Method for manufacturing an electronic device, and electronic device

Abstract

Provided is an electronic device manufacturing method by which a void is less likely to occur in a sealing material even when a gap between electrodes of a mounting component of the electronic device and a gap between a base material and the mounting component are reduced. The electronic device (1) manufacturing method comprises a mounting step, an injection step, and a sealing step. In the mounting step, a mounting component (3) is surface-mounted on a base material (2) via a plurality of electrodes (33). In the injection step, a thermosetting sealing resin composition is injected between the base material (2) and the mounting component (3). In the sealing step, the sealing resin component is cured to produce a sealing material (4). In the sealing step, the sealing resin composition is heated under pressure and thus cured. The shortest pitch between the plurality of electrodes (33) is 100 μm or less, and a gap between the base material (2) and the mounting component (3) is 25 μm or less.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing an electronic device and an electronic device. Specifically, the present disclosure relates to a method for manufacturing an electronic device including a base material, a mounted component, and a sealing material interposed in a gap between the base material and the mounted component, and an electronic device including a sealing material made from a resin composition for sealing.

Background Art

[0002] Patent Document 1 discloses an underfill material containing an epoxy compound, an epoxy curing agent, and a curing accelerator. By including an imidazole and a phosphonium salt, the curing accelerator controls the reactivity of the underfill material while maintaining the viscosity, thereby curing the underfill material to seal the gap between the base material and the mounted component in an electronic device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] An object of the present disclosure is to provide a method for manufacturing an electronic device and an electronic device in which voids are less likely to occur in a sealing material even when the distance between electrodes of a mounted component and the distance between the base material and the mounted component are reduced in the electronic device.

[0005] The manufacturing method of an electronic device according to one aspect of the present disclosure includes a mounting step, an injection step, and a sealing step. In the mounting step, a mounting component is surface-mounted on a substrate via a plurality of electrodes. In the injection step, a thermosetting resin composition for sealing is injected between the substrate and the mounting component. In the sealing step, the resin composition for sealing is cured to produce a sealing material. The shortest pitch between the plurality of electrodes is 100 μm or less, and the distance between the substrate and the mounting component is 25 μm or less. In the sealing step, the resin composition for sealing is cured by heating under pressure.

[0006] An electronic device according to one aspect of the present disclosure is manufactured by the manufacturing method of the electronic device.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0008] 1. Overview First, the background leading to the invention according to the present disclosure will be described.

[0009] Conventionally, a sealing material in an electronic device is sometimes produced by a so-called underfill method in which a mounting component having electrodes such as a semiconductor element on a substrate is stacked by flip chip, and then a liquid sealing material (underfill material) for producing a sealing material is injected and filled into the gap between the substrate and the mounting component.

[0010] In the underfill method, by filling the underfill material as described above and then curing it, the gap between the substrate and the mounting component can be sealed with a cured product of the underfill material. Therefore, it is widely used as a method for producing a sealing material in an electronic device.

[0011] In recent years, with the improvement of the performance of electronic devices, miniaturization of electronic devices (hereinafter also referred to as fining) has been required. That is, in electronic devices, the substrate and mounted components are miniaturized, and fining such as reduction in the distance between the substrate and the mounted components and reduction in the distance between the electrodes of the mounted components (sometimes referred to as narrow gap / pitch) and fining of the gap (narrow gap) are being carried out.

[0012] By the way, when injecting an underfill material into the gap between the base material and the mounted component in an electronic device to seal the gap, there is a problem that voids are likely to occur in the underfill material as the electronic device is fined. Therefore, in manufacturing a fined electronic device, in order to ensure the connection reliability of the electronic device, it is required to suppress the generation of voids in the sealing material when manufacturing the sealing material for sealing the gap between the base material and the mounted component.

[0013] However, in order to manufacture an electronic device aimed at improving performance by miniaturizing the distance (also referred to as gap) between the base material and the mounted component and the distance (also referred to as pitch) between the electrodes of the mounted component in the electronic device, it was difficult to sufficiently fill the gap only by filling with a sealing material and then heating and curing it. Also, in this case, it was found that voids remained in the sealing material. The inventors have found that this is partly because when the electronic device is fined, in the conventional manufacturing method, the sealing material hardly flows sufficiently in the gap between the base material and the mounted component, and even if it can flow, voids are likely to occur in the sealing material before curing.

[0014] Therefore, the inventors have conducted intensive research to solve the above problems, and have found the conditions for manufacturing an electronic device for manufacturing a fined electronic device, the composition of a sealing resin composition for manufacturing a sealing material in the fined electronic device, and the physical properties.

[0015] FIG. 1 is a schematic cross-sectional view showing an electronic device according to an embodiment of the present disclosure. The manufacturing method of the electronic device 1 of the present embodiment includes a mounting step, an injection step, and a sealing step. In the mounting step, the mounting component 3 is surface-mounted on the base material 2 via a plurality of electrodes 33. In the injection step, a thermosetting resin composition for sealing is injected between the base material 2 and the mounting component 3. In the sealing step, the resin composition for sealing is cured to produce a sealing material 4. The shortest pitch between the plurality of electrodes 33 is 100 μm or less, and the distance between the base material 2 and the mounting component 3 is 25 μm or less. In the sealing step, the resin composition for sealing is cured by heating under pressure. According to the present embodiment, by injecting the resin composition for sealing into the gap between the base material 2 and the mounting component 3 and heating under pressure, even if voids that cause voids are generated in the resin composition for sealing during injection, the voids can be crushed or discharged to the outside before the resin composition for sealing cures. Therefore, even when the distance between the electrodes 33 of the mounting component 3 in the electronic device 1 and the distance between the base material 2 and the mounting component 3 are narrowed, voids are less likely to occur in the sealing material 4.

[0016] In addition, the inventors have also found a resin composition for sealing that is suitable for producing the sealing material 4 in the miniaturized electronic device 1 by heating under pressure to cause thermosetting. That is, the resin composition for sealing in the present embodiment is a thermosetting resin composition for producing the sealing material 4 that seals the gap between the base material 2 and the mounted component 3 mounted on the base material 2. The viscosity of the resin composition for sealing at 100°C is 0.15 Pa·s or less. Therefore, when producing the sealing material 4 from the resin composition for sealing, it can have appropriate fluidity when injecting the resin composition for sealing, and can be sufficiently filled in the gap between the base material 2 and the mounted component 3. Thereby, when producing the miniaturized electronic device 1, by interposing the resin composition for sealing between the base material 2 and the mounted component 3 and heating under pressure, voids are less likely to occur in the sealing material 4. In the present embodiment, the miniaturized electronic device 1 refers to one having a shortest pitch of 100 μm or less and a gap of 25 μm or less. The pitch refers to the dimension between a plurality of electrodes in the mounted component 3, and the gap refers to the distance between the base material 2 and the mounted component 3. However, the resin composition for sealing in the present embodiment is not limited to being used only for producing the above-described miniaturized electronic device 1. For example, the resin composition for sealing according to the present embodiment can be applied regardless of the pitch interval and the gap interval.

[0017] Thus, in the present embodiment, the resin composition for sealing is interposed in the gap between the base material 2 and the mounted component 3, and the sealing material 4 can be produced from the resin composition for sealing by heating and pressurizing. Even when the resin composition for sealing is made to flow, voids are less likely to occur in the resin composition for sealing. As a result, voids in the sealing material 4 in the electronic device 1 can be reduced. Thereby, the connection reliability in the electronic device 1 can be ensured.

[0018] 2. Details Hereinafter, details of the resin composition for sealing and the electronic device 1 in the present embodiment will be described. In this specification, the expression "A and / or B" means any one of "A", "B", or "A and B".

