Resin composition and sheet molding compound

Abstract

Provided is a resin composition comprising inorganic particles and a resin, the resin composition being capable of suppressing dimensional changes when repeatedly heated. The resin composition includes inorganic particles and a resin, has a fracture stress of more than 41.2 MPa, and has an absorption energy up to the fracture of more than 0.314 MPa.

Description

Resin composition and sheet molding compound

[0001] The present disclosure relates to resin compositions and sheet molding compounds.

[0002] Since heat generated by passing current through electronic components tends to adversely affect the performance of the electronic components, it is desirable for the heat to be dissipated quickly. Therefore, for example, it is desirable for a material constituting a semiconductor encapsulation member surrounding an IC chip to exhibit high thermal conductivity for heat dissipation. Such an encapsulation member may generally contain inorganic particles and a resin, as described in Patent Document 1.

[0003] Japanese Patent Application Laid-Open No. 2020-200478

[0004] In recent years, with the miniaturization of semiconductor devices and the narrowing of wiring pitches, stricter requirements have been placed on the encapsulating material with respect to dimensional change due to heat. In particular, semiconductor devices can be repeatedly exposed to high temperatures due to current flow, and it has become a problem that the dimensions of the encapsulating material change significantly when repeatedly heated. In the prior art such as that described in Patent Document 1, suppression of dimensional change when repeatedly heated has not been considered.

[0005] In view of the above, an object of one embodiment of the present invention is to provide a resin composition containing inorganic particles and a resin, which is capable of suppressing dimensional change when repeatedly heated.Another embodiment of the present invention is to provide a sheet-shaped composition (sheet molding compound) made of such a resin composition.

[0006] A first aspect of the present invention is a resin composition comprising inorganic particles and a resin, having a breaking stress of more than 41.2 MPa and an absorbed energy to break of more than 0.314 MPa.

[0007] A second aspect of the present invention is the resin composition according to the first aspect, wherein a correlation coefficient when a stress-strain curve up to break is linearly approximated exceeds 0.9765.

[0008] In the third aspect of the present invention, the alpha dose is 0.022 cph / cm ２3. The resin composition according to claim 1, wherein the tensile strength is less than 1000 ppm.

[0009] A fourth aspect of the present invention is the resin composition according to any one of the first to third aspects, wherein the inorganic particles have a strain at break of less than 0.113 in a particle compression test.

[0010] A fifth aspect of the present invention is the resin composition according to any one of the first to fourth aspects, wherein the inorganic particles have a breaking strength of less than 1080 MPa in a particle compression test.

[0011] A sixth aspect of the present invention is the resin composition according to any one of the first to fifth aspects, wherein the inorganic particles have an absorbed energy of less than 61.0 MPa until fracture in a particle compression test.

[0012] A seventh aspect of the present invention is the resin composition according to any one of the first to sixth aspects, wherein the inorganic particles have a ratio of the number of isolated OH groups to the number of hydrogen-bonded OH groups of less than 0.39.

[0013] In an eighth aspect of the present invention, the inorganic particles have a number of isolated OH groups of 3.1 / nm ２ 8. The resin composition according to any one of Aspects 1 to 7, wherein the total mass of the resin composition is less than 1000 MPa.

[0014] A ninth aspect of the present invention is a sheet molding compound comprising the resin composition according to any one of the first to eighth aspects, and having a thickness of 1000 μm or less.

[0015] According to an embodiment of the present invention, it is possible to provide a resin composition containing inorganic particles and a resin, which is capable of suppressing dimensional changes when repeatedly heated, and a sheet molding compound made of the resin composition.

[0016] 1 is an example of a plot of strain-strength (MPa) obtained by carrying out a compression test on inorganic particles in accordance with JIS R1639-5.

[0017] The present inventors conducted extensive research to realize a resin composition that can suppress dimensional change when repeatedly heated. As a result, they found that by controlling the breaking stress and the absorbed energy until breakage of a resin composition containing inorganic particles and a resin to be greater than a predetermined value, dimensional change when repeatedly heated can be suppressed. This is thought to be because, by controlling the breaking stress of the resin composition to be greater than a predetermined value, the resin composition becomes less susceptible to fracture, and by controlling the absorbed energy until breakage of the resin composition to be greater than a predetermined value, toughness is improved and shape recovery performance can be ensured, resulting in improved dimensional stability against external energy such as heat.

[0018] The resin composition according to this embodiment and a sheet molding compound (SMC) comprising the resin composition are described below. In this specification, the term "resin composition" is intended to encompass all states of resin compositions, including a liquid state before the resin in the resin composition is cured, a semi-cured state (B stage) in which the resin is semi-cured, and a cured state (C stage) in which the resin is completely cured. The term "liquid state" also includes compositions in which the resin composition has fluidity, such as resin compositions containing solvents, as described below. The "semi-cured state" refers to a state in which the resin composition has cured to the extent that it can be handled as a solid, but is not completely cured, and therefore the surface of the resin composition remains tacky. The "cured state" refers to a state in which the resin composition can be handled as a solid and has almost no tackiness on its surface.

[0019] [Resin Composition] The resin composition according to this embodiment contains inorganic particles and a resin, and has a breaking stress of more than 41.2 MPa and an absorbed energy to break of more than 0.314 MPa, which can suppress dimensional changes when repeatedly heated.

[0020] The rupture stress of the resin composition is measured in a semi-cured or cured state. The rupture stress of the resin composition is preferably 50.0 MPa or more, more preferably 60.0 MPa or more, and even more preferably 65.0 MPa or more. In particular, it is preferable that the rupture stress of the cured resin composition is greater than 41.2 MPa, 50.0 MPa or more, 60.0 MPa or more, or 65.0 MPa or more, in that order. This improves the strength of the resulting sealing member and also improves dimensional stability against external energy such as heat. The rupture stress of the resin composition can be calculated from a stress-strain curve obtained in a tensile test in accordance with JIS K7161 (2014). The rupture stress of the semi-cured and cured resin compositions can be increased by adjusting the content of inorganic particles and the curing conditions. Typically, the rupture stress of a cured resin composition is higher than that of a semi-cured resin composition.

