阅读说明：本技术 密封用膜和密封结构体、以及它们的制造方法 (Sealing film, sealing structure, and methods for producing same ) 是由 渡濑裕介 野村丰 石毛纮之 铃木雅彦 于 2018-04-27 设计创作，主要内容包括：一种密封用膜的制造方法,其为含有热固性树脂和无机填充材的密封用膜的制造方法,具备：准备树脂组合物的工序,所述树脂组合物含有作为热固性树脂的反应性官能团当量大于250g/mol的树脂、和所述无机填充材；以及将树脂组合物成型为膜状的工序。(a method for producing a sealing film containing a thermosetting resin and an inorganic filler, comprising: a step of preparing a resin composition containing a resin having a reactive functional group equivalent of more than 250g/mol as a thermosetting resin and the inorganic filler; and a step of molding the resin composition into a film shape.)

1. A method for producing a sealing film containing a thermosetting resin and an inorganic filler, comprising:

A step of preparing a resin composition containing a resin having a reactive functional group equivalent of more than 250g/mol as the thermosetting resin and the inorganic filler; and

And a step of molding the resin composition into a film shape.

2. The method for producing a sealing film according to claim 1, wherein the glass transition temperature of the resin composition after curing is 80 to 180 ℃.

3. The method for producing a sealing film according to claim 1 or 2, wherein the resin having a reactive functional group equivalent of more than 250g/mol contains a resin having a reactive functional group equivalent of 300 to 410 g/mol.

4. The method for producing a sealing film according to any one of claims 1 to 3, wherein the resin composition further contains a resin having a reactive functional group equivalent of 100 to 210g/mol as the thermosetting resin.

5. The method for producing a sealing film according to any one of claims 1 to 4, wherein the resin composition further contains, as the thermosetting resin: a resin having 1/2.9 to 1/2 times the equivalent weight of the reactive functional group relative to the equivalent weight of the reactive functional group of the resin having the equivalent weight of the reactive functional group of more than 250 g/mol.

6. The method for producing a sealing film according to any one of claims 1 to 5, wherein the resin having a reactive functional group equivalent of more than 250g/mol contains an epoxy resin.

7. The method for producing a sealing film according to any one of claims 1 to 6, wherein the sealing film has a film thickness of 20 to 250 μm.

8. A sealing film comprising a thermosetting resin and an inorganic filler,

The thermosetting resin comprises a resin having a reactive functional group equivalent weight of greater than 250 g/mol.

9. The sealing film according to claim 8, wherein the glass transition temperature after curing is 80 to 180 ℃.

10. The sealing film according to claim 8 or 9, wherein the resin having a reactive functional group equivalent of more than 250g/mol comprises a resin having a reactive functional group equivalent of 300 to 410 g/mol.

11. The sealing film according to any one of claims 8 to 10, wherein the thermosetting resin further comprises a resin having a reactive functional group equivalent of 100 to 210 g/mol.

12. The sealing film according to any one of claims 8 to 11, the thermosetting resin further comprising a resin that is: a resin having 1/2.9 to 1/2 times the equivalent weight of the reactive functional group relative to the equivalent weight of the reactive functional group of the resin having the equivalent weight of the reactive functional group of more than 250 g/mol.

13. The sealing film according to any one of claims 8 to 12, wherein the resin having a reactive functional group equivalent of more than 250g/mol comprises an epoxy resin.

14. The sealing film according to any one of claims 8 to 13, which has a film thickness of 20 to 250 μm.

15. A seal structure body is provided with: a sealed body; and a cured product of the sealing film according to any one of claims 8 to 14 for sealing the sealed body.

16. A method for manufacturing a seal structure, comprising the steps of: a sealed body is sealed by using the sealing film obtained by the method according to any one of claims 1 to 7 or the sealing film according to any one of claims 8 to 14.

Technical Field

The present invention relates to a sealing film and a sealing structure, and methods for producing them.

Background

Along with the reduction in weight, size, and thickness of electronic component devices (semiconductor devices and the like), electronic devices have been reduced. A semiconductor device having substantially the same size as a semiconductor element (semiconductor chip such as a silicon chip) or a semiconductor device mounted on a semiconductor device (stacked package) is being used, and further reduction in size and thickness of an electronic component device is expected in the future.

If the miniaturization of semiconductor devices is advanced and the number of terminals is increased, it is difficult to provide all external connection terminals (terminals for external connection) on the semiconductor devices. For example, when external connection terminals are provided, the pitch between the terminals becomes narrow, and the terminal height becomes low, making it difficult to ensure connection reliability after mounting the semiconductor device. Therefore, many new mounting methods have been proposed to achieve miniaturization and thinning of the electronic component device.

For example, a mounting method has been proposed in which after semiconductor elements produced by singulating a semiconductor wafer are rearranged with an appropriate spacing, the semiconductor elements are sealed with a solid or liquid resin (sealing resin), and external connection terminals are provided at sealing portions that seal the semiconductor elements outside the semiconductor elements, and a semiconductor device produced by using the mounting method (see, for example, patent documents 1 to 3 below).

In the above mounting method, the following steps may be performed: in a sealed structure (sealed molding) produced by sealing an electronic component, a wiring for disposing an external connection terminal and the external connection terminal are formed. In the above mounting method, a plurality of electronic component devices (semiconductor devices and the like) may be obtained by dicing a sealing structure body obtained by sealing a plurality of electronic components (semiconductor elements and the like). In this case, the more electronic components to be rearranged, the more electronic component devices can be manufactured in one step. Therefore, studies have been made to enlarge the seal structure. Currently, for example, there are a downward orientation: in order to form a sealing structure into a chip shape (fan-out wafer level package) by using a semiconductor manufacturing apparatus for forming wiring, the diameter of the chip shape is increasing. Further, in order to enable a larger size and use of a printed wiring board manufacturing apparatus or the like which is cheaper than a semiconductor manufacturing apparatus, a faceting (fan-out type board level packaging) of the sealing structure body has been studied.

Disclosure of Invention

Problems to be solved by the invention

When the sealed body is sealed with the sealing resin, warpage may be a problem depending on the thermal expansion coefficient between the sealed body and the sealing portion (cured product of the sealing resin) sealing the sealed body. Especially, in a thin semiconductor device having no package substrate, such as a fan-out wafer level package and a fan-out panel level package, warpage is likely to occur.

Accordingly, an object of the present invention is to provide a sealing film capable of reducing warpage of a sealing structure, a method for producing the same, and a sealing structure using the sealing film.

Means for solving the problems

One aspect of the present invention relates to a method for producing a sealing film containing a thermosetting resin and an inorganic filler. The method comprises: a step for preparing a resin composition containing a resin having a reactive functional group equivalent of more than 250g/mol as a thermosetting resin and an inorganic filler; and a step of molding the resin composition into a film shape. According to this method, a sealing film capable of reducing warpage of a seal structure can be obtained.

The glass transition temperature of the resin composition after curing can be 80-180 ℃. In this case, a sealing film capable of improving the reliability of the sealing structure can be obtained.

The resin having a reactive functional group equivalent of more than 250g/mol may include a resin having a reactive functional group equivalent of 300 to 410 g/mol. In this case, a sealing film capable of further reducing warpage of the sealing structure can be obtained. In addition, according to this method, a sealing film having a sufficient Tg after curing and capable of improving the reliability of a sealed structure can be easily obtained.

The resin composition may further contain a resin having a reactive functional group equivalent of 100 to 210g/mol as a thermosetting resin. In this case, a sealing film capable of further reducing warpage of the sealing structure can be obtained. In addition, according to this method, a sealing film having a sufficient Tg after curing and capable of improving the reliability of a sealed structure can be easily obtained.

The resin composition may further contain, as a thermosetting resin: a resin having 1/2.9 to 1/2 times the equivalent weight of the reactive functional group relative to the equivalent weight of the reactive functional group of the resin having the equivalent weight of the reactive functional group of more than 250 g/mol. In this case, a sealing film capable of further reducing warpage of the sealing structure can be obtained. In addition, according to this method, a sealing film having a sufficient Tg after curing and capable of improving the reliability of a sealed structure can be easily obtained.

