Sealing resin composition, semiconductor device, and manufacturing method of semiconductor device

Abstract

To provide a sealing resin composition capable of ensuring connectivity between a substrate and a semiconductor chip while being less likely to produce voids even when the mounting time of the semiconductor chip on the substrate is shortened.SOLUTION: The sealing resin composition is used for sealing a gap between a substrate 2 and a semiconductor chip 3 mounted on the substrate 2. The sealing resin composition contains a radical polymerizable monomer (A) and a thermoplastic elastomer (B). The mass ratio of the thermoplastic elastomer (B) to the total amount of the sealing resin composition is 3 mass % or more and 19 mass % or less. The sealing resin composition has a minimum melt viscosity of 500 Pa s or more and 5000 Pa s or less at temperatures between 60°C and 180°C.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an encapsulating resin composition, a semiconductor device, and a method for manufacturing the semiconductor device. More specifically, the present disclosure relates to an encapsulating resin composition used to seal a gap between a substrate and a semiconductor chip, a semiconductor device including an encapsulant made from the encapsulating resin composition, and a method for manufacturing the semiconductor device. [Background technology]

[0002] Patent Document 1 discloses a semiconductor device in which a semiconductor chip and a substrate are bonded together using a film adhesive. It is disclosed that this film adhesive has a low melt viscosity, which allows for lower chip mounting temperatures and compatibility with flip-chip connection methods. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-042754 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the inventor's research, when mounting a semiconductor chip using a film adhesive, if mounting is attempted in a short time to improve manufacturing efficiency, etc., it is found that there is a tendency for unfilled space to occur under the semiconductor chip, which in turn deteriorates the connectivity between the substrate and the semiconductor chip, and can cause poor conductivity in the semiconductor device. It has also been found that in this case, there is a problem that voids are likely to remain in the sealing material between the substrate and the semiconductor chip.

[0005] An object of the present disclosure is to provide an encapsulating resin composition that can ensure connectivity between a substrate and a semiconductor chip even when the mounting time of the semiconductor chip on the substrate is shortened and that is less likely to produce voids, a semiconductor device including an encapsulant made of a cured product of this encapsulating resin composition, and a method for manufacturing a semiconductor device. [Means for solving the problem]

[0006] An encapsulating resin composition according to one embodiment of the present disclosure is used to seal a gap between a substrate and a semiconductor chip mounted on the substrate. The encapsulating resin composition contains a radically polymerizable monomer (A) and a thermoplastic elastomer (B). The mass ratio of the thermoplastic elastomer (B) to the total amount of the encapsulating resin composition is 3 mass% or more and 19 mass% or less. The encapsulating resin composition has a minimum melt viscosity of 500 Pa·s or more and 5000 Pa·s or less at 60°C or more and 180°C or less.

[0007] A semiconductor device according to one aspect of the present disclosure includes a substrate, a semiconductor chip mounted face-down on the substrate, and an encapsulant that seals a gap between the substrate and the semiconductor chip, the encapsulant comprising a cured product of the encapsulating resin composition.

[0008] A method for manufacturing a semiconductor device according to one aspect of the present disclosure is a method for manufacturing a semiconductor device including a substrate, a semiconductor chip mounted on the substrate, and an encapsulant that seals a gap between the substrate and the semiconductor chip. The sealing of the gap between the substrate and the semiconductor chip includes applying ultrasonic vibration to the solder bumps while heating the solder bumps and the encapsulating resin composition, with the solder bumps and the encapsulating resin composition interposed between the substrate and the semiconductor chip. [Effects of the Invention]

[0009] According to the present disclosure, even if the time required to mount a semiconductor chip on a substrate is shortened, high connectivity between the substrate and the semiconductor chip can be achieved and voids are less likely to occur. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1A is a schematic cross-sectional view showing a semiconductor device according to one embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view showing a semiconductor device according to another embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a laminate sheet according to one embodiment of the present invention. [Figure 3] 3A to 3D are schematic cross-sectional views illustrating steps of mounting a semiconductor chip on a substrate in one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1. Overview The background to the invention of the present disclosure will be explained.

[0012] The inventors have been researching encapsulants for sealing the gap between the substrate 2 and the semiconductor chip 3 in the semiconductor device 1, and have found that when an encapsulating resin composition is interposed between the substrate 2 and the semiconductor chip 3 to seal the gap, if the encapsulating resin composition is insufficiently filled, it becomes difficult to ensure connectivity between the substrate 2 and the semiconductor chip 3. Furthermore, when an encapsulating resin composition (e.g., a sheet material) is interposed between the substrate 2 and the semiconductor chip 3 to seal the gap, the viscosity of the encapsulating resin composition when melted can easily cause insufficient filling between the substrate 2 and the semiconductor chip 3, and voids can easily occur under the semiconductor chip 3. The inventors have found that the above problems are particularly likely to occur when the semiconductor chip 3 is mounted on the substrate 2 in a short period of time.

[0013] Therefore, the inventors have conducted extensive research to solve the above problems and have completed the invention of the encapsulating resin composition of the present disclosure.

[0014] That is, the encapsulating resin composition according to one embodiment of the present invention is used to seal the gap between the substrate 2 and the semiconductor chip 3 mounted on the substrate 2. The encapsulating resin composition contains a radically polymerizable monomer (A) and a thermoplastic elastomer (B). The proportion of the thermoplastic elastomer (B) relative to the total amount of the encapsulating resin composition is 3% by mass or more and 19% by mass or less. The encapsulating resin composition has a minimum melt viscosity of 500 Pa·s or more and 5000 Pa·s or less at 60°C or more and 180°C or less. As a result, even when the encapsulating resin composition is interposed in the gap between the substrate 2 and the semiconductor chip 3 for encapsulation, the gap between the substrate 2 and the semiconductor chip 3 can be reinforced, achieving high connectivity and reducing the likelihood of voids under the semiconductor chip 3. Therefore, according to one embodiment of the present invention, the reliability of the semiconductor device 1 can be improved, including the encapsulant 4 made from the encapsulating resin composition between the substrate 2 and the semiconductor chip 3.

[0015] The reason why the encapsulating resin composition according to one embodiment of the present invention has the above-described effects is not clearly understood, but is presumed to be due to the following reasons.

[0016] The inclusion of the radically polymerizable monomer (A) in the encapsulating resin composition provides the encapsulating resin composition with appropriate curability, while the inclusion of the thermoplastic elastomer (B) in a range of 3% by mass to 19% by mass provides the encapsulating resin composition with good fluidity. Although the thermoplastic elastomer (B) softens due to the heat applied during mounting, the content within the above range prevents the viscosity of the encapsulating resin composition from being excessively low, maintaining a suitable viscosity during heat melting, thereby ensuring the fluidity of the encapsulating resin composition. This is believed to reduce the risk of gaps between the substrate 2 and the semiconductor chip 3 being left unfilled, thereby improving the connectivity between the substrate 2 and the semiconductor chip 3. Furthermore, the inclusion of the thermoplastic elastomer (B) and the encapsulating resin composition with a minimum melt viscosity of 500 Pa·s to 5000 Pa·s at 60°C to 180°C reduces the likelihood of components that could cause voids, such as bubbles, remaining in the encapsulating resin composition during heat melting. Furthermore, in this embodiment, when the encapsulating resin composition is heated, melted, and flowed, the flow pressure of the encapsulating resin composition is improved, and even if bubbles that may cause voids are generated in the encapsulating resin composition, the bubbles are easily broken. This is thought to make it more difficult for voids to be generated in the encapsulating material produced from the encapsulating resin composition.

[0017] In this way, the encapsulating resin composition of this embodiment is used to seal the gap between the substrate 2 and the semiconductor chip 3, and can reinforce the gap between the substrate 2 and the semiconductor chip 3, sufficiently ensure electrical continuity between the substrate 2 and the semiconductor chip 3, and achieve good connectivity. In particular, the encapsulating resin composition of this embodiment is suitable for use when solder bumps 32 and the encapsulating resin composition are interposed between the substrate 2 and the semiconductor chip 3, and then the solder bumps 32 and the encapsulating resin composition are bonded by applying ultrasonic vibrations to the solder bumps 32 while heating them, i.e., when so-called ultrasonic mounting is performed.

[0018] When ultrasonic mounting is performed, the use of ultrasonic vibrations in combination shortens the heating time while achieving electrical connection between the substrate 2 and the semiconductor chip 3 via the solder bumps 32. Even with a relatively short heating time, the encapsulating resin composition is sufficiently cured and easily fills the entire gap between the substrate 2 and the semiconductor chip 3. This allows the encapsulating material 4 to reinforce the bond between the substrate 2 and the semiconductor chip 3. This facilitates sufficient flow of the encapsulating resin composition during ultrasonic mounting, thereby facilitating electrical connection between the substrate 2 and the semiconductor chip 3 via the solder bumps 32 and reducing the likelihood of unfilled portions of the encapsulating material 4. Furthermore, as described above, the encapsulating resin composition of this embodiment is less likely to produce voids under the semiconductor chip 3. This allows the semiconductor chip 3 to be efficiently mounted to the substrate 2 by ultrasonic mounting while ensuring the reliability of the semiconductor device 1.

[0019] In the present disclosure, the term "relatively short time" means a time that is shorter than the time normally required to flip-chip mount a semiconductor chip onto a substrate by thermocompression bonding or the like, and specifically, for example, a time of 1 second or more and 5 seconds or less, although the time is not limited to the above range.

[0020] 2.Details The encapsulating resin composition according to this embodiment will be described below.

[0021] [Sealing resin composition] As described above, the encapsulating resin composition is used to seal the gap between the base material 2 and the semiconductor chip 3 mounted on the base material 2.