[0021] The absorption energy of the resin composition until breakage is measured for the resin composition in a semi-cured or cured state. The absorption energy of the resin composition until breakage is preferably 0.400 MPa or more, more preferably 0.500 MPa or more, and even more preferably 0.600 MPa or more. In particular, it is preferable that the absorption energy until breakage of the cured resin composition is greater than 0.314 MPa, 0.400 MPa or more, 0.500 MPa or more, or 0.600 MPa or more, in that order. This improves the strength of the resin composition when used as a sealing member, and also improves dimensional stability against external energy such as heat. The absorption energy until breakage of the resin composition can be calculated from the area enclosed by the stress-strain curve obtained in a tensile test in accordance with JIS K7161 (2014). The absorption energy until breakage of the resin composition in a semi-cured or cured state can be increased by adjusting the content of inorganic particles and the curing conditions. Typically, the absorption energy until breakage is higher for a resin composition in a cured state than for a resin composition in a semi-cured state.

[0022] The stress-strain curve of the resin composition up to fracture is measured with the resin composition in a semi-cured or cured state. When the stress-strain curve of the resin composition up to fracture is linearly approximated, the correlation coefficient preferably exceeds 0.9765. A large correlation coefficient indicates that the resin composition stretches uniformly, and may mean, for example, that the inorganic particles are uniformly dispersed in the resin without agglomeration. In this case, appropriate particle-resin interactions are facilitated, making it easier to ensure dimensional stability against external energy such as heat. The correlation coefficient is preferably 0.9780 or greater, and more preferably 0.9795 or greater. When the stress-strain curve of the cured resin composition up to fracture is linearly approximated, the correlation coefficient is preferably greater than 0.9765, 0.9780 or greater, or 0.9795 or greater, in that order. The upper limit of the correlation coefficient is 1.0000.

[0023] The alpha dose of the resin composition is 0.022 cph / cm ２ It is preferable that the α dose of the resin composition is less than 0.020 cph / cm. This is because semiconductor devices are easily affected by α rays, and malfunctions (soft errors) caused by α rays are likely to become a problem. Furthermore, a low α dose reduces damage to semiconductor elements, makes it easier to maintain adhesion at the interface between the resin composition and the elements, and makes it easier to suppress deformation due to thermal history. The α dose of the resin composition is preferably 0.020 cph / cm. ２ or less, more preferably 0.015 cph / cm ２ More preferably, 0.005 cph / cm or less ２ Below 0.002 cph / cm, particularly preferably ２ In particular, the alpha dose of the cured resin composition is 0.022 cph / cm or less. ２ Less than 0.020 cph / cm ２ Below, 0.015cph / cm ２ Below, 0.005cph / cm ２ or less than 0.002 cph / cm ２ The lower the α dose of the resin composition, the more preferable it is, and the preferred lower limit is 0.000 cph / cm ２The alpha dose of the resin composition is measured in a semi-cured or cured state using an alpha ray measuring device (e.g., Model 1950 manufactured by Alpha Sciences). The measurement area of ​​the sample is 1000 cm. ２ The measurement time was 99 hours, and the counting gas was PR-10 gas (Ar 90%, CH ４ 10%) is used.

[0024] The elastic modulus of the resin composition is measured in a semi-cured or cured state. The elastic modulus (tensile modulus) of the resin composition is preferably 2.0 GPa or more. The elastic modulus of the resin composition is more preferably 3.0 GPa or more, even more preferably 4.0 GPa or more, particularly preferably 5.0 GPa or more, even more particularly preferably 6.0 GPa or more, and most preferably 7.0 GPa or more. In particular, the elastic modulus of the cured resin composition is preferably 2.0 GPa or more, allowing for the formation of a sealing member that can withstand deformation under typical usage conditions. The elastic modulus of the resin composition can be calculated from a stress-strain curve obtained in a tensile test in accordance with JIS K7161 (2014). The elastic modulus of the resin composition in the semi-cured and cured states can be increased by adjusting the content of inorganic particles and the curing conditions. Typically, the elastic modulus of a resin composition in the cured state is higher than that of a resin composition in the semi-cured state.

[0025] Preferred inorganic particles are ceramics such as silica, alumina, aluminum nitride, boron nitride, silicon nitride, and silicon carbide. Particles made of inorganic materials with high thermal conductivity are particularly preferred, for example, particles made of inorganic materials with a thermal conductivity of 15 W / mK or more. Suitable inorganic materials include ceramics such as alumina, aluminum nitride, boron nitride, silicon nitride, and silicon carbide. The inorganic particles are preferably ceramic particles. Because ceramics have high thermal conductivity, the use of ceramic particles can improve the heat dissipation performance of the resin composition. Furthermore, when insulating ceramics are used as inorganic particles, short circuits in semiconductor devices can be suppressed. Therefore, insulating ceramic particles are more preferred, and specifically, alumina, aluminum nitride, boron nitride, and silicon nitride are more preferred. Among these, alumina is even more preferred due to its low price. Furthermore, the inorganic particles preferably include α-alumina particles. Alpha-alumina is expected to have the effect of reducing the amount of alpha rays emitted from the inorganic particles, and the presence of alpha-alumina particles in the inorganic particles can result in an improved effect of suppressing the amount of alpha rays emitted from the resin composition.

[0026] The resin composition according to the present embodiment can suppress dimensional change when repeatedly heated, even when using low-strength particles that are relatively easy to manufacture or obtain (low-cost), by satisfying the above-mentioned specific requirements for the breaking stress and the absorption energy until breakage discovered by the present inventors. For example, even when the resin composition according to the present embodiment contains inorganic particles that exhibit small strain at break in a particle compression test, satisfying the above-mentioned specific requirements can suppress dimensional change when repeatedly heated. That is, when the resin composition according to the present embodiment contains inorganic particles that exhibit a strain at break of less than 0.113 in a particle compression test, the effects of the present invention are more pronounced. When the resin composition contains inorganic particles that exhibit a strain of 0.110 or less, the effects of the present invention are even more pronounced. When the resin composition contains inorganic particles that exhibit a strain of 0.100 or less, the effects of the present invention are even more pronounced. The lower limit of the strain is not particularly limited, but it can be, for example, 0.050 or more.

[0027] The strain at the time of fracture of inorganic particles is measured as follows. First, a compression test of inorganic particles is conducted in accordance with JIS R1639-5 to obtain a plot of displacement vs. test force. The displacement of the plot is converted to strain based on the following formula (1), and the test force of the plot is converted to strength based on the following formula (2), to obtain a plot of strain vs. strength (MPa) as shown in Figure 1. Strain = Displacement [μm] / D [μm] (1) Strength [MPa] = 2.48 × Test Force [N] / (π × D ２ ) (2) where D [μm] is the average value of the major axis and the minor axis of the inorganic particles to be tested. The major axis and the minor axis can be measured by observation with an optical microscope.

