Resin composition and sheet molding compound, and alumina particles used in resin composition

Abstract

Provided is a resin composition which contains alumina particles and a resin and which has a lower charge than conventional resin compositions. The resin composition contains alumina particles in which the moisture content generated by heating from 200 DEG C to 900 DEG C is greater than 59.8 ppm, and a resin.

Description

Technical Field

[0001] This disclosure relates to resin compositions and sheet molding compounds, as well as alumina particles used in resin compositions. Background Technology

[0002] Since the heat generated by the energization of electronic components can adversely affect their performance, rapid heat dissipation is desirable. Therefore, it is desirable for materials constituting, for example, semiconductor sealing components surrounding IC chips to exhibit high thermal conductivity for heat dissipation. Such sealing components typically contain inorganic particles (e.g., alumina particles) and resin, as described in Patent Document 1.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-200478 Summary of the Invention

[0006] If dust or other contaminants adhere during the manufacturing of semiconductor devices, it can cause defects. Especially in recent years, with the miniaturization of semiconductor devices and the reduction of wiring spacing, even the adhesion of fine dust particles has become a problem. To more reliably suppress the adhesion of fine dust, the resin composition used in semiconductor sealing components needs to have a further reduced charge compared to the past. However, the specific methods for further reducing the charge of the resin composition compared to the past are not yet known.

[0007] Patent document 1 does not provide a comprehensive study on the charge of the resin composition.

[0008] In view of this situation, one embodiment of the present invention aims to provide a resin composition comprising alumina particles and resin, and having a lower charge than before.

[0009] Another embodiment of the present invention aims to provide a sheet composition (sheet molding compound) composed of such a resin composition.

[0010] Another embodiment of the present invention aims to provide alumina particles for use in a resin composition.

[0011] Embodiment 1 of the present invention is a resin composition comprising alumina particles and resin.

[0012] The alumina particles produced more than 59.8 ppm of water when heated from 200°C to 900°C.

[0013] The second embodiment of the present invention is based on the resin composition of the first embodiment, wherein the amount of water produced by the alumina particles during heating from 200°C to 550°C is greater than 43.0 ppm.

[0014] The third embodiment of the present invention is a resin composition according to embodiment 1 or 2, wherein the absolute value of the charge of the alumina particles is less than 0.17 kV.

[0015] Embodiment 4 of the present invention is a resin composition according to any one of Embodiments 1 to 3, wherein the α-ray content is less than 0.022 cph / cm. 2 .

[0016] Embodiment 5 of the present invention is a resin composition according to any one of Embodiments 1 to 4, wherein the ratio (L2 / L1) of the total length L2 of the internal grain boundaries of the alumina particles to the length L1 of the outer edge is less than 139.1%.

[0017] The sixth embodiment of the present invention is a sheet molding compound composed of the resin composition described in any one of embodiments 1 to 5, with a thickness of 1000 μm or less.

[0018] Method 7 of the present invention is an alumina particle that produces a water content greater than 59.8 ppm when heated from 200°C to 900°C.

[0019] According to one embodiment of the present invention, it is possible to provide a resin composition with a lower charge than in the past.

[0020] According to another embodiment of the present invention, it is possible to provide a sheet molding compound composed of such a resin composition.

[0021] According to another embodiment of the present invention, it is possible to provide alumina particles for use in a resin composition. Detailed Implementation

[0022] To minimize the risk of fine dust adhering to the resin composition, the inventors conducted in-depth research on resin compositions that suppress the charge level to a lower level than before. As a result, they discovered for the first time that by ensuring the alumina particles used in the resin composition contain a certain amount of water, the charge level of the resin composition can be effectively reduced, thus completing this invention.

[0023] Hereinafter, the resin composition of the embodiments, the alumina particles used in the resin composition, and the sheet molding compound (SMC) made of the resin composition will be described.

[0024] [Resin Composition]

[0025] The resin composition of this embodiment comprises alumina particles and resin. The alumina particles used have a water content greater than 59.8 ppm when heated from 200°C to 900°C.

[0026] It should be noted that the term "resin composition" in this specification refers to a resin composition encompassing all states, including a liquid state before the resin in the resin composition is cured, a semi-cured state (stage B) where the resin is partially cured, and a cured state (stage C) where the resin is fully cured. Here, "liquid state" also includes compositions in which the resin composition has a fluidity, such as resin compositions containing solvents described later. "Semi-cured state" refers to a state where the resin composition has cured to the point where it can be treated as a solid, but the surface of the resin composition is tacky due to incomplete curing. "Cureable state" refers to a state where the resin composition is treated as a solid and the surface of the resin composition is almost non-tacky.

[0027] Regarding the charge on a resin composition, the lower the absolute value of the charge, the less likely it is to become charged, and thus, the less likely it is to attract dust. The inventors discovered that by using alumina particles with a controlled moisture content of more than a certain amount to form the resin composition, the absolute value of the charge on the resulting resin composition can be reduced. In particular, in the resin compositions of the embodiments, by using alumina particles with a moisture content greater than 59.8 ppm generated during heating from 200°C to 900°C, the absolute value of the charge on the resin composition can be reduced to 0.00 kV (essentially uncharged). Therefore, the resin compositions of the embodiments can also effectively suppress the adhesion of fine dust.

