Encapsulating resin composition and semiconductor device

Abstract

The present invention provides a encapsulating resin composition that yields a cured product with excellent tracking resistance and low elastic modulus. [Solution] The encapsulating resin composition contains an epoxy compound (A), a phenol compound (B), and a filler (C). The filler (C) includes a silicone resin filler (c1). The silicone resin filler (c1) includes a constituent unit having a cyclic siloxane structure represented by formula (1). Si n O 2n R n ...(1) n is an integer between 3 and 5 (inclusive), and R is independently H, CH3, or CH2CH3.

Description

[Technical Field]

[0001] This disclosure generally relates to encapsulating resin compositions and semiconductor devices, and more particularly to encapsulating resin compositions usable for producing encapsulated portions in semiconductor devices and semiconductor devices comprising encapsulated portions including cured products of the encapsulating resin composition. [Background technology]

[0002] Patent Document 1 discloses a semiconductor encapsulation resin composition containing an epoxy resin, a curing agent, an inorganic filler, and a curing accelerator, wherein isocyanurate triglycidyl is used as the epoxy resin and a novolac-type phenol resin having a dicyclopentadiene skeleton is used as the curing agent. This semiconductor encapsulation resin composition is disclosed to have excellent tracking resistance of the cured product. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2006-36939 [Overview of the project] [Problems that the invention aims to solve]

[0004] Increasing the proportion of inorganic fillers in semiconductor encapsulation resin compositions can improve the tracking resistance of cured semiconductor encapsulation resin compositions. However, increasing the proportion of inorganic fillers leads to an excessively high elastic modulus of the cured material. In this case, there is a problem that the encapsulation portion made from the semiconductor encapsulation resin composition becomes more prone to delamination.

[0005] The object of this disclosure is to provide a encapsulating resin composition and a semiconductor device that can yield a cured product with excellent tracking resistance and low elastic modulus. [Means for solving the problem]

[0006] A sealing resin composition according to one aspect of the present disclosure contains an epoxy compound (A), a phenol compound (B), and a filler (C). The filler (C) includes a silicone resin filler (c1). The silicone resin filler (c1) includes a constituent unit having a cyclic siloxane structure represented by formula (1).

[0007] Si n O 2n R n ...(1) n is an integer between 3 and 5 (inclusive), and R is independently H, CH3, or CH2CH3.

[0008] A semiconductor device according to one aspect of the present disclosure comprises a semiconductor element and a sealing portion that seals the semiconductor element. The sealing portion includes a cured product of the sealing resin composition. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a encapsulating resin composition that can yield a cured product with excellent tracking resistance and low elastic modulus. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic cross-sectional view of an example of a semiconductor device according to an embodiment of the present disclosure. [Figure 2] Figure 2 is a schematic cross-sectional view of another example of a semiconductor device in the embodiments of this disclosure. [Modes for carrying out the invention]

[0011] Embodiments will now be described. Note that the embodiments described below are only a selection of the various embodiments of this disclosure. The embodiments described below can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure are achieved. While mechanisms of action and effect may be described below, these mechanisms are all inferred, and this disclosure is not bound by the descriptions of mechanisms.

[0012] 1. Overview The sealing resin composition according to the embodiment (hereinafter also referred to as composition (X)) contains an epoxy compound (A), a phenol compound (B), and a filler (C). The filler (C) includes a silicone resin filler (c1). The silicone resin filler (c1) includes a constituent unit having a cyclic siloxane structure represented by formula (1).

[0013] Si n O 2n R n ...(1) n is an integer between 3 and 5 (inclusive), and R is independently H, CH3, or CH2CH3.

[0014] The inventors have found that, with respect to a semiconductor encapsulation composition containing an epoxy compound (A), a phenol compound (B), and a filler (C), a cured product with excellent tracking resistance and low elastic modulus can be obtained by incorporating a silicone resin filler (c1) having a specific composition and structure into the filler (C).

[0015] The silicone resin filler (c1) may have moderately high water repellency. Therefore, the water repellency of the surface of the cured product can be enhanced, and as a result, the tracking resistance of the cured product can be easily improved. Furthermore, the cyclic siloxane structure of the silicone resin filler (c1) is moderately flexible and deformable. Therefore, the cured product of composition (X) containing the silicone resin filler (c1) may have a low modulus of elasticity. For these reasons, the silicone resin filler (c1) can achieve excellent tracking resistance and a low modulus of elasticity in the cured product.

[0016] From the composition (X) according to the embodiment, a cured product with excellent tracking resistance and low elastic modulus can be obtained. Therefore, the composition (X) is suitably applied to create a sealing portion for encapsulating semiconductor elements, and the sealing portion is less likely to peel off due to the heat generated by the semiconductor elements in the semiconductor device. In other words, composition (X) is useful as a composition for encapsulating semiconductor devices, and in particular as a composition for encapsulating semiconductor devices that have semiconductor elements that generate a large amount of heat.

