JP6558671B2 - Epoxy resin composition for sealing and semiconductor device - Google Patents

Description

  The present invention relates to an epoxy resin composition for sealing and a semiconductor device, and more particularly to an epoxy resin composition for sealing and a semiconductor device suitable for single-side sealing.

  Conventionally, a single-sided mold type semiconductor device has been manufactured by forming a sealing material from a sealing epoxy resin composition on one side of a substrate (see Patent Document 1).

  When such a semiconductor device is manufactured, the occurrence of warpage becomes a problem. For example, when manufacturing a wafer level package as a semiconductor device, in order to improve manufacturing efficiency, an IC, a rewiring layer, etc. are formed on one side of a large-sized wafer, and a sealing material is formed on one side of this wafer. It is desirable to cut the wafer to obtain a wafer level package. However, in that case, when a sealing material is formed on one side of a large-sized wafer, there is a problem that warpage is likely to occur.

  It is known that the warpage of a semiconductor device increases as the temperature at the time of molding the sealing epoxy resin composition increases.

  However, conventionally, when an epoxy resin composition for sealing is molded at a low temperature, the moldability deteriorates, and it becomes difficult to form a particularly thin sealing material. It was easy to occur. In addition, warping could not be sufficiently suppressed.

JP 2009-235211 A

  The present invention has been made in view of the above-described reasons, and can reduce the molding temperature and suppress warpage of the semiconductor device when forming a sealing material for a single-sided mold type semiconductor device. An object of the present invention is to provide a sealing epoxy resin composition that can be sealed, and a single-sided mold type semiconductor device sealed with the sealing epoxy resin composition.

  The epoxy resin composition for sealing according to the present invention contains an epoxy resin, a curing agent, and an inorganic filler. The epoxy resin is represented by the following general formula (1), and the ICI viscosity at 150 ° C. is 0.00. It contains a naphthylene ether skeleton-containing epoxy resin that is 1 Pa · s or less, and the curing agent contains an imidazole compound.

Two R ^{1 s} in the formula (1) each independently represent a hydrogen atom or a methyl group, and a plurality of R ^{2 s} are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aralkyl group, or a naphthalene group. Represents a glycidyl ether group-containing naphthalene group or a glycidyl ether group-containing phenyl group, and n is a number of 1 or more.

  The sealing epoxy resin composition according to the present invention preferably contains a phenol resin, and the equivalent ratio of the epoxy resin to the phenol resin is preferably 2.0 or more.

  The melting point of the imidazole compound is preferably in the range of 100 to 185 ° C.

  The percentage of the naphthylene ether skeleton-containing epoxy resin with respect to the total amount of the epoxy resin composition for sealing according to the present invention is preferably in the range of 3 to 49% by mass.

  The percentage of the inorganic filler relative to the total amount of the epoxy resin composition for sealing according to the present invention is preferably in the range of 50 to 93% by mass.

  The percentage of the imidazole compound relative to the epoxy resin is preferably in the range of 1.2 to 6.2% by mass.

  The average particle size of the inorganic filler is preferably in the range of 2 to 20 μm.

  The 1% mass loss temperature of the cured epoxy resin composition according to the present invention is preferably 265 ° C. or higher.

  The semiconductor device according to the present invention includes a base material and a sealing material that covers one side of the base material and is made of a cured product of the sealing epoxy resin composition.

  The substrate is preferably made of a wafer.

  The base material may be a wiring board, a semiconductor chip may be mounted on the one surface of the base material, and the semiconductor chip may be sealed with the sealing material.

  The sealing material is formed by molding the sealing epoxy resin composition by a compression molding method, and the thickness of the sealing material is preferably 1.2 mm or less.

  The semiconductor device according to the present invention may include one or more semiconductor chips and a sealing material made of a cured product of the sealing epoxy resin composition formed in a sheet shape on one surface of the semiconductor chip. .

  According to the present invention, even if the molding temperature when molding the epoxy resin composition for sealing is lowered, the moldability is hardly deteriorated and the unevenness of the sealing material hardly occurs, and sealing is performed on one side of the substrate. By molding the epoxy resin composition for forming a sealing material, a single-sided mold type semiconductor device in which warpage is suppressed can be obtained.

  Hereinafter, embodiments of the present invention will be described.

  In this embodiment, the epoxy resin composition for sealing contains an epoxy resin, a curing agent, and an inorganic filler.

  The epoxy resin contains a naphthylene ether skeleton-containing epoxy resin. The naphthylene ether skeleton-containing epoxy resin is represented by the following general formula (1). Furthermore, the ICI viscosity at 150 ° C. of the naphthylene ether skeleton-containing epoxy resin is 0.1 Pa · s or less.

