JP4786964B2 - Thermosetting epoxy resin composition and semiconductor device using the same - Google Patents

Description

  In particular, the present invention can be applied while maintaining the shape of the outer periphery of a gap between a semiconductor component having a protruding electrode such as a solder bump and an electronic circuit board on which the semiconductor component is mounted, and has excellent drop test and repairability. The present invention relates to a liquid epoxy resin composition for providing a stopper and a semiconductor device sealed with this sealing material.

  Along with the downsizing, weight reduction, and higher functionality of electrical equipment, semiconductor mounting methods have become mainstream from pin insertion type to surface mounting. Recently, with the increase in the number of pins of a package, a ball grid array (BGA) type semiconductor device has been widely used. After such a package is connected to an electronic circuit board, connection failure often becomes a problem due to stress due to a drop test or a thermal shock test. Therefore, conventionally, a prescription for improving connection reliability by injecting an underfill material or the like into a gap between a semiconductor device and an electronic circuit board and curing it has been taken (Japanese Patent Laid-Open No. 10-20259).

In recent years, with the lead-free solder bumps, the need for underfill materials has become increasingly important.
However, if a thermosetting resin type underfill material is used after injecting the underfill material, heat curing at a high temperature of 150 ° C./10 minutes or more is required. Recently, an underfill material having a low temperature of 80 ° C./10 minutes has also been introduced (Japanese Patent Laid-Open No. 2003-246828), which requires a step of injecting a resin and a step of curing the resin, causing a significant decrease in productivity. This is the current situation.
In addition, when a defective electronic component is once mounted, it is essential to repair the electronic component. JP-A-2003-246828 is said that it can be removed at a relatively low temperature of 180 ° C to 250 ° C. Yes.

  However, in practice, this method has a problem that a thin resin film is deposited on the electronic circuit board side and around the solder bumps, and the process of cleaning the resin film is inferior in workability and significantly reduces productivity.

  Furthermore, in Japanese Patent Laid-Open No. 2003-246828, a dam is used so that an underfill material is not filled in a mounting substrate on which high-frequency signal processing is performed for a semiconductor device such as a mobile phone, and a process of using a dam material separately is also remarkable. The cost is raised.

JP-A-10-204259 JP 2003-246828 A

  The present invention has been made in view of the above circumstances, and can be applied while maintaining the shape on the outer periphery of the surface mount semiconductor component solder bump or the outer periphery of the electrode to which the solder bump of the electric circuit board on which the surface mount semiconductor component is mounted is connected. In addition, it can be cured at the same time as solder connection during surface mounting and can be repaired even after curing. In terms of reliability, it maintains the connectivity between the semiconductor device and the electric circuit board even in drop tests and thermal shock tests, and peels off. An object of the present invention is to provide a semiconductor device surface mounting adhesive using a thermosetting epoxy resin composition that does not cause cracks, and a semiconductor device sealed with the cured product.

  As a result of intensive studies to achieve the above object, the present inventor has at least 1 minute or more of a molten state that does not harden at the melting point of the solder bump material when mounting the surface mount semiconductor component on the substrate, It is not injected into the outer periphery of the surface mount semiconductor component solder bump or the entire electrode to which the solder bump of the electric circuit board on which the surface mount semiconductor component is mounted, and can be applied while maintaining the shape on the outer periphery. A thermosetting epoxy resin composition capable of thermosetting, comprising (A) a liquid epoxy resin, (B) a curing agent, (C) a curing accelerator, (D) an inorganic filler, and (E) an epoxy resin or a phenol resin. And a composition containing a silicone-modified resin which is a copolymer of organopolysiloxane and the cured product has a glass transition temperature (Tg) of 30 to 1. A liquid epoxy resin composition having a range of 0 ° C. and a ratio of dynamic viscoelasticity of 30 ° C. or lower to dynamic viscoelasticity of 150 ° C. or higher being 100 or higher is effective as an adhesive for surface mounting of semiconductor devices It has been found that the present invention has been made.

  The liquid epoxy resin composition of the present invention gives a cured product excellent in adhesion to the surface of a silicon chip, particularly a photosensitive polyimide resin or a nitride film, and further in heat resistance and thermal shock resistance. Since the stress is small, the warp of the semiconductor device is reduced, and it is particularly effective as a sealing material for a semiconductor device having a large die size or substrate size. In addition, a semiconductor device using this sealing material is very reliable.

Hereinafter, the present invention will be described in more detail.
[(A) Liquid epoxy resin]
(I) General liquid epoxy resin As long as the liquid epoxy resin of component (A) used in the present invention has two or more epoxy groups in one molecule, the molecular structure, molecular weight and the like are not particularly limited. In particular, bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, novolac type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, cyclopentadiene Type epoxy resin and the like. These epoxy resins can be used individually by 1 type or in mixture of 2 or more types. Among these, a liquid epoxy resin is desirable at room temperature (for example, 25 ° C.).

    Moreover, the epoxy resin of this invention may contain the epoxy resin shown by the following structure in the range which does not affect intrusion property.

本発明においては、特に下記一般式（２）で示されるエポキシ樹脂を含むことが好ましい。

In the present invention, it is particularly preferable to include an epoxy resin represented by the following general formula (2).

ここで、Ｒ¹は水素原子、又は炭素数１〜２０、好ましくは１〜１０、更に好ましくは１〜３の一価炭化水素基であり、一価炭化水素基としては、メチル基、エチル基、プロピル基等のアルキル基、ビニル基、アリル基等のアルケニル基等が挙げられる。また、ｎは１〜４の整数、特に１又は２である。

Here, R ¹ is a hydrogen atom, or a monovalent hydrocarbon group having 1 to 20, preferably 1 to 10, and more preferably 1 to 3 carbon atoms, and examples of the monovalent hydrocarbon group include a methyl group and an ethyl group. And alkyl groups such as propyl group, alkenyl groups such as vinyl group and allyl group. N is an integer of 1 to 4, particularly 1 or 2.