[0017] 2. Resin Composition for Sealing 2.1 Components The components contained in the composition (X) will be described. In an embodiment, the composition (X) contains an epoxy compound (A), a phenol compound (B), and a filler (C). The epoxy compound (A) and the phenol compound (B) are included in the resin component. The resin component is a component that cures by heating in the composition (X).

[0018] (Epoxy Compound) As described above, the composition (X) contains an epoxy compound (A) as a resin component. The epoxy compound (A) is a compound having an epoxy group. Therefore, the epoxy compound (A) can impart thermosetting properties to the composition (X). The epoxy compound (A) includes, for example, at least one selected from the group consisting of monomers, oligomers, prepolymers, and polymers. The epoxy compound (A) preferably includes a compound having two or more epoxy groups in one molecule.

[0019] Epoxy compound (A) is, for example, alkylphenol novolac type epoxy resins such as phenol novolac type epoxy resins and cresol novolac type epoxy resins; naphthol novolac type epoxy resins; phenol aralkyl type epoxy resins having a phenylene skeleton, biphenylene skeleton, etc.; biphenyl type epoxy resins; biphenyl aralkyl type epoxy resins; naphthol aralkyl type epoxy resins having a phenylene skeleton, biphenylene skeleton, etc.; naphthylene ether type epoxy resins; polyfunctional aromatic epoxy resins such as triphenolmethane type epoxy resins and alkyl-modified triphenolmethane type epoxy resins; triphenylmethane type epoxy resins; tetramethyl It includes at least one selected from the group consisting of sphenolethane type epoxy resins; dicyclopentadiene type epoxy resins; stilbene type epoxy resins; bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin; naphthalene type epoxy resins; alicyclic epoxy resins; brome-containing epoxy resins such as bisphenol A type brome-containing epoxy resin; glycidylamine type epoxy resins obtained by the reaction of polyamines such as diaminodiphenylmethane and isocyanuric acid with epichlorohydrin; and glycidyl ester type epoxy resins obtained by the reaction of polybasic acids such as phthalic acid and dimer acid with epichlorohydrin.

[0020] (Maleimide compounds) The composition (X) preferably further contains a maleimide compound (D) as a resin component. In this case, the tracking resistance of the cured product can be further improved. The exact reason why the maleimide compound (D) can further improve the tracking resistance of the cured product has not been precisely clarified, but it is presumed to be due to the following reasons. The maleimide compound (D) may contain nitrogen atoms in its molecule. Therefore, the proportion of carbon atoms in the maleimide compound (D) can be reduced. In this case, even if the cured product is heated by applying a voltage, the cured product becomes less likely to carbonize. This further improves the tracking resistance of the cured product.

[0021] The maleimide compound (D) is not particularly limited as long as it is a compound having one or more maleimide groups in one molecule, but examples include monomaleimide compounds having one maleimide group in one molecule and polymaleimide compounds having two or more maleimide groups in one molecule. It is preferable that the maleimide compound (D) contains a bismaleimide compound, in which case the tracking resistance of the cured product can be further improved. Examples of monomaleimide compounds include N-phenylmaleimide and N-hydroxyphenylmaleimide. Examples of polymaleimide compounds include bis(4-maleimidophenyl)methane, 2,2-bis{4-(4-maleimidophenoxy)-phenyl}propane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, bis(3,5-dimethyl-4-maleimidophenyl)methane, bis(3,5-diethyl-4-maleimidophenyl)methane, m-phenylenebismaleimide, 4-methyl-1,3-phenylenebismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, and prepolymers of these maleimide compounds with amine compounds. These maleimide compounds (D) can be used individually or in combination of two or more.

[0022] The maleimide compound (D) may be a commercially available product or a preparation made by a known method. Examples of commercially available maleimide compounds (D) include "BMI-70," "BMI-80," and "BMI-1000P" from K.I. Chemicals Co., Ltd., "BMI-3000," "BMI-4000," "BMI-5100," "BMI-7000," and "BMI-2300" from Yamato Chemical Industries, Ltd., and "MIR-3000" from Nippon Kayaku Co., Ltd.

[0023] The proportion of maleimide compound (D) is preferably 30% by mass or more and 100% by mass or less relative to composition (X). In this case, a cured product with superior tracking resistance and high heat resistance can be obtained. This proportion is more preferably 70% by mass or less.

[0024] (Phenolic compound) As described above, the composition (X) contains a phenolic compound (B) as a resin component. The phenolic compound (B) 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; a polyfunctional phenolic resin such as a triphenolmethane type resin; a dicyclopentadiene type phenolic resin such as a dicyclopentadiene type phenol novolak resin or a dicyclopentadiene type naphthol novolak resin; a terpene-modified phenolic resin; a bisphenol type resin such as bisphenol A or bisphenol F; and at least one selected from the group consisting of a triazine-modified novolak resin.