Two R ^{1 s} in the formula (1) each independently represent a hydrogen atom or a methyl group, and a plurality of R ^{2 s} are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aralkyl group, or a naphthalene group. Or a glycidyl ether group-containing naphthalene group, and n is a number of 1 or more.

  Furthermore, the curing agent contains an imidazole compound.

  When the sealing epoxy resin composition according to the present embodiment is molded to form a sealing material, even if the molding temperature is lowered, it is difficult for deterioration of moldability and occurrence of unevenness of the sealing material to occur. This is presumed that the naphthylene ether skeleton-containing epoxy resin has good fluidity even when the molding temperature is low, and the reactivity between the naphthylene ether skeleton-containing epoxy resin and the imidazole compound is good even at low temperatures. Is done.

  Moreover, when the sealing epoxy resin composition according to the present embodiment is molded on one side of a base material to form a sealing material for a single-sided mold type semiconductor device, warping of the semiconductor device is suppressed. This is because a resin cured product having a naphthylene ether skeleton is contained in the sealing material by molding an epoxy resin composition for sealing, and the rigidity resulting from the naphthylene ether skeleton is thermally expanded in this resin cured product. It is speculated that the warpage was suppressed as a result.

  For example, crystalline epoxy resins that have been generally used for conventional sealing applications have a high melting point. For this reason, when a sealing material is formed at a low temperature using a composition containing a crystalline epoxy resin without containing a naphthylene ether skeleton-containing epoxy resin, the moldability deteriorates and the uniformity of the sealing material is reduced. It becomes worse and unevenness is likely to occur in the sealing material.

  Moreover, in this embodiment, since the epoxy resin composition for sealing contains a naphthylene ether skeleton-containing epoxy resin, an inorganic filler, and imidazole, the melt viscosity of the epoxy resin composition for sealing and the glass transition temperature of the sealing material Easy to balance with.

  The composition of the sealing epoxy resin composition according to this embodiment will be described in more detail.

  The epoxy resin in the epoxy resin composition for sealing contains a naphthylene ether skeleton-containing epoxy resin as described above.

  As described above, the naphthylene ether skeleton-containing epoxy resin has a structure represented by the formula (1).

  For example, a naphthylene ether skeleton-containing epoxy resin can have a structure represented by the following formula (1-1).

As described above, the two R ¹ in the formula (1) each independently represent a hydrogen atom or a methyl group. It is obvious that changing R ¹ from hydrogen to a methyl group or changing from a methyl group to hydrogen does not significantly affect the physical properties and reactivity of the naphthylene ether skeleton-containing epoxy resin. Here, independent means that two R ¹ are both hydrogen atoms, two R ¹ are both methyl groups, or two R ¹ are a hydrogen atom and a methyl group, respectively.

As above-mentioned, several R < ² > in Formula (1) is each independently a hydrogen atom, a C1-C4 alkyl group, an aralkyl group, a naphthalene group, a glycidyl ether group containing naphthalene group, or a glycidyl ether group containing Represents a phenyl group. The aralkyl group is, for example, a methylphenyl group.

The structure of R ² affects the melt viscosity of the naphthylene ether skeleton-containing epoxy resin. That is, the bulk viscosity of R ² tends to increase the melt viscosity of the naphthylene ether skeleton-containing epoxy resin. In addition, when R ² contains a glycidyl ether group-containing naphthalene group, the reactivity of the naphthylene ether skeleton-containing epoxy resin increases, and the glass transition point of the cured product of the naphthylene ether skeleton-containing epoxy resin increases.

In addition, the aralkyl group affects the melt viscosity of the naphthylene ether skeleton-containing epoxy resin. Depending on the type of the aralkyl group, the naphthyl ether skeleton-containing epoxy resin has a low melt viscosity, and the naphthylene ether skeleton-containing epoxy resin has a low viscosity. The melt viscosity may increase. Therefore, when R ² contains an aralkyl group, it is preferable to select the type of aralkyl group so that the ICI viscosity at 150 ° C. is 0.1 Pa · s or less.

Moreover, the dispersibility of the inorganic filler in the sealing epoxy resin composition can be adjusted by selecting R ² . By appropriately selecting R ² according to the type of the inorganic filler, etc., the dispersibility of the inorganic filler is improved, thereby making it easy to use the epoxy resin composition for sealing using a biaxial kneader or the like. Can be prepared.

