Sealing resin composition, semiconductor device, and method for manufacturing the sealing resin composition

Abstract

The present invention provides a encapsulation resin composition containing fluid, plant-derived silica. [Solution] In the semiconductor device 100, the sealing resin composition for forming the heat dissipation layer 20 that adheres to the circuit layer 30 and the substrate 10, and the sealing layer 40 that seals the circuit layer 30 and the semiconductor element 50, comprises a thermosetting resin and an inorganic filler, wherein the inorganic filler contains silica particles derived from plants, and the silica particles derived from rice husks have a sphericity of 0.75 or higher as measured by flow-type image analysis in the particle size class of 1 μm to 30 μm.

Description

Technical Field

[0001] The present invention relates to a sealing resin composition, a semiconductor device, and a method for producing a sealing resin composition.

Background Art

[0002] A sealing resin composition used for a semiconductor device is required to have a low thermal expansion coefficient, high thermal conductivity (heat dissipation property), insulation property, and chemical stability. Currently, mineral silica made from silica stone and quartz is used for the majority of its components.

[0003] While mineral silica is used for the purpose of improving the performance of the sealing resin composition, it requires a large amount of electric power in the manufacturing process. Therefore, due to concerns about the impact on the global environment, it has been considered to use plant-derived silica instead of conventional mineral silica.

[0004] Patent Document 1 describes that in an oxygen-free atmosphere, rice husk is carbonized by a carbonization device that stirs while carbonizing at a temperature range of 500°C to 700°C to produce rice husk charcoal, and the rice husk charcoal is put into ion-exchanged water and stirred at a temperature range of 30°C to 100°C of the ion-exchanged water to dissolve and extract amorphous silica in the ion-exchanged water.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] From the perspective of the impact on the global environment, it is preferable to use a sealing resin composition containing plant-derived silica. However, the fluidity and curability of a sealing resin composition containing plant-derived silica may decrease.

[0007] One example of a problem that the present invention aims to solve is to provide a encapsulating resin composition containing plant-derived silica with good fluidity and curability. [Means for solving the problem]

[0008] According to the present invention, the following encapsulating resin composition, semiconductor device, and method for producing the encapsulating resin composition are provided. [1] It comprises a thermosetting resin and an inorganic filler. The inorganic filler contains plant-derived silica particles, The aforementioned plant-derived silica particles are a sealing resin composition having a sphericity of 0.75 or higher, as measured by flow-type image analysis, in the particle size class of 1 μm to 30 μm. [2] The gel time, measured in accordance with JIS C 2161, is between 15 seconds and 120 seconds. [1] The sealing resin composition described above. [3] The spiral flow measured under the following conditions is 50 cm or more: The sealing resin composition described in [1] or [2]. [conditions] Using a low-pressure transfer molding machine, resin molding material is injected into a mold for spiral flow measurement in accordance with EMMI-1-66 under conditions of mold temperature 175°C, injection pressure 6.9 MPa, and holding pressure time 180 seconds, and the measured flow length is defined as the spiral flow. [4] The aforementioned plant-derived silica particles are measured under the following conditions: the Na ion content is 100 ppm or less, and the SO4 ion content is 100 ppm or less. A sealing resin composition according to any one of [1] to [3]. [conditions] 5 g of the plant-derived silica particles are kneaded in 50 ml of 125°C hot water for 20 minutes, and the content of Na ions and SO4 ions in the hot water after kneading is measured by ion chromatography. [5] The particles of the plant-derived silica have an average particle diameter D50, measured by the laser diffraction scattering method, of 1 μm or more and 30 μm or less. The encapsulating resin composition according to any one of [1] to [4]. [6] The thermosetting resin contains an epoxy resin. The encapsulating resin composition according to any one of [1] to [5]. [7] The plant-derived silica is silica derived from rice husks. The encapsulating resin composition according to any one of [1] to [6]. [8] A semiconductor element, It is composed of a cured product of the encapsulating resin composition according to any one of [1] to [7], A semiconductor device in which the semiconductor element is encapsulated by a cured product of the encapsulating resin composition. [9] A combustion step of burning a plant and recovering ash, An elution step of eluting the silica contained in the ash into a solution, An extraction step of extracting and removing the eluted silica, An addition step of adding the extracted silica as at least part of an inorganic filler to a thermosetting resin A method for producing an encapsulating resin composition, comprising:

[10] After the extraction step, further comprising a washing step of washing the extracted silica, The method for producing an encapsulating resin composition according to [9]. [Effects of the Invention]

[0009] According to the present invention, an encapsulating resin composition containing plant-derived silica with good fluidity and curability can be provided. [Brief Description of the Drawings]

[0010] [Figure 1] It is a figure which shows sectional drawing of an example of the semiconductor device which concerns on this embodiment.