The resin having a reactive functional group equivalent weight of greater than 250g/mol may comprise an epoxy resin. In this case, a sealing film capable of further reducing warpage of the sealing structure can be obtained. In addition, according to this method, a sealing film having a sufficient Tg after curing and capable of improving the reliability of a sealed structure can be easily obtained.

The sealing film may have a film thickness of 20 to 250 μm. In this case, variation in-plane thickness during coating can be easily suppressed, and a constant drying property in the depth direction during coating can be easily obtained.

One aspect of the present invention relates to a sealing film containing a thermosetting resin and an inorganic filler, the thermosetting resin containing a resin having a reactive functional group equivalent of more than 250 g/mol. According to the sealing film, warpage of the sealing structure can be reduced.

The glass transition temperature of the sealing film after curing may be 80 to 180 ℃. In this case, the reliability of the seal structure can be improved.

The resin having a reactive functional group equivalent of more than 250g/mol may include a resin having a reactive functional group equivalent of 300 to 410 g/mol. In this case, the warpage of the seal structure can be further reduced, and the reliability of the seal structure can be improved.

The thermosetting resin may further include a resin having a reactive functional group equivalent of 100 to 210 g/mol. In this case, the warpage of the seal structure can be further reduced, and the reliability of the seal structure can be improved.

The thermosetting resin may further comprise the following resins, namely: a resin having 1/2.9 to 1/2 times the equivalent weight of the reactive functional group relative to the equivalent weight of the reactive functional group of the resin having the equivalent weight of the reactive functional group of more than 250 g/mol. In this case, the warpage of the seal structure can be further reduced, and the reliability of the seal structure can be improved.

The resin having a reactive functional group equivalent weight of greater than 250g/mol may comprise an epoxy resin. In this case, the warpage of the seal structure can be further reduced, and the reliability of the seal structure can be improved.

The sealing film may have a film thickness of 20 to 250 μm. In this case, the warpage of the seal structure can be further reduced, and the reliability of the seal structure can be improved.

One aspect of the present invention relates to a seal structure including: a sealed body, and a cured product of the sealing film for sealing the sealed body. Warpage is reduced in the seal structure.

One aspect of the present invention relates to a method for manufacturing a seal structure, including the steps of: the sealed body is sealed by using the sealing film obtained by the above method or the sealing film. According to this method, a sealed structure body with reduced warpage can be obtained.

Effects of the invention

According to the present invention, a sealing film capable of reducing warpage of a sealing structure, a method for producing the same, and a sealing structure using the sealing film can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing a sealing film with a support, which is provided with the sealing film according to the embodiment.

Fig. 2 is a schematic cross-sectional view for explaining an embodiment of a method for manufacturing a seal structure.

Fig. 3 is a schematic cross-sectional view for explaining an embodiment of a method for manufacturing a seal structure.

Detailed Description

In the present specification, a numerical range represented by "to" means a range including numerical values recited before and after "to" as a minimum value and a maximum value, respectively. In the numerical ranges recited in the present specification, the upper limit or the lower limit of the numerical range in a certain stage may be replaced with the upper limit or the lower limit of the numerical range in another stage. In the numerical ranges described in the present specification, the upper limit or the lower limit of the numerical range may be replaced with the values shown in the examples. "a or B" may include either or both of a and B. The materials exemplified in this specification may be used singly or in combination of two or more unless otherwise specified. In the present specification, the content of each component in the composition refers to the total amount of a plurality of substances present in the composition unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition.

Preferred embodiments of the present invention will be described below.

The sealing film of the present embodiment is a film-shaped resin composition containing a thermosetting component and an inorganic filler. Examples of the thermosetting component include thermosetting resins, curing agents, and curing accelerators. The thermosetting component may contain a thermosetting resin without containing a curing agent and/or a curing accelerator.

(thermosetting resin)

The thermosetting resin has 2 or more reactive functional groups in one molecule. In the present embodiment, for example, the reactive functional group and the other reactive functional group are thermally reacted to form a three-dimensional crosslinked structure, and the sealing film is cured. The other reactive functional group that reacts with the reactive functional group may be a reactive functional group of the thermosetting resin or a reactive functional group of the curing agent.

The thermosetting resin may use at least one selected from the group consisting of a thermosetting resin that is liquid at 25 ℃, and a thermosetting resin that is not liquid at 25 ℃. In the present embodiment, a thermosetting resin that is liquid at 25 ℃ is preferably used from the viewpoint of easily suppressing the occurrence of cracks and fissures on the film surface. The phrase "liquid at 25 ℃" means that the viscosity at 25 ℃ measured with an E-type viscometer is 400 pas or less.

The thermosetting resin comprises a resin A having a reactive functional group equivalent of more than 250 g/mol. In the present specification, the "reactive functional group equivalent" refers to the mass (g/mol) of the thermosetting resin relative to 1mol of the reactive functional group of the thermosetting resin. For example, when the reactive functional group is an epoxy group, the reactive functional group equivalent weight is determined as follows: after dissolving the thermosetting resin in chloroform, adding acetic acid and tetraethylammonium bromide acetic acid solution to the obtained solution, carrying out potential difference titration by using perchloric acid acetic acid standard solution, and detecting the end point of the reaction of all epoxy groups. In addition, when the reactive functional group is a hydroxyl group, the following measurement is made: adding an acetylation reagent into thermosetting resin, heating in a glycerol bath, standing, cooling, adding phenolphthalein solution as an indicator, and titrating with potassium hydroxide ethanol solution.

According to the sealing film of the present embodiment, the inclusion of the resin a can reduce warpage of the sealed structure obtained by sealing the sealed body. According to the findings of the present inventors, while warpage of the seal structure is likely to occur in a conventional sealing resin (for example, a sealing film made of a sealing resin) containing an epoxy resin and/or a phenol resin, in the present embodiment, warpage of the seal structure can be reduced even when the sealing film contains an epoxy resin and/or a phenol resin. The reason why such an effect can be obtained is not clear, but the present inventors presume that the crosslinking points at the time of curing are reduced and the crosslinking density after curing is reduced by including the resin a in the sealing film.

Examples of the resin a include epoxy resins, phenol resins, phenoxy resins, cyanate resins, thermosetting polyimides, melamine resins, urea resins, unsaturated polyesters, alkyd resins, and polyurethanes. As the resin a, an epoxy resin or a phenol resin is preferable from the viewpoint of easily obtaining a cured product having excellent thermal conductivity and from the viewpoint of remarkably improving the effect of the present invention. When the resin a is an epoxy resin, the reactive functional group is an epoxy group. When the resin a is a phenol resin, the reactive functional group is a hydroxyl group (phenolic hydroxyl group).

From the viewpoint of further reducing warpage of the sealed structure, the resin a may contain a resin having a reactive functional group equivalent of 280g/mol or more, may contain a resin having a reactive functional group equivalent of 300g/mol or more, or may contain a resin having a reactive functional group equivalent of 330g/mol or more. From the viewpoint that Tg after curing becomes sufficient and reliability (thermal reliability) of the seal structure can be improved, the resin a may contain a resin having a reactive functional group equivalent of 500g/mol or less, may contain a resin having a reactive functional group equivalent of 450g/mol or less, or may contain a resin having a reactive functional group equivalent of 410g/mol or less. From these viewpoints, the resin A may contain a resin having a reactive functional group equivalent of more than 250g/mol and 500g/mol or less, may contain a resin having a reactive functional group equivalent of 280 to 450g/mol, may contain a resin having a reactive functional group equivalent of 300 to 410g/mol, or may contain a resin having a reactive functional group equivalent of 330 to 410 g/mol.

The content of the resin a may be 5 mass% or more, 10 mass% or more, 12 mass% or more or 15 mass% or more, or 90 mass% or less, 85 mass% or less, or 70 mass% or less or 30 mass% or less, based on the total mass of the thermosetting resin, from the viewpoint of achieving both the reduction of warpage of the sealed structure and the improvement of reliability of the sealed structure. The above upper limit value and lower limit value can be arbitrarily combined. Therefore, the content of the resin a may be, for example, 10 to 90% by mass, 12 to 85% by mass, 15 to 75% by mass, 5 to 30% by mass, 10 to 30% by mass, or 15 to 30% by mass, based on the total mass of the thermosetting resin. In the following description, the upper limit value and the lower limit value described in the respective descriptions may be arbitrarily combined.

