Sealing resin sheet

Abstract

A resin sheet 1 for sealing according to the present invention contains a thermosetting resin and seals an element. The complex viscosity η* of this resin sheet for sealing is evaluated by means of dynamic viscoelasticity measurement (1) for temperature dispersion. The ratio of the minimum complex viscosity η* MIN at 80 to 120°C from 80°C to 120°C to the complex viscosity η* at 50°C at 50°C, namely (η* MIN at 80 to 120°C / η* at 50°C) is 0.170 or more.

Description

[Technical field]

[0001] The present invention relates to an encapsulating resin sheet. [Background technology]

[0002] Conventionally, it is known that a sealing sheet containing a thermosetting resin is used to seal a semiconductor element or an electronic component mounted on a substrate by pressing to form a sealed body, and then the thermosetting resin in the sealed body is thermally cured to form a cured body from the sealed body (for example, see Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-162909 A Summary of the Invention [Problem to be solved by the invention]

[0004] As electronic devices become more sophisticated, the semiconductor elements and electronic components used in them are also required to be smaller. Accordingly, there is a demand for improved dimensional accuracy during curing for the resin (cured body) that protects the semiconductor elements and electronic components. Specifically, there is a demand to further reduce the amount of cured body that penetrates between the semiconductor elements and electronic components and the substrate from the side edges of the semiconductor elements and electronic components. There is also a demand for excellent sealing properties for the elements.

[0005] The present invention provides an encapsulating resin sheet that can reduce the intrusion of a cured body between an element such as a semiconductor element or an electronic component and a substrate, or an encapsulating resin sheet that has excellent sealing properties for elements. [Means for solving the problem]

[0006] The present invention (1) is an encapsulating resin sheet for encapsulating an element, which contains a thermosetting resin, and is characterized in that the complex viscosity η * Evaluate Temperature: 50℃~150℃ Frequency: 1Hz Heating rate: 10℃ / min Mode: Shear Complex viscosity η at 50℃ * at 50℃ Minimum complex viscosity η at 80℃~120℃ * MIN at 80 to 120℃ The ratio (η * MIN at 80 to 120℃ / η * at 50℃ ) is 0.170 or more.

[0007] The present invention (2) is a method for measuring the complex viscosity H of the sealing resin sheet by dynamic viscoelasticity measurement [2] of frequency dispersion based on the following conditions: * Evaluate Temperature: 90℃ Frequency: 0.01Hz~10Hz Mode: Shear Complex viscosity H at a frequency of 0.01 Hz * at 0.01Hz Complex viscosity H at a frequency of 10 Hz * at 10Hz The ratio (H * at 10Hz / H * at 0.01Hz ) is 0.0020 or less.

[0008] The present invention (3) is characterized in that, in the temperature dispersion dynamic viscoelasticity measurement [1], the second minimum complex viscosity η in the temperature range of 50 ° C. to 150 ° C. * MIN at 50 to 150℃ The sealing resin sheet according to (1) or (2), wherein the temperature T corresponding to is in the range of 80°C to 120°C.

[0009] The present invention (4) includes the encapsulating resin sheet according to (3), in which a ratio (G'' / G') of a loss shear modulus G'' to a storage shear modulus G' at the temperature T is 0.4 or less. Effect of the Invention

[0010] In the encapsulating resin sheet of the present invention, the complex viscosity η * at 50℃ Minimum complex viscosity η at 80℃~120℃ * MIN at 80 to 120℃ The ratio (η * MIN at 80 to 120℃ / η * at 50℃ ) is as high as 0.170 or more. Therefore, when the encapsulating resin sheet is placed on an element, an encapsulant is formed by pressing, and then the encapsulant is heated to form a hardened body, it is possible to reduce the intrusion of the hardened body between the element and the substrate.

[0011] In addition, in the encapsulating resin sheet of the present invention, the complex viscosity H * at 0.01Hz Complex viscosity H at a frequency of 10 Hz * at 10Hz The ratio (H * at 10Hz / H * at 0.01Hz ) is low at 0.0020 or less. In other words, the frequency dependency of the encapsulating resin sheet during shearing (pressing) is high. Therefore, when the encapsulating resin sheet is placed on an element and pressed, the complex viscosity of the encapsulating resin sheet is sufficiently reduced based on the shearing force of the press. Therefore, the peripheral edge of the gap between the element and the substrate can be reliably sealed. As a result, the sealing property for the element is excellent. [Brief description of the drawings]

[0012] [Figure 1]1A to 1D are cross-sectional views showing a process of manufacturing an electronic element package by encapsulating a plurality of electronic elements using one embodiment of the encapsulating resin sheet of the present invention, where FIG. 1A shows a process of preparing an encapsulating resin sheet, FIG. 1B shows a process of preparing a plurality of electronic elements, FIG. 1C shows a process of pressing the encapsulating resin sheet to form an encapsulated body, and FIG. 1D shows a process of heating the encapsulated body to form a hardened body. [Diagram 2] 2A to 2D are cross-sectional views showing a process of manufacturing an electronic element package by encapsulating a plurality of electronic elements using an encapsulating multilayer resin sheet having the encapsulating resin sheet shown in FIG. 1A, in which FIG. 2A shows a process of preparing the encapsulating multilayer resin sheet, FIG. 2B shows a process of preparing a plurality of electronic elements, FIG. 2C shows a process of pressing the encapsulating multilayer resin sheet to form an encapsulated body, and FIG. 2D shows a process of heating the encapsulated body to form a hardened body. [Diagram 3] 3A to 3D show a method for measuring the encapsulating body penetration length X and the hardened body penetration length Y from the encapsulating multilayer resin sheet shown in FIG. 2A, in which FIG. 3A shows step A of forming a sample sheet from the encapsulating multilayer resin sheet, FIG. 3B shows step B of preparing a dummy element, FIG. 3C shows step C of pressing the encapsulating multilayer resin sheet to form an encapsulated body, and FIG. 3D shows step D of heating the encapsulated body to form a hardened body. [Figure 4] FIG. 4 shows the complex viscosity η*-temperature curves plotted in the dynamic viscoelasticity measurement [1] of the temperature dispersion in Example 1 and Comparative Example 2. [Diagram 5] FIG. 5 is a complex viscosity H*-frequency curve plotted in the dynamic viscoelasticity measurement of frequency dispersion [2] in Example 1 and Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <Sealing resin sheet> An embodiment of the encapsulating resin sheet of the present invention will be described.

[0014] The encapsulating resin sheet is a resin sheet for encapsulating an element, and has a generally plate shape (film shape) extending in a plane direction perpendicular to the thickness direction. The encapsulating resin sheet contains a thermosetting resin (described later).

[0015] <Temperature Dependence of Sealing Resin Sheet> The complex viscosity η of the encapsulating resin sheet was measured by dynamic viscoelasticity measurement [1] under the following conditions: * Evaluate the complex viscosity η * The ratio is as follows: Temperature: 50℃~150℃ Frequency: 1Hz Heating rate: 10℃ / min Mode: Shear

[0016] Complex viscosity η at 50℃ * at 50℃ Minimum complex viscosity η at 80℃~120℃ * MIN at 80 to 120℃ The ratio (η * MIN at 80 to 120℃ / η * at 50℃ The lower limit of the minimum complex viscosity η is 0.170, preferably 0.200, more preferably 0.250, even more preferably 0.300, particularly preferably 0.350, and most preferably 0.400. * MIN at 80 to 120℃ The ratio (η * MIN at 80 to 120℃ / η * at 50℃ ) can have an upper limit of, for example, 1.000 or 0.950.

[0017] The above-mentioned "Complex viscosity at 50°C η * at 50℃ The temperature of 50° C. in "" corresponds to the temperature (sealing temperature) when the sealing resin sheet is pressed to seal the element, or a temperature in the vicinity thereof.

[0018] In addition, the above-mentioned "minimum complex viscosity η at 80 ° C to 120 ° C" * MINat 80 to 120℃ The temperature of 80° C. to 120° C. in "heating" corresponds to the temperature (curing temperature) when the sealed body formed by pressing is heated or a temperature close to the temperature.

