JP2007294712A - Die bonding paste, and semiconductor device using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rapidly hardening die bonding paste capable of providing a hardened substance excellent in a stress relaxation, generating no void, and extremely excellent in preservation stability, and to provide a highly reliable semiconductor device using it. <P>SOLUTION: The die bonding paste comprises (A) a specific bisphenole A epoxy resin, (B) a specific bisphenole F epoxy resin, (C) a component dicyandiamide, (D) a particularly structured tetrakis phenolic compound, and a clathrate of imidazoles and/or amines and (E) an inorganic filler. The content ratios of the (A) to the (B) are 10:90 to 90:10 by mass ratio, and to the total 100 mass part of the (A) plus the (B), the (C) having a mass part of 0.1 to 10, the (D) having a mass part of 0.1 to 20, and the (E) having a mass part of 100 to 5,000. The die bonding paste is used for the semicondutor device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a cured product having excellent thermal adhesive strength and excellent stress relaxation properties used for bonding a semiconductor element (hereinafter also referred to as a chip) such as an IC or LSI to a metal frame or the like. The present invention relates to a die bonding paste having a short curing time and a very good storage stability, and a highly reliable semiconductor device using the same.

In recent years, chips have become larger due to the higher integration density of semiconductor elements such as IC and LSI. On the other hand, since the 42 alloy frame which is a metal lead frame for joining chips used conventionally is expensive, a copper frame has been used for the purpose of cost reduction. Here, when the size of a chip such as an IC is larger than about 4 to 5 mm square, when the Au-Si eutectic method is used in the mounting process by heating in the assembly process of the IC or the like, the thermal expansion coefficient of the chip and the copper Characteristic defects due to cracks and warping have become a problem due to differences in the coefficient of thermal expansion of the frame.
That is, this is a coefficient of thermal expansion of 3 × 10 ⁻⁶ / ° C. for silicon or the like which is a material of the chip, whereas it is 8 × 10 ⁻⁶ / ° C. for the 42 alloy frame, but 20 × for the copper frame. This is because it becomes as large as 10 ⁻⁶ / ° C. Therefore, a method of using a mounting resin paste in the mounting process is conceivable. However, in the conventional epoxy resin paste, the epoxy resin, which is the main resin component, is a thermosetting resin, and the three-dimensional cross-linking causes the elasticity of the cured product. The rate was high and the strain between the chip and the copper frame could not be absorbed.

In addition, if an epoxy resin that reduces the crosslinking density after curing, for example, a paste containing a large amount of a monoepoxy compound, the elastic modulus of the cured product can be lowered, but there is a problem that the adhesive strength is lowered. It was. Moreover, since an epoxy resin generally has a high viscosity, when an inorganic filler is added to the epoxy resin, the viscosity is further increased, and there is a problem that workability is deteriorated due to stringing at the time of dispensing. When a large amount of solvent is added to improve workability, a new problem that voids are generated arises. A die bonding paste for improving them has been proposed (see, for example, Patent Document 1).
In addition, there is a proposal to lower the elastic modulus by adopting a specific epoxy resin, but conversely, due to the fast curing, the storage stability of the resin, especially the recently demanded room temperature storage performance has been sufficiently required. It does not satisfy (for example, refer to Patent Document 2). Furthermore, a method using a specific inclusion catalyst has been proposed in order to ensure the room temperature storage stability of the resin, but there is no description regarding a die bonding paste specifically for the purpose of reducing the elastic modulus (for example, And Patent Documents 3 and 4).

JP 2001-106767 A JP 11-49843 A JP-A-11-71449 JP 2004-307545 A

  The object of the present invention is not to deteriorate the adhesive strength during heating even in the combination of a large chip such as an IC and a copper frame, and does not cause defective characteristics such as an IC due to chip crack or warpage, that is, excellent in stress relaxation. Another object of the present invention is to provide a die bonding paste that has a cured product, is free of voids, is fast-curing, and has extremely good storage stability, and a highly reliable semiconductor device using the same.