[0022] To form the encapsulating material 4 from the encapsulating resin composition, for example, solder bumps 32 and the encapsulating resin composition are interposed between the substrate 2 and the semiconductor chip 3, and the encapsulating resin composition and solder bumps 32 are heated and ultrasonic vibrations are applied while the encapsulating resin composition and solder bumps 32 are interposed between the substrate 2 and the semiconductor chip 3 (see FIGS. 3A and 3B). The encapsulating resin composition melts and flows when heated, and the conductor wiring 21 of the substrate 2 and the bump electrodes 31 of the semiconductor chip 3 are bonded via the solder bumps 32 by ultrasonic vibrations (see FIGS. 3C and 3D). The encapsulating resin composition is then further heated to harden it. In this way, the encapsulating material 4 is produced from the encapsulating resin composition (see FIG. 1).

[0023] The encapsulating resin composition of the present embodiment can make voids less likely to occur in the encapsulating material 4, and can easily ensure high connectivity between the substrate 2 and the semiconductor chip 3. Therefore, when the semiconductor chip 3 is flip-chip mounted on the substrate 2, voids are less likely to occur in the encapsulating material 4 even when ultrasonic mounting is performed, and therefore, when an encapsulating material is produced using the encapsulating resin composition, the reliability of the semiconductor device 1 can be ensured.

[0024] In this way, the encapsulating resin composition can be suitably used as an encapsulating material for producing the encapsulating material 4 that seals between a substrate 2 having conductor wiring 21 and a semiconductor chip 3 having bump electrodes 31, particularly when the encapsulating resin composition is heated and ultrasonic vibrations are applied to melt the encapsulating resin composition and electrically connect the conductor wiring 21 and the bump electrodes 31.

[0025] In this embodiment, as described above, the minimum melt viscosity of the encapsulating resin composition at 60°C or higher and 180°C or lower is 500 Pa·s or higher and 5000 Pa·s or lower. The minimum melt viscosity of the encapsulating resin composition is preferably 800 Pa·s or higher. This minimum melt viscosity is preferably 4500 Pa·s or lower. In this case, when preparing the encapsulating material 4 from the encapsulating resin composition, the fluidity of the encapsulating resin composition can be improved when heated and molded. Furthermore, in this case, even if bubbles or the like are generated in the encapsulating resin composition when mounting the semiconductor chip 3 on the substrate 2 in a short time, they can be easily expelled. Therefore, voids can be further reduced in the encapsulating material 4 prepared from the encapsulating resin composition, thereby further improving the conductivity between the substrate 2 and the semiconductor chip 3 in the semiconductor device 1. The minimum melt viscosity of the encapsulating resin composition is more preferably 1000 Pa·s or higher. It is even more preferably 4200 Pa·s or lower.

[0026] The term "minimum melt viscosity" refers to the viscosity with the lowest value in a melt viscosity curve. Specifically, the melt viscosity and minimum melt viscosity are obtained by the following method. Specifically, a rheometer is used to measure the temperature dependence of the melt viscosity of the encapsulating resin composition under conditions of a temperature range of 40 to 200°C, a heating rate of 6°C / min, and an angular velocity of 6.283 rad / s. This results in a melt viscosity curve of the encapsulating resin composition. An example of a rheometer used for this measurement is the AR2000ex manufactured by TA Instruments Inc. The minimum melt viscosity of the encapsulating resin composition can be obtained by reading the minimum melt viscosity from the obtained melt viscosity curve.

[0027] The above-described properties of the encapsulating resin composition can be achieved by appropriately selecting components that can be contained in the encapsulating resin composition and appropriately adjusting the amounts of the components that can be contained in the encapsulating resin composition. Hereinafter, the components that can be contained in the encapsulating resin composition will be described in detail.

[0028] The encapsulating resin composition of the present embodiment contains the radical polymerizable monomer (A) and the thermoplastic elastomer (B) as described above.

[0029] (Radical polymerizable monomer) The radical polymerizable monomer (A) has, for example, a functional group having two or more unsaturated bonds in one molecule. By including the radical polymerizable monomer (A), the encapsulating resin composition can improve the curability of the encapsulating resin composition when preparing an encapsulating material from the encapsulating resin composition. For example, the radical polymerizable monomer (A) includes an acrylic compound (A1). Preferred components that the acrylic compound (A1) may contain will be described in more detail.

[0030] The acrylic compound (A1) contains, for example, a compound having two or more (meth)acryloyl groups per molecule. In this case, the acrylic compound (A1) can impart heat resistance to the sealing material 4. The acrylic compound (A1) more preferably contains a compound having 2 to 6 (meth)acryloyl groups per molecule, and even more preferably contains a compound having two (meth)acryloyl groups per molecule.

[0031] The acrylic compound (A1) preferably contains a di(meth)acrylate having a structure in which an alkylene oxide is added to a bisphenol skeleton, i.e., the acrylic compound (A1) preferably contains a compound having a structure represented by the following formula (I) (hereinafter also referred to as the acrylic compound (A11)):

[0032] [ka]

[0033] In formula (I), R 1 and R 2 R is independently a hydrogen atom or a methyl group. 3 is hydrogen, a methyl group, or an ethyl group. 4is a divalent organic group linking two aryl groups. It is preferable that each of m and n is a value of 0 or more and 20 or less, and the average value of m+n is a value of 2 or more and 30 or less. R 4 Examples of m+n include dialkylmethylene groups such as dimethylmethylene. The upper and lower limits of m+n are not particularly limited, but the upper limit of m+n is, for example, 30, and the lower limit of m+n is, for example, 2.

[0034] When the acrylic compound (A1) contains the acrylic compound (A11), the weight loss rate of the encapsulating resin composition can be further reduced. In addition, since the acrylic compound (A11) has two benzene rings as shown in formula (I), it can impart higher heat resistance to the encapsulating resin composition.

[0035] The acrylic compound (A11) preferably contains at least one of a compound represented by the following formula (II) (hereinafter also referred to as acrylic compound (A12)) and a compound represented by the following formula (III) (hereinafter also referred to as acrylic compound (A13)).

[0036] [ka]

[0037] In formula (II), R 3 is hydrogen, a methyl group, or an ethyl group. 4 is a divalent organic group connecting two aryl groups. In this case, it is preferable that each of m and n is a value of 0 or more and 20 or less, and the average value of m+n is a value of 2 or more and 30 or less. 4 Examples of m+n include dialkylmethylene groups such as dimethylmethylene. The upper and lower limits of m+n are not particularly limited, but the upper limit of m+n is, for example, 30, and the lower limit of m+n is, for example, 2. The acrylic compound (A12) is a compound represented by the formula (I) where R 1 and R 2 are both hydrogen atoms.

[0038] [ka]

[0039] In formula (III), R 3 is hydrogen, a methyl group, or an ethyl group, and R 4 is a divalent organic group connecting two aryl groups. In this case, it is preferable that each of m and n is a value of 0 or more and 20 or less, and the average value of m+n is a value of 2 or more and 30 or less. 4 Examples of m+n include dialkylmethylene groups such as dimethylmethylene. There are no particular restrictions on the upper and lower limits of m+n, but the upper limit of m+n is, for example, 30, and the lower limit of m+n is, for example, 2. The acrylic compound (A13) is a compound represented by the formula (I) where R 1 and R 2 are both methyl groups.

[0040] The acrylic compound (A1) more preferably contains an acrylic compound (A13). In this case, the weight loss rate of the encapsulating resin composition can be particularly suppressed. Therefore, the encapsulating material 4 formed from the encapsulating resin composition can be further prevented from generating voids.

[0041] More specific examples of the acrylic compound (A11) include EO-modified bisphenol A di(meth)acrylates (m+n=2.3 to 30) such as Aronix M-210, M-211B (manufactured by Toagosei), ABE-300, A-BPE-4, A-BPE-6, A-BPE-10, A-BPE-20, A-BPE-30, BPE-100, BPE-200, BPE-500, BPE-900, and BPE-1300N (manufactured by Shin-Nakamura Chemical Co., Ltd.); and EO-modified bisphenol F di(meth)acrylates such as Aronix M-208 (manufactured by Toagosei).

[0042] When the acrylic compound (A1) in the radical polymerizable monomer (A) contains the acrylic compound (A11), the content of the acrylic compound (A11) relative to the total amount of the acrylic compound (A1) is preferably 60% by mass or more and 100% by mass or less. In this case, the melt viscosity of the encapsulating resin composition can be further reduced. When the radical polymerizable monomer (A1) contains the acrylic compound (A13), the content of the acrylic compound (A13) relative to the total amount of the radical polymerizable monomer (A) is preferably 60% by mass or more and 100% by mass or less. In this case, voids are particularly unlikely to form in the encapsulating material 4 produced from the encapsulating resin composition, thereby further improving the conductivity between the substrate 2 and the semiconductor chip 3. Note that the "total amount of the acrylic compound (A1)" refers to the total amount of components contained as the acrylic compound (A1) in the radical polymerizable monomer (A) in the encapsulating resin composition.

[0043] The acrylic compound (A1) preferably further contains an epoxy(meth)acrylate. That is, the radical polymerizable monomer (A) preferably contains an epoxy(meth)acrylate. In this case, if the radical polymerizable monomer (A) contains an epoxy group, the reactivity of the encapsulating resin composition can be improved, and the heat resistance and adhesion of the encapsulating material 4 can be improved.

[0044] In the present disclosure, "epoxy (meth)acrylate" refers to a compound having at least one epoxy group and at least two (meth)acryloyl groups in one molecule. Epoxy (meth)acrylate is a compound that is not included in either the acrylic compound (A1) or the acrylic compound (A2).