[0025] The equivalent amount of the phenolic compound (B) with respect to 1 equivalent of the epoxy compound (A) is preferably in the range of 0.8 equivalents or more and 1.2 equivalents or less. In this case, the composition (X) has good curability and can achieve high heat resistance and high strength of the cured product.

[0026] (Filler) The filler (C) can reduce the linear expansion coefficient of the composition. In an embodiment, the filler (C) includes a silicone resin filler (c1).

[0027] The silicone resin filler (c1) includes a structural unit having a cyclic siloxane structure represented by the formula (1).

[0028] Si n O 2n R n ···(1) n is an integer of 3 or more and 5 or less. Each R is independently H, CH3, or CH2CH3. When R is a monovalent hydrocarbon having 3 or more carbon atoms, the fluidity of the composition (X) may be impaired. Among Rs in the formula (1), at least one is CH3 or CH2CH3.

[0029] Furthermore, it is preferable that the constituent units having a cyclic siloxane structure include at least one selected from the group consisting of the constituent units shown in formula (2), formula (3), and formula (4). In this case, it becomes easier to achieve excellent tracking resistance and a low modulus of elasticity in the cured product.

[0030] [ka]

[0031] The silicone resin filler (c1) may contain only one type of filler containing the same structural unit. The silicone resin filler (c1) may contain multiple types of fillers containing different structural units. In this case, the silicone resin filler (c1) contains at least one of the structural units shown in formula (2), formula (3), and formula (4), and contains two or more types of fillers containing different structural units.

[0032] The average particle size of the silicone resin filler (c1) is preferably 0.5 μm or more and 20 μm or less. If the average particle size is 0.5 μm or more, composition (X) can have good fluidity. If the average particle size is 20 μm or less, composition (X) can have good fluidity and achieve high strength and low elastic modulus of the cured product. The average particle size is more preferably 1.0 μm or more. The average particle size is more preferably 15 μm or less. Note that the average particle size refers to the particle size corresponding to 50% of the volume-based integrated value calculated from the measured particle size distribution by laser diffraction and scattering method. The average particle size can be measured by employing a wet method of laser particle size distribution system and dispersing with ultrasound.

[0033] The filler (C) preferably contains silica powder (c2) in addition to the silicone resin filler (c1). The silica powder (c2) can increase the strength of the cured product. The silica powder (c2) includes at least one selected from the group consisting of fused silica powder and crystalline silica powder.

[0034] Furthermore, if the filler (C) does not contain silicone resin filler (c1) but contains silica powder (c2), the elastic modulus of the cured product becomes excessively high. In contrast, if the filler (C) contains both silicone resin filler (c1) and silica powder (c2), high strength and a low elastic modulus of the cured product can be achieved.

[0035] The average particle size of the silica powder (c2) is preferably 10 μm or more and 20 μm or less. If the average particle size is 10 μm or more, composition (X) may have good fluidity. If the average particle size is 20 μm or less, composition (X) may have good fluidity and achieve high strength and low elastic modulus of the cured product. This average particle size is the particle size corresponding to 50% of the volume-based integrated value calculated from the particle size distribution measured by the laser diffraction-scattering method, and can be measured using a laser diffraction-scattering particle size distribution analyzer.

[0036] The filler (C) may include inorganic fillers other than silica powder (c2), as long as this does not impair the effects of the present disclosure. The inorganic filler includes, for example, at least one selected from the group consisting of titanium oxide powder, mica powder, alumina powder, aluminum nitride powder, titanium oxide powder, silicon nitride powder, and boron nitride powder.

[0037] The proportion of filler (C) is preferably 75% by mass or more and 88% by mass or less relative to composition (X). If this proportion is 75% by mass or more, a cured product with superior tracking resistance can be obtained. If this proportion is 88% by mass or less, composition (X) can have good fluidity. This proportion is more preferably 80% by mass or more. This proportion is even more preferably 85% by mass or less.

[0038] Furthermore, if composition (X) contains a maleimide compound (D), the content of filler (C) is preferably 300 parts by mass or more and 800 parts by mass or less, based on 100 parts by mass of the total of epoxy compound (A), maleimide compound (D), and phenol compound (B). If the content is 300 parts by mass or more, a cured product with even better tracking resistance can be obtained. If the content is 800 parts by mass or less, composition (X) can have better fluidity. It is more preferable that the content is 500 parts by mass or more. It is more preferable that the content is 600 parts by mass or less.

