JP7545822B2 - Sealing resin sheet, sealing multilayer resin sheet and electronic element package - Google Patents

Description

The present invention relates to a sealing resin sheet and a sealing multilayer resin sheet, more specifically, to a sealing resin sheet and a sealing multilayer resin sheet including the same.

It is known that a sealing sheet containing a thermosetting resin is used to seal elements mounted on a substrate with a gap therebetween by pressing, and then the thermosetting resin is thermally cured to form a cured body from the sealing sheet (see, for example, Patent Document 1 below).

JP 2016-162909 A

In recent years, with the increasing sophistication of electronic devices, there is a demand for smaller elements. Accordingly, there is also a demand for improved dimensional accuracy of the cured body during curing. Specifically, it is required for the encapsulating sheet to align (approximate) the penetration length of the cured body that penetrates from the side edge of the element into the gap between the element and the substrate, thereby precisely controlling the effect on the characteristics of the element.

It is also necessary to reliably seal the edges of the gap to improve sealing of the element.

The penetration length usually varies depending on the thickness (length in the thickness direction) of the gap between the substrate and the element.

For example, if there is a first gap and a second gap that is thinner (narrower), the penetration length in the first gap tends to be longer than the penetration length in the second gap.

Therefore, even if the composition of the sealing sheet is adjusted to suppress the penetration length of the cured body in the second gap, the penetration length of the cured body in the first gap cannot be suppressed, resulting in the problem that the effect on the characteristics of the element corresponding to the first gap and the element corresponding to the second gap cannot be precisely controlled.

On the other hand, if the composition of the sealing sheet is adjusted so that the penetration length of the cured body in the first gap can be suppressed, the penetration length of the cured body in the second gap can be sufficiently suppressed. However, in this case, the fluidity of the sealing sheet during curing is extremely reduced, so that the edge of the second gap cannot be reliably sealed, resulting in a problem of reduced sealing ability for the element corresponding to the second gap.

The present invention provides a sealing resin sheet and a sealing multilayer resin sheet that approximate the penetration length into multiple gaps that have different thickness-wise lengths relative to a substrate, while also providing excellent sealing properties for the corresponding elements.

The present invention [1] is an encapsulating resin sheet containing a thermosetting resin for encapsulating an element, and includes an encapsulating resin sheet containing a thermosetting resin, in which a first penetration length X1 determined by the following <Test 1> and a second penetration length X2 determined by the following <Test 2> satisfy the following formula (1).

X1-X2≦30μm (1)
<Test 1>
Step A: A sample sheet having a length of 10 mm, a width of 10 mm and a thickness of 260 μm is formed from the encapsulating resin sheet.
Step B: A dummy element mounting substrate is prepared in which a dummy element having a length of 3 mm, a width of 3 mm, and a thickness of 200 μm is mounted on a glass substrate via a bump having a thickness T of 50 μm.
Step C: The dummy elements on the dummy element mounting substrate are sealed by a vacuum plate press at a temperature of 65° C., a pressure of 0.1 MPa, a degree of vacuum of 1.6 kPa, and a pressing time of 1 minute using the sample sheet. An encapsulant is formed from the sample sheet.
Step D: After step C, the sealed body is thermally cured by heating at 150° C. under atmospheric pressure for 1 hour to form a cured body from the sealed body.
Step E: After step D, a first penetration length of the hardened body from a side edge of the dummy element to the gap between the dummy element and the glass substrate is calculated based on the side edge of the dummy element. Measure the length X1.
<Test 2>
Except for changing the thickness T of the bump from 50 μm to 20 μm, step B was carried out in the same manner as in test 1, and then steps C to E were carried out to determine whether the hardened body penetrated into the gap. The second penetration length X2 is performed.

The present invention [2] includes the sealing resin sheet described in [1], in which the first penetration length X1 is 50 μm or less.

The present invention [3] includes the sealing resin sheet according to [1] or [2], in which the element is mounted on a substrate and is separated from the substrate by a plurality of gaps having different thickness-wise lengths, the element includes a first element and a second element, and the plurality of gaps include a first gap located between the first element and the substrate, and a second gap located between the second element and the substrate and having a thickness-wise length shorter than that of the first gap.

The present invention [4] includes the sealing resin sheet according to [1] or [2], characterized in that the element is mounted on a substrate, and is separated from the substrate by a plurality of gaps having different thickness-wise lengths, the substrate includes an insulating plate and a terminal disposed on one side of the insulating plate, and the plurality of gaps include a first gap located between the element and the insulating plate, and a second gap located between the element and the terminal.

The present invention [5] includes a sealing multilayer resin sheet comprising, in order in the thickness direction, the sealing resin sheet according to any one of [1] to [4], in which the sealing resin sheet contacts the element when sealing the element, and a second sealing resin sheet containing a thermosetting resin, which is located on the opposite side of the element with respect to the sealing resin sheet when sealing the element.

The encapsulating resin sheet and encapsulating multilayer resin sheet of the present invention have a first penetration length X1 and a second penetration length X2 that satisfy formula (1) (X1-X2≦30 μm). Therefore, the encapsulating resin sheet and encapsulating multilayer resin sheet can align (approximate) the penetration length of the cured body into a plurality of gaps having different thickness-wise lengths relative to the substrate, and have excellent sealing properties for elements while being able to precisely control the effect of the characteristics on the elements. Therefore, when the encapsulating resin sheet and encapsulating multilayer resin sheet of the present invention are placed on elements corresponding to gaps having different thickness-wise lengths and heated to form a cured body, the penetration amount of the cured body into these gaps can be controlled to seal the elements.