In addition, it is recommended that the content of the epoxy resin of the above formula (2) is 25 to 100% by weight, more preferably 50 to 100% by weight, and further preferably 75 to 100% by weight in the total epoxy resin. If it is less than 25% by weight, the viscosity of the composition may increase or the heat resistance of the cured product may decrease. The viscosity of the epoxy resin as component (A) is preferably 1000 Ps · a or less, preferably 500 Ps · a or less at 25 ° C. from the viewpoint of workability.
Examples of the epoxy resin represented by the general formula (2) include MRGE manufactured by Nippon Kayaku Co., Ltd.

(Ii) Silicone-modified epoxy resin The composition of the present invention includes an alkenyl group of an alkenyl group-containing epoxy resin or an alkenyl group-containing phenol resin, and the following average composition formula (2):
H _a R _b SiO _{(4-ab) / 2} (2)
(In the formula, R is a substituted or unsubstituted monovalent hydrocarbon group, a is 0.01 to 0.1, b is 1.8 to 2.2, and 1.81 ≦ a + b ≦ 2.3.)
The number of silicon atoms in one molecule represented by is from 20 to 400, and the number of hydrogen atoms (SiH groups) directly bonded to the silicon atom is from 1 to 5, preferably from 2 to 4, particularly two. A silicone epoxy-modified resin made of a copolymer obtained by addition reaction with the SiH group of organopolysiloxane is blended.

  As the monovalent hydrocarbon group of R in the above formula, those having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms are preferable, and methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group. Group, hexyl group, octyl group, alkyl group such as decyl group, vinyl group, allyl group, propenyl group, butenyl group, alkenyl group such as hexenyl group, phenyl group, xylyl group, aryl group such as tolyl group, benzyl group, Aralkyl groups such as phenylethyl group, phenylpropyl group, etc., and chloromethyl group, bromoethyl group, trifluoropropyl group in which some or all of hydrogen atoms of these hydrocarbon groups are substituted with halogen atoms such as chlorine, fluorine, bromine, etc. And halogen-substituted monovalent hydrocarbon groups such as a group.

  The copolymer preferably has a structure represented by the general formula.

（式中、Ｒ¹⁰は前記Ｒと同じであり、Ｒ¹¹は炭素数１〜４のアルキル基、Ｒ¹²は−ＣＨ₂ＣＨ₂ＣＨ₂−、−ＯＣＨ₂−ＣＨ（ＯＨ）−ＣＨ₂−Ｏ−ＣＨ₂ＣＨ₂ＣＨ₂−又は−Ｏ−ＣＨ₂ＣＨ₂ＣＨ₂−である。ｍは４〜１９９の整数、ｐは１〜１０の整数、ｑは１〜１０の整数である。）
Ｒ¹⁰としては、炭素数１〜１０、好ましくは炭素数１〜８程度の非置換又はハロゲン置換１価炭化水素基であることが好ましく、具体的には、前記したＲにおいて例示したものと同様のものが挙げられる。また、ｍは１９〜９９の整数であることが好ましい。

(Wherein R ¹⁰ is the same as R, R ¹¹ is an alkyl group having 1 to 4 carbon atoms, and R ¹² is —CH ₂ CH ₂ CH ₂ —, —OCH ₂ —CH (OH) —CH ₂ —). O—CH ₂ CH ₂ CH ₂ — or —O—CH ₂ CH ₂ CH ₂ —, m is an integer of 4 to 199, p is an integer of 1 to 10, and q is an integer of 1 to 10.)
R ¹⁰ is preferably an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably about 1 to 8 carbon atoms, and specifically, the same as those exemplified for R above Can be mentioned. Moreover, it is preferable that m is an integer of 19-99.

  The silicone-modified epoxy resin of the present invention contains 1 to 20 parts by weight, particularly 2 to 15 parts by weight of the diorganosiloxane unit in the copolymer with respect to 100 parts by weight of the liquid epoxy resin of component (A). It is preferable to mix them, whereby the stress can be further reduced and the adhesion is also improved.

  The total chlorine content in the epoxy resin of the present invention is desirably 1500 ppm or less, particularly 1000 ppm or less. Moreover, it is preferable that the extraction water chlorine in 20 hours in the 50% epoxy resin density | concentration at 100 degreeC is 10 ppm or less. If the total chlorine content exceeds 1500 ppm and the extracted water chlorine exceeds 10 ppm, the reliability of the semiconductor element, particularly the moisture resistance, may be adversely affected.

[(B) Curing agent]
A curing agent is added to the liquid epoxy resin composition of the present invention in order to cure the liquid epoxy resin.
The curing agent of the present invention is not particularly limited as long as it can cure the above epoxy resin, and all curing agents used in curable epoxy resin compositions can be used. For example, in a liquid epoxy resin A compound having two or more functional groups (for example, phenolic hydroxyl group, amino group, acid anhydride group, etc.) capable of reacting with the epoxy group of the above (however, one or more acid anhydride groups), molecular structure, molecular weight Etc. are not particularly limited, and publicly known ones can be used, but a phenolic curing agent is particularly preferably used.