[0028] The preferred resin composition has an alpha ray content of less than 0.022 cph / cm. 2 This is because semiconductor devices are susceptible to the effects of alpha rays, and malfunctions (soft errors) caused by alpha rays can easily become a problem. Furthermore, if the amount of alpha rays is low, it is expected that the resin composition will not easily become charged due to the ionization effect of alpha rays. Therefore, it is believed that a resin composition with extremely low charge can be formed relatively easily. The alpha ray amount of the resin composition is preferably 0.020 cph / cm. 2 The following is more preferably 0.015 cph / cm 2 The following is a further preferred value: 0.005 cph / cm 2 The following is particularly preferred: 0.002 cph / cm 2 The following is particularly important: the alpha radiation content of the cured resin composition is preferably less than 0.022 cph / cm. 2 0.020 cph / cm 2 Below, 0.015 cph / cm 2 Below, 0.005 cph / cm2 Below or 0.002 cph / cm 2 The lower the alpha radiation content of the resin composition, the better; the preferred lower limit is 0.000 cph / cm. 2 It should be noted that the alpha radiation content of the resin composition is determined in both the semi-cured and cured states, and can be measured using an alpha radiation measuring device (e.g., the Alpha Sciens Model 1950). The measurement area of ​​the sample is set to 1000 cm². 2 The measurement time was set to 99 hours, and PR-10 gas (Ar 90%, CH4 10%) was used for counting.

[0029] The fracture stress measured in the resin composition in the semi-cured or cured state is preferably greater than 41.2 MPa, more preferably 50.0 MPa or more, further preferably 60.0 MPa or more, and particularly preferably 65.0 MPa or more. In particular, the fracture stress of the cured resin composition is preferably greater than 41.2 MPa, 50.0 MPa or more, 60.0 MPa or more, or 65.0 MPa or more in sequence. This improves the strength when manufacturing sealing components and also improves dimensional stability relative to external energy such as heat. It should be noted that the fracture stress of the resin composition can be calculated from the stress-strain curve obtained from the tensile test according to JIS K7161 (2014). The fracture stress of the resin composition in the semi-cured and cured states can be increased by adjusting the content of alumina particles and the curing conditions. Generally, the fracture stress shows a higher value in the cured state than in the semi-cured state.

[0030] The energy absorbed until fracture, measured in the resin composition in the semi-cured or cured state, is preferably 0.200 MPa or more, more preferably 0.314 MPa or more, further preferably 0.400 MPa or more, even more preferably 0.500 MPa or more, and particularly preferably 0.600 MPa or more. In particular, the energy absorbed until fracture of the cured resin composition is preferably greater than 0.314 MPa, 0.400 MPa or more, 0.500 MPa or more, or 0.600 MPa or more, sequentially. This improves the strength when manufacturing sealing components and also enhances dimensional stability relative to external energies such as heat. It should be noted that the energy absorbed until fracture of the resin composition can be calculated from the area enclosed by the stress-strain curve obtained from the tensile test according to JIS K7161 (2014). The energy absorbed until fracture of the resin composition in the semi-cured and cured states can be increased by adjusting the alumina particle content and curing conditions. Generally, the energy absorbed until fracture shows a higher value for the cured resin composition than for the semi-cured state.

[0031] Preferably, the correlation coefficient when linearly approximating the stress-strain curve from fracture to fracture in the semi-cured or cured resin composition is greater than 0.9765. A large correlation coefficient indicates uniform elongation of the resin composition, for example, meaning that the inorganic particles are uniformly dispersed in the resin without agglomeration. In this case, appropriate interactions between the particles and the resin are easily achieved, and dimensional stability relative to external energies such as heat is easily ensured. This correlation coefficient is preferably 0.9780 or higher, more preferably 0.9795 or higher. In particular, the correlation coefficient when linearly approximating the stress-strain curve from fracture to fracture of the cured resin composition is preferably greater than 0.9765, 0.9780 or higher, or 0.9795 or higher, respectively. The upper limit of this correlation coefficient is 1.0000.

[0032] In order to form a resin composition without compromising the inherent flexibility of the resin, the alumina particles are preferably, in order of preference to the total resin composition, 5-75% by volume of resin and 95-25% by volume of alumina particles; or 8-50% by volume of resin and 92-50% by volume of alumina particles; or 10-40% by volume of resin and 90-60% by volume of alumina particles; or 12-40% by volume of resin and 88-60% by volume of alumina particles. Furthermore, in both the semi-cured and cured states of the resin composition, the total proportion of resin and alumina particles relative to the total resin composition is preferably 60% by volume or more, more preferably 70% by volume or more, and even more preferably 80% by volume or more. Moreover, in both the semi-cured and cured states of the resin composition, the proportion of solid components relative to the total resin composition is preferably 80% by volume or more, more preferably 90% by volume or more, and even more preferably 95% by volume or more. The solid components of the resin composition refer to the components that remain as solid components when the resin composition is heated, for example, the components obtained after removing components that evaporate upon heating, such as the solvents mentioned above. On the other hand, components that are liquid at 25°C but are introduced into the solid components of the resin composition during heating are also included in the solid components. The proportion of solid components can be determined, for example, by calculating the amount of solvent in the resin composition and removing it from the whole. The amount of solvent in the resin composition can be determined, for example, by the following method: After measuring the mass W1 (g) of the resin composition, the sample is heated at 150°C for 10 minutes using a fully exhaust oven to evaporate all the solvent contained in the sample. After that, the sample is left at room temperature for 5 minutes to return to room temperature, and the mass W2 (g) of the heated sample is measured. By subtracting W2 (g) from W1 (g), the amount of solvent in the resin composition can be determined.

[0033] Next, the alumina particles and resin constituting the resin composition will be described in detail.