1A to 1D are step diagrams for measuring a first penetration length X1 from an encapsulating resin sheet and an encapsulating multilayer resin sheet containing the same, in which FIG. 1A shows step A of forming a sample sheet, FIG. 1B shows step B of preparing a dummy element having a gap T of 50 μm from a substrate, FIG. 1C shows step C of pressing the sample sheet and the dummy element to form an encapsulated body, and FIG. 1D shows step D of heating the encapsulated body to form a hardened body. 2A to 2D are step diagrams for measuring the second penetration length X2 from an encapsulating resin sheet and an encapsulating multilayer resin sheet containing the same, in which FIG. 2A shows step A of forming a sample sheet, FIG. 2B shows step B of preparing a dummy element having a gap T of 20 μm from the substrate, FIG. 2C shows step C of pressing the sample sheet and the dummy element to form an encapsulated body, and FIG. 2D shows step D of heating the encapsulated body to form a hardened body. 3A to 3D are process diagrams for manufacturing an electronic element package by encapsulating multiple electronic elements having different distances (T1, T2) from a substrate using an encapsulating resin sheet and a second embodiment of the encapsulating multilayer resin sheet, in which FIG. 3A shows a process for preparing a encapsulating resin sheet, FIG. 3B shows a process for preparing multiple electronic elements having different thicknesses, FIG. 3C shows a process for pressing the encapsulating resin sheet and the multiple electronic elements to form a encapsulated body, and FIG. 3D shows a process for heating the encapsulated body to form a hardened body. Figures 4A to 4D are process cross-sectional views of a modified example of one embodiment of Figures 3A to 3D, in which Figure 4A shows a process of preparing an electronic element having another surface that forms a distance to an electrode and a different distance to a substrate, Figure 4B shows a process of arranging a sealing resin sheet and a sealing multilayer resin sheet on a plurality of electronic elements, Figure 4C shows a process of pressing these to form a sealing body, and Figure 4D shows a process of heating the sealing body to form a hardened body. FIG. 5 is a plan view of a device mounting board including the electronic device shown in FIG. 4A.

<One embodiment of sealing resin sheet>
An embodiment of the encapsulating resin sheet and the encapsulating multilayer resin sheet of the present invention will be described in order.

The sealing resin sheet is a resin sheet for sealing elements (see Figures 3B and 4A). More specifically, the sealing resin sheet is a resin sheet for sealing elements (see Figures 3B and 4A) that are mounted on a substrate, have multiple gaps relative to the substrate, and have different thickness-direction lengths of the gaps (hereinafter sometimes simply referred to as thickness). The sealing resin sheet contains a thermosetting resin.

Examples of thermosetting resins include epoxy resins, silicone resins, urethane resins, polyimide resins, urea resins, melamine resins, and unsaturated polyester resins. These can be used alone or in combination of two or more.

The thermosetting resin is preferably an epoxy resin. The epoxy resin will be described in detail later in the method for producing a sealing resin sheet.

The thermosetting resin may be either before it is completely cured (including B stage or A stage) or after it is completely cured (C stage). It is preferably before it is completely cured, and more preferably it is in B stage.

[First penetration length and second penetration length]
This sealing resin sheet is subjected to each of the following <Test 1> and <Test 2>, and the first penetration length X1 obtained by <Test 1> and the second penetration length X obtained by the following <Test 2> satisfy the following formula (1).

X1-X2≦30μm (1)
<Test 1>
Step A: As shown in FIG. 1A, a sample sheet 61 having a length of 10 mm, a width of 10 mm and a thickness of 260 μm is formed from an encapsulating resin sheet.

Step B: As shown in Figure 1B, prepare a dummy element mounting substrate 74 in which a dummy element 71 measuring 3 mm in length, 3 mm in width, and 200 μm in thickness is mounted on a glass substrate 72 via a bump 23 with a thickness T of 50 μm.

Step C: As shown in FIG. 1C, the sample sheet 61 is 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 degree of vacuum of 1.6 kPa, and a press time of 1 minute, forming a sealant 31 from the sample sheet 61.

Step D: As shown in FIG. 1D, after step C, the sealed body 31 is thermally cured by heating at 150° C. under atmospheric pressure for 1 hour to form a cured body 41 from the sealed body 31.

Step E: As shown in the enlarged view of FIG. 1D, after step D, the side edge 75 of the dummy element 71 is used as a reference to measure the first penetration length X1 of the hardened body 41 penetrating from the side edge 75 into the gap 26 between the dummy element 71 and the glass substrate 72.

<Test 2>
As shown in Figures 2A to 2D, except for changing (thinning) the thickness T of the bump 23 from 50 μm to 20 μm, step B is carried out in the same manner as in test 1 above, and then steps C to E are carried out to measure the second penetration length X2 of the hardened body 41 from the side edge 75.

<Details of each step in Test 1 and Test 2>
As shown in FIG. 1A and FIG. 2A, in step A in both Test 1 and Test 2, a sample sheet 61 is prepared by cutting an encapsulating resin sheet to the above-mentioned size.

As shown in Figures 1B and 2B, in step B, in both test 1 and test 2, the dummy element 71 has a generally flat plate shape (chip shape) extending in the planar direction.

As shown in Figures 1B and 2B, in both Test 1 and Test 2, the glass substrate 72 has a generally flat shape extending in the surface direction.

In both Test 1 and Test 2, the bump 23 is disposed between the other thickness-wise surface 28 of the dummy element 71 and one thickness-wise surface 25 of the glass substrate 72.

As shown in FIG. 1B, in Test 1, the thickness T of the bump 23 is 50 μm. In Test 1, in the area that does not overlap with the bump 23 when projected in the thickness direction, a gap 26 of the same size as the thickness T (50 μm) of the bump 23 is provided between the other thickness-wise surface 28 of the dummy element 71 and one thickness-wise surface 25 of the glass substrate 72.