In particular, from the viewpoint of achieving both a reduction in warpage of the seal structure and an improvement in reliability of the seal structure at a higher level, the content of the resin having a reactive functional group equivalent of 300 to 410g/mol in the resin a may be 10 to 90% by mass, 12 to 85% by mass, or 15 to 75% by mass, based on the total mass of the thermosetting resin.

In the present embodiment, it is preferable to use a combination of a plurality of thermosetting resins having mutually different reactive functional group equivalents. In this case, both the reduction of warpage of the seal structure and the improvement of reliability of the seal structure can be achieved. In this case, even when the amount of the inorganic filler is increased (for example, when the amount of the inorganic filler is 70% by mass or more based on the total mass of the sealing film (excluding the mass of the solvent)), cracks and fractures after curing can be reduced. The reason why these effects can be obtained is not clear, but the present inventors speculate that the crack resistance is improved due to the crosslinked structure derived from the resin a.

The thermosetting resin preferably contains a resin B having a reactive functional group equivalent of 1/2.9 to 1/2 times relative to the reactive functional group equivalent of the resin A. In this case, both the reduction of warpage of the seal structure and the improvement of reliability of the seal structure can be achieved at a higher level. The reason for this is not clear, but the present inventors speculate that by forming a crosslinked structure having a densely crosslinked portion and a sparsely crosslinked portion by curing, stress generation can be suppressed during curing and a sufficient Tg can be secured after curing. The resin B may contain a plurality of resins having different equivalent reactive functional groups.

When the thermosetting resin contains a plurality of resins a having different reactive functional group equivalents, the resin B may be a resin having a reactive functional group equivalent of 1/2.9 to 1/2 times the reactive functional group equivalent of at least one resin a.

The reactive functional group of the resin B may be the same as or different from the reactive functional group of the resin a. The reactive functional group of the resin B may be a functional group that reacts with the reactive functional group of the resin a by heat. For example, when the resin a is an epoxy resin, the resin B may be a phenol resin, a polyamide resin, a carboxylic acid resin, or the like. For example, when the resin a is a phenol resin, the resin B may be an epoxy resin or the like.

The content of the resin B may be 5 mass% or more, 15 mass% or more, or 25 mass% or more, and may be 60 mass% or less, 50 mass% or less, or 40 mass% or less, based on the total mass of the thermosetting resin, from the viewpoint of enabling both the reduction of warpage of the seal structure and the improvement of reliability of the seal structure to be achieved at a higher level. Therefore, the content of the resin B may be, for example, 5 to 60 mass%, 15 to 50 mass%, or 25 to 40 mass% based on the total mass of the thermosetting resin.

In addition, the thermosetting resin preferably contains a resin A and a resin C having a reactive functional group equivalent of 250g/mol or less. In this case, both the reduction of warpage of the seal structure and the improvement of reliability of the seal structure can be achieved at a higher level. The reason for this is not clear, but the present inventors speculate that by forming a crosslinked structure having a densely crosslinked portion and a sparsely crosslinked portion by curing, stress generation can be suppressed during curing and a sufficient Tg can be secured after curing.

From the viewpoint of further reducing warpage of the seal structure, the resin C may contain a resin having a reactive functional group equivalent of 80g/mol or more, a resin having a reactive functional group equivalent of 90g/mol or more, a resin having a reactive functional group equivalent of 100g/mol or more, or a resin having a reactive functional group equivalent of 130g/mol or more. From the viewpoint that Tg after curing becomes sufficient and reliability (thermal reliability) of the seal structure can be improved, the resin C may contain a resin having a reactive functional group equivalent of 210g/mol or less, may contain a resin having a reactive functional group equivalent of 205g/mol or less, or may contain a resin having a reactive functional group equivalent of 160g/mol or less. From these viewpoints, the resin C may contain a resin having a reactive functional group equivalent of 80 to 250g/mol, a resin having a reactive functional group equivalent of 90 to 210g/mol, a resin having a reactive functional group equivalent of 100 to 205g/mol, a resin having a reactive functional group equivalent of 100 to 210g/mol, a resin having a reactive functional group equivalent of 100 to 160g/mol, a resin having a reactive functional group equivalent of 130 to 210g/mol, or a resin having a reactive functional group equivalent of 130 to 160 g/mol.

The resin C may contain a plurality of resins different in reactive functional group. For example, as the resin C, a resin having a reactive functional group equivalent of 100 to 160g/mol and a resin having a reactive functional group equivalent of 160 to 250g/mol may be used in combination.

The reactive functional group of the resin C may be the same as or different from the reactive functional group of the resin a. For example, the reactive functional group of the resin C may be a functional group that reacts with the reactive functional group of the resin a by heat.

The equivalent of the reactive functional group of the resin C may be 1/2.9 to 1/2 times the equivalent of the reactive functional group of the resin A. The preferable combination of the resin A and the resin C is a combination of a resin having a reactive functional group equivalent of 300 to 410g/mol and a resin having a reactive functional group equivalent of 100 to 210g/mol, and the more preferable combination is a combination of a resin having a reactive functional group equivalent of 330 to 410g/mol and a resin having a reactive functional group equivalent of 130 to 210 g/mol.

The content of the resin C may be 5 mass% or more, 15 mass% or more, 25 mass% or more, 35 mass% or more, or 45 mass% or more, and may be 85 mass% or less, 75 mass% or less, 65 mass% or less, 60 mass% or less, 50 mass% or less, or 40 mass% or less, based on the total mass of the thermosetting resin, from the viewpoint of enabling both the reduction of warpage of the seal structure and the improvement of reliability of the seal structure to be achieved at a higher level. Therefore, the content of the resin C may be, for example, 25 to 85 mass%, 35 to 75 mass%, 45 to 65 mass%, 5 to 60 mass%, 15 to 50 mass%, or 25 to 40 mass% based on the total mass of the thermosetting resin. In particular, from the viewpoint of achieving both a reduction in warpage of the seal structure and an improvement in reliability of the seal structure at a higher level, the content of the resin having a reactive functional group equivalent of 100 to 210g/mol in the resin C may be 25 to 85 mass%, 35 to 75 mass%, or 45 to 65 mass% based on the total mass of the thermosetting resin.

Next, embodiment 1 in which the resin a contains an epoxy resin and embodiment 2 in which the resin a contains a phenol resin will be described in detail.

[ embodiment 1]

In the sealing film according to embodiment 1, the resin a contains an epoxy resin. The epoxy resin having a reactive functional group equivalent of more than 250g/mol is not particularly limited as long as it has 2 or more epoxy groups in one molecule and an epoxy group equivalent of more than 250 g/mol.

Examples of the epoxy resin having a reactive functional group equivalent of more than 250G/mol include bisphenol A type epoxy resin, bisphenol AP type epoxy resin, bisphenol AF type epoxy resin, bisphenol B type epoxy resin, bisphenol BP type epoxy resin, bisphenol C type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, bisphenol G type epoxy resin, bisphenol M type epoxy resin, bisphenol S type epoxy resin (hexanediol bisphenol S diglycidyl ether, etc.), bisphenol P-type epoxy resins, bisphenol PH-type epoxy resins, bisphenol TMC-type epoxy resins, bisphenol Z-type epoxy resins, phenol novolac-type epoxy resins (o-cresol novolac-type epoxy resins and the like), biphenyl-type epoxy resins, naphthalene-type epoxy resins, dicyclopentadiene-type epoxy resins, biphenol-type epoxy resins (biphenol diglycidyl ether and the like), hydrogenated bisphenol a-type epoxy resins (hydrogenated bisphenol a glycidyl ether and the like); a dibasic acid-modified diglycidyl ether type epoxy resin of these resins; aliphatic epoxy resins, and the like. Among them, an epoxy resin having a bisphenol a skeleton is preferable from the viewpoint of satisfying both the reduction of warpage of the seal structure and the improvement of reliability of the seal structure. One kind of the epoxy resin may be used alone, or two or more kinds may be used in combination.