[0034] [Alumina particles]

[0035] The alumina particles of this embodiment have the following characteristics.

[0036] The alumina particles preferably include α-alumina particles. α-alumina is expected to reduce the amount of α-rays emitted by the alumina particles; the presence of α-alumina particles in the alumina particles results in an improved suppression effect on the amount of α-rays emitted by the resin composition. Furthermore, α-alumina particles are also expected to reduce the dielectric loss of the resin composition.

[0037] (Moisture content of alumina particles)

[0038] The alumina particles of the embodiment have a water content (sometimes referred to as "total water content") greater than 59.8 ppm when heated from 200°C to 900°C. By using alumina particles containing a certain amount of water, the charge on the resin composition can be effectively reduced.

[0039] The total moisture content of the alumina particles is preferably 70.0 ppm or more, more preferably 80.0 ppm or more, and particularly preferably 95.0 ppm or more. From the viewpoint of reducing the charge on the resin composition, the upper limit of the total moisture content of the alumina particles is not particularly limited, and can be 200.0 ppm or less.

[0040] The total moisture content of alumina particles, especially the moisture generated during heating from 200°C to 550°C (sometimes referred to as "low-temperature side moisture"), can have a significant impact on the charge on the resin composition.

[0041] The moisture content on the low-temperature side is preferably controlled to be greater than 43.0 ppm, thereby further reducing the charge on the resin composition.

[0042] The moisture content on the low-temperature side of the alumina particles is more preferably 60.0 ppm or more, further preferably 70.0 ppm or more, and particularly preferably 80.0 ppm or more. From the viewpoint of reducing the charge on the resin composition, the upper limit of the moisture content on the low-temperature side of the alumina particles is not particularly limited, and can be 185.0 ppm or less.

[0043] The moisture content (total moisture content and low-temperature moisture content) of the alumina particles was determined based on the Karl Fischer titration method (moisture vaporization-titration method) as described in JIS K 0068:2001 "Methods for determination of moisture content of chemical products".

[0044] (The charge of the alumina particles)

[0045] The alumina particles in the embodiment preferably have an absolute value of charge of 0.17 kV or less. This further reduces the charge on the resin composition and improves the dispersibility of the alumina particles in the resin. That is, since the alumina particles are more uniformly dispersed within the resin composition, the physical properties of the resin composition (fracture stress, absorbed energy up to fracture, and correlation coefficient when linearly approximating the stress-strain curve of the resin composition up to fracture) can be improved.

[0046] The charge on alumina particles is affected by factors such as the water content, surface unevenness, and crystal structure, with water content considered to have a significant impact. Therefore, the charge can be controlled by adjusting the water content of the alumina particles.

[0047] The absolute value of the charge on the alumina particles is more preferably 0.15 kV or less, further preferably 0.10 kV or less, particularly preferably 0.08 kV or less, even more preferably 0.05 kV or less, and most preferably 0.02 kV or less. The lower the absolute value of the charge on the alumina particles, the better, with a preferred lower limit of 0.00 kV.

[0048] The charge on alumina particles is measured using an electrostatic measuring instrument according to JIS C 61340-2-1. For example, commercially available potentiometers, coulometers, and Faraday cages can be used.

[0049] In determining the moisture content and charge of alumina particles in a resin composition, the resin contained in the resin composition can first be removed by dissolving it in an organic solvent, etc., so that only the alumina particles are separated. The separated alumina particles are then used to determine the moisture content and charge.

[0050] (Uranium and thorium content)

[0051] The alumina particles have a uranium content of less than 550 ppb and a thorium content of less than 10 ppb. By suppressing the uranium and thorium content of the alumina particles to extremely low levels as described above, the amount of alpha rays emitted by the alumina particles can be reduced, thereby suppressing the amount of alpha rays emitted by the resin composition. Therefore, when used as a sealing material for semiconductor devices, it is possible to suppress malfunctions of the semiconductor devices caused by alpha rays.

[0052] The uranium content is preferably below 300 ppb, more preferably below 100 ppb, even more preferably below 50 ppb, and particularly preferably below 30 ppb, for example below 10 ppb or 5 ppb. The lower limit of the uranium content is not particularly limited and can be above 0.1 ppb.

[0053] The thorium content is preferably 8 ppb or less, more preferably 5 ppb or less, and particularly preferably 2 ppb or less. There is no particular limitation on the lower limit of the thorium content, which can be 0.1 ppb or more.

[0054] Uranium and thorium contents can be determined by inductively coupled plasma mass spectrometry (ICP-MS).

[0055] (The ratio of the total length L2 of the grain boundaries inside the alumina particle to the length L1 of the outer edge)

[0056] By reducing the content of grain boundaries within alumina particles, the shielding effect against alpha rays generated by uranium and thorium within the alumina particles can be improved, thereby reducing the amount of alpha rays emitted by the alumina particles.

[0057] In this embodiment, the ratio (L2 / L1) of the total length L2 of the grain boundaries to the length L1 of the outer edge is used as an indicator of the content of grain boundaries inside the alumina particles. L1 and L2 are determined by observing the cross-section of the alumina particles.

[0058] When the length of the outer edge of a single alumina particle is defined as L1, and the total length of the grain boundaries of that alumina particle is defined as L2, it can be said that alumina particles with a smaller L2 / L1 ratio have a lower content of grain boundaries and emit a lower amount of alpha rays. Particularly preferred is a (L2 / L1) ratio of less than 139.1%, which further reduces the amount of alpha rays emitted when used as a filler in resin compositions. By reducing the amount of alpha rays emitted by alumina particles, the amount of alpha rays emitted from resin compositions containing alumina particles can also be reduced.