As shown in FIG. 2B, in Test 2, the thickness of the bump 23 is 20 μm. In Test 2, in the area that does not overlap with the bump 23 when projected in the thickness direction, a gap 26 of the same size as the thickness T20 μm of the bump 23 described above is provided between the other thickness direction surface 28 of the dummy element 71 and one thickness direction surface 25 of the glass substrate 72.

As shown in Figures 1C and 2C, in step C, the sample sheet 61 and the dummy element mounting board 74 are set and pressed by a press 27 equipped with two flat plates.

In step D, the thermosetting resin in the sample sheet 61 is thermally cured (completely cured, C stage).

In step E, the side edge 75 includes the inner edge of the dummy element 71 adjacent in the planar direction.
<Difference (X1-X2)>
The first penetration length X1 (see FIG. 1D) obtained by <Test 1> and the second penetration length X2 (see FIG. 2D) obtained by <Test 2> described below satisfy the following formula (1).

X1-X2≦30μm (1)
If the difference between X1 and X2 exceeds 30 μm, the second penetration length X2 is significantly shorter than the first penetration length X1. It is not possible to align the

This case includes at least the case (1) where the second entry length X2 itself is excessively short, and the case (2) where the first entry length X1 is excessively long even if the second entry length X2 is not excessively short.

In case (1), the formulation of the material (thermosetting resin composition) of the sealing resin sheet 1 has extremely low fluidity. Therefore, as shown by the imaginary line in the enlarged view of FIG. 2D, a large second gap (unfilled portion) is formed outside the gap 26 where the cured body 41 is not formed (filled), and therefore the sealing ability against electrons is reduced.

On the other hand, in case (2), for example, the effect on the function of the element caused by the hardened body 41 coming into contact with an electrode (not shown) provided on the other surface of the element in the thickness direction becomes large. In other words, the effect on the element cannot be precisely controlled.

The upper limit of X1-X2 (difference) is preferably 27 μm, more preferably 26 μm, even more preferably 25 μm, particularly preferably 20 μm, and most preferably 15 μm, and further preferably 15 μm, 10 μm, or 5 μm.

On the other hand, the lower limit of X1-X2 (difference) is, for example, 0 μm. Typically, in Test 1, in which the spacing T of gap 26 is 50 μm, and Test 2, in which the spacing T of gap 26 is 20 μm, Test 1 has a wider opening to the gap (edge of the gap) than Test 2. Therefore, X1-X2 (difference) is usually not less than 0 μm and satisfies the following formula (2).
0≦X1-X2≦30μm (2)
The lower limit of X1-X2 (difference) is preferably 1 μm, and more preferably 3 μm.

In this embodiment, the second entry length X2 and/or the first entry length X1 may be either a positive or negative number.

Note that the second penetration length X2 being a negative number means that a space (see the thick dashed line in FIG. 2D) is formed that protrudes outward from the side edge 75 of the dummy element 71. When the first penetration length X1 is a negative number, it is the same as when the second penetration length X2 is a negative number as described above.

Preferably, both the second penetration length X2 and the first penetration length X1 are positive numbers. If both the second penetration length X2 and the first penetration length X1 are positive numbers, no unfilled portion is formed outside the gap 26, resulting in excellent sealing properties for the element.

Specifically, the upper limit of the first penetration length X1 is, for example, 100 μm, preferably 90 μm, more preferably 75 μm, even more preferably 55 μm, particularly preferably 50 μm, and most preferably 40 μm, and further preferably 30 μm, 20 μm, or 10 μm.

If the first penetration length X1 is equal to or less than the upper limit mentioned above, the penetration of the hardened body into any of the different gaps can be suppressed, and the impact on any of the elements can be reliably suppressed.

The specific upper and lower limits of the second penetration length X2 are not particularly limited as long as they are set to satisfy the above formula (1) together with the above-mentioned first penetration length X1.

<Method of manufacturing encapsulating resin sheet>
To prepare the encapsulating resin sheet, first, a thermosetting resin is prepared. Preferably, a thermosetting resin composition containing a thermosetting resin and a layered silicate compound is prepared.

Epoxy resins, which are a suitable example of thermosetting resins, are prepared as epoxy resin compositions containing a base resin, a curing agent, and a curing accelerator.

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 multifunctional 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 types. As the base agent, preferably, bifunctional epoxy resins are used, and more preferably, bisphenol F type epoxy resins are used.

The lower limit of the epoxy equivalent of the base agent is, for example, 10 g/eq., preferably 100 g/eq. The upper limit of the epoxy equivalent of the base agent is, for example, 300 g/eq., preferably 250 g/eq.

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.

If the softening point of the base resin is equal to or higher than the lower limit described above, the sealing resin sheet 1 can flow in the process shown in FIG. 2C. This allows the time required for the process shown in FIG. 2C to be shortened, and one surface in the thickness direction of the sealing resin sheet 1 can be flattened in the process shown in FIG. 2C.

The curing agent is a latent curing agent that cures the base agent by heating. Examples of the curing agent include phenolic resins such as novolac-type phenolic resins. If the curing agent is a phenolic resin, the phenolic resin and the base agent together form a cured product that has high heat resistance and high chemical resistance. Therefore, the cured product has excellent sealing reliability.

The curing accelerator is a catalyst (thermal curing catalyst) that accelerates the curing of the base compound by heating. Examples of the curing accelerator include organic phosphorus compounds, such as imidazole compounds such as 2-phenyl-4,5-dihydroxymethylimidazole (2PHZ-PW). Imidazole compounds are preferred.

The lower limit of the content of the thermosetting resin (preferably, the epoxy resin composition) in the thermosetting resin composition (solid content) (corresponding to the encapsulating resin sheet 1 shown in FIG. 1A and FIG. 2A) is, for example, 5 mass%, preferably 15 mass%, more preferably 17 mass%. The upper limit of the content of the thermosetting resin (preferably, the epoxy resin composition) in the thermosetting resin composition (solid content) is, for example, 30 mass%, preferably 25 mass%, more preferably 20 mass%, and even more preferably 18 mass%.

