JPH049811B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is a heat cycle resistant, moisture resistant product obtained by blending and dispersing a modified reaction product obtained by modifying an OH group-containing fluororesin and a silane coupling agent into a polyfunctional epoxy compound. The present invention relates to an epoxy resin composition for semiconductor encapsulation that has excellent properties and heat resistance. [Conventional technologies and their problems] Currently, resin encapsulation methods are widely used to encapsulate semiconductor elements such as ICs and LSIs using silicone resin or epoxy resin. Among these, epoxy resin is relatively superior. It is widely used as a resin for semiconductor encapsulation because it provides airtightness and is inexpensive. However, when a large-capacity semiconductor device is sealed with this epoxy resin system, the bonding wires of the device become deformed due to stress caused by shrinkage during curing or stress caused by the difference in expansion coefficient between the internal device and the epoxy resin. , causing derailment or cracks in the device packaging. Therefore, in order to reduce these stresses, we are investigating methods such as adding flexibility imparting agents to the epoxy matrix, or increasing the amount of inorganic fillers added to reduce the expansion coefficient. has been done. However, the addition of a flexibility-imparting agent has the drawback that it lowers the glass transition temperature of the cured resin, resulting in a decrease in electrical properties and moisture resistance in a high temperature range, resulting in unfavorable results. On the other hand, in order to increase the amount of inorganic filler added and reduce the expansion coefficient, it is necessary to add an amount of 80% by weight or more, but in this case, the melt viscosity of the resin composition increases and the fluidity decreases significantly. Further high-pressure molding is required to seal the element. Furthermore, the increase in melt viscosity causes wire flow and wire breakage during molding, resulting in unfavorable conditions. [Problems to be Solved by the Invention] The present invention has been made to solve these problems, and has heat cycle resistance, heat resistance, and moisture resistance that do not damage the element due to the stress caused by the sealing material. The purpose of the present invention is to provide an epoxy resin composition for semiconductor encapsulation that has excellent properties and does not reduce workability in molding IC elements. [Means for Solving the Problems] The present invention provides (a) copolymerization of tetrafluoroethylene or trifluorochloroethylene and vinyl acetate or vinyl acetate and an olefinic hydrocarbon having 2 to 5 carbon atoms; -COO of the polymer
The OH value obtained by hydrolyzing the - group and introducing the -OH group is
100 parts by weight of 10 to 160 mgKOH/g fluororesin and general formula (): (In the formula, Y is a monovalent organic group containing an epoxy group or an amino group, R ₁ , R ₂ and R ₃ are hydrogen atoms,
a phenyl group, an alkyl group having 1 to 6 carbon atoms, or a -OR group (R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms), and at least one of R ₁ , R ₂ and R ₃ is - An epoxy for semiconductor encapsulation containing (b) a polyfunctional epoxy compound and (c) a phenol novolak resin, which is obtained by subjecting 0.1 to 25 parts by weight of a silane coupling agent represented by (OR group) to a modification reaction. A resin composition in which the amount A (parts by weight) of the modification reactant is relative to the amount B (parts by weight) of the polyfunctional epoxy compound and the amount C (parts by weight) of the phenol novolak resin. /(A+B+C)=0.02 to 0.3, and the modified reaction product is used as it is, or the modified reaction product is mixed or reacted with a polyfunctional epoxy compound or a phenol novolak resin and then blended. The present invention relates to an epoxy resin composition. [Operations and Examples] In general, a functional group capable of reacting with an epoxy resin matrix is introduced through a modification reaction between an OH group-containing fluororesin, which is known as a low moisture absorption material with excellent thermal stability, and a silane coupling agent. The modified reaction product provides thermal stability of the resulting epoxy resin composition, and also provides low elastic modulus and low moisture absorption without substantially lowering the glass transition temperature, so it has good heat resistance and moisture resistance. An epoxy resin composition with excellent properties can be obtained. The OH group-containing fluororesin used in the present invention is a copolymer of tetrafluoroethylene or trifluorochloroethylene and vinyl acetate or vinyl acetate and an olefinic hydrocarbon having 2 to 5 carbon atoms. Its number average molecular weight is 500~
100,000 is preferred, and in particular, in order for the resulting epoxy resin composition to have excellent thermal stability, tetrafluoroethylene or trifluorochloroethylene and vinyl acetate or vinyl acetate and the above hydrocarbon are alternately polymerized. Preferably. The obtained polymer is - of vinyl acetate.
