JP2016222853A - Resin composition for encapsulation, semiconductor device and production method of resin composition for encapsulation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for encapsulation which contains an imidazole compound and nonetheless has good storage stability and curability.SOLUTION: The present invention is a resin composition for encapsulation. It contains an epoxy resin, a phenolic curing agent, an inorganic filler and an imidazole compound. The imidazole compound has a melting point of 160°C or more and less than 230°C and has an alkyl group at 2-position and an alkyl group having a hydroxyl group at at least one of 4- and 5-position.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an encapsulating resin composition, a semiconductor device produced using the encapsulating resin composition, and a method for producing the encapsulating resin composition.

  Conventionally, with respect to sealing semiconductor elements such as transistors and ICs, resin sealing has been performed from the viewpoint of improving productivity and reducing costs. Resin sealing is performed by molding a sealing resin composition containing, for example, an epoxy resin, a phenol resin-based curing agent, a curing accelerator, and an inorganic filler as essential components to obtain a sealing material.

  In obtaining a sealing material, an epoxy resin composition for semiconductor sealing containing an epoxy resin, a phenol resin-based curing agent, an imidazole-based curing catalyst, and an inorganic filler has been proposed. It has been proposed to use phenylimidazole type and benzimidazole type compounds as imidazole-based curing catalysts for epoxy resin compositions for semiconductor encapsulation (see Patent Document 1).

JP 2014-019717 A

  However, the imidazole-based curing catalyst as in Patent Document 1 tends to hardly dissolve in the epoxy resin composition for semiconductor encapsulation. If the imidazole-based curing catalyst is difficult to dissolve in the composition, it tends to cause a decrease in storage stability and a decrease in curability of the composition. For this reason, it may not be possible to meet recent demands for improving productivity.

  This invention is made | formed in view of the said reason, and it aims at providing the resin composition for sealing with favorable storage stability and sclerosis | hardenability, containing an imidazole compound. In addition, it is another object of the present invention to provide a semiconductor device capable of improving reliability by including a sealing material obtained by curing the sealing resin composition. It is another object of the present invention to provide a production method for obtaining an encapsulating resin composition having good storage stability and curability while containing an imidazole compound.

  One aspect of the present invention is a sealing resin composition, which contains an epoxy resin, a phenolic curing agent, an inorganic filler, and an imidazole compound, and the imidazole compound has a melting point of 160 ° C. The temperature is lower than 230 ° C., and the alkyl group is provided at the 2-position and the alkyl group having a hydroxyl group is provided at at least one of the 4- and 5-positions.

  One embodiment of the present invention is a semiconductor device including a semiconductor element and a sealing material that seals the semiconductor element, and the sealing material is a cured product of the sealing resin composition.

  One aspect of the present invention is a method for producing a resin composition for sealing, which comprises heating and kneading an epoxy resin, a phenolic curing agent, an inorganic filler, and an imidazole compound, and the imidazole compound Has a melting point of 160 ° C. or higher and lower than 230 ° C., and has an alkyl group at the 2nd position and an alkyl group having a hydroxyl group at at least one of the 4th and 5th positions.

  According to the present invention, it is possible to obtain an encapsulating resin composition having good curability and storage stability while containing an imidazole compound. By including both the imidazole compound and the phenolic curing agent, the reliability such as the electrical characteristics of the sealing material can be improved. The reliability of the semiconductor device can be improved by providing a sealing material obtained by curing the sealing resin composition.

It is a schematic sectional drawing which shows the semiconductor device which concerns on one Embodiment of this invention.

  The sealing resin composition according to the present embodiment contains an epoxy resin, a phenolic curing agent, an inorganic filler, and an imidazole compound.

  The sealing resin composition is suitable for sealing the semiconductor element 50, for example, as shown in FIG. 1 includes a metal lead frame 53, a semiconductor element 50 mounted on the lead frame 53, a wire 56 that electrically connects the semiconductor element 50 and the lead frame 53, and a semiconductor. And a sealing material 62 that seals the element 50.

