JP2016135888A - Liquid epoxy resin composition and electronic component device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid epoxy resin composition excellent in impregnation property to narrow gaps and less in generation of deposition and void of a filler, and an electronic component device having high moldability and high credibility, by flip chip mounting so that a circuit forming face of an element such as a semiconductor is opposed to a circuit forming face of a substrate via a bump and filling the resin composition to gaps between the element and the substrate.SOLUTION: A non-solvent type liquid epoxy resin composition containing (A) an epoxy resin, (B) a curing agent and (C) an inorganic filler and if needed (D) a curing accelerator and having viscosity ratio measured at rotation frequency nand nwith a rotational viscometer (n/n<0.5), η/η, i.e. thixotropic index of small than 0.8 is used.SELECTED DRAWING: None

Description

  The present invention relates to a liquid epoxy resin composition that is excellent in impregnation into a narrow gap and has little sedimentation and void generation of a filler, and an electronic component device using this resin composition.

  A semiconductor needs a package in order to protect the element from the external environment and ensure various reliability, and at the same time facilitate mounting on a substrate. There are various types of packages, but in general, an element is fixed to a tab formed on a metal lead frame, and an electrode on the element surface and an inner lead are electrically connected by a gold wire, and the element, gold A package in which a part of a wire and a lead frame is sealed by a low-pressure transfer molding method using an epoxy resin composition is widely used. Such a resin-encapsulated semiconductor device has a considerably larger package outer shape than the element size, and is extremely inefficient from the viewpoint of high-density mounting. For this reason, the package form has shifted from the pin insertion type to the surface mount type, and has been actively reduced in size and thickness. However, as long as a structure in which an element is mounted on a metal lead frame and a wire-bonded structure is sealed with resin is employed, there is a limit to increasing the mounting efficiency. Therefore, in the fields of COB (Chip on Board), hybrid ICs, modules, cards, etc., so-called flip chip mounting has been adopted in which a bare chip is mounted face-down on a substrate via bumps in order to mount some elements at high density. It was. Recently, various small packages called CSP (Chip Size / Scale Package) have been developed to cope with high integration, high functionality, high pin count, systemization, high speed, and low cost of devices. As a method for mounting an element on a substrate, flip chip mounting which is excellent in mounting efficiency, electrical characteristics, and high pin count is increasing. Also, many recent surface mount packages and CSPs have terminals arranged in an area array, and the mounting form of this type of package is the same as flip chip mounting.

  By the way, when flip chip mounting is performed, the thermal expansion coefficient is different between the element and the substrate or the CSP, so that thermal stress is generated at the joint and it is important to ensure connection reliability. In addition, since the circuit forming surface of the bare chip is not sufficiently protected, moisture and ionic impurities are liable to enter, and ensuring moisture resistance reliability is also an important issue. As a countermeasure, an epoxy resin composition as an underfill material is usually filled in the gap between the element and the substrate to interpose the reinforcing portion and protect the element. There are various methods for interposing a resin composition. Generally, there is a method of dripping a liquid epoxy resin composition around the element and soaking it in the gap between the element and the substrate by capillary action (impregnation). It is adopted (see Patent Document 1).

JP 2002-118127 A

When the epoxy resin composition used as the underfill material is impregnated in the gap between the element and the substrate using the capillary phenomenon, the impregnation time needs to be as short as possible from the viewpoint of productivity. The impregnation rate (t) in this case is expressed by the following equation (1).
t = 3ηL ² / hγ (1)
Here, η: viscosity of the underfill material, L: impregnation length, h: gap, γ: surface tension of the underfill material. As apparent from the formula (1), the lower the viscosity of the resin composition, the more advantageous in order to shorten the impregnation rate. However, when the viscosity is lowered, sedimentation of the filler contained in the epoxy resin composition becomes a problem. The settling velocity (V) of the filler is expressed by the following equation (2).
V = g (ρ _s −ρ) d ² / 18η (2)
Where, g: acceleration of gravity (cm / s ² ), ρ _s : filler density (g / cm ³ ), ρ: resin composition density (g / cm ³ ), d: diameter of filler (cm), η: Resin composition viscosity. From formula (2), it can be seen that in order to suppress sedimentation of the filler without changing the viscosity of the resin composition, it is necessary to make the particle size of the filler fine. However, the epoxy resin composition for underfill needs to have the same linear expansion coefficient as that of the bump material in order to ensure the reliability of the joint portion, and it is necessary to highly fill the filler. However, if the filler is highly filled or if the particle size is made fine in order to suppress sedimentation, there is a problem that the viscosity of the epoxy resin composition increases and the impregnation property decreases. Therefore, in the epoxy resin composition for underfill, the viscosity is lowered to increase the impregnation rate, the filler is finely divided to prevent the filler from being settled, and the filler is filled to reduce the thermal expansion. It was necessary to solve the problem at the same time.
Furthermore, since such an epoxy resin composition for underfill is impregnated into the gap between the element and the substrate under heat and cured by heating, voids remain (or occur) at the interface between the element, the substrate and the bump or inside the composition. However, when thermal stress is applied, interface peeling and cracks may occur, and the reduction of voids is also an important issue. In recent years, the chip size has been increased due to higher integration and multi-functionality of elements, while the bump diameter has been reduced and the pitch has been reduced by increasing the number of pins, resulting in a narrower gap between the chip and the substrate. Therefore, it has become more difficult to solve the above problems.