[0019] Complex viscosity η at 50℃ * at 50℃ The lower limit of the complex viscosity η at 50° C. is, for example, 1,000 Pa·s, or preferably 5,000 Pa·s. * at 50℃ The upper limit is, for example, 3,000,000 Pa·s, or preferably 1,000,000 Pa·s.

[0020] Minimum complex viscosity η at 80℃~120℃ * MIN at 80 to 120℃ The lower limit of the minimum complex viscosity η at 80°C to 120°C is, for example, 500 Pa·s, or preferably 1,000 Pa·s. * MIN at 80 to 120℃ The upper limit is, for example, 800,000 Pa·s, preferably 500,000 Pa·s.

[0021] In the dynamic viscoelasticity measurement of temperature dispersion [1], the same sealing resin sheet is laminated in the thickness direction and processed into a disk shape to prepare a sample sheet. The complex viscosity η * Measure.

[0022] The dynamic viscoelasticity measurement of temperature dispersion [1] is a measurement to evaluate the temperature dependency of the encapsulating resin sheet, specifically, a measurement to evaluate the degree of decrease in the complex viscosity of the encapsulating resin sheet when heated.

[0023] In the dynamic viscoelastic measurement of temperature dispersion [1], the complex viscosity η * This curve shows the complex viscosity η * decreases and reaches a minimum (minimum complex viscosity η * MIN), the complex viscosity increases with further heating. The degree of the complex viscosity decrease (the length of the arrow in FIG. 4) is evaluated by the decrease in complex viscosity at the minimum mentioned above.

[0024] In one embodiment, it is preferable that the degree of decrease in the complex viscosity of the encapsulating resin sheet during heating is small, and the complex viscosity η * It is preferable that the absolute value of is large.

[0025] Specifically, the solid line labeled "Example 1" shows a smaller degree of decrease in complex viscosity at the minimum than the dashed line labeled "Comparative Example 2", and therefore the amount of penetration of the hardened body during heating can be suppressed. On the other hand, in Comparative Example 2, the degree of decrease in complex viscosity at the minimum is large, and therefore the amount of penetration of the hardened body during heating increases.

[0026] Then, the minimum complex viscosity η * MIN at 80 to 120℃ The ratio (η * MIN at 80 to 120℃ / η * at 50℃ ) does not satisfy the above-mentioned lower limit, when the encapsulating resin sheet is placed on an element, pressed to form an encapsulated body, and heated to form a cured body, it is not possible to sufficiently reduce intrusion of the cured body between the element and the substrate.

[0027] In addition, the dynamic viscoelasticity measurement of this temperature dispersion [1] showed that the second minimum complex viscosity η * MIN at 50 to 150℃ The lower limit of the temperature T corresponding to is, for example, 80° C., preferably 85° C., more preferably 90° C., even more preferably 95° C., and particularly preferably 100° C. In addition, the second minimum complex viscosity η * MIN at 50 to 150℃ The upper limit of the temperature T corresponding to is, for example, 120°C, preferably 115°C, more preferably 110°C, and even more preferably 105°C.

[0028] Second lowest complex viscosity η * MIN at 50 to 150℃If the temperature T corresponding to is equal to or higher than the above-mentioned lower limit, the sheet shape can be maintained at room temperature, and the encapsulating resin sheet can be made to flow sufficiently when heated. * MIN at 50 to 150℃ If the temperature T corresponding to is equal to or lower than the above upper limit, the curing speed of the sealing resin sheet does not slow down, and the time (takt time) of the manufacturing process can be shortened.

[0029] In particular, the second lowest complex viscosity η * MIN at 50 to 150℃ If the temperature T corresponding to is in the range of 80°C to 120°C, this temperature T is the minimum complex viscosity η * MIN at 80 to 120℃ That is, the second lowest complex viscosity η * MIN at 50 to 150℃ and the minimum complex viscosity η at 80°C to 120°C. * MIN at 80 to 120℃ are the same.

[0030] This allows the encapsulating resin sheet to flow sufficiently during actual use, and also prevents the hardening speed of the encapsulating resin sheet from slowing down, allowing the time (takt time) of the manufacturing process to be shortened.

[0031] On the other hand, the second lowest complex viscosity η * MIN at 50 to 150℃ If the temperature T corresponding to is less than 80° C., as shown by the dashed-dotted line in FIG. 4, the curing speed of the encapsulating resin sheet during actual use may be too fast, making it impossible to sufficiently flow the encapsulating resin sheet.

[0032] On the other hand, the second lowest complex viscosity η * MIN at 50 to 150℃ If the temperature T corresponding to exceeds 120° C. as shown by the two-dot dashed line in FIG. 4, the curing speed of the sealing resin sheet becomes slow, and the time (takt time) of the manufacturing process may not be shortened.

[0033] Furthermore, the upper limit of the ratio (G'' / G') of the loss shear modulus G'' at the above-mentioned temperature T to the storage shear modulus G' at the same temperature T is, for example, 0.6, preferably 0.5, more preferably 0.45, even more preferably 0.4, and particularly preferably 0.35. The lower limit of the ratio (G'' / G') is, for example, 0.01, preferably 0.1, and more preferably 0.15.

[0034] If the ratio (G'' / G') of the loss shear modulus G'' (viscous term) to the storage shear modulus G' (elastic term) is below the above-mentioned upper limit, the viscous term to the elastic term will be below a specified ratio, and the amount of penetration of the hardened body can be suppressed as much as possible at the hardening temperature T or a temperature close to it.

[0035] <Frequency Dependence of Sealing Resin Sheet> In addition, the complex viscosity H of the encapsulating resin sheet was measured by dynamic viscoelasticity measurement [2] using frequency dispersion under the following conditions. * Evaluate the complex viscosity H * The ratio is as follows: Temperature: 90℃ Frequency: 0.01Hz~10Hz Mode: Shear

[0036] Complex viscosity H at a frequency of 0.01 Hz * at 0.01Hz Complex viscosity H at a frequency of 10 Hz * at 10Hz The ratio (H * at 10Hz / H * at 0.01Hz The upper limit of the complex viscosity H at a frequency of 10 Hz is, for example, 0.0020, preferably 0.0019, more preferably 0.0017, and even more preferably 0.0015. * at 10Hz The ratio (H * at 10Hz / H * at 0.01Hz ) is, for example, 0.0001, preferably 0.0005, and more preferably 0.0012.

[0037] Complex viscosity H at a frequency of 0.01 Hz * at 0.01Hz The lower limit of the complex viscosity H at a frequency of 0.01 Hz is, for example, 100,000 Pa·s, preferably 200,000 Pa·s. * at 0.01Hz The upper limit is, for example, 50,000,000 Pa·s, preferably 20,000,000 Pa·s.

[0038] Complex viscosity H at a frequency of 10 Hz * at 10Hz The lower limit of the complex viscosity H at a frequency of 10 Hz is, for example, 500 Pa·s, preferably 1,000 Pa·s. * at 10Hz The upper limit is, for example, 500,000 Pa·s, or preferably 100,000 Pa·s.

[0039] In the dynamic viscoelasticity measurement of frequency dispersion [2], multiple identical sealing resin sheets are laminated in the thickness direction and processed into a disk shape to prepare a sample sheet. The complex viscosity H of this sample sheet is measured using a rheometer (viscoelasticity measuring device). * Measure.

[0040] The dynamic viscoelasticity measurement of frequency dispersion [2] is a measurement to evaluate the frequency dependence of the encapsulating resin sheet; specifically, it is a measurement to evaluate the degree of decrease in the complex viscosity of the encapsulating resin sheet when the shear stress applied to the encapsulating resin sheet at 90°C increases.

[0041] Note that 90° C. is a set temperature for evaluating the frequency dependency of the sealing resin sheet, and specifically, it is assumed to be a pressing temperature when forming a sealer from the sealing resin sheet.