[0028] In FIG. 1, if there is one region where the slope is constant, the minimum displacement where the displacement exceeds 0 and the slope is constant is defined as the breaking point P １ Breaking point P １ Distortion d in １ is the strain at the time of fracture in the compression test of the particle. If there are multiple regions with a constant slope, the starting point of the region where the difference in strain between the end point and the starting point of the region is the largest is defined as the fracture point P １ The compression test of inorganic particles in a resin composition can be performed by removing the resin contained in the resin composition, for example, by dissolving it in an organic solvent or by heating it to a temperature of 500°C or higher to thermally decompose the resin, and isolating only the inorganic particles, and using the inorganic particles.

[0029] Even if the resin composition according to this embodiment contains inorganic particles having a low breaking strength in a particle compression test, by satisfying the above-mentioned predetermined requirements, dimensional change when repeatedly heated can be suppressed. That is, when the resin composition according to this embodiment contains inorganic particles having a breaking strength of less than 1080 MPa in a particle compression test, the effect of the present invention is more pronounced. When the resin composition contains inorganic particles having a breaking strength of 1050 MPa or less, the effect of the present invention is even more pronounced. When the resin composition contains inorganic particles having a breaking strength of 1000 MPa or less, the effect of the present invention is even more pronounced. The breaking strength is not particularly limited in terms of its lower limit, but may be, for example, 500 MPa or more.

[0030] The breaking strength of inorganic particles is measured as follows: A compression test of inorganic particles is carried out in accordance with JIS R1639-5, and a plot of strain-strength (MPa) as shown in Figure 1 is obtained. １ The strength of the breaking strength s １ (MPa).

[0031] The resin composition according to the present embodiment can suppress dimensional changes when repeatedly heated by satisfying the above-mentioned predetermined requirements, even if it contains inorganic particles with low absorption energy to break in a particle compression test. That is, when the resin composition according to the present embodiment contains inorganic particles with an absorption energy to break of less than 61.0 MPa in a particle compression test, the effect of the present invention is more pronounced. When the resin composition contains inorganic particles with an absorption energy to break of 55.0 MPa or less, the effect of the present invention is even more pronounced. When the resin composition contains inorganic particles with an absorption energy to break of 50.0 MPa or less, the effect of the present invention is even more pronounced. The absorption energy to break is not particularly limited in terms of its lower limit, but may be, for example, 10.0 MPa or more.

[0032] The absorbed energy until the inorganic particles break is measured as follows. A compression test of the inorganic particles is carried out in accordance with JIS R1639-5, and a plot of displacement (μm) vs. strength (MPa) is obtained as shown in Figure 1. In Figure 1, the plot, the line of strength = 0 MPa, and the line of strain = d １ The area of ​​the region surrounded by the line and the shaded area is calculated as the absorbed energy (MPa) until fracture.

[0033] The resin composition according to this embodiment preferably contains inorganic particles having a ratio of the number of isolated OH groups to the number of hydrogen-bonded OH groups (i.e., "number of isolated OH groups / number of hydrogen-bonded OH groups") of less than 0.39. The smaller the number of isolated OH groups, the weaker the bonding strength between particles, and as a result, particle aggregation and the like can be suppressed. It is more preferable to contain inorganic particles having a ratio of the number of isolated OH groups to the number of hydrogen-bonded OH groups of 0.35 or less, and even more preferable to contain inorganic particles having a ratio of 0.30 or less. On the other hand, it is preferable to contain inorganic particles having a ratio of the number of isolated OH groups to the number of hydrogen-bonded OH groups of 0.01 or more. This facilitates appropriate particle-resin interaction. It is more preferable to contain inorganic particles having a ratio of the number of isolated OH groups to the number of hydrogen-bonded OH groups of 0.03 or more, and even more preferable to contain inorganic particles having a ratio of 0.05 or more. The inorganic particles may have OH groups on their surfaces due to, for example, reaction with moisture in the atmosphere.

[0034] The resin composition according to this embodiment has an isolated OH group count of 3.1 / nm ２ It is preferable that the inorganic particles contain inorganic particles having an isolated OH group number of less than 2.8 / nm. This can prevent aggregation of particles. ２ More preferably, the number of isolated OH groups is 2.5 / nm or less. ２ It is more preferable that the number of isolated OH groups is 2.0 / nm or less. ２ It is more preferable that the number of isolated OH groups is 1.5 / nm or less. ２ On the other hand, it is particularly preferable that the number of isolated OH groups is less than 0.1 / nm ２ It is preferable that the resin contains inorganic particles having an isolated OH group density of 0.2 or more. This facilitates appropriate interaction between the particles and the resin. ２ It is more preferable that the inorganic particles contained therein have a density of 0.3 particles / nm or more. ２ It is more preferable that the inorganic particles contain the above inorganic particles.

[0035] In this embodiment, the number of isolated OH groups and the number of hydrogen-bonded OH groups of inorganic particles can be quantified using the measurement results of the Karl Fischer method (moisture vaporization-titration method) in accordance with the description of JIS K 0068:2001 "Method for measuring moisture content in chemical products." The moisture detected in the Karl Fischer measurement can be considered to be derived from the OH groups of the inorganic particles, and moisture detected at a temperature of 550°C can be considered to be derived from hydrogen-bonded OH groups, while moisture detected at a temperature of 900°C can be considered to be derived from isolated OH groups. Note that the moisture detected in the Karl Fischer measurement is considered to be derived from two OH groups condensing to form one water molecule, and the number of OH groups can be calculated by the following formula (3): Number of OH groups [number / nm ２ ] = 0.0662 × (water content [ppm]) / (specific surface area of ​​inorganic particles [m ２ / g])...(3)

[0036] When quantifying the number of isolated OH groups and the number of hydrogen-bonded OH groups of inorganic particles in a resin composition, first, the resin contained in the resin composition is removed by, for example, dissolving it in an organic solvent, etc., to separate only the inorganic particles. The numbers of isolated OH groups and hydrogen-bonded OH groups can be quantified using the separated inorganic particles in the same manner as described above.

[0037] The resin composition according to this embodiment has a specific surface area of ​​0.20 m ２ It is preferable that the resin contains inorganic particles having a specific surface area of ​​0.36 m / g or more. This facilitates appropriate interaction between the particles and the resin. ２ More preferably, the inorganic particles contained in the coating have a specific surface area of ​​more than 0.40 m / g. ２ It is more preferable that the inorganic particles have a specific surface area of ​​0.45 m / g or more. ２ / g or more, and the specific surface area is 0.55 m ２ It is particularly preferable that the inorganic particles contain inorganic particles having a specific surface area of ​​3.00 m / g or more. ２ / g or less, preferably 2.50m ２ / g or less. In this embodiment, the specific surface area of ​​the inorganic particles is a nitrogen adsorption BET specific surface area, and is measured in accordance with JIS-Z8830 (2013). When the inorganic particles are contained in a resin composition, the resin contained in the resin composition can be removed by, for example, dissolving it in an organic solvent or by heating it to a temperature of 500°C or higher to thermally decompose the resin, and only the inorganic particles can be separated, and the specific surface area can be measured using the inorganic particles.