From the viewpoint of easily suppressing the occurrence of cracks and fissures on the film surface, as the epoxy resin having a reactive functional group equivalent of more than 250g/mol, an epoxy resin that is liquid at 25 ℃ (liquid epoxy resin) can be used. As the liquid epoxy resin, there can be mentioned: bisphenol a type glycidyl ether, bisphenol AD type glycidyl ether, bisphenol S type glycidyl ether, bisphenol F type glycidyl ether, hydrogenated bisphenol a type glycidyl ether, ethylene oxide adduct bisphenol a type glycidyl ether, propylene oxide adduct bisphenol a type glycidyl ether, naphthalene resin glycidyl ether, 3-functional or 4-functional glycidyl amine, and the like.

From the viewpoint of further reducing warpage of the seal structure, the reactive functional group equivalent of the epoxy resin having a reactive functional group equivalent of more than 250g/mol is preferably not less than 280g/mol, more preferably not less than 300g/mol, and still more preferably not less than 330 g/mol. From the viewpoint that Tg after curing becomes sufficient and reliability (thermal reliability) of the seal structure can be improved, the reactive functional group equivalent of the epoxy resin having a reactive functional group equivalent of more than 250g/mol is preferably 500g/mol or less, more preferably 450g/mol or less, and still more preferably 410g/mol or less. From such a viewpoint, the reactive functional group equivalent of the epoxy resin having a reactive functional group equivalent of more than 250g/mol is preferably more than 250g/mol and 500g/mol or less, more preferably 280 to 450g/mol, still more preferably 300 to 410g/mol, and particularly preferably 330 to 410 g/mol.

As commercially available epoxy resins having a reactive functional group equivalent of more than 250g/mol, "EXA 4816", "EXA 4850-1000" and "EXA 4850-150" manufactured by DIC K.K..

From the viewpoint of achieving both the reduction in warpage of the sealed structure and the improvement in reliability of the sealed structure, the content of the epoxy resin having a reactive functional group equivalent of more than 250g/mol may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, or 90% by mass or less, or 85% by mass or less, or 75% by mass or less, based on the total mass of the thermosetting resin. Accordingly, the content of the epoxy resin having a reactive functional group equivalent of more than 250g/mol may be, for example, 5 to 90% by mass, 10 to 85% by mass, or 15 to 75% by mass based on the total mass of the thermosetting resin. In particular, from the viewpoint of achieving both a reduction in warpage of the seal structure and an improvement in reliability of the seal structure at a higher level, the content of the epoxy resin having a reactive functional group equivalent of 300 to 410g/mol may be 5 to 90% by mass, 10 to 85% by mass, or 15 to 75% by mass, based on the total mass of the thermosetting resin.

The content of the liquid epoxy resin having a reactive functional group equivalent of more than 250g/mol may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, or 90% by mass or less, or 85% by mass or less, or 75% by mass or less, based on the total mass of the thermosetting resin. Therefore, the content of the liquid epoxy resin having a reactive functional group equivalent of more than 250g/mol may be, for example, 5 to 90% by mass, 10 to 85% by mass, or 15 to 75% by mass based on the total mass of the thermosetting resin. If the content of the liquid epoxy resin having a reactive functional group equivalent of more than 250g/mol is greater than or equal to the above lower limit value, the generation of cracks and fissures on the film surface is easily suppressed. In addition, if the content of the liquid epoxy resin having a reactive functional group equivalent of more than 250g/mol is less than or equal to the above upper limit value, excessive increase in the viscosity of the film and edge fusion are easily suppressed.

The thermosetting resin can comprise an epoxy resin having a reactive functional group equivalent of less than or equal to 250 g/mol. Examples of the epoxy resin having a reactive functional group equivalent of 250g/mol or less include: bisphenol a type epoxy resin, bisphenol AP type epoxy resin, bisphenol AF type epoxy resin, bisphenol B type epoxy resin, bisphenol BP type epoxy resin, bisphenol C type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, bisphenol G type epoxy resin, bisphenol M type epoxy resin, bisphenol S type epoxy resin (hexanediol bisphenol S diglycidyl ether, etc.), bisphenol P type epoxy resin, bisphenol PH type epoxy resin, bisphenol TMC type epoxy resin, bisphenol Z type epoxy resin, phenol novolac type epoxy resin (o-cresol novolac type epoxy resin, etc.), biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, biscresol type epoxy resin (biscresol diglycidyl ether, etc.), hydrogenated bisphenol a type epoxy resin (hydrogenated bisphenol a glycidyl ether, etc.); a dibasic acid-modified diglycidyl ether type epoxy resin of these resins; aliphatic epoxy resins, and the like. The epoxy resin having a reactive functional group equivalent of 250g/mol or less may be used alone or in combination of two or more.

From the viewpoint of easily obtaining excellent fluidity, the content of the entire epoxy resin contained in the sealing film may be 1% by mass or more, 3% by mass or more, 4% by mass or more, 5% by mass or more, 10% by mass or more, or 15% by mass or more, based on the total mass of the sealing film (excluding the mass of the solvent). The content of the entire epoxy resin contained in the sealing film may be 30% by mass or less, 25% by mass or less, or 20% by mass or less, based on the total mass of the sealing film (excluding the mass of the solvent), from the viewpoint of easily suppressing the occurrence of cracks and fissures on the film surface. Therefore, the content of the total epoxy resin contained in the sealing film may be, for example, 1 to 30% by mass based on the total mass of the sealing film (excluding the mass of the solvent).

The thermosetting resin may further comprise a resin having a functional group that reacts with the epoxy resin having a reactive functional group equivalent of more than 250g/mol using heat. For example, the thermosetting resin preferably contains a phenol resin. As the phenol resin, any known phenol resin can be used without particular limitation as long as it has 2 or more phenolic hydroxyl groups in one molecule.

Examples of the phenolic resin include: resins obtained by condensation or co-condensation of phenols and/or naphthols and aldehydes under an acidic catalyst, biphenyl skeleton-type phenol resins, p-xylene-modified phenol resins, m-xylene/p-xylene-modified phenol resins, melamine-modified phenol resins, terpene-modified phenol resins, dicyclopentadiene-modified phenol resins, cyclopentadiene-modified phenol resins, polycyclic aromatic ring-modified phenol resins, xylene-modified naphthol resins, and the like. Examples of the phenols include phenol, substituted phenol, cresol, xylenol, resorcinol, catechol, bisphenol a, and bisphenol F. Examples of the naphthol include α -naphthol, β -naphthol, and dihydroxynaphthalene. Examples of the aldehydes include formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde.

From the viewpoint of achieving both a reduction in warpage of a seal structure and an improvement in reliability of the seal structure at a higher level, the reactive functional group equivalent of the phenolic resin may be 1/2.9 to 1/2 times as large as that of the epoxy resin having a reactive functional group equivalent of more than 250 g/mol.

From the viewpoint of achieving both a reduction in warpage of a sealed structure and an improvement in reliability of the sealed structure at a higher level, the content of the phenolic resin having a reactive functional group equivalent of 1/2.9 to 1/2 times the reactive functional group equivalent of the epoxy resin having a reactive functional group equivalent of more than 250g/mol may be 15 mass% or more, 20 mass% or more or 25 mass% or more, and may be 95 mass% or less, 90 mass% or less or 85 mass% or less, based on the total mass of the thermosetting resin. Therefore, the content of the phenol resin may be, for example, 15 to 95% by mass, 20 to 90% by mass, or 25 to 85% by mass based on the total mass of the thermosetting resin.

The reactive functional group equivalent of the phenol resin may be 250g/mol or less from the viewpoint of enabling a reduction in warpage of the seal structure and an improvement in reliability of the seal structure to be compatible at a higher level. From the viewpoint of further reducing warpage of the seal structure, the reactive functional group equivalent of the phenol resin may be 210g/mol or less, 205g/mol or less, or 160g/mol or less. The reactive functional group equivalent of the phenol resin may be 80g/mol or more, 90g/mol or more, or 100g/mol or more from the viewpoint that Tg after curing becomes sufficient and reliability (thermal reliability) of the seal structure can be improved. Therefore, the equivalent weight of the reactive functional group of the phenolic resin can be, for example, 80 to 250g/mol, 90 to 210g/mol, 100 to 205g/mol, 100 to 160g/mol, 130 to 210g/mol, or 130 to 160 g/mol.

The thermosetting resin may comprise a plurality of phenolic resins having different equivalent reactive functional groups. For example, the thermosetting resin may include a phenolic resin having a reactive functional group equivalent of 100 to 160g/mol and a phenolic resin having a reactive functional group equivalent of 160 to 250 g/mol.

The phenolic resin having a reactive functional group equivalent of 250g/mol or less includes, for example, a phenolic resin having a structural unit represented by the following formula (1).

[ solution 1]

[ in the formula (1), R¹Represents a hydrocarbon group having 2 to 25 carbon atoms. When there are a plurality of structural units represented by the formula (1), a plurality of R¹Each may be the same or different. With respect to R¹The position of (a) may be any of ortho-, meta-or para-positions with respect to-OH, with respect to the bonding (— and-CH)₂-) may be any of ortho, meta or para with respect to-OH.]

R¹The hydrocarbon group represented by the formula (I) may be linear or branched. The hydrocarbon group may be either saturated or unsaturated. When the hydrocarbon group is an unsaturated hydrocarbon group, the unsaturated hydrocarbon group may have 2 or more unsaturated bonds. The number of carbon atoms of the hydrocarbon group may be 4 to 22, 8 to 20, or 10 to 18.

The phenol resin having the structural unit represented by the formula (1) may be composed of only the structural unit represented by the formula (1), or may further have a structural unit other than the structural unit represented by the formula (1). The phenol resin may be, for example, a random copolymer of the structural unit represented by the formula (1) and another structural unit, or a random copolymer including a block containing the structural unit represented by the formula (1) and a block containing another structural unit.

Examples of the other structural unit include a structural unit represented by the following formula (2).

[ solution 2]

[ in the formula (2), R²Represents a hydrogen atom or a phenyl group. When there are a plurality of structural units represented by the formula (2), a plurality of R²Each may be the same or different. With respect to R²The position of (a) may be any of ortho-, meta-or para-positions with respect to-OH, with respect to the bonding (— and-CH)₂-) may be any of ortho, meta or para with respect to-OH.]

The content of the structural unit represented by the formula (1) in the phenolic resin may be 20 to 100 mol%, 30 to 90 mol%, or 40 to 80 mol% based on the total amount of the structural units constituting the phenolic resin.

The content of the structural unit represented by the formula (2) in the phenolic resin may be more than 0 mol% and 80 mol% or less, 10 to 70 mol% or 20 to 60 mol% based on the total amount of the structural units constituting the phenolic resin.

The phenol resin having the structural unit represented by the above formula (1) can be obtained by, for example, reacting a substituted phenol represented by the following formula (3), formaldehyde, and optionally a substituted phenol represented by the following formula (4). R in the following formula (3)¹Examples of (2) and R in the above formula (1)¹In the same manner as in the case of (4), R in the following formula²Examples of (3) and R in the above formula (2)²The same applies to the example of (1).

[ solution 3]

[ solution 4]

From the viewpoint of achieving both a reduction in warpage of a sealed structure and an improvement in reliability of the sealed structure at a higher level, the content of the phenolic resin having a reactive functional group equivalent of 250g/mol or less may be 15% by mass or more, 20% by mass or more, or 25% by mass or less, or 95% by mass or less, 90% by mass or less, or 85% by mass or less, based on the total mass of the thermosetting resin. Therefore, the content of the phenolic resin having a reactive functional group equivalent of 250g/mol or less may be, for example, 15 to 95% by mass, 20 to 90% by mass, or 25 to 85% by mass based on the total mass of the thermosetting resin. In particular, from the viewpoint of achieving both a reduction in warpage of the seal structure and an improvement in reliability of the seal structure at a higher level, the content of the phenolic resin having a reactive functional group equivalent of 100 to 210g/mol may be 15 to 95% by mass, 20 to 90% by mass, or 25 to 85% by mass, based on the total mass of the thermosetting resin.

The content of the entire phenolic resin contained in the sealing film may be appropriately set in consideration of the content of the epoxy resin and the epoxy equivalent of the epoxy resin. From the viewpoint of being less likely to leave unreacted epoxy resin and/or unreacted phenol resin and easily obtaining desired cured product characteristics, the ratio (M2/M1) of the number of moles M2 of epoxy groups to the number of moles M1 of phenolic hydroxyl groups in the sealing film may be 0.7 or more, 0.8 or more, or 0.9 or more, and further, may be 2.0 or less, 1.8 or less, or 1.7 or less. Therefore, the ratio (M2/M1) of the number of moles M2 of epoxy groups to the number of moles M1 of phenolic hydroxyl groups in the sealing film may be, for example, 0.7 to 2.0, 0.8 to 1.8, or 0.9 to 1.7.

[ 2 nd embodiment ]

In the sealing film according to embodiment 2, the resin a contains a phenol resin. The phenolic resin having a reactive functional group equivalent of more than 250g/mol may be any known phenolic resin without any particular limitation as long as it has 2 or more phenolic hydroxyl groups in one molecule and a phenolic hydroxyl group equivalent of more than 250 g/mol.

Examples of the phenolic resin include: resins obtained by condensation or co-condensation of phenols and/or naphthols and aldehydes under an acidic catalyst, biphenyl skeleton-type phenol resins, p-xylene-modified phenol resins, m-xylene/p-xylene-modified phenol resins, melamine-modified phenol resins, terpene-modified phenol resins, dicyclopentadiene-modified phenol resins, cyclopentadiene-modified phenol resins, polycyclic aromatic ring-modified phenol resins, xylene-modified naphthol resins, and the like. One kind of the phenolic resin may be used alone, or two or more kinds may be used in combination.

From the viewpoint of reducing the crosslinking point and reducing the warpage, the phenolic resin having a reactive functional group equivalent of more than 250g/mol may have a reactive functional group equivalent of more than 250g/mol and 500g/mol or less, 280 to 450g/mol, 300 to 410g/mol, or 330 to 410 g/mol.

The content of the phenolic resin having a reactive functional group equivalent of more than 250g/mol may be 5 to 85 mass%, 10 to 80 mass%, or 15 to 75 mass% based on the total mass of the thermosetting resin, from the viewpoint of satisfying both the reduction of warpage of the sealed structure and the improvement of reliability of the sealed structure. In particular, from the viewpoint of achieving both a reduction in warpage of the seal structure and an improvement in reliability of the seal structure at a higher level, the content of the phenolic resin having a reactive functional group equivalent of 300 to 410g/mol may be 5 to 85 mass%, 10 to 80 mass%, or 15 to 75 mass% based on the total mass of the thermosetting resin.

The thermosetting resin can comprise a phenolic resin having a reactive functional group equivalent of less than or equal to 250 g/mol.

The content of the entire phenol resin contained in the sealing film may be 15 to 95% by mass, 20 to 90% by mass, or 25 to 85% by mass based on the total mass of the sealing film (excluding the mass of the solvent), from the viewpoint of easily obtaining excellent fluidity, and from the viewpoint of easily suppressing the occurrence of cracks and cracks on the film surface.

The thermosetting resin may further comprise a resin having functional groups that react with the phenolic resin having a reactive functional group equivalent weight of greater than 250g/mol using heat. For example, the thermosetting resin preferably contains an epoxy resin. As the epoxy resin, any known epoxy resin can be used without particular limitation as long as it has 2 or more epoxy groups in one molecule.

As the epoxy resin, the above-mentioned epoxy resins as an epoxy resin having a reactive functional group equivalent of more than 250g/mol and an epoxy resin having a reactive functional group equivalent of 250g/mol or less can be used.

From the viewpoint of achieving both a reduction in warpage of a seal structure and an improvement in reliability of the seal structure at a higher level, the reactive functional group equivalent of the epoxy resin may be 1/2.9 to 1/2 times as large as that of the phenol resin having a reactive functional group equivalent of more than 250 g/mol.

From the viewpoint of achieving both a reduction in warpage of a seal structure and an improvement in reliability of the seal structure at a higher level, the content of the epoxy resin having a reactive functional group equivalent of 1/2.9 to 1/2 times the reactive functional group equivalent of the phenolic resin having a reactive functional group equivalent of more than 250g/mol may be 15 to 95% by mass, 20 to 90% by mass, or 25 to 85% by mass based on the total mass of the thermosetting resin.

The reactive functional group equivalent of the epoxy resin may be 250g/mol or less from the viewpoint of enabling a reduction in warpage of the seal structure and an improvement in reliability of the seal structure to be compatible at a higher level. The reactive functional group equivalent of the epoxy resin may be 80 to 250g/mol, 90 to 210g/mol, 100 to 205g/mol, or 100 to 160g/mol, from the viewpoint of further reducing warpage of the sealing structure.

The content of the epoxy resin having a reactive functional group equivalent of 250g/mol or less may be 15 to 95% by mass, 20 to 90% by mass, or 25 to 85% by mass based on the total mass of the thermosetting resin, from the viewpoint of achieving both a reduction in warpage of the seal structure and an improvement in reliability of the seal structure at a higher level.

The content of the total epoxy resin contained in the sealing film may be appropriately set in consideration of the content of the phenolic resin and the phenolic hydroxyl group equivalent of the phenolic resin. The range of the ratio of the number of moles M2 of epoxy groups to the number of moles M1 of phenolic hydroxyl groups in the sealing film may be the same as that exemplified in embodiment 1.

(curing agent)

The sealing film of the present embodiment may contain a curing agent (excluding components belonging to the thermosetting resin) as a thermosetting component. The curing agent is not particularly limited, and examples thereof include a phenol-based curing agent, an acid anhydride-based curing agent, an active ester-based curing agent, and a cyanate ester-based curing agent. When the thermosetting resin contains an epoxy resin, the curing agent is not particularly limited as long as it is a compound having 2 or more functional groups reactive with an epoxy group in one molecule. When the thermosetting resin contains a phenol resin, the curing agent is not particularly limited as long as it is a compound having 2 or more functional groups that react with phenolic hydroxyl groups in one molecule. One curing agent may be used alone, or two or more curing agents may be used in combination. When the thermosetting resin contains a plurality of resins having different reactive functional groups, a plurality of curing agents may be used in combination depending on the kind of the reactive functional group.

From the viewpoint of excellent curability of the thermosetting resin, the content of the curing agent may be 1 to 20% by mass, 2 to 15% by mass, or 3 to 10% by mass based on the total mass of the sealing film (excluding the mass of the solvent).

(curing accelerators)

The sealing film of the present embodiment may contain a curing accelerator as a thermosetting component. The curing accelerator may be used without particular limitation, and is preferably at least one selected from the group consisting of amine-based curing accelerators and phosphorus-based curing accelerators. The curing accelerator is preferably an amine-based curing accelerator, more preferably at least one selected from the group consisting of imidazole compounds, aliphatic amines and alicyclic amines, and even more preferably an imidazole compound, from the viewpoint of easily obtaining a cured product having excellent thermal conductivity, abundance of derivatives, and easily obtaining a desired active temperature. Examples of the imidazole compound include 2-phenyl-4-methylimidazole and 1-benzyl-2-methylimidazole. The curing accelerator may be used alone or in combination of two or more. Commercially available products of the curing accelerator include "2P 4 MZ" and "1B 2 MZ" manufactured by national chemical industries co.

The content of the curing accelerator is preferably in the following range based on the total amount of the thermosetting resin. The content of the curing accelerator is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and still more preferably 0.3% by mass or more, from the viewpoint of easily obtaining a sufficient curing accelerating effect. The content of the curing accelerator is preferably 5% by mass or less, more preferably 3% by mass or less, and still more preferably 1.5% by mass or less, from the viewpoint that curing is not easily performed in the steps (for example, coating and drying) in the production of the sealing film or in the storage of the sealing film, and cracking of the sealing film and molding defects associated with an increase in melt viscosity are easily prevented. From these viewpoints, the content of the curing accelerator is preferably 0.01 to 5% by mass, more preferably 0.1 to 3% by mass, and still more preferably 0.3 to 1.5% by mass.

(inorganic Filler)

The inorganic filler is not particularly limited, and conventionally known inorganic fillers can be used. Examples of the constituent material of the inorganic filler include: silica (amorphous silica, crystalline silica, fused silica, spherical silica, synthetic silica, hollow silica, etc.), barium sulfate, barium titanate, talc, clay, mica powder, magnesium carbonate, calcium carbonate, alumina (aluminum oxide), aluminum hydroxide, magnesium oxide, magnesium hydroxide, silicon nitride, aluminum borate, boron nitride, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, etc. The inorganic filler containing silica is preferable from the viewpoint of easily obtaining the effect of improving dispersibility in the resin composition and the effect of suppressing sedimentation in the varnish by surface modification (for example, surface treatment with a silane compound) or the like, and from the viewpoint of easily obtaining desired cured film characteristics because of having a small thermal expansion coefficient. From the viewpoint of obtaining high thermal conductivity, an inorganic filler containing alumina is preferable. One kind of the inorganic filler may be used alone, or two or more kinds may be used in combination.

The inorganic filler may be surface-modified. The method of surface modification is not particularly limited. Surface modification using a silane coupling agent is preferable from the viewpoint of easy handling, abundant functional group types, and easiness of imparting desired characteristics.

Examples of the silane coupling agent include: alkylsilanes, alkoxysilanes, vinylsilanes, epoxysilanes, aminosilanes, acrylic silanes, methacrylic silanes, mercaptosilanes, thioether silanes, isocyanate silanes, sulfur silanes, styrylsilanes, alkylchlorosilanes, and the like.

Specific examples of the silane coupling agent include: methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, methyltriphenoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, diisopropyldimethoxysilane, isobutyltrimethoxysilane, diisobutyldimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, n-dodecylmethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, triphenylsilanol, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, n-octyldimethylchlorosilane, tetraethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropylmethyldimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, bis (3- (triethoxysilyl) propyl) disulfide, bis (3- (triethoxysilyl) propyl) tetrasulfide, vinyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, allyltrimethoxysilane, diallyldimethylsilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, glycidylmethoxysilane, glycidylmethane, 3-methacryloxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, N- (1, 3-dimethylbutylidene) -3-aminopropyltriethoxysilane, aminosilanes (such as phenylaminosilane) and the like. One kind of silane coupling agent may be used alone, or two or more kinds may be used in combination.

From the viewpoint of easily suppressing aggregation of the inorganic filler and easily dispersing the inorganic filler, the average particle diameter of the inorganic filler is preferably not less than 0.01. mu.m, more preferably not less than 0.1. mu.m, still more preferably not less than 0.3. mu.m, and particularly preferably not less than 0.5. mu.m. From the viewpoint of easily suppressing the sedimentation of the inorganic filler in the varnish and easily producing a homogeneous sealing film, the average particle diameter of the inorganic filler is preferably 25 μm or less, more preferably 10 μm or less, and still more preferably 5 μm or less. From these viewpoints, the average particle diameter of the inorganic filler is preferably 0.01 to 25 μm, more preferably 0.01 to 10 μm, still more preferably 0.1 to 10 μm, particularly preferably 0.3 to 5 μm, and most preferably 0.5 to 5 μm. The inorganic filler may have an average particle diameter of 10 to 18 μm.

From the viewpoint of excellent flowability of the resin composition, it is preferable to use a combination of a plurality of inorganic fillers having different average particle diameters from each other. In the combination of the inorganic fillers, the maximum average particle diameter is preferably 15 to 25 μm. Preferably, an inorganic filler having an average particle diameter of 15 to 25 μm, an inorganic filler having an average particle diameter of 0.5 to 2.5 μm and an inorganic filler having an average particle diameter of 0.1 to 1.0 μm are used in combination.

The "average particle diameter" is a particle diameter at a point corresponding to 50% by volume when a cumulative particle size distribution curve based on the particle diameter is obtained with the total volume of the particles being 100%, and can be measured by a particle size distribution measuring apparatus using a laser diffraction scattering method or the like. The average particle diameter of each inorganic filler to be combined can be confirmed from the average particle diameter of each inorganic filler at the time of mixing, and can be confirmed by measuring the particle size distribution.

Commercially available inorganic fillers include: "DAW 20" manufactured by Denka corporation, and "SC 5500-SXE" and "SC 2050-KC" manufactured by Admatechs corporation.

The content of the inorganic filler may be 70% by mass or more, 75% by mass or more, or 80% by mass or more based on the total mass of the sealing film (excluding the mass of the solvent), from the viewpoint of improving the thermal conductivity and easily suppressing the increase in warpage of the sealing structure (for example, an electronic component device such as a semiconductor device) due to the difference in thermal expansion coefficient from the sealed body. The content of the inorganic filler may be 93% by mass or less, 91% by mass or less, or 88% by mass or less, based on the total mass of the sealing film (excluding the mass of the solvent), from the viewpoints of easily suppressing cracking of the sealing film in a drying step when the sealing film is produced, suppressing a decrease in fluidity of the sealing film due to an increase in melt viscosity, and easily sealing a sealed body (electronic component or the like) sufficiently. From these viewpoints, the content of the inorganic filler may be 70 to 93% by mass, 75 to 91% by mass, or 80 to 88% by mass based on the total mass of the sealing film (excluding the mass of the solvent). The content is the content of the inorganic filler excluding the amount of the surface treatment agent.

(Elastomers)

The sealing film of the present embodiment may contain an elastomer (a flexibility agent) as necessary. From the viewpoint of excellent dispersibility and solubility, the elastomer is preferably at least one selected from the group consisting of polybutadiene particles, styrene butadiene particles, acrylic elastomers, silicone powder, silicone oil, and silicone oligomer. One kind of the elastomer may be used alone, or two or more kinds may be used in combination.

When the elastomer is in the form of particles, the average particle diameter of the elastomer is not particularly limited. In the eWLB (Embedded Wafer-Level Ball Grid Array) application, since it is necessary to embed semiconductor elements, when the sealing film is used for the eWLB application, the average particle diameter of the elastomer is preferably 50 μm or less. The average particle diameter of the elastomer is preferably 0.1 μm or more from the viewpoint of excellent dispersibility of the elastomer.

Commercially available products of the elastomer include acrylic elastomers such as "SG-280 EK 23", "SG-70L" and "WS-023 EK 30" manufactured by Nagase ChemteX. Further, there is also an elastomer component dispersed in a liquid resin (for example, a liquid epoxy resin) in advance among commercially available elastomer components, and an elastomer alone is not present, but may be used without problems. Examples of such commercially available products include "MX-136" and "MX-965" manufactured by KANEKA, Inc.

The amount of the elastomer added is not particularly limited from the viewpoint of imparting flexibility to the film and improving cracking, and the content of the elastomer may be 1% by mass or more, 5% by mass or more, or 10% by mass or more, based on the total amount of the thermosetting component and the elastomer. From the viewpoint of securing the fluidity required for embedding or the like, the content of the elastomer may be 30% by mass or less, 25% by mass or less, or 20% by mass or less, based on the total amount of the thermosetting component and the elastomer. From the above, the content of the elastomer may be 1 to 30% by mass, 5 to 25% by mass, or 10 to 20% by mass or less based on the total amount of the thermosetting component and the elastomer.

(other Components)

The sealing film of the present embodiment may further contain other additives. Specific examples of such additives include: pigments, dyes, mold release agents, antioxidants, surface tension modifiers, and the like.

The sealing film of the present embodiment may contain a solvent (for example, a solvent used for preparing the sealing film). The solvent may be a conventionally known organic solvent. The organic solvent may be a solvent capable of dissolving components other than the inorganic filler, and examples thereof include: aliphatic hydrocarbons, aromatic hydrocarbons, terpenes, halogens, esters, ketones, alcohols, aldehydes, and the like. One solvent may be used alone, or two or more solvents may be used in combination.

The solvent may be at least one selected from the group consisting of esters, ketones, and alcohols, from the viewpoint of reducing environmental load and from the viewpoint of easily dissolving the thermosetting component. Among them, when the solvent is a ketone, the thermosetting component is particularly easily dissolved. The solvent may be at least one selected from the group consisting of acetone, methyl ethyl ketone and methyl isobutyl ketone, from the viewpoint of less volatilization at room temperature (25 ℃) and easy removal at the time of drying.

The content of the solvent (organic solvent or the like) contained in the sealing film is preferably in the following range with respect to the total mass of the sealing film (mass including the solvent). The content of the solvent may be 0.2% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 0.6% by mass or more, or 0.7% by mass or more, from the viewpoints of easily suppressing the sealing film from becoming brittle and causing defects such as cracking of the sealing film, and easily suppressing the decrease in embedding property due to the increase in the minimum melt viscosity. The content of the solvent may be 1.5% by mass or less, or 1% by mass or less, from the viewpoints of easily suppressing a problem such as deterioration of workability due to excessively strong adhesiveness of the sealing film and easily suppressing a problem such as foaming accompanied by volatilization of the solvent (organic solvent or the like) during thermal curing of the sealing film. From these viewpoints, the content of the solvent may be 0.2 to 1.5% by mass, 0.3 to 1% by mass, 0.5 to 1% by mass, 0.6 to 1% by mass, or 0.7 to 1% by mass.

The sealing film of the present embodiment can be used for sealing a semiconductor device, embedding an electronic component disposed in a printed wiring board, and the like. In particular, the sealing film of the present embodiment is suitable for sealing a thin semiconductor device having no package substrate, such as a fan-out wafer level package and a fan-out panel level package.

The thickness (film thickness) of the sealing film may be 20 μm or more, 30 μm or more, 50 μm or more, or 100 μm or more, from the viewpoint of easily suppressing variation in-plane thickness at the time of coating and from the viewpoint of being able to improve the reliability of the sealed structure. The thickness of the sealing film may be 250 μm or less, 200 μm or less, or 150 μm or less from the viewpoint of easily obtaining a certain drying property in the depth direction at the time of coating and from the viewpoint of further reducing warpage of the sealing structure. From these viewpoints, the thickness of the sealing film may be 20 to 250 μm, 30 to 250 μm, 50 to 200 μm, or 100 to 150 μm. Further, a plurality of sealing films may be laminated to produce a sealing film having a thickness of more than 250 μm.

From the viewpoint of excellent reliability (thermal reliability) of the obtained sealed structure, the glass transition temperature of the sealing film after curing may be 80 ℃ or higher, or 100 ℃ or higher. From the viewpoint of excellent reliability (thermal reliability) of the obtained sealing structure, the glass transition temperature of the sealing film after curing may be 180 ℃ or lower, 165 ℃ or lower, or 150 ℃ or lower. From these viewpoints, the glass transition temperature of the sealing film after curing may be 80 to 180 ℃, 80 to 165 ℃, 80 to 150 ℃, or 100 to 150 ℃. The glass transition temperature of the sealing film can be adjusted by the type and content of the thermosetting component, the type and content of the elastomer component, and the like. The glass transition temperature can be measured by the method described in examples.

The sealing film of the present embodiment may be used as a sealing film with a support, for example. The sealing film 10 with a support shown in fig. 1 includes a support 1 and a sealing film 2 provided on the support 1.

As the support 1, a polymer film, a metal foil, or the like can be used. Examples of the polymer film include: polyolefin films such as polyethylene films and polypropylene films; vinyl films such as polyvinyl chloride films; polyester films such as polyethylene terephthalate films; a polycarbonate film; a cellulose acetate film; tetrafluoroethylene membranes, and the like. Examples of the metal foil include copper foil and aluminum foil.

The thickness of the support 1 is not particularly limited, and may be 2 to 200 μm from the viewpoint of excellent workability and drying property. When the thickness of the support 1 is 2 μm or more, the trouble of breaking the support at the time of coating, the trouble of bending the support due to the weight of the varnish, and the like are easily suppressed. When the thickness of the support 1 is 200 μm or less, when hot air is blown from both the coated surface and the back surface in the drying step, the problem that drying of the solvent in the varnish is hindered is easily suppressed.