  The imidazole compound has a melting point of 160 ° C. or higher and lower than 230 ° C., and has an alkyl group at the 2-position and an alkyl group having a hydroxyl group at at least one of the 4- and 5-positions. Therefore, the imidazole compound is easily dispersed and dissolved in the sealing resin composition. For this reason, good storage stability, good fluidity, and good curability can be imparted to the encapsulating resin composition. As described above, the moldability of the sealing resin composition can be improved by improving the curability and fluidity of the sealing resin composition. In addition, since the imidazole compound has an alkyl group at the 2-position, steric hindrance due to the 2-position group can be made difficult to occur during the curing reaction of the sealing resin composition. For this reason, favorable sclerosis | hardenability can be provided to the resin composition for sealing. Moreover, since the resin composition for sealing contains a phenol-type hardening | curing agent with an imidazole compound, the curability excellent in the resin composition for sealing can be provided, suppressing the quantity of an imidazole compound. For this reason, the extraction of chlorine in the epoxy resin by the imidazole compound can be suppressed, and the reliability such as the electrical characteristics of the sealing material 62 can be favorably maintained.

  Hereinafter, the sealing resin composition will be described in detail.

  The melting point of the imidazole compound is 160 ° C. or higher and lower than 230 ° C. For this reason, when preparing the sealing resin composition by heating and kneading the raw materials constituting the sealing resin composition, the imidazole compound can be easily dispersed and dissolved in the sealing resin composition. it can. Thereby, the storage stability of the resin composition for sealing can be improved, and the curability of the resin composition for sealing can also be improved. Moreover, the reactivity at the time of hardening the resin composition for sealing can be improved because melting | fusing point of an imidazole compound is 160 degreeC or more and less than 230 degreeC. Also by this, the curability of the sealing resin composition can be improved. The melting point of the imidazole compound is more preferably in the range of 180 ° C to 220 ° C.

  The imidazole compound is represented, for example, by the following formula (I).

The imidazole compound of formula (I) has R ₁ at the 2-position, R ₂ at the 4-position, and R ₃ at the 5-position. R ₁ is an alkyl group, and at least one selected from the group of R ₂ and R ₃ is preferably an alkyl group having a hydroxyl group.

Since R ₁ is an alkyl group, steric hindrance due to the 2-position group can be made difficult to occur during the curing reaction of the encapsulating resin composition. Furthermore, since R ₁ is an alkyl group, since R ₁ does not have a bulky structure such as a benzene ring, the dispersibility and solubility of the imidazole compound in the sealing resin composition are improved. R ₁ preferably has 1 to 4 carbon atoms, and more preferably R ₁ is an isopropyl group.

Each of R ₂ and R ₃ is hydrogen, an alkyl group, or an alkyl group having a hydroxyl group, and at least one of R ₂ and R ₃ is an alkyl group having a hydroxyl group. Since at least one of R ₂ and R ₃ is an alkyl group having a hydroxyl group, this alkyl group further improves the dispersibility and solubility of the imidazole compound in the sealing resin composition and This hydroxyl group suppresses the compatibility of the imidazole compound with the epoxy resin. Thereby, the preservability of the resin composition for sealing can be improved. In this case, the number of carbon atoms contained in the “alkyl group” can be 1 to 3. The “alkyl group having a hydroxyl group” is also referred to as a hydroxyl alkyl group, for example. Carbon number contained in the alkyl group which has a hydroxyl group can be 1-3.

  Examples of the imidazole compound include 2-propyl-4,5-dihydroxymethylimidazole, 2-isopropyl-4,5-dihydroxymethylimidazole, 2-methyl-4,5-dihydroxymethylimidazole, 2-ethyl-4,5- It can contain at least one compound selected from the group consisting of dihydroxymethylimidazole.

  The imidazole compound preferably includes a plurality of compounds having different melting points. In this case, when the sealing resin composition is heated to mold the sealing material 62, the fluidity and curability of the sealing resin composition can be improved in a balanced manner. It is preferable that the difference between the melting points of the plural kinds of compounds is in the range of 10 to 80 ° C.

  The content of the imidazole compound is, for example, preferably in the range of 0.5 to 20 parts by mass and more preferably in the range of 2 to 15 parts by mass with respect to 100 parts by mass of the epoxy resin. When the imidazole compound is contained within the above range, the curability of the encapsulating resin composition becomes good while maintaining the reliability of the encapsulant 62 well. Thereby, the hardening reaction of the resin composition for sealing can be accelerated. For this reason, the efficiency of obtaining the semiconductor device 1 can be improved. In addition, the storage stability and fluidity of the encapsulating resin composition are also improved. Thereby, it can be made hard to produce that the resin composition for sealing hardens before sealing semiconductor element 50. In the resin composition for sealing, good curability, good fluidity at the time of molding, and good storage stability can be obtained. For this reason, the production efficiency and reliability of the semiconductor device 1 can be improved.

