Liquid compression mold material

Abstract

To provide a liquid epoxy resin composition which has appropriate rheological characteristics, does not leak from a mold when attached to compression molding, and allows easy and efficient sealing of a semiconductor device.SOLUTION: A liquid compression mold material (LCM material) includes epoxy resin, curing agent, and a filler, and has 0.8 to 4.0 thixotropic index (TI). When TU of the LCM material is below 0.8, the extended LCM material reaches a metal inner surface in a very short time, and the LCM material floods from a mold before the mold closes completely. When TI of the LCM material is appropriate, a time required for the extended LCM material to reach the mold inner surface is longer than the former case. As a result, the extended LCM material reaches the mold inner surface after the mold closes completely, and leakage of the LCM material from the mold is avoided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a liquid compression molding material that can be suitably used in the manufacture of electronic components. [Background technology]

[0002] Many semiconductor elements, such as integrated circuits, are encapsulated with encapsulants. While there are several molding methods for encapsulating semiconductor elements, in recent years compression molding, which is more suitable for producing relatively large molded products, has been increasingly used to encapsulate semiconductor elements. This is due to the increasing popularity of wafer-level chip-size packaging technology (which involves encapsulating wafers that have completed circuit formation but have not yet been cut into chips).

[0003] Conventional curable resin compositions used for encapsulating semiconductor elements by compression molding have mainly been solid resin compositions such as granular ones. However, recently, with the development of new compression molding techniques, liquid curable resin compositions have been increasingly used. Hereinafter, such liquid curable resin compositions used for encapsulation by compression molding will be referred to as "liquid compression molding materials." These "liquid compression molding materials" may also be abbreviated as "LCM (Liquid Compression Molding) materials."

[0004] Liquid epoxy resin compositions are often used as liquid compression molding (LCM) materials from the viewpoint of a balance of various properties such as electrical properties, moisture resistance, heat resistance, mechanical properties, adhesiveness, etc. An example of an epoxy resin composition used as an LCM material is the liquid resin composition described in Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Application Publication No. WO2018 / 221681 [Patent Document 2] Patent Publication No. 2015-105304 Summary of the Invention [Problem to be solved by the invention]

[0006] However, it was discovered that when conventional LCM materials are subjected to compression molding, they leak from the mold joints, resulting in molding defects. This leakage reduces molding efficiency and causes loss of LCM material, resulting in increased manufacturing costs.

[0007] In order to solve the above-mentioned problems of the conventional art, an object of the present invention is to provide a liquid epoxy resin composition suitable for use as an LCM material, which has suitable rheological properties, does not leak from the mold even when subjected to compression molding, and enables easy and efficient encapsulation of semiconductor elements. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems and have arrived at the present invention.

[0009] That is, the present invention includes, but is not limited to, the following inventions.

[0010] 1. A liquid compression molding material comprising the following components (A) to (C): (A) Epoxy resin; (B) a curing agent; and (C) Filler and A liquid compression molding material with a thixotropic index (TI) of 0.8 to 4.0.

[0011] 2. The liquid compression molding material according to item 1 above, wherein component (C) contains particles having a particle size of 5 nm to 100 nm in an amount of 5 to 23 wt % based on the total weight of component (C).

[0012] 3. A liquid compression molding material according to item 2 above, which can be obtained by a method including a step of premixing at least a portion of the particles having a particle size of 5 nm to 100 nm in component (C) with at least a portion of component (A).

[0013] 4. The liquid compression molding material according to any one of items 1 to 3 above, wherein component (C) has been surface-treated with a coupling agent.

[0014] 5. The liquid compression molding material according to any one of items 1 to 4 above, having a viscosity at 25°C of 10 to 1000 Pa·s.

[0015] 6. The liquid compression molding material according to any one of items 1 to 5 above, wherein component (A) contains an aliphatic epoxy resin.

[0016] 7. The liquid compression molding material according to item 6 above, wherein the aliphatic epoxy resin has a number average molecular weight of 200 to 1,000.

[0017] 8. The liquid compression molding material according to item 6 or 7 above, wherein the aliphatic epoxy resin contains a compound represented by the following general formula (I): [ka] [In the formula, n is an integer of 1 to 15.]

[0018] 9. The liquid compression molding material according to any one of items 1 to 8 above, wherein component (B) contains a phenol compound.

[0019] 10. The liquid compression molding material according to any one of items 1 to 9 above, wherein component (C) contains silica. [Effects of the Invention]

[0020] The liquid compression molding material of the present invention has suitable rheological properties, so that it does not leak from the mold when subjected to compression molding, and can easily and efficiently seal semiconductor elements. [Brief explanation of the drawings]

[0021] [Figure 1] This figure shows the mechanism of leakage of liquid compression molding (LCM) material from a mold when a silicon wafer coated with LCM material is subjected to compression molding. (a) Application of LCM material to a silicon wafer. (b) State of LCM material on a silicon wafer from when it is applied to the silicon wafer until stress is applied to the LCM material and it is stretched. If the TI of the LCM material is less than 0.8 (bottom), the LCM material will naturally spread on the silicon wafer to a position close to the inner surface of the mold. If the TI of the LCM material is appropriate (top), the LCM material will naturally spread on the silicon wafer only to a position relatively far from the inner surface of the mold. (c) State of LCM material on a silicon wafer immediately after stress is applied to the LCM material and it is stretched. If the TI of the LCM material is less than 0.8 (bottom), the stretched LCM material will reach the inner surface of the mold in a very short time, and depending on the mold shape, the LCM material may overflow the mold before it is completely closed. If the TI of the LCM material is appropriate (top row), the time it takes for the stretched LCM material to reach the mold inner surface is longer than that in the previous case, so that the stretched LCM material reaches the mold inner surface only after the mold is completely closed, preventing leakage of the LCM material from the mold. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described in detail. The present invention is a liquid compression molding material comprising the following components (A) to (C): (A) Epoxy resin; (B) a curing agent; and (C) filler; and The present invention relates to a liquid compression molding (LCM) material having a thixotropic index (TI) of 0.8 to 4.0. The components (A) to (C) contained in the LCM material of the present invention will be explained below.