Best Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. Also, the drawings are schematic and do not match the actual dimensional ratios.

[0012] [Semiconductor device 100] FIG. 1 shows a cross-sectional view of an example of the semiconductor device 100 according to the present embodiment. The semiconductor device 100 includes a substrate 10, a heat dissipation layer 20, a circuit layer 30, a sealing layer 40, and a semiconductor element 50. As shown in FIG. 1, the heat dissipation layer 20 is disposed on one surface of the substrate 10. And, a circuit layer 30 for mounting a semiconductor element is disposed on one surface of the heat dissipation layer 20 opposite to the substrate 10. And, the heat dissipation layer 20, the circuit layer 30, and the semiconductor element 50 are sealed by the sealing layer 40.

[0013] [Substrate 10] The substrate 10 holds the heat dissipation layer 20. Although omitted in FIG. 1, heat dissipation members such as heat dissipation fins and radiators may be attached to the surface of the substrate 10 opposite to the heat dissipation layer 20. Thereby, the heat dissipation performance of the substrate is improved. Note that the heat dissipation member may be integrated with the substrate 10.

[0014] As the material constituting the substrate 10, for example, one or a combination of two or more selected from copper, copper alloy, aluminum, and aluminum alloy can be used. Among these, from the viewpoint of strength, it is preferable to include at least one of copper or aluminum.

[0015] [Heat dissipation layer 20] The heat dissipation layer 20 adheres to the circuit layer 30 and the substrate 10 and transmits the heat of the circuit layer 30 to the substrate 10. From the viewpoint of efficiently transmitting heat, the heat dissipation layer 20 preferably has a thermal conductivity of 3 W / (m·K) or more, more preferably 7 W / (m·K) or more, and even more preferably 12 W / (m·K) or more.

[0016] The material constituting the heat dissipation layer 20 is, for example, a thermosetting resin. As the thermosetting resin, one or more types selected from epoxy resin, phenolic resin, urea resin, melamine resin, polyester (unsaturated polyester) resin, polyimide resin, silicone resin, and polyurethane resin can be used.

[0017] It is preferable to mix an inorganic filler composed of electrically insulating and highly thermally conductive particles into the heat dissipation layer 20. As the constituent materials of such inorganic filler particles, one or more types selected from metal oxides such as alumina and nitrides such as boron nitride can be used.

[0018] <Circuit layer 30> The circuit layer 30 is made of a conductive metallic material and, for example, a semiconductor element is mounted on it. The metallic material constituting the circuit layer 30 can be one or more selected from copper, copper alloys, aluminum, and aluminum alloys. At least a portion of the circuit layer 30 may be covered with a resist material such as a rust inhibitor.

[0019] <Sealing layer 40> The sealing layer 40 seals the heat dissipation layer 20, the circuit layer 30, and the semiconductor element 50. This suppresses deterioration such as corrosion of the circuit layer 30 and the semiconductor element 50. The sealing layer 40 is formed, for example, using the sealing resin composition according to this embodiment, which will be described later.

[0020] [Manufacturing method for semiconductor devices] As an example, the method for manufacturing a semiconductor device according to this embodiment includes: a first step of placing a heat dissipation material on a substrate 10; a second step of placing a circuit layer 30 on one side of the heat dissipation material opposite to the substrate 10; a third step of curing the heat dissipation material by heating to form a heat dissipation layer 20; a fourth step of mounting a semiconductor element 50 on the side of the circuit layer 30 opposite to the heat dissipation layer 20; and a fifth step of forming a sealing layer 40 that seals the heat dissipation layer 20, the circuit layer 30, and the semiconductor element 50 by processing the sealing resin composition according to this embodiment by a transfer molding method or a compression molding method.