[0042] Specifically, the dynamic viscoelasticity measurement of frequency dispersion [2] is a measurement to evaluate the frequency dependence of a sealing resin sheet, specifically, a measurement to evaluate the degree of decrease in complex viscosity of the sealing resin sheet during shear (press) (sealing).

[0043] In frequency-dispersive dynamic viscoelastic measurements [2], the complex viscosity H * -frequency curves are obtained. These curves show that as the frequency increases, the complex viscosity H * decreases.

[0044] And the complex viscosity at a frequency of 0.01 Hz is * at 0.01Hz is the complex viscosity when no shear stress has been applied to the sealing resin sheet. On the other hand, the complex viscosity H * at 10Hz is the complex viscosity when a shear stress (for example, high shear stress) (specifically, pressing) is applied to the sealing resin sheet.

[0045] It is preferable that the degree of decrease in the complex viscosity of the sealing resin sheet when a shear stress is applied (the length of the arrow in FIG. 5) is large. That is, in this embodiment, the ratio (H * at 10Hz / H * at 0.01Hz ) is preferably small.

[0046] Ratio(Η * at 10Hz / H * at 0.01Hz ) is equal to or less than the upper limit, the complex viscosity is sufficiently reduced based on the shear applied to the encapsulating resin sheet when the encapsulating resin sheet is placed on the element and pressed. Therefore, the peripheral edge of the gap between the element and the substrate can be reliably sealed. In addition, in a state where no shear stress is applied during heat curing, the flow of the encapsulating resin sheet can be reduced.

[0047] Furthermore, as shown in FIG. 1C, when multiple elements are arranged at intervals from each other in the planar direction, when the sealing resin sheet is pressed, the complex viscosity is sufficiently reduced due to the shear applied to the sealing resin sheet, so that the sealing resin sheet can penetrate between the multiple elements and reliably cover the peripheral side surfaces of the multiple elements.

[0048] <Materials (composition) of sealing resin sheets> As described above, the encapsulating resin sheet contains a thermosetting resin. Specifically, the material of the encapsulating resin sheet is a thermosetting resin composition containing a thermosetting resin.

[0049] Examples of the thermosetting resin include epoxy resin, silicone resin, urethane resin, polyimide resin, urea resin, melamine resin, unsaturated polyester resin, etc. These may be used alone or in combination of two or more kinds.

[0050] The thermosetting resin is preferably an epoxy resin. The epoxy resin is prepared as an epoxy resin composition containing a base resin, a curing agent, and a curing accelerator.

[0051] Examples of the base agent include bifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, modified bisphenol A type epoxy resin, modified bisphenol F type epoxy resin, and biphenyl type epoxy resin, and polyfunctional epoxy resins having three or more functional groups such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, trishydroxyphenylmethane type epoxy resin, tetraphenylolethane type epoxy resin, and dicyclopentadiene type epoxy resin. These base agents can be used alone or in combination of two or more. As the base agent, preferably, bifunctional epoxy resins, more preferably, bisphenol F type epoxy resins, can be used.

[0052] The lower limit of the epoxy equivalent of the base resin is, for example, 10 g / eq., or preferably 100 g / eq. The upper limit of the epoxy equivalent of the base resin is, for example, 300 g / eq., or preferably 250 g / eq.

[0053] The lower limit of the softening point of the base agent is, for example, 50° C., preferably 70° C., more preferably 72° C., and even more preferably 75° C. The upper limit of the softening point of the base agent is, for example, 130° C., preferably 110° C., and more preferably 90° C.

[0054] If the softening point of the base resin is equal to or higher than the above-mentioned lower limit, the encapsulating resin sheet 1 can flow in the step shown in Fig. 1C. Therefore, the time required for the step shown in Fig. 1C can be shortened, and one surface in the thickness direction of the encapsulating resin sheet 1 can be flattened in the step shown in Fig. 2C.

[0055] The lower limit of the ratio of the main agent in the thermosetting resin composition is, for example, 1 mass%, preferably 3 mass%, more preferably 10 mass%. The upper limit of the ratio of the main agent in the thermosetting resin composition is, for example, 30 mass%, preferably 15 mass%, more preferably 12.5 mass%. The lower limit of the ratio of the main agent in the epoxy resin composition is, for example, 30 mass%, preferably 50 mass%. The upper limit of the ratio of the main agent in the epoxy resin composition is, for example, 80 mass%, preferably 70 mass%.

[0056] The curing agent is a latent curing agent that cures the above-mentioned base material by heating. For example, the curing agent may be a phenolic resin such as phenol novolac resin. If the curing agent is a phenolic resin, the phenolic resin and the base material together form a cured product having high heat resistance and high chemical resistance. Therefore, the cured product has excellent sealing reliability.

[0057] The ratio of the curing agent is set to the following equivalent ratio. Specifically, the lower limit of the total of the hydroxyl groups in the phenolic resin relative to 1 equivalent of the epoxy group in the base agent is, for example, 0.7 equivalents, preferably 0.9 equivalents. The upper limit of the total of the hydroxyl groups in the phenolic resin relative to 1 equivalent of the epoxy group in the base agent is, for example, 1.5 equivalents, preferably 1.2 equivalents. Specifically, the lower limit of the number of parts of the curing agent contained relative to 100 parts by mass of the base agent is, for example, 20 parts by mass, preferably 40 parts by mass. The upper limit of the number of parts of the curing agent contained relative to 100 parts by mass of the base agent is, for example, 80 parts by mass, preferably 60 parts by mass.

[0058] The curing accelerator is a catalyst (heat-curing catalyst) that promotes the curing of the main agent by heating. Examples of the curing accelerator include organic phosphorus compounds, such as imidazole compounds like 2-phenyl-4,5-dihydroxymethylimidazole (2PHZ-PW). Preferably, imidazole compounds are included. The lower limit of the content of the curing accelerator with respect to 100 parts by mass of the main agent is, for example, 0.05 parts by mass. The upper limit of the content of the curing accelerator with respect to 100 parts by mass of the main agent is, for example, 5 parts by mass.

[0059] The lower limit of the content ratio of the epoxy resin composition in the thermosetting resin composition (sealing resin sheet) is, for example, 5% by mass, preferably 15% by mass, more preferably 17% by mass. The upper limit of the content ratio of the epoxy resin composition in the thermosetting resin composition (sealing resin sheet) is, for example, 30% by mass, preferably 25% by mass, more preferably 20% by mass, and even more preferably 18% by mass.

[0060] Also, the material of the sealing resin sheet preferably further contains a layered silicate compound. The material of the sealing resin sheet is preferably a thermosetting resin composition containing a thermosetting resin and a layered silicate compound.

[0061] The layered silicate compound is dispersed in the thermosetting resin in the thermosetting resin composition (sealing resin sheet). Also, the layered silicate compound is a flow regulator when forming a sealing body and a cured body (described later) from the sealing resin sheet. Specifically, it is a flow reduction agent during curing that reduces the fluidity of the cured body when heating the sealing resin sheet to form a cured body.

[0062] The layered silicate compound is, for example, a silicate having a structure (three-dimensional structure) in which layers spread two-dimensionally (in the plane direction) are stacked in the thickness direction, and is called a phyllosilicate.

[0063] Specifically, examples of the layered silicate compound include smectites such as montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, and stevensite, kaolinite, halloysite, talc, and mica. As the layered silicate compound, preferably, smectite is used from the viewpoint of improving the mixability with the thermosetting resin, and more preferably, montmorillonite is used.

[0064] The layered silicate compound may be an unmodified one whose surface is not modified, or may be a modified one whose surface is modified with an organic component.Preferably, the layered silicate compound is surface-modified with an organic component from the viewpoint of obtaining excellent affinity with thermosetting resin.Specifically, the layered silicate compound may be an organically modified smectite whose surface is modified with an organic component, or more preferably, an organically modified bentonite whose surface is modified with an organic component.

[0065] Examples of the organic component include organic cations (onium ions) such as ammonium, imidazolium, pyridinium, and phosphonium.

