Underfill material, semiconductor package, and method of manufacturing semiconductor package

Abstract

To provide an underfill material that can suppress an increase in the thermal expansion coefficients of a cured product and reduce the viscosity during its filling, and a semiconductor package obtained by using the same and a method for producing the same.SOLUTION: An underfill material contains epoxy resin, a curing agent, and a filler, the epoxy resin including an epoxy compound having the structure of N,N-diglycidylaniline.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an underfill material, a semiconductor package, and a method for manufacturing the semiconductor package. [Background technology]

[0002] In the packaging technology of semiconductor devices, a liquid underfill material is widely used to fill the gap between the substrate and the semiconductor chip. For example, Patent Document 1 describes a liquid encapsulant that achieves good injectability and suppresses fillet cracks after encapsulation by blending a specific amount of aminophenol epoxy resin with bisphenol epoxy resin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 093148 Summary of the Invention [Problem to be solved by the invention]

[0004] Underfill materials generally contain a filler, but increasing the amount of filler tends to increase the viscosity of the underfill material and reduce its injectability. Therefore, attempts have been made to lower the viscosity by incorporating an epoxy resin known as a reactive diluent. However, increasing the amount of reactive diluent tends to increase the thermal expansion coefficient of the cured underfill material. A high thermal expansion coefficient of the cured underfill material increases the difference with the thermal expansion coefficient of the semiconductor chip, which can lead to defects in reliability tests such as reflow resistance and temperature cycle resistance, and can increase the amount of warping in the semiconductor device. Therefore, there is a need to design an underfill material that can reduce viscosity during filling while suppressing an increase in the coefficient of thermal expansion of the cured product. In view of the above circumstances, an object of the present invention is to provide an underfill material that can suppress an increase in the thermal expansion coefficient of the cured product while reducing viscosity during filling, as well as a semiconductor package obtained using the same and a method for manufacturing the same. [Means for solving the problem]

[0005] <1> An underfill material comprising an epoxy resin, a curing agent, and a filler, wherein the epoxy resin comprises an epoxy compound represented by the following general formula (1):

[0006] [ka]

[0007] [In general formula (1), R represents a hydrocarbon group having 1 to 5 carbon atoms. n represents the number of R and is an integer of 0 to 5.]

[0008] <2> The content of the filler is 60 mass % or more of the total underfill material. <1> The underfill material according to claim 1.

[0009] <3> The epoxy compound represented by the general formula (1) includes an epoxy resin in which R is a methyl group and n is 1. <1> or <2> The underfill material according to claim 1.

[0010] <4> The content of the epoxy compound represented by the general formula (1) is 1% by mass to 30% by mass of the total underfill material. <1> ~ <3> The underfill material according to any one of the preceding claims.

[0011] <5> the epoxy resin comprises at least one selected from the group consisting of bisphenol-based epoxy resins, naphthalene-based epoxy resins, and tri- or higher functional glycidylamine-based epoxy resins; <1> ~ <4> The underfill material according to any one of claims 1 to 10.

[0012] <6> the curing agent is an amine curing agent; <1> ~ <5> The underfill material according to any one of claims 1 to 10.

[0013] <7> a support, a semiconductor element disposed on the support, and a semiconductor element encapsulated therein <1> ~ <6> A semiconductor package comprising the cured underfill material according to any one of claims 1 to 4.

[0014] <8> A gap between the support and the semiconductor element disposed on the support is formed. <1> ~ <6> 10. A method for manufacturing a semiconductor package, comprising the steps of: filling with the underfill material according to any one of claims 1 to 9; and hardening the underfill material. [Effects of the Invention]

[0015] According to the present invention, there are provided an encapsulating resin composition that can suppress an increase in the coefficient of thermal expansion of the cured product and reduce the viscosity during filling, as well as a semiconductor package obtained using the same and a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments 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, components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the present invention.