[0039] The proportion of silicone resin filler (c1) is preferably 1% by mass or more and 30% by mass or less relative to the filler (C). If this proportion is 1% by mass or more, a cured product with superior tracking resistance, higher heat resistance, and a lower elastic modulus can be obtained. If this proportion is 30% by mass or less, the composition (X) has good fluidity and high strength can be achieved in the cured product. This proportion is more preferably 3% by mass or more, and even more preferably 5% by mass or more. This proportion is more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0040] (Additives) Composition (X) may contain components other than epoxy compounds (A), phenol compounds (B), fillers (C), and maleimide compounds (D), to the extent that they do not impair the effects of the present disclosure. Components other than epoxy compounds (A), phenol compounds (B), fillers (C), and maleimide compounds (D) include, for example, additives. Additives include, for example, at least one selected from the group consisting of stress-reducing agents (E), silane coupling agents (F), curing accelerators (G), mold release agents, colorants, ion trapping agents, and flame retardants.

[0041] The stress-reducing material (E) can contribute to reducing the elasticity of the cured product. The stress-reducing material (E) includes, for example, resin particles other than silicone resin filler (c1). The resin particles include, for example, at least one selected from the group consisting of (meth)acrylic resin, silicone resin, and butadiene resin. Note that the silicone resin does not include silicone resin filler (c1).

[0042] The silane coupling agent (F) can contribute to improving the strength of the cured product. The silane coupling agent (F) includes at least one selected from the group consisting of glycidoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; aminosilanes such as N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; alkylsilanes; ureidosilanes; and vinylsilanes. The proportion of the silane coupling agent (F) is preferably 0.1% by mass or more and 1.0% by mass or less based on the total amount of the filler (C).

[0043] The curing accelerator (G) can improve the reactivity between epoxy compounds (A), etc., and phenolic compounds (B). Examples of curing accelerators (G) include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, and 2-ethyl-4-methylimidazole; cycloamidines such as 1,8-diazabicyclo[5.4.0]undecene-7, 1,5-diazabicyclo[4.3.0]nonene-5, and 5,6-dibutylamino-1,8-diazabicyclo[5.4.0]undecene-7; tertiary amines such as 2-(dimethylaminomethyl)phenol, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; tributylphosphine, methyldiphenylphosphine, and triphenyl The compound contains at least one selected from the group consisting of organic phosphines such as chlorophosphine, tris(4-methylphenyl)phosphine, diphenylphosphine, addition products of triphenylphosphine and parabenzoquinone, and phenylphosphine; tetra-substituted phosphonium and tetra-substituted borates such as tetraphenylphosphonium-tetraphenylborate, tetraphenylphosphonium-ethyltriphenylborate, and tetrabutylphosphonium-tetrabutylborate; quaternary phosphonium salts having counteranions other than borate; and tetraphenylboron salts such as 2-ethyl-4-methylimidazole-tetraphenylborate and N-methylmorpholine-tetraphenylborate. Furthermore, the content of the curing accelerator (G) is preferably 0.1% by mass or more and 5.0% by mass or less, and more preferably 0.5% by mass or more and 2.0% by mass or less, relative to the total of the epoxy compound (A), phenol compound (B), and maleimide compound (D).

[0044] The release agent includes, for example, at least one selected from the group consisting of natural waxes such as carnauba wax; synthetic waxes such as montanic acid ester wax and polyethylene oxide wax; higher fatty acids such as zinc stearate and their metal salts; paraffin; and carboxylic acid amides such as erucic acid amide.

[0045] 2.2 Manufacturing method The method for producing composition (X) will be described in detail.

[0046] Composition (X) can be prepared by mixing the components of the above composition (X). In this case, for example, the components are mixed until sufficiently homogeneous using a mixer, blender, etc., then kneaded while heating using a kneading machine such as a hot roll or kneader, and then cooled to room temperature.

[0047] A powdered composition (X) may be produced by grinding the composition (X) prepared by the above method. Alternatively, a tablet-shaped composition (X) may be produced by compressing the powdered composition (X) into tablets. In addition to these, the composition (X) may have any other suitable shape. The composition (X) according to the embodiment is preferably solid at 25°C.

[0048] 2.3 Characteristics The properties of composition (X) and its cured product will be described.

[0049] (Spiral flow length) It is preferable that composition (X) has moderately high fluidity at high temperatures. The fluidity of composition (X) can be confirmed by a spiral flow test. It is preferable that the flow distance (cm) when composition (X) is molded under the conditions of a mold temperature of 170°C, an injection pressure of 6.9 MPa, and a molding time of 120 seconds is 70 cm or more. If this flow distance is 70 cm or more, the ease of molding can be improved.

[0050] (Geltime) It is preferable that the curing time of composition (X) after heating, i.e., the curing rate, is adjusted to a specific range. The curing rate of composition (X) can be confirmed by measuring the gel time. If the curing torque of composition (X) is measured over time at 170°C and the time until the curing torque value reaches 0.1 kgf is 50 seconds or less, the curing rate of composition (X) can be well maintained. It is preferable that this time is 40 seconds or less.