[0066] Examples of ammonium include dimethyl distearyl ammonium, distearyl ammonium, octadecyl ammonium, hexyl ammonium, octyl ammonium, 2-hexyl ammonium, dodecyl ammonium, trioctyl ammonium, etc. Examples of imidazolium include methyl stearyl imidazolium, distearyl imidazolium, methyl hexyl imidazolium, dihexyl imidazolium, methyl octylimidazolium, dioctylimidazolium, methyl dodecyl imidazolium, didodecyl imidazolium, etc. Examples of pyridinium include stearyl pyridinium, hexyl pyridinium, octyl pyridinium, dodecyl pyridinium, etc. Examples of the phosphonium include dimethyl distearyl phosphonium, distearyl phosphonium, octadecyl phosphonium, hexyl phosphonium, octyl phosphonium, 2-hexyl phosphonium, dodecyl phosphonium, and trioctyl phosphonium. The organic cation can be used alone or in combination of two or more kinds. Preferably, ammonium is used, and more preferably, dimethyl distearyl ammonium is used.

[0067] As the organically modified layered silicate compound, preferably, organically modified smectite the surface of which is modified with ammonium, and more preferably, organically modified bentonite the surface of which is modified with dimethyldistearylammonium, is used.

[0068] The lower limit of the average particle size of the layered silicate compound is, for example, 1 nm, preferably 5 nm, more preferably 10 nm. The upper limit of the average particle size of the layered silicate compound is, for example, 100 μm, preferably 50 μm, more preferably 10 μm. The average particle size of the layered silicate compound is determined as a D50 value (cumulative 50% median size) based on the particle size distribution determined by a particle size distribution measurement method in a laser scattering method.

[0069] As the layered silicate compound, commercially available products can be used. For example, the Esben series (manufactured by Hojun Co., Ltd.) is a commercially available organic bentonite product.

[0070] The lower limit of the content of the layered silicate compound in the thermosetting resin composition (sealing resin sheet) is, for example, 2 mass%, preferably 3 mass%, more preferably 3.5 mass%, even more preferably 4 mass%, and particularly preferably 4.5 mass%. The upper limit of the content of the layered silicate compound in the thermosetting resin composition (sealing resin sheet) is, for example, 25 mass%, preferably 10 mass%, more preferably 9 mass%, even more preferably 7 mass%, and particularly preferably 6 mass%.

[0071] When the content of the layered silicate compound is equal to or higher than the above-mentioned lower limit, the complex viscosity η * at 50℃ The minimum complex viscosity η * MIN at 80 to 120℃ The ratio (η * MIN at 80 to 120℃ / η * at 50℃ ) can be set to be equal to or greater than the lower limit mentioned above.

[0072] When the content of the layered silicate compound is equal to or less than the above upper limit, the space (void) formed outside the side edge of the element can be made small, or the formation of the void can be suppressed.

[0073] The thermosetting resin composition may further contain an inorganic filler other than the layered silicate compound.

[0074] Examples of inorganic fillers include silicate compounds other than layered silicate compounds such as orthosilicate, sorosilicate, and inosilicate, and silicon compounds (other than layered silicate compounds) such as quartz (silicic acid), silica (anhydrous silicic acid), and silicon nitride. Examples of inorganic fillers include alumina, aluminum nitride, and boron nitride. These can be used alone or in combination of two or more. Preferably, silicon compounds other than layered silicate compounds are used, and more preferably, silica.

[0075] The shape of the inorganic filler is not particularly limited, and examples thereof include a substantially spherical shape, a substantially plate shape, a substantially needle shape, an irregular shape, etc. A substantially spherical shape is preferable.

[0076] The upper limit of the average value of the maximum length of the inorganic filler (similar to the average particle diameter if the filler is substantially spherical) is, for example, 50 μm, preferably 20 μm, more preferably 10 μm. The lower limit of the average value of the maximum length of the inorganic filler is, for example, 0.1 μm, preferably 0.5 μm. The average particle diameter of the inorganic filler is determined as the D50 value (cumulative 50% median diameter) based on the particle size distribution determined by, for example, a particle size distribution measurement method in a laser scattering method.

[0077] Additionally, the inorganic filler may include a first filler and a second filler having an average maximum length that is smaller than the average maximum length of the first filler.

[0078] The lower limit of the average maximum length of the first filler is, for example, 1 μm, or preferably 3 μm.The upper limit of the average maximum length of the first filler is, for example, 50 μm, or preferably 30 μm.

[0079] The upper limit of the average value of the maximum length of the second filler is, for example, 0.9 μm, preferably 0.8 μm.The lower limit of the average value of the maximum length of the second filler is, for example, 0.01 μm, preferably 0.1 μm.

[0080] The lower limit of the ratio of the average maximum length of the first filler to the average maximum length of the second filler is, for example, 2, preferably 5. The upper limit of the ratio of the average maximum length of the first filler to the average maximum length of the second filler is, for example, 50, preferably 20.

[0081] The materials of the first and second fillers may be the same or different.

[0082] Furthermore, the surface of the inorganic filler may be partially or entirely treated with a silane coupling agent or the like.

[0083] The lower limit of the content of the inorganic filler in the thermosetting resin composition (sealing resin sheet) is, for example, 50 mass%, preferably 55 mass%, more preferably 60 mass%, and even more preferably 65 mass%. The upper limit of the content of the inorganic filler in the thermosetting resin composition (sealing resin sheet) is, for example, 90 mass%, preferably 85 mass%, more preferably 80 mass%, and even more preferably 75 mass%.

[0084] The lower limit of the number of parts of the layered silicate compound contained relative to 100 parts by mass of the inorganic filler is, for example, 1 part by mass, preferably 2 parts by mass, more preferably 3 parts by mass, and even more preferably 5 parts by mass. The upper limit of the number of parts of the layered silicate compound contained relative to 100 parts by mass of the inorganic filler is, for example, 25 parts by mass, preferably 20 parts by mass, more preferably 15 parts by mass, and even more preferably 10 parts by mass.

[0085] When the content ratio and / or the content number of the inorganic filler is equal to or more than the above-mentioned lower limit, the sealing resin sheet 1 can flow in the step shown in FIG. 1C.

[0086] When the inorganic filler includes a first filler and a second filler, the lower limit of the content ratio of the first filler in the thermosetting resin composition (sealing resin sheet) is, for example, 30 mass%, preferably 40 mass%, in the thermosetting resin composition. The upper limit of the content ratio of the first filler in the thermosetting resin composition (sealing resin sheet) is, for example, 60 mass%, preferably 50 mass%, in the thermosetting resin composition. The lower limit of the number of parts of the second filler relative to 100 parts by mass of the first filler is, for example, 30 parts by mass, preferably 40 parts by mass, more preferably 50 parts by mass. The upper limit of the number of parts of the second filler relative to 100 parts by mass of the first filler is, for example, 70 parts by mass, preferably 60 parts by mass, more preferably 55 parts by mass.

[0087] The thermosetting resin composition may contain, for example, a thermoplastic resin, a pigment, a silane coupling agent, and other additives.

[0088] Examples of thermoplastic resins include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin (such as 6-nylon and 6,6-nylon), phenoxy resin, acrylic resin, saturated polyester resin (such as PET), polyamideimide resin, fluororesin, styrene-isobutylene-styrene block copolymer, etc. These thermoplastic resins can be used alone or in combination of two or more kinds.

[0089] As the thermoplastic resin, preferably, an acrylic resin is used from the viewpoint of improving dispersibility in the thermosetting resin.

[0090] Examples of the acrylic resin include a carboxyl group-containing (meth)acrylic acid ester copolymer (preferably a carboxyl group-containing acrylic acid ester copolymer) obtained by polymerizing a monomer component including a (meth)acrylic acid alkyl ester having a linear or branched alkyl group and another monomer (copolymerizable monomer).

[0091] Examples of the alkyl group include alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, isobutyl, pentyl, and hexyl.