[0017] In the present disclosure, the term "process" includes not only a process that is independent of other processes, but also a process that cannot be clearly distinguished from other processes as long as the purpose of the process is achieved. In the present disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples. In the present disclosure, each component may contain multiple substances corresponding to the component. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, the composition may contain multiple types of particles corresponding to each component. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

[0018] <Underfill material> The underfill material of the present embodiment contains an epoxy resin, a curing agent, and a filler, and the epoxy resin contains an epoxy compound (hereinafter also referred to as a specific epoxy resin) represented by the following general formula (1):

[0019] [ka]

[0020] In the general formula (1), R represents a hydrocarbon group having 1 to 5 carbon atoms, and n represents the number of R and is an integer of 0 to 5.

[0021] As a result of studies by the present inventors, it was found that an underfill material containing a specific epoxy resin can suppress an increase in the coefficient of thermal expansion of the cured product and reduce the viscosity during filling. The reason for this is not clear, but it is thought to be because the specific epoxy resin blended into the epoxy resin has the property of acting as a reactive diluent to reduce the viscosity of the underfill material, and also has the property of making the coefficient of thermal expansion of the cured product less likely to increase compared to when epoxy resins used as other reactive diluents are blended. Underfill materials containing specific epoxy resins can suppress an increase in the thermal expansion coefficient of the cured product while reducing viscosity during filling. For example, this makes it possible to increase the amount of filler while suppressing an increase in viscosity.

[0022] The underfill material preferably has a sufficiently low viscosity when filling the gap between the substrate and the semiconductor chip. Specifically, the viscosity at 110°C is preferably 1.0 Pa·s or less, more preferably 0.75 Pa·s or less, and even more preferably 0.50 Pa·s or less. In this disclosure, the viscosity of the underfill material at 110°C is measured using a rheometer (e.g., the "AR2000" manufactured by TA Instruments Japan Co., Ltd.) with 40 mm parallel plates at a shear rate of 32.5 / sec.

[0023] [Epoxy resin] The epoxy resin is not particularly limited as long as it contains the specific epoxy resin represented by general formula (1). The specific epoxy resin may be used alone or in combination of two or more types.

[0024] In general formula (1), examples of the hydrocarbon group having 1 to 5 carbon atoms represented by R include an alkyl group having 1 to 5 carbon atoms and an alkenyl group having 1 to 5 carbon atoms, with an alkyl group having 1 to 5 carbon atoms being preferred, an alkyl group having 1 to 3 carbon atoms being more preferred, and a methyl group being even more preferred.

[0025] In general formula (1), n ​​is preferably an integer of 0 to 3, more preferably 0 or 1, and even more preferably 1.

[0026] In general formula (1), when n is 1 or more, it is preferable that any one of the one or more Rs is in the ortho position relative to the diglycidylamino group.

[0027] Specific examples of the specific epoxy resin include a compound in which n is 0 (N,N-(diglycidyl)-aniline), a compound in which R is a methyl group in the ortho position relative to the diglycidylamino group and n is 1 (N,N-(diglycidyl)-o-toluidine), and the like. These are also available as commercially available products. An example of a commercially available N,N-(diglycidyl)-aniline product is "GAN" manufactured by Nippon Kayaku Co., Ltd., and an example of a commercially available N,N-(diglycidyl)-o-toluidine product is "ADEKA RESIN EP-3980S" manufactured by ADEKA Corporation and "GOT" manufactured by Nippon Kayaku Co., Ltd.

[0028] From the viewpoint of simultaneously suppressing an increase in the coefficient of thermal expansion of the cured product and reducing the viscosity during filling, the content of the specific epoxy resin is preferably 1% by mass to 50% by mass, and more preferably 5% by mass to 30% by mass, of the total epoxy resin.