  The present invention has been made in view of such a situation, and has a liquid epoxy resin composition excellent in impregnation into a large area and a narrow gap, and less likely to cause sedimentation and voiding of a filler, and reliability using the resin composition. An object of the present invention is to provide an excellent electronic component device such as a semiconductor device.

As a result of intensive studies to solve the above problems, the present inventor has an epoxy resin, a curing agent, an inorganic filler as essential components, and a liquid accelerator resin composition containing a curing accelerator as necessary. Viscosity ratio η ₁ / η ₂ (hereinafter referred to as thixotropic index) measured at rotational speeds n ₁ and n ₂ (n ₁ / n ₂ <0.5) of the rotary viscometer is smaller than 0.8, in other words Then, by adding dilatancy to the liquid epoxy resin composition, by reducing the viscosity in the extremely low shear rate region where the liquid epoxy resin composition impregnates the gap between the element and the substrate by capillary action,
Further, preferably, by setting the average particle size of the inorganic filler within the range of 0.3 to 5 μm,
The inventors have found that the above object can be achieved and have completed the present invention.

That is, the present invention
(1) A solvent-free liquid epoxy resin composition comprising (A) an epoxy resin, (B) a curing agent and (C) an inorganic filler as essential components, and having a thixotropic index of less than 0.8 The present invention relates to a liquid epoxy resin composition.
Moreover, this invention relates to the liquid epoxy resin composition of the said (1) description whose average particle diameter of (2) (C) inorganic filler exists in the range of 0.3-5 micrometers.

The present invention also provides (3) the liquid epoxy resin composition according to the above (1) or (2), further containing (D) a curing accelerator,
(4) (A) Epoxy resin is bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, water-added bisphenol A type epoxy resin, naphthalenediol type epoxy resin, aminoglycidyl The liquid epoxy resin composition according to any one of the above (1) to (3), comprising at least one liquid epoxy resin selected from ether type epoxy resins,
(5) The liquid epoxy resin according to any one of the above (1) to (4), wherein the (B) curing agent contains at least one compound selected from a liquid acid anhydride, a liquid phenol resin, and a liquid aromatic amine. Relates to the composition.

In the present invention, (6) (C) the inorganic filler is spherical fused silica, and the blending amount (volume%) with respect to the whole composition is less than the closest packing fraction of the filler alone. The liquid epoxy resin composition according to any one of the above (1) to (5), wherein the liquid epoxy resin composition is in an amount greater than the ratio x 0.6
(7) The liquid epoxy resin composition according to (6), wherein 99% by weight or more of the fused silica has a particle size in the range of 0.1 μm to 16 μm.

Moreover, this invention is (8) any one of said (1)-(7) whose epoxy resin contains at least one of a liquid bisphenol F type epoxy resin and an aminoglycidyl ether type epoxy resin, and a hardening | curing agent is a liquid aromatic amine. The present invention relates to a crab liquid epoxy resin composition.
In the present invention, (9) the circuit formation surface of the element and the circuit formation surface of the inorganic or organic substrate face each other, and the electrode of the element and the circuit of the substrate are electrically connected via a bump, It is related with the electronic component apparatus characterized by filling the liquid epoxy resin composition in any one of said (1)-(8) in the clearance gap between an element and the said board | substrate.

  The liquid epoxy resin composition of the present invention is excellent in impregnation into narrow gaps, and causes little settling of filler and generation of voids. An electronic component device using this liquid epoxy resin composition for sealing an element has excellent moldability and good reliability such as reflow resistance, temperature cycle resistance, and moisture resistance, especially flip chip mounting type. It is suitably used for a semiconductor device.