[0059] The ratio (L2 / L1) is preferably 120.0% or less, more preferably 100.0% or less, further preferably 80.0% or less, even more preferably 60.0% or less, particularly preferably 52.0% or less, and most preferably 50.0% or less. The lower limit of (L2 / L1) is not particularly limited and can be 10.0% or more, for example, 20.0% or more, 30.0% or more, 40.0% or more, or 43.0% or more. If the lower limit of L2 / L1 is within the above range, the interaction between particles and resin is more easily achieved, and the mechanical strength, such as the fracture stress, of the semi-cured and cured resin composition is particularly easily improved.

[0060] To control the L2 / L1 ratio within an appropriate range, single-crystal raw material particles can also be used.

[0061] It should be noted that the "total length of grain boundaries L2" is the sum of the grain boundaries contained within the alumina particle, excluding the outer edge of the alumina particle. The total length of grain boundaries L2 is obtained by adding the total length of grain boundaries L3 within the alumina particle to the total length of the inner wall of the voids (when voids exist within the alumina particle) L4 (i.e., L2 = L3 + L4).

[0062] (Particle size of alumina)

[0063] The cumulative particle size D50 of the alumina particles, representing 50% of the cumulative particle size distribution from the microparticle side based on volume, is preferably 100 μm or less, more preferably 50 μm or less, further preferably 20 μm or less, even more preferably 10 μm or less, particularly preferably 5 μm or less, and most preferably 3 μm or less. By keeping D50 within the above range, a resin composition suitable for miniaturization of semiconductor devices and reduction of wiring spacing can be formed.

[0064] Preferably, the ratio of the alumina particles' cumulative particle size D90 (hereinafter sometimes simply referred to as "D90"), representing 90% of the total particle size distribution, to the cumulative particle size D50 (hereinafter sometimes simply referred to as "D50"), representing 50% of the total particle size distribution, is D90 / D50, which is 5.0 or less. This results in a sharper particle size distribution, facilitating appropriate interactions between the particles and the resin, and particularly improving the mechanical strength, such as fracture stress, of the semi-cured and cured resin compositions. For example, D90 / D50 is more preferably 4.0 or less, even more preferably 3.0 or less, and particularly preferably 1.5 or less.

[0065] On the other hand, when the particle size distribution of alumina particles is relatively wide, the filling capacity can be improved by small particles entering the gaps between large particles. Mixing more alumina particles into the resin can improve dimensional stability and fracture stress relative to external energy such as heat. Therefore, D90 / D50 is preferably 1.1 or more, more preferably 1.2 or more, and even more preferably 1.3 or more.

[0066] For the particle sizes D50 and D90 of alumina particles, for example, D50 and D90 can be determined by using the "Microtrac MT3300EXII" manufactured by MicrotracBEL Co., Ltd. as a laser particle size distribution measuring device, and by measuring the particle size distribution of alumina particles using laser diffraction.

[0067] The resin contained in the resin composition can be removed by dissolving it with, for example, an organic solvent, or by thermally decomposing the resin at a temperature of 500°C or higher, thus separating only the alumina particles and using these alumina particles to determine the particle size of the alumina particles in the resin composition.

[0068] Another method for determining the D50 and D90 of alumina particles is image analysis. The resin composition can be cross-sectionally observed using SEM, and image analysis can be performed on all alumina particles contained within a specified observation area (e.g., 200 μm × 200 μm). Based on the measured particle size (equivalent circle diameter), the particle size corresponding to D50 and D90 can be calculated.

[0069] [Method for manufacturing alumina particles]

[0070] The alumina particles of this embodiment can be manufactured, for example, by the method described below.

[0071] (Raw material: alumina)

[0072] Alumina can be produced using well-known methods. Examples include the Bayer process, the ammonium alum process, the aluminum ammonium carbonate process (AACH process), solvent extraction, organoaluminum hydrolysis (aluminum alkoxide process), the CZ process, the molten flame process, the bubble growth process, the Bridgman process, and the EFG process, among other melt growth methods.

[0073] In the case of the Bayer process, aluminum hydroxide obtained from bauxite can be calcined to produce raw alumina. Alternatively, high-purity raw alumina with low uranium and thorium content can be produced using the ammonium alum process, AACH process, solvent extraction process, and aluminum alkoxide process, which are therefore preferred. If raw alumina produced by these methods, with uranium content suppressed to, for example, less than 550 ppb and thorium content suppressed to, for example, less than 10 ppb, is used to produce alumina particles, alumina particles with suppressed uranium and thorium content can be obtained, which is also preferred.

[0074] (Pulverization of raw material alumina)

[0075] To easily obtain alumina particles of the desired size for flame melting, raw alumina is pulverized to obtain alumina raw material powder for flame melting. The pulverization of raw alumina can be carried out by known methods such as vibratory mills, bead mills, ball mills, and jet mills, and can be performed in either dry or wet conditions.