In order to achieve the above-mentioned object, the present inventors have conducted extensive research to develop a die bonding paste containing an epoxy resin as a main resin component. As a result, an epoxy resin having a special chemical structure, dicyandiamide, and curing acceleration The inventors have found that by using a specific clathrate as a compound, a die bonding paste having excellent characteristics and a highly reliable semiconductor device using the same can be obtained, and the present invention has been completed.
That is, the present invention provides the following die bonding paste and semiconductor device.
1. (A) General formula (1)

(In the formula, m and n are integers satisfying 2 ≦ m + n ≦ 20.)
(B) General formula (2)

(In the formula, R ^{1 to} R ⁸ each independently represent a hydrogen atom and a group selected from a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms. K represents an integer of 0 to 3. .)
(C) Dicyandiamide, (D) General formula (3)

(In the formula, X represents (CH ₂ ) _p , and p is an integer of 0 to _3. R ^{9 to} R ¹⁶ each independently represents a hydrogen atom, a lower alkyl group, a substituted or unsubstituted phenyl group, Represents a halogen atom or a lower alkoxy group.)
A clathrate of tetrakisphenol compound represented by formula (I) and an imidazole and / or amine which is a curing accelerating compound for epoxy resin, and (E) an inorganic filler, (A) component and (B) component The content ratio is 10:90 to 90:10 in terms of mass ratio, and (C) component is 0.1 to 10 parts by mass with respect to 100 parts by mass in total of component (A) and component (B). A die bonding paste comprising 0.1 to 20 parts by mass of component D) and 100 to 5000 parts by mass of component (E).
2. 2. The die bonding paste according to 1 above, wherein the content of imidazoles and / or amines in the clathrate of component (D) is 0.1 to 60% by mass.
3. The tetrakisphenol compounds in component (D) are 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-methyl-4-hydroxyphenyl) ethane and 1 , 1,2,2-tetrakis (3,5-dimethyl-4-hydroxyphenyl) ethane, and the imidazole is 2-ethyl-4-methylimidazole and / or 2-methylimidazole 3. The die bonding paste according to 1 or 2 above.
4). A semiconductor device using the die bonding paste according to any one of 1 to 3 above.

  The die bonding paste of the present invention gives a cured product that is excellent in workability, has fast curability, and is excellent in stress relaxation without reducing the adhesive strength during heating. In addition, the storage stability is very good, the pot life is long, the adhesive strength of the cured product is good, and no interfacial peeling occurs between the chip and the frame. By using this die bonding paste, a highly reliable semiconductor device can be obtained.

  In the die bonding paste of the present invention, the (A) component epoxy resin is a bisphenol A type epoxy resin represented by the following general formula (1).

(In the formula, m and n are integers satisfying 2 ≦ m + n ≦ 20.)
In the above general formula (1), if m + n is 2 or more, the flexibility of the die bonding paste is sufficiently expressed, and a reduction in stress is realized. Moreover, heat resistance is maintained, without a crosslinking density falling that m + n is 20 or less.
The epoxy resin as the component (B) is a bisphenol F type epoxy resin represented by the following general formula (2).

In the formula, R ^{1 to} R ⁸ each independently represent a hydrogen atom and a group selected from a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms. Examples of the substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, and t-butyl. Groups, various pentyl groups, various hexyl groups, alkyl groups such as various octyl groups, vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl group and other alkenyl groups, phenyl groups, tolyl groups, xylyl group and other aryl groups, Examples include aralkyl groups such as benzyl group and phenethyl group, and hydrocarbon groups in which these hydrocarbon groups are substituted with halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom.
In the said General formula (2), k is an integer of 0-3, and when k is 3 or less, the viscosity of an epoxy resin does not become high too much and workability | operativity becomes favorable.
The mixing ratio of the (A) component epoxy resin and the (B) component epoxy resin is required to be 10:90 to 90:10 in terms of mass ratio from the viewpoint of the balance between flexibility and heat resistance. This mass ratio is preferably 30:70 to 70:30.