[0092] Examples of the other monomers include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

[0093] The lower limit of the weight average molecular weight of the thermoplastic resin is, for example, 100,000, preferably 300,000. The upper limit of the weight average molecular weight of the thermoplastic resin is, for example, 1,000,000, preferably 900,000. The weight average molecular weight is measured by gel permeation chromatography (GPC) based on a standard polystyrene equivalent value.

[0094] The proportion of the thermoplastic resin (solid content proportion) is adjusted so as not to inhibit the thermosetting of the thermosetting resin. Specifically, the lower limit of the proportion of the thermoplastic resin (solid content proportion) in the thermosetting resin composition is, for example, 1 mass%, preferably 2 mass%. The upper limit of the proportion of the thermoplastic resin (solid content proportion) in the thermosetting resin composition is, for example, 10 mass%, preferably 5 mass%.

[0095] The thermoplastic resin may be prepared by diluting it with an appropriate solvent.

[0096] Examples of the pigment include black pigments such as carbon black. The lower limit of the pigment particle size is, for example, 0.001 μm. The upper limit of the pigment particle size is, for example, 1 μm. The lower limit of the pigment ratio to the thermosetting resin composition is, for example, 0.1 mass %. The pigment particle size is the arithmetic mean diameter obtained by observing the pigment with an electron microscope. The upper limit of the pigment ratio to the thermosetting resin composition is, for example, 2 mass %.

[0097] Examples of the silane coupling agent include silane coupling agents containing an epoxy group. Examples of the silane coupling agent containing an epoxy group include 3-glycidoxydialkyldialkoxysilanes such as 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxyalkyltrialkoxysilanes such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane. Preferably, 3-glycidoxyalkyltrialkoxysilane is used. The lower limit of the content of the silane coupling agent in the thermosetting resin composition is, for example, 0.1% by mass, preferably 1% by mass. The upper limit of the content of the silane coupling agent in the thermosetting resin composition is, for example, 10% by mass, preferably 5% by mass.

[0098] To obtain this encapsulating resin sheet, the above-mentioned components are mixed in the above-mentioned ratios to prepare a thermosetting resin composition.

[0099] If necessary, a solvent (such as a ketone such as methyl ethyl ketone) is further blended to prepare a varnish. The varnish is then applied to a release sheet (not shown) and then dried by heating to produce a sealing resin sheet having a sheet shape. On the other hand, a sealing resin sheet can also be formed from the thermosetting resin composition by kneading and extrusion without preparing a varnish.

[0100] The resin sheet for sealing to be formed is in the B-stage (semi-cured state), specifically, in a state before the C-stage. That is, it is in a state before complete curing. The resin sheet for sealing is formed from the A-stage thermosetting resin composition into a B-stage sheet by heating in the above-described drying and heating in extrusion kneading.

[0101] The lower limit of the thickness of the resin sheet for sealing is, for example, 10 μm, preferably 25 μm, more preferably 50 μm. The upper limit of the thickness of the resin sheet for sealing is, for example, 3000 μm, preferably 1000 μm, more preferably 500 μm, still more preferably 300 μm, particularly preferably 100 μm.

[0102] <Multi-layer resin sheet for sealing> The resin sheet for sealing may be provided in the multi-layer resin sheet for sealing together with the second resin sheet for sealing.

[0103] The multi-layer resin sheet for sealing includes the resin sheet for sealing and the second resin sheet for sealing in this order on one side in the thickness direction. Specifically, the multi-layer resin sheet for sealing includes the resin sheet for sealing and the second resin sheet for sealing disposed on the entire surface of one side in its thickness direction. Preferably, the multi-layer resin sheet for sealing includes only the resin sheet for sealing and the second resin sheet for sealing.

[0104] The material of the second resin sheet for sealing is, for example, the same as the material (thermosetting resin composition) of the resin sheet for sealing, and preferably is the same as the material (thermosetting resin composition) of the resin sheet for sealing except that it does not contain a layered silicate compound or contains it at a low concentration (for example, 1% by mass or less).

[0105] The complex viscosity etc. (η * , Η * etc.) of the second resin sheet for sealing evaluated by the dynamic viscoelasticity measurement of temperature dispersion [1] and / or the dynamic viscoelasticity measurement of frequency dispersion [2] are not particularly limited and are appropriately set according to the use and purpose of the multi-layer resin sheet for sealing.

[0106] The lower limit of the thickness of the second sealing resin sheet is, for example, 25 μm, preferably 50 μm, more preferably 100 μm, and further preferably 150 μm. The upper limit of the thickness of the second sealing resin sheet is, for example, 1000 μm, preferably 500 μm, and more preferably 300 μm.

[0107] The encapsulating multilayer resin sheet is prepared by bonding a first encapsulating resin sheet and a second encapsulating resin sheet together.

[0108] <Electronic device package manufacturing> A method for manufacturing an electronic element package by encapsulating an electronic element, as an example of an element, with an encapsulating resin sheet will be described with reference to FIGS. 1A to 1D.

[0109] (Example of using a sealing resin sheet) In this method, first, as shown in Fig. 1A, an encapsulating resin sheet 1 is prepared. The encapsulating resin sheet 1 has one side and another side in the thickness direction that face each other in the thickness direction.

[0110] Separately, an electronic element 21 is prepared as shown in FIG. 1B.

[0111] The electronic elements 21 include electronic components, and are mounted, for example, in multiple numbers on a substrate 22. The multiple electronic elements 21 and the substrate 22 are provided on an element mounting substrate 24 together with bumps 23. In other words, the element mounting substrate 24 includes the multiple electronic elements 21, the substrate 22, and the bumps 23.

[0112] The substrate 22 has a generally flat plate shape extending in a planar direction. On one surface 25 in the thickness direction of the substrate 22, terminals (not shown) to be electrically connected to electrodes (not shown) of the electronic element 21 are provided.

[0113] Each of the electronic elements 21 has a generally flat plate shape (chip shape) extending in a planar direction. The electronic elements 21 are arranged at intervals from one another in the planar direction. The other thickness direction surfaces 28 of the electronic elements 2 are parallel to one thickness direction surface 25 of the substrate 22. An electrode (not shown) is provided on the other thickness direction surface 28 of each of the electronic elements 21. The electrode of the electronic element 21 is electrically connected to a terminal of the substrate 22 via a bump 23, which will be described next. A gap (space) 26 is provided between the other thickness direction surface 28 of the electronic element 21 and one thickness direction surface 25 of the substrate 22.

[0114] The lower limit of the distance (length in the thickness direction) between adjacent electronic elements 21 is, for example, 50 μm, preferably 100 μm, and more preferably 200 μm. The upper limit of the distance between adjacent electronic elements 21 is, for example, 10 mm, preferably 5 mm, and more preferably 1 mm.

[0115] The bumps 23 electrically connect the electrodes (not shown) of the multiple electronic elements 21 to the terminals of the substrate 22. The bumps 23 are disposed between the electrodes of the electronic elements 21 and the terminals of the substrate 22. Examples of materials for the bumps 23 include solder and metals such as gold. The thickness of the bumps 23 corresponds to the thickness (height) of the gaps 26. The thickness of the bumps 23 is set appropriately depending on the application and purpose of the element mounting substrate 24.

[0116] 1B, the encapsulating resin sheet 1 is placed on the multiple electronic elements 21. Specifically, the other surface in the thickness direction of the encapsulating resin sheet 1 is brought into contact with one surface in the thickness direction of the multiple electronic elements 21.

[0117] 1C, the encapsulating resin sheet 1 and the element mounting board 24 are pressed together. Preferably, the encapsulating resin sheet 1 and the element mounting board 24 are heat-pressed together at a low temperature.

[0118] For example, the sealing resin sheet 1 and the element mounting board 24 are sandwiched in the thickness direction and pressed by a press 27 equipped with two flat plates. Note that the flat plates of the press 27 are equipped with, for example, a heat source (not shown).