[0021] [Sealing resin composition] Next, the composition of the sealing resin composition according to this embodiment will be described in detail. The sealing resin composition according to this embodiment comprises a thermosetting resin and an inorganic filler, the inorganic filler comprising particles of plant-derived silica.

[0022] <Thermosetting resin> As the thermosetting resin, one or more types of cyanate ester resins can be used, selected from epoxy resins, phenolic resins, urea resins, melamine resins and other resins having a triazine ring, unsaturated polyester resins, maleimide resins such as bismaleimide compounds, polyurethane resins, diallyl phthalate resins, silicone resins, benzoxazine resins, polyimide resins, polyamideimide resins, benzocyclobutene resins, novolac-type cyanate resins, bisphenol A-type cyanate resins, bisphenol E-type phenolic resins, tetramethylbisphenol F-type cyanate resins, and other cyanate resins. Epoxy resins are particularly preferred as the thermosetting resin.

[0023] Epoxy resins include, specifically, bisphenol type epoxy resins such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetramethylbisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, and bisphenol Z type epoxy resin; novolac type epoxy resins such as phenol novolac type epoxy resin and cresol novolac type epoxy resin; biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, and phenol aralkyl type epoxy resin. One or more epoxy monomers selected from xyresins, arylalkylene epoxy resins, naphthalene epoxy resins, anthracene epoxy resins, phenoxy epoxy resins, dicyclobentadiene epoxy resins, norbornene epoxy resins, adamantane epoxy resins, fluorene epoxy resins, trisphenylmethane epoxy resins, 4-tert-butylphenyl glycidyl ether, m,p-cresyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, etc., can be used.

[0024] When the total encapsulating resin composition is 100 parts by mass, the lower limit of the thermosetting resin content is preferably 3 parts by mass or more, and more preferably 5 parts by mass or more. The upper limit of the thermosetting resin content is preferably 15 parts by mass or less, and more preferably 10 parts by mass or less. By keeping the thermosetting resin content within the above range, the curability and other properties of the encapsulating resin composition are improved.

[0025] <Inorganic filler> The inorganic filler contains particles of plant-derived silica. The plant-derived silica mentioned above is, for example, silica derived from rice husks. In addition to plant-derived silica particles, the inorganic filler may further contain particles composed of mineral-derived silica such as fused silica, crystalline silica, amorphous silicon dioxide, alumina, talc, titanium oxide, silicon nitride, aluminum nitride, etc.

[0026] When the total inorganic filler is 100 parts by mass, the lower limit of the content of plant-derived silica particles in the particle size class of 1 μm to 30 μm is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 20 parts by mass or more. Furthermore, the upper limit of the content of plant-derived silica particles in the particle size class of 1 μm to 30 μm is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, even more preferably 80 parts by mass or less, even more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less.

[0027] Furthermore, from the viewpoint of thermal conductivity, the particle size D50 of plant-derived silica particles is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more, as measured by laser diffraction scattering. In addition, the particle size D50 of plant-derived silica particles is preferably 30 μm or less, more preferably 25 μm or less, even more preferably 20 μm or less, even more preferably 10 μm or less, even more preferably 5 μm or less, and even more preferably 4 μm or less. The particle size D50 is measured, for example, using a laser diffraction particle size distribution analyzer.

[0028] Furthermore, from the viewpoint of thermal conductivity, the particle size D50 of the inorganic filler as a whole, as measured by laser diffraction scattering, is preferably 11 μm or more, more preferably 13 μm or more, and even more preferably 15 μm or more. Furthermore, the particle size D50 of the inorganic filler as a whole is preferably 25 μm or less, more preferably 22 μm or less, and even more preferably 20 μm or less. The particle size D50 is measured, for example, using a laser diffraction particle size distribution analyzer.

[0029] Furthermore, from the viewpoint of fluidity, the sphericity of plant-derived silica particles, as measured by flow-type image analysis, is preferably 0.75 or higher for particle size classes of 1 μm to 30 μm, more preferably 0.90 or higher, and even more preferably 1.0 or higher. Moreover, for particle size classes exceeding 5 μm and 20 μm or less, the sphericity is preferably 0.75 or higher, more preferably 0.90 or higher, and even more preferably 1.0 or higher. Measurement by flow-type image analysis is performed, for example, using a flow-type particle image analyzer.

