30 mm, extruder length = 1 mm, kneading disk length = 6 D, screw rotation speed 300 rpm, discharge rate 20 kg / hr), and the mixture was heated and kneaded so that the resin temperature became 105 ° C. The mixture obtained by heating and kneading is cooled and then pulverized, tableted, and then subjected to low-pressure transfer molding at 175 ° C.
Solder cracking test under the conditions of 70 kg / cm ^2, 120 seconds, sealing the semiconductor element 9 × 9 mm for the temperature cycle test to 80PQFP. Examples 1 to 4 and Comparative Example 1
Table 2 shows the results of Nos. 1 to 2.

<Evaluation method> Spiral flow: molding temperature 175 ° C, molding pressure 70k
Measured by transfer molding at g / cm ² . Solder crack test: After the sealed test element was absorbed under the conditions of 85 ° C., 60% relative humidity and 168 orders, IR
Perform reflow (240 ° C., 10 seconds) three times to determine the presence or absence of package cracks. n = 10. Temperature cycle test: Sealed test element at -65 ° C ~
Repeat at 1000 cycles at 150 ° C to determine the presence of package cracks. n = 10. Moisture absorption: 3 g each of the material immediately before the melt-kneading was weighed into an aluminum cup having a diameter of 30 mm. A heat treatment is applied to solidify the material. 50% x 100% of solidified material
RH × 24Hr treatment, and the moisture absorption was calculated from the weight increase after the treatment (unit%). Adhesion: The test element after the solder crack test was observed with an ultrasonic flaw detector at the interface between the semiconductor element and the molded article of the resin composition. n = 10. Poor appearance of package surface: The appearance of the surface of 80pQFP sealed after the solder crack test was observed with the naked eye, and the presence or absence of an external defect caused by fine particles was observed. n = 10.

[0016]

[Table 1]

[0017]

According to the present invention, even if the filling rate of the inorganic filler is high, the adhesion between the resin and the lead frame after the semiconductor encapsulation molding is good and the package reliability is good. And a semiconductor device using the same.

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Claims (3)

[Claims] An epoxy resin molding material for semiconductor encapsulation, comprising an epoxy resin, a curing agent, an inorganic filler and an amide solvent. 2. The epoxy resin molding material for semiconductor encapsulation according to claim 1, wherein the amide-based solvent is N-methyl-2-pyrrolidone or N, N-dimethylformamide. 3. A semiconductor device sealed with the epoxy resin molding material for semiconductor sealing according to claim 1.