[0019] <Resin composition for sealing> First, the preferable properties (physical properties) of the resin composition for sealing will be described.

[0020] The viscosity of the resin composition for sealing in this embodiment at 100°C is 0.15 Pa·s or less. In this case, for example, when applying the resin composition for sealing, more uniform fillability and good filling speed under the mounting component 3 can be achieved. Thereby, when producing the sealing material 4 from the resin composition for sealing by heating under pressure, it is possible to make it less likely to generate voids in the sealing material 4. The resin composition for sealing is more preferably 0.10 Pa·s or less, and even more preferably 0.08 Pa·s or less when heated to 100°C. Note that the viscosity of the resin composition for sealing at 100°C is obtained by measuring using a rheometer under the condition of a rotation speed of 1 rpm.

[0021] When the resin composition for sealing of the present embodiment is heated under at least one heating condition with a temperature rising rate of 0.5°C / min to 50°C / min from 25°C, it is preferable that the viscosity at the time of reaching the curing temperature is 0.150 Pa·s or less. The "curing temperature" in the present embodiment refers to the temperature at the time when the initial viscosity reaches 100 times or more within 2 hours from the start of heating. The curing temperature can be obtained by applying the resin composition for sealing on the stage of a rheometer with the rheometer, heating the stage at a temperature within the range of 80°C to 150°C, and then measuring the viscosity of the resin composition for sealing after 2 hours under the condition of a rotation speed of 1 rpm. Also, the "viscosity at the time of reaching the curing temperature" of the resin composition for sealing can be obtained by using a rheometer, allowing the resin composition for sealing to stand on a stage that has been previously heated to a temperature within the range of 80°C to 150°C, and measuring under the condition of a rotation speed of 1 rpm. The curing temperature varies depending on the components constituting the resin composition for sealing, the blending ratio of the components, the mixing method when preparing the composition, etc. In the present embodiment, however, by adjusting the composition components and / or the composition ratio, it is possible to control the viscosity at the time of reaching the curing temperature of the resin composition for sealing to be 0.150 Pa·s or less. The viscosity when heated to the curing temperature is more preferably 0.10 Pa·s or less, and even more preferably 0.08 Pa·s or less.

[0022] The viscosity of the resin composition for sealing at 25°C is preferably less than 0.05 Pa·s. In this case, when molding the resin composition for sealing, even at a temperature near room temperature (25°C), that is, even without previously heating the resin composition for sealing, for example, the coating workability and discharge stability by jet dispensing can be improved. Also, in this case, good fillability under the mounting component 3 such as a semiconductor element can be achieved. The viscosity of the resin composition for sealing at 25°C is more preferably 0.04 Pa·s or less, and even more preferably 0.03 Pa·s or less. The lower limit of the viscosity of the resin composition for sealing at 25°C is not particularly limited, but it may be, for example, 0.01 Pa·s or more.

[0023] The resin composition for sealing preferably has foamability. Here, the "foamability" in the present disclosure can be confirmed as follows. First, prepare an appropriate container having a bottom area of 450 mm 2 and a height of 55 mm or more, and put the resin composition for sealing into the container so that the height from the bottom surface of the container is 20 mm. Subsequently, the inside of the container is depressurized at a temperature of 25°C and 200 Pa / 10 min. After 10 minutes have elapsed since the start of depressurization, check the inside of the container, and by observing whether the resin composition for sealing is ejected (foamed) due to depressurization, check whether there is adhesion of the resin composition for sealing to the wall surface of the container. Then, if the height of the deposit from the bottom surface of the container on the wall surface of the container is 40 mm or less, it can be said that it has excellent foamability. When the resin composition for sealing has foamability, in the electronic device 1, even if the distance between the electrodes of the mounted component and the distance between the base material and the mounted component are narrowed, when a sealing material is produced from the resin composition for sealing by an underfill method, generation of voids in the sealing material 4 is particularly unlikely to occur. In the above, the height of the deposit on the wall surface is more preferably 35 mm or less, still more preferably 30 mm or less, and particularly preferably if there is no ejection of the resin composition for sealing and no deposit on the wall surface (that is, if it is substantially 0 mm).

[0024] The preferable characteristics of the above-described resin composition for sealing can be more specifically realized by appropriately adjusting the components of the composition described below. However, the physical properties of the resin composition for sealing are not limited only to the physical properties described above.

[0025] As shown in Fig. 1, the resin composition for sealing according to this embodiment can be suitably used as a sealing material 4 for sealing between a base material 2 and a mounted component 3 in an electronic device 1. For example, the resin composition for sealing may be a sealing material 40, and specifically, it can be suitably used as an underfill material. When the resin composition for sealing is used as a sealing material (underfill material) to produce the sealing material 4 from the resin composition for sealing, voids are less likely to occur in the sealing material 4. In particular, the resin composition for sealing of this embodiment is suitably used for producing a sealing material 4 in the electronic device 1 when producing an electronic device 1 in which the shortest pitch between a plurality of electrodes is 100 μm or less and the distance between the base material 2 and the mounted component 3 is 25 μm or less.

[0026] Next, the components that can be included in the resin composition for sealing will be described in detail.

[0027] [Epoxy resin] In this embodiment, the resin composition for sealing contains an epoxy resin (A). In this embodiment, the epoxy resin (A) is a thermosetting component.

[0028] The epoxy resin (A) includes a bisphenol type epoxy resin (A1) and an aromatic amino epoxy resin (A2). That is, it is preferable that the resin composition for sealing contains at least one or both of the bisphenol type epoxy resin (A1) and the aromatic amino epoxy resin (A2).

[0029] The bisphenol type epoxy resin (A1) contains at least one selected from the group consisting of, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and derivatives of these resins. The bisphenol type epoxy resin (A1) preferably contains a bisphenol F type epoxy resin in particular. In this case, better thermosetting properties can be imparted to the encapsulating resin composition. The bisphenol F type epoxy resin is a compound in which two phenol skeletons are bonded via one methylene chain. The bisphenol F type epoxy resin may have a substituent in the phenol skeleton.

[0030] The viscosity of the bisphenol type epoxy resin (A1) at 100 °C is preferably, for example, 0.01 Pa·s or more and 0.50 Pa·s or less.

[0031] The aromatic amino epoxy resin (A2) can impart better thermosetting properties to the encapsulating resin composition while maintaining the storage stability of the encapsulating resin composition.

[0032] The aromatic amino epoxy resin (A2) preferably has an aromatic ring, an amino group bonded to the aromatic ring, and three or more epoxy groups in one molecule. That is, the aromatic amino epoxy resin (A2) is preferably trifunctional or higher.

[0033] More preferably, the aromatic amino epoxy resin (A2) includes an aromatic ring, an amino group bonded to the aromatic ring, an epoxy group bonded to the amino group, and an epoxy group bonded at a position different from the amino group bonded to the aromatic ring. That is, when the aromatic amino epoxy resin (A2) has three or more epoxy groups, at least one of them is preferably bonded to the amino group bonded to the aromatic ring.

[0034] Specific examples of the aromatic amino epoxy resin (A2) include, for example, N,N-diglycidyl-p-glycidyloxyaniline and the like. Note that the aromatic amino epoxy resin (A2) is not limited to the above compounds.

[0035] The viscosity of the aromatic amino epoxy resin (A2) at 100°C is preferably 0.01 Pa·s or more and 0.50 Pa·s or less.

[0036] More preferably, the resin composition for sealing contains both the above-mentioned bisphenol type epoxy resin (A1) and aromatic amino epoxy resin (A2). In this case, it is easy to make the appropriate curing reaction of the components in the resin composition for sealing proceed. Therefore, it is easy to satisfactorily seal the gap between the base material 2 and the mounted component 3 with the sealing material made from the resin composition for sealing.