[0038] By reducing the grain boundary content within the inorganic particles, the shielding effect against alpha rays generated from uranium and thorium within the inorganic particles can be improved, and the amount of alpha rays emitted from the inorganic particles can be reduced. In this embodiment, the ratio of the total length L2 of the grain boundaries to the length L1 of the outer edge (L2 / L1) is introduced as an index of the grain boundary content within the inorganic particles. L1 and L2 are determined by observing the cross section of the inorganic particles.

[0039] When the length of the outer edge of one inorganic particle is L1 and the total length of the grain boundaries of that inorganic particle is L2, inorganic particles with a small L2 / L1 value can be said to have a low grain boundary content and emit a low amount of alpha rays. In particular, it is preferable that (L2 / L1) (%) is less than 139.1%, which can further reduce the amount of alpha rays emitted when used as a filler for a resin composition. By reducing the amount of alpha rays emitted from the inorganic particles, the amount of alpha rays emitted from a resin composition containing the inorganic particles can also be reduced.

[0040] (L2 / L1) is preferably 120.0% or less, more preferably 100.0% or less, even more 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, but may be 10.0% or more, for example, 20.0% or more, 30.0% or more, 40.0% or more, or 43.0% or more. When the lower limit of L2 / L1 is within the above range, particle-resin interactions are more likely to occur, making it easier to increase the mechanical strength, such as the breaking stress, of the resin composition. In order to control this L2 / L1 within a suitable range, single-crystal raw material particles may be used.

[0041] The "total length L2 of the grain boundaries" refers to the sum of the grain boundaries contained within the inorganic particle, not including the outer edge of the inorganic particle. The total length L2 of the grain boundaries is the sum of the total length L3 of the grain boundaries within the inorganic particle and the total length L4 of the inner walls of the cavities (if the inorganic particle has cavities inside) (i.e., L2 = L3 + L4). When the inorganic particles are contained in a resin composition, the resin contained in the resin composition can be removed, for example, by dissolving it in an organic solvent or by heating it to a temperature of 500°C or higher to thermally decompose the resin, and only the inorganic particles can be isolated, and L2 / L1 can be measured using the inorganic particles.

[0042] Inorganic particles with a sharp particle size distribution are preferred because they facilitate appropriate particle-resin interactions. For example, the ratio D90 / D50, the particle diameter D90 (hereinafter sometimes simply referred to as "D90") at 90% cumulative number from the fine particle side of the cumulative particle size distribution to the particle diameter D50 (hereinafter sometimes simply referred to as "D50") at 50% cumulative number from the fine particle side of the cumulative particle size distribution, is preferably 5.0 or less. D90 / D50 is more preferably 4.0 or less, even more preferably 3.0 or less, and particularly preferably 1.5 or less.

[0043] On the other hand, if the particle size distribution of the inorganic particles is broad to some extent, the filling property is improved by allowing small particles to enter the gaps between large particles, and more inorganic particles can be kneaded into the resin, which can improve the dimensional stability and breaking stress against 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.

[0044] The D50 of the inorganic particles is preferably 100 μm or less, more preferably 50 μm or less, even more 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 having D50 within the above range, a resin composition suitable for miniaturizing semiconductor devices and narrowing the wiring pitch can be formed.

[0045] In this embodiment, the D90 and D50 of the inorganic particles can be determined by measuring the particle size distribution of the inorganic particles by laser diffraction using, for example, a laser particle size distribution measuring device such as a "Microtrac MT3300EXII" manufactured by Microtrac-Bell Co., Ltd. The particle size of the inorganic particles in the resin composition can be measured by removing the resin contained in the resin composition by, for example, dissolving it in an organic solvent or by heating it to a temperature of 500°C or higher to pyrolyze the resin, isolating only the inorganic particles, and using the inorganic particles.

[0046] Another method for determining the D90 and D50 of inorganic particles is a method using image analysis. The resin composition may be subjected to cross-sectional observation using an SEM, and all inorganic particles contained in a predetermined observation area (e.g., 200 μm × 200 μm) may be subjected to image analysis, and the particle diameters equivalent to D90 and D50 may be calculated based on the measurement results of their particle diameters (circle-equivalent diameters).

[0047] The inorganic particles preferably have a uranium content of less than 550 ppb and a thorium content of less than 10 ppb. By suppressing the uranium and thorium contents of the inorganic particles to extremely small amounts as described above, the amount of α-rays emitted from the inorganic particles can be reduced, and as a result, the amount of α-rays emitted from the resin composition can be suppressed. This makes it possible to suppress malfunction of the semiconductor device due to α-rays when used as an encapsulating material for a semiconductor device.

[0048] The uranium content is preferably 300 ppb or less, more preferably 100 ppb or less, even more preferably 50 ppb or less, and particularly preferably 30 ppb or less, for example, 10 ppb or less, or 5 ppb or less. The lower limit of the uranium content is not particularly limited, but may be 0.1 ppb or more. The thorium content is preferably 8 ppb or less, more preferably 5 ppb or less, and particularly preferably 2 ppb or less. The lower limit of the thorium content is not particularly limited, but may be 0.1 ppb or more. The uranium content and thorium content can be measured by inductively coupled plasma mass spectrometry (ICP-MS). When inorganic particles are contained in the resin composition, the resin contained in the resin composition can be removed, for example, by dissolving it in an organic solvent or by heating it to a temperature of 500°C or higher to pyrolyze the resin, and only the inorganic particles can be isolated, and the uranium content and thorium content can be measured using the inorganic particles.