[0029] When the epoxy resin contains an epoxy resin other than the specific epoxy resin, the epoxy resin other than the specific epoxy resin is not particularly limited. Examples include bisphenol-type epoxy resins, naphthalene-type epoxy resins, glycidylamine-type epoxy resins, hydrogenated bisphenol-type epoxy resins, alicyclic epoxy resins, alcohol ether-type epoxy resins, cycloaliphatic epoxy resins, fluorene-type epoxy resins, and siloxane-based epoxy resins. The epoxy resins other than the specific epoxy resin may be used alone or in combination of two or more.

[0030] Among the above epoxy resins, it is preferable to include at least one selected from the group consisting of bisphenol-type epoxy resins, naphthalene-type epoxy resins, and tri- or higher-functional glycidylamine-type epoxy resins, and it is more preferable to include each of bisphenol-type epoxy resins, naphthalene-type epoxy resins, and tri- or higher-functional glycidylamine-type epoxy resins.

[0031] The type of bisphenol epoxy resin is not particularly limited, and examples thereof include bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol AD ​​epoxy resin. For use as an underfill material, the bisphenol epoxy resin is preferably liquid at room temperature (25°C), and more preferably a bisphenol F epoxy resin that is liquid at room temperature (25°C). Bisphenol epoxy resins that are liquid at room temperature (25°C) are also available as commercial products. An example of a commercial bisphenol F epoxy resin that is liquid at room temperature (25°C) is "Epotohto YDF-8170C" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.

[0032] The proportion of the bisphenol-type epoxy resin in the total epoxy resin is not particularly limited and can be selected depending on the desired properties of the underfill material, for example, in the range of 20% to 90% by mass.

[0033] The type of naphthalene-type epoxy resin is not particularly limited. The naphthalene-type epoxy resin used in the underfill material is preferably liquid at room temperature (25°C). An example of a naphthalene-type epoxy resin that is liquid at room temperature (25°C) is 1,6-bis(glycidyloxy)naphthalene. 1,6-bis(glycidyloxy)naphthalene is also available as a commercially available product. An example of a commercially available product is "Epiclon HP-4032D" manufactured by DIC Corporation.

[0034] When the underfill material contains a naphthalene-type epoxy resin as the epoxy resin, the proportion of the naphthalene-type epoxy resin is not particularly limited. For example, the proportion of the naphthalene-type epoxy resin in the total epoxy resin is preferably 10% by mass or more from the viewpoint of suppressing an increase in the thermal expansion coefficient, and is preferably 50% by mass or less from the viewpoint of balancing the properties of the underfill material.

[0035] The type of tri- or higher functional glycidylamine epoxy resin is not particularly limited. The tri- or higher functional glycidylamine epoxy resin used as the underfill material is preferably liquid at room temperature (25° C.).

[0036] An example of a trifunctional or higher glycidylamine epoxy resin that is liquid at room temperature (25°C) is triglycidyl-p-aminophenol. Triglycidyl-p-aminophenol is also available as a commercially available product. Examples of commercially available products include "jER-630" and "jER-630LSD" from Mitsubishi Chemical Corporation, and "EP-3950S" from ADEKA Corporation.

[0037] When the underfill material contains a tri- or higher functional glycidylamine epoxy resin as the epoxy resin, the proportion of the epoxy resin is not particularly limited. For example, from the viewpoint of improving heat resistance, the proportion of the epoxy resin in the total epoxy resin is preferably 10% by mass or more, and from the viewpoint of balancing the properties of the underfill material, it is preferably 50% by mass or less.

[0038] [Hardening agent] The type of curing agent is not particularly limited and can be selected depending on the desired properties of the underfill material. Examples include amine curing agents, phenolic curing agents, acid anhydride curing agents, polymercaptan curing agents, polyaminoamide curing agents, isocyanate curing agents, and blocked isocyanate curing agents. One type of curing agent may be used alone, or two or more types may be used in combination.