[0037] When the resin composition for sealing contains bisphenol type epoxy resin (A1) and aromatic amino epoxy resin (A2), the mass ratio of the total amount of bisphenol type epoxy resin (A1) and aromatic amino epoxy resin (A2) to the epoxy resin (A) is preferably 30% by mass or more and 70% by mass or less.

[0038] When the resin composition for sealing contains bisphenol type epoxy resin (A1) and aromatic amino epoxy resin (A2), the total content of bisphenol type epoxy resin (A1) and aromatic amino epoxy resin (A2) with respect to the total amount of the resin composition for sealing is preferably 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 35% by mass or less, and still more preferably 20% by mass or more and 30% by mass or less. Within this range, it is easier to maintain better fluidity of the resin composition for sealing and it can be satisfactorily filled in the gap between the base material 2 and the mounted component 3. Therefore, the gap between the base material 2 and the mounted component 3 can be sufficiently sealed, and it is possible to make the sealing material 4 made from the resin composition for sealing less likely to generate voids.

[0039] The components that can be contained in the epoxy resin (A) in the resin composition for sealing are not limited to those described above, and may contain resins having an epoxy group other than the above.

[0040] The resin composition for sealing preferably further contains phosphoric acid (B) and phosphoric acid polyester (C).

[0041] [Phosphoric acid (B)] Phosphoric acid (B) has a structure represented by the following formula (1).

[0042] [Chemical formula]

[0043] When the resin composition for sealing contains phosphoric acid (B), the effect of improving the dispersibility in the resin composition for sealing by the phosphoric acid polyester (C) described later can be promoted. It is preferable that phosphoric acid (B) is blended in the resin composition for sealing with a mixture prepared by mixing with phosphoric acid polyester (C).

[0044] [Phosphoric acid polyester (C)] The resin composition for sealing preferably contains phosphoric acid polyester (C). When the resin composition for sealing contains phosphoric acid polyester (C), it is easy to enhance the dispersibility of the components contained in the resin composition for sealing.

[0045] Furthermore, when the resin composition for sealing contains phosphoric acid polyester (C), it is difficult to inhibit the effect of reducing the CTE of the cured product produced from the resin composition for sealing. That is, the coefficient of thermal expansion of the cured product of the resin composition for sealing can be kept low. Note that CTE means Coefficient of Thermal Expansion, and may also be referred to as "coefficient of thermal expansion" or "linear expansion coefficient" hereinafter.

[0046] When the resin composition for sealing contains phosphoric acid (B) and phosphoric acid polyester (C), even if the ratio of the inorganic filler (filler) (D) described later is increased, it is difficult to reduce the dispersibility of the filler. Therefore, the ratio of the filler (D) in the resin composition for sealing can be easily increased, and it is easier to achieve a lower CTE of the cured product produced from the resin composition for sealing.

[0047] Phosphoric acid polyester (C) may have a structure represented by the following formula (2).

[0048]

Chem.

[0049] In formula (2), R1, R2, and R3 are each independently a substituent selected from the group consisting of, for example, an alkyl group, an alkenyl group, and an alkynyl group. R1, R2, and R3 may each independently be long-chain or branched. Note that at least one of R1, R2, and R3 may be a hydrogen atom. That is, the phosphate polyester (C) is a compound in which at least two hydrogen atoms in formula (1) of the phosphoric acid (B) are each independently substituted with R1, R2, and R3.

[0050] In formula (2), at least one of R1, R2, and R3 may be a substituent having a polyester structure. That is, when one of R1, R2, and R3 is a substituent having a polyester structure, the others may be at least one selected from a hydrogen atom, an alkyl group, an alkenyl group, an aralkyl group, an aryl group, and a polyoxyalkylene group. Further, when two of R1, R2, and R3 are substituents having a polyester structure, the others may be at least one selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, an aralkyl group, an aryl group, and a polyoxyalkylene group. When R1, R2, and R3 are all substituents having a polyester structure, the substituents having a polyester structure may all have the same polyester structure or may each independently have a different polyester structure. Note that the polyester structure includes a polymer having an ester group obtained from a dicarboxylic acid and a diol, a polymer having an ester group obtained by polycondensation of a hydroxycarboxylic acid, and a polymer obtained by ring-opening polymerization of a cyclic ester compound such as a lactone.

[0051] The substituents R1, R2, and R3 may contain a phosphorus atom. For example, the phosphoric acid polyester (C) may be a compound derived from a polyphosphoric acid represented by the following formula (3). That is, the phosphoric acid polyester (C) may have two or more phosphorus atoms in one molecule.

[0052]

Chemical formula

[0053] In formula (3), n is 2 or more. When the phosphoric acid polyester (C) is derived from formula (3), at least two of the hydrogen atoms in formula (3) may be substituted with a group selected from the group consisting of an alkyl group, an alkenyl group, and an alkynyl group. Further, the phosphoric acid polyester (C) may have a hydroxy group at the terminal. When n = 1, it corresponds to the phosphoric acid (B) represented by formula (1).

[0054] The phosphoric acid polyester (C) is not limited to the above, and may include, for example, a reaction product obtained by reacting an appropriate alkyl ether, polyalkylene glycol monoalkyl ether, etc. with a phosphoric acid esterifying agent.

[0055] Examples of specific products of the phosphoric acid polyester (C) include phosphoric acid polyesters that may be contained in, for example, the BYK-W series (such as BYK-W9010, etc.) and the DISPERBYK series (such as DISPERBYK-111, etc.) manufactured by Big Chemie Japan Co., Ltd.

[0056] The mass ratio of the phosphoric acid polyester (C) to the total amount of the resin composition for sealing is preferably more than 0% by mass and less than 100% by mass, more preferably 0.01% by mass or more and 90% by mass or less, still more preferably 0.02% by mass or more and 50% by mass or less, and particularly preferably 0.05% by mass or more and less than 10% by mass.

[0057] In addition, when the resin composition for sealing contains both phosphoric acid (B) and a phosphoric acid polyester (C), the dispersibility of the components in the resin composition for sealing can be further improved. Therefore, since the dispersibility of the resin composition for sealing is higher, good fluidity can be maintained. As a result, it is easy to flow the resin composition for sealing in the gap between the base material 2 and the mounted component 3, and thus it is easy to sufficiently fill the gap with the sealing material 4.

[0058] When the resin composition for sealing contains silica (D1) described later, the total mass ratio of phosphoric acid (B) and the phosphoric acid polyester (C) to silica (D1) is preferably 0.05% by mass or more and 1.0% by mass or less. In this case, the CTE of the cured product of the resin composition for sealing can be further reduced. The mass ratio of the phosphoric acid polyester (C) is more preferably 0.1% by mass or more and 0.5% by mass or less, and even more preferably 0.2% by mass or more and 0.4% by mass or less. In this case, good fluidity can be imparted to the resin composition for sealing, and thus it is easier to further fill the gap with the resin composition for sealing.

[0059] [Inorganic filler (D)] The resin composition for sealing preferably contains an inorganic filler (D). The inorganic filler (D) can contribute to the reduction of the linear expansion coefficient of the cured product produced from the resin composition for sealing. Further, when the resin composition for sealing contains the above-mentioned phosphoric acid (B) and the phosphoric acid polyester (C), even if it contains the inorganic filler (D), it is difficult to reduce the dispersibility of the resin composition for sealing. For this reason, an excessive increase in the viscosity of the resin composition for sealing hardly occurs, the fluidity can be maintained, and the thixotropy is hardly deteriorated. As a result, even if the content of the inorganic filler (D) is increased, the resin composition for sealing hardly deteriorates in fluidity, and the linear expansion coefficient of the resin composition for sealing can be lowered.