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%.

The ratio of the curing agent is set to the following equivalent ratio. Specifically, the lower limit of the total of hydroxyl groups in the phenolic resin relative to 1 equivalent of epoxy groups in the base agent is, for example, 0.7 equivalents, preferably 0.9 equivalents. The upper limit of the total of hydroxyl groups in the phenolic resin relative to 1 equivalent of epoxy groups 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 per 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 per 100 parts by mass of the base agent is, for example, 80 parts by mass, preferably 60 parts by mass.

The lower limit of the number of parts of the curing accelerator per 100 parts by mass of the base agent is, for example, 0.05 parts by mass. The upper limit of the number of parts of the curing accelerator per 100 parts by mass of the base agent is, for example, 5 parts by mass.

The layered silicate compound is a flow control agent when forming an encapsulant and a hardened body (described later) in sequence from the encapsulating resin sheet. Specifically, it is a hardening flow reducer that reduces the fluidity of the hardened body when the encapsulating resin sheet is heated to form the hardened body.

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

Specific examples of layered silicate compounds include smectites such as montmorillonite, beidellite, nontronite, saponite, hectorite, sauconite, and stevensite, kaolinite, halloysite, talc, and mica. Preferably, the layered silicate compound is smectite, and more preferably, montmorillonite.

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

Organic components include organic cations (onium ions) such as ammonium, imidazolium, pyridinium, and phosphonium.

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 phosphonium include dimethyl distearyl phosphonium, distearyl phosphonium, octadecyl phosphonium, hexyl phosphonium, octyl phosphonium, 2-hexyl phosphonium, dodecyl phosphonium, and trioctyl phosphonium. The organic cations can be used alone or in combination of two or more. Ammonium is preferred, and dimethyl distearyl ammonium is more preferred.

As the organically modified layered silicate compound, preferably, organically modified smectite whose surface is modified with ammonium, more preferably, organically modified bentonite whose surface is modified with dimethyl distearyl ammonium, can be mentioned.

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

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.

The lower limit of the content of the layered silicate compound in the thermosetting resin composition (sealing resin sheet) is, for example, 0.1 mass%, preferably 0.5 mass%, more preferably 1 mass%, even more preferably 2 mass%, particularly preferably 3 mass%, particularly preferably 4 mass%, and most preferably 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 20 mass%, more preferably 15 mass%, and even more preferably 10 mass%.

If the content of the layered silicate compound is equal to or greater than the lower limit, the above formula (1) can be reliably satisfied.

The thermosetting resin composition may contain additives such as inorganic fillers other than the layered silicate compound, thermoplastic resins, pigments, silane coupling agents, and other additives.

Examples of inorganic fillers include silicate compounds other than layered silicate compounds, such as orthosilicates, sorosilicates, and inosilicates, and silicon compounds (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 is used.

The shape of the inorganic filler is not particularly limited, and examples include an approximately spherical shape, an approximately plate shape, an approximately needle shape, and an irregular shape. An approximately spherical shape is preferable.

The upper limit of the median diameter of the inorganic filler is, for example, 50 μm, preferably 20 μm, and more preferably 10 μm. The lower limit of the median diameter of the inorganic filler is, for example, 0.1 μm, and 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.

The inorganic filler may also include a first filler and a second filler having a median diameter smaller than the median diameter of the first filler.

The lower limit of the median diameter of the first filler is, for example, 1 μm, preferably 3 μm. The upper limit of the median diameter of the first filler is, for example, 50 μm, preferably 30 μm.

The upper limit of the median diameter of the second filler is, for example, 0.9 μm, preferably 0.8 μm. The lower limit of the median diameter of the second filler is, for example, 0.01 μm, preferably 0.1 μm.

The lower limit of the ratio of the median diameter of the first filler to the median diameter of the second filler is, for example, 2, preferably 5. The upper limit of the ratio of the median diameter of the first filler to the median diameter of the second filler is, for example, 50, preferably 20.

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

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

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

If the content ratio and/or the number of parts of the inorganic filler is equal to or greater than the above-mentioned lower limit, the sealing resin sheet 1 can flow in the process shown in FIG. 3C.

The lower limit of the number of parts of the layered silicate compound contained per 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 per 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, even more preferably 10 parts by mass, and especially preferably 8 parts by mass.

When the inorganic filler includes a first filler and a second filler, the lower limit of the content of the first filler in the thermosetting resin composition is, for example, 30 mass%, preferably 40 mass%, and the upper limit of the content of the first filler in the thermosetting resin composition 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.

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 nylon 6 and nylon 6,6), 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 types.

As a thermoplastic resin, an acrylic resin is preferably used from the viewpoint of improving dispersibility with the thermosetting resin.

Examples of acrylic resins include carboxyl group-containing (meth)acrylic acid ester copolymers (preferably carboxyl group-containing acrylic acid ester copolymers) obtained by polymerizing monomer components including (meth)acrylic acid alkyl esters having linear or branched alkyl groups and other monomers (copolymerizable monomers).

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

Other monomers include, for example, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

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.

The proportion of the thermoplastic resin (solid content proportion) is adjusted so as not to inhibit the thermal curing 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 %.

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

The pigment may be, for example, a black pigment 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 %.

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.

First, the above-mentioned components are mixed together to prepare a thermosetting resin composition.

If necessary, a solvent is further added in an appropriate ratio to prepare a varnish of the thermosetting resin composition. The solvent is not particularly limited, and examples thereof include ketone solvents such as acetone, and alcohol solvents such as methanol, and preferably ketone solvents.

The varnish is then applied to a release sheet (not shown) and then dried by heating to produce a sheet-shaped sealing resin sheet 1 (see Figures 1A and 2A).