The epoxy resin can contain at least one component selected from the group consisting of, for example, a glycidyl ether type epoxy resin, a glycidyl amine type epoxy resin, a glycidyl ester type epoxy resin, and an olefin oxidation type (alicyclic) epoxy resin. . More specifically, the epoxy resin is, for example, an alkylphenol novolak type epoxy resin such as a phenol novolak type epoxy resin or a cresol novolak type epoxy resin; a naphthol novolak type epoxy resin; a phenol aralkyl type epoxy resin having a phenylene skeleton, a biphenylene skeleton, or the like; Biphenyl aralkyl type epoxy resin; naphthol aralkyl type epoxy resin having phenylene skeleton, biphenylene skeleton, etc .; polyfunctional type epoxy resin such as triphenol methane type epoxy resin and alkyl-modified triphenol methane type epoxy resin; triphenyl methane type epoxy resin; Tetrakisphenol ethane type epoxy resin; dicyclopentadiene type epoxy resin; stilbene type epoxy resin; bisphenol A type epoxy resin, bis Biphenol type epoxy resins such as enol F type epoxy resins; Biphenyl type epoxy resins; Naphthalene type epoxy resins; Alicyclic epoxy resins; Bromine containing epoxy resins such as bisphenol A type bromine containing epoxy resins; Polyamines such as diaminodiphenylmethane and isocyanuric acid One or more components selected from the group consisting of glycidylamine-type epoxy resins obtained by the reaction of glycidylamine-type epoxy resins obtained by the reaction of chloroidin with epichlorohydrin; and polybasic acids such as phthalic acid and dimer acid and epichlorohydrin Can be contained.

  The phenolic curing agent is a curing agent for the sealing resin composition, and is blended in consideration of the physical properties of the sealing material 62, the moldability of the sealing resin composition, and the like. As the phenolic curing agent, a compound that can react with the epoxy resin contained in the sealing resin composition to form a crosslinked structure is used.

  In the present embodiment, the sealing resin composition may further contain an acid anhydride as a curing agent.

  The phenolic curing agent is, for example, a novolak resin such as a phenol novolak resin, a cresol novolak resin, or a naphthol novolak resin; a phenol aralkyl resin having a phenylene skeleton or a biphenylene skeleton; an aralkyl resin such as a naphthol aralkyl resin having a phenylene skeleton or a biphenylene skeleton Polyfunctional phenolic resin such as triphenolmethane type resin; dicyclopentadiene type phenolic resin such as dicyclopentadiene type phenol novolak resin, dicyclopentadiene type naphthol novolac resin; terpene modified phenolic resin; bisphenol A, bisphenol F, etc. It may contain at least one component selected from the group consisting of bisphenol type resins; and triazine-modified novolak resins. In particular, the phenolic curing agent preferably contains at least one of a phenol aralkyl type phenol resin and a biphenyl aralkyl type phenol resin.

  When the epoxy resin and the phenolic curing agent are contained in the sealing resin composition, the equivalent ratio of epoxy group / hydroxyl group in the sealing resin composition is in the range of 0.5 to 1.5. Preferably, it is in the range of 0.9 to 1.5, more preferably in the range of 1.0 to 1.3.

  The inorganic filler can contain at least one component selected from the group consisting of fused silica such as fused spherical silica, crystalline silica, alumina, and silicon nitride. The thermal expansion coefficient of the sealing material 62 can be adjusted by including an inorganic filler in the sealing resin composition. In particular, the inorganic filler preferably contains fused silica. In this case, high filling property of the inorganic filler in the sealing resin composition and high fluidity of the sealing resin composition at the time of molding can be obtained. It is also preferable that the inorganic filler contains at least one component selected from the group consisting of alumina, crystalline silica, and silicon nitride. In this case, high thermal conductivity of the sealing material 62 can be obtained.