[0023] [Epoxy resin (component (A))] The LCM material of the present invention contains an epoxy resin, which may be referred to hereinafter as "component (A)." Component (A) in the LCM material of the present invention can be an epoxy resin used as a sealing material. The epoxy resin is preferably a multifunctional epoxy resin having two or more functionalities. Examples of multifunctional epoxy resins include monocyclic aromatic epoxy resins such as catechol diglycidyl ether, resorcinol diglycidyl ether, phthalic acid diglycidyl ester, 2,5-diisopropylhydroquinone diglycidyl ether, and hydroquinone diglycidyl ether; alicyclic epoxy resins such as 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexylcarboxylate, bis(3,4-epoxycyclohexyl)adipate, vinylcyclohexene monoepoxide, and diepoxylimonene; bisphenol A type, bisphenol B, and the like. Examples of such epoxy resins include bisphenol-type epoxy resins such as phenol F type, bisphenol AD ​​type, and bisphenol S type; oligomer mixtures obtained by partial polymerization of bisphenol-type epoxy resins; bisphenol-type epoxy resins having hydrogenated rings; tetramethylbis(4-hydroxyphenyl)methane diglycidyl ether; tetramethylbis(4-hydroxyphenyl)ether diglycidyl ether; biphenyl-type or tetramethylbiphenyl-type epoxy resins and resins having hydrogenated rings thereof; fluorene-type epoxy resins such as bisphenolfluorene-type epoxy resins and biscresolfluorene-type epoxy resins; and naphthalene-type epoxy resins.

[0024] Further, examples of polyfunctional epoxy resins include polyfunctional glycidylamine-type epoxy resins such as aminophenol-type epoxy resins such as triglycidyl-p-aminophenol, aniline-type epoxy resins such as diglycidylaniline, toluidine-type epoxy resins such as diglycidyl orthotoluidine, and diaminodiphenylmethane-type epoxy resins such as tetraglycidyldiaminodiphenylmethane; dicyclopentadiene-type epoxy resins; and polyfunctional glycidyl ethers such as trimethylolpropane triglycidyl ether, trimethylolmethane triglycidyl ether, trimethylolethane triglycidyl ether, and other trimethylolalkane-type epoxy resins.

[0025] Other epoxy resins such as aliphatic epoxy resins, silylated epoxy resins, heterocyclic epoxy resins, diallyl bisphenol A type epoxy resins, polyarylene ether diglycidyl ethers, etc. can also be used.

[0026] Among these epoxy resins, examples of aliphatic epoxy resins include difunctional aliphatic epoxy resins having two epoxy groups in the molecule, such as alkylene glycol diglycidyl ether, poly(alkylene glycol) diglycidyl ether, and alkenylene glycol diglycidyl ether; and polyfunctional aliphatic epoxy resins having three or more epoxy groups in the molecule, such as polyglycidyl ethers of trifunctional or higher alcohols (trimethylolpropane, pentaerythritol, dipentaerythritol, etc.) [trimethylolpropane triglycidyl ether, pentaerythritol (tri- or tetra)glycidyl ether, dipentaerythritol (tri-, tetra-, penta-, or hexa-)glycidyl ether, etc.].

[0027] Among these aliphatic epoxy resins, difunctional aliphatic epoxy resins are preferred. Examples of difunctional aliphatic epoxy resins include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,3-propanediol diglycidyl ether, 2-methyl-1,3-propanediol diglycidyl ether, 2-butyl-2-ethyl-1,3-propanediol diglycidyl ether, 1,4-butanediol diglycidyl ether (tetramethylene glycol diglycidyl ether), neopentyl glycol diglycidyl ether, 3-methyl-2,4-pentanediol diglycidyl ether, 2,4-pentanediol diglycidyl ether, 1,5-pentanediol diglycidyl ether (pentamethylene glycol diglycidyl ether), alkylene glycol diglycidyl ethers (alkanediol diglycidyl ethers) such as diglycidyl ether, 3-methyl-1,5-pentanediol diglycidyl ether, 2-methyl-2,4-pentanediol diglycidyl ether, 2,4-diethyl-1,5-pentanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether (hexamethylene glycol diglycidyl ether), 1,7-heptanediol diglycidyl ether, 3,5-heptanediol diglycidyl ether, 1,8-octanediol diglycidyl ether, 2-methyl-1,8-octanediol diglycidyl ether, and 1,9-nonanediol diglycidyl ether;Examples of the diglycidyl ether include polyalkylene glycol diglycidyl ethers (including oligoalkylene glycol diglycidyl ethers) such as diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, tetraethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, poly(ethylene glycol / propylene glycol) diglycidyl ether, ditetramethylene glycol diglycidyl ether, tritetramethylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, dipentamethylene glycol diglycidyl ether, tripentamethylene glycol diglycidyl ether, polypentamethylene glycol diglycidyl ether, dihexamethylene glycol diglycidyl ether, trihexamethylene glycol diglycidyl ether, and polyhexamethylene glycol diglycidyl ether;