An example of the flip chip mounting type semiconductor device using the liquid epoxy resin composition of the present invention as an underfill material is shown. An example of a method of impregnating a liquid epoxy resin composition in a gap between an element of a flip chip mounting type semiconductor device and a substrate will be described.

The (A) epoxy resin used in the present invention is not particularly limited. For example, glycidyl ether type epoxy resin obtained by reaction of bisphenol A, bisphenol F, bisphenol AD, bisphenol S, naphthalene diol, hydrogenated bisphenol A and the like with epichlorohydrin. , Epoxidized novolak resin obtained by condensation or cocondensation of phenols and aldehydes including orthocresol novolac type epoxy resin, obtained by reaction of polybasic acids such as phthalic acid and dimer acid with epichlorohydrin Glycidyl ester epoxy resin, diaminodiphenylmethane, isocyanuric acid and other polyamines and epichlorohydrin obtained by reaction of epichlorohydrin, olefinic bonds such as peracetic acid A linear aliphatic epoxy resin obtained by oxidation with alicyclic, an alicyclic epoxy resin, or the like can be used. In particular, in the present invention, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, naphthalene diol type epoxy resin, hydrogenated bisphenol A type epoxy resin, aminoglycidyl ether type epoxy resin It is desirable to include at least one liquid epoxy resin selected from the group consisting of at least one of liquid bisphenol F type epoxy resin and aminoglycidyl ether type epoxy resin.
These may be used alone or in combination of two or more.

Further, a solid epoxy resin may be used as long as the object of the invention is not impaired. Furthermore, you may mix the reactive diluent which has an epoxy group for viscosity adjustment. Examples of the reactive diluent having an epoxy group include n-butyl glycidyl ether, versatic acid glycidyl ether, styrene oxide, ethylhexyl glycidyl ether, phenyl glycidyl ether, butyl phenyl glycidyl ether, 1,6-hexanediol diglycidyl ether, neodymium Examples include pentyl glycol diglycidyl ether, diethylene glycol diglycidyl ether, and trimethylolpropane triglycidyl ether, and one or more of these may be used in combination.
These epoxy resins are sufficiently purified and preferably have little ionic impurities. For example, free Na ions and free Cl ions are preferably 500 ppm or less.

The (B) curing agent used in the present invention is not particularly limited, and acid anhydrides, phenol resins, aromatic amines, various imidazole derivatives and the like that are generally used as curing agents for epoxy resins can be used. From the viewpoint of viscosity increase, an acid anhydride, a phenol resin and an imidazole derivative from the viewpoint of storage stability, and an aromatic amine are more preferable from the viewpoint of moisture-resistant adhesion. Among these, it is particularly preferable to include at least one compound selected from a liquid acid anhydride, a liquid phenol resin, and a liquid aromatic amine, and a liquid aromatic amine is more preferable.
If the composition is liquid, the curing agent may be a solid compound, or a liquid and a solid compound may be used in combination.

  Examples of the acid anhydride include phthalic anhydride, tetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, hymic anhydride, succinic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. You may use it, or may use it in combination of 2 or more types.

  The phenol resin is not particularly limited as long as it has two or more phenolic hydroxyl groups in the molecule. For example, phenols such as phenol, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, etc. And / or a novolak-type phenol resin obtained by condensation or cocondensation of naphthols such as α-naphthol, β-naphthol and dihydroxynaphthalene with a compound having an aldehyde group such as formaldehyde under an acidic catalyst, and allylated bisphenol A Phenol synthesized from phenols such as allylated bisphenol F, allylated naphthalene diol, phenol novolac, phenol, and / or naphthol and dimethoxyparaxylene or bis (methoxymethyl) biphenyl Examples thereof include a nor-aralkyl resin and a naphthol-aralkyl resin. These may be used alone or in combination of two or more.

  As an aromatic amine, for example, EpiCure W, EpiCure Z (all trade names manufactured by Japan Epoxy Resin Co., Ltd.), Kayahard A-A, Kayahard AB, Kayahard AS (all manufactured by Nippon Kayaku Co., Ltd.) Name), Totoamine HM-205 (trade name, manufactured by Toto Kasei Co., Ltd.), Adeka Hardener EH-101 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), Epomic Q-640, Epomic Q-643 (all of which are Mitsui Chemicals, Inc.) Product name), DETDA80 (product name made by Lonza), and the like. These may be used alone or in combination of two or more.