  Specific examples of the phenol resin having at least two phenolic hydroxyl groups in one molecule include novolak type phenol resins such as phenol novolak resin and cresol novolak resin, paraxylylene modified novolak resin, metaxylylene modified novolak resin, and orthoxylylene modified. Xylylene-modified novolak resin such as novolak resin, bisphenol type phenol resin such as bisphenol A type resin and bisphenol F type resin, biphenyl type phenol resin, resol type phenol resin, phenol aralkyl type resin, biphenyl aralkyl type resin, triphenolmethane type resin , Triphenolalkane type resins such as triphenolpropane type resins and phenolic resins such as polymers thereof, phenol resins containing naphthalene rings, dicyclopenta Any phenolic resin, such as ene-modified phenolic resins can be used.

  In particular, the phenolic curing agent of the present invention preferably contains a phenolic curing agent represented by the following general formula (3).

（式中、Ｒ²は二重結合を有する炭素数１０以下の一価炭化水素基であり、具体的には、ビニル基、アリル基、プロペニル基、ブテニル基、ヘキセニル基等のアルケニル基等があげられる。Ｒ³は下記式で示される二価炭化水素基のいずれか一つである。

(Wherein, R ² is a monovalent hydrocarbon group having 10 or less carbon atoms having a double bond, specifically, vinyl-group, allyl group, propenyl group, butenyl group, alkenyl groups such as hexenyl R ³ is any one of divalent hydrocarbon groups represented by the following formula.

（式中、Ｒ⁴は水素原子又は炭素数１０以下、好ましくは１〜５のアルケニル基を除く一価炭化水素基であり、例えばメチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、ｔｅｒｔ−ブチル基等のアルキル基等が挙げられる。）

(In the formula, R ⁴ is a hydrogen atom or a monovalent hydrocarbon group excluding an alkenyl group having 10 or less carbon atoms, preferably 1 to 5, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl. And alkyl groups such as a tert-butyl group).

  The phenolic curing agent represented by the general formula (3) is preferably in a liquid state at normal temperature, and the viscosity at 25 ° C. is preferably 300 Pa · s or less, particularly preferably 100 Pa · s or less. When the viscosity exceeds 300 Pa · s, the viscosity of the composition may increase and workability may deteriorate.

In addition, among the phenolic curing agents, the alkenyl group-containing phenolic curing which is liquid at room temperature in which the alkenyl group content in R ² of the general formula (3) is 10 mol% or more, preferably 30 mol% or more. It is preferable that content of an agent is 25-100 mass% in all the hardening | curing agents, More preferably, it is 50-100 mass%, More preferably, it is 75-100 mass%. If it is less than 25% by mass, the viscosity of the composition may increase and workability may decrease, the elastic modulus at 150 ° C. or higher may increase, or the internal stress after curing may increase and warp may occur.
Examples of such alkenyl group-containing phenolic curing agents include allyl group-containing phenol resins, and specifically, DAL-BPA manufactured by Honshu Chemical Industry.

In addition, R ² in the above general formula (3) is a hydrogen atom or a monovalent hydrocarbon group having 10 or less carbon atoms, preferably 1 to 5 alkenyl groups (particularly alkyl groups) as long as the properties of the present invention are not impaired. ) Or a phenolic curing agent that is solid at room temperature, or a alkenyl group-containing phenolic curing agent that is solid at room temperature, wherein the alkenyl group content in R ² of the general formula (3) is 10 mol% or less. It can also be used together. Examples of this curing agent include Meiwa Kasei DL series. Since this curing agent is solid at room temperature, it is used by mixing in advance with an alkenyl group-containing phenol-based curing agent in which at least 30 mol% of R ^{2 in} the general formula (3) is an alkenyl group, which is liquid at room temperature. It is desirable. Although it does not specifically limit as a mixing method, It is desirable to melt-mix at 120 degreeC.

  In addition, although the addition amount of the hardening | curing agent of this invention is an effective amount which hardens | cures an epoxy resin, and is selected suitably, in the case of a phenol type hardening | curing agent, the epoxy group 1 contained in the liquid epoxy resin of (A) component It is desirable that the phenolic hydroxyl group is 0.7 to 1.3 times mol, particularly 0.8 to 1.2 times mol, per mol.

[(C) Curing accelerator]
Further, the composition of the present invention includes a curing accelerator for curing the liquid epoxy resin as component (A) or for promoting the curing reaction between the liquid epoxy resin and the curing agent as component (B). Is blended. This curing accelerator is not particularly limited as long as it accelerates the curing reaction, but in particular, those containing one or two or more curing accelerator catalysts selected from imidazole compounds, organophosphorus compounds, etc. are added as they are, Or it is preferable to use as a microcapsule type hardening accelerator which encloses the above-mentioned hardening accelerator inside, or those mixtures.

  As the imidazole compound, those represented by the following general formula (4) can be used.

（式中、Ｒ⁵、Ｒ⁶は水素原子、メチル基、エチル基、ヒドロキシメチル基、フェニル基から選ばれるいずれかであり、Ｒ⁷はメチル基、エチル基、ペンタデシル基、ウンデシル基、フェニル基、アリル基から選ばれるいずれかであり、Ｒ⁸は水素原子、メチル基、エチル基、シアノエチル基、ベンジル基又は下記式（５）で示される基から選ばれるいずれかである。）

Wherein R ⁵ and R ⁶ are any one selected from a hydrogen atom, a methyl group, an ethyl group, a hydroxymethyl group, and a phenyl group, and R ⁷ is a methyl group, an ethyl group, a pentadecyl group, an undecyl group, and a phenyl group. And R ⁸ is any one selected from a hydrogen atom, a methyl group, an ethyl group, a cyanoethyl group, a benzyl group, or a group represented by the following formula (5).)