[0045] Epoxy (meth)acrylate is an oligomer that is an addition reaction product between, for example, an epoxy resin and an unsaturated monobasic acid such as acrylic acid or methacrylic acid.

[0046] Epoxy resins, which are raw materials for epoxy (meth)acrylates, include diglycidyl compounds (bisphenol-type epoxy resins) obtained by condensation of bisphenols, such as bisphenols A and F, with epihalohydrin. The epoxy resins may also include epoxy resins having a phenol skeleton. Examples of epoxy resins having a phenol skeleton include polyglycidyl ethers (phenol novolac-type epoxy resins, cresol novolac-type epoxy resins) obtained by condensation of phenol novolacs, which are condensates of phenol or cresol with an aldehyde, such as formalin, with epihalohydrin. The epoxy resins may also include epoxy resins having a cyclohexyl ring.

[0047] The epoxy (meth)acrylate preferably includes, for example, bisphenol A type epoxy acrylate which is a solid or a liquid having a viscosity of 10 Pa·s or more at 25° C. The bisphenol A type epoxy acrylate is represented, for example, by the following formula (VI).

[0048] [ka]

[0049] In formula (VI), n represents a positive integer.

[0050] Commercially available examples of bisphenol A-type epoxy acrylates include Denacol Acrylate DA-250 (Nagase Chemicals, 60 Pa·s at 25°C), Denacol Acrylate DA-721 (Nagase Chemicals, 100 Pa·s at 25°C), Lipoxy VR-60 (Showa Polymer, solid at room temperature), and Lipoxy VR-77 (Showa Polymer, 100 Pa·s at 25°C).

[0051] The content of epoxy (meth)acrylate relative to the total amount of radical polymerizable monomer (A) is preferably, for example, 5% by mass or more and 15% by mass or less. In this case, the adhesion between the substrate 2 and the sealing material 4 can be further improved. The content of epoxy (meth)acrylate relative to the total amount of acrylic compound (A) is more preferably 7% by mass or more. The content of epoxy (meth)acrylate is more preferably 10% by mass or less.

[0052] When the radical polymerizable monomer (A) contains a compound having three or more (meth)acryloyl groups, examples of the compound having three or more (meth)acryloyl groups include pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol pentaacrylate, ethoxylated (3) trimethylolpropane triacrylate, ethoxylated (6) trimethylolpropane triacrylate, ethoxylated (9) trimethylolpropane triacrylate, propoxylated (6) trimethylolpropane triacrylate, and propoxylated (3) glyceryl triacrylate, highly propoxylated (55) glyceryl triacrylate, ethoxylated (15) trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, tetraethylene glycol diacrylate, dimethylolpropane tetraacrylate, tripropylene glycol diacrylate, pentaacrylate esters, 1,3-adamantanediol dimethacrylate, 1,3-adamantanediol diacrylate, 1,3-adamantanedimethanol dimethacrylate, and 1,3-adamantanedimethanol diacrylate.

[0053] It is also preferable that the acrylic compound (A1) further contains a (meth)acrylate having a fluorene skeleton. In this case, this can contribute to further improving the heat resistance of the curing agent produced from the encapsulating resin composition. Examples of the (meth)acrylate having a fluorene skeleton include at least one compound selected from the group consisting of bisphenoxyethanolfluorene, 4,4'-(9-fluorenylidene)diphenol, biscresolfluorene, and bisanilinefluorene.

[0054] In this embodiment, the acrylic compound (A1) is a compound having a (meth)acryloyl group, as described above. That is, the acrylic compound (A1) is a compound having at least one of an acryloyl group and a methacryloyl group. The acrylic compound (A1) may contain, for example, at least one of a monomer and an oligomer.

[0055] The radical polymerizable monomer (A) may contain various vinyl monomers other than the above components, for example, monofunctional vinyl monomers.

[0056] The amount of the radical polymerizable monomer (A) relative to the total solid content of the encapsulating resin composition is preferably 1% by mass or more and 22% by mass or less. In this case, the fluidity of the encapsulating resin composition can be ensured while preventing excessive increase in the reactivity of the encapsulating resin composition. In this embodiment, the "total solid content of the encapsulating resin composition" refers to the total amount of components blended into the encapsulating resin composition, excluding volatile components such as solvents. The amount of the radical polymerizable monomer (A) relative to the total solid content of the encapsulating resin composition is more preferably 4% by mass or more, and even more preferably 7% by mass or more. The amount of this radical polymerizable monomer (A) is more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0057] The mass ratio of the radical polymerizable monomer (A) to the total amount of the radical polymerizable monomer (A) and the thermoplastic elastomer (B) is preferably 5% by mass or more and 85% by mass or less. In this case, the encapsulating resin composition can achieve a good balance between favorable fluidity and good curability. The mass ratio of the radical polymerizable monomer (A) to the total amount of the radical polymerizable monomer (A) and the thermoplastic elastomer (B) is more preferably 20% by mass or more, and even more preferably 30% by mass or more. The mass ratio of this radical polymerizable monomer (A) is more preferably 82% by mass or less, and even more preferably 75% by mass or less.

[0058] (thermoplastic elastomer) The thermoplastic elastomer (B) is a component that has rubber elasticity at room temperature and exhibits thermoplasticity (plastic flow) when heated. In this embodiment, the thermoplastic elastomer (B) can impart good fluidity to the encapsulating resin composition when it is melted.

[0059] The thermoplasticity of the thermoplastic elastomer (B) upon heating can be confirmed by measuring its melt mass flow rate (hereinafter also referred to as "MFR"). The MFR of the thermoplastic elastomer (B) is preferably 1.8 g / 10 min or more and 13.5 g / min or less. Within this range, the melt viscosity of the encapsulating resin composition can be more easily maintained. Furthermore, if the MFR of the thermoplastic elastomer (B) is 1.8 g / min or more, voids can be more unlikely to occur. If the MFR of the thermoplastic elastomer (B) is 13.5 g / min or less, the connection reliability of the semiconductor device 1 can be further improved. The MFR of the thermoplastic elastomer (B) is more preferably 4.5 g / 10 min or more. This MFR is more preferably 9.0 g / min or less. The MFR of the thermoplastic elastomer (B) in the present disclosure can be measured using an ISO standard measurement method, for example, by the following method.

[0060] That is, first, the thermoplastic elastomer (B) is placed in the cylinder of the melt flow measuring device and heated to 230°C to melt it. Next, the molten thermoplastic elastomer (B) in the cylinder is extruded by the piston under a load of 21 N (2.16 kgf) for 10 minutes. The extruded thermoplastic elastomer (B) is cut to obtain a test piece. The weight of this test piece is measured, and the obtained value is taken as the MFR (unit: [g / 10 min]).

[0061] The thermoplastic elastomer (B) may be a styrene copolymer, such as a styrene-ethylene-butylene copolymer or a hydrogenated product thereof. The hydrogenated styrene-ethylene-butylene copolymer is, for example, a polymer obtained by adding hydrogen to a block copolymer of styrene and butadiene.

[0062] Specific examples of commercially available thermoplastic elastomers (B) include the H series, M series, and P series of hydrogenated styrene-based elastomers (SEBS) manufactured by Asahi Kasei Corporation.

[0063] In this embodiment, the mass ratio of the thermoplastic elastomer (B) to the total amount of the encapsulating resin composition is 3% by mass or more and 19% by mass or less. This makes it easy to ensure good fluidity of the encapsulating resin composition when heated and melted. The mass ratio of the thermoplastic elastomer (B) to the total amount of solids in the encapsulating resin composition is more preferably 4% by mass or more, and even more preferably 5% by mass or more. The mass ratio of this thermoplastic elastomer (B) is more preferably 18.5% by mass or less, and even more preferably 18% by mass or less.

[0064] (epoxy compounds) The encapsulating resin composition preferably further contains an epoxy compound (C). When the encapsulating resin composition contains an epoxy compound, the rate of the curing reaction of the encapsulating resin composition can be easily adjusted. That is, the epoxy compound (C) can adjust the reactivity and fluidity of the encapsulating resin composition under heating conditions. Therefore, when the encapsulating resin composition contains a radically polymerizable monomer (A) and an epoxy compound (C), the curing rate of the encapsulating resin composition can be easily adjusted. In particular, when the encapsulating resin composition is filled into the gap between the substrate 2 and the semiconductor chip 3 to produce a semiconductor device 1, the encapsulating resin composition can have appropriate curing properties even when mounted in a relatively short time. Therefore, by containing the radically polymerizable monomer (A) and the epoxy compound (C), the encapsulating resin composition can be easily flowed without excessive curing, making it less likely that the gap between the substrate 2 and the semiconductor chip 3 will be left unfilled. At the same time, the curing of the encapsulating resin composition proceeds appropriately, maintaining the connectivity between the substrate 2 and the semiconductor chip 3.

[0065] Examples of the epoxy compound (C) include alkylphenol novolac epoxy resins such as phenol novolac epoxy resins and cresol novolac epoxy resins; naphthol novolac epoxy resins; phenol aralkyl epoxy resins having a phenylene skeleton, biphenylene skeleton, or the like; biphenyl aralkyl epoxy resins; naphthol aralkyl epoxy resins having a phenylene skeleton, biphenylene skeleton, or the like; polyfunctional epoxy resins such as triphenol methane epoxy resins and alkyl-modified triphenol methane epoxy resins; triphenyl methane epoxy resins; tetrakisphenol ethane epoxy resins; dicyclopentadiene epoxy resins; Examples of the epoxy compound (C) include one or more components selected from the group consisting of diene epoxy resins, stilbene epoxy resins, bisphenol epoxy resins such as bisphenol A epoxy resins and bisphenol F epoxy resins, biphenyl epoxy resins, naphthalene epoxy resins, alicyclic epoxy resins, bromine-containing epoxy resins such as bisphenol A bromine-containing epoxy resins, glycidylamine epoxy resins obtained by reacting epichlorohydrin with polyamines such as diaminodiphenylmethane or isocyanuric acid, and glycidyl ester epoxy resins obtained by reacting epichlorohydrin with polybasic acids such as phthalic acid or dimer acid. The epoxy compound (C) is to be distinguished from the epoxy (meth)acrylates that may be included in the acrylic compound (A1) described above.