An OH group is introduced by hydrolyzing the COO- group. If the number average molecular weight is less than 500, flexibility will be insufficient, and if it exceeds 100,000, the melt viscosity of the resin will increase and workability will deteriorate. Further, the hydrocarbon compound may optionally include a phenyl group,
It is also possible to use those into which an alkyl group or the like is introduced. OH group-containing fluororesin has 10 to 160 mg of OH
A range of KOH/g is used. OH value
If it is less than 10mgKOH/g, there is poor reactivity with the epoxy matrix, and the OH value is 160mgKOH/g.
If this is exceeded, the OH groups remaining unreacted during the modification reaction with the silane coupling agent will adversely affect moisture resistance. The silane coupling agent used in the present invention has the general formula (): (In the formula, Y is an organic group containing an epoxy group or an amino group, R ₁ , R ₂ and R ₃ are a hydrogen atom, a phenyl group, an alkyl group having 1 to 6 carbon atoms, or an -OR group (R is a hydrogen atom) or an alkyl group having 1 to 5 carbon atoms, and at least one of R ₁ , R ₂ and R ₃ is -OR group). Specific examples of the silane coupling agent include γ
-glycidoxypropyltrimethoxysilane, γ
- glycidoxypropyltripentoxysilane,
γ-glycidoxypropyldimethylethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)
Examples include ethyltrimethoxysilane, N-β (aminoethyl)γ-aminopropyltrimethoxysilane, and these can be used alone or in combination of two or more. The modification reaction between the OH group-containing fluororesin and the silane coupling agent is carried out in a solvent such as acetone, ethyl acetate, or ethyl alcohol. In this case, the mixing ratio of the OH group-containing fluororesin and the silane coupling agent is
The range is 0.1 to 25 parts of the silane coupling agent per 100 parts (parts by weight, hereinafter the same). The modified product obtained by modifying the OH group-containing fluororesin and the silane coupling agent is then either removed from the solvent, washed, and dispersed in an epoxy resin, or mixed with a polyfunctional epoxy compound or a phenolic compound. After dispersing and mixing or reacting the lacquer resin in the modified reaction product solution, the solvent is removed and the resin is washed before use. If the amount of the silane coupling agent is less than 0.1 part, the modification reaction will be insufficient, and if it exceeds 25 parts, the reaction of the silane coupling agent alone will occur.
Adversely affects moisture resistance. In addition, the average particle size of the OH group-containing fluororesin is 50 μm.
m or less, use a Henschel mixer (manufactured by Mitsui Miike Manufacturing Co., Ltd.) or the like to apply a silane coupling agent in the range of 0.1 to 10 parts to 100 parts of OH group-containing fluororesin directly or diluted with ethyl alcohol. Process. If the amount of the silane coupling agent is less than 0.1 part, the modification reaction will be insufficient, and if it exceeds 10 parts, the excess silane coupling agent will adversely affect moisture resistance. As the polyfunctional epoxy compound used in the present invention, various types of epoxy resins having an epoxy equivalent of 75 to 250 can be used, such as novolak epoxy resins, bisphenol A epoxy resins, and alicyclic epoxy resins. It is preferable to use novolac type epoxy resins which have excellent high temperature properties, and these epoxy resins may be used alone or in combination of two or more. In addition to these epoxy resins, epoxy resins such as brominated novolak epoxy resins and brominated bisphenol A epoxy resins can be used in combination, if necessary. The phenol novolak resin used in the present invention can be obtained by condensing a phenol compound such as phenol, cresol, xylenol, bisphenol A, resorcinol, etc. with formaldehyde or paraformaldehyde under an acidic catalyst. . The amount of unreacted compounds in the obtained phenol novolac resin is preferably 0.5% or less from the viewpoint of moisture resistance and heat resistance of the IC device. OH group-containing fluororesin and general formula (): (In the formula, Y is a monovalent organic group containing an epoxy group or an amino group, R ₁ , R ₂ and R ₃ are a hydrogen atom, a phenyl group, an alkyl group having 1 to 6 carbon atoms, or -
A silane coupling agent represented by an OR group (R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and at least one of R ₁ , R ₂ and R ₃ is an -OR group) The epoxy resin composition of the present invention can be obtained by using the modified product obtained by the modification reaction as it is, or by mixing or reacting the modified product with a polyfunctional epoxy compound or a phenol novolak resin and then blending and adjusting it. is the amount A (parts) of the modification reactant
is blended in the range of A/[A+B+C]=0.02 to 0.3 with respect to the blending amount B (parts) of the polyfunctional epoxy compound and the blending amount C (parts) of the phenol novolak resin. If it is less than 0.02, the modulus of elasticity will not be sufficiently lowered, and if it exceeds 0.3, the fluidity of the composition will decrease. If necessary, an inorganic filler and a curing accelerator may be added to the epoxy resin composition of the present invention. Examples of the inorganic filler include crystalline silica powder, fused silica powder, alumina powder, talc,
Examples include quartz glass powder, calcium carbonate powder, glass fiber, etc., and the amount of these inorganic fillers added to the epoxy resin composition of the present invention is 50 to 80%.