[0030] Furthermore, from the viewpoint of fluidity, the sphericity of the inorganic filler as a whole, measured using a flow-type particle image analyzer, for particle size classes of 45 μm or larger, is preferably 0.75 or higher, more preferably 0.90 or higher, and even more preferably 1.0 or higher.

[0031] Furthermore, the plant-derived silica particles, as measured under the following conditions, preferably have a Na ion content of 100 ppm or less, more preferably 30 ppm or less, more preferably 25 ppm or less, and even more preferably 20 ppm or less. Also, the SO4 ion content is preferably 100 ppm or less, more preferably 40 ppm or less, more preferably 35 ppm or less, even more preferably 30 ppm or less, even more preferably 25 ppm or less, and even more preferably 20 ppm or less. [conditions] 5g of plant-derived silica particles are kneaded in 50ml of 125°C hot water for 20 minutes, and the sodium ion and SO4 ion content in the hot water after kneading is measured by ion chromatography.

[0032] When the total amount of the sealing resin composition is 100 parts by mass, the lower limit of the content of plant-derived silica particles is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, and even more preferably 25 parts by mass or more. The upper limit of the content of plant-derived silica particles is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, even more preferably 60 parts by mass or less, even more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less.

[0033] When the total amount of the sealing resin composition is 100 parts by mass, the lower limit of the inorganic filler content is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and even more preferably 70 parts by mass or more. Furthermore, the upper limit of the inorganic filler content is preferably 98 parts by mass or less, more preferably 95 parts by mass or less, and even more preferably 92 parts by mass or less.

[0034] <Hardening agent> The encapsulating resin composition according to this embodiment may further contain a curing agent. As the curing agent, for example, a phenolic resin curing agent can be used. Specifically, as the phenolic resin curing agent, one or more types selected from the following can be used: novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, bisphenol A type novolac resin, and triazine skeleton-containing phenol novolac resin; bisphenol compounds such as bisphenol A and bisphenol F (dihydroxydiphenylmethane); unmodified resol phenolic resin; resol-type phenolic resins such as oil-modified resol phenolic resins modified with tung oil, linseed oil, walnut oil, etc.; aralkyl-type phenolic resins such as phenol aralkyl resin and biphenyl aralkyl type phenolic resin; triphenylmethane type phenolic resin, etc.

[0035] When the total encapsulating resin composition is 100 parts by mass, the lower limit of the curing agent content is preferably 0.5 parts by mass or more, more preferably 0.7 parts by mass or more, and even more preferably 1.0 part by mass or more. The upper limit of the curing agent content is preferably 5.0 parts by mass or less, and more preferably 3.0 parts by mass or less. By keeping the curing agent content within the above ranges, the curability of the encapsulating resin composition is improved.

[0036] <Curing accelerator> The encapsulating resin composition according to this embodiment may further contain a curing accelerator to promote the reaction between the reactive groups of the thermosetting resin and the reactive groups of the curing agent. As the curing accelerator, one or more combinations of imidazole-based curing accelerators can be used; phosphorus atom-containing compounds such as organophosphines, tetrasubstituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds; amidines and tertiary amines such as dicyandiamide, 1,8-diazabicyclo[5.4.0]undecene-7, and benzyldimethylamine; nitrogen atom-containing compounds such as quaternary ammonium salts of the above amidines or tertiary amines, and polyhydroxynaphthalene compounds such as 2,3-dihydroxynaphthalene.

[0037] When the total encapsulating resin composition is 100 parts by mass, the lower limit of the curing accelerator content is preferably 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more. The upper limit of the curing accelerator content is preferably 1.0 part by mass or less, and more preferably 0.5 parts by mass or less. By keeping the curing accelerator content within the above ranges, the curability of the encapsulating resin composition is improved.

[0038] <Coupling agent> The encapsulating resin composition according to this embodiment may further contain a coupling agent. This can improve the fluidity of the encapsulating resin composition. Examples of coupling agents that can be used include silane-based coupling agents, titanium-based coupling agents, zirconia-based coupling agents, aluminum-based coupling agents, and the like.