[0076] In the above-mentioned pulverization process, a surface protectant can be used. The surface protectant not only protects the surface of the pulverized alumina raw material powder, but also has the function of deactivating the surface of the alumina raw material powder. By deactivating the surface, the surface protectant can reduce the agglomeration of the alumina raw material powder, thus making it suitable for using easily agglomerated raw alumina with a high BET specific surface area to obtain alumina particles of the target particle size after flame melting. Suitable surface protectants include, for example, monohydric alcohols such as methanol, ethanol, 1-propanol, and 2-propanol; diols such as ethylene glycol, polyethylene glycol, propylene glycol, and polypropylene glycol; amines such as triethanolamine; and higher fatty acids such as palmitic acid, stearic acid, and oleic acid. One of these surface protectants can be used alone, or two or more can be used in combination. Among them, diols are preferred, and one or more of ethylene glycol, polyethylene glycol, propylene glycol, and polypropylene glycol are particularly preferred.

[0077] There are no particular limitations on the molecular weight of polyethylene glycol and polypropylene glycol, which are preferred as surface protectants. However, liquids with an average molecular weight of around 200 to 600 are preferred for ease of addition.

[0078] When the raw material alumina is set at 100 parts by weight, in order to fully exert the effect of the surface protectant, the amount of surface protectant added is preferably 0.01 parts by weight or more. In addition, even if too much surface protectant is added, the effect of the surface protectant will be saturated, so it is preferred to add 10 parts by weight or less. The amount of surface protectant added is more preferably 0.05 to 8 parts by weight, and even more preferably 0.1 to 5 parts by weight.

[0079] (Flame melting)

[0080] Flame melting refers to a method in which raw alumina is sprayed into a flame and then cooled and solidified after dropletization. According to flame melting, alumina particles can be obtained while maintaining the particle size of the raw alumina. In flame melting, the temperature of the flame melting furnace is preferably 1000°C or higher. In flame melting, the raw material feed rate can be appropriately adjusted; by setting it preferably to 50 kg / h or less, and more preferably 10 kg / h or less, the thermal energy applied to the alumina particles can be controlled within a specified range, thus easily obtaining alumina particles that meet the aforementioned requirements.

[0081] After the flame melts, alumina particles can be captured by a cyclone separator or a bag filter and graded to obtain alumina particles with the desired properties.

[0082] The moisture content of the alumina particles can be controlled by the manufacturing method of the raw alumina, the crushing method, or the conditions of the flame melting method, or by immersing the obtained alumina particles in an acidic solution such as hydrochloric acid. For ease of concentration adjustment, hydrochloric acid is preferred as the acidic solution for immersion. The concentration of the acidic solution is preferably adjusted to 1M to 12M, more preferably to 1M to 10M, and particularly preferably to 2M to 5M. The mass ratio of alumina particles to acidic solution during immersion is preferably 1:2 to 1:10. The immersion time is preferably 5 hours or more. Heating can be appropriately applied during immersion in a way that shortens the immersion time, for example, heating to 50 to 90°C. After immersion, washing and drying are preferred.

[0083] [Resin]

[0084] The resin used in the resin composition preferably includes one or more selected from epoxy resins and thermoplastic polyimides, and more preferably includes epoxy resins. Examples of preferred epoxy resins include mesocrystalline epoxy resins, phenylcyclohexyl epoxy resins, naphthalene-based epoxy resins, phenolic epoxy resins, biphenyl epoxy resins, butadiene-based epoxy resins, and bisphenol A epoxy resins. Mesocrystalline epoxy resins are epoxy resins having mesocrystalline groups, and preferably resins that exhibit a phase transition temperature and liquid crystal properties within a temperature range of 100°C to 200°C during encapsulation. It should be noted that the resin included in the resin composition may include one or more epoxy resins. That is, the resin included in the resin composition may include one or more epoxy resins selected from mesocrystalline epoxy resins, phenylcyclohexyl epoxy resins, naphthalene-based epoxy resins, phenolic epoxy resins, biphenyl epoxy resins, butadiene-based epoxy resins, and bisphenol A epoxy resins, and may further include thermoplastic polyimides. These resins are expected to shield against alpha rays emitted by alumina particles, thus yielding resin compositions with lower alpha ray content.

[0085] Furthermore, these resin compositions may contain, as needed and within a range that does not impair the effects of the invention, two or more known additives such as plasticizers, curing agents, curing accelerators, coupling agents, fillers, pigments, flame retardants, antioxidants, surfactants, compatibilizers, weathering agents, anti-blocking agents, antistatic agents, leveling agents, and release agents, either alone or in combination. Additionally, as an embodiment of this application, the resin composition (especially liquid or semi-cured resin compositions) may contain a solvent. When the resin composition contains a solvent, it flows easily, can be easily deformed to match the fine structure of the IC chip and substrate, and can encapsulate dense structures without gaps. As a solvent, known solvents can be used; there are no limitations as long as the solvent can dissolve the aforementioned resin. Examples include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, amine-based solvents, amide-based solvents, halogen-based solvents, hydrocarbon-based solvents, and nitrile-based solvents. From the viewpoint that the resin composition is a good solvent relative to epoxy resin and has excellent coatability, ketone-based and ester-based solvents are preferred.

[0086] In a preferred embodiment of the present invention, the resin composition comprises alumina particles, epoxy resin, solvent, and curing agent. Examples of curing agents include amine-based curing agents such as 4,4-diaminodiphenylmethane.

[0087] [Method for manufacturing the resin composition]

[0088] The method for manufacturing the resin composition is described.

[0089] A resin composition can be obtained by mixing the alumina particles of this embodiment with a resin using a generally known method. For example, if the resin is liquid (e.g., liquid epoxy resin), the resin composition can be obtained by mixing the liquid resin with alumina particles and a curing agent and then curing it using heat or ultraviolet light. Known curing agents and methods can be used as the curing agent, mixing method, and curing method. On the other hand, if the resin is solid (e.g., epoxy resin, polyolefin resin, or acrylic resin), the target resin composition can be obtained by mixing the alumina particles with the resin and then mixing it using a known method such as melt mixing, or by dissolving the resin, alumina particles, and curing agent in a solvent and mixing them. The resin composition may contain a solvent.