[0028] In one embodiment, the difunctional aliphatic epoxy resin is a (poly)alkylene glycol diglycidyl ether, preferably a (poly)alkylene glycol diglycidyl ether having 1 to 20 alkylene glycol (alkyleneoxy) units, and more preferably a (poly)alkylene glycol diglycidyl ether having 1 to 20 alkylene glycol units and having 2 to 4 carbon atoms in the alkylene glycol units. In another embodiment, the difunctional aliphatic epoxy resin is a polyalkylene glycol diglycidyl ether having 2 to 20 alkylene glycol (alkyleneoxy) units, preferably a polyalkylene glycol diglycidyl ether having 2 to 20 alkylene glycol units and having 2 to 4 carbon atoms in the alkylene glycol units.

[0029] The molecular weight of the aliphatic epoxy resin (when the aliphatic epoxy resin is a polymer, the molecular weight is the number average molecular weight in terms of standard polystyrene determined by gel permeation chromatography (GPC) using tetrahydrofuran as an elution solvent) is not particularly limited, but is preferably 200 to 10,000, more preferably 200 to 1,200, even more preferably 200 to 1,000, and particularly preferably 300 to 900.

[0030] A more preferred specific example of the aliphatic epoxy resin is a compound represented by the following general formula (I), that is, a diglycidyl ether of (poly)tetramethylene glycol. [ka] (wherein n is an integer of 1 to 15)

[0031] As the compound represented by general formula (I), commercially available products such as "Epogose PT (general grade)" (Yokkaichi Synthetic Co., Ltd., diglycidyl ether of polytetramethylene glycol, number average molecular weight 700 to 800) may be used.

[0032] In the LCM material of the present invention, a single epoxy resin may be used as component (A), or two or more epoxy resins may be used in combination. In the present invention, it is particularly preferable that component (A) contains an aliphatic epoxy resin, and it is more preferable that the aliphatic epoxy resin contains a compound represented by general formula (I). In addition, it is preferable that the number average molecular weight of the aliphatic epoxy resin is 200 to 1,000.

[0033] [Curing agent (component (B))] The LCM material of the present invention contains a curing agent. There are no particular limitations on the type of curing agent, as long as it is capable of curing the epoxy resin (component (A)). Hereinafter, this curing agent may be referred to as "component (B)."

[0034] Examples of component (B) used in the LCM material of the present invention include imidazole compounds, amine compounds, phenolic compounds, acid anhydrides, etc. Among these, the imidazole compounds may be latent or in the form of a microencapsulated curing agent.

[0035] Examples of the imidazole compound include 2-substituted imidazole compounds such as imidazole, 2-methylimidazole, 2-ethylimidazole, 1-isobutyl-2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, and 1-cyanoethyl-2-phenylimidazole; 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole; trimellitic acid salts such as nylimidazolium trimellitate; triazine ring-containing compounds such as 2,4-diamino-6-[(2-methyl-1-imidazolyl)ethyl]s-triazine, 2,4-diamino-6-[(2-undecyl-1-imidazolyl)ethyl]s-triazine, and 2,4-diamino-6-[(2-ethyl-4-methyl-1-imidazolyl)ethyl]s-triazine; an isocyanuric acid adduct of 2,4-diamino-6-[(2-methyl-1-imidazolyl)ethyl]s-triazine, an isocyanuric acid adduct of 2-phenylimidazole, an isocyanuric acid adduct of 2-methylimidazole, an isocyanuric acid adduct of 2-phenyl-4,5-dihydroxymethylimidazole, and an isocyanuric acid adduct of 2-phenyl-4-methyl-5-hydroxymethylimidazole. Of these imidazole compounds, 2-phenyl-4-methylimidazole, 2,4-diamino-6-[(2-methyl-1-imidazolyl)ethyl]s-triazine, 2-phenyl-4-methyl-5-hydroxymethylimidazole (including its isocyanuric acid adduct), and the like are preferred.

[0036] The microcapsule-type curing agent may be, for example, a dispersion in which an amine compound powder is dispersed in a liquid epoxy resin. The amine compound may be selected from, for example, aliphatic primary amines, alicyclic primary amines, aromatic primary amines, aliphatic secondary amines, alicyclic secondary amines, aromatic secondary amines, imidazole compounds, and imidazoline compounds. The amine compound may be used in the form of a reaction product with a carboxylic acid, sulfonic acid, isocyanate, epoxide, or the like. These compounds may be used alone or in combination of two or more. For example, the amine compound may be used in combination with its reaction product with a carboxylic acid, sulfonic acid, isocyanate, or epoxide. The volume average particle size of the amine compound powder is preferably 30 μm or less, more preferably 5 μm or less. Furthermore, the amine compound powder preferably has a melting point or softening point of 60°C or higher in order to suppress viscosity increase at 25°C.

[0037] As the phenolic compound, phenolic resins, particularly novolak resins obtained by condensing phenols or naphthols (e.g., phenol, cresol, naphthol, alkylphenols, bisphenols, terpene phenols, etc.) with formaldehyde, are preferred. Examples of novolak resins include phenol novolak resins, o-cresol novolak resins, p-cresol novolak resins, α-naphthol novolak resins, β-naphthol novolak resins, t-butylphenol novolak resins, bisphenol A novolak resins, xylylene-modified novolak resins, and decalin-modified novolak resins. Other examples of phenolic resins include dicyclopentadiene cresol resins, poly(p-vinylphenol), poly(di-o-hydroxyphenyl)methane, poly(di-m-hydroxyphenyl)methane, and poly(di-p-hydroxyphenyl)methane.