  As described above, n in the formula (1) is a number of 1 or more. As the value of n increases, the melt viscosity of the naphthylene ether skeleton-containing epoxy resin tends to increase.

  The naphthylene ether skeleton-containing epoxy resin may contain only one type of compound having the structure shown in Formula (1), or may contain two or more types of compounds having the structure shown in Formula (1).

  The naphthylene ether skeleton-containing epoxy resin not only has the structure represented by the formula (1), but also has an ICI viscosity at 150 ° C. of 0.1 Pa · s or less. That is, even when the naphthylene ether skeleton-containing epoxy resin contains only one or two or more compounds having the structure represented by the formula (1), the ICI viscosity at 150 ° C. of the naphthylene ether skeleton-containing epoxy resin is 0. .1 Pa · s must not be exceeded.

  As described above, the melt viscosity of the naphthylene ether skeleton-containing epoxy resin is affected by the type of substituent and the value of n in the formula (1). For this reason, the ICI viscosity at 150 ° C. of the naphthylene ether skeleton-containing epoxy resin is such that the type of substituent in the compound contained in the naphthylene ether skeleton-containing epoxy resin, the number of n in the formula (1), etc. It is easily adjusted by adjusting the structure. In other words, the type of substituent and the value of n in formula (1) can be appropriately selected so that the naphthylene ether skeleton-containing epoxy resin has a desired melt viscosity.

  The ICI viscosity at 150 ° C. of the naphthylene ether skeleton-containing epoxy resin can also be adjusted by adding a plurality of compounds having different melt viscosities to the naphthylene ether skeleton-containing epoxy resin at an appropriate ratio.

For example, only a compound represented by the formula (1), wherein n in the formula (1) is 2 or more and all R ² in the formula (1) is a glycidyl ether group-containing naphthalene group, contains a naphthylene ether skeleton. When the epoxy resin is contained, the ICI viscosity at 150 ° C. of the naphthylene ether skeleton-containing epoxy resin may exceed 0.1 Pa · s. Such an epoxy resin composition for sealing containing a naphthylene ether skeleton-containing epoxy resin having a high melt viscosity is excluded from this embodiment.

  The number of glycidyl ether groups per molecule in the naphthylene ether skeleton-containing epoxy resin is preferably in the range of 2.1 to 3.9. In this case, the heat resistance of the sealing material is improved by increasing the crosslinking density of the cured product of the naphthylene ether skeleton-containing epoxy resin. In addition, when this number is less than 2.1, the crosslinking density of hardened | cured material falls and the heat resistance of a sealing material falls. If this number is larger than 3.9, the heat resistance of the encapsulant is improved by increasing the crosslink density of the cured product, but the melting point of the naphthylene ether skeleton-containing epoxy resin is increased, so The kneadability at the time of kneading the component containing the naphthylene ether skeleton-containing epoxy resin to prepare the resin composition is lowered.

  The value of n in the formula (1) and the average molecular weight of the naphthylene ether skeleton-containing epoxy resin are not particularly limited. However, these values are naturally limited so that the ICI viscosity at 150 ° C. of the naphthylene ether skeleton-containing epoxy resin is 0.1 Pa · s or less.

  The percentage of the naphthylene ether skeleton-containing epoxy resin relative to the total amount of the epoxy resin composition for sealing is preferably in the range of 3 to 49% by mass. In this case, deterioration of the moldability of the epoxy resin composition for sealing and occurrence of unevenness in the sealing material are less likely to occur, and warping of the semiconductor device is further unlikely to occur. The percentage of the naphthylene ether skeleton-containing epoxy resin relative to the total amount of the epoxy resin composition for sealing is preferably in the range of 3 to 10% by mass.

  The epoxy resin preferably contains only a naphthylene ether skeleton-containing epoxy resin, but the epoxy resin may contain a compound other than the naphthylene ether skeleton-containing epoxy resin within a range not departing from the object of the present invention. The percentage of the naphthylene ether skeleton-containing epoxy resin with respect to the total amount of the epoxy resin in the epoxy resin composition for sealing is preferably in the range of 30 to 100% by mass, and more preferably in the range of 50 to 100% by mass. preferable.

  When the epoxy resin contains a compound other than the naphthylene ether skeleton-containing epoxy resin, the epoxy resin is, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy in addition to the naphthylene ether skeleton containing epoxy resin. Resin, phenol novolac type epoxy resin, alkylphenol novolac type epoxy resin, aralkyl type epoxy resin, biphenol type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, biphenyl type epoxy resin, anthracene type epoxy resin, phenols and phenol One or more selected from the group consisting of epoxidized products of condensates with aromatic aldehydes having a functional hydroxyl group, triglycidyl isocyanurate, and alicyclic epoxy resins It can contain compound.