[0090] The resin composition of this embodiment includes all states of the resin composition, including a liquid state before the resin in the resin composition is cured, a semi-cured state (stage B) where the resin is partially cured, and a cured state (stage C) where the resin is fully cured.

[0091] The liquid resin composition comprises a complex of alumina powder and resin in a specified ratio, a mixture of the complex, and a molded article obtained by molding the mixture.

[0092] A semi-cured resin composition comprises a resin composition obtained by semi-curing a resin contained in a mixture or molded article.

[0093] The cured resin composition comprises a resin composition obtained by completely curing the resin contained in a mixture, molded article, or semi-cured article.

[0094] [Sheet molding compound (SMC)]

[0095] The resin compositions described in the embodiments can be used to provide sheet molding compounds (SMCs). SMCs are resin compositions molded into sheets. SMCs preferably have flowability when heated and pressurized, but can also be in a semi-cured state.

[0096] The thickness of SMC is preferably 1000 μm or less. When mounted in a semiconductor device, it enables miniaturization and weight reduction of the semiconductor device. Furthermore, it improves the hermeticity when packaging IC chips. More preferably, the thickness is 800 μm or less; even more preferably, 600 μm; still more preferably, 500 μm or less; particularly preferably, 400 μm or less; and especially more preferably, 300 μm or less. The lower limit of the thickness is not particularly limited. From the viewpoint of improving the size of commonly used SMC and the hermeticity of IC chips, it can be, for example, 10 μm or more, 50 μm or more, and further, 100 μm or more, or 150 μm or more.

[0097] SMC can be manufactured using known methods. As an example, it is obtained by coating an uncured resin composition onto a substrate and then semi-curing the resin composition by depositing a protective film thereon. Alternatively, as another example, it is obtained by coating an uncured resin composition containing a solvent onto a substrate, removing the solvent from the resin composition by drying or the like, and then depositing a protective film. In the use of SMC, after peeling off the protective film, bonding the wafer, etc., the substrate is removed, and post-curing is performed.

[0098] The resin composition and SMC of the present invention are suitable as sealing components for semiconductor devices due to their low alpha ray content.

[0099] Example

[0100] [Preparation of alumina particles]

[0101] The alumina particles (A-C) used in the resin compositions of samples No. 1 to 5 were prepared as follows.

[0102] (Alumina particles A and B used in samples No. 1 to 4)

[0103] As alumina particles, prepare alumina particles A (used in samples No. 3-4) and alumina particles B (used in samples No. 1-2).

[0104] The alumina used as raw material was γ-alumina obtained by the ammonium alum method (the average particle size of the primary particles, calculated based on the BET specific surface area value below, was 13 nm). The BET specific surface area of ​​this γ-alumina, based on the nitrogen adsorption method, was 120 m². 2 / g. Before pulverization, 4% by mass of propylene glycol is added to the raw alumina as a surface protectant and mixed.

[0105] Next, the material was processed using a jet mill (PJM-280SP horizontal jet mill manufactured by Nippon Pneumatic Industries, Ltd.) at a feed rate of 30 kg / h for the raw alumina and a gauge pressure of 0.5 MPa at the air supply port during grinding, to obtain alumina raw material powder with an average particle size of about 2 μm for the secondary particles.

[0106] The obtained alumina raw material powder was fed into a flame melting furnace to melt it and obtain spherical alumina particles. The atmosphere temperature in the flame melting furnace was set to 1250℃, and the raw material feed rate was set to 5 kg / h. The obtained alumina particles were recovered using a cyclone separator and classified by the cyclone separator to remove particles larger than 20 μm, obtaining alumina particles A (D50 = 5.1 μm, used in samples No. 3-4). Furthermore, particles larger than 10 μm were removed to obtain alumina particles B (D50 = 2.3 μm, used in samples No. 1-2).

[0107] (Alumina particles C used in sample No. 5)

[0108] Alumina particles (alumina particles C) made by Denka DAW05 were used in sample No. 5.

[0109] The following determinations were made on the alumina particles used in each sample.

[0110] [Particle size distribution of alumina particles]

[0111] The D50 and D90 of alumina particles were determined using a Microtrac MT3300EXII laser particle size distribution measuring device manufactured by MicrotracBEL Co., Ltd., employing laser diffraction. Based on the particle size distribution measurement results, D50 and D90 were calculated. The sample used for the measurement was an alumina particle dispersion obtained by adding alumina particles to a 0.2% (w / w) sodium hexametaphosphate aqueous solution in a manner appropriate to the laser scattering intensity, and then dispersing the particles using the device's built-in ultrasonic wave at 40W for 5 minutes. The refractive index of alumina is 1.76.

[0112] [The electric charge of alumina particles]

[0113] The charge on alumina particles was measured using an electrostatic meter under the following conditions.

[0114] Electrostatic meter: FMX-004 (SIMC0 manufactured)

[0115] Measurement mode: Low MDDE

[0116] Temperature 23℃, humidity 40%

[0117] Take 10g of each alumina particle and place it in an aluminum cup. Set up an electrostatic meter at a distance of 25mm from the surface and measure the charged potential. Define the obtained charged potential value as the charge.