  The average particle size of the inorganic filler is, for example, in the range of 0.2 to 70 μm. When the average particle size is in the range of 0.5 to 20 μm, particularly good fluidity can be obtained at the time of molding the sealing resin composition. The average particle diameter is a volume-based median diameter calculated from the measured value of the particle size distribution by the laser diffraction / scattering method, and is obtained using a commercially available laser diffraction / scattering particle size distribution measuring apparatus.

  The inorganic filler may contain two or more components having different average particle diameters in order to adjust the viscosity of the sealing resin composition during molding, the physical properties of the sealing material 62, and the like.

  The inorganic filler is preferably in the range of 60 to 93 mass% with respect to the total amount of the sealing resin composition. If the amount of the inorganic filler is too small, the linear expansion coefficient of the sealing material 62 increases, so that the warp of the semiconductor device 1 during reflow may increase. On the other hand, when there are too many inorganic fillers, sufficient fluidity | liquidity of the resin composition for sealing may not be ensured, and a wire sweep may become large at the time of shaping | molding.

  The resin composition for sealing may contain a coupling agent. The coupling agent can contribute to improving the affinity between the inorganic filler and the thermosetting resin component and improving the adhesion of the sealing material 62 to the lead frame 53.

  The coupling agent can contain at least one component selected from the group consisting of, for example, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, and an aluminum / zirconium coupling agent. Examples of the silane coupling agent include glycidoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; N From the group consisting of aminosilanes such as -β (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane; alkylsilanes; ureidosilanes; It can contain at least one selected component.

  The coupling agent is preferably in the range of 0.1 to 2.0 mass% with respect to the total amount of the inorganic filler and the coupling agent. In this case, the adhesion between the sealing material 62 and the lead frame 53 is particularly high.

  The sealing resin composition may contain additives other than the above components as long as the effects of the present embodiment are not impaired. Examples of the additive include a release agent, a flame retardant, a colorant, a stress reducing agent, and an ion trapping agent.

  The mold release agent may contain at least one component selected from the group consisting of carnauba wax, stearic acid, montanic acid, carboxyl group-containing polyolefin, ester wax, oxidized polyethylene, and metal soap, for example.

  The flame retardant can contain, for example, at least one component selected from the group consisting of magnesium hydroxide, aluminum hydroxide, and red phosphorus.

  The colorant can contain, for example, at least one component selected from the group consisting of carbon black, bengara, titanium oxide, phthalocyanine, and perylene black.

  The stress reducing agent can contain, for example, at least one component selected from the group consisting of silicone elastomers, silicone resins, silicone oils, and butadiene rubbers. The butadiene-based rubber can contain at least one component of, for example, methyl acrylate-butadiene-styrene copolymer and methyl methacrylate-butadiene-styrene copolymer.

  The ion trapping agent can contain, for example, at least one of a hydrotalcite compound and a hydrated oxide of a metal element. The hydrous oxide of the metal element can contain at least one component selected from the group consisting of, for example, a hydrous oxide of aluminum, a hydrous oxide of bismuth, a hydrous oxide of titanium, and a hydrous oxide of zirconium. .

  In producing a sealing resin composition, a powdery imidazole compound is prepared. It is preferable that the powdery imidazole compound can pass through a sieve having an opening of 250 μm. In this case, the imidazole compound is particularly dispersed and easily dissolved in the sealing resin composition. It is also preferable that the imidazole compound can pass through a sieve having an opening of 212 μm. The sieve is produced according to JIS Z 8801.

  It is also preferred that the powdery imidazole compound has an average particle size in the range of 3 to 50 μm. In this case, the imidazole compound is particularly dispersed and easily dissolved in the sealing resin composition. The average particle size of the imidazole compound is measured by a laser diffraction / scattering method.

  A resin composition for sealing can be obtained by heating and kneading and mixing a raw material containing a powdery imidazole compound. More specifically, for example, a raw material containing a thermosetting component, an inorganic filler, and a powdery imidazole compound is mixed with a mixer, a blender or the like until sufficiently uniform, and then a kneader such as a heat roll or a kneader. The raw material is melt-mixed while being heated by heating, and then cooled to room temperature. The temperature at which the raw materials are heated and kneaded is preferably in the range of 80 ° C to 120 ° C.