  As described above, the curing agent contains an imidazole compound. That is, in this embodiment, when the epoxy resin composition for sealing is thermally cured, the cured resin is formed by the reaction between the epoxy resin in the epoxy resin composition for sealing and the imidazole compound. In this embodiment, since the curing agent contains an imidazole compound, the reactivity between the naphthylene ether skeleton-containing epoxy resin and the imidazole compound is improved even when the molding temperature is relatively low.

  Specific examples of the imidazole compound include 2-phenylimidazole (melting point: 137 to 147 ° C.), 2-phenyl-4-methylimidazole (melting point: 174 to 184 ° C.), and 2-phenyl-4,5-dihydroxymethylimidazole (decomposition). Temperature 230 ° C.).

  The imidazole compound is preferably solid at 25 ° C. Furthermore, it is preferable that the melting point of the imidazole compound is as low as possible. Specifically, the melting point of the imidazole compound is preferably in the range of 100 to 185 ° C. In this case, when the imidazole compound is melted at the time of molding, the fluidity of the epoxy resin composition for sealing is increased and the moldability is improved, and the reactivity between the naphthylene ether skeleton-containing epoxy resin and the imidazole compound is high. Thus, the uniformity of the sealing material is improved. More preferably, the melting point of the imidazole compound is in the range of 100 to 150 ° C.

  The percentage ratio of the imidazole compound to the total amount of the epoxy resin in the sealing epoxy resin composition is preferably in the range of 1.2 to 6.2% by mass. In this case, the reactivity between the epoxy resin and the imidazole compound is particularly good, and the unreacted components are less likely to remain in the sealing material, and the epoxy resin composition for sealing has curability with an excellent balance. It is more preferable that the imidazole compound is in the range of 2.6 to 4.0% by mass with respect to the total amount of the epoxy resin.

  It is also preferable that the equivalent ratio of the epoxy resin to the imidazole compound in the sealing epoxy resin composition is in the range of 0.01 to 0.5. In this case, the reactivity between the epoxy resin and the imidazole compound becomes particularly good, and the unreacted component hardly remains in the sealing material. When the equivalence ratio is less than 0.1, the curing reaction is too slow and the curing time is delayed. When it is more than 0.5, the curing reaction is too fast and the moldability may be affected.

  It is preferable that the epoxy resin composition for sealing does not contain a phenol resin. When the epoxy resin composition for sealing contains a phenol resin, it is preferable that the content of the phenol resin is small. In this case, the reaction involving the phenol resin and the imidazole compound is less likely to occur in the sealing epoxy resin composition, and the storage stability of the sealing epoxy resin composition is increased.

  When the epoxy resin composition for sealing contains a phenol resin, the equivalent ratio of the total amount of the epoxy resin in the epoxy resin composition for sealing to the phenol resin is preferably 2.0 or more. In this case, the storage stability of the epoxy resin composition for sealing is particularly high. It is particularly preferable if this equivalent ratio is 5 or more.

  When the epoxy resin composition for sealing contains a phenol resin, the phenol resin can contain at least one of, for example, a triphenylmethane type phenol resin and a phenol novolac resin.

  Examples of the inorganic filler include silica such as fused silica, spherical fused silica, and crystalline silica; high dielectric constant filler such as aluminum oxide, magnesium oxide, boron nitride, aluminum nitride, high dielectric constant barium titanate and titanium oxide; hard ferrite Magnetic fillers such as magnesium hydroxide, aluminum hydroxide, antimony trioxide, antimony pentoxide, guanidine salt, zinc borate, molybdenum compound, zinc stannate and other inorganic flame retardants; talc; barium sulfate; calcium carbonate; One or more materials selected from the group consisting of mica powder can be contained.

  It is particularly preferable that the inorganic filler contains spherical fused silica. In this case, the fluidity of the sealing epoxy resin composition during molding is particularly high. Moreover, the filling property of the inorganic filler in the sealing material can be easily improved.

  The average particle size of the inorganic filler is preferably in the range of 2 to 20 μm. In this case, the fluidity of the sealing epoxy resin composition during molding is particularly good. The average particle diameter is a volume-based cumulative median diameter (median diameter d50) based on a measured value of the particle size distribution by a laser diffraction / scattering method using a laser diffraction / scattering particle size distribution measuring apparatus. More preferably, the average particle size of the inorganic filler is in the range of 5 to 15 μm.