[0039] When the total encapsulating resin composition is 100 parts by mass, the lower limit of the coupling agent content is preferably 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more. The upper limit of the coupling agent content is preferably 1.0 part by mass or less, and more preferably 0.5 parts by mass or less. By keeping the coupling agent content within the above range, the curability and other properties of the encapsulating resin composition are improved.

[0040] <Release agent> The sealing resin composition according to this embodiment may further contain a release agent. As the release agent, one or more types selected from natural waxes, synthetic waxes such as montanic acid esters and polyethylene oxide, higher fatty acids or their metal salts, paraffin, polyethylene oxide, carboxylic acid amides such as erucic acid amide, etc., can be used.

[0041] When the total amount of the sealing resin composition is 100 parts by mass, the lower limit of the release agent content is preferably 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more. Furthermore, the upper limit of the release agent content is preferably 1.0 part by mass or less, and more preferably 0.5 parts by mass or less.

[0042] <Low stress agent> The sealing resin composition according to this embodiment may contain a low-stress agent. As the low-stress agent, one or more combinations of the following can be used: silicone compounds such as silicone oil and silicone rubber; polybutadiene compounds; acrylonitrile-butadiene copolymers such as acrylonitrile-carboxyl-terminated butadiene copolymers.

[0043] When the total encapsulating resin composition is 100 parts by mass, the lower limit of the low-stress agent content is preferably 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more. Furthermore, the upper limit of the low-stress agent content is preferably 1.0 part by mass or less, and more preferably 0.5 parts by mass or less. By keeping the low-stress agent content below the above upper limit, the curing shrinkage rate of the encapsulating resin composition is reduced, and the adhesiveness is improved.

[0044] <Ion scavenger> The encapsulating resin composition according to this embodiment may contain an ion scavenger. As the ion scavenger, one or more selected from hydrotalcite, zeolite (aluminosilicate mineral), bismuth hydroxide, bismuth nitrate hydroxide, etc., can be used.

[0045] When the total encapsulating resin composition is 100 parts by mass, the lower limit of the ion-scavenging agent content is preferably 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more. Furthermore, the upper limit of the ion-scavenging agent content is preferably 1.0 part by mass or less, and more preferably 0.5 parts by mass or less.

[0046] <Coloring agent> The sealing resin composition according to this embodiment may contain a coloring agent. For example, carbon black can be used as the coloring agent.

[0047] When the total encapsulating resin composition is 100 parts by mass, the lower limit of the colorant content is preferably 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more. The upper limit of the colorant content is preferably 1.0 part by mass or less, and more preferably 0.5 parts by mass or less. By keeping the colorant content below the above upper limit, the curing shrinkage rate of the encapsulating resin composition is reduced, and the adhesiveness is improved.

[0048] <Additives> The sealing resin composition according to this embodiment may also contain other additives such as triazine compounds or reaction products of organopolysiloxanes having carboxyl groups and epoxy resins.

[0049] [Physical properties of the sealing resin composition] <Spiral Flow> Next, the physical properties of the encapsulating resin composition according to this embodiment will be described. First, the encapsulating resin composition preferably has a flow length of 50 cm or more, more preferably 80 cm or more, even more preferably 100 cm or more, even more preferably 130 cm or more, even more preferably 140 cm or more, even more preferably 160 cm or more, even more preferably 170 cm or more, and even more preferably 180 cm or more, as measured by a spiral flow test at a temperature of 175°C. By having the spiral flow within the above range, the encapsulating resin composition can obtain sufficient fluidity.

[0050] Furthermore, the spiral flow test described above can be performed, for example, by using a low-pressure transfer molding machine (KTS-15 manufactured by Kotaki Seiki Co., Ltd.) to inject the sealing resin composition into a mold for spiral flow measurement in accordance with EMMI-1-66 under conditions of mold temperature of 175°C, injection pressure of 6.9 MPa, and holding pressure time of 180 seconds, and then measuring the flow length.

[0051] <Geltime> The encapsulating resin composition according to this embodiment preferably has a gel time of 15 seconds or more, more preferably 30 seconds or more, even more preferably 40 seconds or more, and even more preferably 50 seconds or more. Furthermore, from the viewpoint of the handlingability of the encapsulating resin composition, the gel time is preferably 120 seconds or less, more preferably 100 seconds or less, even more preferably 90 seconds or less, and even more preferably 80 seconds or less. Having a gel time within the above range improves the processability of the encapsulating resin composition.