[0051] (Glass transition temperature) A higher glass transition temperature is preferable for the cured product of composition (X). More specifically, the glass transition temperature of the cured product is preferable to be higher than the maximum operating temperature of the semiconductor device (junction temperature). For example, if the junction temperature is 200°C, the glass transition temperature of the cured product is preferably 200°C or higher. In this case, the heat resistance reliability of the semiconductor device equipped with a sealing portion containing the cured product can be improved. The method for measuring the glass transition temperature will be described in detail in the Examples section.

[0052] (Bending strength) The bending strength of the cured product of composition (X) is preferably moderately high. The bending strength of the cured product is preferably 100 MPa or higher. Adjusting the bending strength within the above range can improve the reliability of the semiconductor device. A bending strength of 120 MPa or higher is more preferable. The method for measuring the bending strength will be described in detail in the Examples section. Note that composition (X) is more likely to achieve the above bending strength values ​​if it contains silica powder (c2).

[0053] (Flexural modulus) The flexural modulus of the cured product of composition (X) is preferably moderately low. The flexural modulus of the cured product is preferably 16 GPa or less. If the flexural modulus is adjusted within the above range, peeling of the sealing portion that occurs when the semiconductor device is heated can be suppressed. A flexural modulus of 15 MPa or less is more preferable. The method for measuring the flexural modulus will be described in detail in the Examples section. Note that composition (X) can achieve the above flexural modulus value by containing a silicone resin filler (c1).

[0054] (Tracking resistance) The cured product of composition (X) may have high tracking resistance. The cured product will have a comparative tracking index (CTI) of 600V or higher, as measured according to the IEC 60112 method, and will be ranked as a Group I material, the highest rank, in the European standard EN61984. Semiconductor devices equipped with a seal containing the cured product will be extremely reliable. The method for measuring the comparative tracking index will be described in detail in the Examples section.

[0055] 3. Semiconductor equipment As described above, composition (X) according to the embodiment can be used to encapsulate semiconductor devices. The cured product of composition (X) has excellent tracking resistance and a low elastic modulus. Therefore, composition (X) can be applied as a composition for encapsulating semiconductor devices that have semiconductor elements that generate a large amount of heat. Specifically, examples of semiconductor devices that have semiconductor elements that generate a large amount of heat include power semiconductor devices, in which case the semiconductor element is a power semiconductor element.

[0056] The configuration of the semiconductor device 1 according to the embodiment will be described in detail. The semiconductor device 1 comprises a semiconductor element 50 and a sealing portion 62 that seals the semiconductor element 50. The sealing portion 62 contains a cured product of composition (X). The semiconductor device 1 may also include a conductor. The conductor is, for example, a lead frame 52. However, the conductor is not limited to a lead frame 52, and may be, for example, a conductor wiring on a printed circuit board. The conductor may have a nickel-containing plating layer. Examples of package forms for the semiconductor device 1 according to the embodiment include insert-type packages such as Mini, D-pack, D2-pack, To220, To3P, and dual in-line package (DIP), and surface-mount type packages such as quad flat package (QFP), small outline package (SOP), and small outline J-lead package (SOJ).

[0057] Figure 1 shows a schematic cross-sectional view of an example of a semiconductor device 11. The semiconductor device 11 comprises a conductive metal lead frame 52, a semiconductor element 50 mounted on the lead frame 52, wires 56 that electrically connect the semiconductor element 50 and the lead frame 52, and a sealing portion 62 that seals the semiconductor element 50.

[0058] In this embodiment, the lead frame 52 comprises a die pad 58, an inner lead 521, and an outer lead 522. The lead frame 52 is made of, for example, copper or an iron alloy such as 42 alloy. Preferably, the lead frame 52 is provided with a plating layer 54. In this case, corrosion of the lead frame 52 is suppressed. The plating layer 54 contains at least one metal from among silver, nickel, and palladium. The plating layer 54 may contain only one of the metals from among silver, nickel, and palladium, or it may contain an alloy containing at least one of the metals from among silver, nickel, and palladium. The plating layer 54 may have a laminated structure, specifically, for example, a laminated structure consisting of a palladium layer, a nickel layer, and a gold layer. The thickness of the plating layer 54 is, for example, 1 μm or more and 20 μm or less, but is not particularly limited thereto.

[0059] The semiconductor element 50 is fixed onto the die pad 58 of the lead frame 52 with an appropriate die bond material 60. This mounts the semiconductor element 50 onto the lead frame 52.

[0060] In this embodiment, the semiconductor element 50 is a power semiconductor element composed of silicon (Si), silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), or diamond. The semiconductor element 50 may also be, for example, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, a solid-state image sensor, etc.

[0061] Next, the semiconductor element 50 and the inner lead 521 in the lead frame 52 are connected with a wire 56. The wire 56 may be made of gold, but may also contain at least one of copper and silver. For example, the wire 56 may be made of silver or copper. If the wire 56 contains at least one of copper and silver, the wire 56 may be coated with a thin film of a metal such as palladium.