In the die-bonding paste of the present invention, together with the epoxy resins of the components (A) and (B), other epoxy resins and various resins can be used within the range not to impair the effects of the present invention for the purpose of stress relaxation and adhesion. 1 type, or 2 or more types selected from can be used in combination. Other epoxy resins include other bisphenol A type epoxy resins, other bisphenol F type epoxy resins, other glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, multifunctional type epoxy resins, other novolac type epoxy resins, Examples thereof include alicyclic epoxy resins, dicyclopentadiene epoxy resins, and biphenyl epoxy resins.
Examples of the various resins include polyester resins, polybutadiene resins, phenol resins, polyimide resins, silicone resins, polyurethane resins, and xylene resins.

The dicyandiamide as component (C) used in the die bonding paste of the present invention is a curing agent. There is no restriction | limiting in particular as a form of a dicyandiamide, Usually, what is necessary is just a general-purpose thing, such as a paste used for an electronic component material. The content of the component (C) is required to be 0.1 to 10 parts by mass, preferably 1 to 5 parts by mass with respect to 100 parts by mass in total of the components (A) and (B). .
In the present invention, the clathrate of component (D) is used as a curing accelerating compound for epoxy resin, and is a tetrakisphenol compound represented by the following general formula (3) and a curing accelerating compound for epoxy resin. It is an inclusion body with certain imidazoles and / or amines. Here, the curing accelerator compound for epoxy resin includes a curing agent for epoxy resin and a curing accelerator.

Wherein, X represents a (CH _{2) s,} p is an integer of 0 to 3. R ^{9 to} R ¹⁶ each independently represent a hydrogen atom, a lower alkyl group, a substituted or unsubstituted phenyl group, a halogen atom or a lower alkoxy group. Examples of the lower alkyl group include alkyl groups having 1 to 6 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-hexyl group, and cyclohexyl group. Can be mentioned. Examples of the substituted or unsubstituted phenyl group include a phenyl group which may be substituted with a halogen atom, a lower alkyl group or the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. As a lower alkoxy group, C1-C6 alkoxy groups, such as a methoxy group, an ethoxy group, and t-butoxy group, are mentioned.

  Specific examples of the tetrakisphenol compound represented by the general formula (3) include 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-methyl). -4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3,5-dimethyl-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-chloro-4-hydroxyphenyl) Ethane, 1,1,2,2-tetrakis (3,5-dichloro-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-bromo-4-hydroxyphenyl) ethane, 1,1, 2,2-tetrakis (3,5-dibromo-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-tert-butyl-4-hydroxyphenyl) ethane, 1,1, , 2-Tetrakis (3,5-di-t-butyl-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-fluoro-4-hydroxyphenyl) ethane, 1,1,2,2 Tetrakis (3,5-difluoro-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-methoxy-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3,5 -Dimethoxy-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-chloro-5-methyl-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-bromo-5 -Methyl-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-methoxy-5-methyl-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis ( -T-butyl-5-methyl-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-chloro-5-bromo-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-chloro-5-phenyl-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis [(4-hydroxy-3-phenyl) phenyl] ethane,

1,1,3,3-tetrakis (4-hydroxyphenyl) propane, 1,1,3,3-tetrakis (3-methyl-4-hydroxyphenyl) propane, 1,1,3,3-tetrakis (3, 5-dimethyl-4-hydroxyphenyl) propane, 1,1,3,3-tetrakis (3-chloro-4-hydroxyphenyl) propane, 1,1,3,3-tetrakis (3,5-dichloro-4- Hydroxyphenyl) propane, 1,1,3,3-tetrakis (3-bromo-4-hydroxyphenyl) propane, 1,1,3,3-tetrakis (3,5-dibromo-4-hydroxyphenyl) propane, , 1,3,3-tetrakis (3-phenyl-4-hydroxyphenyl) propane, 1,1,3,3-tetrakis (3,5-diphenyl-4-hydroxyphenyl) Propane, 1,1,3,3-tetrakis (3-methoxy-4-hydroxyphenyl) propane, 1,1,3,3-tetrakis (3,5-dimethoxy-4-hydroxyphenyl) propane, 1, 1,3,3-tetrakis (3-t-butyl-4-hydroxyphenyl) propane, 1,1,3,3-tetrakis (3,5-di-t-butyl-4-hydroxyphenyl) propane,