It is also possible to prepare the thermosetting resin composition by kneading without adding a solvent, and then manufacture the sealing resin sheet 1 by extrusion.

This encapsulating resin sheet is in the B stage (semi-cured state), specifically, a state before the C stage. In other words, it is in a state before it is completely cured. The encapsulating resin sheet is formed into a B stage sheet from the A stage composition by heating during the drying process or heating during the kneading extrusion process described above.

The lower limit of the thickness of the encapsulating resin sheet 1 is, for example, 10 μm, preferably 25 μm, and more preferably 50 μm. The upper limit of the thickness of the encapsulating resin sheet 1 is, for example, 3000 μm, preferably 1000 μm, more preferably 500 μm, even more preferably 300 μm, and particularly preferably 100 μm.

<Manufacture of Electronic Element Packages>
Next, a method for manufacturing an electronic element package 50 by encapsulating an electronic element, as an example of an element, with an encapsulating resin sheet will be described with reference to FIGS. 3A to 3D.

In this method, as shown in FIG. 3A, first, a sealing resin sheet 1 is prepared. The sealing resin sheet 1 has one side and another side in the thickness direction that face each other in the thickness direction.

Separately, as shown in FIG. 3B, an electronic element 21 is prepared. For example, multiple electronic elements 21 are prepared.

As shown in FIG. 3B, each of the electronic elements 2 has a generally flat plate shape (chip shape) extending in the planar direction. An electrode (not shown) is provided on the other surface 28 in the thickness direction of each of the electronic elements 2. The electronic element 21 contains, for example, a known electronic material.

The gap (spacing) T between the multiple electronic elements 21 and the substrate 22 is different for each of the multiple electronic elements 21.

For example, the multiple electronic elements 21 include a first element 91 separated from the substrate 22 by a first gap T1, and a second element 92 separated from the substrate 22 by a second gap T2 that is narrower than the first gap T1.

Each of the first element 91 and the second element 92 (multiple electronic elements 21) is mounted on the substrate 22 via a first bump 31 and a second bump 32 (described next) so as to have a thickness-wise other surface 28 on which a first gap T1 and a second gap T2 are formed, respectively.

The lower limit of the ratio ( T1 / T2 ) of the first gap T1 to the second gap T2 is, for example, 1.1, preferably 1.2, more preferably 1.5, and even more preferably 2. The upper limit of the ratio ( T1 / T2 ) of the first gap T1 to the second gap T2 is, for example, 10,000, preferably 1,000, more preferably 100, and even more preferably 10.

In this embodiment, each of the electronic elements 21 has, for example, the same shape and size (planar length and thickness).

The multiple electronic elements 21 and the substrate 22 are provided on an element mounting substrate 24.

The substrate 22 has a generally flat plate shape extending in the planar direction. One thickness direction surface 25 of the substrate 22 is, for example, parallel to the other thickness direction surfaces 28 of the multiple electronic elements 21. The substrate 22 includes an insulating plate and an electrode (not shown) disposed on one surface of the insulating plate. The electrode (not shown) is electrically connected via each of the first bumps 31 and the second bumps 32.

The first bump 31 and the second bump 32 are provided corresponding to the first element 91 and the second element 92.

The first bump 31 is disposed between an electrode (not shown) of the first element 91 and a terminal (not shown) of the substrate 22. The thickness of the first bump 31 corresponds to the thickness of the first gap 81 formed between the first element 91 and the substrate 22.

The second bump 32 is disposed between an electrode (not shown) of the second element 92 and a terminal (not shown) of the substrate 22. The thickness of the second bump 32 corresponds to the thickness of the second gap 82 formed between the first element 91 and the substrate 22.

Examples of materials for the first bump 31 and the second bump 32 include solder and metals such as gold.

Next, as shown in FIG. 3B, the encapsulating resin sheet 1 is placed on the multiple electronic elements 21. Specifically, the other thickness-wise surface of the encapsulating resin sheet 1 is brought into contact with one thickness-wise surface of the multiple electronic elements 21.

Next, as shown in FIG. 3C, the sealing resin sheet 1 and the element mounting board 24 are pressed. Specifically, the sealing resin sheet 1 and the element mounting board 24 are heat-pressed.

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

The pressing conditions (pressure, time, temperature, etc.) are not particularly limited, and conditions are selected such that the sealing resin sheet 1 covers the peripheral side surfaces of each of the electronic elements 21 while not damaging the element mounting substrate 24 (electronic elements 21, first bumps 31, second bumps 32, etc.). More specifically, the pressing conditions are set such that the sealing resin sheet 1 flows outside the peripheral side surfaces of each of the electronic elements 21, covering the peripheral side surfaces of each of the electronic elements 21, while contacting one thickness direction surface 25 of the substrate 22 that does not overlap each of the electronic elements 21 in a plan view.

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.

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

When the sealing resin sheet 1 is pressed, the sealing resin sheet 1 is plastically deformed to correspond to the external shape of the multiple electronic elements 21. The other thickness-wise surface of the sealing resin sheet 1 is deformed into a shape that corresponds to one thickness-wise surface and peripheral side surface of each of the multiple electronic elements 21 and one thickness-wise surface 25 of the substrate 22 that does not overlap the multiple electronic elements 21 in a plan view.

As a result, the sealing resin sheet 1 closes the edge of the first gap 81 and the edge of the second gap 82. This allows the electronic element 21 to be sealed with excellent sealing properties.

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

As a result, the sealing resin sheet 1 covers the peripheral side surfaces of each of the multiple electronic elements 21 while contacting one thickness-wise surface 25 of the substrate 22 that does not overlap with the electronic elements 21 in a plan view.

As a result, a sealing body 31 that seals multiple electronic elements 21 is formed (produced) from the sealing resin sheet 1. One side of the sealing body 31 in the thickness direction becomes a flat surface.