[0062] Next, the composition (X) is molded to form a sealing portion 62 that seals the semiconductor element 50. The sealing portion 62 also seals the wire 56. The sealing portion 62 also seals the die pad 58 and the inner lead 521, and therefore the sealing portion 62 is in contact with the lead frame 52, and if the lead frame 52 has a plating layer 54, it is in contact with the plating layer 54.

[0063] It is preferable to produce the sealing portion 62 by molding composition (X) by a pressure molding method. The pressure molding method is, for example, injection molding, transfer molding, or compression molding.

[0064] When forming composition (X) by pressure molding, the molding pressure is preferably 3.0 MPa or higher, and the molding temperature is preferably 120°C or higher. In this case, a semiconductor device 11 can be obtained in which the semiconductor element 50 is sealed in a uniform sealing portion 62 with few unfilled areas, so-called weld voids or internal voids. In particular, in the case of transfer molding, the injection pressure of composition (X) into the mold is preferably 3 MPa or higher, and more preferably 4 MPa or higher and 710 MPa or lower. The heating temperature (mold temperature) is preferably 120°C or higher, and more preferably 160°C or higher and 190°C or lower. The heating time is preferably 30 seconds or more and 300 seconds or lower, and more preferably 60 seconds or more and 180 seconds or lower.

[0065] In the transfer molding method, it is preferable to perform post-curing by heating the sealing portion 62 in the mold while the mold is closed, after which the semiconductor device 11 is removed by opening the mold. The heating conditions for post-curing are, for example, a heating temperature of 160°C to 190°C and a heating time of 2 hours to 8 hours.

[0066] In the case of compression molding, the compression pressure is preferably 3 MPa or higher, and more preferably 5.0 MPa to 10 MPa. The heating temperature (mold temperature) is preferably 120°C or higher, and more preferably 150°C to 185°C. The heating time is preferably 60 seconds to 300 seconds.

[0067] The structure of the semiconductor device 1 is not limited to that shown in Figure 1. The semiconductor device 1 only needs to include a semiconductor element 50 and a sealing portion 62 that seals the semiconductor element 50, and may be in the form shown in Figure 2 (see Figure 2).

[0068] The semiconductor device 12 shown in Figure 2 will now be described. Note that the explanation of the semiconductor device 12 shown in Figure 2 will omit details that are the same as those of the semiconductor device 11 shown in Figure 1.

[0069] For example, the semiconductor device 12 may include a DBC (Direct Bonding Copper) substrate 70, a semiconductor element 50 mounted on the DBC substrate 70, and a sealing portion 62 that seals the semiconductor element 50 on the DBC substrate 70 (see Figure 2). The use of a DBC substrate 70 has the advantage of making it easier to dissipate the heat generated in the semiconductor device 12. The configuration of the semiconductor device 12 shown in Figure 2 is suitable for power semiconductors.

[0070] The DBC substrate 70 is composed of two copper plates 71 and 73 and a ceramic substrate 72 interposed between the copper plates 71 and 73. The DBC substrate 70 of the semiconductor device 12 is stacked in the order of the first copper plate 71, the ceramic substrate 72, and the second copper plate 73, in order from closest to the semiconductor element 50. In other words, the semiconductor element 50 is located on the first copper plate 71.

[0071] For example, solder 57 is interposed between the semiconductor element 50 and the first copper plate 71.

[0072] The semiconductor device 12 may include a lead frame 52. The configuration of the lead frame 52 may be the same as that of the semiconductor device 11 shown in Figure 1. For example, the lead frame 52 is placed on the first copper plate 71.

[0073] The semiconductor device 12 may include wires 56. The configuration of wires 56 may be the same as that of the semiconductor device 11 shown in Figure 1. Wires 56 connect the semiconductor element 50 to the first copper plate.

[0074] Similar to the semiconductor device 11 shown in Figure 1, in the semiconductor device 12 shown in Figure 2, a sealing portion 62 that encapsulates the semiconductor element 50 is formed by molding the composition (X) (see Figure 2). In the semiconductor device 12 shown in Figure 2, the method and conditions for molding the composition (X) may be the same as those for the semiconductor device 11 shown in Figure 1.

[0075] Furthermore, the semiconductor element 12 comprising the DBC substrate 70 may also be provided with a heat dissipation structure. The heat dissipation structure includes a heat sink. The heat sink is positioned on the side of the DBC substrate 70 opposite to the side on which the semiconductor element 50 is located. The heat sink is made of a metal such as copper. The heat sink is not sealed by the sealing portion 62 and is exposed to the outside (not shown). Also, a thermal conductive sheet may be interposed between the DBC substrate 70 and the heat sink. In this case, the thermal conductive sheet may be in direct contact with the second copper plate 73, or solder may be interposed between the thermal conductive sheet and the second copper plate 73. In other words, the thermal conductive sheet may be soldered to the second copper plate 73 and joined to the second copper plate 73. The thermal conductive sheet is made of an appropriate thermal conductive material (thermal conductive interface material: TIM). The thermal conductive sheet may or may not be sealed by the sealing portion 62.