[0066] The mass proportion of the epoxy compound (C) relative to the total solid content of the encapsulating resin composition is preferably 0.3 mass % or more and 10 mass % or less, which makes it easy to adjust the curability and flowability of the encapsulating resin composition.

[0067] (Inorganic filler) The encapsulating resin composition preferably further contains an inorganic filler (D). In this case, the heat resistance of the cured product produced from the encapsulating resin composition can be further improved. Furthermore, when the encapsulating resin composition contains the inorganic filler (D), it is easier to further suppress the generation of voids in the encapsulating material 4 when the encapsulating resin composition is heated and ultrasonically vibrated to seal the gap between the substrate 2 and the semiconductor chip 3. In this case, peeling of the encapsulating material 4 from the substrate 2 and / or the semiconductor chip 3 can be further suppressed. Furthermore, the inorganic filler (D) can adjust the thermal expansion coefficient of the encapsulating material 4 formed from the cured product of the encapsulating resin composition.

[0068] In addition, the inorganic filler (D) can improve the thermal conductivity of the encapsulating material 4 made from the encapsulating resin composition, thereby allowing the heat generated from the semiconductor chip 3 to be efficiently dissipated through the encapsulating material 4.

[0069] The inorganic filler (D) can contain one or more materials selected from the group consisting of silica powders such as fused silica, synthetic silica, and crystalline silica; oxides such as alumina and titanium oxide; silicates such as talc, calcined clay, uncalcined clay, mica, and glass; carbonates such as calcium carbonate, magnesium carbonate, and hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate, and calcium sulfite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; and nitrides such as aluminum nitride, boron nitride, and silicon nitride. The fused silica may be either fused spherical silica or fused crushed silica. It is particularly preferred that the inorganic filler (D) contain at least one of silica and alumina.

[0070] The shape of the inorganic filler (D) is not particularly limited and may be crushed, needle-like, scaly, spherical, etc. In order to improve the dispersibility of the inorganic filler (D) in the encapsulating resin composition and to control the viscosity of the encapsulating resin composition, the inorganic filler (D) is preferably spherical.

[0071] The inorganic filler (D) preferably has an average particle size smaller than the dimension between the substrate 2 and the semiconductor chip 3 mounted thereon.

[0072] In order to improve the packing density of the inorganic filler (D) in the encapsulating resin composition and the encapsulant 4 and to adjust the viscosity of the encapsulating resin composition, the average particle size of the inorganic filler (D) is preferably 0.2 μm or more and 0.5 μm or less, and more preferably 0.2 μm or more and 0.4 μm or less. Note that the average particle size in this embodiment is a median diameter calculated from the results of particle size distribution measurement by laser light diffraction method.

[0073] In order to adjust the viscosity of the encapsulating resin composition and / or the physical properties of the encapsulating material 4, the inorganic filler (D) may contain two or more components having different average particle sizes.

[0074] The amount of inorganic filler (D) is, for example, 40% by mass or more and 75% by mass or less, based on the total solid content of the encapsulating resin composition. When the encapsulating resin composition contains inorganic filler (D), the content of inorganic filler (D) based on the total solid content of the encapsulating resin composition is preferably 45% by mass or more, more preferably 50% by mass or more. The content of inorganic filler (D) is preferably 65% ​​by mass or less, more preferably 60% by mass or less.

[0075] (Polymerization initiator) The encapsulating resin composition preferably further contains a polymerization initiator (E). When the encapsulating resin composition contains a polymerization initiator, the reactivity (e.g., reaction rate and reaction initiation temperature) of the radically polymerizable monomer (A) in the encapsulating resin composition can be easily adjusted. The polymerization initiator (E) preferably contains, for example, a thermal radical polymerization initiator. For example, when the polymerization initiator (E) contains a thermal radical polymerization initiator, the polymerization initiator (E) can control the reactivity of the radically polymerizable monomer compound (A) in the encapsulating resin composition and contribute to controlling the reaction rate of the encapsulating resin composition. Furthermore, when the encapsulating resin composition contains a polyphenylene ether resin (G) described below, the polymerization initiator (E) also easily suppresses the reactivity of the polyphenylene ether resin (G).

[0076] The polymerization initiator (E) contains, for example, an organic peroxide. The one-minute half-life temperature of the organic peroxide is preferably 90°C or higher and 195°C or lower, and more preferably 120°C or higher and 180°C or lower. Within this range, the encapsulating resin composition thickens quickly in the early stages of the process of heat-curing the encapsulating resin composition, to an extent that does not inhibit the wettability between the bump electrode 31 and the conductor wiring 21, and therefore, the generation of voids in the encapsulant 4 is more likely to be suppressed.

[0077] Specific examples of organic peroxides include benzoyl peroxide (1-minute half-life temperature 130°C), t-butylperoxy-2-ethylhexyl monocarbonate (1-minute half-life temperature 161.4°C), t-butylperoxybenzoate (1-minute half-life temperature 166.8°C), t-butylcumyl peroxide (1-minute half-life temperature 173.3°C), dicumyl peroxide (1-minute half-life temperature 175.2°C), These include α,α'-di(t-butylperoxy)diisopropylbenzene (1-minute half-life temperature 175.4°C), 2,5-dimethyl-2,5-di(t-butylperoxy)hexane (1-minute half-life temperature 179.8°C), di-t-butyl peroxide (1-minute half-life temperature 185.9°C), and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne (1-minute half-life temperature 194.3°C).

[0078] The polymerization initiator (E) may contain a polymerization initiator other than the compounds explained above.

[0079] (hardening agent) The encapsulating resin composition may further contain a curing agent (F). When the encapsulating resin composition contains the radically polymerizable monomer (A) and the epoxy compound (C), it preferably further contains a curing agent (F). The curing agent (F) can improve the curing property of, for example, the epoxy compound (C) in the encapsulating resin composition. In this case, the reaction curing rate of the encapsulating resin composition can be easily controlled. This reinforces the gap between the substrate 2 and the semiconductor chip 3 and further reduces the likelihood of the gap being left unfilled. Furthermore, in this case, the encapsulating resin composition filled in the gap between the substrate 2 and the semiconductor chip 3 is easy to handle when post-cured. Furthermore, in this case, it is possible to more effectively prevent voids from remaining in the cured product of the encapsulating resin composition, and it is also possible to more effectively prevent the encapsulant 4 formed from the cured product of the encapsulating resin composition from peeling from the substrate 2. Therefore, sealing the gap between the substrate 2 and the semiconductor chip 3 with the cured product of this encapsulating resin composition can further improve the reliability of the semiconductor device 1.

[0080] The curing agent (F) contains, for example, a phenolic resin. More specifically, the curing agent (F) contains at least one component selected from the group consisting of novolac resins such as phenolic novolac resins, cresol novolac resins, and naphthol novolac resins; dicyclopentadiene-type phenolic resins such as dicyclopentadiene-type phenolic novolac resins and dicyclopentadiene-type naphthol novolac resins; terpene-modified phenolic resins; bisphenol resins such as bisphenol A and bisphenol F; and triazine-modified novolac resins. It is more preferable that the curing agent (F) contains a phenolic novolac resin.

[0081] When the encapsulating resin composition contains the epoxy compound (C), it may further contain a curing accelerator that accelerates the curing of the epoxy compound (C).

[0082] The encapsulating resin composition may further contain a polyphenylene ether resin (G). In this embodiment, the encapsulating resin composition further contains a polyphenylene ether resin (G). In this case, the viscosity of the encapsulating resin composition can be easily adjusted so as not to be excessively high, which facilitates improving the filling ability of the encapsulating resin composition in the gap between the substrate 2 and the semiconductor chip 3. This further reduces the likelihood of the encapsulating resin composition being left unfilled. Furthermore, as described below, the polyphenylene ether resin (G) has a radically polymerizable substituent (g1). Therefore, when the encapsulating resin composition is thermally cured, the polyphenylene ether resin (G) and the radically polymerizable monomer (A) polymerize to form a macromolecule. That is, the polyphenylene ether resin (G) is incorporated into the skeleton of the macromolecule. As a result, the cured product of the encapsulating resin composition can have high heat resistance and moisture resistance. Therefore, when the encapsulating material 4 is produced from the encapsulating resin composition, the semiconductor device 1 has excellent heat resistance and moisture resistance.

[0083] The polyphenylene ether resin (G) has a radically polymerizable substituent (g1) at its terminal. The polyphenylene ether resin (G) has, for example, a polyphenylene ether chain (g2) and the substituent (g1) bonded to the terminal of the polyphenylene ether chain (g2).

[0084] The structure of the substituent (g1) is not particularly limited as long as it has radical polymerizability. Examples of the substituent (g1) include a group having a carbon-carbon double bond.

[0085] The substituent (g1) is preferably a group having a carbon-carbon double bond. In this case, the substituent (g1) reacts with the radical polymerizable monomer (A) to incorporate the polyphenylene ether resin (G) into the skeleton of the macromolecule, and as a result, the cured product of the encapsulating resin composition can have high heat resistance and moisture resistance.