[0118] [Moisture content of alumina particles]

[0119] The moisture content of alumina particles was determined based on the Karl Fischer titration method (moisture vaporization-titration method) as described in JIS K 0068:2001 "Methods for determination of moisture content of chemical products". In the determination of moisture content, two components were measured: the moisture content generated during heating from 200°C to 550°C (low-temperature moisture content) and the moisture content generated during heating from 200°C to 900°C (total moisture content).

[0120] [Determination of the combined length L1 of the outer edge of the alumina particle and L2 of the grain boundary within the particle]

[0121] Alumina particles from samples No. 1 to 5 were used to prepare cross-sectional observation specimens. In the preparation of these specimens, alumina particles were embedded in resin, and then the resin and alumina particles were cut using a diamond cutter. A Pt protective film was then deposited onto the cross-section, and the cross-section was prepared using Ar ion polishing. The specimens were then fixed to the SEM sample stage using Cu double-sided tape, and SEM-EBSD measurements were performed without deposition. The observation position was determined so that at least two alumina particles completely fell within the observation area (i.e., at least two alumina particles did not contact the frame of the observation area). All alumina particles measured were α-alumina particles.

[0122] The following instruments were used in sample pretreatment and EBSD determination.

[0123] Using instruments

[0124] Ion milling device: IM-4000 (manufactured by Hitachi, Ltd.)

[0125] Ion sputtering equipment: E-1030 (manufactured by Hitachi, Ltd.)

[0126] Ultra-high resolution field emission scanning electron microscope: JSM-7800F Prime (manufactured by Nippon Electron Ltd.)

[0127] Backscattered electron diffraction apparatus: Digiview V (TSL fabrication)

[0128] The conditions for EBSD determination are as follows.

[0129] Measurement area: 500.0 μm × 400.0 μm

[0130] Accelerating voltage: 20.0kV

[0131] Magnification:×500

[0132] Vacuum degree: 30Pa

[0133] In the obtained EBSD image, select two or more alumina particles that do not contact the observation area. The average length L1 of the outer edge of each alumina particle is calculated using ImageJ (made by the National Institute of Health) image processing software. The "total grain boundary length L2" is the sum of the grain boundaries contained within the alumina particle, excluding the outer edge of the alumina particle. The total grain boundary length L2 is obtained by adding the total length of the grain boundaries within the alumina particle to the total length of the inner wall of any void (if a void exists within the alumina particle).

[0134] The ratio (L2 / L1) of the total length of grain boundaries L2 to the length of the outer edge is expressed as a percentage (%). The more grain boundaries and voids inside the alumina particle, the larger the value of L2 / L1 (%).

[0135] [Uranium and thorium content of alumina particles]

[0136] The uranium (U) and thorium (Th) content in alumina particles was determined as follows. First, alumina particles were dissolved in a mixed aqueous solution of sulfuric acid and phosphoric acid by heating. This aqueous solution was then contacted with a cyclohexane solution of tributyl phosphate, a commonly used uranium extractant, to extract the uranium. The uranium transferred to the aqueous phase by back-extraction with pure water was then determined by ICP-MS based on the intensities of U238amu and Th232amu. It should be noted that standard solutions manufactured by SPEX were used to prepare the standard curve.

[0137] [Amount of alpha rays emitted by alumina particles]

[0138] The amount of alpha rays emitted by alumina particles was measured using a Model 1950 measuring apparatus (manufactured by Alpha Sciens). The measurement area of ​​the sample was set to 1000 cm². 2 The measurement time was set to 99 hours, and PR-10 gas (Ar 90%, CH4 10%) was used for counting.

[0139] [Preparation of the resin composition]

[0140] Alumina particles, resin, and other materials were mixed to prepare resin compositions (samples No. 1-5). The types of resins used are listed in Table 1, and the amounts of alumina particles are listed in Table 3.

[0141] The resin compositions for samples No. 1 to 5 were prepared according to the following method. The term "resin composition" in Table 5 refers to the resin composition in its cured state.

[0142] (Samples No. 1 to 5)

[0143] (1) Preparation of varnish

[0144] Dissolve the resins shown in Table 1 in the solvents shown in Table 1 to prepare a 30% by mass mixed solution. Then, add 0.074% by mass of a curing agent (4,4-diaminodiphenylmethane (TCI)) relative to 100% by mass of the mixed solution to prepare a varnish.

[0145] (2) Preparation of alumina / varnish mixture

[0146] Alumina particles were added to the obtained varnish, and the mixture was kneaded using a rotary mixer (Thinky Corporation) to prepare an alumina / varnish mixture.

[0147] (3) Film Forming

[0148] The obtained alumina / varnish mixture was coated onto a PET substrate, and a film was formed using a coating tool to achieve a film thickness of 150-200 μm after heat curing, thus obtaining the resin composition before curing.

[0149] (4) Thermosetting

[0150] The obtained resin composition before curing was left to stand at room temperature for 1 hour, then heated at 140°C for 15 minutes. Following this, it was vacuum-pressed at 140°C for 20 minutes using a pressure molding machine at 0.5 MPa, and then heat-cured at 180°C for 120 minutes under normal pressure. This yielded the cured resin compositions (samples No. 1-5). In the resin compositions of samples No. 1-5, the proportion of solid components relative to the total resin composition was 95% by volume or more.

[0151]

[0152] The details of the types of resins listed in Table 1 are as follows.