In the present embodiment, the support 1 may not be used. Further, a protective layer for the purpose of protecting the sealing film may be disposed on the side of the sealing film 2 opposite to the support 1. By forming the protective layer on the sealing film 2, the workability can be improved, and troubles such as adhesion of the sealing film to the back surface of the support body during winding can be avoided.

As the protective layer, a polymer film, a metal foil, or the like can be used. Examples of the polymer film include: polyolefin films such as polyethylene films and polypropylene films; vinyl films such as polyvinyl chloride films; polyester films such as polyethylene terephthalate films; a polycarbonate film; a cellulose acetate film; tetrafluoroethylene membranes, and the like. Examples of the metal foil include copper foil and aluminum foil.

In sealing electronic components, press molding is sometimes used in which a solid or liquid resin sealing material is molded with a mold. For example, transfer molding in which a pellet (pellet) shaped resin sealing material is melted and the resin is poured into a mold to perform sealing is sometimes used. However, in transfer molding, since a molten resin is poured into the mold, an unfilled portion may be formed when sealing a large area. Therefore, in recent years, compression molding has been used in which a resin sealing material is supplied to a mold or a sealed body in advance and then the mold or the sealed body is molded. In compression molding, since the resin sealing material is directly supplied to the mold or the sealed body, there are advantages as follows: even if the seal is large in area, an unfilled portion is less likely to occur.

In the compression molding, a resin sealing material in a solid or liquid state can be used as in the transfer molding. However, when the sealed body is increased in size, the liquid resin sealing material may flow and be difficult to be uniformly supplied to the sealed body. Further, since it is necessary to uniformly supply the resin to the sealed body, a resin sealing material of fine particles or powder may be used as a solid resin sealing material instead of the conventional granular resin. However, the fine particle or powder resin sealing material is difficult to uniformly supply the resin sealing material to the mold or the sealed body, and the fine particle or powder resin sealing material is a source of dust generation, and there is a concern about contamination of the apparatus or the clean room.

In addition, in the press molding, since the resin is molded in the mold, the mold must be increased in size in order to increase the size of the sealing structure. However, since the large size of the mold requires high mold accuracy, the difficulty in the technology increases, and the manufacturing cost of the mold greatly increases.

In contrast, according to the sealing film, the resin can be uniformly supplied to the sealed body and the generation of dust can be reduced. In addition, the following embedding ability can be obtained: sealing by press molding and sealing by a molding method (such as lamination and pressing) without using a mold (such as a high-pressure mold) can be realized.

The sealing film of the present embodiment can be suitably used for sealing electronic components. In particular, the present invention can be suitably used for sealing electronic components in thin semiconductor devices having no package substrate, such as fan-out wafer level packages and fan-out panel level packages.

< method for producing sealing film >

The sealing film 2 of the present embodiment includes the following steps: a step (preparation step) of preparing a resin composition containing a resin having a reactive functional group equivalent of more than 250g/mol as a thermosetting resin and an inorganic filler; and a step (molding step) of molding the resin composition into a film shape.

In the preparation step, a varnish (varnish-like resin composition) is prepared by mixing the components (thermosetting resin, curing agent, curing accelerator, inorganic filler, solvent, and the like) of the sealing film 2 of the present embodiment. The mixing method is not particularly limited, and a mill, a mixer, and a stirring blade may be used. The solvent (such as an organic solvent) can be used for dissolving and dispersing the components of the resin composition as the material of the sealing film 2 to prepare a varnish or for preparing a varnish as an auxiliary. Most of the solvent can be removed by a drying step after coating.

In the molding step, for example, the varnish is applied to the support 1 (e.g., a film-shaped support) and then heated and dried by blowing hot air or the like. This enables the varnish to be molded into a film shape, thereby obtaining the sealing film 10 with a support provided with the sealing film 2. The coating method is not particularly limited, and coating apparatuses such as a missing-corner wheel coater, a bar coater, a kiss coater, a roll coater, a gravure coater, and a die coater can be used.

< sealing Structure >

The sealing structure of the present embodiment includes a sealed body and a cured product (sealing portion) of the sealing film of the present embodiment sealing the sealed body. The sealing structure may be an electronic component device. The electronic component device includes an electronic component as a sealed body. Examples of the electronic component include: a semiconductor element; a semiconductor wafer; an integrated circuit; a semiconductor device; filters such as SAW filters; passive components such as sensors, etc. A semiconductor element obtained by singulating a semiconductor wafer may be used. The electronic component device may be a semiconductor device or a printed wiring board including a semiconductor element or a semiconductor wafer as an electronic component. The seal structure of the present embodiment may include a plurality of sealed bodies. The plurality of sealed bodies may be of the same type or different types.

Next, a method for manufacturing a sealed structure using the sealing film of the present embodiment will be described. Here, a case where the electronic component as the sealed body is a semiconductor element will be described. Fig. 2 is a schematic cross-sectional view for explaining an embodiment of a method for manufacturing a semiconductor device as an electronic component device, which is an embodiment of a method for manufacturing a sealing structure. The manufacturing method of the present embodiment includes: a step of arranging a plurality of semiconductor elements 20 as sealed bodies (objects to be embedded) in parallel on a substrate 30 having a temporary fixing member 40 (fig. 2 (a)); a step of embedding the semiconductor element 20 in the sealing film 2 by pressing (laminating) the sealing film 2 against the semiconductor element 20 under heating after the sealing film 10 with a support is opposed to the semiconductor element 20, the sealing film 10 with a support including a support 1 and the sealing film 2 provided on the support 1 (fig. 2 (b)); and a step of curing the sealing film 2 in which the semiconductor element 20 is embedded to obtain a cured product 2a (fig. 2 (c)). In the present embodiment, the semiconductor element 20 is sealed with the sealing film 2 by the lamination method, and then the sealing film 2 is thermally cured to obtain a sealed structure (electronic component device) including the semiconductor element 20 embedded in the cured product 2 a.

The laminator used in the lamination method is not particularly limited, and examples thereof include roll type laminators, air bag type laminators, and the like. The laminator may be of a gas-bag type capable of vacuum pressurization from the viewpoint of excellent embedding properties.

Lamination is generally carried out at a temperature less than or equal to the softening point of the support. The lamination temperature is preferably around the lowest melt viscosity of the sealing film. The pressure at the time of lamination varies depending on the size, density, and the like of the sealed body to be embedded (for example, an electronic component such as a semiconductor element). The pressure during lamination may be, for example, in the range of 0.2 to 1.5MPa, or in the range of 0.3 to 1.0 MPa. The laminating time is not particularly limited, and may be 20 to 600 seconds, 30 to 300 seconds, or 40 to 120 seconds.

The curing of the sealing film may be performed, for example, under the atmosphere or under an inert gas. The curing temperature (heating temperature) is not particularly limited, and may be 80 to 280 ℃, 100 to 240 ℃, or 120 to 200 ℃. If the curing temperature is 80 ℃ or higher, the curing of the sealing film proceeds sufficiently, and the occurrence of troubles can be suppressed. When the curing temperature is 280 ℃ or lower, thermal damage to other materials tends to be suppressed. The curing time (heating time) is not particularly limited, and may be 30 to 600 minutes, 45 to 300 minutes, or 60 to 240 minutes. When the curing time is within these ranges, the curing of the sealing film proceeds sufficiently, and more favorable production efficiency can be obtained. In addition, a plurality of conditions may be combined.

In this embodiment, a semiconductor device as a sealing structure can be obtained through the following steps of insulating layer formation, wiring pattern formation, ball mounting (ball mounting), and dicing.

First, the insulating layer 50 is provided on the side of the sealing molded article 100 peeled from the substrate 30 where the semiconductor element 20 is exposed (fig. 3(a) and (b)). Next, a wiring pattern is formed on the insulating layer 50, and then, ball-bonding is performed to form the insulating layer 52, the wiring 54, and the solder ball 56.

Next, the seal-molded product is singulated by the dicing saw 60 to obtain the semiconductor device 200.

Although the preferred embodiments of the present invention have been described above, the present invention is not necessarily limited to the above embodiments, and can be modified as appropriate within the scope not departing from the gist thereof.