  By pulverizing the mixture obtained as described above by a known means, a powdery sealing resin composition can be produced. In this case, the thermosetting component can include an epoxy resin and a phenolic curing agent. The encapsulating resin composition may not be in powder form, and may be in tablet form, for example. The encapsulating resin composition in the tablet form preferably has dimensions and mass suitable for molding conditions.

  The spiral flow length at 170 ° C. of the encapsulating resin composition is preferably 40 to 300 cm, and more preferably 100 to 300 cm. In this case, non-filling of the sealing material 62 due to deterioration of the fluidity of the sealing resin composition at the time of molding, so-called weld void is less likely to occur. In addition, the wire 56 connecting the semiconductor element 50 and the lead frame 53 is less likely to be damaged during molding. The spiral flow length of the encapsulating resin composition can be controlled by appropriately setting the composition of the encapsulating resin composition within the range of the present embodiment.

  The gel time of the encapsulating resin composition is preferably 10 to 100 seconds, and more preferably 15 to 80 seconds. In this case, the molding cycle for producing the sealing material 62 is particularly short, and the productivity of the semiconductor device 1 is particularly high. The gel time was measured when the torque was measured using a curast meter VPS type manufactured by JSR Trading Co., Ltd. while heating the sealing resin composition at 170 ° C. It is defined as the time required to reach .81 (N / m).

  An example of the semiconductor device 1 including the sealing material 62 manufactured from the sealing resin composition and a method for manufacturing the semiconductor device 1 will be described.

  The package form of the semiconductor device 1 is, for example, an insertion type package such as Mini, D pack, D2 pack, To22O, To3P, dual in-line package (DIP), quad flat package (QFP), small outline package, etc. (SOP), small outline J-lead package (SOJ), etc.

  FIG. 1 shows a cross-sectional view of a semiconductor device 1 in the present embodiment. The semiconductor device 1 includes a metal lead frame 53, a semiconductor element 50 mounted on the lead frame 53, a wire 56 that electrically connects the semiconductor element 50 and the lead frame 53, and the semiconductor element 50. And a sealing material 62 to be stopped.

  In the present embodiment, the lead frame 53 includes a die pad 58, inner leads 521, and outer leads 522. The lead frame 53 can be formed of a metal material mainly including an iron alloy such as 42 alloy or copper, for example.

  The semiconductor element 50 is fixed on the die pad 58 of the lead frame 53 with an appropriate die bonding material 60. As a result, the semiconductor element 50 is mounted on the lead frame 53. The semiconductor element 50 is, for example, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, or a solid-state imaging element. The semiconductor element 50 may be a new power device such as SiC or GaN.

  Subsequently, the semiconductor element 50 and the inner lead 521 in the lead frame 53 are connected by a wire 56. The wire 56 may be made of gold, but may include at least one of silver and copper.

  Subsequently, the sealing resin composition is molded and cured. Thereby, the sealing resin composition becomes the sealing material 62 for sealing the semiconductor element 50. By including both the phenolic curing agent and the imidazole compound, the sealing resin composition can improve reliability such as electrical characteristics in the sealing material 62 as described above.

  In manufacturing the semiconductor device 1, the semiconductor element 50 is mounted on a substrate other than the lead frame 53 and then the sealing resin composition is molded and cured to seal the semiconductor element 50. May be provided. An example of the substrate is a PBGA (Plastic Ball Grid Array) substrate.

  It is preferable to produce the sealing material 62 by molding the sealing composition by a pressure molding method. The pressure molding method is, for example, an injection molding method, a transfer molding method, or a compression molding method.

  The molding pressure when molding the sealing resin composition by pressure molding is preferably 3.0 MPa or more, and the molding temperature is preferably 120 ° C. or more. In this case, it is possible to obtain the semiconductor device 1 in which the semiconductor element 50 is sealed with the uniform sealing material 62 with less filling, so-called weld voids and internal voids.

  When the semiconductor device 1 is molded by the transfer molding method, the injection pressure of the sealing resin composition into the mold is preferably 3 MPa or more, and more preferably in the range of 4 to 710 MPa. Moreover, it is preferable that heating temperature (mold temperature) is 120 degreeC or more, and if it exists in the range of 160-190 degreeC, it is still more preferable. The heating time is preferably in the range of 30 to 300 seconds, and more preferably in the range of 60 to 180 seconds.