In particular,
2-methylimidazole, 2-ethylimidazole, 1,2-dimethylimidazole, 2,4-dimethylimidazole, 1,2-diethylimidazole, 2-ethyl-4-methylimidazole, 2-heptadecylimidazole, 2-un Decylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 2,4-diamino -6- [2'-Methylimidazolyl- (1) ']-ethyl-S-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1)']-ethyl- S-triazine, 2,4-diamino-6- [2'-undecylimidazolyl] -ethyl- -Triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1) ']-ethyl-S-triazine isocyanuric acid adduct, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2 -Imidazole compounds such as phenyl-4,5-dihydroxymethylimidazole and 2-aryl-4,5-diphenylimidazole.

  The above-mentioned imidazole compound can be added as it is, or can be used as a microcapsule type curing accelerator or a mixture thereof containing the above-mentioned imidazole compound. When an imidazole compound is used as it is as a curing accelerator, it is necessary to promote the curing reaction at a temperature higher than the melting point of the solder bump. Specifically, 2-undecylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2,4-diamino-6- [2′-methylimidazolyl- (1) ′] having a melting point of 180 ° C. or higher. -Ethyl-S-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1) ']-ethyl-S-triazine, 2,4-diamino-6- [2' -Undecylimidazolyl] -ethyl-S-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1) ']-ethyl-S-triazine isocyanuric acid adduct is preferred.

  On the other hand, as an organic phosphorus compound, triorganophosphine such as triphenylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, diphenyltolylphosphine, triphenylphosphine and triphenylborane. Examples include salts of triorganophosphine and triorganoborane such as salts, tetraorganophosphonium such as tetraphenylphosphonium, and salts of tetraorganophosphonium and tetraorganoborate such as a salt of tetraphenylphosphonium and tetraphenylborate. Among these, those represented by the following general formula (6) are preferable.

（式中、Ｒ⁹は水素原子、又は炭素数１〜４のアルキル基又はアルコキシ基である。）
上記Ｒ⁹のアルキル基としては、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、ｔｅｒｔ−ブチル基等が挙げられ、アルコキシ基としては、メトキシ基、エトキシ基等が挙げられ、好ましくは水素原子又はメチル基である。

(In the formula, R ⁹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group.)
Examples of the alkyl group for R ⁹ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a tert-butyl group. Examples of the alkoxy group include a methoxy group and an ethoxy group. Preferably a hydrogen atom or a methyl group.

  The above-mentioned organophosphorus compound can be added as it is, or can be used as a microcapsule type curing accelerator or a mixture thereof encapsulating the organophosphorus compound. When using an organic phosphorus compound as a curing accelerator as it is, it is necessary to accelerate the curing reaction at a temperature equal to or higher than the melting point of the solder bump. Specifically, triphenylphosphine having a good balance between curability and latency is preferable.

  The curing accelerator of the present invention is preferably a microcapsule having an average particle size of 0.5 to 10 μm encapsulating the above-described curing accelerator, that is, a microcapsule type curing accelerator.

  This microcapsule type curing accelerator is a (meth) acrylic monomer, for example, an alkyl ester having 1 to 8 carbon atoms such as an acrylate ester, an itaconic acid ester or a crotonic acid ester, or a hydrogen atom of the alkyl group of this alkyl ester. In which a part or all of is substituted with an allyl group, monofunctional monomers such as styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, vinyl acetate, ethylene glycol (meth) acrylate, polyethylene glycol In the polymers of various monomers such as di (meth) acrylate, divinylbenzene, bisphenol A di (meth) acrylate, methylene bis (meth) acrylamide, etc., the above-mentioned imidazole compounds, organophosphorus compounds, etc. Those that contain a curing accelerator (curing accelerator catalyst) It is, but as the polymer, in particular (meth) polymers acrylate monomers preferably.

  As a method for producing the microcapsule type curing accelerator of the present invention, various methods can be mentioned and can be produced by a conventionally known method. In order to produce a microcapsule type curing accelerator having high productivity and high sphericity. In general, a suspension polymerization method or an emulsion polymerization method is preferably used. For example, JP-A-5-247179 discloses a method of microencapsulating a solid core material mainly composed of amines for epoxy resin curing agent with a radical polymerizable monomer containing an organic acid having a polymerizable double bond. Has been.

  In this case, in order to obtain a high-concentration microcapsule type curing accelerator from the molecular structure of a commonly used curing accelerating catalyst, the total amount of the monomers used with respect to 10 parts by weight of the curing accelerating catalyst. Is preferably 10 to 200 parts by weight, particularly preferably 10 to 100 parts by weight, and further preferably 20 to 50 parts by weight. If the amount is less than 10 parts by weight, it may be difficult for the microcapsules to sufficiently contribute to the potential of the curing accelerating catalyst. If the amount exceeds 200 parts by weight, the ratio of the catalyst is lowered, and sufficient curability is obtained. Must be used in large quantities, which may be economically disadvantageous. That is, the concentration of the curing accelerator contained in the microcapsule can be about 5 to 50% by mass, preferably about 10 to 50% by mass.

  For example, an epoxy resin microcapsule having a solid core substance mainly composed of amines such as an imidazole compound and a polymer of a radical polymerizable monomer containing an organic acid having a polymerizable double bond as a coating layer Can be given. In order to produce this microcapsule, a solid core substance mainly composed of amines is dispersed in an organic solvent that does not dissolve it, and an organic acid having a polymerizable double bond is contained in the dispersion. An epoxy resin microcapsule characterized by radically polymerizing a radically polymerizable monomer monomer to form a coating layer of the polymer on the surface of the core material can be obtained.

  The organic solvent used for the medium is preferably used in an amount of 1 to 20 times, especially 2 to 10 times the volume of the core substance. Although a mixed solvent may be used, it is essential that it has a boiling point higher than the radical polymerization temperature and does not dissolve amines used for the core material. “Does not dissolve amines” means that the solubility of amines is 5% by weight or less, more preferably 2% by weight or less at the radical polymerization temperature.