[0052] The gel time is measured in accordance with JIS C 2161 and is the time from when the sealing resin composition melts due to heat until it hardens, when the sealing resin composition is placed on a hot plate controlled at 175°C and kneaded with a spatula in strokes of approximately 1 per second.

[0053] <Glass transition temperature (Tg)> It is preferable that the glass transition temperature (Tg) of the test specimen obtained by molding the sealing resin composition by a transfer molding method is 120°C or higher.

[0054] <Coefficient of linear expansion> The coefficient of linear thermal expansion CTE1 at temperatures below the glass transition temperature (Tg) is 8 × 10⁻⁶. -6 It is preferable that the temperature is above / ℃. Furthermore, the coefficient of linear expansion CTE2 at temperatures above the glass transition temperature (Tg) is 30 × 10 -6 It is preferable that the temperature is above / ℃.

[0055] [Method for producing plant-derived silica] The plant-derived silica according to this embodiment can be produced by a manufacturing method that includes, for example, a combustion step of burning a plant (e.g., rice husks) and recovering the ash, an elution step of eluting the silica contained in the ash into a solution, and an extraction step of extracting and removing the eluted silica.

[0056] Furthermore, the method for producing plant-derived silica may further include a washing step for washing the extracted silica. Including a washing step allows for the removal of impurities such as ionic impurities contained in the silica. The washing step may be a step of washing the ash after the combustion step, a step of washing the silica extracted after the extraction step, or a step that includes both. Washing is carried out, for example, using water.

[0057] [Method for producing encapsulating resin composition] The sealing resin composition according to this embodiment is manufactured by a manufacturing method that includes a combustion step of burning plants (e.g., rice husks) and recovering the ash, an elution step of eluting silica contained in the ash into a solution, an extraction step of extracting and removing the eluted silica, and an addition step of adding the removed silica to a thermosetting resin as at least a part of the inorganic filler. The addition step can be obtained, for example, by adding plant-derived silica particles to each of the above-mentioned components as at least a part of the inorganic filler, mixing them, further melt-kneading them in a kneader such as a roll, kneader, or extruder, cooling, and then grinding. The washing step described above may be included before the addition step.

[0058] As described above, according to this embodiment, the plant-derived silica particles in the encapsulating resin composition have a sphericity of 0.75 or higher, as measured by flow-type image analysis, in the particle size class of 1 μm to 30 μm. Therefore, the encapsulating resin composition according to this embodiment has good fluidity and curability, even though it contains plant-derived silica. [Examples]

[0059] The present invention will be described in detail based on examples and comparative examples. However, the present invention is not limited to the examples.

[0060] The details of the raw materials used in each example and comparative example are described below. The plant-derived filler is silica particles derived from rice husks. The reaction product in the additive includes a molten reaction product obtained by heating and melting 66.1 parts by mass of bisphenol A type epoxy resin (manufactured by Javan Epoxy Resin, jER® YL6810, softening point 45°C, epoxy equivalent 172) at 140°C, adding 33.1 parts by mass of organopolysiloxane and 0.8 parts by mass of triphenylphosphine, and melting and mixing for 30 minutes. The sphericity of the plant-derived filler is the sphericity in the particle size class of 1 μm to 30 μm, measured by flow image analysis. • Thermosetting resin: Biphenylene skeleton-containing phenol aralkyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., NC3000L) • Hardener: Biphenylene skeleton-containing phenol aralkyl resin • Curing accelerators: Contains 4-hydroxy-2-(triphenylphosphonium)phenolate and 2,3-dihydroxynaphthalene. • Coupling agent: Phenylaminopropyltrimethoxysilane • Release agent: Contains erucic acid amide, oxidized polyethylene wax, and carnauba wax. • Low-stress agent: Carboxylate-terminated butadiene / acrylonitrile copolymer (manufactured by Ube Industries, Ltd., CTBN1008SP) • Additives: Contains a triazine compound (manufactured by Shikoku Chemicals, Inc., VD-HT) and a reaction product of an organopolysiloxane having a carboxyl group and an epoxy resin. • Coloring agent: Carbon black • Main filler: Spherical silica, D50: 40 μm, sphericity 0.84 or higher Subfiller 1: Spherical silica, D50: 5.2 μm, sphericity 0.95 or higher Subfiller 2: Crushed silica, D50: 4.7 μm (manufactured by Fumitec, FMT-05) • Fine powder filler: Spherical silica, D50: 0.5 μm ~ 1.5 μm • Plant-derived filler: Silica derived from rice husks, D50: 4.0 μm, sphericity 0.95 (manufactured by Chugai Ro Kogyo Co., Ltd.)