  In the transfer molding method, after the sealing material 62 is manufactured in a mold, the sealing material 62 is heated with the mold closed and post-curing is performed, and then the mold is opened and the semiconductor is opened. The device 1 is preferably removed. The heating conditions for post-curing are, for example, a heating time in the range of 160 to 190 ° C. and a heating time in the range of 2 to 8 hours.

  When the semiconductor device 1 is molded by the transfer molding method, the compression pressure is preferably 3 MPa or more, and more preferably within the range of 5.0 to 10 MPa. The heating temperature (mold temperature) is preferably 120 ° C. or higher, and more preferably in the range of 150 to 185 ° C. The heating time is preferably in the range of 60 to 300 seconds.

  Hereinafter, the present invention will be specifically described by way of examples.

<Preparation of sealing resin composition>
In each of Examples and Comparative Examples, the components shown in the following table were blended, mixed and dispersed uniformly with a mixer, heated and kneaded with a kneader at 100 ° C., and the resulting mixture was cooled and pulverized. The powder obtained in this manner was tableted to obtain a tablet-like sealing resin composition.

The details of the components shown in the table are as follows.
・ Inorganic filler: Spherical fused silica Electrochemical industry FB910
Silane coupling agent: 3-mercaptopropyltrimethoxysilane (Shin-Etsu Silicone KBM802).
Epoxy resin: biphenyl type epoxy resin (Mitsubishi Chemical make, product number YX4000, epoxy equivalent 186).
-Phenolic curing agent: biphenyl aralkyl resin (Maywa Kasei, product number MEH-7851SS).
-Mold release agent: Carnauba wax.
Curing accelerator 1-1: 2-isopropyl-4,5-dihydroxymethylimidazole (manufactured by Nippon Synthetic Chemical Industry, melting point: 191 ° C.); passed through a sieve having an opening of 250 μm.
Curing accelerator 1-2: 2-isopropyl-4,5-dihydroxymethylimidazole (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.); passed through a sieve having an opening of 212 μm.
Curing accelerator 2: 2-methyl-4,5-dihydroxymethylimidazole (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., melting point: 173 ° C.); passed through a sieve having an opening of 250 μm.
Curing accelerator 3: 2-ethyl-4,5-dihydroxymethylimidazole (melting point: 180 ° C.); passed through a sieve having an opening of 250 μm.
Curing accelerator 4: 2-phenyl-4,5-dihydroxymethylimidazole (product number 2PHZ, melting point: 230 ° C., manufactured by Shikoku Kasei Kogyo Co., Ltd.); passed through a sieve having an opening of 250 μm.
Pigment: Mitsubishi Chemical, product number MA600.

<Evaluation test>
The following evaluation tests were performed on the sealing resin compositions obtained in the respective Examples and Comparative Examples, and the semiconductor devices manufactured using the respective sealing resin compositions. These results will be described later. It is shown in the table.

(1) Gel Time Torque was measured while heating the sealing resin composition at 170 ° C. using a curast meter VPS type manufactured by JSR Trading Co., Ltd. The time required from the start of heating until the measured torque value reached 9.81 (N / m) was investigated, and this time was defined as the gel time. Furthermore, the gel time thus obtained was used as an index of curability of the sealing resin composition.

(2) Gel time retention The gel time of the sealing resin composition was measured after standing at a temperature of 30 ° C. for 48 hours. The percentage of gel time after standing with respect to the gel time immediately after production was defined as the gel time retention rate. This gel time retention rate was used as one index for investigating the storage stability of the sealing resin composition.

(3) Evaluation of Gel Time Retention Rate A case where the gel time retention rate was 95% or higher was evaluated as “◯”, a case where it was 85 to 94% was evaluated as “Δ”, and a case where it was 84% or lower was evaluated as “X”.

(4) Spiral flow As an index of fluidity at the time of molding, the spiral flow length of the epoxy resin composition for sealing immediately after production in each example and comparative example is used as a spiral flow measuring die in accordance with ASTM D3123. The mold temperature was 170 ° C., the injection pressure was 6.9 MPa, and the molding time was 120 seconds. The spiral flow length thus obtained was used as an indicator of the fluidity of the sealing resin composition.