  Examples of imidazole derivatives include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methyl. Imidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-pheno Ruimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazolium trimellitate, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4 -Zia Mino-6- [2'-methylimidazolyl- (1 ')]-ethyl-striazine, 2,4-diamino-6- (2'-undecylimidazolyl) -ethyl-s-triazine, 2,4-diamino -6- [2'-ethyl-4-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s -Triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxydimethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole 1-cyanoethyl-2-phenyl-4,5-di (2-cyanoethoxy) methylimidazole, and the like, May be used.

  The equivalent ratio of (A) epoxy resin and (B) curing agent is not particularly limited. Is preferably set to 0.7 to 1.4 equivalents, and more preferably 0.8 to 1.2 equivalents. 0.6. When deviating from the range of ˜1.6 equivalents, there is a tendency that unreacted components increase and reliability decreases.

  Here, the equivalent of phenol resin is calculated as one phenolic hydroxyl group reacts with one epoxy group, and the equivalent of aromatic amine is one amino group active hydrogen reacts with one epoxy group The equivalent of acid anhydride is calculated as one acid anhydride group reacts with one epoxy group. Since the imidazole derivative acts as a polymerization catalyst for the epoxy resin, the amount of the imidazole derivative is determined in consideration of the curing speed and pot life of the composition.

A feature of the liquid epoxy resin composition of the present invention is that the thixotropic index is less than 0.8, that is, it has a dilatancy. In the present invention, the thixotropic index indicates the viscosity ratio η ₁ / η ₂ measured at the rotational speeds n ₁ and n ₂ (n ₁ / n ₂ <0.5) of the rotary viscometer.
An inorganic filler plays an important role in imparting such properties to the epoxy resin composition, and the liquid epoxy resin composition of the present invention must contain (C) an inorganic filler. It is. Inorganic fillers are blended for the purpose of lowering the thermal expansion, imparting rigidity and thermal conductivity of the epoxy resin composition, and are usually fused silica, crystalline silica, alumina, silicon nitride, boron nitride, silicon carbide. In particular, it is preferable to use spherical fused silica in the present invention.
As the spherical fused silica, it is preferable to use substantially spherical fused silica produced by heat-treating natural or synthetic silica by a thermal spraying method or the like. Here, substantially spherical means the following. That is, when natural or synthetic silica is spheroidized by heat treatment, particles that are not completely melted may not be spherical. Further, there may be a case where a plurality of fused particles are fused. Furthermore, the evaporated silica vapor may adhere and solidify on the surface of other particles, and as a result, spherical silica particles having fine particles attached may be obtained. The term “substantially spherical” allows the mixture of particles having such a shape. For example, the sphericity of a particle is expressed by the Wadel sphericity [(diameter of a circle equal to the projected area of the particle) / (projection of particle)]. The diameter of the smallest circle circumscribing the image)] is preferably 90% by weight or more of the total inorganic filler.
Although the relationship between the properties of the inorganic filler and the dilatancy of the epoxy resin composition is not necessarily clear, the epoxy resin composition of the present invention has a resin component between the filler particles in an extremely low shear region, and the filler particles It is considered that the low-viscosity is exhibited because it is difficult to cause contact, and the filling form of the filler is changed in a high shear region where an external force acts, and the filler particles are easily brought into direct contact with each other to exhibit high viscosity.
Examples of the rotary viscometer include E type and B type, and are not particularly limited.
The rotation speeds n ₁ and n ₂ of the viscometer are not particularly limited as long as n ₁ / n ₂ <0.5, but preferably n ₁ is 0.5 to 5 rpm and n ₂ is 10 to 50 rpm. is there.

  The average particle size of the inorganic filler used in the liquid epoxy resin composition of the present invention is preferably in the range of 0.3 μm to 5 μm. The reason is that if the average particle size is too small, the increase in the specific surface area of the filler causes an increase in the viscosity of the epoxy resin composition and the development of thixotropic properties, making it impossible to increase the amount of filler and to provide dilatancy. Further, if the average particle size is too large, the impregnation property into a narrow gap is deteriorated, or a problem of sedimentation of the filler occurs.

In the liquid epoxy resin composition of the present invention, the blending amount (volume%) of the inorganic filler with respect to the entire composition is smaller than the closest packing fraction of the filler alone, and the closest packing fraction × 0.6. It is preferable that the amount be larger than that. The reason is as follows. When the blending ratio of the inorganic filler is equal to or greater than the close-packed fraction of the filler alone, the filler particles are always in contact with each other in the epoxy resin composition, and the viscosity of the composition rapidly increases. This is because it is not suitable for the purpose. Moreover, when the blending ratio of the inorganic filler is the closest packing fraction × 0.6 or less, even when an external force is applied to the epoxy resin composition, contact between the filler particles does not occur and dilatancy does not appear.
Here, the close-packed fraction of the single filler means the volume fraction of the filler occupying the molded body when the single filler is compression molded at a pressure of 5 to 10 MPa.