1,1,4,4-tetrakis (4-hydroxyphenyl) butane, 1,1,4,4-tetrakis (3-methyl-4-hydroxyphenyl) butane, 1,1,4,4-tetrakis (3 5-dimethyl-4-hydroxyphenyl) butane, 1,1,4,4-tetrakis (3-chloro-4-hydroxyphenyl) butane, 1,1,4,4-tetrakis (3,5-dichloro-4-) Hydroxyphenyl) butane, 1,1,4,4-tetrakis (3-methoxy-4-hydroxyphenyl) butane, 1,1,4,4-tetrakis (3,5-dimethoxy-4-hydroxyphenyl) butane, , 1,4,4-tetrakis (3-bromo-4-hydroxyphenyl) butane, 1,1,4,4-tetrakis (3,5-dibromo-4-hydroxyphenyl) butane, Examples include 1,4,4-tetrakis (3-t-butyl-4-hydroxyphenyl) butane, 1,1,4,4-tetrakis (3,5-di-t-butyl-4-hydroxyphenyl) butane can do. These tetrakisphenol compounds may be used alone or in combination of two or more.
Among these tetrakisphenol compounds, in the present invention, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-methyl-4-hydroxyphenyl) ) Ethane and 1,1,2,2-tetrakis (3,5-dimethyl-4-hydroxyphenyl) ethane are preferred.

Examples of guest compound imidazoles to be included by these tetrakisphenol compounds include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 2-n-propylimidazole, 2-undecyl-1H-imidazole. 2-heptadecyl-1H-imidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-1H-imidazole, 4-methyl-2-phenyl-1H-imidazole, 2-phenyl-4 -Methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl 2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazolium trimellitate, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2 , 4-Diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- (2'-undecylimidazolyl- (1'))-ethyl- s-triazine, 2,4-diamino-6- [2'-ethyl-4-imidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- ( 1 ′)]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid Additives, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-cyanoethyl-2-phenyl-4,5-di (2-cyanoethoxy) methylimidazole 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 1-benzyl-2-phenylimidazole hydrochloride and 1-benzyl-2-phenylimidazolium trimellitate.
These may be used alone or in combination of two or more. Among these imidazoles, 2-ethyl-4-methylimidazole and 2-methylimidazole are preferable in the present invention.

  On the other hand, as amines of guest compounds, for example, aliphatic amines, alicyclic amines, heterocyclic amines, aromatic amines and modified amines are used. Aliphatic amines include ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenediamine, dimethylaminopropylamine, diethylaminopropylamine, trimethylhexamethylenediamine, Pentanediamine, bis (2-dimethylaminoethyl) ether, pentamethyldiethylenetriamine, 1,4-diazabicyclo [2.2.2] octane (triethylenediamine), N, N, N ′, N′-tetramethylhexamethylenediamine N, N, N ′, N′-tetramethylpropylenediamine, N, N, N ′, N′-tetramethylethylenediamine, N, N-dimethylcyclohexylamine, dimethylamino Such as butoxy ethoxy ethanol and dimethylamino hexanol and the like.

  Alicyclic and heterocyclic amines include piperidine, piperazine, menthanediamine, isophoronediamine, methylmorpholine, ethylmorpholine, N, N ', N "-tris (dimethylaminopropyl) hexahydro-s-triazine, 3, 9-bis (3-aminopropyl) -2,4,8,10-tetraoxyspiro [5,5] undecane adduct, N-aminoethylpiperazine, trimethylaminoethylpiperazine, bis (4-aminocyclohexyl) methane, N , N′-dimethylpiperazine and 1,8-diazabicyclo [4.5.0] undecene-7.

Examples of aromatic amines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, benzylmethylamine, dimethylbenzylamine, m-xylylenediamine, pyridine and picoline. .
Modified polyamines include epoxy compound-added polyamines, Michael-added polyamines, Mannich-added polyamines, thiourea-added polyamines, ketone-capped polyamines, and other amines such as dicyandiamide, guanidine, organic acid hydrazide, diaminomaleonitrile, amineimide, boron trifluoride. -Piperidine complex, boron trifluoride-monoethylamine complex, etc. are mentioned.
These may be used alone or in combination of two or more. Among these amines, ethylenediamine and diethylenetriamine are preferable in the present invention.