[0038] Examples of the acid anhydride include phthalic anhydride, hexahydrophthalic anhydride, alkylhexahydrophthalic anhydrides such as methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, alkyltetrahydrophthalic anhydrides such as trialkyltetrahydrophthalic anhydride and 3-methyltetrahydrophthalic anhydride, himic anhydride, succinic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. Of these, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, etc. are preferred.

[0039] Examples of the amine compound include tetramethyldiaminodiphenylmethane, tetraethyldiaminodiphenylmethane, diethyldimethyldiaminodiphenylmethane, dimethyldiaminotoluene, diaminodibutyltoluene, diaminodipropyltoluene, diaminodiphenylsulfone, diaminoditolylsulfone, diethyldiaminotoluene, bis(4-amino-3-ethylphenyl)methane, polytetramethylene oxide-di-p-aminobenzoate, etc. Among these, bis(4-amino-3-ethylphenyl)methane, etc. is preferred. Further examples of the amine compound include 2,4,6-tris(dimethylaminomethyl)phenol, diethylamine, triethylamine, diethylenetetramine, triethylenetetramine, and 4,4-dimethylaminopyridine. The amine compound may be an amine adduct.

[0040] In the LCM material of the present invention, a single curing agent may be used as component (B), or two or more curing agents may be used in combination. In the present invention, component (B) preferably contains an imidazole compound, and more preferably contains both an imidazole compound and a phenolic compound (preferably in liquid form).

[0041] The LCM material of the present invention preferably contains 1 to 20% by weight, more preferably 2 to 15% by weight, and particularly preferably 3 to 10% by weight of component (B) relative to 100 parts by weight of component (A).

[0042] [Filler (Component (C))] The LCM material of the present invention contains a filler, which may be referred to hereinafter as "component (C)." Examples of the filler of component (C) used in the present invention include, but are not limited to, silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, boron nitride (BN), glass beads, etc. In the present invention, it is preferable that component (C) contains silica. This is because silica also functions as a rheology modifier. The silica may be natural silica (such as silica stone or quartz) or synthetic silica. Synthetic silica can be synthesized by any method, including dry and wet methods. Component (C) may also be surface-treated with a surface treatment agent, for example, a coupling agent such as a silane coupling agent (which may have a substituent such as a phenyl group, a vinyl group, or a methacryloyl group). In the present invention, it is preferred that at least a portion of component (C) is surface-treated.

[0043] In one embodiment, component (C) comprises silica powder, which is commercially available. In the present invention, it is more preferable that component (C) contains fused silica powder and / or silica powder produced by a deflagration method. The deflagration method is a method for producing a silica powder consisting of fine spherical silica particles by oxidizing metal silicon powder dispersed in an oxygen stream by ignition, melting or vaporizing the resulting oxide (which may contain unreacted metal silicon) by heating using the heat of the oxidation reaction, and then cooling to a temperature below the melting point of the oxide. Examples of fused silica powder include those consisting of spherical silica particles and those consisting of crushed silica particles. From the viewpoint of the flowability of the LCM material, it is more preferable that component (C) contains silica powder consisting of spherical silica particles (especially those with high sphericity).

[0044] In the LCM material of the present invention, a single filler may be used as component (C), or two or more fillers may be used in combination. When component (C) contains two or more fillers, the fillers may differ in the material contained in the particles that make them up, or when the fillers are composed of particles containing the same material, the fillers may differ in their manufacturing method or some other characteristic (e.g., particle size distribution, as described below). In one embodiment, component (C) contains two or more fillers.

[0045] The properties of the particles constituting component (C), such as particle size distribution, are not particularly limited. However, from the viewpoint of an appropriate thixotropic index (described later) of the LCM material, in the present invention, component (C) preferably contains particles having a particle size of 5 nm to 100 nm, more preferably particles having a particle size of 10 nm to 50 nm, in an amount of 5 to 23 wt %, and more preferably 8 to 19 wt %, based on the total weight of component (C). In this case, the properties of particles other than those having a particle size of 5 nm to 100 nm in component (C) are not particularly limited, except for the content in component (C). The particle size distribution of the particles constituting component (C) can be obtained by analyzing a micrograph (e.g., an electron micrograph) taken of a sample of component (C) using image processing software, and quantifying and statistically processing the sizes of all or some of the particles in the micrograph. Here, when component (C) contains two or more fillers, the particle size distribution of the particles constituting component (C) refers to the particle size distribution of the particles constituting component (C) as a mixture of all of those fillers. The particles in component (C) having a particle size of 5 nm to 100 nm are preferably surface-treated.

[0046] The LCM material of the present invention preferably contains 65 to 90 wt %, more preferably 68 to 88 wt %, and particularly preferably 70 to 85 wt % of component (C) relative to the total weight of the LCM material.