[0076] Thus, composition (X) can be used in semiconductor devices 1 of various forms.

[0077] 4. Appearance A composition (X) according to a first aspect of the present disclosure comprises an epoxy compound (A), a phenol compound (B), and a filler (C). The filler (C) comprises a silicone resin filler (c1). The silicone resin filler (c1) comprises a constituent unit having a cyclic siloxane structure represented by formula (1).

[0078] Si n O 2n R n ...(1) n is an integer between 3 and 5 (inclusive), and R is independently H, CH3, or CH2CH3.

[0079] A composition (X) according to a second aspect of the present disclosure further contains a maleimide compound (D) in the first aspect.

[0080] In a third aspect of the present disclosure, composition (X) comprises, in the first or second aspect, at least one constituent unit having a cyclic siloxane structure selected from the group consisting of the constituent unit represented by formula (2), the constituent unit represented by formula (3), and the constituent unit represented by formula (4).

[0081] [ka]

[0082] In the composition (X) according to the fourth aspect of the present disclosure, in any one of the first to third aspects, the proportion of silicone resin filler (c1) is 1% by mass or more and 30% by mass or less with respect to the filler (C).

[0083] In the composition (X) according to the fifth aspect of this disclosure, in any one of the first to fourth aspects, the average particle size of the silicone resin filler (c1) is 0.5 μm or more and 20 μm or less.

[0084] A composition (X) according to a sixth aspect of the present disclosure, in any one of the first to fifth aspects, comprises a filler (C) containing silica powder (c2).

[0085] In the sixth embodiment, the composition (X) according to the seventh aspect of this disclosure has an average particle size of silica powder (c2) of 10 μm or more and 20 μm or less.

[0086] In the eighth aspect of the present disclosure, the composition (X) is such that, in any one of the second to seventh aspects, the content of the filler (C) is 300 parts by mass or more and 800 parts by mass or less, based on 100 parts by mass of the total of the epoxy compound (A), the maleimide compound (D), and the phenol compound (B).

[0087] A composition (X) according to the ninth aspect of the present disclosure further contains a stress-reducing material (E) in any one of the first to eighth aspects.

[0088] A composition (X) according to the tenth aspect of the present disclosure further contains a silane coupling agent (F) in any one of the first to ninth aspects.

[0089] A composition (X) according to the eleventh aspect of the present disclosure further contains a curing accelerator (G) in any one of the first to tenth aspects.

[0090] A semiconductor device (1) according to a twelfth aspect of the present disclosure comprises a semiconductor element (50) and a sealing portion (62) that seals the semiconductor element (50). The sealing portion (62) includes a cured product of a composition (X) according to any one of the first to eleventh aspects.

[0091] In the 12th embodiment, the semiconductor device (1) according to the 13th aspect of this disclosure is a power semiconductor device in which the semiconductor element (50) is a power semiconductor element. [Examples]

[0092] The present disclosure will be explained in more detail below with reference to examples and comparative examples. However, this disclosure is not limited to the examples described below.

[0093] 1. Ingredients The components used to prepare the compositions of the examples and comparative examples are as follows:

[0094] (Epoxy compound) Epoxy compound #1: Biphenyl aralkyl type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., product name NC-3000.

[0095] (Phenol compounds) Phenolic compound #1: Naphthol cresol-type phenolic resin, manufactured by UBE Corporation, product name MEH-7000.

[0096] (filling material) Filler #1: Fused silica powder, manufactured by Denka Co., Ltd., product name FB910 Filler #2: Silicone resin filler containing the constituent units shown in formula (2) (average particle size 11 μm), manufactured by Momentive Performance Materials Japan LLC, product name TOSPEAL 1100.

[0097] Filler #3: Silicone resin filler containing the constituent units shown in formula (3) (average particle size 2 μm), manufactured by Momentive Performance Materials Japan LLC, product name TOSPEAL 120.

[0098] (Maleimide compounds) Maleimide compound #1: Bismaleimide resin, manufactured by Yamato Chemical Industries, Ltd., product name BMI-2300.

[0099] (Additives) Additive #1: Stress-reducing agent, manufactured by Dow-Toray Corporation, product name Z-6883. Additive #2: Silane coupling agent (N-phenyl-3-aminopropyltrimethoxysilane). Additive #3: Curing accelerator, manufactured by Shikoku Chemicals Co., Ltd., product name 2MZ-A. Additive #4: Release agent, natural carnauba wax. Additive #5: Coloring agent, carbon black.