[0039] The curing agent used in the underfill material is preferably liquid at room temperature (25°C), and from the viewpoint of adhesion to the substrate, an amine curing agent is preferable. Examples of amine curing agents include aliphatic amine compounds such as diethylenetriamine, triethylenetetramine, n-propylamine, 2-hydroxyethylaminopropylamine, cyclohexylamine, and 4,4'-diamino-dicyclohexylmethane; aromatic amine compounds such as diethyltoluenediamine, 3,3'-diethyl-4,4'-diaminodiphenylmethane, and 2-methylaniline; imidazole compounds such as imidazole, 2-methylimidazole, 2-ethylimidazole, and 2-isopropylimidazole; and imidazoline compounds such as imidazoline, 2-methylimidazoline, and 2-ethylimidazoline. Among these, aromatic amine compounds are preferable.

[0040] The compounding ratio of the epoxy resin and the curing agent is preferably set so that the ratio of the number of functional groups of the curing agent (active hydrogen in the case of an amine curing agent) to the number of epoxy groups of the epoxy resin (number of functional groups of the curing agent / number of epoxy groups of the epoxy resin) is within the range of 0.5 to 2.0, more preferably 0.6 to 1.3, in order to minimize unreacted components, and even more preferably 0.8 to 1.2, in terms of moldability and reflow resistance.

[0041] [Filler] The type of filler is not particularly limited. Specific examples include inorganic materials such as silica, glass, alumina, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, boron nitride, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, talc, clay, and mica. A filler having a flame-retardant effect may also be used. Examples of the flame-retardant filler include aluminum hydroxide, magnesium hydroxide, composite metal hydroxides such as a magnesium-zinc composite hydroxide, and zinc borate.

[0042] Among the above fillers, silica is preferred from the viewpoint of reducing the coefficient of thermal expansion, and alumina is preferred from the viewpoint of improving thermal conductivity. The fillers may be used alone or in combination of two or more.

[0043] The filler content in the underfill material is not particularly limited. From the viewpoint of reducing the thermal expansion coefficient after curing, the higher the filler content, the better. For example, it is preferably 60% by mass or more of the entire underfill material, and more preferably 64% by mass or more. On the other hand, from the viewpoint of suppressing an increase in viscosity, the lower the filler content, the better. For example, it is preferably 90% by mass or less of the entire underfill material.

[0044] When the filler is particulate, its average particle diameter is not particularly limited. For example, the volume average particle diameter is preferably 0.05 μm to 20 μm, and more preferably 0.1 μm to 15 μm. When the volume average particle diameter is 0.05 μm or more, an increase in viscosity of the underfill material tends to be further suppressed. When the volume average particle diameter is 20 μm or less, the filling ability into narrow gaps tends to be further improved. The volume average particle diameter of the filler can be measured as the particle diameter (D50) at which the cumulative volume from the small diameter side reaches 50% in the volume-based particle size distribution obtained using a laser scattering diffraction particle size distribution analyzer.

[0045] [Various additives] In addition to the components described above, the underfill material may contain various additives such as a curing accelerator, a stress relief agent, a coupling agent, a colorant, etc. In addition to the additives exemplified below, the underfill material may also contain various additives known in the art as needed.

[0046] (curing accelerator) The underfill material may contain a curing accelerator. The type of curing accelerator is not particularly limited and can be selected depending on the types of epoxy resin and curing agent, the desired properties of the underfill material, and the like.

[0047] When the underfill material contains a curing accelerator, the amount thereof is preferably 0.1 to 30 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of the curable resin component (total of epoxy resin and curing agent).

[0048] (stress reliever) The underfill material may contain a stress relaxation agent. Examples of the stress relaxation agent include particles of thermoplastic elastomer, NR (natural rubber), NBR (acrylonitrile-butadiene rubber), acrylic rubber, urethane rubber, silicone rubber, etc. One type of stress relaxation agent may be used alone, or two or more types may be used in combination.