  In the liquid epoxy resin composition of the present invention, it is preferable that 99% by weight or more of the inorganic filler is in the range of 0.1 μm to 16 μm in particle size. This is because the viscosity of the epoxy resin composition increases as the number of components having a particle size of less than 0.1 μm increases, and the thixotropic property opposite to that of dilatancy appears. This is because the impregnation property into the water is reduced. The spherical fused silica produced by the thermal spraying method may contain a large amount of ultrafine particle components of less than 0.1 μm produced by cooling and solidifying the raw material vaporized in the thermal spraying process. Such spherical fused silica with many ultrafine particle components is not preferable because it increases the viscosity and thixotropic properties of the epoxy resin composition. The particle size distribution of the filler is not particularly limited as long as 99% by weight or more is in the range of 0.1 μm to 16 μm. However, in order to obtain a low-viscosity epoxy resin composition by increasing the blending amount of the filler, it is 0. It is desirable to use a filler having a particle size distribution as wide as possible within a particle size range of 1 μm to 16 μm. This is presumably because by expanding the particle size distribution, there is another particle in the gap between the particles, so that the close-packed fraction of the filler itself increases and contact between the filler particles hardly occurs.

If necessary, (D) a curing accelerator can be used in the resin composition of the present invention. In addition, a coupling agent, a flexing agent, a coloring agent, and the like can be used.
The (D) curing accelerator is not particularly limited as long as it accelerates the curing reaction between the (A) epoxy resin and the (B) curing agent, which is generally used in epoxy resin compositions. An imidazole compound such as 2-ethyl-4-methylimidazole, an organophosphine compound, a quaternary ammonium, or a phosphonium compound can be used. For example, 1,8-diazabicyclo [5.4.0] undecene-7,1,5-diazabicyclo [4.3.0] nonene-5,5,6-dibutylamino-1,8-diazabicyclo [5.4 .0] cycloamidine compounds such as undecene-7 and these compounds to maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethyl Quinones such as benzoquinone, 2,3-dimethoxy-5-methyl-1,4benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, phenyl-1,4-benzoquinone, π such as diazophenylmethane, phenol resin, etc. Compound with intramolecular polarization formed by adding a compound with bond, benzyldimethylamine, triethanolamine, dimethylamine Tertiary amines such as ethanol and tris (dimethylaminomethyl) phenol and their derivatives, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole and the like Derivatives thereof, phosphine compounds such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tris (4-methylphenyl) phosphine, diphenylphosphine, phenylphosphine, and other organic phosphines, and the quinone compounds and anhydrous maleic compounds. Phosphorus compounds with intramolecular polarization formed by adding compounds with π bonds such as acid, diazophenylmethane, phenol resin, tetraphenylphosphonium tetraphenylborate, tetraphenyl Tetraphenyl boron salts such as tetra-substituted phosphonium / tetra-substituted borate such as ruphosphonium ethyl triphenyl borate, tetrabutyl phosphonium tetrabutyl borate, 2-ethyl-4-methylimidazole / tetraphenyl borate, N-methylmorpholine / tetraphenyl borate And derivatives thereof. One of these may be used alone, or two or more thereof may be used in combination.
The coupling agent has an effect of improving the adhesion between the inorganic filler and the resin and the adherend. Specifically, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) ) Aminopropyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-anilinopropyltrimethoxysilane, γ-ureidotrimethoxysilane, γ-dibutylaminopropyltrimethoxysilane, imidazole Silane or the like can be used. Silicone and polyolefin-based elastomers or powders thereof can be used as the flexibilizing agent, and carbon black, organic dyes, organic pigments, titanium oxide, red lead, bengara, etc. can be used as the colorant.