[0061] Furthermore, Table 1 lists the content of each ion in the plant-derived filler, as measured under the following conditions. [conditions] 5g of silica particles derived from rice husks are kneaded in 50ml of 125°C hot water for 20 minutes, and the content of each ion in the hot water after kneading is measured by ion chromatography.

[0062] [Table 1]

[0063] [Manufacturing of encapsulating resin compositions] Table 2 shows the parts by mass of each component per 100 parts by mass of the sealing resin composition in each example and comparative example. The sealing resin compositions of each example and comparative example were obtained by preparing and mixing each component listed in Table 2 in the ratios indicated, then melt-kneading them in a twin-screw roll extruder, cooling, and pulverizing them.

[0064] [Table 2]

[0065] The following measurements were performed on the encapsulating resin compositions of each example and comparative example. The measurement results are shown in Table 2. Note that the percentage of plant-derived filler in Table 2 is the value when the total mass of the filler is taken as 100 mass percent.

[0066] <Spiral Flow> Using a low-pressure transfer molding machine (KTS-15, manufactured by Kotaki Seiki Co., Ltd.), the sealing resin compositions of each example and comparative example were injected into a spiral flow measurement mold conforming to EMMI-1-66 under the following conditions: mold temperature: 175°C, measurement time: 5 minutes, injection pressure: 6.9 MPa, and holding pressure time: 180 seconds. The flow length was measured and defined as the spiral flow.

[0067] <Geltime> In accordance with JIS C 2161, the sealing resin compositions of each example and comparative example were placed on a hot plate controlled at 175°C and kneaded with a spatula in approximately one stroke per second. The time from when the sealing resin composition melted due to heat until it hardened was measured and defined as the gel time.

[0068] <Rectangular channel pressure> First, the encapsulating resin compositions of each example and comparative example were preheated and softened by heating them in a plunger (plunger size φ18mm) at 175°C for 3 seconds. Next, using a low-pressure transfer molding machine (NEC Corporation, 40t manual press), the softened encapsulating resin compositions obtained above were injected into a rectangular channel with a width of 13mm, a thickness of 0.5mm, and a length of 175mm, under the conditions of a mold temperature of 175°C and an injection speed of 24.7mm / sec. At this time, the change in pressure over time was measured using a pressure sensor embedded 25mm from the upstream end of the channel, and the minimum pressure (kgf / cm²) during the flow of the encapsulating resin composition was determined. 2 The pressure was measured and defined as the rectangular channel pressure. The rectangular channel pressure is a parameter of melt viscosity, and a smaller value indicates lower melt viscosity.

[0069] <Glass transition temperature (Tg) and coefficient of linear expansion> Tablets were obtained by compressing the encapsulating resin compositions of each example and comparative example. The obtained tablets were injected using a transfer molding machine under the conditions of a mold temperature of 175°C, injection pressure of 8.3 MPa, and curing time of 2 minutes to obtain molded products measuring 4 mm × 10 mm × 0.15 mm. These molded products were post-cured at 175°C for 4 hours to obtain test specimens. Next, using a thermomechanical analyzer (TMA / SS6100, Seiko Instruments), the expansion of the test specimen with respect to temperature was detected as an electrical output using a differential transformer while the temperature of the test specimen was increased from -65°C at a heating rate of 5°C / min while being pulled with a constant load (10 mN), and a graph showing the expansion of the test specimen with respect to temperature was created. The glass transition temperature (Tg) was then determined from the inflection point of the above graph, and the linear expansion coefficient CTE1 at temperatures below the calculated glass transition temperature (Tg) and the linear expansion coefficient CTE2 at temperatures above the glass transition temperature (Tg) were determined.