(D) The inclusion body of a component can be used individually by 1 type or in combination of 2 or more types. In the present invention, the content of imidazoles and / or amines in the clathrate of component (D) is usually about 0.1 to 60% by mass, preferably 10 to 50% by mass. Moreover, content of this clathrate in die-bonding paste can be made to be the same as the quantity by which they are normally used as imidazoles and amines.
In the present invention, the clathrate content of the component (D) needs to be 0.1 to 20 parts by mass with respect to a total of 100 parts by mass of the component (A) and the component (B), preferably Is 5 to 15 parts by mass.

  The clathrate of component (D) can be obtained by reacting a tetrakisphenol compound that is a host compound with an imidazole and / or an amine that is a curing accelerating compound of the guest compound. In general, for example, when the guest compound is a liquid, the reaction between the tetrakisphenol compound and the guest compound can be performed by directly adding the tetrakisphenol compound to the liquid. In addition, when the guest compound is a solid, the tetrakisphenol compound is put into the liquid containing those compounds and reacted, or the solid guest compound and the powdered tetrakisphenol compound are reacted in a solid phase. Thus, an inclusion body of a tetrakisphenol compound and a guest compound can be obtained. By such a reaction, an inclusion body is produced with high selectivity and high yield. The clathrate is formed by the guest compound molecules entering the crystal lattice vacancies formed by the host compound molecules. Therefore, which compound is easily taken up as a guest is governed by the molecular size, solidity, polarity, solubility, etc. of the guest compound. The clathrate produced is a crystalline solid.

  When the clathrate of component (D) is blended with the epoxy resin of components (A) and (B), the thermal stability, which is extremely important in controlling the curing reaction, is the guest compound (imidazoles and imidazoles) in the clathrate. (Or amines), which is remarkably improved as compared with the case of adding only amines). The clathrate of component (D) has good moisture resistance during storage and does not decompose or sublime. In addition, the die bonding paste of the present invention containing the clathrate (D) as a curing accelerator or a curing accelerator is excellent in thermal characteristics. The thermal characteristics of the die bonding paste are required to have three characteristics: stability at normal temperature (one-component stability), thermal stability during heating from normal temperature to a desired curing temperature, and curing temperature. The uncured epoxy resin blended with the clathrate of component (D) is extremely stable at room temperature (good one-component stability), but is cured only by heating to a certain temperature above a certain temperature, and quickly Give the desired cured product. In addition, when a known curing agent having relatively excellent thermal stability is used, the curing start temperature is as high as 150 to 180 ° C., and the die bonding paste of the present invention can be cured at a lower temperature than these. You can say that.

Examples of the inorganic filler (E) used in the present invention include metal powders such as silver powder and copper powder, alumina powder, and silica filler. Metal powder such as silver powder is used for imparting conductivity to the cured die bonding paste, and the content of ionic impurities such as halogen ions and alkali metal ions is preferably 20 mass ppm or less. . The shape of the metal powder or the like may be any of a scale shape, a flake shape, a spherical shape, and the like. The particle size of the metal powder varies depending on the required viscosity of the paste, but the average particle size is usually 1 to 15 μm, preferably 1 to 10 μm, and the maximum allowable particle size is about 50 μm. If the average particle size is 1 μm or more, the paste has an appropriate viscosity, and if it is 15 μm or less, bleeding of the epoxy resins of the components (A) and (B) is suppressed when the paste is applied and during curing. The In addition, the metal powder can be used by mixing relatively coarse and fine metal powders, and the above-mentioned various kinds of metal powders may be appropriately mixed and used.
The average particle size of the silica filler is usually 1 to 25 μm, preferably 1 to 10 μm, and the maximum allowable particle size is about 50 μm. If the average particle size is 1 μm or more, the paste has an appropriate viscosity, and if it is 25 μm or less, bleeding of the epoxy resin of the components (A) and (B) is suppressed when the paste is applied and during curing. .