[0047] The LCM material of the present invention has a thixotropic index (TI) of 0.8 to 4.0. The TI is preferably 0.8 to 2.0. In the present invention, the TI of the LCM material is determined by the following formula: TI=η1 / η 10 (In the formula, η1 is the viscosity of the LCM material measured using a rotational viscometer at a temperature of 25°C and a rotation speed of 1 ppm. η 10 is the viscosity of the LCM material measured under the same conditions as η1 except that the rotation speed was 10 ppm. It is expressed as:

[0048] As mentioned above, when conventional LCM materials are subjected to a encapsulation process by compression molding, they may leak from the mold seams, which means that the rheological properties of conventional LCM materials are not suitable for such an encapsulation process. As a result of various investigations, the present inventors have found that a specific epoxy resin composition having a TI of 0.8 to 4.0 exhibits rheological properties suitable for encapsulation treatment by compression molding, and is useful as an LCM material. If the TI of the LCM material is less than 0.8, the LCM material will leak from the mold during compression molding, whereas if the TI of the LCM material is greater than 4.0, it will be difficult to eject the LCM material from the application means.

[0049] In the encapsulation process using compression molding, it takes a certain amount of time for the LCM material to be applied to the encapsulated object after it is applied. During this time, the applied LCM material naturally spreads over the encapsulated object to a certain extent. If the TI of the LCM material is less than 0.8, the LCM material will spread to a position close to the inner surface of the mold. Therefore, when the LCM material is stretched by the applied stress, it reaches the inner surface of the mold in a very short time. Depending on the shape of the mold, the LCM material may overflow from the mold before it is completely closed.

[0050] On the other hand, when the TI of an LCM material is within the above range, the LCM material naturally spreads on the object to be sealed only to a position relatively far from the inner surface of the mold after being applied to the object to be sealed and before stress is applied. Therefore, the time required for such an LCM material stretched by the applied stress to reach the inner surface of the mold is longer than the time required for an LCM material with a TI of less than 0.8. As a result, the stretched LCM material reaches the inner surface of the mold after the mold is completely closed, preventing leakage of the LCM material from the mold. The above was discovered for the first time by the present inventors.

[0051] According to the above definition of TI, when the TI of an LCM material is 1 or less, the viscosity of the LCM material under relatively high shear stress is the same as or higher than the viscosity of the LCM material under relatively low shear stress. However, because the viscosity of an LCM material varies depending on the measurement conditions, the behavior of an LCM material under actual compression molding conditions may not match the behavior predicted from the TI defined above.

[0052] One example of a method for achieving such suitable rheological properties, i.e., suitable TI, of an LCM material is to appropriately adjust the particle size distribution of component (C) to include fine particles with particle sizes of 5 to 100 nm (e.g., 5 to 23 wt % of the total weight of component (C)), as described above. This method is particularly useful when component (C) contains silica, since silica also functions as a rheology modifier.

[0053] An epoxy resin composition used as an encapsulant for semiconductors, prepared using a filler containing the above-mentioned fine particles, is disclosed, for example, in Patent Document 2. However, this epoxy resin composition is intended for use as an underfill agent, and the underfill agent must have higher fluidity (evaluated, for example, as the "viscosity at 120°C" described below) than an LCM material. For this reason, it is not preferable for this epoxy resin composition to have a high fine particle content in the filler (for example, more than 20 wt % relative to the total weight of the filler).

[0054] In the present invention, the viscosity of the LCM material at 25°C is preferably 10 to 1000 Pa·s, more preferably 30 to 900 Pa·s, and even more preferably 50 to 800 Pa·s. In the present invention, the viscosity of the LCM material at 25°C is determined by the above η 10 It is measured in the same manner as the measurement of

[0055] Furthermore, the viscosity of the LCM material of the present invention at 120°C is preferably 0.3 to 6.0 Pa·s, more preferably 0.5 to 5.5 Pa·s, and even more preferably 0.8 to 5.1 Pa·s. In the present invention, the viscosity at 120°C refers to the viscosity (unit: Pa·s) measured at 120°C after applying a 10 Hz vibration at 120°C for 1 minute under conditions in which the shear strain is controlled to a constant value using a rheometer. In contrast, the viscosity of underfill agents at 120°C is usually less than 0.3 Pa·s.

[0056] If desired, the LCM material of the present invention may contain optional components such as those described below, in addition to the above-mentioned components (A) to (C), which are essential components.

[0057] Curing accelerator The LCM material of the present invention may contain a curing accelerator if desired. The curing accelerator used in the present invention is not particularly limited as long as it is a compound that can accelerate the curing of the epoxy resin (component (A)) by the curing agent (component (B)), and known compounds can be used. Examples of curing accelerators include basic compounds such as amine compounds, phosphorus compounds, and organometallic compounds. Examples of the amine compound also include 2,4,6-tris(dimethylaminomethyl)phenol, diethylamine, triethylamine, diethylenetetramine, triethylenetetramine, and 4,4-dimethylaminopyridine. The amine compound may be an amine adduct.

[0058] Examples of the phosphorus compound include trialkylphosphine compounds such as tributylphosphine, and triarylphosphine compounds such as triphenylphosphine.

[0059] Examples of the organometallic compound include zinc naphthenate, cobalt naphthenate, tin octoate, cobalt octoate, bisacetylacetonate cobalt(II), and trisacetylacetonate cobalt(III).

[0060] When the LCM material of the present invention contains a curing accelerator, the amount of the curing accelerator is preferably 1 to 100 parts by weight, and more preferably 5 to 50 parts by weight, per 100 parts by weight of the total amount of components (A) to (C).