  The percentage of the inorganic filler relative to the total amount of the epoxy resin composition for sealing is preferably in the range of 50 to 93% by mass. In this case, the fluidity of the sealing epoxy resin composition during molding is particularly good. The percentage of the inorganic filler is preferably in the range of 80 to 93% by mass.

  The sealing epoxy resin composition may contain appropriate additives such as a curing accelerator and a release agent in addition to the above components.

  When the sealing epoxy resin composition contains a curing accelerator, the curing accelerator includes, for example, quaternary phosphonium salts such as tetraphenylphosphonium and tetraphenylborate, organic phosphines such as triparatolylphosphine and triphenylphosphine, and One or more components selected from the group consisting of tertiary amines such as diazabicycloundecene can be contained.

  The curing accelerator is used for sealing, particularly when the sealing epoxy resin composition contains a phenolic resin and the reactivity between the epoxy resin and the phenolic resin affects the curability of the sealing epoxy resin composition. It is preferable to contain in an epoxy resin composition.

  When the epoxy resin composition for sealing contains a release agent, the release agent contains, for example, one or more components selected from the group consisting of carnauba wax, stearic acid, montanic acid, and carboxyl group-containing polyolefin. Can do.

  Moreover, the epoxy resin composition for sealing is a silane coupling agent such as γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, a flame retardant, a colorant, a silicone flexible agent, etc. Can also be contained.

  The sealing epoxy resin composition is, for example, mixed with the above-mentioned raw material with a mixer, blender, etc., then melt-kneaded with a kneader, a heating roll, etc. It is obtained by making. If necessary, a tablet-like epoxy resin composition for sealing may be obtained by tableting a powdery epoxy resin composition for sealing.

  The 1% mass loss temperature of the cured epoxy resin composition for sealing is preferably 265 ° C. or higher. The 1% mass reduction temperature means the heating temperature when the mass of the cured product is reduced from that before heating when the cured product is heated, and the amount of decrease is 1% of the mass before heating.

  The 1% mass loss temperature is measured by the following method. First, a cured product is obtained by heating the epoxy resin composition for sealing on a hot plate at 130 ° C. for 5 minutes. This cured product is subjected to a post-curing treatment by heating at 130 ° C. for 2 hours. Subsequently, the cured product after the post-curing treatment was subjected to a temperature increase condition of 20 ° C./min in an air atmosphere using a differential thermothermal gravimetric simultaneous measurement device (TG-DTA) manufactured by Seiko Instruments Inc. While increasing the temperature from 20 ° C to 1000 ° C, the weight change of the cured product is measured. As a result, the temperature when the weight of the cured product is reduced by 1% by weight relative to the value when the temperature is 20 ° C. is defined as a 1% weight loss temperature.

  Thus, that 1% mass loss temperature of hardened | cured material is 265 degreeC or more means that hardened | cured material has the outstanding thermal stability because there are few volatile components in a high temperature state.

  In addition, for example, in the case of a cured product of a triphenylmethane-based epoxy resin, there is a case where Tg becomes high but a problem that thermal decomposition is likely to occur. This is because, in the case of a cured product of a triphenylmethane-based epoxy resin, since the crosslinking density is high (or the number of crosslinking points per unit volume is large), thermal decomposition of the cured product is likely to start from these crosslinked parts. it is conceivable that.

  On the other hand, in the present embodiment, the cured product of the naphthylene ether skeleton-containing epoxy resin is hardly thermally decomposed. This is because a cured product of an epoxy resin containing a naphthylene ether skeleton has a lower crosslinking density (or fewer crosslinking points per unit volume) than a cured product of a triphenylmethane epoxy resin. It is considered that this is because there are few cross-linked parts that become the starting part of decomposition. For this reason, in this embodiment, the epoxy resin composition for sealing whose 1% mass loss temperature of hardened | cured material is 265 degreeC or more can be obtained.

  The sealing epoxy resin composition according to this embodiment is suitable for producing a sealing material in a single-sided mold type semiconductor device.

  A single-sided mold type semiconductor device is obtained, for example, by forming a sealing material by molding an epoxy resin composition for sealing on one side of a substrate. For example, a semiconductor chip is mounted on one surface of the base material, and the semiconductor chip is sealed with a sealing material. Thereby, for example, a semiconductor device including one or more semiconductor chips and a sealing material formed in a sheet shape on one surface of the semiconductor chip is obtained.