[0049] The blending ratio of the inorganic particles, relative to the total resin composition, is preferably 5 to 75 volume% resin, 95 to 25 volume% inorganic particles, or 8 to 50 volume% resin, 92 to 50 volume% inorganic particles, or 10 to 40 volume% resin, 90 to 60 volume% inorganic particles, 12 to 40 volume% resin, and 88 to 60 volume% inorganic particles, in that order. This makes it easier to control the breaking stress and absorbed energy to break of the resin composition to the desired values. Furthermore, in the semi-cured and cured resin compositions, the total proportion of resin and inorganic particles relative to the total resin composition is preferably 60 volume% or more, more preferably 70 volume% or more, and even more preferably 80 volume% or more. Furthermore, in the semi-cured and cured resin compositions, the proportion of solids relative to the total resin composition is preferably 80 volume% or more, more preferably 90 volume% or more, and even more preferably 95 volume% or more. The solid content of a resin composition refers to what remains as a solid when the resin composition is heated, excluding components that volatilize upon heating, such as the solvent. On the other hand, even if a component is liquid at 25°C, if it is incorporated into the solid content of the resin composition when heated, it is included in the solid content. The proportion of solids can be determined, for example, by determining the amount of solvent in the resin composition and subtracting it from the total. The amount of solvent in a resin composition can be measured, for example, by the following method. After measuring the mass W1 (g) of the resin composition, a sample is heated at 150°C for 10 minutes using a full exhaust oven to evaporate all of the solvent contained in the sample, and then 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. The amount of solvent in the resin composition can be determined by subtracting W2 (g) from W1 (g).

[0050] The resin composition of the present invention exhibits little dimensional change when repeatedly heated and has excellent dimensional stability. In the present invention, the dimensional stability can be evaluated by measuring the CTE twice and then calculating the CTE change rate from the following formula (4). The CTE change rate is preferably less than 8.5, more preferably 8.4 or less, even more preferably 8.0 or less, still more preferably 7.0 or less, and particularly preferably 6.0 or less. CTE change rate (%) = (CTE at first measurement - CTE at second measurement) / (CTE at first measurement) × 100 (4)

[0051] The resin used in the resin composition preferably includes one or more resins selected from the group consisting of epoxy resins and thermoplastic polyimides, and more preferably includes an epoxy resin. Preferred epoxy resins include mesogenic epoxy resins, phenylcyclohexyl epoxy resins, naphthalene epoxy resins, phenolic epoxy resins, biphenyl epoxy resins, butadiene epoxy resins, and bisphenol A epoxy resins. Mesogenic epoxy resins are epoxy resins having mesogenic groups, and are preferably resins that exhibit a phase transition temperature in the temperature range of 100°C to 200°C and exhibit liquid crystallinity. The resin composition may also include one or more epoxy resins. That is, the resin composition may include one or more epoxy resins selected from the group consisting of mesogenic epoxy resins, phenylcyclohexyl epoxy resins, naphthalene epoxy resins, phenolic epoxy resins, biphenyl epoxy resins, butadiene epoxy resins, and bisphenol A epoxy resins, and may further include a thermoplastic polyimide. These resins are expected to have the effect of shielding alpha rays that may be emitted from inorganic particles. Furthermore, by using these resins, it becomes easier to obtain a resin composition that has high dimensional stability against external energy such as heat.

[0052] Furthermore, these resin compositions may contain known additives, such as plasticizers, curing agents, curing accelerators, coupling agents, fillers, pigments, flame retardants, antioxidants, surfactants, compatibilizers, weathering agents, antiblocking agents, antistatic agents, leveling agents, and mold release agents, either singly or in combination, as long as the effects of the invention are not impaired. In one embodiment of the present application, the resin composition (particularly a liquid or semi-cured resin composition) may contain a solvent. When the resin composition contains a solvent, it is highly fluid, can be easily deformed to fit the fine structures of IC chips and substrates, and can seal dense structures without gaps. Known solvents can be used as long as they can dissolve the resin, but 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. Ketone-based solvents and ester-based solvents are preferred because they are good solvents for epoxy resins and provide excellent coatability for the resulting resin composition.

[0053] In a preferred embodiment of the present invention, the resin composition comprises inorganic particles, an epoxy resin, a solvent, and a curing agent, such as an amine-based curing agent such as 4,4-diaminodiphenylmethane.

[0054] A method for producing a resin composition will be described. A resin composition can be obtained by mixing inorganic particles and a resin using a commonly used known method. For example, when the resin is liquid (e.g., liquid epoxy resin), the resin composition can be obtained by mixing the liquid resin, inorganic particles, and a curing agent and then curing with heat or ultraviolet light. Known curing agents, mixing methods, and curing methods can be used. On the other hand, when the resin is solid (e.g., epoxy resin, polyolefin resin, acrylic resin, etc.), the inorganic particles and the resin can be mixed and then kneaded by a known method such as melt kneading, or the resin, inorganic particles, and curing agent can be dissolved and mixed in a solvent to obtain the desired resin composition. The resin composition may contain a solvent.

[0055] The resin composition according to this embodiment includes resin compositions in all states, including a liquid state before the resin in the resin composition is cured, a semi-cured state (B stage) in which the resin is semi-cured, and a cured state (C stage) in which the resin is completely cured. Liquid resin compositions include blends in which alumina powder and resin are blended in a predetermined ratio, mixtures obtained by mixing such blends, and molded articles obtained by molding such mixtures. Semi-cured resin compositions include resin compositions obtained by semi-curing the resin contained in the mixture or molded article. Cured resin compositions include resin compositions obtained by completely curing the resin contained in the mixture, molded article, or semi-cured article.

[0056] The method for producing inorganic particles according to this embodiment will be described by taking a method for producing alumina particles as an example.

[0057] First, alumina as a raw material is produced by a known method, such as the Bayer method, the ammonium alum method, the ammonium aluminum carbonate hydroxide method (AACH method), the solvent extraction method, the organoaluminum hydrolysis method (aluminum alkoxide method), or a melt growth method such as the CZ method, the Verneuil method, the chiroporous method, the Bridgman method, or the EFG method.

[0058] In the case of the Bayer process, raw alumina can be produced by calcining aluminum hydroxide obtained from bauxite. Furthermore, the ammonium alum process, the AACH process, the solvent extraction process, and the aluminum alkoxide process are preferred because they allow for the production of high-purity raw alumina with low uranium and thorium contents. Raw alumina produced by these processes, with a uranium content of less than 550 ppb and a thorium content of less than 10 ppb by mass, respectively, can be used to produce alumina particles, which are preferred because they allow for the production of alumina particles with low uranium and thorium contents.

[0059] In order to easily obtain alumina particles of a desired size by flame melting, the raw alumina is pulverized to obtain an alumina raw powder to be subjected to flame melting. The pulverization of the raw alumina can be carried out by a known method such as a vibration mill, a bead mill, a ball mill, or a jet mill, and may be carried out in either a dry or wet state.