[0060] The inorganic filler (D) preferably contains silica (D1), and it is also preferable that at least a part of the silica (D1) is surface-treated with a coupling agent. In this case, the compatibility between the epoxy resin (A) and the silica (D1) in the encapsulating resin composition can be improved, and it can further contribute to the improvement of the dispersibility of the encapsulating resin composition. Also, in this case, the viscosity of the encapsulating resin composition when heated to 100 °C can be easily lowered. The coupling agent is, for example, a silane coupling agent. Examples of the silane coupling agent include compounds having at least one functional group selected from the group consisting of an epoxy group, an amino group, a (meth)acryloyl group, and a phenyl group. The silane coupling agent is preferably a silane coupling agent having a phenyl group. That is, it is preferable that at least a part of the silica (D1) is surface-treated with a silane coupling agent having a phenyl group. In this case, the dispersibility of the encapsulating resin composition can be further improved.

[0061] When the inorganic filler (D) contains silica (D1), the silica (D1) preferably includes a first silica filler (D11) and a second silica filler (D12) having an average particle size different from that of the first silica filler (D11). The "average particle size" in the present disclosure is the volume average diameter. The volume average diameter is calculated from the particle size distribution obtained by measurement by the laser diffraction / scattering method. The particle size distribution can be measured, for example, by a laser diffraction type particle size distribution measuring device, and examples of the laser diffraction type particle size distribution measuring device include the LA-960 series manufactured by Horiba, Ltd.

[0062] The average particle size of the first silica filler (D11) is preferably 0.1 μm or more and 1.5 μm or less, and the standard deviation in the particle size distribution of the first silica filler (D11) in this case is preferably 0.01 or more and less than 1.0. Further, the average particle size of the second silica filler (D12) is 10% or more and 50% or less with respect to the average particle size of the first silica filler (D11), and it is preferable that the standard deviation in the particle size distribution of the second silica filler (D12) is 0.01 or more and less than 1.0. Here, the "standard deviation in the particle size distribution" in the present disclosure is an index indicating the width of the particle size distribution. Whether the particle sizes of the particles are uniform can be determined by the standard deviation in the particle size distribution. The standard deviation in the particle size distribution can be calculated as follows. Similar to the above average particle size (volume average diameter), in the particle size distribution obtained by measurement using the laser diffraction / scattering method, the standard deviation can be calculated from the particle size data of each particle and the average particle size. When the silica particles in each of the first silica filler (D11) and the second silica filler (D12) among the silica (D1) in the encapsulating resin composition have a standard deviation in the particle size distribution of 0.01 or more and less than 1.0, the viscosity of the encapsulating resin composition can be further reduced. Thereby, the encapsulating resin composition can ensure fluidity. For this reason, when using the encapsulating resin composition to encapsulate the gap between the substrate and the semiconductor element, better moldability can be achieved.

[0063] The average particle size of the first silica filler (D11) is more preferably 0.1 μm or more and 1.0 μm or less. Further, the standard deviation in the particle size distribution of the first silica filler (D11) is preferably 0.01 or more and 0.60 or less, more preferably 0.02 or more and 0.40 or less, still more preferably 0.02 or more and 0.36 or less, and particularly preferably 0.05 or more and 0.36 or less. The average particle size of the second silica filler (D12) is not particularly limited as long as it satisfies the above, but the average particle size of the second silica filler (D12) can be, for example, 0.01 μm or more and 0.75 μm or less. The standard deviation in the particle size distribution of the second silica filler (D12) is preferably 0.01 or more and less than 0.10, more preferably 0.02 or more and 0.08 or less, still more preferably 0.03 or more and 0.08 or less, and particularly preferably 0.04 or more and 0.06 or less.

[0064] Each of the first silica filler (D11) and the second silica filler (D12) is preferably wet silica. Wet silica is amorphous silica synthesized in a liquid, and for example, wet silica can be produced by at least one method selected from the group consisting of the precipitation method and the sol-gel method. Wet silica is particularly preferably produced by the sol-gel method. In this case, the average particle size of the wet silica particles can be kept relatively small, such as 0.1 μm or more and 1.5 μm or less, and the variation in the particle size distribution can be made less likely to occur. That is, in this case, it is easy to make the particle sizes of the first silica filler (D11) and the second silica filler (D12) uniform. The sol-gel method is a synthetic method for obtaining a solid substance through a gel state in which fluidity is lost from a sol state in which fine particles such as colloids are dispersed in a solution, and an appropriate method may be adopted as the synthetic method. Whether the first silica filler (D11) of the present disclosure is produced by the sol-gel method can be confirmed by appropriately cutting the particles of the first silica filler (D11) and observing the cross section thereof. Specifically, for example, a cured product of the resin composition for sealing is cut, the cut surface is observed with an electron microscope or the like, and the particle size of silica on the cut surface is measured, whereby it can be determined that it is produced by the sol-gel method. Whether the second silica filler (D12) and the third silica filler (D13) described later are produced by the sol-gel method can also be confirmed in the same manner as the first silica filler (D11).

[0065] Silica (D1) is the first silica filler (D11) and the second silica filler ( DIt is also preferable to further include a third silica filler (D13) having an average particle size different from any of those in (12). That is, it is also preferable that the resin composition for sealing contains a first silica filler (D11), a second silica filler (D12), and a third silica filler (D13). When silica (D1) contains the third silica filler (D13), the average particle size of the third silica filler (D13) is not particularly limited as long as it is smaller than the average particle size of the second silica filler (D12). The standard deviation in the particle size distribution of the third silica filler (D13) is preferably 0.01 or more and less than 0.10, more preferably 0.02 or more and 0.09 or less, still more preferably 0.03 or more and 0.08 or less, and particularly preferably 0.04 or more and 0.06 or less. When the resin composition for sealing contains the third silica filler (D13), the resin composition for sealing can particularly lower the fluidity, and even if the fluidity of the resin composition for sealing is lowered, it can have good thixotropy. The mass ratio of the third silica filler (D13) is preferably 5% by mass or more and 40% by mass or less based on the total amount of silica (D1). If the mass ratio of the third silica filler (D13) based on the total amount of silica (D1) is 5% by mass or more, the thixotropy can be made better, and if it is 40% by mass or less, good fluidity can be maintained.

[0066] When silica (D1) contains the third silica filler (D13), the third silica (D13) is also preferably wet silica. In this case, the third silica filler (D13) is also preferably wet silica produced by the sol-gel method. In this case, it is easy to adjust each of the first silica filler (D11), the second silica filler (D12), and the third silica filler (D13) to be silica particles with uniform particle sizes.

[0067] The first silica filler (D11) may be surface-treated with a coupling agent. The surface treatment of the silica filler can be achieved, for example, by reacting a coupling agent (such as a silane coupling agent) with wet silica prepared by the sol-gel method. Similarly, the second silica filler (D12) and the third silica filler (D13) may also be surface-treated with a coupling agent.

[0068] The mass ratio of the first silica filler (D11) to the second silica filler (D12) in the silica (D1) is preferably in the range of 60:40 to 98:2. When the silica (D1) further contains the third silica filler (D13), the mass ratio of the first silica filler (D11), the second silica filler (D12), and the third silica filler (D13) is preferably in the range of 60:30:10 to 90:8:2.

[0069] When containing the inorganic filler (D), the content of the inorganic filler (D) with respect to the total amount of the resin composition for sealing is preferably 50% by mass or more and 75% by mass or less. In this case, it becomes possible to further lower the CTE of the resin composition for sealing. In the present embodiment, even if the proportion of the inorganic filler (D) is relatively increased, the fluidity of the resin composition for sealing can be maintained particularly well. Therefore, it is possible to hardly cause unfilling into the gaps of the resin composition for sealing. The content of the inorganic filler (D) is more preferably 50% by mass or more and 70% by mass or less, and still more preferably 55% by mass or more and 65% by mass or less.