  In forming the sealing material, the sealing epoxy resin composition is preferably molded by a compression molding method. In this case, for example, the substrate is first placed in a compression mold. Then, the epoxy resin composition for sealing is supplied on the single side | surface of the base material in a metal mold | die. Subsequently, the sealing epoxy resin composition is compressed toward the substrate while being heated. Thereby, the sealing material is formed on one side of the substrate by curing the epoxy resin composition for sealing.

  The sealing epoxy resin composition may be molded by an appropriate molding method such as a low-pressure transfer molding method or the like instead of the compression molding method.

  The molding temperature when molding the sealing epoxy resin composition is preferably in the range of 130 to 160 ° C. In this case, since the molding temperature is relatively low, warpage of the semiconductor device can be reduced. In addition, the cured resin contained in the sealing material formed in this embodiment has high flexibility due to the naphthylene ether skeleton, and this can also reduce the warpage of the semiconductor device. . Further, even when the sealing epoxy resin composition is molded at such a low temperature, in this embodiment, the fluidity of the sealing epoxy resin composition at the time of molding is good, so the moldability is good, Furthermore, the uniformity of the sealing material formed from the epoxy resin composition for sealing can be improved and the occurrence of unevenness in the sealing material can be suppressed. More preferably, the molding temperature is in the range of 130 to 140 ° C.

  The base material in the semiconductor device is a wiring board such as a printed wiring board, for example. A semiconductor chip is mounted on one side of the wiring board. By molding the sealing epoxy resin composition on one side of the wiring board, a sealing material can be formed on the wiring board and the semiconductor chip can be sealed with the sealing material. Thereby, a single-sided mold type semiconductor device is obtained.

  The substrate may be made of a wafer such as a silicon wafer. In this case, a wafer level package can be manufactured as a semiconductor device. In this case, for example, an integrated circuit, a rewiring layer, and the like are first formed on one side of the wafer. Subsequently, the sealing epoxy resin composition is formed on one surface of the wafer to produce a sealing material. Bumps connected to the rewiring layer are provided on one side of the wafer. The sealing material seals the integrated circuit, the rewiring layer, and the like except for the position where the bump is provided. Subsequently, a plurality of wafer level packages are obtained by cutting the wafer.

  Thus, also when a base material is a product made from a wafer, when forming a sealing material in a base material in this embodiment, curvature can be suppressed. Therefore, even when a sealing material is formed on a large wafer having a diameter of 12 inches (300 mm), warpage can be suppressed.

  The thickness of the sealing material formed on the substrate is preferably 1.2 mm or less. In this case, warpage of the semiconductor device is particularly suppressed. More preferably, the thickness of the sealing material is in the range of 0.2 to 1.2 mm.

[Preparation of epoxy resin composition for sealing]
In each Example and Comparative Example, the components shown in Table 1 were uniformly mixed using a mixer, and then melt-kneaded while heating at about 100 ° C. using a kneader. The mixture thus obtained was cooled and then pulverized to obtain a powdery epoxy resin composition for sealing. By compressing this powdery epoxy resin composition for sealing, a tablet-like epoxy resin composition for sealing was obtained.

Details of the components shown in Table 1 are as follows.
Epoxy resin A: naphthylene ether skeleton-containing epoxy resin having a structure represented by the formula (1), epoxy equivalent of 218 g / eq, ICI viscosity at 150 ° C. of 0.05 Pa · s, manufactured by DIC, product number EXA7311-G4.
Epoxy resin B: Orthocresol novolac type epoxy resin, manufactured by DIC, product number N663.
Epoxy resin C: crystalline epoxy resin, manufactured by Mitsubishi Chemical, product number YX8800
Epoxy resin D: crystalline epoxy resin, manufactured by Mitsubishi Chemical, product number YX4000H
Imidazole compound (2PZ): 2-phenylimidazole, melting point 137 to 147 ° C., manufactured by Shikoku Chemicals Co., Ltd., product number 2PZ.
-Imidazole compound (2P4MZ): 2-phenyl-4-methylimidazole, melting point 174-184 ° C, manufactured by Shikoku Chemicals Co., Ltd., product number 2P4MZ.
Imidazole compound (2PHZ): 2-phenyl-4,5-dihydroxymethylimidazole, decomposition temperature 230 ° C., manufactured by Shikoku Kasei Kogyo, product number 2PHZ.
-Phenol resin: Product number H-3M manufactured by Meiwa Kasei Co., Ltd.
Spherical fused silica: manufactured by Denki Kagaku Kogyo, product number FB940, average particle size 13 μm.
Mold release agent: carbana wax (manufactured by Dainichi Chemical Co., Ltd., product number F1-100) and oxidized polyethylene wax (manufactured by Dainichi Chemical Co., Ltd., product number PED191).
Silane coupling agent: Shin-Etsu Silicone, product number KBM573.
Carbon black: Product number MA600 manufactured by Mitsubishi Chemical.