In both the metal powder and the silica filler, when the maximum particle size greatly exceeds 50 μm, when the paste is applied with a dispenser, the needle outlet is blocked, and continuous use for a long time cannot be performed. Moreover, in the case of a silica filler, it is also possible to use a mixture of relatively coarse and fine ones, and various shapes similar to the above metal powder may be appropriately mixed and used. Furthermore, you may mix inorganic fillers other than a metal powder and a silica filler in order to provide the required characteristic.
(E) Content of the inorganic filler of a component is 100-5000 mass parts with respect to a total of 100 mass parts of (A) component and (B) component, Preferably it is 100-4000 mass parts, More preferably, it is 300-1000. Part by mass. If content of an inorganic filler is 100 mass parts or more, the expansion coefficient of a paste hardened | cured material will not become large too much, and the reliability of a connection will become favorable.

A silane coupling agent can be further added to the die bonding paste of the present invention as the component (F). From the viewpoint of obtaining good adhesion, this silane coupling agent is, for example, an epoxy silane coupling agent such as γ-glycidoxypropyltrimethoxysilane, or an amino silane coupling such as γ-aminopropylmethyldimethoxysilane. And a mercapto silane coupling agent such as γ-mercaptopropyltrimethoxysilane. These can be used alone or in combination of two or more. Of these silane coupling agents, epoxy silane coupling agents are preferred.
Further, the content of the silane coupling agent is preferably in the range of 0.01 to 2.0 mass%, more preferably 0.1 to 1.5 mass%, based on the amount of the cured product of the die bonding paste of the present invention. preferable. Sufficient adhesiveness is expressed by setting it to 0.01% by mass or more, and it is sufficient to suppress generation of bubbles caused by outgas, that is, a silane coupling agent, by setting it to 2.0% by mass or less. Can exhibit excellent adhesiveness.

In the die bonding paste of the present invention, a reactive diluent can be further blended as the component (G). Examples of the reactive diluent include n-butyl glycidyl ether, t-butylphenyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, styrene oxide, phenyl glycidyl ether and cresyl glycidyl ether. These may be used singly or in combination of two or more. In the present invention, t-butylphenyl glycidyl ether or cresyl glycidyl ether containing an epoxy group is preferable.
It is preferable that the usage-amount of a reaction diluent is the range of 0.1-10 mass% based on the hardened | cured material amount of the die-bonding paste of this invention.
In the die bonding paste of the present invention, in addition to the above components, a solvent for adjusting the viscosity of the die bonding paste, an adhesion improver such as an acid anhydride, a fine silica powder, an antifoaming agent, and other various additives Can be blended within a range that does not interfere with the function of the die bonding paste.
Examples of the solvent include cellosolve acetate, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carbitol acetate, propylene glycol phenyl ether, diethylene glycol dimethyl ether and diacetone alcohol. These may be used singly or in combination of two or more.

The die bonding paste of the present invention includes the above-described (A) and (B) component epoxy resins, (C) component dicyandiamide, (D) component clathrate, (E) component inorganic filler, and as necessary. Add the silane coupling agent of component (F), the reactive diluent of component (G), other additives, etc., mix well, and then knead with a disperser, kneader, three-roll mill, etc. Then, it can be easily prepared by defoaming.
The die bonding paste of the present invention thus obtained can be cured at low temperature and has excellent workability because it has little stringiness and spreadability, and even when combined with a large chip such as an IC and a copper frame, Does not reduce the adhesive strength. In addition, IC defects due to chip cracks and warpage do not occur, that is, a cured product with excellent stress relaxation properties is provided, storage stability is extremely good, pot life is long, and voids are generated in the cured product. In addition, the adhesive strength of the cured product is good, and no interfacial peeling occurs between the chip and the frame.