[0049] When the underfill material contains a stress relaxation agent, the amount thereof is preferably 0.1 to 30 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of the curable resin component (total of epoxy resin and curing agent).

[0050] (coupling agent) The underfill material may contain a coupling agent. Examples of coupling agents include silane compounds such as epoxysilane, phenylsilane, mercaptosilane, aminosilane, phenylaminosilane, alkylsilane, ureidosilane, and vinylsilane, titanium compounds, aluminum chelate compounds, and aluminum / zirconium compounds. Among these, silane compounds (silane coupling agents) are preferred. The coupling agents may be used alone or in combination of two or more.

[0051] When the underfill material contains a coupling agent, the amount of the coupling agent is preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 2.5 parts by mass, per 100 parts by mass of the filler.

[0052] (coloring agent) The underfill material may contain a colorant, such as carbon black, organic dye, organic pigment, titanium oxide, red lead, or red iron oxide. The colorant may be used alone or in combination of two or more.

[0053] When the underfill material contains a colorant, the amount thereof is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the curable resin component (total of epoxy resin and curing agent).

[0054] (Underfill material applications) The underfill material can be used in various mounting techniques, and is particularly suitable as an underfill material for use in flip-chip mounting techniques, for example, to fill gaps between a semiconductor element and a support that are joined by bumps or the like.

[0055] The types of the semiconductor element and the support are not particularly limited and can be selected from those commonly used in the field of semiconductor packaging. The method of filling the gap between the semiconductor element and the support with the underfill material is not particularly limited. For example, it can be carried out by a known method using a dispenser or the like.

[0056] <Semiconductor package> The semiconductor package of this embodiment includes a support, a semiconductor element placed on the support, and the cured underfill material described above that seals the semiconductor element.

[0057] In the semiconductor package, the types of the semiconductor element and the support are not particularly limited and can be selected from those commonly used in the field of semiconductor packages. Since the semiconductor package has a reduced thermal expansion coefficient of the cured underfill material, it is effective in suppressing stress, for example, if stress occurs between the cured underfill material and the semiconductor element.

[0058] <Semiconductor package manufacturing method> The method for manufacturing a semiconductor package of this embodiment includes a step of filling a gap between a support and a semiconductor element arranged on the support with the above-mentioned underfill material, and a step of hardening the underfill material.

[0059] In the above method, the types of the semiconductor element and the support are not particularly limited and can be selected from those commonly used in the field of semiconductor packaging. The method of filling the gap between the semiconductor element and the support with an underfill material and the method of curing the underfill material after filling are not particularly limited and can be performed by known techniques. [Example]

[0060] The underfill material of the present disclosure will be specifically described below using examples, but the scope of the present disclosure is not limited to these examples.

[0061] (Preparation of underfill material) An underfill material was prepared by mixing the components shown in Table 1 in the amounts (parts by mass) shown in Table 1. Details of each component are as follows. The mixing ratio of the epoxy resin and curing agent was set so that the number of epoxy groups in the epoxy resin was equal to the number of active hydrogens in the curing agent.

[0062] Epoxy resin 1: Liquid bisphenol F epoxy resin, epoxy equivalent: 160g / eq, product name "Epotohto YDF-8170C", Nippon Steel & Sumikin Chemical Co., Ltd. Epoxy resin 2: Triglycidyl-p-aminophenol, epoxy equivalent: 95g / eq, product name "jER 630", Mitsubishi Chemical Corporation Epoxy resin 3: 1,6-bis(glycidyloxy)naphthalene, epoxy equivalent: 143g / eq, product name "Epiclon HP-4023D", DIC Corporation

[0063] Epoxy resin 4: N,N-(diglycidyl)-o-toluidine, epoxy equivalent: 115g / eq, product name "ADEKA RESIN EP-3980S", ADEKA Corporation Epoxy resin 5: 1,4-butanediol diglycidyl ether, epoxy equivalent: 102g / eq, product name "SR-14BJ", Sakamoto Pharmaceutical Co., Ltd. Epoxy resin 6: Trimethylolpropane triglycidyl ether, epoxy equivalent: 120, product name "Epotohto ZX-1542", Nippon Steel & Sumikin Chemical Co., Ltd.