[0153] Mesocrystalline epoxy resin (A)

[0154] A prepolymer obtained by reacting trans-4-{4-(2,3-epoxypropoxy)phenyl}cyclohexyl=4-(2,3-epoxypropoxy)benzoate (an epoxy resin represented by the following structural formula) with 6-hydroxy-2-naphthoic acid.

[0155]

[0156] A mixture of JP-100 and HP6000

[0157] It is made by mixing JP-100 of epoxidized polybutadiene (manufactured by Nippon Soda) and HP-6000 of naphthalene-based epoxy resin (manufactured by DIC) at a mass ratio of 1:9.

[0158] [Electricity of resins and resin compositions]

[0159] The charge on resins and resin compositions is measured using an electrostatic meter under the following conditions.

[0160] Electrostatic meter: FMX-004 (SIMC0 manufactured)

[0161] Measurement mode: Low MDDE

[0162] Temperature 23℃, humidity 40%

[0163] For a 10cm square test piece, an electrostatic meter is placed at a distance of 25mm from the surface to measure the charged potential. The obtained charged potential value is defined as the charge.

[0164] [Amount of alpha rays emitted by the resin composition]

[0165] The amount of alpha rays emitted by alumina particles was measured using a Model 1950 measuring apparatus (manufactured by Alpha Sciens). The measurement area of ​​the sample was set to 1000 cm². 2 The measurement time was set to 99 hours, and PR-10 gas (Ar 90%, CH4 10%) was used for counting.

[0166] [The fracture stress of the resin composition, the absorbed energy at fracture, and the correlation coefficient of the stress-strain curve at fracture]

[0167] The fracture stress, absorbed energy at fracture, and correlation coefficient of the stress-strain curve at fracture of the resin composition were determined according to JIS K7161 (2014). Specifically, tensile tests were performed under the following conditions, and the obtained stress-strain curves were analyzed and calculated.

[0168] Experimental apparatus; Autograph AGS-X (manufactured by Shimadzu Corporation)

[0169] Load sensor: 1kN

[0170] Test piece size: 100mm × 10mm

[0171] Test environment: 22℃ / 59%RH

[0172] Analysis software: TRAPEZIUMX

[0173] If the resin composition has a high fracture stress, it can improve the strength when made into a sealing component, and also improve the dimensional stability relative to external energy such as heat.

[0174] If the energy absorbed up to the point of fracture of the resin composition is high, the strength when it is made into a sealing component can be improved, and the dimensional stability relative to external energies such as heat can also be improved.

[0175] If the correlation coefficient is large when linearly approximating the stress-strain curve of the resin composition up to fracture, it indicates that the resin composition elongates uniformly. For example, it could mean that the inorganic particles are uniformly dispersed in the resin without agglomerating with each other.

[0176] The fracture stress of the resin composition can be directly determined from the fracture point of the stress-strain curve.

[0177] The absorbed energy up to the point of fracture of the resin composition is calculated based on the area enclosed by the stress-strain curves obtained from the tensile test.

[0178] The correlation coefficient of the stress-strain curve from the start of the test to fracture, when linearly approximated, was determined using analytical software. It should be noted that the maximum correlation coefficient is 1.0000 (the case where the stress-strain curve is a straight line from the start of the test to fracture).

[0179] The various test results of alumina particles are shown in Tables 2 and 3, the types of resins used and their charge are shown in Table 4, and the various test results of resin compositions are shown in Table 5.

[0180]

[0181]

[0182]

[0183]

[0184] The measurement results are analyzed below.

[0185] The resin compositions of samples No. 1 to 4, which meet the requirements of the embodiments of this application, have a charge of 0.00 kV. On the other hand, the resin composition of sample No. 5, which does not meet the requirements of the embodiments of this application, has a charge of -0.01 kV, which cannot be 0.00 kV.

[0186] Furthermore, since the absolute values ​​of the charge of the alumina particles used in the resin compositions of samples No. 1 to 4 are relatively small, it is considered that the alumina particles in the resin are well dispersed. As a result, the fracture stress of the resin composition is higher. In addition, the correlation coefficients of the absorbed energy up to fracture and the stress-strain curve up to fracture are also good results.

[0187] On the other hand, since the absolute value of the charge of the alumina particles used in the resin composition of sample No. 5 is relatively large, it is believed that the dispersibility of alumina particles in the resin is reduced, and the fracture stress of the resin composition is lower. The correlation coefficients of the absorbed energy at fracture and the stress-strain curve at fracture of the resin composition are lower compared with those of the resin compositions of samples No. 1 to No. 4.

[0188] Regarding the alpha ray radiation, the resin compositions of samples No. 1 to 4 had lower levels, while the resin composition of sample No. 5 had higher levels.

Claims

1. A resin composition comprising alumina particles and resin, The alumina particles produce more than 59.8 ppm of water when heated from 200°C to 900°C.

2. The resin composition according to claim 1, wherein, The alumina particles produce more than 43.0 ppm of water when heated from 200°C to 550°C.

3. The resin composition according to claim 1, wherein, The absolute value of the charge of the alumina particles is less than 0.17 kV.

4. The resin composition according to claim 1, wherein, Alpha ray dose less than 0.022 cph / cm 2 .

5. The resin composition according to claim 1, wherein, The ratio of the total length L2 of the internal grain boundaries of the alumina particles to the length L1 of the outer edge, L2 / L1, is less than 139.1%.

6. A sheet molding compound, comprising the resin composition according to any one of claims 1 to 5, The thickness is less than 1000μm.

7. An alumina particle that produces more than 59.8 ppm of water when heated from 200°C to 900°C.

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