For example, the die bonding paste of the present invention can be filled in a syringe and applied onto a substrate using a dispenser, and then a semiconductor element can be mounted and the semiconductor element can be bonded onto the substrate by curing the paste. Furthermore, the resin-sealed semiconductor device of the present invention can be manufactured by performing wire bonding and sealing with a resin that is a sealing agent.
In addition, since the die bonding paste of the present invention has extremely good storage stability, the use of the die bonding paste of the present invention greatly reduces the loss of initial performance during storage and can be expected to improve quality. In addition, storage and management are facilitated, which can contribute to the rationalization of production.
Further, when the die bonding paste of the present invention is used, it is possible to cure in a short time within 3 minutes, which has been difficult to achieve conventionally. Curing is preferably performed by heating at a temperature of 180 ° C. or higher. However, even if curing is performed within 3 minutes, characteristics such as adhesive performance can be achieved in filling. In terms of improving productivity, curing in a short time is effective. Practically, the curing temperature and curing time should be determined in consideration of productivity and hot adhesive strength.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples. In addition, the component used in each example is as follows.
(1) Epoxy resin A [modified bisphenol A type glycidyl ether: EP-4005 manufactured by Asahi Denka Kogyo Co., Ltd., epoxy equivalent 510]
(2) Epoxy resin B [Bisphenol F glycidyl ether: “Japan Epoxy Resin Co., Ltd.” YL983U, epoxy equivalent 170]
(3) Compound (C): Curing agent [Dicyandiamide: “Nippon Carbide Co., Ltd.”]
(4) Compound (D): Curing accelerator (inclusion body A) [“Nippon Soda Co., Ltd.” TEP-2E4MZ, 2-ethyl-4-methylimidazole content 28-32 mass%]
(5) Compound (D): Curing agent (inclusion body B) [TEP-ED manufactured by Nippon Soda Co., Ltd., ethylenediamine 28-32% by mass]
(6) Silver powder: (scale-like, tap density 4.5 g / cm ³ , specific surface area 0.53 m ² / g)
(7) Silica powder: [Spherical silica with an average particle diameter of 2 μm: SO-E5 manufactured by ADMATEX Co., Ltd.]
(8) Coupling agent A: (3-glycidoxypropyltrimethoxysilane)
(9) Coupling agent B: (γ-methacryloxypropyltrimethoxysilane)
(10) Reactive diluent: [t-butylphenylglycidyl ether: PGE-H manufactured by Nippon Kayaku Co., Ltd.]
(11) Curing accelerator: [2-Ethyl-4-methylimidazole: 2E4MZ-CN manufactured by "Shikoku Chemicals Co., Ltd.]

Examples 1-7 and Comparative Examples 1-5
Thoroughly mix the types and amounts of the components shown in Table 1 and Table 2, and then knead at 25 ° C using three rolls to prepare a die bonding paste. Its properties (viscosity, workability, storage stability) ) Was determined by the method shown below. Next, using the obtained die bonding paste, the semiconductor chip and the substrate were bonded and cured, and cured product characteristics (chip bonding strength, thermal conductivity, water absorption rate) were determined by the following methods. These results are shown in Tables 1 and 2.

[Characteristics of die bonding paste]
(1) Viscosity Using an E-type viscometer (3 ° cone, 0.5 rpm and 5 rpm), the viscosity at a temperature of 25 ° C. was measured. In Tables 1 and 2, only the viscosity at 0.5 rpm was described (unit: Pa · s).
(2) Thixotropic property The ratio of the viscosity values at 0.5 rpm and 5 rpm was used as an index of thixotropic property.
(3) Workability (a) Threading property Dispensing threading property was evaluated according to the following criteria.
○: No threading △: Slightly stringing ×: Many threadings occurred (b) Spreadability 0.1mm ³ of paste is applied onto a copper frame whose surface is silver-plated and immediately prepared (18mm square glass) The diameter of the spread area of the paste when a load of 196 mN was applied for 10 seconds was measured and evaluated according to the following criteria. The measurement was performed in a room at 25 ° C.
○: 5 mm or more △: 3-5 mm
X: Less than 3 mm (4) Storage stability The temperature was measured at 25 ° C., 24 hours later and 96 hours later, and the rate of increase relative to the viscosity immediately after blending was used as an index of storage stability.