[0100] 2. Method for preparing the composition Each component was uniformly melted and mixed in the proportions shown in the table using a hot double-roller machine, then cooled and pulverized to obtain the composition.

[0101] 3. Evaluation The obtained compositions were evaluated as described below. The results are shown in the table.

[0102] (Spiral flow length) Using a spiral flow measurement mold compliant with ASTM D3123, the composition was molded under the conditions of a mold temperature of 170°C, an injection pressure of 6.9 MPa, and a molding time of 120 seconds, and the flow distance (cm) was measured. Spiral flow is an indicator of moldability; a longer value indicates a material with better fluidity.

[0103] (Geltime) Torque was measured while heating the composition at 170°C using a Curlastometer VPS type manufactured by JSR Trading Co., Ltd. The time required from the start of heating until the measured torque reached 0.1 kgf·cm (9.81 mN·m) was investigated, and this time was defined as the gel time. From the perspective of rapid curing, a smaller value for this gel time is preferable.

[0104] (Glass transition temperature) The composition was transfer-molded at 180°C for 18 seconds under a molding pressure of 6.9 MPa, and then post-cured at 200°C for 4 hours to obtain a 5 × 5 × 15 mm test specimen. The dimensional change of the test specimen at a heating rate of 5°C / min was measured using a Rigaku TMA8310 thermomechanical analyzer, and the glass transition temperature was determined from the intersection of the tangent lines at 160-180°C and 300-320°C.

[0105] (Bending strength, bending modulus) In accordance with JIS K6911, test specimens were prepared from the composition, and the bending strength (MPa) and flexural modulus (GPa) were measured using a strength testing machine (INSTORON 68TM-5) (test specimen: 80 × 10 × 4 mm, support distance: 64 mm, test speed: 2 mm / min).

[0106] (Comparative tracking index) A molded product measuring φ50 mm × 3 mmt was prepared from the composition by transfer molding, and this molded product was then post-cured at 200°C for 4 hours. Subsequently, a sample was obtained by treating this molded product at 23°C and 50% RH for 40 hours.

[0107] Then, electrodes were brought into contact with the surface of the sample piece and a voltage was applied, and 0.1% ammonium chloride was dropped into the center between the electrodes at a rate of 30 ± 5 seconds per drop.

[0108] The procedure of dispensing 100 drops was considered one operation, and this operation was repeated five times. If the average number of drops at which tracking occurred during the five operations was 50 drops or more, the voltage was increased by 25V increments, and the same test was repeated until the voltage at which the average number of drops at which tracking occurred was less than 50 drops. The electrode distance was 4 mm ± 0.1 mm, and the test range was 300 to 600 V.

[0109] [Table 1] [Explanation of Symbols]

[0110] 1 Semiconductor device 50 Semiconductor elements 62 Sealing part

Claims

1. It contains an epoxy compound (A), a phenol compound (B), and a filler (C), The filler (C) includes a silicone resin filler (c1), The silicone resin filler (c1) includes a constituent unit having a cyclic siloxane structure represented by formula (1), Yes ｎ O ２ｎ R ｎ ・・・(1) n is an integer between 3 and 5, and R is independently H and CH. ３ or CH ２ CH ３ That is, Sealing resin composition.

2. Further containing maleimide compound (D), The encapsulating resin composition according to claim 1.

3. The aforementioned cyclic siloxane structure comprising at least one selected from the group consisting of the constituent units represented by formula (2), formula (3), and formula (4), 【Chemistry 1】 The encapsulating resin composition according to claim 1.

4. The proportion of the silicone resin filler (c1) is 1% by mass or more and 30% by mass or less relative to the filler (C). The encapsulating resin composition according to claim 1.

5. The average particle size of the silicone resin filler (c1) is 0.5 μm or more and 20 μm or less. The encapsulating resin composition according to claim 1.

6. The filler (C) contains silica powder (c2), The encapsulating resin composition according to claim 1.

7. The average particle size of the silica powder (c2) is 10 μm or more and 20 μm or less. The encapsulating resin composition according to claim 6.

8. The content of the filler (C) is 300 parts by mass or more and 800 parts by mass or less, based on 100 parts by mass of the total of the epoxy compound (A), the maleimide compound (D), and the phenol compound (B). The encapsulating resin composition according to claim 2.

9. Further containing stress-reducing material (E), The encapsulating resin composition according to claim 1.

10. It further contains a silane coupling agent (F), The encapsulating resin composition according to claim 1.

11. Further containing a hardening accelerator (G), The encapsulating resin composition according to claim 1.

12. The device comprises a semiconductor element and a sealing portion that seals the semiconductor element. The sealing portion includes a cured product of the sealing resin composition according to any one of claims 1 to 11. Semiconductor equipment.

13. A semiconductor device is a power semiconductor device. The semiconductor device according to claim 12.

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