[0070] The inorganic filler (D) may contain fillers other than silica as long as the effects of the present disclosure are not inhibited.

[0071] The resin composition for sealing may contain other appropriate compounds, resins, additives, etc. In the present embodiment, the preferred components of the additives that the resin composition for sealing may contain will be described more specifically.

[0072] [Defoaming agent (E)] The resin composition for sealing preferably further contains an antifoaming agent (E). The antifoaming agent (E) can have a function of suppressing foaming in the resin composition for sealing (antifoaming function). Bubbles (air bubbles) can be formed when the components contained in the resin composition for sealing are mixed and prepared, by the liquid enclosing air. As a result, air bubbles may be enclosed in the resin composition for sealing, which may contribute to the formation of voids in the sealing material. When the resin composition for sealing contains the antifoaming agent (E), foaming of the resin composition for sealing can be suppressed by defoaming, foam suppression, or degassing the formed bubbles when preparing the resin composition for sealing. Therefore, when producing a sealing material from the resin composition for sealing, it is possible to make it less likely for further voids to occur in the sealing material.

[0073] Examples of specific products of the antifoaming agent (E) include BYK1799, etc. manufactured by Big Chemie Japan Co., Ltd. Note that the examples of the antifoaming agent (E) are not limited to the above.

[0074] [Surface conditioner (F)] The resin composition for sealing preferably further contains a surface conditioner (F). The surface conditioner (F) can have a function of adjusting the surface tension of the resin composition for sealing. When the resin composition for sealing contains the surface conditioner (F), it is easy to adjust the viscosity of the resin composition for sealing during heating. In particular, in this embodiment, the surface conditioner (F) can further lower the viscosity when the resin composition for sealing is heated to 100°C. For this reason, the fluidity when filling between the base material 2 and the mounted component 3 to produce a sealing material from the resin composition for sealing can be made even better. Also, the surface conditioner (F) may have an antifoaming function similar to the above-mentioned antifoaming agent (E).

[0075] Examples of the surface conditioner (F) include polyether-modified polydimethylsiloxane, acrylic copolymers, etc. Examples of specific commercially available products of the surface conditioner (F) include BYK-306, BYK-3441, etc. manufactured by Big Chemie Japan Co., Ltd.

[0076] [Curing aid (G)] The resin composition for sealing preferably contains a curing aid (G). In this case, it can contribute to the storage stability of the resin composition for sealing. Also, in this case, when curing the resin composition for sealing, the rate of the curing reaction can be controlled. Note that the curing aid (G) includes a curing accelerator. The curing aid (G) has a function of promoting the progress of the reaction of the curable components in the resin composition for sealing. In the present embodiment, the curing aid (G) can suppress the excessive progress of the curing reaction when curing the epoxy resin (A) in the resin composition for sealing. In other words, the curing aid (G) is less likely to excessively increase the reactivity of the curing of the resin composition for sealing and can cause the curing to proceed at a good curing rate. For this reason, even if the resin composition for sealing starts to cure due to a temperature rise or the like during molding, the rapid progress of curing can be made less likely, so that the fluidity is less likely to be impaired during molding. Thereby, after the resin composition for sealing is sufficiently filled between the base material 2 and the mounted component 3, the resin composition for sealing can be cured.

[0077] The curing aid (G) preferably contains a chelate compound (G1). In this case, since the metal atom in the chelate compound (G1) can coordinate with the oxygen atom in the epoxy resin (A), the excessive thermal curing reaction of the epoxy resin (A) in the resin composition for sealing can be suppressed. Thereby, the storage stability of the resin composition for sealing can be further improved. Also, in this case, an excessive increase in the viscosity of the resin composition for sealing can also be suppressed. For this reason, the fluidity of the resin composition for sealing can be maintained in a better state.

[0078] The chelate compound (G1) contains at least one compound selected from the group consisting of, for example, aluminum acetylacetonate, titanium acetylacetonate, titanium tetraacetylacetonate, titanium acetoacetate, zirconium ethyl acetoacetate, and zirconium tetraacetylacetonate. The chelate compound (G1) preferably contains aluminum acetylacetonate.

[0079] When containing the curing aid (G), the mass ratio of the curing aid (G) to the epoxy resin (A) is preferably 0.01% by mass or more and 2.0% by mass or less, more preferably 0.03% by mass or more and 1.5% by mass or less, and still more preferably 0.1% by mass or more and 1.0% by mass or less. Within this range, the curability of the epoxy resin (A) in the encapsulating resin composition can be improved, and the gap between the base material 2 and the mounted component 3 can be sufficiently sealed with the cured product of the encapsulating resin composition.

[0080] The content of the chelate compound (G1) with respect to the curing aid (G) is preferably 20% by mass or more and 100% by mass or less, more preferably 30% by mass or more and 90% by mass or less, and still more preferably 50% by mass or more and 70% by mass or less.

[0081] [Coupling agent (H)] The encapsulating resin composition preferably contains a coupling agent (H). Examples of the coupling agent (H) include silane coupling agents. When the encapsulating resin composition contains a silane coupling agent, the compatibility of the components in the encapsulating resin composition is improved, and the dispersibility of the encapsulating resin composition is more easily enhanced. Also, even when the encapsulating resin composition contains silica (D1), the dispersibility of the encapsulating resin composition is more easily enhanced. As the silane coupling agent, an appropriate coupling agent can be employed, for example, epoxy silane coupling agents such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane may be used.

[0082] It should be noted that the additives that can be included in the encapsulating resin composition are not limited to the above. Examples of additives other than the above include, for example, appropriate curing agents, fluxes, viscosity modifiers, leveling agents, low stress agents, and pigments.

[0083] The resin composition for sealing preferably does not contain an organic solvent or has an organic solvent content of 0.5% by mass or less.

[0084] The resin composition for sealing can be obtained, for example, by blending the above components and adding appropriate additives as necessary and then mixing them. Specifically, the resin composition for sealing can be prepared, for example, by the following method.

[0085] First, a mixture is obtained by blending the components that can be included in the resin composition for sealing described above, either simultaneously or sequentially. This mixture is stirred and mixed while performing a heat treatment or a cooling treatment as necessary.

[0086] Next, additives are added to this mixture as necessary, and it is stirred again while performing a heat treatment or a cooling treatment as necessary until it is uniformly dispersed. Thereby, the resin composition for sealing can be obtained. For stirring the mixture, for example, a disper, a planetary mixer, a ball mill, a three-roll mill, and a bead mill can be appropriately combined and applied as necessary.

[0087] The resin composition for sealing can be cured, for example, by heating, whereby a cured product of the resin composition for sealing is obtained. Conditions during heating, such as heating temperature, heating time, and maximum heating temperature, etc., may be appropriately adjusted according to the type of the epoxy resin (A) and the type of the curing agent, etc.

[0088] The glass transition temperature Tg of the cured product of the resin composition for sealing is preferably 100°C or higher. If the glass transition temperature Tg is 100°C or higher, the cured product of the resin composition for sealing can have heat resistance. The glass transition temperature Tg is more preferably 110°C or higher. The glass transition temperature can be measured, for example, by TMA (Thermomechanical Analysis).

[0089] The linear expansion coefficient (CTE) of the cured product of the resin composition for sealing at temperatures below the glass transition temperature Tg is preferably 15 ppm / °C or more and 50 ppm / °C or less, more preferably 40 ppm / °C or less, and still more preferably 30 ppm / °C or less. In this case, in the resin composition for sealing and the cured product of the resin composition for sealing, warping due to heating can be less likely to occur. Therefore, cracks are less likely to occur in the cured product of the resin composition for sealing. The linear expansion coefficient of the cured product of the resin composition for sealing is obtained by calculating the slope of the tangent line based on the dimensional change at a temperature below Tg and the dimensional change at an arbitrary temperature above Tg from the results measured by TMA at Tg.