At this time, although not shown, the sealing body 31 is allowed to enter slightly into the first gap 81 and the second gap 82.

Then, as shown in FIG. 3D, the sealing body 31 is heated to form a hardened body 41 from the sealing body 31.

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.

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.

By heating the sealing body 31 as described above, a C-stage (fully cured) hardened body 41 is formed from the sealing body 31. One side in the thickness direction of the hardened body 41 is an exposed surface.

The edge of the sealing body 31, which is allowed to penetrate slightly into the first gap 81 and the second gap 82, is allowed to penetrate further slightly into the gap 26 and become the hardened body 41.

In this embodiment, the first penetration length X1 and the second penetration length X2 satisfy formula (1) (X1-X2≦30 μm).

Therefore, the sealing resin sheet 1 can align (approximate) the penetration length of the cured body 41 into multiple gaps with different thickness-wise lengths relative to the substrate 22, and has excellent sealing properties for the electronic element 21 while being able to precisely control the effect of the characteristics on the electronic element 21.

More specifically, the sealing resin sheet 1 can align (approximate) the penetration length of the cured body 51 into the first gap 81 between the first element 91 and the substrate 22 and the penetration length of the cured body 51 into the second gap 82 between the second element 92 and the substrate 22, and has excellent sealing properties for the first element 91 and the second element 92 while being able to precisely control the effects on the characteristics of the first element 91 and the second element 92. In other words, it has excellent sealing properties for multiple electronic elements 21.

In addition, when the sealing resin sheet 1 is placed on each of the first elements 91 and second elements 92 corresponding to the first gaps 81 and second gaps 82 of different sizes and heated to form the hardened body 41, the amount of hardened body 41 penetrating into the first gaps 81 and second gaps 82 of different sizes can be controlled to uniformly seal the first elements 91 and second elements 92.

Therefore, it is possible to manufacture an electronic element package 50 having an electronic element 21 including a first element 91 and a second element 92 with high functionality.

<Multi-layer resin sheet for sealing>
As shown in FIG. 3A , the encapsulating resin sheet 1 may be provided on an encapsulating multilayer resin sheet 11 together with a second encapsulating resin sheet 12 .

As shown in Figures 3A to 3D, the encapsulating multilayer resin sheet 11 includes an encapsulating resin sheet 1 that contacts the multiple electronic elements 21 when encapsulating the multiple electronic elements 21, and a second encapsulating resin sheet 12 that is positioned on the opposite side of the multiple electronic elements 21 from the encapsulating resin sheet 1 when encapsulating the multiple electronic elements 21.

The encapsulating multilayer resin sheet 11 includes an encapsulating resin sheet 1 and a second encapsulating resin sheet 12 in that order on one side in the thickness direction. Specifically, the encapsulating multilayer resin sheet 11 includes an encapsulating resin sheet and a second encapsulating resin sheet 12 arranged on the entire surface of one side in the thickness direction. Preferably, the encapsulating multilayer resin sheet 11 includes only an encapsulating resin sheet 1 and a second encapsulating resin sheet 12.

The lower limit of the thickness of the second sealing resin sheet 12 is, for example, 25 μm, preferably 50 μm, more preferably 100 μm, and even more preferably 150 μm. The upper limit of the thickness of the second sealing resin sheet 12 is, for example, 1000 μm, preferably 500 μm, and more preferably 300 μm.

The sealing multilayer resin sheet 11 is prepared by bonding a sealing resin sheet and a second sealing resin sheet 12 together.

The first penetration length X1 and the second penetration length X2 obtained in <Test 1> and <Test 2> of the sealing multilayer resin sheet 11 are substantially the same as the first penetration length X1 and the second penetration length X2 obtained in <Test 1> and <Test 2> of the sealing resin sheet 1 alone.

The measurement subject of the first penetration length X1 and the second penetration length X2 obtained in each of <Test 1> and <Test 2> of the encapsulating multilayer resin sheet 11 is, for example, the hardened body of the encapsulating resin sheet 1, not the hardened body of the second encapsulating resin sheet 12.

The sealing multilayer resin sheet 11 can achieve the same effects as the sealing resin sheet 1 described above.

Furthermore, by providing the encapsulating multilayer resin sheet 11 with the second encapsulating resin sheet 12, other functions can be imparted. Examples of other functions include suppressing warping after curing.

Furthermore, in Figures 3A to 3D, multiple electronic elements 21 are encapsulated with the encapsulating multilayer resin sheet 11 and the encapsulating resin sheet 1, but this is not limited thereto, and for example, as shown in Figures 1A to 1D, a single electronic element can also be encapsulated.

If the sealing resin sheet 1 contains a filler at a ratio equal to or greater than the above-mentioned lower limit, and the second sealing resin sheet 12 contains a filler at a ratio equal to or greater 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 FIG. 3C.

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

Then, as shown in FIG. 3D, the sealing body 31 is heated to form a hardened body 41 from the sealing body 31.

This sealing multilayer resin sheet 11 can achieve the same effects as the sealing resin sheet 1 described above.

In particular, if the sealing resin sheet 1 and the second sealing resin sheet 12 contain a base resin of epoxy resin having a softening point of 50°C or more and 130°C or less, the sealing resin sheet 1 and the second sealing resin sheet 12 can flow in the process shown in Figure 3C. This allows the time for the process shown in Figure 3C to be shortened, and one surface in the thickness direction of the second sealing resin sheet 12 to be flattened in the process shown in Figure 3C.

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

3C, 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 process shown in FIG. 3C, 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 deforms to follow the external shape of the electronic element 21. In the process shown in FIG. 3C, the sealing resin sheet 1 is allowed to enter the gap 26 slightly.