[Evaluation test]
(1) Curability evaluation The epoxy resin composition for sealing obtained in each of Examples and Comparative Examples was set in a curastometer VPS type, and torque was measured while heating at 130 ° C. Then, the percentage of the torque when 300 seconds elapsed from the start of heating to the torque when 600 seconds elapsed from the start of heating was calculated. In addition, when this percentage did not reach 50%, it was evaluated as “uncured”.

(2) Appearance and warpage evaluation Using a molding machine (model number CPM-180) manufactured by TOWA, obtained in each Example and Comparative Example on one side of a silicon wafer having a diameter of 12 inches (300 mm) and a thickness of 0.775 μm. A sealing material having a thickness of 0.5 mm was formed by compression molding the sealing epoxy resin composition under the conditions of a pressure of 6.9 MPa (70 kgf / cm ² ), a temperature of 130 ° C., and a time of 5 minutes.

  The case where the surface of the sealing material is visually observed and the uniform appearance is maintained is “A”, and the surface is uneven, and the case where the unevenness is about 30% of the whole is “ "B", the case where unevenness was observed on the surface and the range where the unevenness occurred exceeded 30% of the whole was evaluated as "C".

  Moreover, the curvature of the silicon wafer was evaluated by the following method. On the flat surface, the silicon wafer was disposed so that the sealing material faced upward. In this state, the center of the upper surface of the sealing material was used as a reference point. In addition, four measurement points were set at the end of the upper surface of the sealing material. These measurement points were set at intersections between two virtual lines intersecting in a cross shape at the center of the sealing material and the end of the upper surface of the sealing material. The Z-axis dimension (height dimension) between the flat surface and the reference point and the Z-axis dimension (height dimension) between the flat surface and each measurement point were measured. For measurement of the Z-axis dimension, a differential interference microscope (MM-40) manufactured by Nikon Corporation was used. The value obtained by subtracting the value of the Z-axis dimension of the reference point from the average value of the Z-axis dimension of the four measurement points was taken as the value of warpage.

(3) 1% mass loss temperature evaluation The cured epoxy resin composition obtained in each Example and Comparative Example was heated on a hot plate at 130 ° C. for 5 minutes to obtain a cured product. This cured product was subjected to a post-curing treatment by heating at 130 ° C. for 2 hours. Subsequently, the cured product after the post-curing treatment was subjected to a temperature increase condition of 20 ° C./min in an air atmosphere using a differential thermothermal gravimetric simultaneous measurement device (TG-DTA) manufactured by Seiko Instruments Inc. While raising the temperature from 20 ° C. to 1000 ° C., the change in the weight of the cured product was measured. As a result, the temperature when the weight of the cured product was reduced by 1% by weight relative to the value at 20 ° C. was defined as a 1% weight loss temperature.

(4) Comprehensive evaluation Based on the result of the evaluation test, a comprehensive evaluation of the performance of the epoxy resin composition for sealing was performed. It evaluated with A, B, and C in order from the outstanding thing.

  The above results are shown in Tables 1 and 2.

  In Examples 1 to 8, even when the sealing epoxy resin composition was molded at a low temperature, the curability was good. Moreover, the sealing material with a favorable external appearance was obtained by compression-molding the epoxy resin composition for sealing at low temperature, and the warpage of the wafer was small.

  On the other hand, in Comparative Examples 1 and 2, unevenness occurred in the sealing material, and a large warp occurred. Further, in Comparative Examples 3, 4 and 9, even when the sealing epoxy resin composition was molded at a low temperature, it could not be cured, and therefore the appearance and warpage could not be evaluated. In Comparative Examples 5 to 8, large warpage occurred.

[Thickness dependency evaluation]
Using a molding machine (model number CPM-180) manufactured by TOWA, the epoxy resin composition for sealing obtained in Example 2 was pressed on one side of a silicon wafer having a diameter of 12 inches (300 mm) and a thickness of 0.775 μm. The sealing material was formed by compression molding under conditions of 6.9 MPa (70 kgf / cm ² ), temperature 130 ° C., and time 5 minutes.

  By the above method, a plurality of samples having different sealing material thicknesses of 0.15 mm to 1.50 mm were obtained.

  The samples having different thicknesses were evaluated for curability, appearance, and warpage.