[Characteristics of cured die bonding paste]
(1) Void Voids were observed by a soft X-ray transmission method for the sample before measuring the adhesive strength.
(2) Chip Adhesive Strength The adhesive strength between the silicon chip (4 mm square) and the substrate (Cu / Ag plated lead frame) was measured under the conditions of temperature: 260 ° C. and measurement method: die shear strength (unit: N).
In the table showing the adhesive strength, Si vs Cu / Ag is the adhesive strength between the silicon chip and the Cu / Ag plated lead frame, Si vs PPF is the adhesive strength between the silicon chip and the PPF frame, and Au vs PPF is the silicon chip. The adhesion strength between the silicon back Au plated chip and the PPF frame is shown.
(3) Shear fracture mode The state of the paste cured material broken in the chip bond strength evaluation test of (2) was visually confirmed.
○: Cohesive failure of the cured paste layer ×: Interfacial peeling (4) Elastic modulus The elastic modulus of the tensile mode was measured at 25 ° C. and 260 ° C. with a thermal analyzer DMA (manufactured by T.A. Instruments Japan, DMAQ800). did. The heating rate is 10 ° C./min (unit: GPa).
(5) Water Absorption Rate The mass change rate after exposure for 24 hours in an environment of 85 ° C. and RH 85% was measured and used as the water absorption rate (unit: mass%).
(6) Warp of chip After applying a paste on a copper frame and mounting an 8 × 8 mm silicon chip on the coated surface, the paste was adhesively cured and the amount of warpage was measured (unit: μm). Curing was performed at 180 ° C. for 2.0 hours for the samples used in Examples 1 to 6 and Comparative Examples 1 to 5, and at 220 ° C. for 3.0 minutes for the samples used in Example 7 and Comparative Example 6.

  As can be seen from Tables 1 and 2, the die bonding paste of the example has less stringiness and spreadability than the paste of the comparative example. Therefore, workability is good, and the characteristics are sufficiently exhibited even in a short time of curing within 3 minutes. In addition, the storage stability (storage at room temperature) is extremely good, and even in various combinations of chips and frames, it exhibits good chip adhesion strength, and interfacial delamination occurs between the paste cured product and the chips or frames (substrates). Good shear failure mode was exhibited. Further, the cured product of the die bonding paste of the present invention has a low water absorption rate, a small chip warp, and excellent properties.

  The die bonding paste of the present invention provides a cured product having good storage stability and workability and excellent stress relaxation properties, and the reliability of the semiconductor device can be improved by using this die bonding paste.

Claims (4)

(A) General formula (1)

(In the formula, m and n are integers satisfying 2 ≦ m + n ≦ 20.)
(B) General formula (2)

(In the formula, R ^{1 to} R ⁸ each independently represent a hydrogen atom and a group selected from a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms. K represents an integer of 0 to 3. .)
(C) Dicyandiamide, (D) General formula (3)

(In the formula, X represents (CH ₂ ) _p , and p is an integer of 0 to _3. R ^{9 to} R ¹⁶ each independently represents a hydrogen atom, a lower alkyl group, a substituted or unsubstituted phenyl group, Represents a halogen atom or a lower alkoxy group.)
Containing an inclusion body of a tetrakisphenol compound represented by the formula (I) and an imidazole and / or amine that is a curing accelerating compound for an epoxy resin, and (E) an inorganic filler, A content rate is 10: 90-90: 10 by mass ratio, and (C) component is 0.1-10 mass parts with respect to a total of 100 mass parts of (A) component and (B) component, (D A die bonding paste comprising 0.1 to 20 parts by mass of component (E) and 100 to 5000 parts by mass of component (E).   The die bonding paste according to claim 1, wherein the content of imidazoles and / or amines in the clathrate of component (D) is 0.1 to 60% by mass.   The tetrakisphenol compounds in component (D) are 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-methyl-4-hydroxyphenyl) ethane and 1 , 1,2,2-tetrakis (3,5-dimethyl-4-hydroxyphenyl) ethane, and the imidazole is 2-ethyl-4-methylimidazole and / or 2-methylimidazole The die bonding paste according to claim 1 or 2.   A semiconductor device using the die bonding paste according to claim 1.