(% by weight, the same applies hereinafter) is preferably added. 50
If it is less than 80%, the coefficient of linear expansion and curing stress cannot be lowered sufficiently, causing problems such as cracks in IC elements, and if it exceeds 80%, fluidity decreases, causing problems in workability. The blending amount is suitably adjusted within the range of 50 to 80% depending on the required properties. Examples of the curing accelerator include 2-methylimidazole, 2-ethylimidazole, 2-methyl-4-methylimidazole, and 1-benzyl-
Imidazole compounds such as 2-methylimidazole, 2-heptadecylimidazole, 2-undecylimidazole, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, α-Methylbenzyldimethylamine, piperidine, dimethyllaurylamine, dialkylaminomethanolamine, tetramethylguanidine, 2-dimethylamino-2-hydroxypropane, N,N'-dimethylpiperazine, N-methylmorpholine, piperazine, 2-( Tertiary amines and other amine compounds such as (dimethylaminomethyl)phenol, hexamethylenetetramine, 1-hydroxylethyl-2-heptadecylglyoxalidine, 1,8-diazabicyclo(5,4,0)undecene-7 and imidazole compounds. In addition, colorants such as carbon black, mold release agents such as carnauba wax and polyethylene wax, flame release agents such as antimony trioxide, and coupling agents such as γ-glysiloxypropyltrimethoxysilane may be added. good. The above-mentioned various components are mixed using commonly used mixing devices such as rolls, kneaders, laika machines, etc.
It can be easily adjusted using a Henschel mixer (manufactured by Mitsui Miike Seisakusho). Next, the epoxy resin composition of the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Experimental Example 1 (Production of modified reaction products A to I) OH group-containing fluororesin (Lumiflon manufactured by Asahi Glass Co., Ltd.), silane coupling agent, and solvent were adjusted to have the compositions shown in A to I in Table 1, respectively. The mixture was adjusted, added to a Kolben, and sufficiently stirred to obtain a uniform composition. Next, the Kolben was heated to 50°C and reacted for 5 hours, and then the solvent was removed and washed with water to obtain a modified reaction product. Experimental Example 2 (Manufacture of Modified Reactant J) In the same manner as Experimental Example 1, OH group-containing fluororesin (Lumiflon manufactured by Asahi Glass Co., Ltd.), silane coupling agent, and solvent were added so as to have the composition shown in Table 1 J. Adjust the
After the reaction, cresol novolac epoxy resin (epoxy equivalent: 190-210) and 1,8-diazabicyclo (5,4,
0) Add undecene-7 and further add Kolben
The mixture was heated to 50°C and reacted for 5 hours, the solvent was removed, and the mixture was washed with water to obtain a modified reaction product. Experimental Example 3 (Manufacture of Modified Reactant K) In the same manner as in Experimental Example 1, an OH group-containing fluororesin (Lumiflon manufactured by Asahi Glass Co., Ltd.), a silane coupling agent, and a composition shown in K in Table 1 were prepared. After adjusting the solvent and allowing the reaction to occur, phenol novolak resin (OH equivalent: 100-120) was added in the form of flakes and dissolved, the mixture was homogeneously mixed, the solvent was removed, and the modified reaction product was washed with water. I got it. Experimental Example 4 (Manufacture of Modified Reactant L) In the same manner as Experimental Example 1, an OH group-containing fluororesin (Lumiflon manufactured by Asahi Glass Co., Ltd.), a silane coupling agent, and a composition shown in K in Table 1 were prepared. After adjusting the solvent and allowing the reaction to occur, cresol novolak epoxy resin (epoxy equivalent: 190-210) is added in flakes and dissolved, homogeneously mixed, the solvent is removed, and the denaturation is carried out by washing with water. Reactant L was obtained. Experimental Example 5 (Manufacture of modified reaction product M) OH group-containing fluororesin (Lumiflon manufactured by Asahi Glass Co., Ltd.), silane coupling agent, solvent, and curing accelerator were mixed in a Kolben fluoride so as to have the composition shown in M in Table 1. and stirred thoroughly to obtain a uniform composition. Next, the Kolben was heated to 50°C and reacted for 1 hour, and then the solvent was removed and washed with water to obtain a modified reaction product. Experimental Example 6 (Production of Modified Reactant N) An OH group-containing fluororesin (Lumiflon manufactured by Asahi Glass Co., Ltd.) silane coupling agent was adjusted to have the composition shown in Table 1 N, and a Henschel mixer (Mitsui (manufactured by Miike Seisakusho) to obtain a modified reactant N. Experimental Example 7 (Manufacture of modified reaction product O) OH group-containing fluororesin (Lumiflon manufactured by Asahi Glass Co., Ltd.), silane coupling agent, and solvent were adjusted to have the composition shown in Table 1 O, and silane coupling agent was prepared. The diluted solution was subjected to surface treatment using a Henschel mixer (manufactured by Mitsui Miike Seisakusho) to obtain a modified reaction product O. Experimental Example 8 (Production of Modified Reactant P) Distilled water was added as a curing accelerator to the composition shown in Table 1 O, and γ- was added as a silane coupling agent.
A modified reaction product P was obtained in the same manner as in Example 7 except that glycidoxypropyltrimethoxysilane was used.

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【table】

[Table] Examples 1 to 20 and Comparative Examples 1 to 4 As shown in Tables 2 and 3, polyfunctional epoxy compounds, phenol novolac resins (OH
70 to 90°C The mixture was kneaded for 7 minutes between heated rollers, and tablets were formed by a conventional method. The next tablet was heated to 180℃, 80Kg/cm ² ,
Transfer molding was carried out for 1 minute and then heated to 175℃ for 8 hours.
After curing for a period of time, monitor chips for evaluating moisture resistance reliability and test pieces for various evaluations were prepared. Moisture resistance test is PCT (Pressure Cooker Test) 121
The failure occurrence time was measured under conditions of ℃ and 2 atm. In addition, before conducting the moisture resistance test, a monitor chip for evaluating moisture resistance reliability was immersed in a 260°C solder bath for 30 seconds, and then immersed in liquid silicon for 30 seconds and subjected to a heat shock. Summer.
The results are shown in Table 5. In addition, the physical properties of the obtained tablets were examined using various test specimens for evaluation of flexural modulus, glass transition temperature, coefficient of linear expansion, volume resistivity, and fluidity. The results are shown in Table 4.

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〔Effect of the invention〕

As described above, the epoxy resin composition for semiconductor encapsulation of the present invention has excellent heat shock resistance, heat resistance,
It has moisture resistance and does not change its fluidity significantly, so it can be used suitably for encapsulating semiconductors such as ICs and LSIs.

Claims (1)

[Scope of Claims] 1 (a) A polymer obtained by copolymerizing tetrafluoroethylene or trifluorochloroethylene with vinyl acetate or vinyl acetate and an olefinic hydrocarbon having 2 to 5 carbon atoms -
OH which hydrolyzes COO- group and introduces -OH group
100 parts by weight of fluororesin having a value of 10 to 160 mgKOH/g and general formula (): (In the formula, Y is a monovalent organic group containing an epoxy group or an amino group, R ₁ , R ₂ and R ₃ are hydrogen atoms,
a phenyl group, an alkyl group having 1 to 6 carbon atoms, or a -OR group (R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms), and at least one of R ₁ , R ₂ and R ₃ is - An epoxy for semiconductor encapsulation containing (b) a polyfunctional epoxy compound and (c) a phenol novolak resin, which is obtained by subjecting 0.1 to 25 parts by weight of a silane coupling agent represented by (OR group) to a modification reaction. A resin composition in which the amount A (parts by weight) of the modification reactant is relative to the amount B (parts by weight) of the polyfunctional epoxy compound and the amount C (parts by weight) of the phenol novolak resin. /(A+B+C)=0.02 to 0.3, and the modified reaction product is used as it is, or the modified reaction product is mixed or reacted with a polyfunctional epoxy compound or a phenol novolak resin and then blended. Epoxy resin composition.