  The core material may be dispersed by stirring or ultrasonic action. Stirring may be set in a range where the dispersed particles are stably dispersed with a particle size of about 0.1 to 100 μm, more preferably 0.1 to 10 μm.

  Polymerization is carried out in the presence of a radical polymerization catalyst in a dispersion of amines while adding a radical polymerizable monomer. The catalyst is usually added to the dispersion. The polymerization temperature is generally 20 to 100 ° C, more preferably 30 to 80 ° C, but is not limited thereto. The radical polymerizable monomer may be mixed in advance at a predetermined monomer ratio and then gradually added to the dispersion, or a polymerizable double bond-containing organic acid may be added to the system separately. The addition of the polymerizable organic acid may be any of early, intermediate and late. The polymerization is usually completed in about 2 to 10 hours.

  Phosphoric curing accelerator microcapsules are prepared by mixing and kneading a phosphorus curing accelerator serving as a core and a resin serving as a shell, pulverizing the kneaded product, and classifying the mixture so as to obtain a predetermined volume average particle size. Then, it is processed by a mechano-fusion system, and is produced by adhering and fusing to the surface of the phosphorus-based curing accelerator by the frictional heat of fine resin particles.

  The molding material is produced by blending various materials and heating and kneading at about 50 to 100 ° C. If the melting point or softening point is lower than 40 ° C., the shell composition melts or softens during heating and kneading at the time of manufacturing the molding material, and most of the curing accelerator is taken into the molding material, so the reaction starting point is The reaction proceeds to increase the melt viscosity.

  Further, the molding material is usually molded at 200 ° C. or lower, but when the solder bump material is lead-free solder having a melting point of 200 to 240 ° C., it remains in a molten or softened state at a temperature higher than the melting point. It is preferable. If the shell composition is crosslinked, it may not melt or soften at its melting point. In such a case, it is necessary to slightly lower the melt viscosity and control the degree of cross-linking within such a range that this can be avoided.

  Examples of the shell composition include epoxy resin, urethane resin, polyester resin, methacrylate resin, olefin resin, and styrene resin. These can be used after cross-linking as necessary.

  The phosphorus-based curing accelerator of the microcapsule type phosphorus-based curing accelerator is in a form of being included or supported in the shell material. Therefore, it is considered that the reaction starting point with the resin as the reaction component becomes dilute, so that the reaction in the low temperature region is delayed. However, in the vicinity of 130 to 200 ° C., which is the molding temperature of the sealing material, the shell is melted or softened, the phosphorus curing accelerator is taken in, the reaction starting point with the resin is increased, and the reaction proceeds rapidly. Think.

  The microcapsule-type phosphorus curing accelerator according to claim 1 or 2, wherein the shell is a thermosetting resin or a thermoplastic resin having a melting point or a softening point of 40 ° C or higher.

  The average particle size of the microcapsule-type curing catalyst obtained by such a method is preferably 0.5 to 10 μm, and in particular, the average particle size is 0.5 to 10 μm and the maximum particle size is 50 μm or less. In particular, it is preferable to use those having an average particle diameter of 2 to 5 μm and a maximum particle diameter of 20 μm or less. If the average particle size is smaller than 0.5 μm, the specific surface area becomes large and the viscosity when mixed may increase, and if it exceeds 10 μm, dispersion with the resin may become non-uniform and reliability may be lowered. .

  The blending amount of the curing accelerator is preferably 0.1 based on 100 parts by weight of the component (A) liquid epoxy resin when the imidazole compound, organophosphorus compound, etc. are used as they are without being microencapsulated. -15 parts by weight, in particular 0.5-7 parts by weight. If the blending amount is less than 0.1 parts by weight, the curability may be lowered. If the blending amount is more than 15 parts by weight, the curability is excellent but the storage stability may be lowered.

  In addition, the amount of the microcapsule type curing accelerator is 1 to 15 parts by weight, especially 2 to 100 parts by weight of the liquid epoxy resin (A). The amount is preferably 10 parts by weight. If it is less than 1 part by weight, the curability may be lowered, and if it exceeds 15 parts by weight, the curability is excellent, but the storage stability of the composition may be lowered.

  Furthermore, you may use together a microcapsule type hardening accelerator and the above-mentioned hardening accelerator which is not microencapsulated. In this case, with respect to 100 parts by weight of the liquid epoxy resin of component (A), the total of the curing acceleration catalyst encapsulated in the microcapsule and the curing accelerator not microencapsulated is 1 to 15 parts by weight, particularly 2 The amount is preferably 7 parts by weight. If it is less than 1 part by weight, the curability may be lowered, and if it exceeds 15 parts by weight, the curability is excellent, but the storage stability of the composition may be lowered.

[(D) Inorganic filler]
In the present invention, various inorganic fillers conventionally known are added for the purpose of reducing the expansion coefficient. Specifically, fused silica, crystalline silica, alumina, boron nitride, aluminum nitride, silicon nitride, magnesia, magnesium silicate, aluminum or the like is used as the inorganic filler. Among these, spherical fused silica is desirable because it can reduce the viscosity.

  When the liquid epoxy resin composition of the present invention is used as a potting material, it is desirable that the average particle size is 2 to 25 μm and the maximum particle size is 75 μm or less, particularly 50 μm or less. If the average particle size is less than 2 μm, the viscosity increases and there is a fear that a large amount cannot be filled. If it exceeds 25 μm, coarse particles increase, which may lead to clogging in the lead wire. In addition, this average particle diameter and particle diameter can be obtained, for example, by particle size distribution measurement by a laser beam diffraction method, and the average particle diameter can be obtained, for example, as a weight average value (or median diameter). The amount of the filler in this case is 100 parts by weight in total of the organic resin component [that is, the liquid epoxy resin of component (A), the curing agent of component (B), and the modified silicone resin of component (E) described later]. The range of 100 to 600 parts by weight, particularly 200 to 500 parts by weight is preferred.