In the process shown in FIG. 3D, the sealing resin sheet 1 is prevented from flowing due to a decrease in viscosity accompanying an increase in temperature, and excessive penetration into the gap 26 is prevented. That is, in the cured body 41 in which the sealing multilayer resin sheet 11 including the sealing resin sheet 1 is cured, the cured body penetration length Y can be reduced.

[Modification]
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 the modifications can be appropriately combined.

As shown in Figures 4A to 5, there may be gaps T1 and T2 of different thicknesses between the electronic element 21 and the insulating plate 20 and between the electronic element 21 and the terminal 29. The element mounting board 24 includes a first gap 81 and a second gap 82.

FIGS. 4A to 4D are process cross-sectional views along line X-X of the electronic element package shown in FIG. 5. In FIG. 4A, the components along line X-X (specifically, terminals 29 and bumps 33) are hatched, and components that are not along line X-X but are visible on one side of the plane of line X-X are drawn without hatching.

In this variant, the substrate 22 includes an insulating plate 20 and a terminal 29.

The insulating plate 20 has a generally flat plate shape extending in the surface direction.

The terminal 29 is disposed on one surface 25 in the thickness direction of the insulating plate 20. In a plan view, the terminal 29 extends along the peripheral edge of the electronic element 21. The terminal 29 has a predetermined thickness T0. A plurality of terminals 29 are disposed at intervals from one another in the planar direction. Each of the plurality of terminals 29 is provided corresponding to a respective one of the plurality of electrodes (not shown) of the electronic element 21.

The thickness T0 of the terminal 29 is thinner than the thickness T1 of the first gap 81. Specifically, the lower limit of the thickness T0 of the terminal 29 is, for example, 5 μm, preferably 15 μm. The upper limit of the thickness T0 of the terminal 29 is, for example, 100 μm, preferably 50 μm.

The terminal 29 is electrically connected to an electrode (not shown) of the electronic element 21 via a bump 33.

The bumps 33 are provided in a number corresponding to the number of terminals 29. Each of the bumps 33 is disposed between each of the electrodes (not shown) of the electronic element 21 and each of the terminals 29. The material of the bumps 33 is the same as the material of the first bumps 31 described above. The thickness T2 of the bumps 33 is the same as the thickness T2 of the second bumps 32 described above. The thickness T2 of the bumps 33 corresponds to the value (T2-T0) obtained by subtracting the thickness T0 of the terminals 29 from the thickness T1 of the first gap 81 when the one thickness-wise surface 25 of the insulating plate 20 and the other thickness-wise surface 28 of the electronic element 21 are parallel.

The second gap 82 is a gap formed by the bump 23 being interposed between the electronic element 21 and the terminal 29. Therefore, the thickness T2 of the second gap 82 is the same as the thickness T2 of the bump 33. The second gap 82 is the space between the other thickness-wise surface 28 of the electronic element 21 and the one thickness-wise surface 30 of the terminal 29. Note that the second gap 82 partially overlaps with the side edge 75 of the electronic element 21 in a plan view. In more detail, the second gap 82 is the area where the electronic element 21 and the terminal 29 overlap when projected in the thickness direction, excluding the bump 33.

The first gap 81 has a thickness T2 that is thicker than the thickness T1 of the second gap 82. The first gap 81 is connected to the second gap 82. Specifically, the thickness T2 of the first gap 81 is the total thickness of the thickness T1 of the second gap 82 and the thickness T0 of the terminal 29. The first gap 81 is between the other thickness-wise surface 28 of the electronic element 21 and the one thickness-wise surface 25 of the insulating plate 20 (a gap or a cavity). The first gap 81 is the area where the electronic element 21 and the insulating plate 20 overlap when projected in the thickness direction, excluding the terminal 29. The first gap 81 also partially overlaps with the side edge 75 of the electronic element 21.

The first gap 81 and the second gap 82 overlap the entire side edge 75 of the electronic element 21.

According to the modified example shown in Figures 4A to 5, the sealing resin sheet 1 can align (approximate) the penetration length of the cured body 51 into the first gap 81 between the electronic element 21 and the insulating plate 20 and the penetration length of the cured body 51 into the second gap 82 between the electronic element 21 and the terminal 29, and can precisely control the influence of the characteristics of the portion of one electronic element 21 corresponding to the first gap 81 and the portion corresponding to the second gap 82, while providing excellent sealing performance for the outer edge of the first gap 81 and the outer edge of the second gap 82. In other words, it provides excellent sealing performance for multiple gaps in one electronic element 21.

In addition, when the sealing resin sheet 1 is placed on an electronic element 21 having a first gap 81 and a second gap 82 of different sizes and heated to form a hardened body 41, the amount of hardened body 41 penetrating into the first gap 81 and the second gap 82 of different sizes can be controlled to uniformly seal the outside of each of the first gap 81 and the second gap 82 of the electronic element 21.

Therefore, it is possible to manufacture an electronic element package 50 that includes an electronic element 21 with high functionality.

The second sealing resin sheet 12 in the sealing multilayer resin sheet 11 may also be multilayered.

In addition, although electronic element 21 was given as an example of an element, a semiconductor element could also be mentioned.

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."

The ingredients used in the preparation examples and comparative preparation examples are listed below.

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 200 g/eq., softening point 80° C.)
Hardener: LVR-8210DL manufactured by Gun-ei Chemical Industry Co., Ltd. (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, a carboxyl group-containing acrylic acid ester copolymer (acrylic polymer), weight average molecular weight: 600,000, glass transition temperature (Tg): -30°C, methyl ethyl ketone solution with a solid content of 20% by mass. Silane coupling agent: KBM-403 (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.
First filler: FB-8SM (spherical fused silica powder (inorganic filler), average particle size 7.0 μm)
Second filler: Inorganic filler obtained by surface-treating SC220G-SMJ (average particle size 0.5 μm) manufactured by Admatechs Co., Ltd. with 3-methacryloxypropyltrimethoxysilane (product name: KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd.). Inorganic particles surface-treated with 1 part by mass of a silane coupling agent per 100 parts by mass of the inorganic filler.