[0086] The substituent (g1) has, for example, a structure shown in the following formula (1) or a structure shown in the following formula (2).

[0087] [ka]

[0088] In formula (1), R is hydrogen or an alkyl group. When R is an alkyl group, the alkyl group is preferably a methyl group.

[0089] [ka]

[0090] In formula (2), n is an integer of 0 to 10, for example, n=1. In formula (2), Z is an arylene group, and R 1 ~R 3 are each independently hydrogen or an alkyl group. When n in formula (2) is 0, Z is directly bonded to the end of the polyphenylene ether chain (g2) in the polyphenylene ether resin (G).

[0091] The substituent (d1) particularly preferably has a structure shown in formula (1).

[0092] The polyphenylene ether resin (G) contains, for example, a compound having a structure represented by the following formula (3).

[0093] [ka]

[0094] In formula (3), Y is an alkylene group having 1 to 3 carbon atoms or a direct bond. Y is, for example, a dimethylmethylene group. In formula (3), X is a substituent (g1), for example, a group having the structure shown in formula (1) or a group having the structure shown in formula (2). It is particularly preferable that X is a group having the structure shown in formula (1). Furthermore, in formula (3), s is a number of 0 or more, t is a number of 0 or more, and the sum of s and t is a number of 1 or more. s is preferably a number of 0 or more and 20 or less, t is preferably a number of 0 or more and 20 or less, and the sum of s and t is preferably a number of 1 or more and 30 or less.

[0095] The encapsulating resin composition preferably further contains a flux. Examples of fluxes include organic acids. When the encapsulating resin composition contains an organic acid, the action of the organic acid removes the oxide film on the surface of the bump electrode 31 during reflow, ensuring good connection reliability between the semiconductor chip 3 and the substrate 2. The organic acid may contain one or more compounds selected from the group consisting of sebacic acid, abietic acid, glutaric acid, succinic acid, malonic acid, oxalic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, diglycolic acid, thiodiglycolic acid, phthalic acid, isophthalic acid, terephthalic acid, propanetricarboxylic acid, citric acid, benzoic acid, and tartaric acid.

[0096] The encapsulating resin composition may contain maleic acid-modified polybutadiene. When the encapsulating resin composition contains maleic acid-modified polybutadiene, the adhesion between the encapsulant 4 and the substrate 2 can be particularly improved. The amount of maleic acid-modified polybutadiene is preferably 1% by mass or more and 5% by mass or less based on the total solid content of the encapsulating resin composition.

[0097] The encapsulating resin composition may contain components other than those described above. For example, the encapsulating resin composition may further contain a thermosetting compound other than the radical polymerizable monomer (A), the epoxy compound (C), the curing agent (F), and the polyphenylene ether resin (G). Examples of such a thermosetting compound include compounds that can undergo a thermosetting reaction with the radical polymerizable monomer (A). A specific example of such a thermosetting compound is a bismaleimide resin.

[0098] The encapsulating resin composition may further contain additives other than the above components within a range that does not impair the effects of the present embodiment. Examples of the additives include a radical scavenger, a silane coupling agent, an antifoaming agent, a leveling agent, a stress reducing agent, and a pigment.

[0099] The encapsulating resin composition can be prepared, for example, by the following method.

[0100] First, the components that can be contained in the encapsulating resin composition described above are mixed simultaneously or sequentially to obtain a mixture. In this case, it is preferable to mix the components other than the inorganic filler (D) first, for example. This mixture is stirred and mixed while optionally undergoing a heating treatment or cooling treatment. Next, if necessary, the inorganic filler (D) is added to this mixture. Next, this mixture is stirred and mixed again while optionally undergoing a heating treatment or cooling treatment. This allows the encapsulating resin composition to be obtained. To stir the mixture, for example, a disper, planetary mixer, ball mill, three-roll mill, bead mill, etc. can be used in combination as needed.

[0101] The encapsulating resin composition prepared as described above may be molded into, for example, a sheet or a paste. For example, the encapsulating resin composition is preferably molded into a sheet. In this case, an encapsulating sheet material can be produced from the encapsulating resin composition. A cured product of the encapsulating resin composition can also be produced from an encapsulating sheet material 40 (hereinafter, sometimes simply referred to as "sheet material 40"). Therefore, the sheet material 40 (see FIG. 2) is suitable for forming the encapsulating material 4 in the semiconductor device 1 (see FIG. 1), similar to the encapsulating resin composition. However, the shape of the encapsulating material produced from the encapsulating resin composition is not limited to these.

[0102] [Laminated sheet] The sheet material 40 and the laminated sheet 6 including the sheet material 40 will be described in detail below with reference to FIG.

[0103] When producing the sheet material 40, for example, a liquid composition containing the encapsulating resin composition is prepared by first adding a solvent, if necessary, to a mixture containing the above components. Note that the encapsulating resin composition does not need to contain a solvent as long as it can be prepared in a liquid form.

[0104] The solvent may be, for example, at least one component selected from the group consisting of methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methyl ethyl ketone, acetone, isopropyl acetone, toluene, and xylene. In this case, the amount of the solvent can be appropriately set, but may be, for example, 40% by mass or more and 60% by mass or less with respect to the total solid content of the encapsulating resin composition. Note that the solvent may volatilize when the liquid composition is formed into a sheet to produce the encapsulating sheet material 40.

[0105] A support sheet 60 is prepared, and a liquid composition is applied to one surface of the support sheet 60. The support sheet 60 can include a suitable plastic sheet 61, such as polyethylene terephthalate. The support sheet 60 may also include a plastic sheet 61 and an adhesive layer 62 overlying the plastic sheet 61. The adhesive layer 62 has appropriate adhesive strength and can be used to secure the support sheet 60 to a suitable base. The adhesive layer 62 may be reactively curable. In this case, the support sheet 60 can be firmly secured to the base by placing the support sheet 60 on the suitable base and then curing the adhesive layer 62. The adhesive layer 62 can be made of at least one component selected from the group consisting of, for example, acrylic resin, synthetic rubber, natural rubber, and polyimide resin.

[0106] When the support sheet 60 comprises a plastic sheet 61 and an adhesive layer 62, the liquid composition is applied to the surface of the plastic sheet 61 opposite to the adhesive layer 62.

[0107] Subsequently, the liquid composition is dried and / or semi-cured by heating on the support sheet 60. The heating conditions for the liquid composition at this time are preferably, for example, a heating temperature of 100°C or higher and 120°C or lower, and a heating time of 5 minutes or higher and 15 minutes or lower. This allows the sheet material 40 to be produced on the support sheet 60, and also provides a laminated sheet 6 including the sheet material 40 and the support sheet 60 that supports it. When the encapsulating resin composition contains a polyphenylene ether resin (G), the encapsulating resin composition can be easily formed into a sheet, and therefore the sheet material 40 can be particularly easily produced.

[0108] The thickness of the sheet material 40 is, for example, 10 μm or more and 50 μm or less, but is not limited to this and may be an appropriate value according to the thickness of the sealing material 4 in the semiconductor device 1.

[0109] As shown in Fig. 2, the laminate sheet 6 may further include a protective film 64 that covers the sheet material 40. The material of the protective film 64 is not particularly limited. Furthermore, when the support sheet 60 includes an adhesive layer 62, the laminate sheet 6 may further include a cover sheet 63 that covers the adhesive layer 62, as shown in Fig. 2. The material of the cover sheet 63 is also not particularly limited.

[0110] The cured product of the encapsulating resin composition is obtained by thermally curing the encapsulating resin composition and / or the sheet material 40. The cured product of the encapsulating resin composition can be suitably used as the encapsulant 4 that seals the gap between the substrate 2 and the semiconductor chip 3 mounted on the substrate 2.

[0111] In this case, the cured product can have high heat resistance, and therefore the semiconductor device 1 including the sealing material 4 made of the cured product can have high heat resistance reliability.

[0112] The encapsulating resin composition is placed in the gap between the substrate 2 and the semiconductor chip 3, and when heated and ultrasonically vibrated for a relatively short period of time, the encapsulating resin composition (sheet material 40) is cured to form the encapsulating material 4, thereby reinforcing the connection between the substrate 2 and the semiconductor chip 3 and ensuring electrical conductivity. In this case, voids are less likely to occur in the encapsulating material 4 in the semiconductor device 1. This further improves the connection reliability of the semiconductor device 1.

[0113] In this way, the encapsulating resin composition and the encapsulating sheet material 40 are suitable as underfill, and the semiconductor device 1 can be produced by sealing the gap between the substrate 2 and the semiconductor chip 3 with this encapsulating resin composition by pre-supply underfilling.

[0114] [Semiconductor Devices] FIG. 1A shows an example of a semiconductor device 1. This semiconductor device 1 includes a substrate 2, a semiconductor chip 3 mounted on the substrate 2, and an encapsulant 4 that seals the gap between the substrate 2 and the semiconductor chip 3. The semiconductor chip 3 is preferably mounted face-down on the substrate 2. The encapsulant 4 is made of a cured product of an encapsulating resin composition. In this embodiment, as described below, producing the encapsulating material 4 from the encapsulating resin composition includes applying ultrasonic vibrations to the encapsulating resin composition while heating it, thereby sealing the gap between the substrate 2 and the semiconductor chip 3 and electrically connecting the bump electrodes 31 and the conductor wiring 21.