In order to maintain the shape, it is desirable to use an inorganic filler having an average particle diameter of 0.01 to 0.10 μm which has been surface-treated with a non-reactive organosilicon compound.
The surface treatment is performed to improve the dispersibility of the inorganic filler. When the average particle size of the inorganic filler is less than 0.01 μm, the viscosity of the epoxy resin composition may be high, and workability may be significantly deteriorated. Moreover, when it exceeds 0.10 micrometer, there exists a problem that the shape maintenance of the sealing material before hardening will become difficult.

  Examples of the inorganic filler having an average particle diameter of 0.01 to 0.10 μm include fumed silica such as Aerosil 130, Aerosil 200, Aerosil 300 (trade name, manufactured by Nippon Aerosil Co., Ltd.); Nipsil VN-3-LP Silica such as wet silica (trade name, manufactured by Nippon Silica Kogyo Co., Ltd.) is preferably used.

Examples of non-reactive organosilicon compounds include CH ₃ Si (OCH ₃ ), (CH ₃ ) ₃ SiOCH ₃ , PhSi (OCH ₃ ) ₃ , PhSiCH ₃ (OCH ₃ ) ₂ , {(CH ₃ ) ₃ Si} ₂ NH, CH ₃ CH ₂ Si (OCH ₃ ) _{3 and the} like (wherein “Ph” means a phenyl group).

  In addition, as a surface treatment method for the inorganic filler, the inorganic filler may be previously treated with the non-reactive organosilicon compound, and at the time of preparing the liquid epoxy resin composition of the present invention. The surface treatment may be performed by an integral blend method in which the non-reactive organosilicon compound is added and blended, but the former method is preferred from the viewpoint of suppressing the amount of the non-reactive organosilicon compound used.

  The amount of component (D) used is usually 0.5 to 5% by weight, preferably 2 to 3% by weight, based on the total amount of the liquid epoxy resin composition of the present invention. If the amount used is too small, it becomes difficult to suppress the occurrence of bleed of the liquid component, and conversely, if too large, the thixotropy becomes too high, so that the fluidity of the epoxy resin composition decreases, There is a possibility that it may be difficult to obtain an upper liquid epoxy resin composition.

  In this case, the filling amount of the inorganic filler is 50 to 1,200 parts by weight, particularly 100 to 1,200, based on 100 parts by weight of the total amount of (A) liquid epoxy resin and (B) aromatic amine curing agent. A range of parts by mass is preferred. If the amount is less than 100 parts by mass, the coefficient of expansion is large and there is a risk of inducing cracks in the cooling test. If it exceeds 1,200 parts by mass, the viscosity becomes high and the fluidity may be lowered. A preferable viscosity in this case is 700 Pa · s or less, preferably 500 Pa · s or less at 25 ° C.

  As a compounding quantity of the inorganic filler in this case, it is preferable to mix | blend by 50-400 mass parts with respect to 100 mass parts of total amounts of (A) liquid epoxy resin and (B) aromatic amine type hardening | curing agent, More Preferably it mix | blends in 100-250 mass parts. If it is less than 50 parts by mass, the expansion coefficient is large, and there is a risk of inducing cracks in the cold test. If it exceeds 400 parts by mass, the viscosity will increase and the thin film penetration may be reduced. A preferable viscosity in this case is 250 Pa · s or less, preferably 100 Pa · s or less at 25 ° C.

[Other additives]
The epoxy resin composition of the present invention may be blended with silicone rubber, silicone oil, liquid polybutadiene rubber, thermoplastic resin made of methyl methacrylate-butadiene-styrene, or the like for the purpose of reducing stress.

  Further, for the purpose of further reducing the stress, silicone rubber, silicone oil, liquid polybutadiene rubber, thermoplastic resin composed of methyl methacrylate-butadiene-styrene, and the like may be blended within a range not impairing the effects of the present invention.

  When using the epoxy resin composition obtained by the production method of the present invention, a flux can be added in order to improve wettability and adhesion with various solders. In this case, it may be a commercially available flux or only an active ingredient may be added. This active ingredient is roughly divided into a base resin and an activator. In the former, abietic acid, dehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, neoabietic acid, isopimaric acid, pimaric acid, levopimaric acid, parastrinic acid, in the latter benzoic acid, stearic acid, lactic acid, citric acid, oxalic acid, succinic acid An acid, adipic acid, sebacic acid, etc. are mentioned.

The added amount of the flux is preferably 0.5 to 5 parts by weight, particularly 1 to 3 parts by weight with respect to 100 parts by weight of the whole resin. When the flux is less than 0.5 parts by weight, the effect is not sufficiently obtained, and when it is more than 10 parts by weight, the curing may be insufficient. The method of mixing the flux is not particularly limited, but it is desirable to melt and mix in advance in an epoxy resin or a curing agent and uniformly disperse.
In the liquid epoxy resin composition of the present invention, if necessary, a pigment such as a carbon functional silane for improving adhesion, carbon black and the like, a dye, an antioxidant, a surface treatment agent (γ-glycidoxypropyltrimethoxysilane) Etc.), and other additives can be blended.