[0061] Pigments The LCM material of the present invention may contain a pigment, if desired. The inclusion of a pigment allows for the adjustment of the chromaticity of the LCM material of the present invention. Furthermore, considering the possibility that wiring within electronic components may be affected by light, the use of a pigment is important. Pigments are not particularly limited, but examples include carbon black, titanium black (e.g., titanium nitride), black organic pigments, mixed-color organic pigments, and inorganic pigments. Examples of black organic pigments include perylene black and aniline black. Examples of mixed-color organic pigments include pseudo-black pigments obtained by mixing at least two pigments selected from red, blue, green, purple, yellow, magenta, cyan, etc. Examples of inorganic pigments include graphite, and fine particles of metals and their oxides (including composite oxides), sulfides, nitrides, etc. Examples of metals include titanium, copper, iron, manganese, cobalt, chromium, nickel, zinc, calcium, silver, etc. In the LCM material of the present invention, a pigment may be used alone or in combination with two or more pigments. Furthermore, a pigment may be used in combination with other colorants such as dyes.

[0062] From the viewpoint of heat resistance, the pigment is preferably carbon black.

[0063] Stabilizers The LCM material of the present invention may contain a stabilizer, if desired, to improve its storage stability and extend its pot life. Various stabilizers known as stabilizers for one-component adhesives based on epoxy resins can be used, but at least one selected from the group consisting of liquid borate ester compounds, aluminum chelates, and organic acids is preferred due to its high effectiveness in improving storage stability.

[0064] Examples of liquid boric acid ester compounds include 2,2'-oxybis(5,5'-dimethyl-1,3,2-oxaborinane), trimethyl borate, triethyl borate, tri-n-propyl borate, triisopropyl borate, tri-n-butyl borate, tripentyl borate, triallyl borate, trihexyl borate, tricyclohexyl borate, trioctyl borate, trinonyl borate, tridecyl borate, tridodecyl borate, trihexadecyl borate, trioctadecyl borate, tris(2-ethylhexyloxy)borane, bis(1,4,7,10-tetraoxaundecyl)(1,4,7,10,13-pentaoxatetradecyl)(1,4,7-trioxaundecyl)borane, tribenzyl borate, triphenyl borate, tri-o-tolyl borate, tri-m-tolyl borate, and triethanolamine borate. Liquid boric acid ester compounds are preferred because they are liquid at room temperature (25°C), which allows the viscosity of the LCM material to be kept low. For example, aluminum chelate A can be used as the aluminum chelate. For example, barbituric acid can be used as the organic acid.

[0065] When the LCM material of the present invention contains a stabilizer, the amount of the stabilizer is preferably 0.01 to 30 parts by weight, more preferably 0.05 to 25 parts by weight, and even more preferably 0.1 to 20 parts by weight, per 100 parts by weight of component (A).

[0066] Silicone additives The LCM material of the present invention may contain a silicone-based additive if desired. The inclusion of a silicone-based additive is preferred from the viewpoint of improving the fluidity of the LCM material. The silicone-based additive is preferably a dialkylpolysiloxane (the alkyl group bonded to Si includes methyl, ethyl, etc.), particularly dimethylpolysiloxane. The silicone-based additive may also be a modified dialkylpolysiloxane, for example, an epoxy-modified dimethylpolysiloxane. Specific examples of silicone-based additives include KF69 (dimethyl silicone oil, manufactured by Shin-Etsu Silicone Co., Ltd.) and SF8421 (epoxy-modified silicone oil, manufactured by Toray Dow Silicone Co., Ltd.). The silicone-based additives may be used alone or in combination of two or more.

[0067] When the LCM material of the present invention contains a silicone additive, the amount of the silicone additive is preferably 0.1 to 1.0 parts by weight, more preferably 0.25 to 1 part by weight, per 100 parts by weight of component (A).

[0068] Coupling agents The LCM material of the present invention may contain a coupling agent if desired. The inclusion of a coupling agent, particularly a silane coupling agent, is preferred from the viewpoint of improving adhesive strength. As the coupling agent, various silane coupling agents such as epoxy-based, amino-based, vinyl-based, methacrylic-based, acrylic-based, and mercapto-based silane coupling agents can be used. Specific examples of silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, vinyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatepropyltriethoxysilane, etc. These silane coupling agents may be used alone or in combination of two or more.

[0069] When the LCM material of the present invention contains a coupling agent, the amount of the coupling agent is preferably 0.01 to 5 parts by weight, and more preferably 0.1 to 5 parts by weight, per 100 parts by weight of component (A).

[0070] Migration inhibitor The LCM material of the present invention may contain a migration inhibitor, if desired. Migration is a phenomenon in which metal in a wiring pattern is eluted due to an electrochemical reaction, resulting in a decrease in resistance. The inclusion of a migration inhibitor is preferable from the viewpoint of improving the reliability of electronic components. Specific examples of migration inhibitors include xanthines such as caffeine, theophylline, theobromine, and paraxanthine; tocols such as 5,7,8-trimethyltocol (α-tocopherol), 5,8-dimethyltocol (β-tocopherol), 7,8-dimethyltocol (γ-tocopherol), and 8-methyltocol (δ-tocopherol); 5,7,8-trimethyltocotrienol (α-tocotrienol), 5,8-dimethyltocotrienol (β-tocotrienol), and 7,8-dimethyltocotrienol (γ-tocotrienol). tocotrienols such as 8-methyltocotrienol (δ-tocotrienol); benzotriazoles such as benzotriazole, 1H-benzotriazole-1-methanol, and alkylbenzotriazoles; triazines such as 2,4-diamino-6-vinyl-S-triazine, 2,4-diamino-6-[2'-ethyl-4-methylimidazole-(1)]-ethyl-S-triazine, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine; and isocyanuric acid adducts of the above benzotriazoles or triazines. These migration inhibitors may be used alone or in combination of two or more.