[0064] Curing agent 1: Diethyltoluenediamine, product name "jER Cure W", active hydrogen equivalent: 45g / eq, Mitsubishi Chemical Corporation Curing agent 2: 3,3'-diethyl-4,4'-diaminodiphenylmethane, product name "Kayahard AA", active hydrogen equivalent: 63g / eq, Nippon Kayaku Co., Ltd.

[0065] Filler: Spherical silica with a volume average particle size of 0.5 μm, product name "SE2200", Admatechs Co., Ltd. Coupling agent: 3-glycidoxypropyltrimethoxysilane, product name "Sila-Ace S510", JNC Corporation Colorant: Carbon black, product name "MA-100", Mitsubishi Chemical Corporation

[0066] (Viscosity measurement at 110°C) The viscosity of the underfill material was measured using a rheometer (TA Instruments Japan, AR2000) with 40 mm parallel plates at a shear rate of 32.5 / sec at 110°C.

[0067] (Measurement of thermal expansion coefficient) The underfill material was heat-molded into a cylindrical shape with a diameter of 8 mm and a length of 20 mm at 150°C for 2 hours, and the cured product was measured using a TMA (thermomechanical analysis, TA4000SA manufactured by TA Instruments) at a heating rate of 3°C / min over a temperature range of 0 to 250°C. The gradient of the straight line from 0 to 30°C was taken as the linear expansion coefficient.

[0068] [Table 1]

[0069] As shown in Table 1, the underfill materials containing the specific epoxy resin had lower viscosity values ​​at 110°C when compared with underfill materials with the same filler content but not containing the specific epoxy resin (Examples 1 and 2 vs. Comparative Example 1, Examples 3 to 5 vs. Comparative Example 6, Examples 6 to 8 vs. Comparative Examples 7 and 8).Furthermore, the underfill materials containing the specific epoxy resin had lower thermal expansion coefficients of the cured products when compared with underfill materials with the same filler content but containing an epoxy resin commonly used as a reactive diluent (Examples 1 and 2 vs. Comparative Examples 2 to 5). From the above, it was found that by blending a specific epoxy resin as the epoxy resin, it is possible to reduce the viscosity during filling while suppressing an increase in the thermal expansion coefficient of the cured underfill material.

Claims

1. An underfill material (excluding those containing polyimide resin and polyethersulfone resin having a weight average molecular weight of 30,000 or more) comprising an epoxy resin, a curing agent, and a filler, wherein the epoxy resin comprises N,N-(diglycidyl)-o-toluidine, a bisphenol-based epoxy resin, a naphthalene-based epoxy resin, and a tri- or higher functional glycidylamine-based epoxy resin, and wherein the proportion of N,N-(diglycidyl)-o-toluidine in the entire epoxy resin is 5% by mass to 25% by mass, and the proportion of the bisphenol-based epoxy resin is 20% by mass to 45% by mass.

2. The underfill material according to claim 1 , wherein the filler content is 60% by mass or more of the total underfill material.

3. 3. The underfill material according to claim 1, wherein the content of the N,N-(diglycidyl)-o-toluidine is 1% by mass to 30% by mass of the total underfill material.

4. The underfill material according to any one of claims 1 to 3, wherein the curing agent is an amine curing agent.

5. A semiconductor package comprising: a support; a semiconductor element disposed on the support; and a cured product of the underfill material according to any one of claims 1 to 4, which seals the semiconductor element.

6. A method for manufacturing a semiconductor package, comprising: a step of filling a gap between a support and a semiconductor element placed on the support with the underfill material according to any one of claims 1 to 4; and a step of hardening the underfill material.

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