[0060] A surface protective agent may be used in the above-described pulverization. The surface protective agent not only protects the surface of the alumina raw material powder after pulverization but may also have the function of inactivating the surface of the alumina raw material powder. The surface inactivation function of the surface protective agent can reduce aggregation of the alumina raw material powder. Therefore, the surface protective agent is suitable for obtaining alumina particles of a desired particle size after flame fusion using raw alumina with a high BET specific surface area, which is prone to aggregation. Suitable surface protective agents include, for example, monohydric alcohols such as methanol, ethanol, 1-propanol, and 2-propanol; glycols 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 protective agents may be used alone, or two or more may be used in combination. Among these, glycols are preferred, and one or more of ethylene glycol, polyethylene glycol, propylene glycol, and polypropylene glycol are particularly preferred.

[0061] The molecular weight of the polyethylene glycol and polypropylene glycol preferably used as the surface protective agent is not particularly limited, but liquids with an average molecular weight of about 200 to 600 are preferred for ease of addition.

[0062] The amount of the surface protective agent added is preferably 0.01 parts by mass or more relative to 100 parts by mass of raw alumina in order to fully exert the effect of the surface protective agent, and is preferably 10 parts by mass or less because the effect of the surface protective agent becomes saturated if the amount of the surface protective agent added is too large. The amount of the surface protective agent added is more preferably 0.05 to 8 parts by mass, and even more preferably 0.1 to 5 parts by mass.

[0063] Here, the flame fusion method will be described. The flame fusion method is a method in which the raw material of inorganic particles (raw alumina in the case of alumina particles) is sprayed into a flame, turned into droplets, and then cooled and solidified. By using the flame fusion method, inorganic particles can be obtained while roughly maintaining the particle size of the inorganic particle raw material. In the flame fusion method, the temperature of the flame fusion furnace is preferably 1000°C or higher. In particular, in the flame fusion method, by setting the raw material supply rate to 50 kg / h or less, preferably 10 kg / h or less, it becomes easier to suppress aggregation between particles and the like, and it also becomes easier to promote appropriate interaction between the particles and the resin, resulting in a resin composition that satisfies the above-mentioned specified requirements being more easily obtained.

[0064] After the flame fusion, the alumina particles are collected by a cyclone and / or a bag filter and classified to obtain alumina particles having desired properties.

[0065] The number of isolated OH groups in the alumina particles can be controlled by the conditions of the manufacturing method, pulverization method, and flame fusion method of the raw alumina, but can also be controlled by immersing the obtained alumina particles in an acidic solution such as hydrochloric acid. The type of acidic solution used during immersion is preferably hydrochloric acid because of its ease of concentration adjustment. The concentration of the acidic solution is preferably adjusted to 1 M to 12 M, more preferably 1 M to 10 M, and particularly preferably 2 M to 5 M. The mass ratio during immersion, i.e., alumina particles to acidic solution, is preferably 1:2 to 1:10. The immersion time is preferably 5 hours or longer. During immersion, heating may be performed as appropriate to shorten the immersion time, for example, heating to 50 to 90°C. After immersion, washing and drying are preferably performed.

[0066] [Sheet Molding Compound (SMC)] A sheet molding compound (SMC) can be provided using the resin composition according to the embodiment. The SMC is a resin composition molded into a sheet. The SMC preferably has fluidity when heated and pressurized, and may be in a semi-cured state. The SMC preferably has a thickness of 1000 μm or less. When incorporated into a semiconductor device, the semiconductor device can be made smaller and lighter, and the sealing performance can be improved when sealing an IC chip. The thickness is more preferably 800 μm or less, even more preferably 600 μm, even more preferably 500 μm or less, particularly preferably 400 μm or less, and particularly preferably 300 μm or less. The lower limit of the thickness is not particularly limited, but may be, for example, 10 μm or more, 50 μm or more, or even 100 μm or more, or 150 μm or more, depending on the dimensions of commonly used SMCs and the ability to enhance the sealing performance of IC chips.

[0067] SMCs can be produced by known methods. For example, an uncured resin composition is applied to a substrate, a protective film is placed thereon, and the resin composition is semi-cured. Another example is a solvent-containing uncured resin composition applied to a substrate, the solvent is removed from the resin composition by drying, or the like, and then a protective film is placed thereon. When using an SMC, the protective film is peeled off, the SMC is pressure-bonded to a wafer or the like, the substrate is removed, and the SMC is post-cured.

[0068] The resin composition and SMC according to this embodiment can suppress dimensional changes when repeatedly heated, and are therefore suitable as sealing members for semiconductor elements.

[0069] [Preparation of Inorganic Particles] The inorganic particles (A to C) used in the resin compositions of Samples No. 1 to 4 were prepared as follows.

[0070] (Inorganic Particles A and B Used in Samples Nos. 1 to 3) The following inorganic particles A (alumina particles, used in Sample No. 3) and inorganic particles B (alumina particles, used in Samples Nos. 1 and 2) were prepared as inorganic particles.

[0071] As a raw material for inorganic particles, γ-alumina (the average particle size of the primary particles calculated from the value of the BET specific surface area below is 13 nm) obtained by the ammonium alum method was used. The BET specific surface area of ​​this γ-alumina measured by the nitrogen adsorption method was 120 m ２ Before pulverization, 4 mass % of propylene glycol was added as a surface protective agent to the raw alumina and mixed.

[0072] Next, the mixture was treated using a jet mill pulverizer (horizontal jet mill pulverizer PJM-280SP manufactured by Nippon Pneumatic Mfg. Co., Ltd.) under the conditions of a raw material alumina feed rate of 30 kg / h and a gauge pressure at the air supply port during pulverization of 0.5 MPa, to obtain an alumina raw material powder having an average particle size of secondary particles of about 2 μm.

[0073] The resulting alumina raw material powder was charged into a flame fusion furnace and melted to obtain spherical alumina particles. The atmospheric temperature in the flame fusion furnace was set to 1250°C, and the raw material feed rate was set to 5 kg / h. The resulting alumina particles were collected using a cyclone and classified by cyclone classification to remove particles of 20 μm or larger, thereby obtaining inorganic particles A (D50 = 5.1 μm, used in Sample No. 3). Furthermore, particles of 10 μm or larger were removed to obtain inorganic particles B (D50 = 2.3 μm, used in Samples No. 1 and 2).

[0074] (Alumina particles C used in sample No. 4) For sample No. 4, alumina particles (inorganic particles C) manufactured by Denka DAW05 were used.

[0075] The inorganic particles used in each sample were subjected to the following measurements.