[0071] When the LCM material of the present invention contains a migration inhibitor, the amount of the migration inhibitor is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 5 parts by weight, per 100 parts by weight of component (A).

[0072] Other additives If desired, the LCM material of the present invention may contain other additives, such as an ion trapping agent, a leveling agent, an antioxidant, an antifoaming agent, a thixotropic agent, a viscosity modifier, a flame retardant, a solvent, etc. The type and amount of each additive are as per usual, provided that the addition does not impair the spirit of the present invention.

[0073] The method for producing the liquid compression molding (LCM) material of the present invention is not particularly limited. For example, the LCM material of the present invention can be obtained by introducing components (A) to (C) and, if desired, other additives into an appropriate mixer simultaneously or separately, and mixing them by stirring while melting them by heating if necessary, to form a uniform composition. The mixer is not particularly limited, and examples that can be used include a Raikai mixer equipped with a stirrer and a heater, a Henschel mixer, a three-roll mill, a ball mill, a planetary mixer, and a bead mill. These devices may also be used in appropriate combinations.

[0074] In the LCM material of the present invention, when component (C) contains particles having a particle size of 5 nm to 100 nm (for example, 5 to 23 wt % relative to the total weight of component (C)), the LCM material of the present invention is preferably obtained by a method including a step of pre-mixing at least a portion of the particles having a particle size of 5 nm to 100 nm in component (C) with at least a portion of component (A). The LCM material of the present invention can preferably be obtained by the above-mentioned method.

[0075] The liquid compression molding material thus obtained is thermosetting, and at a temperature of 100 to 170°C, it cures preferably in 0.1 to 3 hours, and more preferably in 0.25 to 2 hours.

[0076] The liquid compression molding material of the present invention is suitable for the production of electronic components, particularly semiconductor devices that require encapsulation by compression molding. More specifically, the liquid compression molding material of the present invention is particularly useful for encapsulating wafers on which circuit formation has been completed but which have not yet been cut into chips, when manufacturing semiconductor devices with miniaturized packages using wafer-level chip size packaging.

[0077] The present invention also provides a cured product obtained by curing the LCM material of the present invention, and an electronic component comprising the cured product of the present invention. [Example]

[0078] The present invention will be described below with reference to examples, but is not limited to these. In the following description, parts and % refer to parts by weight and % by weight unless otherwise specified.

[0079] Examples 1 to 17, Comparative Examples 1 to 5 Liquid compression molding (LCM) materials were prepared by mixing the specified amounts of each component using a three-roll mill according to the formulation shown in Table 1. In Table 1, the amount of each component is expressed by weight (unit: g).

[0080] Epoxy resin (component (A)) In the examples and comparative examples, the compounds used as component (A) are as follows. (A-1): Diglycidyl ether of polytetramethylene glycol (number average molecular weight 700 to 1000) (trade name: Epogosey PT (general grade), manufactured by Yokkaichi Synthetic Co., Ltd.) (A-2): Aminophenol-type epoxy resin (product name: 630, manufactured by Mitsubishi Chemical Corporation)

[0081] Hardener (component (B)) In the examples and comparative examples, the compounds used as component (B) are as follows. (B-1): Imidazole compound (trade name: Curesol 2P4MZ, manufactured by Shikoku Chemicals Corporation) (B-2): Imidazole compound (trade name: Curesol 2MZ-A, manufactured by Shikoku Chemicals Corporation) (B-3): Imidazole compound (trade name: Curesol 2P4MHZ-PW, manufactured by Shikoku Chemicals Corporation) (B-4): Liquid phenol novolac resin (product name: MEH-8005, manufactured by Meiwa Kasei Co., Ltd.) (B-5): Amine compound (trade name: Kayahard AA, Nippon Kayaku Co., Ltd.) (B-6): Acid anhydride (trade name: HN-5500, Hitachi Chemical Co., Ltd.)

[0082] Filler (component (C)) The compounds used as component (C) in the examples and comparative examples are as follows: These compounds are divided into two groups: those with an average particle size of more than 0.1 μm (100 nm) and those with an average particle size of 0.1 μm (100 nm) or less.

[0083] <Filler with an average particle size exceeding 0.1 μm (100 nm)> (C-1): Silica filler (product name: SO-E2, manufactured by Admatechs Co., Ltd., average particle size: 0.6 μm) (C-2): Silica filler (product name: SO-E5, manufactured by Admatechs Co., Ltd., average particle size: 1.5 μm) (C-3): Silica filler (product name: SO-E6, manufactured by Admatechs Co., Ltd., average particle size: 2 μm)

[0084] <Filler with an average particle size of 0.1 μm (100 nm) or less> (C-4): Silica filler (product name: Aerosil (registered trademark) R805, manufactured by Toshin Kasei Co., Ltd., average particle size: 7 nm, surface treated with octylsilane) (C-5): Silica filler (product name: YA010C, manufactured by Admatechs Co., Ltd., average particle size: 10 nm, surface treated) (C-6): Silica filler (product name: YA050C, manufactured by Admatechs Co., Ltd., average particle size: 50 nm, surface treated) (C-7): Silica filler (product name: YC100C, manufactured by Admatechs Co., Ltd., average particle size: 100 nm, surface treated)

[0085] In the examples and comparative examples, the properties of the LCM materials were measured as follows.