[0115] In this embodiment, the semiconductor chip 3 has bump electrodes 31 on the surface facing the base material 2, and the base material 2 has conductor wiring 21 on the surface facing the semiconductor chip 3. The bump electrodes 31 and the conductor wiring 21 are aligned and connected via solder bumps 32. The bump electrodes 31 and the conductor wiring 21 are embedded in the sealing material 4.

[0116] The semiconductor device 1 according to this embodiment can be fabricated, for example, as follows.

[0117] First, a substrate 2 having conductor wiring 21, a semiconductor chip 3 having bump electrodes 31, and an encapsulating resin composition are prepared. The encapsulating resin composition may be an encapsulating sheet material 40. The semiconductor chip 3 having bump electrodes 31 is placed on the surface of the substrate 2 having conductor wiring 21, with the encapsulating resin composition interposed therebetween, so that the conductor wiring 21 and the bump electrodes 31 face each other. In this state, ultrasonic vibrations are applied to the encapsulating resin composition while heating it, thereby sealing the gap between the substrate 2 and the semiconductor chip 3 and electrically connecting the bump electrodes 31 and the conductor wiring 21. In other words, sealing the gap between the substrate 2 and the semiconductor chip 3 includes applying ultrasonic vibrations to the solder bumps 32 while heating the solder bumps 32 and the encapsulating resin composition, with the solder bumps 32 and the encapsulating resin composition interposed between the substrate 2 and the semiconductor chip 3.

[0118] Next, the semi-cured encapsulating resin composition is further heated to completely cure the encapsulating resin composition, thereby forming an encapsulant 4 made of the cured encapsulating resin composition. This allows for the production of a semiconductor device 1 in which the gap between the substrate 2 and the semiconductor chip 3 is encapsulated with the encapsulant 4. In the semiconductor device 1 of this embodiment, the gap between the substrate 2 and the semiconductor chip 3 is encapsulated with the cured encapsulating resin composition, i.e., the encapsulant 4, thereby reinforcing the connection between the substrate 2 and the semiconductor chip 3 and making it less likely that the gap between the substrate 2 and the semiconductor chip 3 will be left unfilled. This provides the semiconductor device 1 of this embodiment with excellent electrical conductivity reliability. Furthermore, in the semiconductor device 1, the encapsulant 4 can encapsulate the gap between the substrate 2 and the semiconductor chip 3 while suppressing the generation of voids.

[0119] Another example of the method for manufacturing the semiconductor device 1 will be described in more detail with reference to Figures 3A to 3D, but the method for manufacturing the semiconductor device 1 of this embodiment is not limited to the following method.

[0120] First, a laminated sheet 6 including a base material 2, a semiconductor chip 3, and an encapsulating resin composition (sheet material 40) is prepared.

[0121] The substrate 2 is, for example, a motherboard, a package substrate, or an interposer substrate. In this embodiment, the substrate 2 includes an insulating substrate made of glass epoxy, polyimide, polyester, ceramic, or the like, and conductor wiring 21 made of a conductor such as copper formed on the surface thereof.

[0122] The semiconductor chip 3 has, on one surface of a silicon wafer having a circuit formed by an appropriate method such as photolithography, bump electrodes 31 connected to the circuit. In this embodiment, the bump electrodes 31 on the semiconductor chip 3 have solder bumps 32. Instead of the semiconductor chip 3 having the bump electrodes 31, the conductor wiring 21 on the base material 2 may have the solder bumps 32, or both the bump electrodes 31 and the conductor wiring 21 may have the solder bumps 32. In other words, it is sufficient that at least one of the bump electrodes 31 on the semiconductor wafer and the conductor wiring 21 on the base material 2 has the solder bumps 32. The solder bumps 32 are preferably made of lead-free solder with a melting point of 210°C or higher, such as Sn-3.5Ag (melting point 221°C), Sn-2.5Ag-0.5Cu-1Bi (melting point 214°C), Sn-0.7Cu (melting point 227°C), or Sn-3Ag-0.5Cu (melting point 217°C).

[0123] The semiconductor chips 3 may be formed from individual sheets obtained by cutting a laminated product made from the laminate sheet 6 and a semiconductor wafer to an appropriate size. Specifically, the individual sheets are formed by overlaying the sheet material 40 of the laminate sheet 6 on the surface of the semiconductor wafer on which the bump electrodes 31 are located. After peeling the protective film 64 from the sheet material 40 of the laminate sheet 6, the sheet material 40, which is overlaid on the support sheet 60, is placed on the surface of the semiconductor wafer on which the bump electrodes 31 are located. Next, the semiconductor wafer is diced by cutting the sheet material 40 together with the sheet material 40. For example, after peeling the cover sheet 63 from the adhesive layer 62 of the support sheet 60, the adhesive layer 62 is placed on a base, and the adhesive layer 62 is cured as necessary. This fixes the support sheet 60 to the base with the sheet material 40 overlaid on the support sheet 60. In this state, the semiconductor wafer is cut together with the sheet material 40. This produces a component (also referred to as a chip component) that includes the semiconductor chips 3 cut from the semiconductor wafer and the individual sheets cut from the sheet material 40. This chip component is removed from the support sheet 60. The semiconductor chip 3 in the chip component has bump electrodes 31, and the individual sheet overlaps the surface of the semiconductor chip 3 on which the bump electrodes 31 are located.

[0124] Next, the semiconductor chip 3 is mounted face-down on the substrate 2 with the sheet material 40 interposed between the substrate 2 and the semiconductor chip 3. In this embodiment, as shown in FIG. 3A, a flip-chip bonder 70 equipped with a bonding head 71 and a stage 72 and capable of applying ultrasonic vibrations is used to perform the mounting process as follows. In this embodiment, the stage 72 of the flip-chip bonder 70 is configured to apply ultrasonic vibrations, but this is not a limitation. Any device capable of applying ultrasonic vibrations to the conductor wiring 21 and the bump electrodes 31 may be used. For example, the bonding head 71 may be capable of applying ultrasonic vibrations, or both the bonding head 71 and the stage 72 may be capable of applying ultrasonic vibrations. A specific example of the flip-chip bonder 70 is the FCB3 manufactured by Panasonic Corporation. In addition, although the sheet material 40 is pre-placed on the semiconductor chip 3 in FIGS. 3A to 3D and the above description, this is not a limitation. For example, the substrate 2 may be placed on the stage 72, and the semiconductor chip 3 may be held by the bonding head 71, with the sheet material 40 interposed between the substrate 2 and the semiconductor chip 3, or the encapsulating resin composition may be applied to the substrate 2 and interposed between the substrate 2 and the semiconductor chip 3. Note that, although the above description has been given of the case where the encapsulating resin composition is in sheet form (i.e., the above-mentioned sheet material 40), the encapsulating material may also be in paste form.

[0125] As shown in FIG. 3A, a substrate 2 having conductor wiring 21 is supported on a stage 72, and is held by a bonding head 71 so that the bump electrodes 31 of the semiconductor chip 3 face the substrate 2 supported on the stage 72. An encapsulating resin composition is interposed between the substrate 2 and the semiconductor chip 3. In this state, the bonding head 71 is moved toward the stage 72 as shown in FIG. 3B. This places the semiconductor chip 3 on the substrate 2 with the sheet material 40 interposed therebetween. At this time, the semiconductor chip 3 and the substrate 2 are aligned so that the bump electrodes 31 on the semiconductor chip 3 and the conductor wiring 21 on the substrate 2 overlap.

[0126] In this state, ultrasonic vibrations are applied while heating the encapsulating resin composition, semiconductor chip 3, and substrate 2 via bonding head 71 and stage 72, thereby heating solder bumps 32 and the encapsulating resin composition. The heating temperature is set appropriately depending on the composition of solder bumps 32 and the composition of the encapsulating resin composition. The heating temperature is preferably, for example, 150°C or higher and 210°C or lower, and more preferably 170°C or higher and 200°C or lower.

[0127] The conditions such as the time for applying ultrasonic vibration and the frequency of vibration are set appropriately, but for example, the time for applying vibration is 0.1 seconds or more and 5.0 seconds or less, and the frequency of vibration is 10 kHz or more and 50 kHz or less.

[0128] Furthermore, when applying ultrasonic vibrations while heating the encapsulating resin composition, semiconductor chip 3, and substrate 2 through bonding head 71 and stage 72, a load may be applied by bonding head 71 to substrate 2, semiconductor chip 3, and encapsulating resin composition on stage 72. For example, bonding head 71 may be configured to apply pressure in the direction of stage 72, thereby applying a load by pressing bonding head 71 with the encapsulating resin composition interposed between substrate 2 and semiconductor chip 3. The load conditions in this case are set appropriately, but the load may be, for example, 10 N or more and 200 N or less.

[0129] Furthermore, the time from the start of heating to mounting the encapsulating resin composition and semiconductor chip 3 on the substrate 2 while applying ultrasonic vibrations is preferably 0.5 to 2.5 seconds, more preferably 1.0 to 2.0 seconds. A time of 0.5 seconds or more can improve the production efficiency of the semiconductor device 1 while ensuring conductivity, while a time of 2.5 seconds or less can achieve good conductivity without reducing production efficiency. Furthermore, within this range, the production time per chip is short, thereby improving production efficiency compared to conventional mounting methods such as thermocompression bonding.

[0130] In this manner, when the solder bumps 32 and the encapsulating resin composition are heated and ultrasonic vibrations are applied with the encapsulating resin composition interposed between the base material 2 and the semiconductor chip 3, the solder bumps 32 melt, electrically connecting the bump electrodes 31 and the conductor wiring 21. Furthermore, the encapsulating resin composition melts and then thermally hardens to form an encapsulant 4 as shown in FIG. 3C , and thereby the gap between the semiconductor chip 3 and the base material 2 is sealed with the encapsulant 4.