[Adjustment of liquid epoxy resin composition]
The liquid epoxy resin composition of the present invention is, for example, a liquid epoxy resin, a curing agent, a curing accelerator, an inorganic filler, a modified silicone resin, and optional components simultaneously or separately as necessary, while subjecting to heat treatment as necessary. Stir, dissolve, mix and disperse. Although the apparatus used for these operations is not particularly limited, a lykai machine equipped with a stirring and heating apparatus, a three roll, a ball mill, a planetary mixer, and the like can be used. Moreover, you may combine these apparatuses suitably.

  Moreover, the molding method and molding conditions of the liquid epoxy resin composition of the present invention can be a conventional method of solder reflow conditions during surface mounting. A typical example is a temperature profile of “normal temperature → 200 to 260 ° C. (within solder melting temperature range) / 1 minute to 5 minutes → normal temperature”. Below the solder melting temperature, solder may not be connected. Above the solder melting temperature, the semiconductor device may fail due to thermal shock due to high temperature. If the maximum reflow temperature state is less than 1 minute, the liquid epoxy resin composition is not sufficiently cured and sufficient adhesive strength is not obtained, and a failure may occur in a drop test or the like. If it is longer than 5 minutes, the semiconductor device may be damaged due to thermal shock caused by high temperature.

  In the liquid epoxy resin composition of the present invention, the glass transition temperature (Tg) of the cured product of this composition is in the range of 30 to 120 ° C, and the dynamic viscoelastic modulus is 150 ° C or higher (particularly 150 to 280 ° C). The ratio (A / B) of the dynamic viscoelastic modulus A of 30 ° C. or less (particularly 0 to 30 ° C.) to B is 100 or more, preferably 100 to 1,000, particularly 200 to 800. The composition has a viscosity of 10,000 poise or less, preferably 10 to 5,000 poise at 25 ° C.

  The Tg and the dynamic viscoelastic modulus ratio (A / B) can be achieved by selecting an epoxy resin and a curing agent (particularly a phenol resin), selecting a blending amount, and the like.

  In the present invention, the viscosity of the liquid epoxy resin composition used as the sealing material is preferably 1,000 Pa · s or less, particularly 500 Pa · s or less at 25 ° C. The molding method and molding conditions for this composition can be conventional methods, but preferably 100 to 120 ° C. for 0.5 hour or longer, and then 150 to 175 ° C. for 0.5 hour or longer. Heat oven cure under conditions. When heating at 100 to 120 ° C. is less than 0.5 hour, voids may occur after curing. Further, if the heating at 150 to 175 ° C. is less than 0.5 hours, sufficient cured product characteristics may not be obtained. In this case, the curing time is appropriately selected according to the heating temperature.

  Here, as a flip chip type semiconductor device used in the present invention, for example, as shown in FIG. 1, for example, a semiconductor chip 3 is usually mounted on a wiring pattern surface of an organic substrate 1 via a plurality of bumps 2. The gap between the organic substrate 1 and the semiconductor chip 3 (the gap between the bumps 2) is filled with the underfill material 4 and the side portion thereof is sealed with the fillet material 5. The sealing material of the present invention is particularly effective when used as such an underfill material.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not restrict | limited to the following Example.

[Examples 1-2 , Reference Examples 3-4, Comparative Examples 1-2 ]
Each component shown in Table 1 was kneaded uniformly with three rolls to obtain six types of liquid epoxy resin compositions. The test shown below was done using these liquid epoxy resin compositions. The results are shown in Table 1.

[viscosity]
About each composition, according to JISZ-8803, measurement temperature: 25 degreeC, the value after 2 minutes was measured using the E-type viscosity meter.

[Thixotropic index]
In the measurement of the viscosity of (a) above, the value of the ratio of the viscosities measured so that the ratio of the low shear to the high shear is 10 times is shown.

[Gelification time]
The gel time of the composition was measured on a hot plate at 200 ° C.

[Tg (glass transition temperature), CTE1 (expansion coefficient), CTE2 (expansion coefficient)]
By using TMA (thermomechanical analyzer) with a cured product specimen cured at 5 ° × 5 mm × 15 mm “normal temperature → 200 to 260 ° C. (within solder melting temperature range) / 30 seconds to 5 minutes → normal temperature”. The temperature was raised at 5 ° C. per minute and Tg was measured. Moreover, the expansion coefficient in the following temperature range was measured by the measured Tg.
When Tg is 30 to 100 ° C., CTE1 is −30 to 0 ° C., CTE2 is an expansion coefficient when the temperature range is 150 to 180 ° C. When Tg is 100 ° C. or more, CTE1 is 50 to 80 ° C., CTE2 is Expansion coefficient in the temperature range of 200-230 ° C

[Elastic modulus ratio]
The elastic modulus of the cured product at 30 ° C. and 200 ° C. was measured by DMA (DMS-120) manufactured by Seiko Co., Ltd., and was shown as the ratio of the elastic modulus at 30 ° C. to the elastic modulus at 200 ° C.

[Presence or absence of injection under the substrate]
After applying a resin composition on a BT substrate (bonding pad; solder) to which a semiconductor element (10 * 10 mm) with solder bumps is bonded, and temporarily bonding with a flip chip bonder, Max temperature is 240 ° C. + / − 5 ° C., Curing was performed in an IR reflow oven set to a profile of 1 minute to 2 minutes at a minimum temperature of 195 ° C., and it was confirmed whether the resin was flowing in the center between the semiconductor element and the BT substrate. What was flowing in the center 3 mm or more from the outer periphery was defined as NG.

[Adhesion test]
A test piece in the shape of a truncated cone having a diameter of 2 mm on the upper surface, a diameter of 5 mm on the lower surface, and a height of 3 mm is placed on the BT substrate coated with the solder resist AUS308, and the Max temperature is 240 ° C. + / − 5 ° C., and the minimum temperature is 195 ° C. for 1 minute. Cured in an IR reflow oven set to a profile of ˜2 minutes. After curing, the shear adhesion of the obtained specimen was measured. In any case, the number of test pieces was five, and the average value was expressed as adhesive strength.

