CN111716847A

CN111716847A - Sealing sheet

Info

Publication number: CN111716847A
Application number: CN202010194901.4A
Authority: CN
Inventors: 土生刚志; 大原康路; 清水祐作; 饭野智绘
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2019-03-19
Filing date: 2020-03-19
Publication date: 2020-09-29
Also published as: SG10202002171YA; TW202101615A; JP2020155533A; JP7343988B2

Abstract

Provided is a sealing sheet which has good embeddability and low staining properties during sealing and good heat-resistant reliability after sealing. The sealing sheet (1) is used for sealing an electronic element (51), and is provided with, in order toward the upper side: the electronic component (51) is sealed by a first layer (2) which is in contact with the electronic component (51) and a second layer (3) which is exposed to the outside, wherein the first layer (2) and the second layer (3) are each thermosetting, the upper surface of the second layer (3) is softer than the lower surface of the first layer (2) at 90 ℃, and the ratio of the thickness T2 of the second layer (3) to the thickness T1 of the first layer (2) satisfies the following formula 1.5< T2/T1< 5.

Description

Sealing sheet

Technical Field

The present invention relates to a sealing sheet, and more particularly to a sealing sheet for sealing an electronic component.

Background

Conventionally, it has been known that an electronic component package is obtained by sealing an electronic component mounted on a substrate with a sealing sheet.

As such a sealing sheet, for example, a resin sheet having an outermost layer and an innermost layer, and the outermost layer containing a thermosetting resin and an inorganic filler has been proposed (for example, see patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-103584

Disclosure of Invention

Problems to be solved by the invention

In the case of sealing the electronic components by heating and pressing the resin sheet, from the viewpoint of manufacturing efficiency, a plurality of electronic components mounted on a large-sized substrate are prepared, and the plurality of electronic components are collectively sealed with a sealing sheet and then singulated. However, the resin sheet may not smoothly enter between the adjacent electronic components, and the embeddability of the resin sheet may be reduced. In this way, an unnecessary gap (air) is generated inside the obtained electronic component package, specifically, between the substrate and the resin sheet.

On the other hand, if the fluidity of the resin sheet is improved in order to improve the embedding property, the following problems occur: the resin sheet flows greatly and wetly spreads on the substrate, and the resin sheet protrudes outward from the substrate. In this case, the periphery of the substrate (e.g., a pressing device or the like) may be contaminated with the resin sheet.

Further, the electronic component package after sealing is also required to have heat-resistant reliability such as no occurrence of cracks due to thermal cycles.

The invention provides a sealing sheet which has embedding property and low pollution property during sealing and has good heat-resistant reliability after sealing.

Means for solving the problems

The present invention [1] includes a sealing sheet for sealing an electronic component, the sealing sheet comprising, in order toward one side in a thickness direction: a1 st layer which is in contact with the electronic component when the electronic component is sealed, and a2 nd layer which is exposed to the outside, wherein the 1 st layer and the 2 nd layer each have thermosetting properties, one surface in the thickness direction of the 2 nd layer is softer than the other surface in the thickness direction of the 1 st layer at 90 ℃, and the ratio of the thickness T2 of the 2 nd layer to the thickness T1 of the 1 st layer satisfies the formula 1.5< T2/T1< 5.

The invention [2] is the sealing sheet according to [1], which satisfies the expression 0.1< D2/T2<0.2 in the ratio of the dent amount D2 in the iron ball drop test on one surface of the 2 nd layer in the thickness direction to the thickness T2 of the 2 nd layer at 90 ℃.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the sealing sheet of the present invention, one surface in the thickness direction of the 2 nd layer is softer than the other surface in the thickness direction of the 1 st layer at 90 ℃, and the ratio of the thickness T2 of the 2 nd layer to the thickness T1 of the 1 st layer satisfies the predetermined conditions, so that the embedding property and low staining property at the time of sealing and the heat-resistant reliability after sealing are good.

Drawings

In fig. 1, a in fig. 1 and B in fig. 1 show a view for explaining an embodiment of the sealing sheet of the present invention and its production, a in fig. 1 shows a cross-sectional view of the sealing sheet, and B in fig. 1 shows a view for preparing the 1 st layer and the 2 nd layer, respectively.

In fig. 2, a-B in fig. 2 show a diagram for explaining a method of measuring a dent amount in an iron ball drop test, a in fig. 2 shows a diagram for preparing a sealing sheet and an iron ball, and B in fig. 2 shows the dent amount and an enlarged view thereof.

In fig. 3, a-C in fig. 3 are diagrams of a method for sealing an electronic component using the sealing sheet shown in a in fig. 1, a in fig. 3 a is a diagram showing a preparation of an electronic component mounting substrate and a sealing sheet, respectively, a B in fig. 3 is a diagram showing a sealing of an electronic component with the sealing sheet and a thermosetting of the sealing sheet, and a C in fig. 3 is a diagram showing a plurality of electronic component packages.

Fig. 4 is a plan view showing the evaluation of the contamination property in the example.

Description of the reference numerals

1 sealing sheet

2 layer 1

3 layer 2

8 sealing sheet

50 base plate

51 electronic component

Detailed Description

In fig. 1 a-B and fig. 3C, the vertical direction of the paper is the vertical direction (thickness direction). The upper side of the paper surface is the upper side (one side in the thickness direction), and the lower side of the paper surface is the lower side (the other side in the thickness direction).

As shown in fig. 1 a and 3 a, a sealing sheet 1 according to an embodiment of the present invention is an electronic component sealing sheet for sealing an electronic component 51 with respect to an electronic member including a substrate 50 and the electronic component 51.

The sealing sheet 1 is a member for manufacturing an electronic component package 7 described later, and is not the electronic component package 7 itself, and the sealing sheet 1 does not include the electronic component 51 and the substrate 50 on which the electronic component 51 is mounted, specifically, is a member that is distributed by itself and is industrially available.

The sealing sheet 1 is not the sealing sheet 8 (fig. 3B and 3C) after sealing the electronic component 51, that is, is a sheet before sealing the electronic component 51.

As shown in a of fig. 1, the sealing sheet 1 has a substantially plate shape (film shape) extending in a direction (surface direction) orthogonal to the thickness direction.

The sealing sheet 1 includes a1 st layer 2 and a2 nd layer 3 in this order toward the upper side. That is, the sealing sheet 1 includes: a1 st layer 2, and a2 nd layer 3 disposed on the upper surface of the 1 st layer 2. The sealing sheet 1 is preferably formed of only the 1 st layer 2 and the 2 nd layer 3.

The 1 st layer 2 is a lower layer forming the lower surface (the surface on the other side in the thickness direction) of the sealing sheet 1. The 1 st layer 2 has a substantially plate shape extending in the planar direction. The 1 st layer 2 is a contact layer which is to be brought into contact with the electronic component 51 (see a in fig. 3) when the sealing sheet 1 is to seal the electronic component 51, which will be described later.

The material of the 1 st layer 2 is, for example, a1 st composition containing a1 st organic component and a1 st inorganic filler.

The 1 st organic component contains a1 st thermosetting resin and a1 st thermoplastic resin.

The 1 st thermosetting resin is a resin that is temporarily softened by heating at the time of sealing the electronic component 51, and then melted and fluidized, and is cured by further heating.

The 1 st thermosetting resin is B-stage and not C-stage (i.e., is in a state before being completely cured) in the 1 st layer 2 before the electronic component 51 is sealed.

Examples of the 1 st thermosetting resin include epoxy resins, phenol resins, melamine resins, vinyl ester resins, cyano ester resins, maleimide resins, and silicone resins. These 1 st thermosetting resins may be used singly or in combination of 2 or more. The 1 st thermosetting resin is preferably an epoxy resin or a phenol resin, and more preferably a combination of an epoxy resin and a phenol resin, from the viewpoint of heat resistance and the like.

Examples of the epoxy resin include 2-functional 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, biphenyl type epoxy resin, and the like, and polyfunctional epoxy resins having 3 or more functions such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, trishydroxyphenylmethane type epoxy resin, tetrahydroxyphenylethane type epoxy resin, dicyclopentadiene type epoxy resin, and the like. These epoxy resins may be used alone or in combination of 2 or more. The 2-functional epoxy resin is preferably used, and bisphenol F type epoxy resin is more preferably used.

The epoxy equivalent of the epoxy resin is, for example, 230 g/eq.or less, preferably 210 g/eq.or less, and is, for example, 10 g/eq.or more, preferably 50 g/eq.or more.

The softening point of the epoxy resin is, for example, 50 ℃ or higher, preferably 70 ℃ or higher, and is, for example, 110 ℃ or lower, preferably 90 ℃ or lower.

The proportion of the epoxy resin is, for example, 40 mass% or more, preferably 60 mass% or more, and is, for example, 90 mass% or less, preferably 70 mass% or less, with respect to the 1 st thermosetting resin.

Phenolic resins are resins that cure with epoxy resins. Examples of the phenol resin include a polyfunctional phenol resin having 3 or more functions such as a phenol novolac resin, a cresol novolac resin, a phenol aralkyl resin, a phenol biphenyl resin, a dicyclopentadiene type phenol resin, and a resol resin. These phenol resins may be used singly or in combination of 2 or more. Preferred examples thereof include phenol novolac resins.

The phenolic resin has a hydroxyl group equivalent of, for example, 230 g/eq.or less, preferably 210 g/eq.or less, and, for example, 10 g/eq.or more, preferably 50 g/eq.or more.

The softening point of the phenolic resin is, for example, 40 ℃ or higher, preferably 50 ℃ or higher, and is, for example, 90 ℃ or lower, preferably 70 ℃ or lower.

The proportion of the phenol resin is, for example, 10 mass% or more, preferably 30 mass% or more, and is, for example, 60 mass% or less, preferably 40 mass% or less with respect to the 1 st thermosetting resin.

The ratio of the epoxy resin to the phenol resin is adjusted so that the total amount of hydroxyl groups in the phenol resin is, for example, 0.7 equivalent to 1.5 equivalents, preferably 0.9 equivalent to 1.2 equivalents, relative to 1 equivalent of epoxy groups in the epoxy resin.

The proportion of the 1 st thermosetting resin is, for example, 10% by mass or more, preferably 20% by mass or more, and is, for example, 50% by mass or less, preferably 40% by mass or less, relative to the 1 st organic component. The proportion of the 1 st thermosetting resin is, for example, 1 mass% or more, preferably 2 mass% or more, and, for example, 10 mass% or less, preferably 5 mass% or less, relative to the 1 st composition.

The 1 st thermoplastic resin is a resin which softens when heated, but does not thermally cure.

Examples of the 1 st thermoplastic resin include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, a polybutadiene resin, a polycarbonate resin, a thermoplastic polyimide resin, a polyamide resin (6-nylon, 6-nylon, and the like), a phenoxy resin, an acrylic resin, a saturated polyester resin (PET, and the like), a polyamideimide resin, a fluororesin, a styrene-isobutylene-styrene block copolymer, and the like. Preferred examples thereof include acrylic resins.

Examples of the acrylic resin include acrylic polymers obtained by polymerizing 1 or 2 or more kinds of alkyl (meth) acrylates having a linear or branched alkyl group as a monomer component. In addition, "(meth) acrylic acid" means "acrylic acid and/or methacrylic acid".

Examples of the alkyl group include alkyl groups having 1 to 20 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, an isobutyl group, a pentyl group, an isopentyl group, a hexyl group, a heptyl group, a cyclohexyl group, a 2-ethylhexyl group, an octyl group, an isooctyl group, a nonyl group, an isononyl group, a decyl group, an isodecyl group, an undecyl group, a lauryl group, a tridecyl group, a tetradecyl group, a stearyl group, an octadecyl group, and a dodecyl group. Preferably, an alkyl group having 1 to 6 carbon atoms is used.

The acrylic polymer may be a copolymer of an alkyl (meth) acrylate and another monomer (copolymerizable monomer).

Examples of the other monomer (copolymerizable monomer) include glycidyl group-containing monomers such as glycidyl acrylate and glycidyl methacrylate, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid, acid anhydride monomers such as maleic anhydride and itaconic anhydride, hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl acrylate, hydroxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid, hydroxyl group-containing monomers such as maleic anhydride and itaconic anhydride, Examples of the monomer include sulfonic acid group-containing monomers such as styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) acrylate, and (meth) acryloyloxynaphthalenesulfonic acid, phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate, styrene monomers such as acrylonitrile, and the like. These monomers may be used alone or in combination of 2 or more. Among these, preferred is a carboxyl group-containing monomer.

The glass transition temperature (Tg) of the 1 st thermoplastic resin is, for example, 30 ℃ or lower, preferably 0 ℃ or lower, more preferably-5 ℃ or lower, and further, for example, -50 ℃ or higher. When Tg is not more than the upper limit, the sealing sheet 1 is likely to enter the gaps between the plurality of electronic components 51 during sealing, and the embeddability is further excellent.

The glass transition temperature was obtained from the maximum value of loss tangent (tan) measured by a dynamic viscoelasticity measuring apparatus (DMA, frequency 1Hz, temperature rising rate 10 ℃/min).

The weight average molecular weight of the 1 st thermoplastic resin is, for example, 10 ten thousand or more, preferably 30 ten thousand or more, and, for example, 100 ten thousand or less. The weight average molecular weight is measured by Gel Permeation Chromatography (GPC) based on a standard polystyrene conversion value.

The proportion of the 1 st thermoplastic resin is, for example, 40% by mass or more, preferably 50% by mass or more, more preferably 55% by mass or more, and is, for example, 90% by mass or less, preferably 80% by mass or less, more preferably 65% by mass or less, relative to the 1 st organic component.

The proportion of the 1 st thermoplastic resin is, for example, 1 mass% or more, preferably 5 mass% or more, and is, for example, 30 mass% or less, preferably 20 mass% or less, relative to the 1 st composition.

The 1 st organic component may contain other organic components such as a1 st silane coupling agent in addition to the 1 st thermosetting resin and the 1 st thermoplastic resin. Preferably, the 1 st organic component contains a1 st silane coupling agent. Thus, the silane coupling agent improves the affinity between the resin and the filler, and therefore, the dispersion stability is improved when the filler is highly filled.

Examples of the 1 st silane coupling agent include a vinyl-containing silane coupling agent, an epoxy-containing silane coupling agent, a styrene-containing silane coupling agent, a (meth) acrylic acid-containing silane coupling agent, an amino-containing silane coupling agent, an isocyanurate-containing silane coupling agent, a mercapto-containing silane coupling agent, and the like, and preferably include an epoxy-containing silane coupling agent.

Examples of the epoxy group-containing silane coupling agent include 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and 3-glycidoxypropyltriethoxysilane. From the viewpoint of reactivity, 3-glycidoxypropyltriethoxysilane is preferably used.

The proportion of the 1 st silane coupling agent is, for example, 1 mass% or more, preferably 5 mass% or more, and is, for example, 20 mass% or less, preferably 10 mass% or less, relative to the 1 st organic component. The proportion of the 1 st silane coupling agent is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and is, for example, 5% by mass or less, preferably 3% by mass or less, relative to the 1 st composition.

The proportion of the 1 st organic component is, for example, 5% by mass or more, preferably 10% by mass or more, and is, for example, 50% by mass or less, preferably 35% by mass or less, and more preferably 20% by mass or less, relative to the 1 st composition.

Examples of the 1 st inorganic filler include quartz glass, talc, silica (fused silica, crystalline silica, or the like), alumina, aluminum nitride, silicon nitride, boron nitride, and the like. These inorganic fillers may be used alone or in combination of 2 or more. The inorganic filler is preferably silica or alumina, and more preferably silica.

The size of the 1 st inorganic filler is not particularly limited, and specifically, the average particle diameter is, for example, 0.1 μm or more, preferably 0.2 μm or more, and is, for example, 20 μm or less, preferably 15 μm or less. In addition, 2 or more kinds of inorganic fillers having different average particle diameters may be used in combination. Such an inorganic filler is described in, for example, Japanese patent laid-open publication No. 2016-.

The proportion of the 1 st inorganic filler is, for example, 50% by mass or more, preferably 65% by mass or more, more preferably 80% by mass or more, and is, for example, 95% by mass or less, preferably 90% by mass or less, relative to the 1 st composition. When the ratio of the 1 st inorganic filler is in the above range, the heat-resistant reliability of the electronic component package 7 (described later) is further improved.

The 1 st composition may further contain a curing accelerator and a pigment.

The curing accelerator is a catalyst (heat curing catalyst) that accelerates the curing of the thermosetting resin by heating. Examples of the curing accelerator include imidazole compounds such as 2-phenyl-4, 5-dihydroxydimethylimidazole (2PHZ-PW) and 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ), and organophosphorus compounds. Preferred examples thereof include imidazole compounds. Further, there may be mentioned a clathrate compound containing the above imidazole compound as a guest and hydroxyisophthalic acid (HIPA) as a host. The clathrate is described in, for example, japanese patent application laid-open No. 2012 and 232994. These curing accelerators may be used singly or in combination of 2 or more.

The proportion of the curing accelerator is, for example, 0.1 part by mass or more and, for example, 5 parts by mass or less with respect to 100 parts by mass of the 1 st thermosetting resin.

Examples of the pigment include black pigments such as carbon black. The average particle diameter of the pigment is, for example, 0.001 to 1 μm. These pigments may be used alone or in combination of 2 or more.

The proportion of the pigment is, for example, 0.1% by mass or more and, for example, 5% by mass or less based on the composition 1.

Further, the composition 1 may contain additives other than the above components in an appropriate ratio.

The thickness T1 of the 1 st layer 2 is, for example, 10 μm or more, preferably 50 μm or more, and is, for example, 100 μm or less, preferably 80 μm or less.

The 2 nd layer 3 is an upper layer forming an upper surface (a surface on one side in the thickness direction) of the sealing sheet 1. The 2 nd layer 3 has a substantially plate shape extending in the planar direction. The 2 nd layer 3 is disposed on the entire upper surface of the 1 st layer 2. The 2 nd layer 3 is an exposed layer exposed to the outside (upper side) when the electronic component 51 is sealed with the sealing sheet 1, which will be described later. The 2 nd layer 3 is preferably a non-contact layer which is not in contact with the electronic component 51.

The material of the 2 nd layer 3 is a2 nd composition containing a2 nd organic component and a2 nd inorganic filler material.

The 2 nd organic component contains a2 nd thermosetting resin, preferably a2 nd thermosetting resin and a2 nd thermoplastic resin.

The 2 nd thermosetting resin may be a thermosetting resin similar to the thermosetting resin exemplified in the 1 st thermosetting resin. The 2 nd thermosetting resin preferably includes an epoxy resin and a phenol resin, and specifically includes a combination of an epoxy resin and a phenol resin.

The proportion of the epoxy resin is, for example, 40 mass% or more, preferably 60 mass% or more, and is, for example, 90 mass% or less, preferably 70 mass% or less, with respect to the 2 nd thermosetting resin.

The proportion of the phenol resin is, for example, 10 mass% or more, preferably 30 mass% or more, and is, for example, 60 mass% or less, preferably 40 mass% or less with respect to the 2 nd thermosetting resin.

The proportion of the 2 nd thermosetting resin is, for example, 60 mass% or more, preferably 70 mass% or more, and is, for example, 100 mass% or less, preferably 95 mass% or less, and more preferably 90 mass% or less with respect to the 2 nd organic component. The proportion of the 2 nd thermosetting resin is, for example, 5 mass% or more, preferably 10 mass% or more, and, for example, 25 mass% or less, preferably 15 mass% or less, with respect to the 2 nd composition.

Examples of the 2 nd thermoplastic resin include the same thermoplastic resins as those exemplified in the 1 st thermoplastic resin. Preferred examples thereof include acrylic resins.

The proportion of the 2 nd thermoplastic resin is, for example, 0 mass% or more, preferably 1 mass% or more, more preferably 5 mass% or more, and is, for example, 40 mass% or less, preferably 30 mass% or less, more preferably 20 mass% or less with respect to the 2 nd organic component. The proportion of the 2 nd thermoplastic resin is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and is, for example, 10% by mass or less, preferably 5% by mass or less, relative to the 2 nd composition.

The mass ratio A2 of the 2 nd thermoplastic resin to the 2 nd organic component is preferably smaller than the mass ratio A1 of the 1 st thermoplastic resin to the 1 st organic component. Specifically, the difference in mass ratio (a1-a2) is, for example, 5 mass% or more, preferably 10 mass% or more, more preferably 25 mass% or more, and is, for example, 60 mass% or less, preferably 50 mass% or less. When the difference is within the above range, the upper surface of the 2 nd layer 3 can be more surely made softer than the lower surface of the 1 st layer 2.

The 2 nd organic component may contain other organic components such as a2 nd silane coupling agent in addition to the 2 nd thermosetting resin and the 2 nd thermoplastic resin. Preferably, the 2 nd organic component contains a2 nd silane coupling agent. Thus, the silane coupling agent improves the affinity between the resin and the filler, and therefore, the dispersion stability is improved when the filler is highly filled.

Examples of the 2 nd silane coupling agent include silane coupling agents similar to those exemplified as the 1 st silane coupling agent. Preferably, an epoxy group-containing silane coupling agent is used.

The proportion of the 2 nd silane coupling agent is, for example, 1 mass% or more, preferably 5 mass% or more, and is, for example, 20 mass% or less, preferably 10 mass% or less, relative to the 2 nd organic component. The proportion of the 2 nd silane coupling agent is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and is, for example, 5% by mass or less, preferably 3% by mass or less, relative to the 2 nd composition.

The proportion of the 2 nd organic component is, for example, 5% by mass or more, preferably 10% by mass or more, and is, for example, 50% by mass or less, preferably 35% by mass or less, and more preferably 20% by mass or less, relative to the 2 nd composition.

Examples of the 2 nd inorganic filler include inorganic fillers similar to those exemplified as the 1 st inorganic filler. Preferred examples thereof include silica.

The proportion of the 2 nd inorganic filler is, for example, 50% by mass or more, preferably 65% by mass or more, more preferably 80% by mass or more, and is, for example, 95% by mass or less, preferably 90% by mass or less, relative to the 2 nd composition. When the ratio of the 2 nd inorganic filler is in the above range, the heat-resistant reliability of the electronic component package 7 (described later) is excellent.

The ratio [ C2/C1] of the ratio C2 (mass%) of the 2 nd inorganic filler to the 2 nd composition to the ratio C1 (mass%) of the 1 st inorganic filler to the 1 st composition is, for example, 0.5 or more, preferably 0.8 or more, and, for example, 2.0 or less, preferably 1.3 or less. When the ratio is within the above range, cracks at the interface between the 1 st layer 2 and the 2 nd layer 3 can be suppressed in the electronic component package 7 (described later).

The composition No. 2 may contain the curing accelerator, the pigment and the like exemplified in the composition No. 1 in an appropriate ratio.

The thickness T2 of the 2 nd layer 3 is, for example, 100 μm or more, preferably 130 μm or more, more preferably 150 μm or more, and is, for example, 1000 μm or less, preferably 500 μm or less, more preferably 300 μm or less.

The ratio of the thickness T2 of the 2 nd layer 3 to the thickness T1 of the 1 st layer 2 satisfies formula (1), preferably formula (2).

1.5<T2/T1<5 (1)

1.8≤T2/T1≤4.5 (2)

By satisfying the above formula, both low contamination during sealing and heat resistance reliability after sealing can be achieved.

In the sealing sheet 1, the upper surface of the 2 nd layer 3 is softer than the lower surface of the 1 st layer 2 at 90 ℃. That is, the lower surface (the other surface in the thickness direction) of the 1 st layer 2 is harder than the upper surface (the one surface in the thickness direction) of the 2 nd layer 3 at 90 ℃. In other words, the upper surface of the 2 nd layer 3 is more easily dented at 90 ℃ than the lower surface of the 1 st layer 2.

Specifically, as shown in the iron ball dropping test in fig. 2 a, the sealing sheet 1 is placed on the heating table 10 with the 1 st layer 2 on the upper side, the sealing sheet 1 is heated to 90 ℃, and then the iron balls 11 are dropped onto the surface (lower surface) of the 1 st layer 2. At this time, as shown in B of fig. 2, the amount of recess (depth) formed on the surface of the 1 st layer 2 is D1. Similarly, the sealing sheet 1 is placed on the heating stage 10 with the 2 nd layer 3 on the upper side, the sealing sheet 1 is heated to 90 ℃, and then the iron balls 11 are dropped onto the surface (upper surface) of the 2 nd layer 3. At this time, the amount of recess (depth) formed in the surface of the 2 nd layer 3 was D2. In this case, the amount of dishing D2 of the 2 nd layer 3 is greater than the amount of dishing D1 of the 1 st layer 2. Namely, D1< D2 is satisfied.

Specifically, the dent amount D1 in the iron ball drop test is less than 20 μm, preferably 15 μm or less, and 5 μm or more, preferably 10 μm or more, for example.

The dent amount D2 in the iron ball drop test is, for example, 20 μm or more, preferably 25 μm or more, and is, for example, 100 μm or less, preferably 40 μm or less.

For the size of the iron ball, the diameter was 18mm, the weight was 10g, and the falling height was 10 cm. In detail, the following examples are given.

When the 2 nd layer 3 is softer than the 1 st layer 2 at 90 ℃, embeddability and low contamination at the time of sealing and heat-resistant reliability after sealing can be improved.

In the sealing sheet 1, it is preferable that 0.1< D2/T2<0.2, more preferably 0.15. ltoreq. D2/T2. ltoreq.0.19 is satisfied. When the ratio is within the above range, both low contamination and embeddability can be more reliably achieved.

In the production of the sealing sheet 1, as shown in fig. 1B, the 1 st layer 2 and the 2 nd layer 3 are prepared.

For example, the 1 st composition is dissolved and/or dispersed in a solvent (for example, methyl ethyl ketone, toluene, ethyl acetate, etc.) to prepare a1 st varnish, which is applied to the 1 st release sheet 4 indicated by a virtual line and dried. Thereby, the 1 st layer 2 is prepared in a state of being supported by the 1 st release sheet 4.

The 2 nd composition is dissolved and/or dispersed in a solvent to prepare a2 nd varnish, which is applied to a2 nd release sheet 5 shown by a virtual line and dried. Thereby, the 2 nd layer 3 is prepared in a state of being supported by the 2 nd release sheet 5.

Alternatively, the layer 1, layer 2 and/or layer 2, layer 3 may be prepared by kneading extrusion without preparing a varnish.

The 1 st thermosetting resin in the 1 st layer 2 and the 2 nd thermosetting resin in the 2 nd layer 3 are, for example, B-stage thermosetting resins.

Then, the 1 st layer 2 and the 2 nd layer 3 were bonded.

Next, a method of manufacturing the electronic component package 7 by sealing the electronic component 51 using the sealing sheet 1 will be described with reference to a-C in fig. 3. The electronic component 51, the electronic component package 7, and the manufacturing method thereof are also described in japanese patent application laid-open No. 2016-.

As shown in a of fig. 3, first, an electronic component 51 is prepared.

The electronic component 51 has a substantially flat plate shape extending in the plane direction. The electronic component 51 is not particularly limited, and various electronic components can be mentioned, for example, a hollow electronic component, a semiconductor component, and the like. A plurality of electronic components 51 are mounted so as to face the upper surface of the substrate 50. The plurality of electronic components 51 are flip-chip mounted on the substrate 50, for example. In this case, electrodes (not shown) provided on the lower surfaces of the plurality of electronic components 51 are electrically connected to terminals (not shown) provided on the upper surface of the substrate 50. Further, the electronic component 51 may be die-bonded to the electronic component via an adhesive layer (die-bonding film or the like) not shown.

In order to prepare the electronic component 51, an electronic component mounting substrate 55 is prepared, and the electronic component mounting substrate 55 includes the electronic component 51 and a substrate 50 on which the electronic component 51 is mounted.

The substrate 50 is, for example, a printed circuit board. The substrate 50 has a substantially flat plate shape extending in the planar direction. The substrate 50 has a size that surrounds the plurality of electronic components 51 in a plan view. The substrate 50 has terminals (not shown) on its upper surface, which are electrically connected to the electronic components 51. The substrate 50 is made of, for example, a ceramic plate, a glass epoxy plate, or the like.

Next, the sealing sheet 1 is prepared.

The size of the sealing sheet 1 is adjusted to a size capable of collectively sealing the plurality of electronic components 51, that is, a size including all of the plurality of electronic components 51 when projected in the thickness direction.

Next, as shown in B of fig. 3, the electronic component 51 is sealed with the sealing sheet 1.

For example, the electronic component 51 is sealed with the sealing sheet 1 by using a flat press 97 having a lower plate 98 and an upper plate 99 shown by a virtual line B in fig. 3.

Electronic component mounting board 55 is disposed on lower plate 98. Specifically, the lower surface of substrate 50 is placed on the upper surface of lower plate 98.

Next, the sealing sheet 1 is disposed on the electronic component mounting substrate 55. Specifically, the 1 st layer 2 is brought into contact with the upper surfaces of the plurality of electronic components 51. On the other hand, the 2 nd layer 3 faces the upper side. At this time, in the case where the 1 st release sheet 4 supports the 1 st layer 2, the 1 st release sheet 4 is peeled from the 1 st layer 2.

Next, the upper plate 99 is pressed down toward the sealing sheet 1. At the same time, the sealing sheet 1 is heated by a heat source (not shown) provided in the lower plate 98 and the upper plate 99.

The heating temperature is, for example, 40 ℃ or higher, preferably 60 ℃ or higher, and is, for example, 100 ℃ or lower, preferably 95 ℃ or lower. The pressure is, for example, 0.05MPa or more, preferably 0.1MPa or more, and is, for example, 10MPa or less, preferably 5MPa or less. The pressing time is, for example, 0.3 minutes or more, preferably 0.5 minutes or more, and is, for example, 10 minutes or less, preferably 5 minutes or less.

In addition to the flat press 97 (virtual line in B of fig. 3), a roll press or the like may be used for hot pressing.

When the sealing sheet 1 is hot-pressed, the sealing sheet 1 is softened and the plurality of electronic components 51 are embedded. In other words, the plurality of electronic components 51 are embedded in the sealing sheet 1.

Specifically, the 1 st layer 2 covers the upper surface and the side surfaces of the electronic component 51 and the upper surface of the substrate 50 that does not overlap with the electronic component 51 when projected in the thickness direction. That is, the 1 st layer 2 is plastically deformed in accordance with the outer shape of the electronic component 51.

On the other hand, with the 2 nd layer 3, the lower surface thereof is deformed in correspondence with the deformation of the 1 st layer 2, while the upper surface of the 2 nd layer 3 is pressed by the upper plate 99, thus maintaining a flat shape.

At this time, the 2 nd layer 3 is relatively soft, and thus the 1 st layer 2 is pushed downward. Therefore, the 1 st layer 2 also flows (dips) between the plurality of electronic components 51, for example, corners formed by the side faces of the electronic components 1 and the upper surface of the substrate 50, and buries them without a gap.

On the other hand, the layer 12 is relatively hard, and therefore does not excessively wet and spread on the substrate 50, and is less likely to flow to the outer side of the substrate 50, i.e., the lower plate 98. Therefore, the layer 12 does not easily reach the lower plate 98 and the side surface or the lower surface of the substrate 50, and contamination of the surroundings can be suppressed.

Then, the sealing sheet 1 is cured by heating. Specifically, the 1 st thermosetting resin contained in the 1 st layer 2 and the 2 nd thermosetting resin contained in the 2 nd layer 3 are thermally cured (completely cured, C-staged).

After sealing and curing, the sheet for sealing the electronic component 51 is not the sealing sheet 1 but the sealing sheet 8. The sealing sheet 8 is not flat, and has a recess that opens downward corresponding to the electronic component 51.

In the sealing sheet 8, the 1 st thermosetting resin and the 2 nd thermosetting resin are C-stage.

In the case where the 2 nd release sheet 5 supports the 2 nd layer 3 before the thermosetting of the sealing sheet 1, the 2 nd release sheet 5 is peeled from the 2 nd layer 3. Alternatively, the 2 nd release sheet 5 may be peeled from the 2 nd layer 3 before the electronic component 51 is sealed with the sealing sheet 1.

The heating temperature (curing temperature) is, for example, 100 ℃ or more, preferably 120 ℃ or more, and is, for example, 200 ℃ or less, preferably 180 ℃ or less. The heating time is, for example, 10 minutes or more, preferably 30 minutes or more, and 180 minutes or less, preferably 120 minutes or less.

When the sealing sheet 1 is thermally cured, the sealing sheet 1, the electronic component 51, and the substrate 50 are taken out from the flat press 97 and put into, for example, a heating furnace or the like. The sealing sheet 1, the electronic component 51, and the substrate 50 may be thermally cured by using a heat source provided in the flat press 97 without taking out the sealing sheet 1 from the flat press 97.

If necessary, a mark is then provided (marked) on the upper surface of the 2 nd layer 3 on the plurality of electronic components 51 by laser irradiation or the like. The mark includes information (product information, lot number, and the like) related to the electronic component package 7 described below.

As shown in fig. 3C, the sealing sheet 8 between the plurality of electronic components 51 is cut by, for example, dicing, thereby singulating the electronic components 51 and the substrate 50. Thus, the electronic component package 7 including 1 sealing sheet 8, 1

electronic component

51, and 1 substrate 50 is manufactured.

Then, the electronic component package 7 is mounted on another substrate.

In the sealing sheet 1 (sheet before forming the sealing sheet 8) shown in fig. 1 a, the upper surface of the 2 nd layer 3 is softer than the lower surface of the 1 st layer 2 at 90 ℃. The ratio of the thickness T2 of the 2 nd layer 3 to the thickness T1 of the 1 st layer 2 satisfies 1.5< T2/T1< 5.

Therefore, when the sealing sheet 1 is heated to seal the electronic component 1, the 2 nd layer 3 having a sufficient thickness can press the 1 st layer 2 to the lower side. Therefore, the 1 st layer 2 also flows between the plurality of electronic components 51, for example, to the corners formed by the side surfaces of the electronic components 1 and the upper surface of the substrate 50, and embeds them without a gap. Namely, the embeddability is excellent. Therefore, generation of an unnecessary gap in the obtained electronic component package 7 can be suppressed.

In addition, the hard 1 st layer 2 is in contact with the electronic component 51 and the substrate 50 during sealing, and therefore is less likely to spread by wetting. On the other hand, since the thickness of the soft 2 nd layer 3 is in a predetermined range, the amount of the 2 nd layer 3 which is easily wet-spread decreases. Therefore, the protrusion of the sealing sheet 1 can be suppressed. Therefore, contamination of the periphery of the electronic component package 7 can be suppressed.

On the other hand, after sealing, the relatively soft 2 nd layer 3 is sufficiently present outside the electronic component package 7 as compared with the relatively hard 1 st layer 2, and therefore cracks are less likely to occur with respect to expansion and contraction due to thermal cycles, and heat-resistant reliability is excellent.

In the sealing sheet 1, when the ratio of the depression amount D2 of the 2 nd layer 3 to the thickness T2 satisfies 0.1< D2/T2<0.2, both low staining property and embeddability can be more reliably achieved.

In addition, when the ratio of the 2 nd thermoplastic resin to the 2 nd organic component is smaller than the ratio of the 1 st thermoplastic resin to the 1 st organic component, the physical properties of the sealing sheet 1 can be easily adjusted.

Examples

The present invention will be described more specifically below with reference to examples and comparative examples. The present invention is not limited to the examples and comparative examples. Specific numerical values such as the blending ratio (content ratio), the physical property value, and the parameter used in the following description may be replaced with the upper limit (numerical values defined as "lower" or "lower") or the lower limit (numerical values defined as "upper" or "lower" or "upper" or "lower") of the above-described description of the blending ratio (content ratio), the physical property value, and the parameter corresponding thereto, which are described in the above-described "embodiment".

The components used in examples and comparative examples are shown below.

YSLV-80 XY: epoxy resin (bisphenol F type epoxy resin), epoxy equivalent: 200g/eq., softening point: 80 ℃ C., manufactured by Nissie chemical Co., Ltd

LVR8210 DL: phenol resin (novolak type phenol resin), hydroxyl group equivalent: 104g/eq., softening point: 60 ℃ C., manufactured by Rongan chemical Co., Ltd

HME-2006M: acrylic resin (20% by mass methyl ethyl ketone solution of carboxyl group-containing acrylate Polymer, weight average molecular weight: about 60 ten thousand, Tg: -30 ℃ C., manufactured by Kokusan Kogyo Co., Ltd.)

SG-70L: acrylic resin (methyl ethyl ketone solution containing 12.5% by mass of carboxyl group-containing acrylate polymer, weight average molecular weight: about 80 ten thousand, Tg: -10 ℃ C., manufactured by Nagase ChemteX Corporation

KBM-403: epoxy silane coupling agent, 3-glycidoxypropyltrimethoxysilane, Shin-Etsu Silicones Co

FB-8 SM: silica, average particle diameter: 6 μm, manufactured by electrochemical Co Ltd

SC 220G-SMJ: silica, average particle diameter: 0.5 μm, ADMATECHS CO., LTD

# 20: carbon black, average particle diameter: 50nm, manufactured by Mitsubishi chemical corporation

2 PHZ-PW: curing accelerator, imidazole compound (2-phenyl-4, 5-dihydroxydimethylimidazole), product of Siguo Kabushiki Kaisha

Example 1

The components were dissolved and dispersed in methyl ethyl ketone according to the compounding recipe shown in table 1 (the numerical values in table 1 indicate the amount of solid components.) to obtain varnish 1 and varnish 2. The solid content concentration of the 1 st varnish was 70% by mass, and the solid content concentration of the 2 nd varnish was 80% by mass.

The 1 st varnish and the 2 nd varnish were applied to the surfaces of the 1 st release sheet 4 and the 2 nd release sheet 5, respectively, and then dried at 110 ℃ for 5 minutes. Thus, the 1 st layer 2 having a thickness of 50 μm and the 2 nd layer 3 having a thickness of 200 μm were prepared, respectively.

Then, the 1 st layer 2 and the 2 nd layer 3 were bonded. Thus, the sealing sheet 1 including the 1 st layer 2 (lower layer) and the 2 nd layer 3 (upper layer) was produced.

Examples 2 to 5 and comparative examples 1 to 8

A sealing sheet 1 was produced in the same manner as in example 1, according to the compounding formulations shown in tables 1 to 2 and the thicknesses shown in table 3.

(evaluation)

The following items were evaluated. The results are shown in Table 3.

< measurement of dishing amount >

Polyethylene terephthalate (38 μm in thickness) was disposed on the upper and lower surfaces of the sealing sheets (50 mm. times.50 mm) in each of the examples and comparative examples. Then, the steel ball 11 (diameter 18mm, weight 10g) was dropped from a height of 10cm onto the upper surface of the sealing sheet after 1 minute on a hot plate 10 placed at 90 ℃ with the 1 st layer on the lower side and the 2 nd layer on the upper side. After dropping, the steel ball 11 was left for 5 minutes to be removed (see A-B in FIG. 2).

The dent amount D2 on the upper surface (surface on the 2 nd layer side) of the sealing sheet was measured by a 3CCD color confocal microscope (manufactured by Lasertec Corporation, "MC-1000A") under a condition of a confocal mode at a magnification of 5 times.

Except that the 1 st layer was disposed to be the upper side and the 2 nd layer was disposed to be the lower side, the dent amount D1 on the surface on the 1 st layer side was measured in the same manner as described above.

The results are shown in Table 3.

< evaluation of Low staining Property >

A glass plate 20 of 100mm X1.1 mm in thickness was prepared. The sealing sheets 1(80 mm. times.80 mm. times.260 μm thick) of the examples and comparative examples were disposed in the center of the glass plate 20 so as to be in contact with the layer 1, and they were bonded to each other by a vacuum flat press under a pressure of 0.1MPa, 65 ℃ and for 1 minute.

Next, the lengths L of straight lines connecting the midpoints of the opposing 2 sides of the bonded sealing sheets were measured₁、L₂(refer to fig. 4). The larger value is defined as A, and the protrusion ratio X is calculated by the following equation.

X[％]＝(A[mm]/80[mm])×100

The case where X was 100% or more and 110% or less was evaluated as "o", the case where X exceeded 110% and 120% or less was evaluated as "Δ", and the case where X exceeded 120% was evaluated as "X". The results are shown in Table 3.

< evaluation of embeddability >

A plurality of silicon chips (1 mm. times.1 mm. times.200 μm thick) were arranged in a checkered pattern so that the chip spacing became 500 μm, and a sealing sheet was bonded to the silicon chips in a1 st layer by a vacuum flat press at a pressure of 0.1MPa, 65 ℃ and for 1 minute.

In this case, the case where no voids were observed between the chips was evaluated as "good", the case where voids of less than 100 μm were observed but voids of 100 μm or more were not observed was evaluated as "large", and the case where voids of 100 μm or more were observed was evaluated as "x". The results are shown in Table 3.

< evaluation of Heat resistance reliability >

As a ceramic plate, an alumina plate of 100 mm. times.100 mm. times.200 μm in thickness was prepared. The sealing sheets (diameter: 3mm) of the examples and comparative examples were disposed in the center of the ceramic plate so as to be in contact with the layer 1, and they were bonded to each other by a vacuum flat press under a pressure of 0.3MPa, 95 ℃ and 50 seconds, followed by heat curing at 150 ℃ for 1 hour. Thus, a sample was obtained.

Next, a thermal cycle test was performed on the sample (1 cycle temperature-50 ℃ C. to 125 ℃ C., 1 hour; 1000 cycles).

Then, the samples were observed with an ultrasonic microscope (SAT), and the case where no crack or peeling was observed in the sealing sheet was evaluated as o, and the case where crack or peeling was observed was evaluated as x. The results are shown in Table 3.

[ Table 1]

[ Table 2]

[ Table 3]

Claims

1. A sealing sheet for sealing an electronic component,

the sealing sheet is provided with the following components in sequence towards one side in the thickness direction: a1 st layer which is in contact with the electronic component when the electronic component is sealed, and a2 nd layer which is exposed to the outside,

the 1 st layer and the 2 nd layer each have thermosetting properties,

one surface in the thickness direction of the 2 nd layer is softer than the other surface in the thickness direction of the 1 st layer at 90 ℃,

a ratio of the thickness T2 of the 2 nd layer to the thickness T1 of the 1 st layer satisfies the following formula:

1.5<T2/T1<5。

2. the sealing sheet according to claim 1, wherein a ratio of a dent amount D2 in an iron ball drop test on one surface of the layer 2 in a thickness direction at 90 ℃ to a thickness T2 of the layer 2 satisfies the following formula:

0.1<D2/T2<0.2。