[0119] The pressing conditions (pressure, time, temperature, and the like) are not particularly limited, and conditions are selected that allow the encapsulating resin sheet 1 to enter between the plurality of electronic elements 21 while not damaging the element mounting substrate 24. More specifically, the pressing conditions are set so that a sufficient shear stress is applied to the encapsulating resin sheet 1, causing the encapsulating resin sheet 1 to flow and enter between the adjacent electronic elements 21, covering the peripheral side surfaces of each of the plurality of electronic elements 21, while contacting one surface 25 in the thickness direction of the substrate 22 that does not overlap with the electronic elements 21 in a plan view.

[0120] Specifically, the lower limit of the pressing pressure is, for example, 0.05 MPa, preferably 0.1 MPa. The upper limit of the pressing pressure is, for example, 10 MPa, preferably 5 MPa. The lower limit of the pressing time is, for example, 0.3 minutes, preferably 0.5 minutes. The upper limit of the pressing time is, for example, 10 minutes, preferably 5 minutes.

[0121] Specifically, the lower limit of the heating temperature is, for example, 40°C, or preferably 60°C. The upper limit of the heating temperature is, for example, 100°C, or preferably 95°C.

[0122] By pressing the sealing resin sheet 1 (application of shear stress), the sealing resin sheet 1 is plastically deformed in accordance with the outer shape of the electronic elements 21. The other surface in the thickness direction of the sealing resin sheet 1 is deformed into a shape corresponding to one surface in the thickness direction and peripheral side surfaces of the multiple electronic elements 21.

[0123] The above-mentioned deformation of the encapsulating resin sheet 1 due to pressing is caused by the fact that the encapsulating resin sheet 1 has high frequency dependency.

[0124] The sealing resin sheet 1 undergoes plastic deformation while maintaining the B stage.

[0125] As a result, the sealing resin sheet 1 covers the peripheral side surfaces of each of the multiple electronic elements 21, and contacts one surface 25 in the thickness direction of the substrate 22 that does not overlap with the electronic elements 21 in a plan view.

[0126] In this way, the sealing body 31 that seals the electronic element 21 is formed (produced) from the sealing resin sheet 1. One surface in the thickness direction of the sealing body 31 becomes a flat surface.

[0127] Thereafter, as shown in FIG. 1D, sealed body 31 is heated to form hardened body 41 from sealed body 31.

[0128] Specifically, the sealing body 31 and the element mounting board 24 are removed from the press 27, and then the sealing body 31 and the element mounting board 24 are heated in a dryer under atmospheric pressure.

[0129] The lower limit of the heating temperature (cure temperature) is, for example, 100° C., preferably 120° C. The upper limit of the heating temperature (cure temperature) is, for example, 200° C., preferably 180° C. The lower limit of the heating time is, for example, 10 minutes, preferably 30 minutes. The upper limit of the heating time is, for example, 180 minutes, preferably 120 minutes.

[0130] By heating the above-described sealed body 31, a C-stage (completely cured) hardened body 41 is formed from the sealed body 31. One surface in the thickness direction of the hardened body 41 is an exposed surface.

[0131] It should be noted that the edge of the sealing body 31, which has been allowed to slightly penetrate into the gap, is allowed to penetrate further slightly into the gap 26 and become the hardened body 41, but the extent to which this occurs is kept as small as possible.

[0132] The above-mentioned suppression of the intrusion of the cured body 41 is due to the fact that the sealing resin sheet 1 has low temperature dependency.

[0133] In the sealing resin sheet 1, the complex viscosity η at 50° C. * at 50℃Minimum complex viscosity η at 80℃~120℃ * MIN at 80 to 120℃ The ratio (η * MIN at 80 to 120℃ / η * at 50℃ ) is as high as 0.170 or more. In other words, the temperature dependency of the encapsulating resin sheet 1 (sealant 31) during heat curing is low. Therefore, when the encapsulating resin sheet 1 is placed on the electronic element 21, the encapsulant 31 is formed by pressing, and the encapsulant 31 is heated to form the cured body 41, it is possible to reduce the intrusion of the cured body 41 between the electronic element 21 and the substrate 22.

[0134] On the other hand, the complex viscosity at a frequency of 0.01 Hz is * at 0.01Hz Complex viscosity H at a frequency of 10 Hz * at 10Hz The ratio (H * at 10Hz / H * at 0.01Hz ) is low, at 0.0020 or less. In other words, the frequency dependency of the encapsulating resin sheet 1 during shearing (pressing) is high. Therefore, when the encapsulating resin sheet 1 is placed on the electronic element 21 and pressed, the complex viscosity of the encapsulating resin sheet 1 is sufficiently reduced based on the shearing force of the press. Therefore, the peripheral edge of the gap 26 between the electronic element 21 and the substrate 22 can be reliably sealed.

[0135] Furthermore, the second lowest complex viscosity η in the temperature range of 50℃ to 150℃ * MIN at 50 to 150℃ Since the temperature T corresponding to this is in the range of 80°C to 120°C, the encapsulating resin sheet can be made to flow sufficiently during actual use, and the curing speed of the encapsulating resin sheet does not slow down, and the curing time can be made to be about the same as in the conventional case.

[0136] Furthermore, since the ratio (G'' / G') of the loss shear modulus G'' at the above-mentioned temperature T to the storage shear modulus G' at the same temperature T is 0.4 or less, the amount of penetration of the hardened body 41 can be suppressed as much as possible at the hardening temperature T or a temperature close to the hardening temperature T.

[0137] (Example of using a multi-layer resin sheet for sealing) A method for manufacturing an electronic element cured body package 50 by encapsulating a plurality of electronic elements 21 with an encapsulating multilayer resin sheet 11 and then forming a cured body 41 will be described with reference to Figs. 2A to 2D.

[0138] 2A, a sealing multilayer resin sheet 11 is prepared. Specifically, the sealing resin sheet 1 and a second sealing resin sheet 12 are bonded together.

[0139] As shown in FIG. 2B, a plurality of electronic elements 21 to be mounted on a substrate 22 are prepared.

[0140] Next, the encapsulating multilayer resin sheet 11 is placed on the electronic element 21 so that the other surface in the thickness direction of the encapsulating resin sheet 1 contacts one surface in the thickness direction of the electronic element 21 .

[0141] As shown in FIG. 2C, thereafter, the sealing resin sheet 1 and the element mounting board 24 are pressed.

[0142] The pressing causes the encapsulating resin sheet 1 to flow and enter between the adjacent electronic elements 21. The above-mentioned deformation of the encapsulating resin sheet 1 is caused by the fact that the encapsulating resin sheet 1 has high frequency dependency.

[0143] On the other hand, the second sealing resin sheet 12 does not contain a layered silicate compound or contains it at a low concentration, so that even when pressed, its fluidity does not improve but remains low, and the infiltration of the compound between adjacent electronic elements 21 is suppressed.

[0144] As a result, a sealing body 31 for sealing the plurality of electronic elements 21 is formed from the sealing multilayer resin sheet 11 .

[0145] In addition, when the sealing resin sheet 1 contains an inorganic filler at a ratio not less than the above-mentioned lower limit and the second sealing resin sheet 12 contains an inorganic filler at a ratio not less than the above-mentioned lower limit, the sealing resin sheet 1 and the second sealing resin sheet 12 can flow by pressing as shown in the next FIG. 2C.

[0146] At this time, the encapsulating resin sheet 1 is in contact with the electronic element 21, while the second encapsulating resin sheet 12 is located on the opposite side of the electronic element 21 with respect to the encapsulating resin sheet 1. In other words, an edge of the encapsulating body 31 facing the gap 26 is formed from the encapsulating resin sheet 1. On the other hand, one surface in the thickness direction of the encapsulating body 31 is formed from the second encapsulating resin sheet 12.

[0147] Thereafter, as shown in FIG. 2D, sealed body 31 is heated to form hardened body 41 from sealed body 31.

[0148] This encapsulating multilayer resin sheet 11 can also achieve the same effects as those of the encapsulating resin sheet 1 described above.