[Solder connection test]
Semiconductor element with solder bumps A resin composition is applied onto a BT substrate (bonding pad; solder) to which semiconductor elements are bonded, and after temporary bonding with a flip chip bonder, a Max temperature of 240 ° C. + / − 5 ° C., a minimum temperature of 195 It hardened | cured with IR reflow oven set to the profile for 1 minute-2 minutes at (degree C), the solder joint property (resistance value) was measured, and the presence or absence of conduction | electrical_connection was confirmed.

[Repairability at 260 ° C]
Semiconductor element with solder bumps A resin composition is applied onto a BT substrate (bonding pad; solder) to which semiconductor elements are bonded, and after temporary bonding with a flip chip bonder, a Max temperature of 240 ° C. + / − 5 ° C., a minimum temperature of 195 It was cured in an IR reflow oven set to a profile of 1 to 2 minutes at 0 ° C., placed on a hot plate set to 260 ° C., and confirmed that the semiconductor element could be removed at 5 MPa or less. Those that can be removed are OK, and those that cannot be removed are NG.

○ YDF8170: Bisphenol F type epoxy resin (manufactured by Toto Kasei)
○ MH700: Methyltetrahydrophthalic anhydride (manufactured by Shin Nippon Rika)
Copolymer:

○ 2PHZ-PW microcapsules: Polymer of methyl methacrylate containing 20% by weight of 2PHZ-PW Average particle size is 7μm Curing accelerating catalyst that elutes from microcapsules in 15-minute treatment in 30 ° C o-cresol mixture Is 87% by weight
○ 2PHZ-PW: 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Chemicals)
○ Curing agent A: DAL-BPA (manufactured by Honshu Chemical Industry Co., Ltd.) Viscosity (25 ° C.) = 16 Pa · s Hydroxyl equivalent = 154
○ Curing agent B: DL92 (Maywa Kasei) Solid at normal temperature Hydroxyl equivalent = 107
○ SE8FC: Spherical silica with an average particle size of 8μm and maximum particle size of 24μm or less (manufactured by Tatsumori)
○ Surface-treated inorganic filler silica M Hexamethylsilazane: Fumed silica surface-treated with SE31 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.): Aerosil 130 (trade name, manufactured by Nippon Aerosil Co., Ltd., average particle size: 0.15 μm)

(A) The state which applied the epoxy resin composition to the outer periphery of an electronic circuit board is shown. (B) A state before the CSP is placed on the pad so that the solder bumps coincide with each other. (C) A state where solder bumps are connected to the pads before reflow. (D) A state in which the solder melt connection and the curing of the epoxy resin composition after completion of the reflow are completed. Shows the time variation of temperature during surface mounting.

Explanation of symbols

1 Electronic circuit board 2 Epoxy resin composition 3 Pad 4 CPS
5 Solder bump

Claims (10)

When a semiconductor component having solder bumps for electrical bonding on a substrate is surface-mounted, the solder bump material has a melting point that is not cured for at least 30 seconds and is applied to all or part of the outer periphery of the semiconductor component package. A thermosetting epoxy resin composition that can be thermally cured after soldering at the time of surface mounting without penetrating between the semiconductor package and the electric circuit board while maintaining the shape, and the thermosetting epoxy resin composition Curing agent containing 25 to 100% by weight of resin represented by the following general formula (3): (A) liquid epoxy resin (B)

(In the formula, R ² is a monovalent hydrocarbon group having 10 or less carbon atoms having a double bond, and R ³ is any one of divalent hydrocarbon groups represented by the following formula.)

(In the formula, R ⁴ is a hydrogen atom or a monovalent hydrocarbon group having 10 or less carbon atoms.)
(C) A microcapsule having an average particle diameter of 0.5 to 10 μm encapsulating an imidazole compound or an organophosphorus compound inside, and a curing accelerator that melts or softens at a temperature equal to or higher than the melting point of the solder bump material. (D) Inorganic filler only containing, thermosetting epoxy resin composition, wherein the viscosity at 25 ° C. as measured using an E-type viscometer is not less than 350 Pa · s.   The thermosetting epoxy resin composition according to claim 1, wherein the curing agent of the component (B) is an allyl group-containing phenol resin DAL-BPA.   The thermosetting epoxy resin composition according to claim 1 or 2, wherein the curing accelerator of the component (C) is an imidazole 2PHZ-PW microcapsule.   The thermosetting epoxy resin composition according to any one of claims 1 to 3, wherein the solder bump material is lead-free solder having a melting point of 200 to 240 ° C.   The thermosetting epoxy resin composition according to any one of claims 1 to 3, wherein the solder bump material is a eutectic solder.   The thermosetting epoxy resin composition according to any one of claims 1 to 5, wherein the solder bump material has an uncured state of 30 seconds or more and less than 5 minutes at the melting point of the solder bump material.   The thermosetting epoxy resin composition according to any one of claims 1 to 6, wherein the thixotropy index before curing is 1.1 to 4.0.   The glass transition temperature (Tg) of the cured product of the thermosetting epoxy resin composition is in the range of 30 to 120 ° C., and the ratio of the dynamic viscoelasticity of 30 ° C. or less to the dynamic viscoelasticity of 150 ° C. or more. Is 100 or more, The composition of any one of Claim 1 thru | or 7 characterized by the above-mentioned.   The composition according to any one of claims 1 to 8, wherein the curing accelerator is a mixture of the microcapsules and an imidazole compound or an organic phosphorus compound.   The semiconductor device sealed with the hardened | cured material of the composition of any one of Claims 1-9.

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