The liquid epoxy resin composition obtained by the present invention includes LSIs, transistors, diodes, thyristors, and other active elements resin-sealed with ceramics, glass / epoxy, polyimide and other substrates, capacitors, resistors, passive elements such as coils, etc. At the same time, it is preferably used as an underfill material that impregnates a gap between a bare chip and a substrate such as a COB (Chip on Board), a module, or a card for flip chip mounting a bare semiconductor chip. Also, the gap between bare chip and board such as FC-BGA (Flip chip Ball Grid Array), EBGA (Enhanced BGA), ABGA (Advanced BGA), Stacked-BGA, SIP (System in Package) etc. It is preferable to use it as an underfill material to be impregnated. In particular, the chip size has recently been increased and the gap has been narrowed. The liquid epoxy resin composition of the present invention exhibits excellent effects when the chip size is 15 × 15 mm or more and the gap is 80 μm or less.
The latest packages such as BGA, CSP (Chip Size / Scale Package), and WL-CSP (Wafer Level CSP) have an area array structure, and the mounting form on the board is the same as flip chip mounting. is there. In particular, in mobile electronic devices such as mobile phones, the impact resistance of joints is strictly required, and a resin composition for reinforcement is impregnated in the gap between the package and the substrate in order to ensure connection reliability. is there. The liquid epoxy resin composition of the present invention can also be used for such applications. In addition, bare chips are wire-bonded to TCP (Tape Carrier Package), ceramics, glass / epoxy, polyimide substrates, etc., which have been conventionally sealed with liquid epoxy resin compositions and bonded to semiconductor tape via bumps. It can also be used for resin sealing of COB, module, card, BGA, CSP and the like mounted by the bonding method.
In particular, the flip chip mounting type in which the circuit forming surface of the element and the circuit forming surface of the inorganic or organic substrate are opposed to each other, and the electrode of the element and the circuit of the substrate are electrically connected via bumps, It is particularly preferred that the liquid epoxy resin composition is filled in the gap between the element and the substrate.
The liquid epoxy resin composition of the present invention can also be used effectively for printed circuit boards.

Although the manufacturing method of the liquid epoxy resin composition of this invention is not specifically limited, What is necessary is just the method which can disperse-mix the said various components uniformly. As a general method, dispersion kneading with a three-roll, a raking machine, a planetary mixer or the like can be mentioned. During mixing, the pressure may be reduced as necessary.
FIG. 1 is a schematic longitudinal sectional view of an example of a flip chip mounting type semiconductor device using the liquid epoxy resin composition of the present invention as an underfill material. FIG. 2 is a schematic longitudinal sectional view showing an example of a method for impregnating a liquid epoxy resin composition into a gap between an element of a flip chip mounting type semiconductor device and a substrate.
Resin sealing of a semiconductor element with the liquid epoxy resin composition of the present invention is usually performed by a dispensing method. For example, as shown in FIG. 2, a semiconductor device is prepared which is flip-chip mounted so that the circuit formation surface of the semiconductor chip 1 faces the circuit formation surface of the substrate 3 through bumps 2 such as solder balls. An underfill material 4 that is a liquid epoxy resin composition is dropped from a syringe 5 of a dispenser onto one side of the side surface of the chip 1 of the semiconductor device preheated on the hot plate 6. The underfill material 4 is impregnated in the direction of the arrow in FIG. 2 toward the opposite side surfaces of the chip 1 by capillary action. As a result, the gap between the chip 1 and the substrate 3 is filled with the underfill material 4. After completion of the impregnation, the resin composition is cured by heating the semiconductor device in a high-temperature bath, so that the intended resin-encapsulated semiconductor device (see FIG. 1) can be obtained.

EXAMPLES Next, although an Example demonstrates this invention further, the scope of the present invention is not limited to these Examples.
[Examples 1-7, Comparative Examples 1-5]
(A) As the epoxy resin, liquid bis-F type epoxy resin (epoxy resin 1: epoxy equivalent 160, [trade name YDF-8170C manufactured by Toto Kasei Co., Ltd.]), aminoglycidyl ether type epoxy resin (epoxy resin 2: epoxy) Equivalent 95, [trade name EP-630 manufactured by Japan Epoxy Resin Co., Ltd.), and a reactive diluent (epoxy equivalent 128, trade name SR-16HL manufactured by Sakamoto Pharmaceutical Co., Ltd.) were prepared.
(B) As a curing agent, liquid aromatic amine (curing agent 1: active hydrogen equivalent 45, [trade name Epicure W] manufactured by Japan Epoxy Resin Co., Ltd.), liquid acid anhydride (curing agent 2: acid equivalent 168, [ Hitachi Chemical Co., Ltd. product name HN5500]) was prepared.
(C) As the inorganic filler, inorganic fillers 1 to 6 having the characteristics shown in Table 1 and having substantially spherical composition and shape were prepared. In addition, each content of the particle | grains less than 0.1 micrometer and the particle | grains larger than 16 micrometers was calculated | required with the laser diffraction / scattering type particle size distribution measuring apparatus (model number LA-920) by HORIBA (Horiba Ltd.).
(D) 2-Ethyl-4-methylimidazole (hereinafter referred to as 2E4MZ) was prepared as a curing accelerator.
Epoxysilane (γ-glycidoxypropyltrimethoxysilane) was prepared as a coupling agent, and carbon black [trade name MA-600 manufactured by Mitsubishi Chemical Corporation] was prepared as a colorant.