[0149] In particular, if the encapsulating resin sheet 1 and the second encapsulating resin sheet 12 contain a base material of an epoxy resin having a softening point of 50° C. or more and 130° C. or less, the encapsulating resin sheet 1 and the second encapsulating resin sheet 12 can flow in the step shown in Fig. 2C. This allows the time for the step shown in Fig. 2C to be shortened, and allows one surface in the thickness direction of the second encapsulating resin sheet 12 to be flattened in the step shown in Fig. 2C.

[0150] Furthermore, if the sealing resin sheet 1 and the second sealing resin sheet 12 contain a phenol resin as a curing agent together with the epoxy resin as a main agent, the cured body 41 has high heat resistance and high chemical resistance. Therefore, the cured body 41 has excellent sealing reliability.

[0151] 2C, the second sealing resin sheet 12 is fluidized by the pressing force, and one surface in the thickness direction becomes flat. In addition, in the step shown in Fig. 2C, in the sealing multilayer resin sheet 11, as described above, the sealing resin sheet 1 together with the second sealing resin sheet 12 is softened and fluidized by the pressing force, and is deformed to follow the outer shape of the electronic element 21. In the step shown in Fig. 2C, the sealing resin sheet 1 is allowed to enter the gap 26 slightly.

[0152] In the step shown in FIG. 2D, the encapsulating resin sheet 1 has a complex viscosity η * Based on the decrease in the thickness, the flow is suppressed, and excessive penetration into the gap 26 is suppressed. That is, in the cured body 41 obtained by curing the encapsulating multilayer resin sheet 11 including the encapsulating resin sheet 1, the cured body penetration length Y can be reduced.

[0153] Variations In the following modifications, the same components and steps as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In addition, each modification can achieve the same effects as those in the above-described embodiment, unless otherwise specified. Furthermore, the embodiment and its modifications can be appropriately combined.

[0154] The second sealing resin sheet 12 in the sealing multilayer resin sheet 11 may be multilayered.

[0155] As an example of an element, there is mentioned an electronic element 21 arranged across a gap 26 from one surface 25 in the thickness direction of the substrate 22, which is sealed with the sealing resin sheet 1; however, for example, although not shown, there can also be mentioned an electronic element 21 in contact with one surface 25 in the thickness direction of the substrate 22, which can be sealed with the sealing resin sheet 1.

[0156] Furthermore, although the electronic element 21 has been given as an example of an element, a semiconductor element may also be given.

[0157] In addition, the ratio (H * at 10Hz / H* at 0.01Hz ) is less than 0.0020, while the ratio (η * MIN at 80 to 120℃ / η * at 50℃ ) is less than 0.170. EXAMPLES

[0158] The present invention will be described in more detail below with reference to Preparation Examples, Comparative Preparation Examples, Examples, and Comparative Examples. However, the present invention is not limited to these Preparation Examples, Comparative Preparation Examples, Examples, and Comparative Examples. In addition, specific numerical values ​​such as blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be replaced with the upper limit (a numerical value defined as "not more than" or "less than") or lower limit (a numerical value defined as "not less than" or "exceeding") of the corresponding blending ratios (content ratios), physical property values, parameters, etc. described in the above "Form for implementing the invention."

[0159] The components used in the Preparation Examples and Comparative Preparation Examples are shown below.

[0160] Layered silicate compound: Esben NX manufactured by Hojun Co., Ltd. (organic bentonite whose surface is modified with dimethyl distearyl ammonium) Base resin: YSLV-80XY manufactured by Nippon Steel Chemical Co., Ltd. (bisphenol F type epoxy resin, high molecular weight epoxy resin, epoxy equivalent 200g / eq. softening point 80℃) Hardener: Gun-ei Chemical's LVR-8210DL (novolac type phenolic resin, latent hardener, hydroxyl equivalent: 104 g / eq., softening point: 60°C) Curing accelerator: 2PHZ-PW (2-phenyl-4,5-dihydroxymethylimidazole) manufactured by Shikoku Chemical Industry Co., Ltd. Acrylic resin: HME-2006M manufactured by Negami Chemical Industries, carboxyl group-containing acrylic acid ester copolymer (acrylic polymer), weight average molecular weight: 600,000, glass transition temperature (Tg): -35°C, methyl ethyl ketone solution with solid content of 20% by mass Silane coupling agent: Shin-Etsu Chemical's KBM-403 (3-glycidoxypropyltrimethoxysilane) First filler: FB-8SM (spherical fused silica powder (inorganic filler), average particle size 7.0 μm) Second filler: Inorganic filler made by surface-treating Admatechs' SC220G-SMJ (average particle size 0.5 μm) with 3-methacryloxypropyltrimethoxysilane (product name: KBM-503 made by Shin-Etsu Chemical Co., Ltd.). Inorganic particles surface-treated with 1 part by mass of silane coupling agent per 100 parts by mass of inorganic filler. Carbon black: Mitsubishi Chemical #20, particle size 50 nm

[0161] Preparation Examples 1 to 3 and Comparative Preparation Examples 1 to 2 A varnish of a thermosetting resin composition was prepared according to the formulation shown in Table 1. The varnish was applied to the surface of a release sheet and then dried at 120° C. for 2 minutes to prepare an encapsulating resin sheet 1 having a thickness of 65 μm.

[0162] Separately, a sealing resin sheet 1 having a thickness of 25 μm was also produced as a thickness adjusting sheet.

[0163] All of these encapsulating resin sheets 1 were in the B stage.

[0164] Preparation Example 4 A varnish of a thermosetting resin composition was prepared according to the formulation shown in Table 2. The varnish was applied to the surface of a release sheet and then dried at 120° C. for 2 minutes to produce a second sealing resin sheet 12 having a thickness of 195 μm. The second sealing resin sheet 12 was in the B stage.

[0165] Examples 1 to 3 and Comparative Examples 1 to 2 In the combination of preparation examples shown in Table 3, an encapsulating resin sheet and a second encapsulating resin sheet were laminated together to prepare an encapsulating multilayer resin sheet having a thickness of 260 μm.

[0166] evaluation The following physical properties were evaluated, and the results are shown in Table 1.

[0167] A. Dynamic viscoelasticity measurement of temperature dispersion [1] The complex viscosity η of the sealing resin sheets of each preparation example and each comparative preparation example was measured by dynamic viscoelasticity measurement of temperature dispersion [1] under the following conditions. * was evaluated. Rheometer used: MARS III (rotary type), manufactured by HAAKE Temperature: 50℃~150℃ Frequency: 1Hz Heating rate: 10℃ / min Mode: Shear Distortion: 0.05% Jig: Parallel plate Distance between jigs: 800μm Sample: Fifteen sealing resin sheets with a thickness of 65 μm and one sealing resin sheet with a thickness of 25 μm were laminated in the thickness direction to make a sample sheet with a thickness of 1000 μm, which was then cut into a disk shape with a diameter of 8 mm.

[0168] In the dynamic viscoelastic measurement of this temperature dispersion [1], the complex viscosity η * at 50℃ and the minimum complex viscosity η at 80℃~120℃ * MIN at 80 to 120℃ and the second lowest complex viscosity η in the temperature range of 50℃ to 150℃ * MIN at 50 to 150℃ The temperature T corresponding to this and the loss shear modulus G'' / storage shear modulus G' were calculated.

[0169] In addition, the complex viscosity η in the dynamic viscoelasticity measurement [1] of the temperature dispersion of each of Example 1 and Comparative Example 2 * The temperature curve is shown in Figure 4.

[0170] B. Dynamic viscoelasticity measurement of frequency dispersion [2] The complex viscosity H of the encapsulating resin sheets of each preparation example and each comparative preparation example was measured by dynamic viscoelasticity measurement of frequency dispersion [2] under the following conditions. * was evaluated. Rheometer used: MARS III (rotary type), manufactured by HAAKE Temperature: 90℃ Frequency: 0.01Hz~10Hz Mode: Shear Distortion: 0.05% Jig: Parallel plate Distance between jigs: 800μm Sample: Fifteen sealing resin sheets with a thickness of 65 μm and one sealing resin sheet with a thickness of 25 μm were laminated in the thickness direction to make a sample sheet with a thickness of 1000 μm, which was then cut into a disk shape with a diameter of 8 mm.

[0171] Next, the complex viscosity H at a frequency of 0.01 Hz * at 0.01Hz Complex viscosity H at a frequency of 10 Hz * at 10Hz The ratio (H * at 10Hz / H * at 0.01Hz ) was sought.

[0172] In addition, the complex viscosity H in the dynamic viscoelasticity measurement [2] of the frequency dispersion of Example 1 and Comparative Example 2 * The frequency curve is shown in Figure 5.

[0173] (Measurement of hardened body penetration length Y) For the sealing multilayer resin sheets 11 of the respective Examples and Comparative Examples, the following steps A to E were carried out as shown in Figs. 3A to 3D, and the cured body penetration length Y was measured.

[0174] Step A: As shown in FIG. 3A, a disk-shaped sample sheet 61 having a diameter of 8 mm and a thickness of 1000 μm was prepared from the sealing resin sheet 1.

[0175] Step B: As shown in FIG. 3B, a dummy element mounting substrate 74 was prepared in which a dummy element 71 measuring 3 mm in length, 3 mm in width, and 200 μm in thickness was mounted on a glass substrate 72 via a bump 23 having a thickness of 20 μm.

[0176] Step C: As shown in FIG. 3C, the sample sheet 61 was used to seal the dummy elements 71 on the dummy element mounting substrate 74 using a vacuum platen press at a temperature of 65° C., a pressure of 0.1 MPa, a vacuum degree of 1.6 kPa, and a press time of 1 minute, thereby forming a sealed body 31 from the sample sheet 61.

[0177] Step D: As shown in FIG. 3D, sealed body 31 was thermally cured by heating at 150° C. under atmospheric pressure for 1 hour, and a cured body 41 was formed from sealed body 31.

[0178] Step E: As shown in the enlarged view of FIG. 3D, the side edge 75 of the dummy element 71 was used as a reference, and the penetration length Y of the hardened body 41 from the side edge 75 into the gap 26 between the dummy element 71 and the glass substrate 72 was measured.

[0179] The dummy element 71 has a generally flat plate shape (chip shape) extending in the planar direction.

[0180] The glass substrate 72 has a generally flat plate shape extending in the plane direction. In a region not overlapping with the bump 23 when projected in the thickness direction, a gap 26 having a thickness of 20 μm is provided between the other surface of the dummy element 71 in the thickness direction and one surface of the glass substrate 72 in the thickness direction.

[0181] The dummy element mounting board 74 includes the above-mentioned dummy elements 71, a glass substrate 72, and bumps 23.

[0182] Next, the hardened body penetration length Y was evaluated according to the following criteria. The results are shown in Table 3. ◯: The hardened body penetration length Y was 0 μm or more and 20 μm or less. Δ: The hardened body penetration length Y was more than 20 μm and 30 μm or less, or less than 0 μm and −5 μm or more. ×: The hardened body penetration length Y was more than 30 μm or less than −5 μm.

[0183] In the evaluation, "minus" means that a space (see the thick dashed line in FIG. 3D) is formed that protrudes outward from the side edge 75 of the dummy element 71. The absolute value of the "minus" corresponds to the protruding length of the space.

[0184] (Measurement of encapsulated body penetration length) For the encapsulating multilayer resin sheet 11 of each of the Examples and Comparative Examples, the following step F was further carried out between the above-mentioned steps C and D to measure the cured body penetration length Y. The results are shown in Table 3.

[0185] Step F: Using side edge 75 of dummy element 71 as a reference, the penetration length X of sealing body 31 from side edge 75 into gap 26 between dummy element 22 and glass substrate 72 was measured. ◯: The encapsulant penetration length X was 0 μm or more and 10 μm or less. △: The encapsulant penetration length X was more than 10 μm and 20 μm or less, or less than 0 μm and −5 μm or more. ×: The encapsulant penetration length X was more than 20 μm or less than −5 μm.

[0186] [Table 1]

[0187] [Table 2]

[0188] [Table 3]

[0189] The above invention is provided as an exemplary embodiment of the present invention, but this is merely an example and should not be interpreted as being limited. Modifications of the present invention that are obvious to those skilled in the art are included in the scope of the following claims. [Industrial Applicability]

[0190] The sealing resin sheet is used to seal elements. [Explanation of symbols]

[0191] 1 Sealing resin sheet 21 Electronic elements η * at 50℃ Complex viscosity at 50℃ η * MIN at 80 to 120℃ Minimum complex viscosity at 80℃~120℃ H * at 0.01Hz Complex viscosity at a frequency of 0.01 Hz H * at 10Hz Complex viscosity at a frequency of 10 Hz η * MIN at 50 to 150℃ Second lowest complex viscosity T temperature

Claims

1. a sealing resin sheet for sealing an element, the sheet comprising a thermosetting resin, a curing agent, a curing accelerator, a thermoplastic resin, a layered silicate compound, and an inorganic filler other than the layered silicate compound; the lower limit of the content of the layered silicate compound in the sealing resin sheet is more than 1 mass% and the upper limit is 25 mass%, The lower limit of the content of the inorganic filler in the sealing resin sheet is 50 mass % and the upper limit is 90 mass %, The complex viscosity η of the sealing resin sheet was measured by dynamic viscoelasticity measurement [1] of temperature dispersion under the following conditions: * Evaluate Temperature: 50℃~150℃ Frequency: 1Hz Heating rate: 10°C / min Mode: Shear Complex viscosity η at 50 ° C. * at 50℃ The minimum complex viscosity η at 80°C to 120°C * MIN at 80 to 120℃ The ratio of (η * MIN at 80 to 120℃ / * at 50℃ ) is 0.170 or more.

2. In the dynamic viscoelasticity measurement of temperature dispersion [1], the second minimum complex viscosity η in the temperature range of 50 ° C. to 150 ° C. * MIN at 50 to 150℃ The sealing resin sheet according to claim 1, wherein the temperature T corresponding to is in a range of 80°C to 120°C.

3. 3. The sealing resin sheet according to claim 2, wherein a ratio (G'' / G') of a loss shear modulus G'' to a storage shear modulus G' at the temperature T is 0.4 or less.

4. a sealing resin sheet for sealing an element, the sheet comprising a thermosetting resin, a curing agent, a curing accelerator, a thermoplastic resin, a layered silicate compound, and an inorganic filler other than the layered silicate compound; the lower limit of the content of the layered silicate compound in the sealing resin sheet is more than 1 mass% and the upper limit is 25 mass%, The lower limit of the content of the inorganic filler in the sealing resin sheet is 50 mass % and the upper limit is 90 mass %, The complex viscosity H of the sealing resin sheet was measured by dynamic viscoelasticity measurement [2] of frequency dispersion under the following conditions: * Evaluate Temperature: 90℃ Frequency: 0.01Hz to 10Hz Mode: Shear Complex viscosity at a frequency of 0.01 Hz * at ０．０１Ｈｚ Complex viscosity H at a frequency of 10 Hz * at １０Ｈｚ The ratio of (H * at 10Hz / H * at 0.01Hz ) is 0.0020 or less.

5. The complex viscosity η* of the sealing resin sheet is evaluated by a dynamic viscoelasticity measurement [1] of temperature dispersion based on the following conditions, Temperature: 50℃~150℃ Frequency: 1Hz Heating rate: 10°C / min Mode: Shear In the dynamic viscoelasticity measurement of temperature dispersion [1], the second minimum complex viscosity η in the temperature range of 50 ° C. to 150 ° C. * MIN at 50 to 150℃ The sealing resin sheet according to claim 4, wherein the temperature T corresponding to is in a range of 80°C to 120°C.

6. 6. The sealing resin sheet according to claim 5, wherein a ratio (G'' / G') of a loss shear modulus G'' to a storage shear modulus G' at the temperature T is 0.4 or less.

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