[0076] [Strain at fracture of inorganic particles] A compression test of inorganic particles was conducted in accordance with JIS R1639-5, and a plot of displacement vs. test force was obtained. The displacement of the plot was converted to strain based on the following formula (1), and the test force of the plot was converted to strength based on the following formula (2), to obtain a plot of strain vs. strength. Strain = Displacement [m] / D [m] (1) Strength [MPa] = 2.48 × Test force [N] / (π × D ２) (2) where D [m] is the average value of the major and minor diameters of the inorganic particles to be tested. The major and minor diameters were measured by observation with an optical microscope. When there is one region where the slope is constant in the strain-strength plot, the minimum displacement where the displacement exceeds 0 and the slope is constant is defined as the breaking point P １ and the breaking point P １ Distortion d in １ is the strain at the time of fracture in the compression test of the particle. When there are multiple regions with a constant slope, the starting point of the region where the difference in strain between the end point and the starting point of the region is the largest is taken as the fracture point P １ It was decided.

[0077] [Breaking strength of inorganic particles] In the strain-strength plot, the breaking point P １ The strength of the inorganic particles is １ (MPa).

[0078] [Absorbed energy until destruction of inorganic particles] In the above strain-strength plot, the plot, the line of strength = 0 MPa, and the line of strain = d １ The area of ​​the region surrounded by the line and the shaded area was calculated as the absorbed energy (MPa) until the inorganic particles were broken.

[0079] [Number of Isolated OH Groups and Number of Hydrogen-Bonded OH Groups of Inorganic Particles] The number of isolated OH groups and the number of hydrogen-bonded OH groups of inorganic particles were quantified using the measurement results of the Karl Fischer method (moisture vaporization-titration method) in accordance with the description of JIS K 0068:2001 "Method for measuring moisture content in chemical products." The moisture detected in the Karl Fischer measurement was considered to be derived from the OH groups of the inorganic particles, and moisture detected at a temperature of 550°C was considered to be derived from hydrogen-bonded OH groups, while moisture detected at a temperature of 900°C was considered to be derived from isolated OH groups. Note that the moisture detected in the Karl Fischer measurement is considered to be derived from two OH groups condensing to form one water molecule, and the number of OH groups was calculated using the following formula (3): Number of OH groups [number / nm ２ ] = 0.0662 × (water content [ppm]) / (specific surface area of ​​inorganic particles [m ２ / g])...(3)

[0080] [Particle size distribution of inorganic particles] The particle size distribution of inorganic particles (alumina particles) was measured by laser diffraction using a Microtrac MT3300EXII laser particle size distribution analyzer manufactured by Microtrac Bell Co., Ltd. The D50 and D90 were determined from the particle size distribution measurement results. The measurement sample was an inorganic particle dispersion obtained by adding the inorganic particles to be measured to a 0.2% by mass aqueous solution of sodium hexametaphosphate so that the laser scattering intensity was appropriate, and dispersing the inorganic particles for 5 minutes using the built-in ultrasonic wave at 40 W. The refractive index of the inorganic particles (alumina) was set to 1.76.

[0081] [BET Specific Surface Area of ​​Inorganic Particles] A Shimadzu Flowsorb III 2310 specific surface area measuring device was used, and the nitrogen adsorption BET specific surface area was determined by the single-point nitrogen adsorption method in accordance with the method specified in JIS-Z8830 (2013). The measurement conditions were as follows: Carrier gas: nitrogen / helium mixed gas; Sample amount: 0.1 g; Sample pretreatment conditions: 20 minutes at 200°C; Nitrogen adsorption temperature: liquid nitrogen temperature (-196°C or lower); Nitrogen desorption temperature: room temperature (approximately 20°C).

[0082] [Measurement of the length L1 of the outer edge of an inorganic particle and the total length L2 of the grain boundary inside the particle] Samples for cross-sectional observation were prepared using inorganic particles (alumina particles) of Samples No. 1 to 4. To prepare the cross-sectional observation samples, the inorganic particles were embedded in a resin for cross-sectional observation, and then the resin and inorganic particles were cut using a diamond cutter. Subsequently, Pt was vapor-deposited onto the cross-section as a protective film, and the cross-section was prepared by Ar ion milling. The sample was then fixed to the SEM sample stage with Cu double-sided tape, and SEM-EBSD measurement was performed without vapor deposition. The observation position was determined so that two or more inorganic particles were completely contained within the observation area (i.e., two or more inorganic particles did not come into contact with the frame of the observation area). All of the inorganic particles measured were α-alumina particles.

[0083] The following equipment was used for sample pretreatment and EBSD measurement: Equipment used Ion milling equipment: IM-4000 (manufactured by Hitachi, Ltd.) Ion sputtering equipment: E-1030 (manufactured by Hitachi, Ltd.) Ultra-high resolution field emission scanning electron microscope: JSM-7800F Prime (manufactured by JEOL Ltd.) Backscattered electron diffraction equipment: Digiview V (manufactured by TSL)

[0084] The conditions for the EBSD measurement were as follows: Measurement area: 500.0 μm×400.0 μm Acceleration voltage: 20.0 kV Magnification: ×500 Vacuum degree: 30 Pa

[0085] In the obtained EBSD image, two or more inorganic particles that were not in contact with the frame of the observation area were selected, and the average of the outer edge length L1 of each inorganic particle was calculated using image processing software Image J (manufactured by the National Institute of Health). The "total length L2 of grain boundaries" is the sum of the grain boundaries contained inside the inorganic particle, and does not include the outer edge of the inorganic particle. The total length L2 of grain boundaries was calculated by adding the total length of the grain boundaries inside the inorganic particle and the total length of the inner wall of the cavity (if there is a cavity inside the inorganic particle).

[0086] The ratio of the total length L2 of the grain boundaries to the length L1 of the outer edge (L2 / L1) was expressed as a percentage (%). The more grain boundaries and voids there are inside the inorganic particles, the larger the value of L2 / L1 (%).

[0087] [Uranium and Thorium Contents of Inorganic Particles] The uranium content (U amount) and thorium content (Th amount) contained in inorganic particles (alumina particles) were measured as follows. First, the inorganic particles were placed in a mixed aqueous solution of sulfuric acid and phosphoric acid, and heated to dissolve the inorganic particles, preparing an aqueous solution. Then, this aqueous solution was contacted with a cyclohexane solution of tributyl phosphate, which is commonly used as an extractant for uranium, to extract the uranium contained in the aqueous solution. Then, the uranium was transferred to the aqueous phase by back-extraction, which involved contacting the particles with pure water again, and the uranium was measured using ICP-MS based on the intensities of U 238 amu and Th 232 amu. Note that a standard solution manufactured by SPEX was used to create a calibration curve.

[0088] [α-ray dose emitted from inorganic particles] The α-ray dose emitted from inorganic particles (alumina particles) was measured using a measuring device Model 1950 (manufactured by Alpha Sciences). The measurement area of ​​the sample was 1000 cm ２ The measurement time was 99 hours, and the counting gas was PR-10 gas (Ar 90%, CH ４ 10%) was used.