[Examples 1-7]
These raw materials were weighed at the blending ratios shown in Table 2, put into a vacuum crusher, and kneaded for about 20 minutes while reducing the pressure to 5 torr to obtain 7 types of target liquid epoxy resin compositions.
Next, the semiconductor device on which the chip is mounted is placed on a hot plate preheated to 80 ° C., and the liquid epoxy resin composition is dropped onto one side surface of the chip of the semiconductor device using a dispenser, and the gap between the chip and the substrate is dropped. Was impregnated. After completion of the impregnation, the semiconductor device was heated in a high-temperature bath heated to 150 ° C. for 3 hours to cure the resin, thereby obtaining a desired resin-encapsulated semiconductor device.
The characteristics of the obtained liquid epoxy resin composition, the moldability of the semiconductor device, and the reliability were evaluated as follows. The evaluation results are summarized in Table 2 and written together.

  Measurement of the closest packing fraction of the used inorganic filler, various characteristics of the obtained liquid epoxy resin composition, and evaluation of the reliability of the semiconductor device are performed by the following methods and conditions (1) to (8). It was. The specifications of the used semiconductor device are: chip size 10 × 10 × 0.55 tmm (circuit is aluminum zigzag wiring, passivation: polyimide film), bump: solder ball (Φ80 μm, 916pin), bump pitch: 250 μm, substrate: FR-5 (40 × 40 × 0.8 tmm), chip / substrate gap: 60 μm. In addition, in order to evaluate moldability under more severe conditions, in the following evaluations (5) to (7), a large chip of 20.5 × 20.5 × 0.55 tmm in which the four chips are one chip is used. used.

(1) Close-packed fraction of inorganic filler
A cylindrical molded body was manufactured by filling a 10 mmφ × 50 mmL mold with about 3 g of an inorganic filler and compression molding by uniaxial pressing at a pressure of 7 MPa. The weight and volume (area × height) of this molded body were determined. The closest packing fraction (%) is the following formula (3)
Closest packing fraction (%) = {(W / D) / V} × 100 (3)
I asked for it. Here, W is the weight of the molded body, D is the density of the inorganic filler (fused silica is 2.21), and V is the volume of the molded body.
The obtained compact was crushed and the average particle size of the inorganic filler after compression molding was measured. The average particle size of the inorganic filler before molding was the same as the average particle size of the inorganic filler before molding. It was confirmed that the inorganic filler was not crushed during molding. In the present invention, the average particle diameter was determined by the above-mentioned laser diffraction / scattering particle size distribution measuring apparatus (LA-920) manufactured by HORIBA.

(2) Viscosity and thixotropic index Using an E-type viscometer (manufactured by Tokyo Keiki Co., Ltd.), the viscosity (Pa · s) at 25 ° C. of the liquid epoxy resin composition was measured at a rotor rotation speed of 10 rpm. The thixotropic index was expressed as the ratio of the viscosity measured at 2.5 rpm of the rotor and the viscosity measured at 10 rpm.

(3) Glass transition temperature and linear expansion coefficient The liquid epoxy resin composition was heat-molded into a cylindrical shape having a diameter of 4 mm and a length of 20 mm at 150 ° C. for 3 hours, and a thermomechanical analyzer TMA8140 (trade name, manufactured by Rigaku Corporation) was used. The amount of thermal expansion was measured at a heating rate of 3 ° C./min and a measurement temperature range of −120 to 250 ° C., and the intersection of the tangent of the straight line on the low temperature side and the tangent line of the high temperature side was taken as the glass transition temperature. The slope of the straight line was expressed as the linear expansion coefficient.
(4) Elastic modulus The liquid epoxy resin composition was heat-molded into a 0.4 mm thick sheet at 150 ° C. for 3 hours, and this sheet was cut into a 5 mm × 30 mm strip to obtain a dynamic viscoelasticity. Using a measuring device DVE type (manufactured by Rheology Co., Ltd.), the dynamic viscoelastic property was measured at a temperature rising rate of 3 ° C./min, a measurement temperature of −120 to 250 ° C., and a frequency of 10 Hz, and an elastic modulus (GPa) at 25 ° C. Read.