  In the evaluation of curability, a curing characteristic test was performed using a curastometer VPS type. The cured state was judged based on the torque value of the curast meter, and the state where the torque value was almost constant was determined as the cured state. “A” indicates that the whole is fully cured at a curing time of 5 minutes and no undercured portion is observed, “B” indicates that the portion is insufficiently cured at a curing time of 5 minutes, and “B” indicates that the insufficiently cured portion is observed. The case where a partially insufficiently cured portion was observed in 5 minutes was evaluated as “C”. Further, when the number of samples used for the test was increased in consideration of the variation between samples, the case of “A” and the case of “B” were evaluated as “A to B”. In the case of “A to B”, it is considered possible to obtain an evaluation of “A” by optimizing various conditions.

  In the appearance evaluation, a plurality of areas with dimensions of 2 cm × 2 cm are set on the surface of the sealing material, and the tester observes each area with the naked eye while irradiating each area with light from an oblique direction. Based on the result, the difference in gloss was judged. As a result, the case where the non-glossy part is less than 10% of the total area and the area where the gloss is observed is 90% or more is “A”, the ratio of the non-glossy part is 10% to 40% of the total area, The case where the area where gloss is observed is 0% to 90% is “B”, the ratio of the non-gloss portion is 50% to 100% of the total area, and the area where gloss is observed is 50% or less. C ".

  The warpage was evaluated in the same manner as the warpage shown in Tables 1 and 2. As a result, the case where the warp value was less than 2.0 mm was evaluated as “A”, the case where the warp value was 2.0 mm or more and less than 3.0 mm was evaluated as “B”, and the case where the warp value was 3.0 mm or more was evaluated as “C”. Further, when the number of samples used for the test was increased in consideration of the variation between samples, the case of “A” and the case of “B” were evaluated as “A to B”.

  According to this result, particularly in the case where the thickness of the sealing material is within a range of 1.2 to 0.2 mm, the appearance, warpage, and curability evaluation were all excellent.

Claims (13)

Contains epoxy resin, curing agent and inorganic filler,
The epoxy resin is composed of two or more compounds represented by the following general formula (1), and contains a naphthylene ether skeleton-containing epoxy resin having an ICI viscosity at 150 ° C. of 0.1 Pa · s or less,
Two R ^{1 s} in the formula (1) each independently represent a hydrogen atom or a methyl group, and a plurality of R ^{2 s} are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aralkyl group, or a naphthalene group. , A glycidyl ether group-containing naphthalene group, or a glycidyl ether group-containing phenyl group, and n is a number of 1 or more,
The curing agent contains an imidazole compound ,
Molded by compression molding method,
An epoxy resin composition for sealing. Contains phenolic resin,
The epoxy resin composition for sealing according to claim 1, wherein an equivalent ratio of the epoxy resin to the phenol resin is 2.0 or more. The epoxy resin composition for sealing according to claim 1 or 2, wherein the imidazole compound has a melting point in the range of 100 to 185 ° C. The epoxy resin composition for sealing according to any one of claims 1 to 3, wherein a percentage of the epoxy resin containing the naphthylene ether skeleton with respect to the total amount of the epoxy resin composition for sealing is in the range of 3 to 49 mass%. object. 5. The sealing epoxy resin composition according to claim 1, wherein a percentage of the inorganic filler with respect to the total amount of the sealing epoxy resin composition is in a range of 50 to 93 mass%. The epoxy resin composition for sealing according to any one of claims 1 to 5, wherein a percentage of the imidazole compound to the epoxy resin is in a range of 1.2 to 6.2 mass%. The epoxy resin composition for sealing according to any one of claims 1 to 6, wherein an average particle diameter of the inorganic filler is in a range of 2 to 20 µm. The epoxy resin composition for sealing according to any one of claims 1 to 7, wherein a 1% mass loss temperature of a cured product of the epoxy resin composition for sealing is 265 ° C or higher. A substrate;
Covering one side of said substrate, Ri Do a cured product of the sealing epoxy resin composition according to any one of claims 1 to 8, molded in a compression molding the epoxy resin composition for sealing A semiconductor device provided with the sealing material formed by this . The semiconductor device according to claim 9, wherein the substrate is made of a wafer. The semiconductor device according to claim 9, wherein the base material is a wiring board, a semiconductor chip is mounted on the one surface of the base material, and the semiconductor chip is sealed with the sealing material. The semiconductor device according to any one of claims 9 to 11 thickness before Kifutomezai is 1.2mm or less. One or more semiconductor chips, and a sealing material made of a cured product of the sealing epoxy resin composition according to any one of claims 1 to 8, formed in a sheet shape on one surface of the semiconductor chip. A semiconductor device comprising: