JP2020065063A - Pre-supply type underfill material, cured product of pre-supply type underfill material, electronic component device, and manufacturing method of electronic component device - Google Patents

Abstract

To provide a pre-supply type underfill material that suppresses the occurrence of voids in a cured product even when left in a medium temperature range and has excellent moisture and heat resistance of the cured product, the cured product of the pre-supply type underfill material, an electronic component device, and a manufacturing method of the electronic component device.SOLUTION: In an electronic component device 600 including an electronic component 10, a substrate 20, a wiring 15, a connection bump 30, a film-shaped underfill material 40, and a solder resist 60, a pre-supplied type underfill material includes a radical polymerizable compound which is a (meth) acrylate compound, a radical polymerization initiator, an inorganic filler, and a flexible agent, and the radical polymerizable compound is 3 mass% to 30 mass%.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pre-supply type underfill material, a cured product of the pre-supply type underfill material, an electronic component device, and a method for manufacturing an electronic component device.

  Conventionally, as a technique for sealing elements of electronic component devices such as transistors, ICs (Integrated Circuits), and LSIs (Large-scale Integration), resin-based sealing has been the mainstream in terms of productivity and cost. An epoxy resin is widely used as a resin used for sealing. This is because the epoxy resin is well balanced in various properties such as workability, moldability, electrical properties, moisture resistance, heat resistance, mechanical properties, and adhesiveness with insert products.

  In electronic component devices such as COB (Chip on Board), COG (Chip on Glass), and TCP (Tape Carrier Package) mounted on bare chips, epoxy resin compositions that are liquid at room temperature are widely used. Also, in an electronic component device (flip chip) in which a semiconductor element is directly bump-bonded on a wiring board having a substrate made of ceramic, glass / epoxy resin, glass / imide resin, polyimide film, etc., bump-bonded semiconductor element An epoxy resin composition that is liquid at room temperature is used as an underfill material that fills the gap between the wiring board and the wiring board.

  In bare chip mounting, since the circuit forming surface is not sufficiently protected, water and ionic impurities easily enter. Further, in flip-chip mounting, since the semiconductor element and the wiring board have different thermal expansion coefficients, thermal stress is likely to occur at the connection portion. Therefore, the epoxy resin composition plays an important role in protecting electronic components from temperature, humidity or mechanical external force.

  As an underfill material containing an epoxy resin as a curable component, an epoxy resin composition using an imidazole compound as a curing accelerator (see, for example, Patent Document 1), and a thermosetting resin around the imidazole compound as a curing accelerator There is reported an epoxy resin composition (see, for example, Patent Document 2) that uses at least one of fine spherical particles and amine adduct particles obtained by coating with a film according to (1) above.

As a filling method of the underfill material, after the semiconductor element and the wiring board are metal-bonded by a method such as reflow, in the gap between the semiconductor element and the wiring board, an epoxy resin which is liquid at room temperature is utilized by utilizing the capillary phenomenon. A capillary underfill method in which the composition is infiltrated is general (post-supply type underfill material).
In the capillary underfill method, if the gap between the semiconductor element and the wiring board or the gap between the bumps becomes narrow, the filling is likely to be insufficient, and voids may easily occur. As a result, there is a concern that after the semiconductor element and the wiring board are bonded together, stress is generated due to a change in volume during cooling, and the bonded portion is easily broken.

  Therefore, before joining the semiconductor element and the wiring board, a liquid or solid (film-like) underfill material is supplied onto the wiring board, and the semiconductor element having the metal bumps is thermocompression-bonded to the semiconductor element and the wiring. A pre-feeding method has been devised in which the bonding with the substrate and the curing reaction of the underfill material are performed at once (pre-feed type underfill material). The pre-supply method has the advantage of being able to cope with narrow pitches because the underfill material is hardened as it is joined and the joint is immediately protected.

Japanese Patent Publication No. 7-53794 Japanese Patent No. 3446730

When the conventional epoxy resin composition is applied as the pre-supply type underfill material, there are the following problems.
The epoxy resin composition contains an epoxy resin and at least one of a curing catalyst and a curing agent, and when heat is applied, an epoxy ring-opening reaction occurs to increase the molecular weight. Therefore, it takes some time for the epoxy resin composition to cure, and the productivity tends to decrease. In particular, in the case of the pre-supply method, the underfill material is supplied to the wiring board or electronic component heated by the hot plate in the medium temperature range of about 50 ° C to 100 ° C. Therefore, if it takes time for the epoxy resin composition to cure, voids tend to be generated due to water, volatile compounds, and the like that adhere to the wiring board, electronic components, and the like. The voids cause defects such as peeling and cracks, and may reduce reliability.

  Changing the reaction mechanism of the underfill material from the epoxy ring-opening reaction to the radical polymerization reaction is an effective means for increasing the curing speed of the underfill material and suppressing the generation of voids. However, even with an underfill material whose reaction mechanism is a radical polymerization reaction, like the epoxy resin, the radical polymerization reaction in the medium temperature region gradually progresses and the viscosity of the underfill material rises, causing entrainment voids. It may occur. Particularly, in the pre-feed system, the underfill material may be held on the hot plate for a long time depending on the form of the package (PKG). Therefore, the pre-filling type underfill material is required to have the property of suppressing the generation of voids in the cured product even if it is left in the medium temperature region.

  In addition, the produced electronic component device may be used in an environment of high humidity and high temperature. There is a demand for performance (moisture resistance) in which the cured product of the underfill material does not separate from the chip or the wiring board even in such an environment, and the cured product does not crack.

  In view of the above circumstances, the present invention suppresses the generation of voids in a cured product even when left in a medium temperature region, and has excellent moisture resistance and heat resistance of the cured product. An object is to provide an object, an electronic component device, and a method for manufacturing an electronic component device.

The present invention has been made in view of the above problems, and includes the following embodiments.
<1> A radically polymerizable compound containing a compound represented by the following general formula (I),
Radical polymerization initiator,
An inorganic filler,
A flexible agent containing a compound having a structural unit represented by the following general formula (II) or (III),
The pre-filled underfill material in which the content of the compound represented by the general formula (I) is 3% by mass to 30% by mass.

In formula (I), R ₁ and R ₂ are each independently a hydrogen atom or a methyl group, and m and n are each independently a positive number. In formulas (II) and (III), R ₃ , R ₄ , R ₇ , R ₈ and R ₉ are each independently a hydrogen atom or a methyl group, and R ₅ , R ₆ , R ₁₀ and R ₁₁ And R ₁₂ are each independently C _t H _{2t + 1} , t is an integer of 1 to 8, and p, q, x, y, and z are each independently a positive number. R ₃ and R ₄ may be the same or different. R ₇ , R ₈ and R ₉ may be the same or different. R ₅ and R ₆ are different from each other. R ₁₀ and R ₁₁ are different from each other. R ₁₁ and R ₁₂ are different from each other. R ₁₀ and R ₁₂ may be the same or different. R ₅ , R ₆ , R ₁₀ , R ₁₁ and R ₁₂ may each independently be partially modified.

<2> The pre-supply type underfill material according to <1>, wherein the sum of m and n in the general formula (I) is 3.0 to 20.0.

<3> The pre-feed according to <1> or <2>, wherein the compound having the structural unit represented by the general formula (II) or (III) has a weight average molecular weight of 10,000 to 700,000. Mold underfill material.

<4> A cured product of the pre-filled underfill material according to any one of <1> to <3>.

<5> An electronic component device having the cured product of the pre-filled underfill material according to <4>.

<6> A method of manufacturing an electronic component device, which comprises electrically connecting an electronic component and a wiring board through a joint portion to manufacture an electronic component device, the surface of the electronic component facing the wiring board. And the pre-supplied underfill material according to any one of <1> to <3> on at least one surface selected from the group consisting of the surface of the wiring board facing the electronic component. Supply process to supply,
A method of manufacturing an electronic component device, comprising a step of bonding the electronic component and the wiring board via a bonding portion and curing the pre-supply type underfill material.

<7> An electronic component, a wiring board that is disposed so as to face the electronic component, and is electrically joined to the electronic component via a joint portion, and the electronic component is disposed between the electronic component and the wiring substrate. And a cured product of the pre-supply type underfill material according to any one of <1> to <3> above.

  According to the present invention, the occurrence of voids in the cured product is suppressed even when left in the medium temperature region, and the pre-supply type underfill material excellent in moisture resistance and heat resistance of the cured product, the cured product of the pre-supply type underfill material, An electronic component device and a method of manufacturing the electronic component device are provided.

It is sectional drawing explaining the process of the manufacturing method of the electronic component apparatus which uses the pre-supply type underfill material of a liquid at room temperature. It is sectional drawing explaining the process of the manufacturing method of the electronic component apparatus which uses a film-form pre-feed type underfill material at room temperature.

  Hereinafter, modes for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and ranges thereof, and does not limit the present invention.

In the present specification, the term “process” includes not only a process independent from other processes but also the process even if the process is not clearly distinguishable from other processes as long as the purpose of the process is achieved. Be done.
In the present specification, the numerical ranges indicated by using "to" include the numerical values before and after "to" as the minimum value and the maximum value, respectively.
In the present specification, the content rate of each component in the underfill material, when there are a plurality of types of substances corresponding to each component in the underfill material, unless otherwise specified, of the plurality of types present in the underfill material. It means the total content of substances.
In the present specification, the particle size of each component in the underfill material is, when there are a plurality of types of particles corresponding to each component in the underfill material, unless otherwise specified, of the plurality of types present in the underfill material. It means the value for a mixture of particles.
In the present specification, (meth) acrylate means acrylate or methacrylate, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylic acid means acrylic acid or methacrylic acid.
In the present specification, the term "layer" refers to a case where when a region where the layer is present is observed, in addition to a case where the layer is formed over the entire region, a case where the layer is formed only in a part of the region. Is also included.
As used herein, the term "laminate" refers to stacking layers, two or more layers may be combined and two or more layers may be removable.

<Pre-supply type underfill material>
The pre-supply type underfill material (hereinafter, also simply referred to as an underfill material) of the present embodiment is a radically polymerizable compound containing a compound represented by the following general formula (I), a radical polymerization initiator, and an inorganic filler. And a flexible agent containing a compound having a structural unit represented by the following general formula (II) or (III), wherein the content of the compound represented by the general formula (I) is 3% by mass. Is about 30% by mass.

In formula (I), R ₁ and R ₂ are each independently a hydrogen atom or a methyl group. m and n are each independently a positive number. It should be noted that m and n, which are the number of structural units, show integer values for a single molecule, but show rational numbers that are average values as an aggregate of a plurality of types of molecules.

In formulas (II) and (III), R ₃ , R ₄ , R ₇ , R ₈ and R ₉ are each independently a hydrogen atom or a methyl group, and R ₅ , R ₆ , R ₁₀ and R ₁₁ And R ₁₂ are each independently C _t H _{2t + 1} , t is an integer of 1 to 8, and p, q, x, y, and z are each independently a positive number. R ₃ and R ₄ may be the same or different. R ₇ , R ₈ and R ₉ may be the same or different. R ₅ and R ₆ are different from each other. R ₁₀ and R ₁₁ are different from each other. R ₁₁ and R ₁₂ are different from each other. R ₁₀ and R ₁₂ may be the same or different. R ₅ , R ₆ , R ₁₀ , R ₁₁ and R ₁₂ may each independently be partially modified. The number of structural units, p, q, x, y and z, shows an integer value for a single molecule, but shows a rational number which is an average value as an aggregate of a plurality of types of molecules.

  The underfill material of the present embodiment has a high rate of curing reaction at high temperatures, and even if it is left in the medium temperature region (50 ° C. to 100 ° C.), generation of voids in the cured product is suppressed. That is, the start of the reaction is suppressed in the medium temperature range. The reason is presumed as follows.

  Since the reaction mechanism of the underfill material of the present embodiment is a radical polymerization reaction, the rate of the curing reaction in the high temperature region is faster than that of the underfill material whose reaction mechanism is an epoxy ring-opening reaction. Further, a group having an unsaturated double bond, unlike an epoxy group and the like, is relatively stable against heat, so that the reaction is suppressed even if left in the medium temperature region, and thus exists stably, It is considered that the generation of voids in the cured product is suppressed.

  Among the (meth) acrylate compounds, the compound represented by the general formula (I) imparts good fluidity at the time of heat, and therefore it is considered that the generation of voids is effectively suppressed.

  Further, the underfill material of the present embodiment contains, as a flexible agent, a compound having a structural unit represented by the general formula (II) or (III) (hereinafter, also referred to as “specific flexible agent”). . It is considered that the specific flexible agent has high wettability with respect to the compound represented by the general formula (I) and excellent compatibility, so that the moisture resistance and heat resistance are improved.

  The underfill material may be liquid or solid at room temperature. Examples of the underfill material that is solid at room temperature include a film-shaped underfill material. The underfill material is preferably liquid at room temperature.

As used herein, "room temperature" means 25 ° C. In the present specification, the term “liquid” means a substance that exhibits fluidity and viscosity, and has a viscosity, which is a measure of viscosity, of 0.0001 Pa · s to 1000 Pa · s at 25 ° C. In the present specification, “viscosity” refers to an underfill material kept at 25 ° C. and a shear viscosity of 5 using a rotary shear viscometer equipped with a cone plate (diameter 40 mm, cone angle 0 °). It is defined as the value measured at a temperature of 25 ° C. and a shear rate of 0.0 s ⁻¹ .
In the present specification, “solid at room temperature” means a state that does not correspond to the above definition of “liquid at room temperature” and that it is not a gas.

Whether the reaction of the liquid underfill material at room temperature has started in the medium temperature range depends on the change in viscosity before and after the temperature is raised to the medium temperature range (50 ° C to 100 ° C) (further left for a predetermined time if necessary). , A peak change (change in reaction behavior) in differential scanning calorimetry (DSC) and the like. In the case of an underfill material that is solid at room temperature, it can be confirmed by a change in hardness.
The components constituting the underfill material will be described below.

(Radical polymerizable compound)
The underfill material contains a compound represented by the following general formula (I) as a radically polymerizable compound, and the content rate of the compound represented by the general formula (I) is 3% by mass to 30% by mass. By adopting such a configuration, good fluidity at the time of heat is imparted, and generation of voids is effectively suppressed.

In formula (I), R ₁ and R ₂ are each independently a hydrogen atom or a methyl group, and m and n are each independently a positive number. It should be noted that m and n, which are the number of structural units, show integer values for a single molecule, but show rational numbers that are average values as an aggregate of a plurality of types of molecules.

In the general formula (I), m and n are preferably each independently 1 to 20, more preferably 1 to 15, and further preferably 1 to 10.
The sum of m and n in the general formula (I) is preferably 3.0 to 20.0, more preferably 3.0 to 15.0, and 3.0 to 10.0. More preferably.

  The content of the compound represented by the general formula (I) in the total mass of the underfill material is 3.0% by mass to 30% by mass, preferably 3.1% by mass to 28% by mass, The content is more preferably 3.2% by mass to 26% by mass, further preferably 3.3% by mass to 25% by mass. When the content of the compound represented by the general formula (I) is 3% by mass or more, the curability is excellent, and when it is 30% by mass or less, the generation of voids during curing is effective even if the compound is left in the medium temperature range. Can be suppressed.

  As the radically polymerizable compound, other radically polymerizable compound other than the compound represented by formula (I) may be contained. Examples of the other radically polymerizable compound include compounds having an unsaturated double bond in the molecule (excluding compounds represented by the general formula (I)).

  The content of the compound represented by the general formula (I) in the total amount of all radically polymerizable compounds is preferably 5% by mass or more, more preferably 7% by mass or more, and 9% by mass or more. More preferably,

  Examples of other radically polymerizable compounds include redox polymerizable compounds, emulsion emulsion polymerization compounds, and (meth) acrylate compounds. The other radically polymerizable compound is preferably a (meth) acrylate compound in consideration of applicability to electronic component devices, control of curing speed, and handling of the underfill material. The other radically polymerizable compounds may be used alone or in combination of two or more.

  The type of the (meth) acrylate compound as the other radically polymerizable compound is not particularly limited, and a conventionally known (meth) acrylate compound can be used. The (meth) acrylate compounds may be used alone or in combination of two or more. There is no particular limitation on the combination of (meth) acrylate compounds when two or more (meth) acrylate compounds are used in combination. At least one polyfunctional (meth) acrylate compound containing at least two (meth) acrylic groups in one molecule and at least one monofunctional (meth) acrylate compound containing one (meth) acrylic group in one molecule When used in combination with one type, the underfill material has a relatively low viscosity, so that the dispensing property tends to be improved.

  The polyfunctional (meth) acrylate compound is a compound in which the number of acrylic groups or methacrylic groups contained in one molecule is 2 or more, and is particularly a compound other than the compound represented by the general formula (I), There is no limit.

Examples of the polyfunctional (meth) acrylate compound include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, 1,4-butanediol diacrylate, and 1 , 6-hexanediol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, tricyclodecane dimethylol diacrylate, ditrimethylol propane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, tris ( β-hydroxyethyl) isocyanurate triacryle , Polycarbonate diol diacrylate, urethane acrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane dimethacrylate, trimethylolpropane trimethacrylate, 1,4-butanediol dimethacrylate, 1,6 -Hexanediol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, tricyclodecane dimethanol diacrylate, ditrimethylolpropane tetramethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hexamethacrylate, tris (β- Hydro Shiechiru) trimethacrylate isocyanurate, polycarbonate diol dimethacrylate, urethane methacrylates, and difunctional (meth) acrylate compounds represented by the following structural formula (VI).

In Structural Formula (IV), R ₂ and R ₃ each independently represent a hydrogen atom or a methyl group, and m and n are each independently a positive number. It should be noted that m and n, which are the number of structural units, show integer values for a single molecule, but show rational numbers that are average values as an aggregate of a plurality of types of molecules.

  The monofunctional (meth) acrylate compound is not particularly limited as long as it is a compound having one (meth) acrylic group contained in one molecule. Examples of the monofunctional (meth) acrylate compound include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth). Acrylate, t-butyl (meth) acrylate, amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl ( (Meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, hexadecyl (meth) acrylate, stearyl (meth) ac Rate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclo [5.2.1.02,6] decyl (meth) acrylate, 2- (tricyclo) [5.2.1. .02,6] dec-3-en-8-yloxyethyl (meth) acrylate, 2- (tricyclo) [5.2.1.02,6] dec-3-en-9-yloxyethyl (meth ) Acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, dimer diol mono (meth) acrylate, diethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, 2 -Methoxyethyl (meth) a Relate, 2-ethoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, 2-phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate , Phenoxy polyethylene glycol (meth) acrylate, 2-benzoyloxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, benzyl (meth) acrylate, 2-cyanoethyl (meth) acrylate, γ- (meth ) Acryloyloxypropyltrimethoxysilane, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, dicyclopenteni Oxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, tetrahydropyranyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) Acrylate, 1,2,2,6,6-pentamethylpiperidinyl (meth) acrylate, 2,2,6,6-tetramethylpiperidinyl (meth) acrylate, (meth) acryloyloxyethyl phosphate, (meth ) Acryloyloxyethyl phenyl acid phosphate, β- (meth) acryloyloxyethyl hydrogen phthalate, β- (meth) acryloyloxyethyl hydrogen succinate and ethylene oxide modified neopentyl glycol (meth) acrylate 2- (meth) acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl hexahydrophthalic acid, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl ( (Meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethyl-2-hydroxyethylphthalic acid, neopentyl glycol ( Examples thereof include (meth) acrylic acid benzoate.

  When at least one type of polyfunctional (meth) acrylate compound (including the compound represented by the general formula (I)) and at least one type of monofunctional (meth) acrylate compound are used as the radically polymerizable compound, the polyfunctional ( The ratio (polyfunctional: monofunctional) (mass basis) of the total amount of the (meth) acrylate compound and the total amount of the monofunctional (meth) acrylate compound is preferably 10: 1 to 1: 2, and 8: 1 to It is more preferably 1: 1 and even more preferably 5: 1 to 2: 1.

  From the viewpoint of stress relaxation and adhesive strength of the underfill material, at least one radical-polymerizable compound having a radical-polymerizable functional group equivalent (hereinafter abbreviated as “functional group equivalent”) of 100 to 1500 is included. Is preferred, and it is more preferred to include at least one radically polymerizable compound having a functional group equivalent of 110 to 1300. From the viewpoint of difficulty in curing and adhesive strength in the medium temperature range, it is more preferable to contain one or more radically polymerizable compounds having a functional group equivalent of 120 to 1000.

  Generally, as the numerical value of the functional group equivalent is larger, the crosslinked structure formed by the curing reaction becomes coarser and the stress relaxation property tends to be improved. On the other hand, the adhesiveness under heat, which has a trade-off relationship with the stress relaxation property, tends to decrease as the numerical value of the functional group equivalent increases. The same applies when the number of functional groups in one molecule is small. From the viewpoint of achieving both stress relaxation and excellent adhesiveness, the number of functional groups in one molecule of the radically polymerizable compound is preferably 1 to 3, and more preferably 2 or more. As a result, an underfill material having excellent stress relaxation and excellent adhesiveness can be obtained.

  Here, the functional group equivalent is a value obtained by dividing the theoretical molecular weight by the number of radically polymerizable functional groups, or the weight average molecular weight of one molecule measured by gel permeation chromatography (GPC) is a radically polymerizable unsaturated double bond. Defined as the number of bonds divided. If the molecule falls within the range, its skeleton is not specified. The radically polymerizable compound having a functional group equivalent within the above range is, for example, a compound having a functional group at the terminal and having a long chain main chain in the molecule, a long chain side chain or a branch in the molecule. Examples thereof include compounds having a separated bulky side chain. When a radical polymerizable compound having a functional group equivalent within the above numerical range is used, the crosslinked structure formed by the curing reaction by light or heat tends to become sparse. When a compound having a functional group at the terminal and having a long main chain in the molecule is used, the reaction point becomes longer because the functional group is at the terminal, which tends to relieve the stress. . In addition, the presence of long side chains or bulky side chains tends to create spaces around them and to create dense and sparse parts. This tends to relieve stress. Therefore, an underfill material containing a radically polymerizable compound having a functional group equivalent of 100 to 1300 tends to have excellent stress relaxation properties and further improve adhesive strength.

  In addition, in this specification, a weight average molecular weight means the weight average molecular weight when it measures by polystyrene conversion using gel permeation chromatography (For example, Shimadzu Corporation make, product name "C-R4A"). To do. The calibration curve is approximated by a cubic equation using a standard polystyrene 5 sample set (PStQuick MP-H, PStQuick B [manufactured by Tosoh Corporation, trade name]). The measurement conditions of GPC are shown below.

Device: (Pump: L-2130 type [Hitachi High-Technologies Corporation, trade name])
(Detector: L-2490 RI [Hitachi High-Technologies Corporation, trade name])
(Column oven: L-2350 [Hitachi High-Technologies Corporation, trade name])
Column: Gelpack GL-R440 + Gelpack GL-R450 + Gelpack GL-R400M (total 3) (Hitachi Chemical Co., Ltd., trade name)
Column size: 10.7 mm (inner diameter) x 300 mm
Eluent: Tetrahydrofuran Sample concentration: 10 mg / 2 mL
Injection volume: 200 μL
Flow rate: 0.05 mL / min Measuring temperature: 25 ° C

  The (meth) acrylate compound having a functional group equivalent of 250 g / eq to 1100 g / eq is preferably used in combination with a (meth) acrylate compound having a functional group equivalent of less than 250. The mass ratio (A1: A2) of the (meth) acrylate compound A1 having a functional group equivalent of 250 g / eq to 1300 g / eq and the (meth) acrylate compound A2 having a functional group equivalent of less than 250 is 10: 3 to 1: 1. 10 is preferable, 4: 1 to 1: 8 is more preferable, and 2: 1 to 1: 6 is further preferable.

(Flexible agent)
The underfill material contains a compound having a structural unit represented by the following general formula (II) or (III) as a flexible agent. The specific flexible agent is a block copolymer. When the compound having the structural unit represented by the general formula (II) or (III) is used as the flexible agent, the filleting property and the appearance of PKG tend to be excellent.

In the general formulas (II) and (III), R ₃ , R ₄ , R ₇ , R ₈ and R ₉ each independently represent a hydrogen atom or a methyl group, and R ₅ , R ₆ , R ₁₀ and R ₁₁ And R ₁₂ are each independently C _t H _{2t + 1} , and t is an integer of 1 to 8. Moreover, p, q, x, y, and z are each independently a positive number. The number of structural units p, q, x, y, and z shows an integer value for a single molecule, but shows a rational number that is an average value as an aggregate of a plurality of types of molecules.

In the general formulas (II) and (III), a plurality of R ₅ , R ₆ , R ₁₀ , R ₁₁ and R ₁₂ each independently may be partially modified. Examples of modification include acid modification.

In the general formulas (II) and (III), R ₃ and R ₄ may be the same or different. R ₇ , R ₈ and R ₉ may be the same or different. R ₅ and R ₆ are different from each other. R ₁₀ and R ₁₁ are different from each other. R ₁₁ and R ₁₂ are different from each other. R ₁₀ and R ₁₂ may be the same or different and are preferably the same.

In the general formulas (II) and (III), R ₃ is preferably a methyl group, and R ₄ is preferably a hydrogen atom.

In formulas (II) and (III), it is preferable that R ₅ , R ₁₀ and R ₁₂ each independently represent a methyl group or an ethyl group, and from the viewpoint of transparency and light resistance, a methyl group. Is more preferable.
R ₆ and R ₁₁ are preferably a propyl group or a butyl group, and more preferably a butyl group from the viewpoint of flexibility and adhesiveness.

  From the viewpoints of thermal shock resistance and stress reduction, the specific flexible agent is preferably a block copolymer of poly (meth) acrylate and butyl poly (meth) acrylate, and polymethylmethacrylate and polymethacrylate are preferred. It is preferably a block copolymer of butyl acrylate. The butyl poly (meth) acrylate may be any of poly (meth) acrylate-n-butyl, poly (meth) acrylate-t-butyl, and poly (meth) acrylate isobutyl.

The copolymerization ratio of poly (methyl methacrylate) and poly (butyl acrylate) is not particularly limited. The copolymerization ratio is preferably determined, for example, in consideration of the glass transition temperature (Tg) of the copolymer. The Tg of the copolymer is often expressed as a value obtained by multiplying the Tg when the monomer as the raw material of each constituent unit is a homopolymer by the copolymerization ratio of each constituent unit. It is preferred to determine the copolymerization ratio from the expected Tg of the copolymer.
For example, Tg of poly (methyl methacrylate) is 105 ° C., Tg of poly (n-butyl methacrylate) is 20 ° C., Tg of poly (t-butyl methacrylate) is 107 ° C., Tg of poly (isobutyl methacrylate) is Tg. Is 48 ° C. If it is a copolymer of methyl methacrylate and n-butyl methacrylate (copolymerization ratio is 40:60 (mass standard)), 105 × 0.4 + 20 × 0.6 = 54 ° C. and the Tg of the copolymer is predicted. can do.

  As the specific flexible agent, a compound having a structural unit represented by the general formula (III) is preferable from the viewpoint of heat resistance.

  Examples of the block copolymer of methyl methacrylate and butyl acrylate include Nanostrength M22, M22N, SM4032XM10, M51, D51N, M52, M52N, M53, SM5590, SM6290, M75, M75M, M85 and M85M (Arkema Ltd., (Trade name), and Clarity LA1114, LA2140, LA2250, LA2330, LA4285, LB550 and LM730H (Kuraray Co., Ltd., trade name) are commercially available and can be used.

  The specific flexible agent preferably has a weight average molecular weight of 10,000 to 700,000, more preferably 11,000 to 600,000.

  The specific flexible agent may have a particulate shape. From the viewpoint of sufficiently modifying the underfill material, the specific flexible agent is preferably fine. The volume average particle diameter when the specific flexible agent is particles is preferably in the range of 0.05 μm to 10 μm, and more preferably in the range of 0.1 μm to 5 μm. When the volume average particle diameter is 0.05 μm or more, the dispersibility in the underfill material tends to be improved. When the volume average particle diameter is 10 μm or less, the stress reduction tends to be excellent, the permeability and fluidity in the fine gap as the underfill material are improved, and the occurrence of voids and unfilling tends to be suppressed. . The volume average particle size of the specific flexible agent particles is measured by the same method as that of the inorganic filler described later.

  The specific flexible agent can be synthesized by living anionic polymerization or the like.

  As the flexible agent, in addition to the specific flexible agent, rubber particles or silicone rubber particles may be used in combination. Examples of the rubber particles and silicone rubber particles include those commonly used in organic resin compositions for electronic parts.

  Examples of the type of rubber particles include styrene-butadiene rubber (SBR), nitrile-butadiene rubber (NBR), butadiene rubber (BR), urethane rubber (UR), and general formula (II) or (III). An acrylic rubber (AR) other than the compound having the structural unit

  Examples of the silicone rubber particles include silicone rubber particles obtained by crosslinking linear polyorganosiloxanes such as polydimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane; the silicone rubber particles whose surface is coated with a silicone resin; And core-shell polymer particles including a core of solid silicone particles obtained by emulsion polymerization and the like and a shell of an organic polymer such as an acrylic resin. The silicone rubber particles are commercially available from, for example, Toray Dow Corning Silicone Co., Ltd. and Shin-Etsu Chemical Co., Ltd.

  The shape of the rubber particles and the silicone rubber particles may be amorphous or spherical, and is preferably spherical from the viewpoint of keeping the viscosity low in molding the underfill material.

  The content of the flexible agent is preferably 1% by mass to 30% by mass and more preferably 2% by mass to 20% by mass in the total mass of the underfill material. When the content of the flexible agent is 1% by mass or more, the stress reduction tends to be excellent, and when the content of the flexible agent is 30% by mass or less, the desired viscosity of the underfill material is maintained. , The moldability tends to be retained.

  The content of the specific flexible agent in the total amount of all the flexible agents is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 99% by mass or more, and substantially. It is preferable that no other flexible agent is contained.

(Radical polymerization initiator)
The underfill material contains a radical polymerization initiator. The type of radical polymerization initiator is not particularly limited, and conventionally known radical polymerization initiators can be used.

Examples of the radical polymerization initiator include organic peroxides; azobisisobutyronitrile, azobis-4-methoxy-2,4-dimethylvaleronitrile, azobiscyclohexanone-1-carbonitrile, azodibenzoyl, and other azo. A compound; and a redox catalyst obtained by combining a water-soluble catalyst such as potassium persulfate or ammonium persulfate with a peroxide or a combination of a persulfate with a reducing agent. The radical polymerization initiator may be used alone or in combination of two or more.
Above all, it is preferable that at least one organic peroxide is contained from the viewpoint of storage stability.

  Examples of the organic peroxide include ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; 1,1-di (t-butylperoxy) cyclohexane and 2,2-di (4,4-di (t- Peroxyketals such as butylperoxy) cyclohexyl) propane; p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-butylhydro Hydroperoxides such as peroxides; di (2-t-butylperoxyisopropyl) benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, t-butylcumi Ruperoxide, di Dialkyl peroxides such as t-hexyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 and di-t-butyl peroxide; dibenzoyl peroxide, di (4 -Methylbenzoyl) peroxide, etc .; diacyl peroxide; di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, etc .; and 2,5-dimethyl-2,5-di (benzoylperoxide) (Oxy) hexane, t-hexylperoxybenzoate, t-butylperoxybenzoate, t-butylperoxy 2-ethylhexanonate and the like peroxyesters.

  Among these, dialkyl peroxide having a phenyl group in the organic peroxide is preferable from the viewpoint of temperature stability in the medium temperature range, and dicumyl peroxide and di (2-t-butylperoxyisopropyl) benzene are preferable. More preferable.

  The content of the radical polymerization initiator contained in the underfill material is not particularly limited. For example, the content of the radical polymerization initiator is preferably 0.1 parts by mass to 20 parts by mass with respect to 100 parts by mass of the total radically polymerizable compound, and from the viewpoint of curability, 0.3 parts by mass to 10 parts by mass. Is more preferable. When the content of the radical polymerization initiator is 20 parts by mass or less with respect to 100 parts by mass of all radically polymerizable compounds, volatile components are less likely to be generated, and generation of voids in the cured product tends to be further suppressed. Further, when the content of the radical polymerization initiator is 0.1 part by mass or more, the curability tends to be improved.

  The 10-hour half-life temperature of the radical polymerization initiator is preferably 90 ° C to 150 ° C, more preferably 100 ° C to 140 ° C from the viewpoint of curability. If the 10-hour half-life temperature of the radical polymerization initiator is 90 ° C. or higher, the underfill material is hardened even if the substrate in which the underfill material is supplied is left in the medium temperature range (for example, on the hot plate stage). The start of the reaction tends to be suppressed. If the 10-hour half-life temperature of the radical polymerization initiator is 150 ° C. or less, the curing speed of the underfill material in the high temperature region (the temperature at which the electronic component and the wiring board are bonded together via the bonding portion) tends to increase. is there. As a result, the generation of voids tends to be further suppressed.

  The half-life temperature of the radical polymerization initiator is a value (° C) calculated by the following formula. Since the half-life temperature is described in the catalog of commercial products, it may be referred to.

  τ: half-life, C: constant, Ea: activation energy, R: gas constant, T: absolute temperature

  In the case of a 10-hour half-life, the absolute temperature at which τ (time factor) at which the concentration becomes half becomes 50% can be calculated. The concentration is measured by using the iodine titration method.

(Inorganic filler)
The underfill material contains an inorganic filler. The type of inorganic filler is not particularly limited, and the inorganic filler may be used alone or in combination of two or more. When two or more kinds of inorganic fillers are used in combination, for example, when two or more kinds of inorganic fillers having the same component but different average particle diameters are used, when two or more kinds of inorganic fillers having the same average particle diameter but different components are used, The case where two or more kinds of inorganic fillers having different average particle diameters and kinds are used can be mentioned.

  Examples of the inorganic filler include silica such as spherical silica and crystalline silica, calcium carbonate, clay, alumina, silicon nitride, silicon carbide, boron nitride, calcium silicate, potassium titanate, aluminum nitride, beryllia, zirconia, zircon, and phosphine. Stellite, steatite, spinel, mullite, titania, aluminum hydroxide, magnesium hydroxide, zinc borate and zinc molybdate. The state of the inorganic filler is not particularly limited, and examples thereof include powder, beads made by spheroidizing the powder, and glass fiber. From the viewpoint of fluidity and permeability of the underfill material into the fine gaps, spherical silica is preferable.

  The inorganic filler is preferably treated with a coupling agent from the viewpoint of the reaction suppressing effect in the medium temperature range. Examples of the coupling agent include various silane compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, and vinylsilane, titanium compounds, aluminum chelate compounds, and aluminum zirconium compounds. Among these, a coupling agent having an unsaturated double bond is preferable, a coupling agent having an acryloyloxy group or an α-substituted acryloyloxy group is more preferable, and a coupling agent having a group represented by the following general formula (V) is used. Agents are more preferred.

In formula (V), R ₄ represents a hydrogen atom, a methyl group or an ethyl group, and R ₅ represents an alkylene group having 1 to 30 carbon atoms. The alkylene group represented by R ₅ preferably has 20 or less carbon atoms, and more preferably 15 or less carbon atoms.

Examples of the alkylene group having 1 to 30 carbon atoms represented by R ₅ in the general formula (V) include an aliphatic hydrocarbon group having 1 to 30 carbon atoms and an alicyclic hydrocarbon having 3 to 30 carbon atoms. And a combination of an aliphatic hydrocarbon group and an alicyclic hydrocarbon group having a total carbon number of 30 or less. The alkylene group represented by R ₅ may be branched, may contain a double bond, and may have a substituent. When the alkylene group represented by R ₅ has a substituent, the carbon number of the alkylene group does not include the number of carbon atoms contained in the substituent. When the alkylene group represented by R ₅ is branched, the carbon number of the alkylene group includes the number of carbon atoms contained in the branch.

  Specific examples of the aliphatic hydrocarbon group having 1 to 30 carbon atoms include methylene group, ethylene group, propylene group, isopropylene group, n-butylene group, sec-butylene group, t-butylene group, pentylene. Group, hexylene group, octylene group, decylene group, and dodecylene group.

  Specific examples of the alicyclic hydrocarbon group having 3 to 30 carbon atoms include cyclopentylene group, cyclohexylene group, cycloheptylene group, cyclopentenylene group, and cyclohexenylene group.

  When the aliphatic hydrocarbon group or alicyclic hydrocarbon group has a substituent, examples of the substituent include an alkoxy group, an aryl group, an aryloxy group, a hydroxyl group, an amino group, a halogen atom, a methacryloxy group, and a mercapto group. , Imino groups, ureido groups, and isocyanate groups.

  The coupling agent having a group represented by the general formula (V) is more preferably a compound represented by the following general formula (VI).

_{R 4} and _{R 5} in the general formula (VI) are the same meanings as _{R 4} and _{R 5} in the general formula (V). R ₆ each independently represents an alkyl group having 1 to 30 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, a methyl group or an ethyl group. More preferably, it is a group.

Examples of the alkyl group having 1 to 30 carbon atoms represented by R ₆ in the general formula (VI) include an aliphatic hydrocarbon group having 1 to 30 carbon atoms and an alicyclic hydrocarbon having 3 to 30 carbon atoms. And a combination of an aliphatic hydrocarbon group and an alicyclic hydrocarbon group having a total carbon number of 30 or less. The alkyl group having 1 to 30 carbon atoms may be branched, may contain a double bond, and may have a substituent. In addition, when the alkyl group represented by R ₆ has a substituent, the carbon number of the alkyl group does not include the number of carbon atoms contained in the substituent. When the alkyl group represented by R ₆ is branched, the number of carbon atoms in the alkyl group includes the number of carbon atoms contained in the branch.

  When using an inorganic filler surface-treated with a coupling agent, the surface-treated inorganic filler may be mixed with other components (pretreatment method), and the non-surface-treated inorganic filler is coupled with the coupling agent. The surface treatment may be performed by mixing the agent and other components (separate addition method). From the viewpoint of suppressing the start of the reaction in the medium temperature range, it is preferable to use an inorganic filler which has been surface-treated in advance before being mixed with other components. When an inorganic filler which has been surface-treated in advance is used, a coupling agent may be further mixed.

  When the inorganic filler is surface-treated with the coupling agent, the amount of the coupling agent is preferably 0.05% by mass to 5% by mass, and 0.1% by mass to the inorganic filler. It is more preferably 2.5% by mass. When the amount of the coupling agent is 0.05% by mass or more with respect to the inorganic filler, the adhesiveness with the constituent members of the electronic component tends to be improved, and when the amount is 5% by mass or less, the molding is performed. Property, void property, and heat resistance in the medium temperature range tend to be improved.

  The average particle size of the inorganic filler is not particularly limited. For example, the average particle size of the inorganic filler is preferably 5 μm or less, more preferably 3 μm or less, still more preferably 1 μm or less. The average particle size of the inorganic filler is preferably 0.1 μm or more. When the average particle diameter of the inorganic filler is 5 μm or less, the permeability and fluidity of the underfill material into the fine gaps are improved, voids and unfilling are more difficult to occur, and the semiconductor element and the wiring board The inorganic filler is less likely to be caught in the connection portion, and poor connection tends to be less likely to occur.

  In the present specification, the average particle size of the inorganic filler is the particle size using the following method, the particle size is the class, the volume is the frequency, and the cumulative distribution expressed by the cumulative frequency is such that the cumulative distribution is 50%. Means As a method for measuring the particle size of particles, for example, a method for collectively measuring a large number of particles using a device such as laser diffraction, dynamic light scattering, small angle X-ray scattering, electron microscope, atomic force microscope And the like, and a method of measuring the particle size of each particle by imaging. A pretreatment for separating particles of 100 μm or more may be performed before measuring the particles using a method such as liquid phase centrifugal sedimentation, field flow fractionation, particle size exclusion chromatography, and hydrodynamic chromatography. When the measurement sample is a cured product, for example, the ash content obtained as a residue after treatment at a high temperature of 800 ° C. or higher in a muffle furnace or the like can be measured by the above method.

  The maximum particle size of the inorganic filler is not particularly limited. For example, the maximum particle size of the inorganic filler is preferably 20 μm or less, more preferably 15 μm or less, and more preferably 10 μm or less from the viewpoint of the size of the gap between the semiconductor elements in the electronic component to be pressure bonded. Is more preferable. When the maximum particle size of the inorganic filler is 20 μm or less, the permeability and fluidity of the underfill material into the fine gaps are improved, voids and unfilling are more difficult to occur, and the electronic component and the wiring board The inorganic filler is less likely to be caught in the connection portion, and poor connection tends to be less likely to occur.

  As a method for measuring the maximum particle size of the inorganic filler, for example, a method for collectively measuring a large number of particles using a device such as laser diffraction, dynamic light scattering, small-angle X-ray scattering, and electron microscope, atomic There is a method in which the particle size of each particle is measured by imaging with an interforce microscope or the like.

  The content of the inorganic filler in the underfill material is not particularly limited. For example, the total amount of the underfill material is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more. The content of the inorganic filler is preferably 70% by mass or less based on the total mass of the underfill material. When the content of the inorganic filler is 20% by mass or more, the strength of the cured product of the underfill material tends to improve, and the reliability such as temperature cycle resistance tends to improve.

  As the underfill material, other fillers other than the inorganic filler may be used. The content of the other fillers in all the fillers is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 3% by mass or less, substantially, other It is particularly preferable not to include the inorganic filler (0.1% by mass or less).

(Polymerization inhibitor)
The underfill material may contain a polymerization inhibitor. The type of polymerization inhibitor is not particularly limited, and known polymerization inhibitors can be used.

  When the underfill material contains a polymerization inhibitor, the content rate is not particularly limited. For example, the total amount of the underfill material is preferably 0.05% by mass to 1% by mass, more preferably 0.08% by mass to 0.7% by mass, and 0.1% by mass to 0.1% by mass. It is more preferably 5% by mass. If the content of the polymerization inhibitor is 0.05% by mass or more, the reaction in the medium temperature range tends to be suppressed, and if it is 1% by mass or less, the radical polymerization reaction in the medium temperature range tends not to be inhibited. It is in.

(Thixotropic agent)
When the underfill material is a liquid at room temperature, it may contain a thixotropic agent. The inclusion of the thixotropic agent in the underfill material that is liquid at room temperature tends to suppress the generation of voids. That is, when the underfill material flows onto the substrate without being able to maintain its shape, voids are likely to be trapped, but the inclusion of the thixotropic agent makes it difficult for the underfill material to flow. , Voids tend to be less likely to occur.

  The type of thixotropic agent is not particularly limited. The thixotropic agent commonly used in organic resin compositions for electronic parts can be used. Specifically, for example, a hydrogenated castor oil compound obtained by adding hydrogen to castor oil, an oxidized polyethylene compound obtained by oxidizing polyethylene to introduce a polar group, an amide wax synthesized from a vegetable oil fatty acid and an amine. Compounds, salts of long-chain polyaminoamides with acid polymers, unsaturated polycarboxylic acid polymers, finely divided silica, and crushed silica are mentioned.

  Among the thixotropic agents, from the viewpoint of handling property, moldability and reduction of generation of voids, salts of long-chain polyaminoamide and acid polymer, unsaturated polycarboxylic acid polymer, fine powder silica, and crushed silica are preferable. .

  As a salt of a long-chain polyaminoamide and an acid polymer, for example, ANTI-TERRA-U100 (Big Chemie Japan Co., Ltd., trade name) is commercially available, and as an unsaturated polycarboxylic acid polymer, for example, BYK-P105 (BIC Chemie Japan Co., Ltd., trade name) is commercially available.

  The fine powder silica as a thixotropic agent has an average primary particle diameter of preferably 5 nm to 200 nm, more preferably 5 nm to 50 nm. Moreover, you may use what processed the surface with the silicone oil or the coupling agent.

  As the fine powder silica, for example, R974 (Nippon Aerosil Co., Ltd., trade name) surface-treated with dimethylsilane having an average primary particle diameter of 12 nm, RX200 surface-treated with trimethylsilane having an average primary particle diameter of 12 nm (Japan Aerosil Co., Ltd., trade name), RY200 having an average primary particle size of 12 nm and surface-treated with dimethylsiloxane (Japan Aerosil Co., Ltd.), R202 (Nihon Aerosil Co., Ltd.) having an average primary particle size of 14 nm and surface-treated with dimethylsiloxane. Company, trade name), RA200H (Nihon Aerosil Co., Ltd., product name) having an average primary particle diameter of 12 nm and surface-treated with aminosilane, R805 (Nihon Aerosil Co., Ltd., product of average primary particle diameter 12 nm, surface-treated with alkylsilane) The average primary particle size is 12 nm. R7200 (Nippon Aerosil Co., Ltd., trade name) surface-treated with acryloyloxysilane, and YA050C-SP3 (Admatex Co., Ltd. trade name) having an average primary particle size of 50 nm and surface-treated with phenylsilane are commercially available products. It is available.

  The crushed silica as the thixotropic agent preferably has an average particle size of 10 nm or less, more preferably 7.5 nm or less, and further preferably 5.5 nm or less. From the viewpoint of dispersibility inside the resin and agglomeration of the crushed silica itself, the average particle size of the crushed silica is preferably 4.5 nm or more. You may use the thing which processed the surface of crushed silica with silicone oil or a coupling agent. As the crushed silica, for example, MC3000 (trade name of Admatechs Co., Ltd.) is available as a commercial product.

  The content of the thixotropic agent is preferably 1% by mass to 30% by mass and more preferably 2% by mass to 20% by mass in the total mass of the underfill material. When the content of the thixotropic agent is 1% by mass or more, generation of voids tends to be suppressed, and when the content of the thixotropic agent is 30% by mass or less, the desired amount of the underfill material is obtained. Viscosity is maintained and moldability tends to be maintained.

(Polymer component)
When the underfill material is solid at room temperature, it may contain a polymer component.
The type of polymer component is not particularly limited, and polymer components generally used in organic resin compositions for electronic parts can be used.

  Examples of the polymer component include phenoxy resin, polyimide resin, polyamide resin, polycarbodiimide resin, cyanate ester resin, acrylic resin, polyester resin, polyethylene resin, polyether sulfone resin, polyetherimide resin, polyvinyl acetal resin, urethane resin. And acrylic rubber. Among these, phenoxy resin, polyimide resin, acrylic rubber, cyanate ester resin and polycarbodiimide resin are preferable, and phenoxy resin, polyimide resin and acrylic rubber are more preferable, from the viewpoint of excellent heat resistance and film forming property. These polymer components may be used alone or as a mixture or copolymer of two or more. As the polymer component, a commercially available product or a synthesized product may be used.

  The polyimide resin can be obtained, for example, by subjecting a tetracarboxylic dianhydride and a diamine to a condensation reaction by a known method. More specifically, tetracarboxylic dianhydride and diamine are mixed in equimolar amounts in an organic solvent (the addition order of each component is arbitrary), and the reaction temperature is 80 ° C or lower, preferably 0 ° C to 60 ° C. The temperature is set at ℃, the addition reaction is performed to synthesize the polyamic acid, and the polyimide resin is obtained by further heat treatment. In addition, in order to suppress deterioration of various properties of the underfill material, it is preferable that the tetracarboxylic dianhydride is subjected to recrystallization purification treatment with acetic anhydride.

  The glass transition temperature (Tg) of the polymer component is preferably 100 ° C. or lower, and more preferably 85 ° C. or lower, from the viewpoint of excellent sticking property of the underfill material. When Tg is 100 ° C. or less, for example, bumps formed on electronic parts, electrodes formed on a wiring board, and irregularities of a wiring pattern are easily filled with an underfill material, and bubbles are less likely to remain and voids are generated. It tends to be hard to occur. The Tg is measured using a differential scanning calorimeter (DSC) (for example, Perkin Elmer, DSC-7 type) under the conditions of a sample amount of 10 mg, a heating rate of 10 ° C./min, and a measurement atmosphere of air. It is the value when it was done.

  From the viewpoint of good film forming property, the weight average molecular weight of the polymer component is preferably 10,000 or more, more preferably 30,000 or more, further preferably 40,000 or more, and more preferably 50,000 or more in terms of polystyrene. Is particularly preferable. When the weight average molecular weight is 10,000 or more, the film formability and heat resistance tend to be improved.

  The content of the polymer component is not particularly limited. When the polymer component is contained, the content of the polymer component is 1 part by mass to 500 parts by mass with respect to 100 parts by mass of the radically polymerizable compound, from the viewpoint of maintaining a good shape (film form, etc.) of the underfill material. The amount is preferably 5 parts by mass, more preferably 5 parts by mass to 300 parts by mass, still more preferably 10 parts by mass to 200 parts by mass. When the content of the polymer component is 1 part by mass or more, the effect of improving the film-forming property tends to be obtained, and when it is 500 parts by mass or less, the curability of the underfill material is improved and the adhesive force is increased. It tends to improve.

(Flux agent)
The underfill material may contain a fluxing agent.
The type of the flux agent is not particularly limited, and conventionally used amine hydrohalide salt or the like can be used. From the viewpoint of electrical properties, for example, a compound having a phenolic hydroxyl group and a carboxyl group such as hydroxybenzoic acid, an acid anhydride containing a carboxy group such as trimellitic acid, abietic acid, adipic acid, ascorbic acid, citric acid, 2 -Organic acids such as furancarboxylic acid and malic acid, compounds containing two or more alcoholic hydroxyl groups in one molecule, organic acid salts such as metal sulfonates and metal carbonyl salts, and quinolinol derivatives. More preferably, an organic acid or organic acid salt is used. The flux agents may be used alone or in combination of two or more.

  When the underfill material contains a flux agent, the content rate is not particularly limited. For example, the content of the flux agent is preferably 0.1% by mass to 10% by mass, and more preferably 0.5% by mass to 5% by mass in the total mass of the underfill material. When the content of the flux agent is 0.1% by mass or more, the wettability of the solder is improved and the connection resistance tends to be low. When the content of the flux agent is 10% by mass or less, voids are less likely to occur, and reliability such as migration resistance tends to improve.

(Ion trap agent)
The underfill material may contain an ion trap agent, if necessary, from the viewpoint of further improving the moisture resistance and the high temperature storage property. The type of ion trapping agent is not particularly limited, and an ion trapping agent generally used in organic resin compositions for electronic parts can be used. Specific examples include compounds represented by the following general formula (VII) or (VIII).

_{Mg 1-x Al x (OH} ) 2 (CO 3) x / 2 · mH 2 O ··· (VII)
BiO _x (OH) _y (NO ₃ ) _z ... (VIII)

In the general formula (VII), x is 0 <x ≦ 0.5, and m is a positive number.
In the general formula (VIII), x is 0.9 ≦ x ≦ 1.1, y is 0.6 ≦ y ≦ 0.8, and z is 0.2 ≦ z ≦ 0.4.

  The above ion trap agents are available as commercial products. For example, the compound of the general formula (VII) is available as DHT-4A (Kyowa Chemical Industry Co., Ltd., trade name). The compound of the general formula (VIII) is available as IXE500 (Tagosei Co., Ltd., trade name).

  Examples of ion trapping agents other than the above include hydrous oxides of elements selected from the group consisting of magnesium, aluminum, titanium, zirconium, and antimony. The ion trap agents may be used alone or in combination of two or more.

  When the underfill material contains an ion trapping agent, the content of the ion trapping agent is preferably 0.1% by mass to 5.0% by mass with respect to the total amount of the radically polymerizable compound, and 1.0% by mass. % -3.0 mass% is more preferable. The average particle size of the ion trap agent is preferably 0.1 μm to 3.0 μm, and the maximum particle size is preferably 10 μm or less.

  The average particle size and maximum particle size of the ion trap agent are measured using the same method as for the inorganic filler.

(Surfactant)
When the underfill material is liquid at room temperature, it may contain a surfactant from the viewpoint of further improving the fillet property.
The type of surfactant is not particularly limited, and surfactants generally used in organic resin compositions for electronic parts can be used. Examples of the surfactant include nonionic surfactants, and specific examples thereof include polyoxyalkylene alkyl ether surfactants such as polyoxyethylene alkyl ether, sorbitan fatty acid ester surfactants, and polyoxyethylene. Sorbitan fatty acid ester surfactant, polyoxyethylene sorbitol fatty acid ester surfactant, glycerin fatty acid ester surfactant, polyoxyethylene fatty acid ester surfactant, polyoxyethylene alkylamine surfactant, alkyl alkanolamide surfactant, poly Examples include ether-modified silicone surfactants, aralkyl-modified silicone surfactants, polyester-modified silicone surfactants, and polyacrylic surfactants. From the viewpoint of the effect of reducing the surface tension of the underfill material, polyether modified silicone surfactants and aralkyl modified silicone surfactants are preferable.

  As the surfactant, for example, BYK-307, BYK-333, BYK-377, and BYK-323 (Big Chemie Japan Co., Ltd., trade name) are commercially available.

In addition to the above-mentioned surfactant, a silicone-modified epoxy resin can be used as the surfactant. The silicone-modified epoxy resin can be obtained as a reaction product of an organosiloxane having a functional group that reacts with an epoxy group and an epoxy resin. The silicone-modified epoxy resin is preferably liquid at room temperature. Examples of the organosiloxane having a functional group that reacts with an epoxy group include, for example, dimethylsiloxane, diphenylsiloxane, and methylphenylsiloxane having at least one amino group, carboxy group, hydroxyl group, phenolic hydroxyl group, mercapto group, etc. in one molecule. Is mentioned.
These organosiloxanes include, for example, BY16-799, BY16-871, and BY16-004 (Toray Dow Corning Co., Ltd., trade name), X-22-1821, and KF-8010 (Shin-Etsu Chemical Co., Ltd., Trade name) is available as a commercial product.

  The weight average molecular weight of the organosiloxane is preferably in the range of 500 to 5000, more preferably 1000 to 3000. When the weight average molecular weight is 500 or more, the compatibility with the resin is prevented from being excessively improved, and the effect as an additive tends to be easily exhibited. When the weight average molecular weight is 5,000 or less, deterioration in compatibility with the resin is suppressed, separation and bleeding of the silicone-modified epoxy resin from the cured product are less likely to occur, and adhesiveness and appearance tend not to be impaired. .

  The epoxy resin used to obtain the silicone-modified epoxy resin is not particularly limited as long as it is compatible with the underfill material, and an epoxy resin generally used in organic resin compositions for electronic parts should be used. You can Specifically, for example, a glycidyl ether type epoxy resin obtained by the reaction of bisphenol A, bisphenol F, bisphenol AD, bisphenol S, naphthalene diol, hydrogenated bisphenol A and the like with epichlorohydrin; orthocresol novolac type epoxy resin and the like, A novolak type epoxy resin obtained by epoxidizing a novolak resin obtained by condensing or co-condensing a phenol compound and an aldehyde compound; a glycidyl ester type epoxy resin obtained by reacting a polybasic acid such as phthalic acid or dimer acid with epichlorohydrin; Glycidylamine type epoxy resin obtained by reaction of polyamines such as diaminodiphenylmethane and isocyanuric acid with epichlorohydrin; and obtained by oxidizing olefin bond with peracid such as peracetic acid That include linear aliphatic epoxy resin and alicyclic epoxy resin. These may be used alone or in combination of two or more. The epoxy resin used to obtain the silicone-modified epoxy resin is preferably liquid at room temperature.

(Other ingredients)
As the underfill material, other additives such as a dye, a coloring agent such as carbon black, and a diluent can be used as necessary.

(Physical properties)
The thixotropic index of the underfill material is preferably 1.0 or more, more preferably 1.5 or more, and further preferably 2.0 or more.

Thixotropic index of the underfill material, for underfill material that was kept at 25 ° C., (viscosity at a shear rate of 0.5 s ^-1) when measured viscosity with a rheometer / (5.0 s ^- Viscosity at a shear rate of ¹ ). The viscosity at a shear rate of 0.5 s ⁻¹ and the viscosity at a shear rate of 5.0 s ⁻¹ were measured using a rotary shear viscometer equipped with a cone plate (diameter 40 mm, cone angle 0 °). The value is measured at 25 ° C.

When the underfill material is liquid at 25 ° C., the viscosity of the underfill material at 25 ° C. is preferably 10 Pa · s to 150 Pa · s, more preferably 20 Pa · s to 130 Pa · s, and 30 Pa. -S-110 Pas is more preferable.
The viscosity in the medium temperature range of about 50 ° C. to 100 ° C. is preferably 0.1 Pa · s to 20 Pa · s, more preferably 0.5 Pa · s to 15 Pa · s, and more preferably 1 Pa · s to 10 Pa · s. More preferably, it is s.
The viscosity in the high temperature region during curing is preferably 0.1 Pa · s to 10 Pa · s, more preferably 0.3 Pa · s to 8 Pa · s, and 0.5 Pa · s to 5 Pa · s. Is more preferable.

<Manufacturing method of underfill material>
(Method for manufacturing underfill material that is liquid at room temperature)
The method for producing the underfill material that is liquid at room temperature is not particularly limited. For example, it is possible to obtain an underfill material which is liquid at room temperature by weighing predetermined components, mixing and kneading them using a ladle machine, a mixing roll, a planetary mixer, etc., and defoaming as necessary.

(Method of manufacturing solid underfill material at room temperature)
The method for producing the underfill material that is solid at room temperature is not particularly limited. For example, when the underfill material that is solid at room temperature is in the form of a film, first, the predetermined components are weighed and dissolved or dispersed by stirring, mixing, kneading, etc. to prepare a resin varnish, and a mold release treatment is performed. It can be manufactured by applying a resin varnish on the formed base film using a knife coater, a roll coater, an applicator or the like, and removing the organic solvent by heating.

  The organic solvent used for the preparation of the resin varnish preferably has the property of being able to uniformly dissolve or disperse each component. Examples include dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, diethylene glycol dimethyl ether, toluene, benzene, xylene, methyl ethyl ketone, tetrahydrofuran, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, dioxane, cyclohexanone, and ethyl acetate. To be These organic solvents can be used alone or in combination of two or more. Stirring and mixing or kneading at the time of preparing the resin varnish can be performed using, for example, a stirrer, a raker, a three-roll, a ball mill, a bead mill or a homodisper.

  The substrate film is not particularly limited as long as it has heat resistance that can withstand the heating conditions for volatilizing the organic solvent. Examples thereof include polyolefin films such as polypropylene film and polymethylpentene film, polyester films such as polyethylene terephthalate film and polyethylene naphthalate film, polyimide film and polyetherimide film. The base film may be a monolayer film or a multilayer film. In the case of a multilayer film, the respective layers may be made of different materials or the same material.

  The drying conditions for volatilizing the organic solvent from the resin varnish applied on the base film are preferably conditions under which the organic solvent is sufficiently volatilized. Specifically, for example, it can be performed at 50 ° C. to 200 ° C. for 0.1 minutes to 90 minutes.

<Cured product of pre-supply type underfill material and electronic component device>
The cured product of the above-mentioned pre-supplied underfill material can be used as a part of an electronic component device.
The electronic component device of the present embodiment includes a cured product of the above-mentioned pre-supply type underfill material. In one embodiment, an electronic component device includes an electronic component and a wiring board that is disposed so as to face the electronic component and that is electrically joined to the electronic component via a joining portion. A cured product of the mold underfill material is arranged between the electronic component and the wiring board.

  Examples of electronic component devices include lead frames, pre-wired tape carriers, rigid and flexible wiring boards, glass, silicon wafers and other supporting members (wiring boards), active elements such as semiconductor chips, transistors, diodes, and thyristors. There is an electronic component device obtained by mounting electronic components such as capacitors, resistors, resistor arrays, coils, and passive elements such as switches, and sealing necessary parts with the underfill material of the present embodiment.

  The underfill material of the present embodiment is particularly suitable as an underfill material for flip chip bonding, which requires high reliability. Therefore, a preferable aspect of the electronic component device of the present embodiment is an electronic component device in which a semiconductor element is flip-chip bonded by bump connection to a wiring formed on a rigid or flexible wiring board or a glass plate. Specific examples include flip chip BGA (Ball Grid Array), LGA (Land Grid Array), and COF (Chip On Film) electronic component devices.

  In the field of the flip chip in which the underfill material of the present embodiment is particularly suitable, a flip material using a lead-free solder such as a Sn—Ag—Cu-based bump material for a connection portion that connects a wiring board and a semiconductor element of an electronic component is used. A chip semiconductor element can be used. By using the underfill material of the present embodiment, good reliability tends to be maintained even for a flip chip that is bump-bonded by a lead-free solder, which is physically more brittle than conventional lead solder.

<Method of manufacturing electronic component device>
The method for manufacturing an electronic component device according to the present embodiment is a method for manufacturing an electronic component device by electrically bonding an electronic component and a wiring board via a bonding portion. A supply step of supplying the above-mentioned pre-supplied underfill material to at least one surface selected from the group consisting of the surface of the wiring board facing the wiring board and the surface of the wiring board facing the electronic component. And a joining step of joining the electronic component and the wiring board via a joining portion and hardening the pre-supply type underfill material.

  In the supply step of the above method, when the underfill material is a liquid at room temperature, the underfill material is supplied by coating. When the underfill material is a film at room temperature, the film-shaped underfill material is supplied by pasting. In addition, in the joining step, the joining of the electronic component and the wiring board may be performed together with the curing of the underfill material.

In one embodiment, a method for manufacturing an electronic component device includes the following steps.
(1) Supply step of supplying the underfill material of the present embodiment to at least one selected from the group consisting of the surface of the electronic component facing the wiring board and the surface of the wiring substrate facing the electronic component. (2) The gap between the electronic component and the wiring board is filled with an underfill material by causing the electronic component and the wiring board to face each other while being pressed via the metal bump of the connection portion, and Pressurizing step (3) of bringing the electronic component and the wiring board into contact with each other via the metal bump of the connection portion (3) The electronic component and the wiring board are separated from each other during at least one of the pressing step and the pressing step. The electronic component and the wiring board are bonded to each other via the metal bumps of the connection part by heat treatment while being pressed and contacted via the metal bumps of the connection part, and Bonding step of curing the sealing material (heat treatment step)

  Hereinafter, a method of manufacturing the electronic component device by the pre-supply method will be described with reference to the drawings. However, the present invention is not limited to the drawings. Further, the sizes of the members in each drawing are conceptual, and the relative relationship of the sizes between the members is not limited to this.

  FIG. 1 is a cross-sectional view schematically showing steps of a method of manufacturing an electronic component device by a pre-supply method using an underfill material that is liquid at room temperature. In the method of manufacturing the electronic component device of FIG. 1, an aspect in which an underfill material is applied to the surface of the wiring board facing the electronic component will be described. Further, the metal bump is provided on the electronic component side, and the electronic component and the wiring board are bonded via the metal bump. However, the present invention is not limited to these aspects.

  In FIG. 1, 1 is a semiconductor chip (electronic component), 2 is a solder bump, 3 is a connection pad, 4 is a solder resist, 5 is a wiring board, and 6 is an underfill material.

  First, in FIG. 1A, an underfill material 6 is applied to the surface of the wiring board 5 on which the connection pads 3 are provided (the side of the wiring board 5 facing the semiconductor chip 1) (supply step). Examples of the method of applying the underfill material 6 include a dispensing method, a casting method, and a printing method. The underfill material 6 may be applied to the entire area of the wiring board 5 where the connection pads 3 are provided, or may be applied to a part of the area of the wiring board 5 where the connection pads 3 are provided. By applying the underfill material 6 to a part of the area of the wiring board 5 where the connection pads 3 are provided, the underfill material 6 flows when the wiring board 5 and the semiconductor chip 1 are brought into contact with each other via the solder bumps 2. Since it is filled between the wiring board 5 and the semiconductor chip 1, it is preferable. As a pattern of applying the underfill material 6 to the wiring board 5, a cross shape or a double cross shape along the diagonal of the region of the wiring board 5 where the semiconductor chip 1 is arranged is preferable.

  Next, in FIG. 1B, the semiconductor chip 1 and the wiring substrate 5 are opposed to each other while being pressed via the solder bumps 2 to fill the gap between the semiconductor chip 1 and the wiring substrate 5 with the underfill material 6. Moreover, the semiconductor chip 1 and the connection pads 3 of the wiring board 5 are brought into contact with each other via the solder bumps 2 (pressurizing step).

  As a pressurizing condition when filling the underfill material 6 in the gap between the semiconductor chip 1 and the wiring substrate 5, the weight per bump is preferably 0.001N to 100N, and 0.005N to 50N. Is more preferable, and 0.01N to 10N is even more preferable.

  Further, as a pressurizing condition when the semiconductor chip 1 and the connection pad 3 of the wiring board 5 are brought into contact with each other via the solder bump 2, it is preferable that the weight per bump is 0.002N to 200N, It is more preferably 0.01 N to 100 N, further preferably 0.02 N to 20 N. Under this pressurizing condition, the semiconductor chip 1 and the connection pad 3 of the wiring board 5 may be joined via the solder bump 2 in a heat treatment step described later.

  During at least one of the pressurizing step and the pressurizing step, the semiconductor chip 1 and the connection pads 3 of the wiring substrate 5 are heat-treated in a state of being pressed and contacted via the solder bumps 2 and the semiconductor chip 1 and the wiring. The connection pad 3 of the substrate 5 is joined via the solder bump 2 and the underfill material 6 is cured (heat treatment step).

  The heating condition is preferably 150 ° C to 350 ° C, more preferably 220 ° C to 300 ° C, and further preferably 240 ° C to 270 ° C. This heat treatment cures the underfill material 6.

  Further, if necessary, in order to sufficiently cure the underfill material 6, heat treatment may be performed at a temperature of 120 ° C. to 200 ° C. for 0.5 hours to 6 hours.

  Through the above steps, the electronic component device of the present embodiment is manufactured.

  FIG. 2 is a cross-sectional view schematically showing steps of a method of manufacturing an electronic component device by a pre-supply method that uses a film-like underfill material that is solid at room temperature.

  First, as shown in FIG. 2A, a solder resist 60 having an opening at a position where the connection bump 30 is formed is formed on the substrate 20 having the wiring 15. Further, the connection bump 30 is formed in the opening of the solder resist 60. The solder resist 60 is not necessarily provided, but by providing the solder resist on the substrate 20, it is possible to suppress the generation of bridges between the wirings 15 and improve the connection reliability and the insulation reliability. The solder resist 60 can be formed using, for example, a commercially available solder resist ink for a package. Specific examples of the commercially available solder resist ink for packaging include SR series (trade name, manufactured by Hitachi Chemical Co., Ltd.) and PSR4000-AUS series (trade name, manufactured by Taiyo Ink Manufacturing Co., Ltd.).

  Next, as shown in FIG. 2B, a film-shaped underfill material (hereinafter, sometimes referred to as “film-shaped underfill material”) is formed on the substrate 20 on which the connection bumps 30 and the solder resist 60 are formed. Stick 40. The film-shaped underfill material 40 can be attached by, for example, hot pressing, roll laminating, or vacuum laminating. The supply area and the thickness of the film-shaped underfill material 40 are appropriately set depending on the sizes of the semiconductor chip (electronic component) 10 and the substrate 20, and the height of the connection bump 30.

  After the film-shaped underfill material 40 is attached to the substrate 20, the semiconductor chip 10 is arranged so that the wiring 15 faces the substrate 20. At this time, the wiring 15 of the semiconductor chip 10 and the connection bump 30 are aligned with each other by using a connection device such as a flip chip bonder. Subsequently, the semiconductor chip 10 and the substrate 20 are pressure-bonded while being heated at a temperature equal to or higher than the melting point of the connection bump 30, and the semiconductor chip 10 and the substrate 20 are connected via the bump 30 as shown in FIG. To do. At this time, the gap between the semiconductor chip 10 and the substrate 20 is filled with the film-like underfill material 40. As described above, the electronic component device 600 is obtained.

  In the method of manufacturing the electronic component device according to the present embodiment, the alignment bumps are temporarily fixed (with the electronic component adhesive interposed), and heat-treated in a reflow furnace to melt the connection bumps 30 to thereby melt the semiconductor chip. You may connect 10 and the board | substrate 20. At the stage of temporary fixing, it is not always necessary to form a metal joint, so that the pressure bonding can be performed under a low load, in a short time, and at a low temperature as compared with the above-mentioned method of pressure bonding with heating. Therefore, productivity tends to be improved, and deterioration of the connection portion tends to be suppressed.

  Further, after connecting the semiconductor chip 10 and the substrate 20, heat treatment may be performed in an oven or the like to further improve the connection reliability and the insulation reliability. The heat treatment is preferably performed at a temperature at which the underfill material is cured, and more preferably at a temperature at which it is completely cured. The temperature and time of the heat treatment can be set appropriately, and suitable conditions are the same as those for the underfill material that is liquid at room temperature.

  Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples.

(Preparation of underfill material)
The following components were blended in the amounts shown in Tables 1 to 3 (unit: parts by mass), kneaded and dispersed by a three-roll mill and a raker machine, and then degassed in vacuum to obtain an undercoat of Examples and Comparative Examples. A fill material was produced. In the table, "-" means that the corresponding component is not contained. The produced underfill materials were all liquids at 25 ° C.

<Radical polymerizable compound>
Radical polymerizable compound 1: A-DCP (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name, tricyclodecane dimethanol diacrylate, functional group equivalent: 152 g / eq)
Radical polymerizable compound 2: ABE-300 (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name, ethoxylated bisphenol A diacrylate, functional group equivalent: 233 g / eq, m + n≈3 in the general formula (I) (catalog value) )
-Radical polymerizable compound 3: FA-321A (trade name, manufactured by Hitachi Chemical Co., Ltd., ethoxylated bisphenol A diacrylate, functional group equivalent: 389 g / eq, m + n≈10 (catalog value) in general formula (I))
-Radical polymerizable compound 4: UA-13 (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name, urethane acrylate, functional group equivalent: 744 g / eq)
Radical polymerizable compound 5: HOA-MPE (N) (manufactured by Kyoeisha Chemical Co., Ltd., trade name, 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid, functional group equivalent: 292 g / eq)

<Flexible agent>
-Flexible agent 1: Nanostrength D51N (trade name, manufactured by Arkema Ltd., modified poly (methyl methacrylate) -poly (butyl acrylate) block copolymer, weight average molecular weight: 57,000)
-Flexible agent 2: Nanostrength M52N (manufactured by Arkema, trade name, modified poly (methyl methacrylate) -butyl polyacrylate / modified poly (methyl methacrylate) block copolymer, weight average molecular weight: 183000)
-Flexible agent 3: Clarity LA2140e (Kuraray Co., Ltd., trade name, poly (methyl methacrylate) -poly (butyl acrylate) -modified poly (methyl methacrylate) block copolymer, weight average molecular weight: 120,000)
-Flexible agent 4: Clarity LA2250 (manufactured by Kuraray Co., Ltd., trade name, polymethyl methacrylate-polybutyl acrylate-modified polymethyl methacrylate block copolymer, weight average molecular weight: 163000)
-Flexible agent 5: RICON130MA8 (Clay Valley Co., Ltd., trade name, maleic acid-modified liquid polybutadiene)
-Flexible agent 6: YS resin TO-85 (Yasuhara Chemical Co., Ltd., trade name, aromatic modified terpene polymer)
-Flexible agent 7: Knit resin Chroman L-5 (manufactured by Nikki Chemical Co., Ltd., trade name, coumarone-indene-styrene copolymer)

<Additives>
-Radical polymerization initiator: Perkadox BC-FF (trade name, dicumyl peroxide, manufactured by Kayaku Akzo Co., Ltd.)
-Polymerization inhibitor: SUMIRIZER GM (Sumitomo Chemical Co., Ltd., trade name, 2-t-butyl-6- (3-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenylacrylate)
Flux agent: adipic acid (manufactured by Asahi Kasei Chemicals Corporation)
Coupling agent: OFS-6030 (trade name, 3-methacryloyloxypropyltrimethoxysilane, manufactured by Toray Dow Corning Co., Ltd.)
Thixotropic agent: R805 (manufactured by Nippon Aerosil Co., Ltd., trade name, powder silica having a volume average particle diameter of 12 nm)

Inorganic filler: SE-2050-SMJ (manufactured by Admatechs Co., Ltd., trade name, volume average particle diameter 0.5 μm, maximum particle diameter 5 μm, methacrylate silane coupling treatment (silane coupling having 3-methacryloyloxypropyl group) Spherical silica treated with an agent)

(Evaluation)
Electronic component devices were manufactured using the underfill materials manufactured in Examples and Comparative Examples, and evaluated by the following tests. The evaluation results are shown in Tables 4 to 6.

<Void>
Using a dispenser (needle diameter: 0.3 mm), the underfill material was applied in a cross shape on the chip mounting part of the wiring board, and another cross shape was applied at a 45 ° offset so that they overlap (the total amount applied). : About 3 mg). Then, the wiring board coated with the underfill material was placed on the stage of a hot plate heated to 70 ° C. and left for 5 minutes, 30 minutes, or 60 minutes. After that, the chip is mounted on the wiring board, and thermocompression bonding is performed under the conditions of load: 7.5N, contact temperature: 150 ° C, temperature / time: 260 ° C / 5 seconds, and then at 175 ° C, 1 hour. A semiconductor device was obtained by curing.

The wiring board used for manufacturing the electronic component device has a size of 14 mm in length, 14 mm in width, and 0.30 mm in thickness, the core layer is E-679FG (Hitachi Chemical Co., Ltd., trade name), and the solder resist is AUS-308 ( The product was manufactured by Taiyo Holdings Co., Ltd., and the substrate plating was laminated in the order of Ni (5.0 μm), Pd (0.30 μm), and Au (0.35 μm).
The chip used for manufacturing the electronic component device has a size of 7.3 mm in length, 7.3 mm in width, and 0.15 mm in thickness, and bumps are copper (height 30 μm) and solder (material: SnAg, height: 15 μm). The bump pitch was 80 μm and the number of bumps was 328.

  The produced electronic component device was observed using an ultrasonic flaw detector (AT-5500, manufactured by Hitachi Construction Machinery Co., Ltd.), and the void occupancy rate was evaluated according to the following criteria.

A: Void area is 1% or less of the total area B: Void area is 1% or more and 5% or less of the total area C: Void area is 5% or more and 20% or less of the total area D: Void area is 20% or less of the total area Exceeds%

<Heat resistance after moisture absorption>
The electronic component device manufactured by the above method is heated and dried at 120 ° C. for 12 hours, and then left under the condition of 30 ° C./70% RH for 192 hours, and then the far-infrared heating type reflow furnace (preheating at 150 ° C. to 180 ° C. 50 seconds, peak temperature of 260 ° C., heating time of 250 ° C. or higher 40 seconds).
After that, using an ultrasonic flaw detector (AT-5500, manufactured by Hitachi Construction Machinery Co., Ltd., product name), the cured product of the underfill material is separated from the chip and the wiring substrate, and the presence or absence of cracks in the cured product is a defective package. Confirmed as a number. The moisture absorption heat resistance was evaluated by (number of defective packages) / (number of evaluated packages).

  As is clear from the evaluation results, the electronic component device of the example manufactured using the underfill material of the present embodiment has a small void occupancy rate even when the standing time on the stage of the hot plate is long, and moisture absorption The result of the heat resistance test was also good. Therefore, it can be seen that the underfill material using the specific flexible agent is excellent in workability, voidlessness, and heat resistance after moisture absorption.

  On the other hand, the electronic component device of the comparative example manufactured by using an underfill material containing a flexible agent that does not correspond to a specific flexible agent has a good void occupancy rate when the time left on the stage of the hot plate is short. Although it is small, the void occupancy rate increased as the standing time increased.

  In the examples, the underfill material that is liquid at room temperature is used, but the same effect can be obtained when the underfill material that is solid at room temperature is used.

1 Semiconductor chip (electronic component)
2 Solder bump 3 Connection pad 4 Solder resist 5 Wiring board 6 Encapsulation material 10 Semiconductor chip (electronic component)
15 wiring 20 substrate 30 connection bump 40 film-like underfill material 60 solder resist 600 electronic component device

Claims (7)

A radically polymerizable compound containing a compound represented by the following general formula (I),
Radical polymerization initiator,
An inorganic filler,
A flexible agent containing a compound having a structural unit represented by the following general formula (II) or (III),
The pre-filled underfill material in which the content of the compound represented by the general formula (I) is 3% by mass to 30% by mass.






[In the general formula (I), R ₁ and R ₂ are each independently a hydrogen atom or a methyl group, and m and n are each independently a positive number. In formulas (II) and (III), R ₃ , R ₄ , R ₇ , R ₈ and R ₉ are each independently a hydrogen atom or a methyl group, and R ₅ , R ₆ , R ₁₀ and R ₁₁ And R ₁₂ are each independently C _t H _{2t + 1} , t is an integer of 1 to 8, and p, q, x, y, and z are each independently a positive number. R ₃ and R ₄ may be the same or different. R ₇ , R ₈ and R ₉ may be the same or different. R ₅ and R ₆ are different from each other. R ₁₀ and R ₁₁ are different from each other. R ₁₁ and R ₁₂ are different from each other. R ₁₀ and R ₁₂ may be the same or different. R ₅ , R ₆ , R ₁₀ , R ₁₁ and R ₁₂ may each independently be partially modified. ]   The pre-filled underfill material according to claim 1, wherein the sum of m and n in the general formula (I) is 3.0 to 20.0.   The pre-supply type underfill material according to claim 1 or 2, wherein the compound having a structural unit represented by the general formula (II) or (III) has a weight average molecular weight of 10,000 to 700,000. .   A cured product of the pre-filled underfill material according to any one of claims 1 to 3.   An electronic component device comprising the cured product of the pre-filled type underfill material according to claim 4. It is a manufacturing method of an electronic component device for manufacturing an electronic component device by electrically bonding an electronic component and a wiring substrate via a bonding portion, the surface of the electronic component facing the wiring substrate and the wiring. A supply step of supplying the pre-supply type underfill material according to any one of claims 1 to 3 to at least one surface selected from the group consisting of the surface of the substrate facing the electronic component. When,
A method of manufacturing an electronic component device, comprising a step of bonding the electronic component and the wiring board via a bonding portion and curing the pre-supply type underfill material.   An electronic component, a wiring board that is disposed so as to face the electronic component, and is electrically bonded to the electronic component via a bonding portion, and the electronic component is disposed between the electronic component and the wiring board. An electronic component device comprising the cured product of the pre-filled underfill material according to any one of claims 1 to 3.