[0089] [Preparation of Resin Composition] Resin compositions were prepared by kneading inorganic particles (alumina particles), resin, etc. (Samples No. 1 to 4). The types of resin used are shown in Table 1, and the blending (addition) amounts of inorganic particles are shown in Table 3. The elastic modulus of the resin not containing inorganic particles when cured was measured, and this is shown in the "Elastic Modulus" column of "Resin" in Table 3. The resin compositions of Samples No. 1 to 4 were specifically prepared according to the following preparation method. The "Resin Composition" shown in Table 3 refers to the resin composition in a cured state.

[0090] (1) Preparation of Varnish A 30% by mass mixed solution was prepared by dissolving the resin shown in Table 1 in the solvent shown in Table 1. Furthermore, a curing agent (4,4-diaminodiphenylmethane (manufactured by TCI)) was added in an amount of 0.074% by mass relative to 100% by mass of the mixed solution to prepare a varnish.

[0091] (2) Preparation of Inorganic Particle / Varnish Mixture Inorganic particles were added to the obtained varnish, and the mixture was kneaded using a planetary centrifugal mixer (manufactured by Thinky Corporation) to prepare an inorganic particle / varnish mixture.

[0092] (3) Film Formation The obtained inorganic particle / varnish mixture was applied to a PET substrate, and a film was formed using an applicator so that the film thickness after thermal curing would be 150 to 200 μm, thereby obtaining a resin composition before curing.

[0093] (4) Thermal Curing The obtained uncured resin composition was allowed to stand at room temperature for 1 hour, then heated at 140°C for 15 minutes, and then vacuum press molded at 140°C for 20 minutes at a pressure of 0.5 MPa using a press molding machine. The composition was then heated at 180°C for 120 minutes at normal pressure to thermally cure. This resulted in cured resin compositions (Samples No. 1 to 4). The resin compositions of Samples No. 1 to 4 had a solids content of 95% or more by volume relative to the total resin composition.

[0094]

[0095] Details of the types of resins listed in Table 1 are as follows:

[0096] Mesogenic epoxy resin (A) is a prepolymer obtained by reacting trans-4-{4-(2,3-epoxypropoxy)phenyl}cyclohexyl 4-(2,3-epoxypropoxy)benzoate (an epoxy resin represented by the structural formula below) with 6-hydroxy-2-naphthoic acid.

[0097]

[0098] Mixture of JP-100 and HP6000 This mixture was prepared by mixing JP-100 (manufactured by Nippon Soda), an epoxidized polybutadiene, and HP-6000 (manufactured by DIC), a naphthalene-based epoxy resin, in a mass ratio of 1:9.

[0099] [Stress at break, absorbed energy to break, correlation coefficient of stress-strain curve to break, and elastic modulus of resin composition] The stress at break, absorbed energy to break, correlation coefficient of stress-strain curve to break, and elastic modulus of resin composition were measured in accordance with JIS K7161 (2014). Specifically, a tensile test was performed under the following conditions, and the obtained stress-strain curve was analyzed and calculated. Testing equipment: Autograph AGS-X (manufactured by Shimadzu Corporation) Load cell: 1 kN Test piece dimensions: 100 mm x 10 mm Testing environment: 22°C / 59% RH Analysis software: TRAPEZIUMX

[0100] [α-ray Dose Emitted from Resin Composition] The α-ray dose emitted from the resin composition was measured using a measuring device Model 1950 (manufactured by Alpha Sciences). The measurement area of ​​the sample was 1000 cm ２ The measurement time was 99 hours, and the counting gas was PR-10 gas (Ar 90%, CH ４ 10%) was used.

[0101] [Dimensional Change of Resin Composition When Repeatedly Heated] The dimensional change of the resin composition when repeatedly heated was evaluated as follows. First, the coefficient of thermal expansion (CTE) in the temperature range of 27°C to 150°C was determined by thermomechanical analysis in accordance with JIS K7197. The analysis conditions are as follows: Apparatus: TMA7100 (manufactured by Hitachi High-Tech Science) Measurement mode: Tensile mode Test piece width: 5 mm Chuck distance: 20 mm Temperature increase / decrease process: The temperature was increased from 20°C to 200°C at a rate of 5°C / min, and then cooled from 200°C to 20°C at a rate of 5°C / min. CTE calculation temperature range: 27°C to 150°C during the temperature increase process Measurement load: 0.05 N The above CTE measurement was performed twice, and the smaller the CTE change rate calculated from the following formula, the smaller the dimensional change when repeatedly heated. CTE change rate (%)=(CTE at first measurement−CTE at second measurement) / (CTE at first measurement)×100

[0102] Table 2 shows the results of various measurements of the inorganic particles, and Table 3 shows the types (and elastic moduli) of the resins used and the results of various measurements of the resin compositions.

[0103]

[0104]

[0105] The measurement results are discussed below. The resin compositions of Samples 1 to 3, which met the requirements of this embodiment, were able to sufficiently suppress dimensional change when repeatedly heated (i.e., the CTE change rate was 8.4% or less). On the other hand, the resin composition of Sample 4, which did not meet the requirements of this embodiment, had a CTE change rate of 8.5%, and was unable to sufficiently suppress dimensional change when repeatedly heated.

Claims

1. A resin composition comprising inorganic particles and a resin, having a breaking stress of more than 41.2 MPa, and an absorbed energy to break of more than 0.314 MPa.

2. The resin composition according to claim 1, wherein the correlation coefficient when the stress-strain curve up to break is linearly approximated exceeds 0.9765.

3. The resin composition according to claim 1, having an alpha radiation dose of less than 0.022 cph / cm2.

4. The resin composition according to claim 1, wherein the inorganic particles have a strain at break of less than 0.113 in a particle compression test.

5. The resin composition according to claim 1, wherein the inorganic particles have a breaking strength of less than 1080 MPa in a particle compression test.

6. The resin composition according to claim 1, wherein the inorganic particles have an absorbed energy of less than 61.0 MPa until breaking in a particle compression test.

7. The resin composition according to claim 1, wherein the inorganic particles have a ratio of the number of isolated OH groups to the number of hydrogen-bonded OH groups of less than 0.

39.

8. The resin composition according to claim 1, wherein the inorganic particles have a number of isolated OH groups of less than 3.1 / nm2.

9. A sheet molding compound comprising the resin composition according to any one of claims 1 to 8 and having a thickness of 1000 μm or less.

Images