[0070] <Bending strength and bending modulus> The sealing resin compositions of each example and comparative example were injected into a mold using a transfer molding machine under the following conditions: mold temperature 175°C, injection pressure 9.8 MPa, and curing time 2 minutes. This yielded molded products measuring 10 mm × 80 mm × 4 mm. These molded products were then post-cured at 175°C for 4 hours to obtain test specimens. The bending strength (N / mm²) at room temperature (25°C) was then measured using these test specimens. 2 ) and flexural modulus (N / mm²) 2 The values ​​were measured in accordance with JIS K 6911.

[0071] <Ion concentration> The sealing resin compositions of each example and comparative example were cured at a temperature of 120°C for 2 hours to obtain cured products. The obtained cured products were ground in a grinding mill for 3 minutes to prepare a powder as a sample. 5 g of the obtained sample and 50 ml of pure water were placed in a Teflon® pressure-resistant container, sealed, and subjected to treatment (hot water extraction) at a temperature of 125°C and a relative humidity of 100% RH for 24 hours. Next, after cooling to room temperature, the extracted water was centrifuged and filtered through a 20 μm filter, and the filtrate was used as the extracted water. The obtained extracted water was analyzed by ion chromatography using an ion chromatograph (Thermo Fisher Scientific), and the ion concentration in the extracted water was measured. The obtained ion concentration was taken as the ion concentration in the cured product.

[0072] In this embodiment, up to 25 parts by mass of the total encapsulating resin composition by mass was able to be derived from plants. Furthermore, the encapsulating resin composition according to this embodiment performed at a similar level to the comparative example encapsulating resin composition that did not contain plant-derived silica in all of the above measurement items. In particular, there was no significant difference in the spiral flow value, which is an indicator of fluidity. [Explanation of Symbols]

[0073] 100 Semiconductor Equipment 10 circuit boards 20 Heat dissipation layer 30 circuit layers 40 sealing layer 50 Semiconductor elements

Claims

1. It comprises a thermosetting resin and an inorganic filler. The inorganic filler contains plant-derived silica particles, The aforementioned plant-derived silica particles are in a particle size class of 1 μm to 30 μm, and the sphericity measured by flow-type image analysis is 0.75 or higher in the sealing resin composition.

2. The gel time, measured in accordance with JIS C 2161, is between 15 seconds and 120 seconds. The encapsulating resin composition according to claim 1.

3. The spiral flow measured under the following conditions is 50 cm or more: The sealing resin composition according to claim 1 or 2. [conditions] Using a low-pressure transfer molding machine, the sealing resin composition is injected into a mold for spiral flow measurement in accordance with EMMI-1-66 under conditions of mold temperature of 175°C, injection pressure of 6.9 MPa, and holding pressure time of 180 seconds, and the measured flow length is defined as the spiral flow.

4. The aforementioned plant-derived silica particles are measured under the following conditions, and have a Na ion content of 100 ppm or less, and SO ４ The ion content is 100 ppm or less. The sealing resin composition according to claim 1 or 2. [conditions] 5 g of the plant-derived silica particles were kneaded in 50 ml of 125°C hot water for 20 minutes, and the amount of Na ions and SO2 contained in the hot water after kneading was measured. ４ The ion content is measured by ion chromatography.

5. The aforementioned plant-derived silica particles have an average particle diameter D50 of 1 μm or more and 30 μm or less, as measured by laser diffraction scattering. The sealing resin composition according to claim 1 or 2.

6. The thermosetting resin includes an epoxy resin. The encapsulating resin composition according to claim 1 or 2.

7. The aforementioned plant-derived silica is silica derived from rice husks. The sealing resin composition according to claim 1 or 2.

8. Semiconductor elements and It is composed of a cured product of the sealing resin composition according to claim 1 or 2, A semiconductor device in which the semiconductor element is sealed by a cured product of the sealing resin composition.

9. The combustion process involves burning plants and collecting the ash, A dissolution step in which silica contained in the ash is dissolved into a solution, An extraction step to extract and remove the dissolved silica, Addition step: Adding the extracted silica to the thermosetting resin as at least a part of the inorganic filler. A method for producing a sealing resin composition, including [the specified element].

10. The extraction step is followed by a washing step of washing the extracted silica. A method for producing a encapsulating resin composition according to claim 9.

Images