[0131] Next, as shown in FIG. 3D, the bonding head 71 is moved upward and separated from the semiconductor chip 3. In this embodiment, after separating the bonding head 71 from the semiconductor chip 3, the encapsulant 4 in the semiconductor device 1 is heated (after-cured) to further harden. This can further increase the connection strength between the base material 2 and the semiconductor chip 3 in the semiconductor device 1. In this embodiment, the encapsulant 4 in the semiconductor device 1 is made from the encapsulating resin composition described above. This can reduce remaining voids in the encapsulant 4 and ensure high connectivity. This allows the semiconductor device 1 to have high reliability.

[0132] As described above, the semiconductor device 1 shown in Fig. 1A is obtained by mounting the semiconductor chip 3 on the base material 2. As described above, in this embodiment, even if the temperature of the bonding head 71 is set to a relatively low temperature, it is possible to seal the gap between the base material 2 and the semiconductor chip 3 with the sealing material 4. In the semiconductor device 1 produced in this manner, the connection between the base material 2 and the semiconductor chip 3 is reinforced by filling the gap between the base material 2 and the semiconductor chip 3 with the sealing material 4, and electrical continuity between the base material 2 and the semiconductor chip 3 is also ensured.

[0133] Furthermore, after manufacturing the semiconductor device 1 as described above, it is also possible to successively manufacture another semiconductor device 1 using the same flip chip bonder 70. This makes it possible to improve the manufacturing efficiency of the semiconductor device 1.

[0134] In another embodiment of the present invention, the semiconductor device 1 may be a multi-layer stacked semiconductor device 1, in which encapsulants 4 and semiconductor chips 3 are alternately stacked on a substrate 2, as shown in FIG. 1B . To manufacture the multi-layer stacked semiconductor device 1, the substrate 2 and semiconductor chip 3 are stacked together with an encapsulant 4 formed from an encapsulating resin composition, and then another semiconductor chip 3 and the encapsulating resin composition are heated and ultrasonically vibrated using the same flip-chip bonder 70. A new semiconductor chip 3 is stacked on the previously stacked semiconductor chip 3 with the newly formed encapsulant 4 interposed therebetween. By repeating this process, a multi-layer stacked semiconductor device 1 can be fabricated in which multiple encapsulants 4 and semiconductor chips 3 are stacked on the substrate 2. While FIG. 1B shows the semiconductor device 1 with four semiconductor chips stacked, the number of stacked layers is not limited to this and can be appropriately determined depending on the purpose, application, etc.

[0135] [Aspect] The present disclosure includes the following aspects.

[0136] The encapsulating resin composition of the first embodiment is used to seal a gap between a substrate (2) and a semiconductor chip (3) mounted on the substrate (2). The encapsulating resin composition contains a radically polymerizable monomer (A) and a thermoplastic elastomer (B). The mass ratio of the thermoplastic elastomer (B) to the total amount of the encapsulating resin composition is 3 mass% or more and 19 mass% or less. The encapsulating resin composition has a minimum melt viscosity of 500 Pa·s or more and 5000 Pa·s or less at 60°C or more and 180°C or less.

[0137] According to this embodiment, when the encapsulating resin composition is used to seal the gap between the substrate (2) and the semiconductor chip (3) mounted on the substrate (2), high connectivity between the substrate (2) and the semiconductor chip (3) can be achieved and voids are less likely to occur, even if the mounting time of the semiconductor chip (3) on the substrate (2) is shortened.

[0138] In the second aspect, in the first aspect, sealing the gap between the substrate (2) and the semiconductor chip (3) includes applying ultrasonic vibration to the solder bumps while heating the solder bumps and the sealing resin composition, with the solder bumps and the sealing resin composition being interposed between the substrate (2) and the semiconductor chip (3).

[0139] The encapsulating resin composition can be suitably used as an encapsulating material for producing an encapsulant (4) by heating the solder bumps and the encapsulating resin composition while applying ultrasonic vibrations to the solder bumps.

[0140] In a third aspect, in the first or second aspect, the mass proportion of the radical polymerizable monomer (A) relative to the total solid content of the encapsulating resin composition is 1 mass % or more and 22 mass % or less.

[0141] According to this embodiment, the fluidity of the encapsulating resin composition can be ensured while preventing the reactivity of the encapsulating resin composition from being excessively increased.

[0142] In a fourth aspect, in any one of the first to third aspects, the melt mass flow rate (MFR) of the thermoplastic elastomer (B) measured under conditions of a heating temperature of 230°C and a load of 21 N is 1.8 g / 10 min or more and 13.5 g / 10 min or less.

[0143] According to this embodiment, the melt viscosity of the encapsulating resin composition can be more easily maintained, voids can be less likely to occur, and the connection reliability in the semiconductor device (1) can be further improved.

[0144] In a fifth aspect, in any one of the first to fourth aspects, the mass proportion of the radical polymerizable monomer (A) relative to the total amount of the radical polymerizable monomer (A) and the thermoplastic elastomer (B) is 5 mass% or more and 85 mass% or less.

[0145] According to this embodiment, the encapsulating resin composition can have a good balance of suitable fluidity and good curability.

[0146] In a sixth aspect, in any one of the first to fifth aspects, the encapsulating resin composition further contains an epoxy compound (C).

[0147] According to this embodiment, the reaction rate and fluidity of the encapsulating resin composition under heating conditions can be adjusted by the epoxy compound (C).

[0148] In a seventh aspect, in any one of the first to sixth aspects, the encapsulating resin composition further contains an inorganic filler (D). The mass ratio of the inorganic filler (D) to the total amount of the encapsulating resin composition is 50 mass % or more and 65 mass % or less.

[0149] In an eighth aspect, in any one of the first to seventh aspects, the encapsulating resin composition further contains a polymerization initiator (E).

[0150] According to this embodiment, the reactivity of the radical polymerizable monomer (A) can be adjusted by the polymerization initiator (E).

[0151] In a ninth aspect, in any one of the first to eighth aspects, the encapsulating resin composition further contains a flux.

[0152] According to this embodiment, good connection reliability between the semiconductor chip (3) and the substrate (2) can be ensured.

[0153] A semiconductor device (1) according to a tenth aspect includes a semiconductor chip (3) mounted face-down on a substrate (2), and an encapsulant (4) that seals the gap between the substrate (2) and the semiconductor chip (3). The encapsulant (4) is made of a cured product of the encapsulating resin composition according to any one of the first to ninth aspects.

[0154] According to this embodiment, even if the mounting time of the semiconductor chip (3) on the substrate (2) is shortened, high connectivity between the substrate (2) and the semiconductor chip (3) can be achieved, and voids are less likely to occur in the sealing material (4).

[0155] A method for manufacturing a semiconductor device (1) according to an eleventh aspect is a method for manufacturing a semiconductor device (1) including a substrate (2), a semiconductor chip (3) mounted on the substrate (2), and an encapsulant (4) that encapsulates a gap between the substrate (2) and the semiconductor chip (3). The method for manufacturing the semiconductor device (1) includes applying ultrasonic vibration to the solder bumps (32) while heating the solder bumps (32) and the encapsulating resin composition according to any one of the first to ninth aspects, with the solder bumps (32) and the encapsulating resin composition interposed between the substrate (2) and the semiconductor chip (3).

[0156] According to this embodiment, the ultrasonic vibration can shorten the heating time while realizing electrical connection between the substrate (2) and the semiconductor chip (3) through the solder bumps (32). [Example]

[0157] [Examples 1 to 7 and Comparative Examples 1 to 4] (1) Preparation of encapsulating resin composition A liquid composition for producing a sealing material (dried material or sheet material) of each of the Examples and Comparative Examples was prepared as follows.

[0158] First, the components shown in the composition column of Table 1 were prepared. Of these components, the radically polymerizable monomer was weighed and stirred and mixed using a disperser. Subsequently, the appropriate components other than the inorganic filler were added to the radically polymerizable monomer and mixed to prepare a first mixed liquid. When a polyphenylene ether resin was added, the polyphenylene ether resin was dissolved in a 1:1 mixed solvent of methyl ethyl ketone and toluene to prepare a second mixed liquid. The first mixed liquid and the inorganic filler were then added to the second mixed liquid, and the mixture was stirred using a disperser. Subsequently, the inorganic filler was dispersed by mixing using a bead mill. Thus, a liquid composition containing an encapsulating resin composition was prepared.