(5) Impregnation time As shown in FIG. 2, the semiconductor device on which the chip (20.5 × 20.5 × 0.55 tmm) is mounted is placed on a hot plate heated to 80 ° C., and is liquid using a dispenser. A predetermined amount of the epoxy resin composition was dropped on the side surface (one side) of the chip, and the time required for the epoxy resin composition to underfill between the chip and the substrate and penetrate into the opposing side surface was measured.

(6) Filler sedimentation observation The central part of the resin-encapsulated semiconductor device was cut in the longitudinal direction with a diamond cutter and the cut surface was polished smoothly, and then observed with a microscope VH6110 (trade name, manufactured by Keyence Corporation). The presence or absence of sedimentation of the filler was examined.

(7) Void Observation The inside of the resin-encapsulated semiconductor device was observed with an ultrasonic flaw detector AT-5500 (trade name, manufactured by Hitachi Construction Machinery Co., Ltd.) to examine the presence or absence of voids.

(8) Reliability evaluation
(1) Reflow resistance After the resin-encapsulated semiconductor device is heated and dried at 120 ° C. for 12 hours, the resin-encapsulated semiconductor device is moisture-absorbed for 168 hours at 85 ° C. and 60% RH, and the far-infrared heating type reflow oven (245 ° C. heating time 10 seconds) ) After passing through the inside three times, the inside was observed with an ultrasonic flaw detector, and the presence or absence of peeling of the liquid epoxy resin composition from the chip and the substrate and cracking of the epoxy resin composition were examined.

(2) Thermal cycle resistance Resin-encapsulated semiconductor devices are processed for 1000 cycles with a heat cycle of -50 ° C to 150 ° C for 30 minutes each, continuity tests are conducted to check for disconnection defects in aluminum wiring, and the number of defective packages / evaluation Evaluated by the number of packages.

(3) Moisture resistance reliability After processing the resin-encapsulated semiconductor device for 240 hours under PCT conditions of 121 ° C, 2 atm, 100% RH, the presence or absence of disconnection of the aluminum wiring and pads is confirmed by continuity test, and the number of defective packages / number of evaluation packages It was evaluated with.

[Comparative Examples 1-5]
Five types of liquid epoxy resin compositions were prepared in the same manner as in the above example except that each material weighed at the blending ratio shown in Table 3 was used, and various characteristics, moldability and reliability of the semiconductor device were evaluated. The results are summarized in Table 3 and shown together.

  As is clear from Tables 2 and 3, the liquid epoxy resin composition of the present invention is excellent in impregnation into narrow gaps, and the sedimentation of the filler and the generation of voids are small.

1 chip 2 bump (solder ball)
3 Substrate 4 Underfill material 5 Syringe 6 Hot plate

Claims (9)

  A solvent-free liquid epoxy resin composition comprising (A) an epoxy resin, (B) a curing agent and (C) an inorganic filler as essential components, and having a thixotropic index of less than 0.8 Epoxy resin composition.   (C) The liquid epoxy resin composition of Claim 1 which has the average particle diameter of an inorganic filler in the range of 0.3-5 micrometers.   (D) The liquid epoxy resin composition of Claim 1 or 2 which further contains a hardening accelerator.   (A) Epoxy resin is bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, water-added bisphenol A type epoxy resin, naphthalenediol type epoxy resin, aminoglycidyl ether type epoxy The liquid epoxy resin composition in any one of Claims 1-3 containing the at least 1 sort (s) of liquid epoxy resin chosen from resin.   (B) The liquid epoxy resin composition in any one of Claims 1-4 in which a hardening | curing agent contains the at least 1 sort (s) of compound chosen from a liquid acid anhydride, a liquid phenol resin, and a liquid aromatic amine.   (C) The inorganic filler is spherical fused silica, and the blending amount (% by volume) with respect to the entire composition is less than the closest packing fraction of the filler alone, and more than the closest packing fraction × 0.6. The liquid epoxy resin composition according to any one of claims 1 to 5, which is an amount.   The liquid epoxy resin composition according to claim 6, wherein 99% by weight or more of the fused silica has a particle size in the range of 0.1 µm to 16 µm. The epoxy resin includes at least one of a liquid bisphenol F type epoxy resin and an aminoglycidyl ether type epoxy resin,
The liquid epoxy resin composition according to claim 1, wherein the curing agent is a liquid aromatic amine. The circuit forming surface of the element and the circuit forming surface of the inorganic or organic substrate face each other, and the electrode of the element and the circuit of the substrate are electrically connected via a bump, and the gap between the element and the substrate is charged. Item 9. An electronic component device filled with the liquid epoxy resin composition according to any one of Items 1 to 8.