[0090] The resin composition for sealing according to this embodiment can be suitably used as an underfill material as described above. The resin composition for sealing can be particularly preferably used as a post-supply type underfill material in flip chip mounting.

[0091] <Electronic device> The electronic device 1 includes a base material 2 that supports a mounted component 3 such as a semiconductor element, a mounted component 3 that is mounted face down on the base material 2, and a sealing material 4 that seals the gap between the base material 2 and the mounted component 3. The sealing material 4 is made of a cured product of the liquid resin composition for sealing described above.

[0092] The electronic device 1 and its manufacturing method will be specifically described.

[0093] FIG. 1 shows an example of the electronic device 1 according to this embodiment. The electronic device 1 shown in FIG. 1 includes a base material 2 provided with conductor wiring 21, a mounted component 3 provided with electrodes (in FIG. 1, bump electrodes 33), and the mounted component 3 is mounted on the base material 2 by joining the bump electrodes 33 to the conductor wiring 21, and a sealing material 4 that covers the bump electrodes 33. The sealing material 4 is made of a cured product of the resin composition for sealing described above.

[0094] The base material 2 is, for example, a mother board, a package board, or an interposer board. For example, the base material 2 includes an insulating board made of glass epoxy, polyimide, polyester, ceramic, etc., and a conductive conductor wiring 21 such as copper formed on its surface. The base material 2 may be provided with a plurality of conductor wirings 21. The conductor wiring 21 includes, for example, an electrode pad.

[0095] The mounted component 3 is, for example, a semiconductor chip. The semiconductor chip is a flip-chip type chip such as, for example, BGA (Ball Grid Array), LGA (Land Grid Array), or CSP (Chip Size Package). The semiconductor chip may be a PoP (Package on Package) type chip.

[0096] The mounted component 3 includes a plurality of bump electrodes 33. The bump electrodes 33 include solder. For example, as shown in FIG. 1, the bump electrode 33 includes a pillar 31 and a solder bump 32 provided at the tip of the pillar 31. The solder bump 32 is made of solder, and thus the bump electrode 33 includes solder. The pillar 31 is made of copper, for example. It is preferable that the pitch between adjacent bump electrodes 33 among the plurality of electrodes (bump electrodes 33) in the mounted component 3 is 100 μm or less.

[0097] The melting point of the solder included in the bump electrode 33 (for example, the solder in the solder bump 32) is not particularly limited, but may be a temperature that can be melted at or below the mounting temperature (for example, 220 to 260 ° C) when mounting the mounted component 3 such as a semiconductor chip. Further, the composition of the solder is not particularly limited and may be an appropriate composition, but may be, for example, Sn-Ag based solder and Sn-Ag-Cu based solder. Note that the structure of the bump electrode 33 including solder is not limited to the above, and for example, the bump electrode 33 may include only a spherical solder bump 32 (solder ball). That is, the bump electrode 33 may not include a pillar.

[0098] In this embodiment, the mounting component 3 has a plurality of electrodes (in FIG. 1, a plurality of bump electrodes 33). The shortest pitch between the bump electrodes 33 in the mounting component 3 is 100 μm or less. Also, in the electronic device 1, the distance (gap) between the base material 2 and the mounting component 3 is 25 μm or less. That is, the electronic device 1 of this embodiment is a fine device.

[0099] In the electronic device 1 shown in FIG. 1, the encapsulant 4 fills the entire gap between the base material 2 and the mounting component 3. As a result, the encapsulant 4 covers the entire bump electrode 33 and covers the joint between the bump electrode 33 and the conductor wiring 21. That is, this encapsulant 4 is a so-called underfill.

[0100] The manufacturing method of the electronic device 1 of this embodiment includes a mounting step, an injection step, and a sealing step. In the mounting step, the mounting component 3 is surface-mounted on the base material 2 via a plurality of electrodes 33. In the injection step, a thermosetting encapsulating resin composition is injected between the base material 2 and the mounting component 3. In the sealing step, the encapsulating resin composition is cured to produce an encapsulant. The shortest pitch between the plurality of electrodes 33 is 100 μm or less, and the distance between the base material 2 and the mounting component 3 is 25 μm or less. In the sealing step, it includes curing the encapsulating resin composition by heating under pressure. Thereby, even if the interval between the electrodes of the mounting component 3 in the electronic device 1 and the interval between the base material 2 and the mounting component 3 are narrowed, voids are less likely to occur in the encapsulant 4. In particular, even when the shortest pitch between the electrodes 33 is 100 μm or less and the distance between the base material 2 and the mounting component 3 is 25 μm or less as described above, voids are less likely to occur in the encapsulant 4. 33 rooms Regarding the manufacturing method of the electronic device 1, it will be specifically described with reference to FIGS. 2A to 2E. However, the manufacturing method of the electronic device 1 is not limited to the method described below, and in the electronic device 1, it is sufficient that the gap between the base material 2 and the mounting component 3 can be covered and sealed with the above-described encapsulating resin composition.

[0101]

[0102] ​First, a substrate 2 having a conductor wiring 21 and a mounting component 3 having bump electrodes 33 are prepared (see FIG. 2A), and the substrate 2 is placed on a stage 72. Also, the bonding head 71 is made to hold the mounting component 3 such that the bump electrodes 33 of the mounting component 3 face the substrate 2 supported on the stage 72. In this state, as shown in FIG. 2B, the bonding head 71 is moved toward the stage 72. Thereby, the mounting component 3 is placed on the substrate 2. At this time, the mounting component 3 and the substrate 2 are aligned (mounting step) such that the bump electrodes 33 in the mounting component 3 and the conductor wiring 21 in the substrate 2 overlap. Then, the bump electrodes 33 and the conductor wiring 21 are electrically connected. Note that in the mounting step, it is not necessary to apply pressure, that is, when mounting the mounting component 3 on the substrate 2, it may be mounted under normal pressure.

[0103] Subsequently, the alignment between the substrate 2 and the mounting component 3 is performed as described above, and the one in which the mounting component 3 is placed on the substrate 2 is placed in a heating device. The heating device is preferably, for example, a heating furnace capable of applying pressure by air pressure. Specifically, the heating furnace may be a pressure oven (pressure oven), a pressure reflow furnace, or the like.

[0104] Next, a sealing resin composition (hereinafter, in FIGS. 2C to 2E, the material containing the sealing resin composition will be described as a "sealing material 40") is filled into the gap between the substrate 2 and the mounting component 3 (see FIG. 2C) (injection step). The sealing material 40 is preferably filled in a state of being heated to 100°C. In this case, it is easily filled by flowing well through the gap between the substrate 2 and the mounting component 3. Note that the sealing material 40 may be filled at room temperature (for example, 25°C). As the filling method, an appropriate method may be adopted, and examples thereof include a method using a dispenser, a screen printing method, an inkjet method, or a dipping method. The sealing resin composition may be injected into the gap between the substrate 2 and the mounting component 3 under reduced pressure. In the present embodiment, since the sealing resin composition has high foam-breaking properties, when injecting the sealing resin composition, even if the pressure is reduced, it is difficult for the sealing resin composition to adhere to the details of the mounting component 3 and cause contamination of the mounting component 3.