[0086] (Viscosity of LCM material at 25°C) The viscosity (unit: Pa·s) of the manufactured LCM material was measured at 25°C and 10 revolutions per minute using a Brookfield HB-type rotational viscometer (spindle SC4-14). The results are shown in Table 1.

[0087] (Viscosity of LCM material at 120℃) Using a HAAKE MARS rheometer, the manufactured LCM material was subjected to vibration at a frequency of 10 Hz for 1 minute at 120°C in the oscillation strain control mode, and then the viscosity (unit: Pa s) was measured at 120°C. The results are shown in Table 1.

[0088] (Thixotropic index (TI) of LCM material) The viscosity (unit: Pa·s) of the manufactured LCM material was measured under the same conditions as the "Viscosity of LCM material at 25°C" above, except that the rotation speed was 1 rotation / minute. The thixotropic index (TI) of the LCM material was calculated by dividing the "Viscosity of LCM material at 25°C" above by this viscosity. The results are shown in Table 1.

[0089] (Evaluation of formability of LCM material) An amount of the LCM material produced, equivalent to the volume of a 292 mm diameter, 400 μm thick disk, was applied to a silicon wafer (300 mm diameter, 780 μm thick disk). This silicon wafer was placed in a mold attached to a compression molding machine WCM300 (manufactured by Apic Yamada) and subjected to compression molding (sealing) at a temperature of 120°C and a pressure of 350 kN. The LCM material was visually monitored for leakage from the mold during compression molding. If leakage occurred, the moldability of the LCM material was rated as "x", and if no leakage occurred, the moldability of the LCM material was rated as "good". If it was not possible to evaluate the moldability using the above method, the moldability of the LCM material was also rated as "x".

[0090] (Evaluation of the fluidity of LCM materials) 40 g of the produced LCM material was loaded into a dispensing device ML-5000XII (Musashi Engineering) equipped with a nozzle with an inner diameter of 10 mm, and discharged from the device at a discharge pressure of 0.2 MPa. If the loaded LCM material was completely discharged within 5 minutes, the fluidity of the LCM material was evaluated as "Good," and if it took more than 5 minutes for the loaded LCM material to be completely discharged, the fluidity of the LCM material was evaluated as "Poor." In addition, if it was impossible to evaluate the fluidity using the above method, the fluidity of the LCM material was also evaluated as "Poor."

[0091] [Table 1-1] [Table 1-2] [Table 1-3]

[0092] As is clear from Table 1, in all of Examples 1 to 17, in which the thixotropic index (TI) of the LCM material was 0.8 to 4.0, the LCM material exhibited appropriate fluidity that allowed it to be easily discharged from a dispensing device, and also had good moldability, and no leakage of the LCM material from the mold was observed when subjected to compression molding together with a silicon wafer. In contrast, in Comparative Examples 1, 3, and 5, in which the TI of the LCM material was less than 0.8, the moldability was insufficient, and when the LCM material was subjected to compression molding together with a silicon wafer, leakage of the LCM material from the mold was observed. Furthermore, in Comparative Examples 2 and 4, the LCM material was almost solid, making it impossible to measure viscosity or evaluate moldability and flowability. [Industrial Applicability]

[0093] The LCM material of the present invention has suitable rheological properties. Therefore, even when the LCM material of the present invention is subjected to compression molding, leakage from the mold does not occur, and semiconductor devices can be easily and efficiently encapsulated by compression molding. Therefore, the LCM material of the present invention is useful in the manufacture of semiconductor devices that involve encapsulation by compression molding, particularly in the manufacture of semiconductor devices in miniaturized packages using wafer-level chip size packaging. [Explanation of symbols]

[0094] 1 Liquid Compression Molding (LCM) Materials 2 silicon wafers 3 Upper mold 4 Lower mold

Claims

1. A liquid compression molding material comprising the following components (A) to (C): (A) epoxy resin; (B) a curing agent; and (C) Filler and A liquid compression molding material having a thixotropic index (TI) of 0.8 to 4.

0.

2. 2. The liquid compression molding material according to claim 1, wherein component (C) contains particles having a particle size of 5 nm to 100 nm in an amount of 5 to 23 wt. % based on the total weight of component (C).

3. The liquid compression molding material according to claim 2, which can be obtained by a method including a step of pre-mixing at least a portion of the particles having a particle size of 5 nm to 100 nm in component (C) with at least a portion of component (A).

4. The liquid compression molding material according to any one of claims 1 to 3, wherein component (C) is surface-treated with a coupling agent.

5. The liquid compression molding material according to any one of claims 1 to 4, having a viscosity of 10 to 1000 Pa s at 25 ° C.

6. The liquid compression molding material according to any one of claims 1 to 5, wherein component (A) comprises an aliphatic epoxy resin.

7. The liquid compression molding material according to claim 6, wherein the aliphatic epoxy resin has a number average molecular weight of 200 to 1,000.

8. 8. The liquid compression molding material according to claim 6, wherein the aliphatic epoxy resin contains a compound represented by the following general formula (I): 【Chemistry 3】 [In the formula, n is an integer from 1 to 15.]

9. The liquid compression molding material according to any one of claims 1 to 8, wherein component (B) comprises a phenol compound.

10. The liquid compression molding material according to any one of claims 1 to 9, wherein component (C) comprises silica.

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