(5) Spiral flow retention rate The sealing resin compositions in the examples and comparative examples were allowed to stand at a temperature of 30 ° C for 48 hours, and then the spiral flow length of the sealing resin composition was measured. The percentage of the spiral flow length after standing with respect to the spiral flow length immediately after production was defined as the spiral flow retention rate. This spiral flow retention was used as another index for investigating the storage stability of the sealing resin composition.

(6) Evaluation of spiral flow retention rate The case where the spiral flow retention rate was 75% or more was evaluated as “◯”, the case where it was 65 to 74% was evaluated as “Δ”, and the case where it was 65% or less was evaluated as “x”.

(7) Evaluation of undissolved residue One side of the tablet obtained in each Example and Comparative Example was polished 8 times by 2 mm. Every time polishing was performed, the polished surface was observed with a metal microscope. As a result, the case where the undissolved residue of the curing accelerator was never recognized on the polished surface was evaluated as “◯”, and the case where the undissolved residue of the curing accelerator was observed even once on the polished surface was evaluated as “X”.

(8) Evaluation of Semiconductor Device A semiconductor element was mounted on a PBGA substrate having an outer dimension of 35 mm × 35 mm, and the semiconductor element and the PBGA substrate were connected by a gold wire having a diameter of 20 μm and a length of 5 mm. And the semiconductor element was arrange | positioned inside a metal mold | die and the sealing material was produced with the transfer molding method. The mold was heated to 170 ° C., and the sealing resin compositions of Examples and Comparative Examples were supplied into the mold at an injection pressure of 6.9 MPa. The amount of deformation (maximum deformation amount) of the gold wire was confirmed by the flow of the sealing resin composition during molding, and the deformation rate (maximum deformation amount / wire length) of the gold wire was calculated. This deformation rate is shown in the column of “initial deformation rate”. For the sealing resin composition after standing at 30 ° C. for 48 hours, the deformation rate of the gold wire was calculated in the same procedure as described above. This deformation rate is shown in the column of “deformation rate after 30 hours at 30 ° C.”.

  From the results in Table 1, the curing accelerator (imidazole compound) remained undissolved in the encapsulating resin compositions of Comparative Examples 1 and 2, but the encapsulating resin composition of Example 1-11 had no curing accelerator. It didn't melt away. In the sealing resin compositions of Examples 1-5, 7-9 and 10, particularly good gel time evaluation results were obtained. In addition, in the sealing resin compositions of Examples 1, 3-5, and 6, particularly favorable spiral flow evaluation results were obtained. On the other hand, in Comparative Examples 1 and 2, it was found that the retention rate (storage stability) tends to decrease from the results of both gel time and spiral flow. The sealing resin composition of Example 1-7 was compared both in the case of using the sealing resin composition immediately after production and in the case of using the sealing resin composition after standing at 30 ° C. for 48 hours. It was found that the sealing material can be formed by making the gold wire harder to deform than those in Examples 1 and 2.

DESCRIPTION OF SYMBOLS 1 Semiconductor device 50 Semiconductor element 62 Sealing material

Claims (6)

Contains an epoxy resin, a phenolic curing agent, an inorganic filler, and an imidazole compound,
The imidazole compound has a melting point of 160 ° C. or higher and lower than 230 ° C., and has an alkyl group at the 2nd position and an alkyl group having a hydroxyl group at at least one of the 4th and 5th positions.   The sealing resin composition according to claim 1, wherein the alkyl group at the 2-position has 1 to 4 carbon atoms.   The sealing resin composition according to claim 1, wherein the alkyl group at the 2-position is an isopropyl group.   The sealing resin composition according to claim 1, wherein the imidazole compound includes a plurality of compounds having different melting points. A semiconductor element;
A sealing material for sealing the semiconductor element,
A semiconductor device in which the encapsulant is a cured product of the encapsulating resin composition according to any one of claims 1 to 4. Including heat-kneading an epoxy resin, a phenolic curing agent, an inorganic filler, and an imidazole compound,
The above-mentioned imidazole compound has a melting point of 160 ° C. or higher and lower than 230 ° C., and a sealing resin composition comprising an alkyl group at the 2-position and a hydroxyl group-containing alkyl group at the 4-position or 5-position. Method.

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