[0159] The details of the components shown in the composition column in the table are as follows: In the table, the numerical values ​​of the components indicate the mass percentage (%) when the total solid content (100%) of the encapsulating resin composition is taken as 100. Furthermore, in the table, [phr] is an abbreviation for "per hundred resin" and is a unit that represents the percentage of a component when the total solid content excluding the inorganic filler of the encapsulating resin composition is taken as 100. -Component (A): radical polymerizable monomer Radical polymerizable monomer 1: ethoxylated bisphenol A dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product number BPE-100N (in formula (III), R 3 is a hydrogen atom, R 4 is a dimethylmethylene group, m+n=2.6), weight loss rate 0.22%. Radical polymerizable monomer 2: bisphenol A epoxy acrylate (Showa High Polymer Co., Ltd., product number VR-77, weight loss rate 0.51%). -(B) Component: Thermoplastic elastomer Thermoplastic elastomer 1: Asahi Kasei Corporation, product name: Tuftec H1041 (MFR measured at a heating temperature of 230°C and a load of 2.16 kgf: 5.0 g / 10 min). Thermoplastic elastomer 2: Asahi Kasei Corporation, product name: Tuftec H1052 (MFR measured at a heating temperature of 230°C and a load of 2.16 kgf: 13.0 g / 10 min). Thermoplastic elastomer 3: Asahi Kasei Corporation, product name: Tuftec H1043 (MFR measured at a heating temperature of 230°C and a load of 2.16 kgf: 2.0 g / 10 min). -(C) Component: Epoxy compound Epoxy compound: Bisphenol A type epoxy resin (manufactured by Nippon Steel Chemical & Material Co., Ltd., product name YD-8125. Epoxy equivalent 168-178g / eq., viscosity 3900-5300mPa·s.). -(D) Component: Inorganic filler Inorganic filler 1: Filler (silica powder), manufactured by Tokuyama Corporation, product number NHM-24D (average particle size 0.24 μm). Inorganic filler 2: Filler (spherical silica), manufactured by Admatechs Co., Ltd., product number SO-E2 (particle size 0.4 μm to 0.6 μm, specific surface area 4 m 2 / g~7m 2 / g). -Component (E): Polymerization initiator Polymerization initiator: Dicumyl peroxide, manufactured by NOF Corporation, product name Percumyl D (thermal radical polymerization initiator). -(F) Component: Hardener Hardener 1: Phenol novolac resin (Meiwa Kasei Co., Ltd. Product name DL-75. Melting point 75°C. Hardener 2: Liquid phenolic resin (Meiwa Kasei Co., Ltd. Product name MEH-8000H. Hydroxy equivalent 139-143g / eq. Viscosity 1500-3500mPa·s). -(others) Modified polybutadiene: Maleic acid modified polybutadiene, manufactured by Cray Valley, product name Ricobond 1756. Curing accelerator: Imidazole-based epoxy resin curing accelerator (product name 2E4MZ, manufactured by Shikoku Kasei Co., Ltd.). Polyphenylene ether resin: modified polyphenylene ether resin having the structure shown in formula (3) above, where X in formula (3) is a group having the structure shown in formula (1) above (R is a methyl group), manufactured by SABIC, product number SA9000, weight loss rate 0.36%. Silane coupling agent: Shin-Etsu Silicone Co., Ltd. Product name: X-12-1050. ·Flux: Glutaric acid.

[0160] (2) Fabrication of semiconductor devices Using the encapsulating resin composition prepared in (1) above, a semiconductor device was fabricated as follows.

[0161] A Walts TEG IP80 (10 mm × 10 mm × 300 μm) manufactured by Walts was prepared as the substrate. A Walts TEG CC80 (7.3 mm × 7.3 mm × 100 μm) manufactured by Walts was prepared as the semiconductor wafer. The semiconductor wafer had 1048 bump electrodes, each with a 30 μm-high Cu pillar and a 15 μm-high solder bump on top of it, with a pitch of 80 μm between adjacent solder bumps.

[0162] A polyethylene terephthalate film was prepared as a support sheet. The liquid composition prepared in (1) above was applied to this support sheet using a bar coater to form a film with a wet thickness of 100 μm, and the film was heated at 130°C for 5 minutes. This produced a sheet material with a thickness of 45 to 55 μm on the support sheet.

[0163] The sheet material was placed on top of the semiconductor wafer, and then fixed to a dicing frame. The sheet material was diced together with the silicon wafer using a DISCO dicing saw (product name: DFD6341), to cut out chip components measuring 7.3 mm x 7.3 mm x 100 μm, each comprising a semiconductor chip and an individual sheet containing sealing material.

[0164] A Panasonic FCB3 flip chip bonder with ultrasonic vibration capability was used. The stage of the flip chip bonder was heated, and the substrate was fixed on the stage. The chip component was held by the bonding head of the flip chip bonder. While the bonding head was heated, the bonding head was brought close to the stage, aligning the bump electrodes of the semiconductor chip with the conductive wiring of the substrate. The chip component was then stacked on the substrate. The stage temperature was set to 120°C, and the bonding head temperature to 200°C, ensuring that the heating temperature of the encapsulating resin composition reached 200°C. In this state, the semiconductor chip was pressed with the flip chip bonder, and ultrasonic vibrations were applied while applying a load to the semiconductor chip toward the substrate. The pressure was 10 N for 0.1 seconds from the start of pressure application, then increased to 90 N at 0.1 seconds, and maintained at 90 N from 0.2 seconds after the start of pressure application until 1.0 seconds had elapsed. The ultrasonic vibration was applied 0.5 seconds after the start of pressure application, with the output reaching 3 W at 0.6 seconds. The ultrasonic vibration output was maintained at 3 W from 0.6 seconds to 1.0 seconds after the start of pressure application. After 1.0 seconds had elapsed since the start of pressure application, the pressure was released and the bonding head was removed from the stage. The sealing material between the substrate and the semiconductor chip was then completely cured by heating (after-curing) at 175°C for 4 hours. This resulted in a semiconductor device for testing before reflow. Note that in Comparative Example 4, mounting was not possible using the above method, and a semiconductor device could not be fabricated. Therefore, evaluations from (3-3) below were not performed.

[0165] (3) Evaluation test The encapsulating resin composition and the semiconductor device provided with the encapsulating material produced using the encapsulating resin composition were subjected to the following evaluation tests. The results of these evaluation tests are shown in Table 1.

[0166] (3-1) Minimum melt viscosity The temperature dependence of melt viscosity of each of the encapsulating resin compositions of the Examples and Comparative Examples prepared in (1) above was measured using a rheometer (model AR2000ex) manufactured by TA Instruments Inc. under conditions of a temperature range of 40 to 200°C, a heating rate of 6°C / min, and an angular velocity of 6.283 rad / s. A melt viscosity curve showing the relationship between the temperature and melt viscosity of the encapsulating resin composition was obtained. The minimum melt viscosity was read from this melt viscosity curve, and the value is shown in Table 1.

[0167] (3-2) Void The semiconductor device before reflow manufactured in (2) above was inspected for voids in the encapsulant of this semiconductor device using an ultrasonic flaw detector (SAT: Scanning Acoustic Tomography) and voids were confirmed within an area of ​​3 mm × 4 mm. The results were evaluated according to the following criteria. A: No voids of 20 μm or larger were observed. B: There were less than 10 voids of 20 μm or larger, and no voids of 40 μm or larger were observed. C: A large number of voids of 40 μm or more were observed.

[0168] (3-3) Connectivity during implementation In the above (2), the semiconductor device after applying ultrasonic vibration and pressure (i.e., the semiconductor device before after-cure) was taken out, and the connection resistance value was checked using a digital multimeter (PC500) manufactured by Sanwa Electric Instruments Co., Ltd. The results were evaluated according to the following criteria. A: The connection resistance is 20 Ω or less. B: The connection resistance is greater than 20 Ω and less than 50 Ω. C: Connection resistance cannot be measured.

[0169] (3-4) Connectivity after reflow After reflowing the semiconductor device samples of (3-3) above, the connection resistance values ​​were checked and evaluated in the same manner as in (3-3).

[0170] [Table 1] [Explanation of symbols]

[0171] 1. Semiconductor device 2 Base material 21 Conductor wiring 3. Semiconductor chips 32 solder bumps 4. Encapsulating material

Claims

1. An encapsulating resin composition used to seal a gap between a substrate and a semiconductor chip mounted on the substrate, The composition contains a radical polymerizable monomer (A) and a thermoplastic elastomer (B), a mass ratio of the thermoplastic elastomer (B) to the total amount of the encapsulating resin composition is 3 mass% or more and 19 mass% or less, The minimum melt viscosity at 60°C or higher and 180°C or lower is 500 Pa s or higher and 5000 Pa s or lower. Sealing resin composition.

2. sealing the gap between the substrate and the semiconductor chip includes applying ultrasonic vibration to the solder bumps while heating the solder bumps and the encapsulating resin composition in a state where the solder bumps and the encapsulating resin composition are interposed between the substrate and the semiconductor chip; The encapsulating resin composition according to claim 1 .

3. a mass ratio of the radical polymerizable monomer (A) to the total solid content of the encapsulating resin composition is 1 mass% or more and 22 mass% or less; The encapsulating resin composition according to claim 1 .

4. The melt mass flow rate (MFR) of the thermoplastic elastomer (B) measured under conditions of a heating temperature of 230°C and a load of 21 N is 1.8 g / 10 min or more and 13.5 g / 10 min or less. The encapsulating resin composition according to claim 1 .

5. a mass ratio of the radical polymerizable monomer (A) to the total amount of the radical polymerizable monomer (A) and the thermoplastic elastomer (B) is 5 mass% or more and 85 mass% or less; The encapsulating resin composition according to claim 1 .

6. Further containing an epoxy compound (C), The encapsulating resin composition according to claim 1 .

7. Further containing an inorganic filler (D), The mass ratio of the inorganic filler (D) to the total amount of the encapsulating resin composition is 50 mass% or more and 65 mass% or less. The encapsulating resin composition according to claim 1 .

8. Further containing a polymerization initiator (E), The encapsulating resin composition according to claim 1 .

9. Further containing a flux, The encapsulating resin composition according to claim 1 .

10. A substrate; a semiconductor chip mounted face down on the substrate; a sealing material that seals a gap between the base material and the semiconductor chip, The encapsulant comprises a cured product of the encapsulating resin composition according to claim 1. Semiconductor device.

11. A method for manufacturing a semiconductor device including a base material, a semiconductor chip mounted on the base material, and a sealing material that seals a gap between the base material and the semiconductor chip, The method comprises: applying ultrasonic vibration to the solder bumps while heating the solder bumps and the encapsulating resin composition according to claim 1 in a state where the solder bumps and the encapsulating resin composition are interposed between the substrate and the semiconductor chip. A method for manufacturing a semiconductor device.

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