[0105] Subsequently, while increasing the pressure inside the heating furnace, the temperature is raised and heating is performed to subject the sealing material 40 and the bump electrodes 33 to a heat treatment (sealing process). For this reason, even if there are temporarily remaining bubbles in the prepared sealing material 40, when the sealing material 40 is heated and gradually cured, the pressure inside the furnace rises, so that the bubbles can be made smaller and the bubbles can be degassed from inside the sealing material 40. Further, the moisture that may be generated from the base material 2 can be dissolved in the sealing resin composition, and therefore voids derived from the moisture can be less likely to occur. For this reason, by heating while applying pressure, the voids in the sealing material 4 can be reduced. Furthermore, compared with the case where the sealing resin composition is depressurized, foaming of the sealing resin composition is less likely to occur, so that the mounting components 3 such as semiconductor elements can be less likely to be contaminated. In addition, since the sealing material 40 can be filled while having appropriate fluidity, the fillet shape of the sealing material 4 (the shape of the sealing material 40 protruding from the outer periphery of the mounting component 3) can be stabilized.

[0106] The heating and pressurization conditions inside the heating furnace are set as appropriate. For example, it is preferable to heat at a temperature increase rate of 3 to 5 °C / min to a temperature of 100 °C or higher and 200 °C or lower. Also, the pressure inside the heating furnace can be 0.1 MPa or higher and 0.8 MPa or lower. The time for performing the heat treatment can be, for example, 30 minutes or longer and 5 hours or shorter.

[0107] Thereby, the sealing material 40 is cured to produce the sealing material 4 (see Fig. 2D). After the heat treatment, the pressurization inside the heating furnace is released, and the temperature inside the heating furnace is lowered. Note that the temperature inside the heating furnace may be lowered by natural cooling or by forced cooling.

[0108] As a result, the electronic device 1 is obtained (see Fig. 2E). If necessary, after releasing the pressure, the sealing material 40 may be post-cured by further heating. In this embodiment, heating (after-cure) is included to further cure the sealing material 4 in the electronic device 1. Thereby, the connection strength between the base material 2 and the mounted component 3 in the electronic device 1 can be further enhanced. The conditions for the heat treatment in the after-cure may be appropriately set according to the composition of the resin composition for sealing and / or the electronic device manufacturing process. In the heat treatment, the maximum heating temperature is preferably, for example, 150°C or higher and 200°C or lower. In the above description, an example of the heat treatment has been described, but it is not limited thereto. For example, the maximum heating temperature may also be appropriately set according to the composition of the resin composition for sealing and the like.

[0109] As described above, by mounting the mounted component 3 on the base material 2, the electronic device 1 shown in Fig. 1 is obtained. In the manufacturing method of the electronic device 1 of this embodiment, as described above, the sealing material 4 is heat-cured by heating the resin composition for sealing (sealing material 40) while applying pressure. Therefore, even if the interval between the electrodes 33 of the mounted component 3 in the electronic device 1 and the interval between the base material 2 and the mounted component 3 are narrowed, and the space between the base material 2 and the mounted component 3 is sealed by injecting and curing the resin composition for sealing, it is possible to make it difficult for voids to occur in the sealing material 4. The electronic device 1 manufactured in this way has its connection reinforced by filling the sealing material 4 between the base material 2 and the mounted component 3, and electrical continuity between the base material 2 and the mounted component 3 is also ensured. Further, according to this embodiment, since pressurization and heating can be performed in the heating device, operations such as transferring the electronic device 1 from the heating device to another device for heat treatment after mounting for removing moisture and the like (baking) in the electronic device 1 can be omitted. Therefore, the tact (manufacturing efficiency) during manufacturing can be improved.

[0110] Note that the order of the method for manufacturing the electronic device 1 does not have to be as described above. For example, after arranging the mounting component 3 on the base material 2 and arranging the bump electrode 33 on the conductor wiring 21, the resin composition for sealing may be arranged so as to cover the bump electrode 33. Conversely, after arranging the resin composition for sealing so as to cover the bump electrode 33, the mounting component 3 may be arranged on the base material 2 and the bump electrode 33 may be arranged on the conductor wiring 21. Further, during each step of the above manufacturing, as long as the resin composition for sealing can be arranged so as to cover the bump electrode 33 as a result, the resin composition for sealing may be arranged at any time and at any position on the mounting component 3 and the base material 2.

Example

[0111] Hereinafter, specific examples of the present disclosure will be presented. However, the present disclosure is not limited only to the examples.

[0112] 1. Preparation of Resin Composition [Examples 1 to 7 and Comparative Examples 1 to 3] The components shown in Table 1 below were put into a mixer at the compounding ratios (parts by mass) shown in Table 1, stirred and mixed, and uniformly dispersed using a three-roll mill to obtain a resin composition. The details of the components shown in Table 1 are as follows. (Epoxy Resin) · Bisphenol-type epoxy resin: Bisphenol F-type epoxy resin (product name YDF8170, manufactured by Tohto Kasei Co., Ltd., epoxy equivalent 175 eq. / g). · Aromatic amino epoxy resin: product name 636, manufactured by jRR Co., Ltd. (Mixture of Phosphoric Acid and Phosphoric Acid Polyester) · Mixture of phosphoric acid and phosphoric acid polyester: product name BYK-W 9010, manufactured by BYK-Chemie Japan Co., Ltd. (composition: phosphoric acid polyester content 90% by weight or more and less than 100% by weight, phosphoric acid content 1% by weight or more and less than 10% by weight). (Additive) · Curing agent: amine curing agent (product name Kayabard A-A, manufactured by Nippon Kayaku Co., Ltd., amine equivalent 65 eq. / g). · Surface conditioner 1: Polyether-modified polydimethylsiloxane (product name BYK-306 manufactured by BYK Japan Co., Ltd.). · Surface conditioner 2: Acrylic copolymer (product name BYK-3441 manufactured by BYK Japan Co., Ltd.). · Defoamer: Product name BYK1799 manufactured by BYK Japan Co., Ltd. (a mixture of hydrophobic particles and polysiloxane). · Coupling agent: Epoxysilane (silane coupling agent. Product name KBM403 manufactured by Shin-Etsu Chemical Co., Ltd.). · Curing aid 1: Imidazole-based curing catalyst (product name 2E4MZ manufactured by Shikoku Kasei Co., Ltd. Imidazole-based compound). · Curing aid 2: Metal chelate curing aid (product name Aluminum chelate A(W) manufactured by Kawaken Fine Chemicals Co., Ltd. Aluminum trisacetylacetonate). · Colorant: Carbon black (product name MA100 manufactured by Mitsubishi Chemical Corporation). · Phosphorus derivative: Triphenylphosphine. (Inorganic filler) · Silica 1: Silica produced by the sol-gel method and surface-treated with a silane coupling agent having a phenyl group (average particle size 1.0 μm. The standard deviation in the particle size distribution is 0.04 or more and 0.5 or less.). · Silica 2: Silica produced by the sol-gel method and surface-treated with a silane coupling agent having a phenyl group (average particle size 0.3 μm. The standard deviation in the particle size distribution is 0.04 or more and 0.5 or less.). · Silica 3: Silica produced by the sol-gel method and surface-treated with a silane coupling agent having a phenyl group (average particle size 0.1 μm. The standard deviation in the particle size distribution is 0.04 or more and 0.5 or less.). · Silica 4: Silica produced by the sol-gel method and not surface-treated (average particle size 1.0 μm, the standard deviation in the particle size distribution is 0.04 or more and 0.5 or less.). · Silica 5: Silica produced by the sol-gel method and not surface-treated (average particle size 0.3 μm, the standard deviation in the particle size distribution is 0.04 or more and 0.5 or less.). · Silica 6: Silica produced by the sol-gel method and not surface-treated (average particle size 0.1 μm, standard deviation in the particle size distribution is 0.04 or more and 0.5 or less).