Carbon black: Mitsubishi Chemical #20, particle size 50 nm

Preparation Examples 1 to 7 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 produce an encapsulating resin sheet 1 having a thickness of 65 μm. The encapsulating resin sheet 1 was in the B stage.

Preparation Example 8
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 prepare a second sealing resin sheet 12 having a thickness of 195 μm. The second sealing resin sheet 12 was in the B stage.

Examples 1 to 7 and Comparative Examples 1 and 2
In the combination of preparation examples shown in Table 3, the encapsulating resin sheet and the second encapsulating resin sheet were laminated together to prepare an encapsulating multilayer resin sheet 11 having a thickness of 260 μm.

Evaluation The above-mentioned Tests 1 and 2 were each carried out to determine the first penetration length X1 and the second penetration length X2, and then the ratio X2/X1 was calculated. The results are shown in Table 3.

The encapsulating multilayer resin sheet 11 was evaluated according to the following criteria 1 and 2.
The results are shown in Table 4.

<Criteria 1>
◯: The following formula (1) is satisfied.
×: The following formula (1) is not satisfied.
X1-X2≦30μm (1)

<Criterion 2>
◯: X1 is 50 μm or less.
◯: X1 exceeds 50 μm.

<Criterion 3>
◯: X2 is a positive number.
Δ: X2 is a negative number.

Reference Signs List 1: Sealing resin sheet 11: Sealing multilayer resin sheet 20: Insulating plate 21: Electronic element 23: Bump 26: Gap 29: Terminal 31: Sealing body 41: Hardened body 61: Sample sheet 72: Glass substrate 74: Dummy element mounting substrate 75: Side edge 81: First gap 82: Second gap 91: First element 92: Second element T1: Thickness (first gap)
T2 Thickness (second gap)
X1: First entry length X2: Second entry length

Claims (9)

A sealing resin sheet containing a thermosetting resin for sealing an element,
A sealing resin sheet, characterized in that a first penetration length X1 obtained by the following <Test 1> and a second penetration length X2 obtained by the following <Test 2> satisfy the following formula (1).
X1-X2≦30μm (1)
<Test 1>
Step A: A sample sheet having a length of 10 mm, a width of 10 mm and a thickness of 260 μm is formed from the encapsulating resin sheet.
Step B: A dummy element mounting substrate is prepared, in which a dummy element having a length of 3 mm, a width of 3 mm, and a thickness of 200 μm is mounted on a glass substrate via a bump having a thickness T of 50 μm.
Step C: The dummy elements on the dummy element mounting board are sealed with the sample sheet by vacuum platen pressing at a temperature of 65° C., a pressure of 0.1 MPa, a degree of vacuum of 1.6 kPa, and a pressing time of 1 minute to form a sealed body from the sample sheet.
Step D: After step C, the sealed body is thermally cured by heating at 150° C. under atmospheric pressure for 1 hour to form a cured body from the sealed body.
Step E: After step D, the first penetration length X1 of the hardened body penetrating from the side edge of the dummy element into the gap between the dummy element and the glass substrate is measured based on the side edge of the dummy element.
<Test 2>
Except for changing the thickness T of the bump from 50 μm to 20 μm, step B is carried out in the same manner as in test 1, and then steps C to E are carried out to carry out the second penetration length X2 by which the hardened body penetrates into the gap. The sealing resin sheet according to claim 1, characterized in that the first penetration length X1 is 50 μm or less. The element is mounted on a substrate, and a plurality of gaps having different lengths in a thickness direction are spaced apart from the substrate,
The element includes a first element and a second element,
The plurality of gaps are
a first gap located between the first element and the substrate;
3 . The sealing resin sheet according to claim 1 , further comprising: a second gap located between the second element and the substrate, the second gap having a length in a thickness direction shorter than that of the first gap. The element is mounted on a substrate, and a plurality of gaps having different lengths in a thickness direction are spaced apart from the substrate,
the substrate includes an insulating plate and a terminal disposed on one surface of the insulating plate;
The plurality of gaps are
a first gap located between the element and the insulating plate;
The sealing resin sheet according to claim 1 , further comprising: a second gap located between the element and the terminal. The encapsulating resin sheet according to any one of claims 1 to 4, which is in contact with the element when encapsulating the element;
a second sealing resin sheet containing a thermosetting resin and positioned on the opposite side of the element with respect to the sealing resin sheet when sealing the element, in the thickness direction. A substrate having one surface in a thickness direction;
a first electronic element mounted on the one surface of the substrate and spaced from the one surface of the substrate by a first gap T1;
a second electronic element mounted on the one surface of the substrate and spaced from the one surface of the substrate by a second gap T2 that is narrower than the first gap T1;
a cured product of the sealing resin sheet according to any one of claims 1 to 4, which is disposed on the one surface of the substrate and seals the first electronic element and the second electronic element;
An electronic device package comprising: A substrate having one surface in a thickness direction;
a first electronic element mounted on the one surface of the substrate and spaced from the one surface of the substrate by a first gap T1;
a second electronic element mounted on the one surface of the substrate and spaced from the one surface of the substrate by a second gap T2 that is narrower than the first gap T1;
a cured product of the sealing multilayer resin sheet according to claim 5 , which is disposed on the one surface of the substrate and seals the first electronic element and the second electronic element;
An electronic device package comprising: 8. The electronic device package according to claim 6, wherein a lower limit of a ratio (T1/T2) of the first gap T1 to the second gap T2 is 1.1. The electronic element package according to claim 6 , wherein an upper limit of a ratio (T1/T2) of the first gap T1 to the second gap T2 is 100.

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