[0113] 2. Evaluation 2.1. Viscosity (viscosity at 25°C) The viscosity of the resin composition prepared in 1. above was measured using a BM viscometer (model TVB-10 manufactured by Toki Sangyo Co., Ltd.) under the conditions of a temperature of 25°C, a rotor No. 6, and a rotation speed of 20 rpm. Based on the obtained measurement results, evaluation was carried out according to the following criteria. A: The viscosity is less than 15 Pa·s. B: The viscosity is 15 Pa·s or more and 50 Pa·s or less. C: The viscosity is 50 Pa· s or more.

[0114] 2.2. Viscosity at high temperature (viscosity at 100°C) The viscosity of the resin composition prepared in 1. above was measured using a rheometer (model MCR-10 manufactured by Anton Paar) under the conditions of a temperature of 100°C and a rotation speed of 1 rpm. Based on the obtained measurement results, evaluation was carried out according to the following criteria. A: The viscosity is less than 0.10 Pa·s. B: The viscosity is 0.10 Pa·s or more and 0.15 Pa·s or less. C: The viscosity is 0.15 Pa· s or more.

[0115] Further, when the resin composition prepared in 1. above was heated from 25°C at a heating rate of 30°C / min, the viscosity at the time when the curing temperature was reached was 0.15 Pa·s or less in all of Examples 1 to 7, whereas it exceeded 0.15 Pa·s in Comparative Examples 1 to 3. The curing temperature was obtained by applying the sealing resin composition to the stage of a rheometer with a rheometer, heating the stage to 80°C to 150°C, and then measuring the viscosity of the sealing resin composition after heating at 100°C for 2 hours under the condition of a rotation speed of 1 rpm. Also, the viscosity of the sealing resin composition at the time when the curing temperature was reached was obtained by allowing the sealing resin composition to stand on a stage preheated to a temperature within the range of 80°C to 150°C using a rheometer, heating at 150°C for 2 hours, and then measuring under the condition of a rotation speed of 1 rpm.

[0116] 2.3. Foam-breaking property 10 g of the sealing resin composition was weighed into an appropriate container having a height of 55 mm or more, sealed, and degassed by reducing the pressure to 200 Pa / 10 min at a temperature of 25°C. After 10 minutes, the height of the deposit from the container wall was measured, where the sealing resin composition had spouted from the liquid surface due to the reduced pressure and adhered to the wall of the container. The obtained measurement results (mm) are shown in Table 1.

[0117] In all of Examples 1 to 7, it was 45 mm or less, and in Examples 1 to 6, it was 40 mm or less. In particular, in Examples 3 to 6, it was 30 mm or less, and the degree of foaming was very low. In contrast, in Comparative Examples 1 to 3, foaming occurred in such a way that it exceeded the upper limit of 55 mm of the height of the container and adhered to the upper surface of the container. As a result, it was suggested that Examples 1 to 7 had high foam-breaking properties, had few voids in the resin composition, and were less likely to generate voids in the sealing material when cured, whereas Comparative Examples 1 to 3 had low foam-breaking properties, had voids remaining in the resin composition, and were likely to have voids remaining in the sealing material when cured.

[0118] In addition, in each of the examples and comparative examples, the foam-breaking property at room temperature (25°C) was confirmed. However, even at temperatures of 100°C or higher, in Examples 1 to 7, the viscosity of the sealing resin composition is lower and the surface tension is higher than in the case of 25°C. Therefore, it is presumed that, as in the case of 25°C, they have excellent foam-breaking properties.

[0119] 2.4. Fluidity Two flat glass plates were placed on a heatable pedestal (stage) with a gap of 25 μm between them, and the two glass plates were heated by setting the temperature of the stage to 100°C. After the temperature of the glass plates reached 100°C, the resin composition prepared in 1. above was injected into the 25-μm gap, and the gap was made to flow using capillary action. The time until the resin composition advanced a distance of 30 mm from the start of injection was measured. Based on the results obtained by the measurement, evaluation was carried out according to the following criteria. A: The time until it advances 30 mm is less than 400 seconds. B: The time until it advances 30 mm is 400 seconds or more and less than 500 seconds. C: The time until it advances 30 mm is 500 seconds or more.

[0120] 2.5. Void An electronic device was fabricated as follows using the resin composition prepared in 1. above.

[0121] As a semiconductor chip (FC-BGA: Flip Chip Ball Grid Array), Walts TEG FC200JY (10 mm × 10 mm × 300 μm) manufactured by WALTS was prepared.

[0122] As a substrate, R-G535E manufactured by Panasonic Corporation was processed (52.5 mm × 52.5 mm × 1.2 μm) so that the above chip could be mounted.

[0123] The substrate was placed on the stage of a pressure oven, and the semiconductor chip was overlaid with a flip chip and aligned.

[0124] Subsequently, while heating the resin composition prepared in 1. above to 100°C, the gap between the base material and the semiconductor chip was filled. Then, in a heating device having a heating furnace, while repeating pressurization and depressurization at a maximum pressurization pressure of 0.7 MPa, the resin composition was heated at 100°C for 2 hours with the resin composition intervening in the gap between the base material and the semiconductor chip to cure the resin composition.

[0125] After continuing or releasing the pressurization, the resin composition between the base material and the semiconductor chip was completely cured by heating at 150°C for 2 hours. Thereby, a test electronic device was obtained. The voids in the encapsulant of this electronic device were investigated using an ultrasonic flaw detector (SAT). As a result, when no voids were observed, it was evaluated as "A", when 10 or fewer minute voids of 200 μm or less were observed, it was evaluated as "B", and when more voids than that were observed, it was evaluated as "C".

[0126] [Table 1] [Explanation of Reference Signs]

[0127] 1 Electronic device 2 Base material 3 Mounted component 4 Encapsulant

Claims

1. A mounting step of surface-mounting a mounted component on a base material via a plurality of electrodes, An injection step of injecting a thermosetting resin composition for sealing, which is liquid at room temperature, between the base material and the mounted component, A sealing step of curing the resin composition for sealing to produce a sealing material, and including, The shortest pitch between the plurality of electrodes is 100 μm or less, and the distance between the base material and the mounted component is 25 μm or less, In the sealing step, a method for manufacturing an electronic device, wherein the resin composition for sealing is cured by heating while repeatedly pressurizing and depressurizing the atmospheric pressure in a heating furnace in the heating furnace.

2. The resin composition for sealing has a viscosity at 100 °C of 0.15 Pa·s or less, The method for manufacturing an electronic device according to Claim 1.

3. The resin composition for sealing has a property that when heated under any one of the heating conditions with a temperature rising rate of 0.5 °C / min to 50 °C / min from 25 °C, the viscosity at the time when the curing temperature is reached is 0.15 Pa·s or less, The method for manufacturing an electronic device according to Claim 1 or 2.

4. The resin composition for sealing contains an epoxy resin (A), phosphoric acid (B), and a phosphoric acid polyester (C), The method for manufacturing an electronic device according to any one of Claims 1 to 3.

5. The resin composition for sealing contains at least one of an antifoaming agent (E) and a surface conditioner (F), The method for manufacturing an electronic device according to any one of Claims 1 to 4.

6. Bottom area: 450 mm 2 When the resin composition for sealing is placed in a container with a bottom area of 450 mm and a height of 55 mm such that the liquid level height is 20 mm from the bottom surface of the container, and the inside of the container is depressurized at 25°C at 200 Pa / 10 min, the height at which the resin composition for sealing sprays out and adheres to the wall surface of the container is 40 mm or less from the bottom surface of the container. The method for manufacturing an electronic device according to any one of Claims 1 to 5.

7. An electronic device manufactured by the method for manufacturing an electronic device according to any one of Claims 1 to 6, Electronic device.

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