KR100656684B1 - Epoxy resin composition for encapsulating semiconductor device and the semiconductor device using thereof - Google Patents

Abstract

Provided are a thermosetting epoxy resin composition for packaging a semiconductor device which is excellent in fluidity, storage stability and mechanical properties, and a semiconductor device using the composition. The epoxy resin composition comprises an epoxy resin; a curing agent; 0.1-10 wt% of a curing accelerator which is the tetracyanoethylene represented by the formula 1 and/or the 7,7,8,8-tetracyanoquinodimethane represented by the formula 2; and 70-95 wt% of a filler. The content of tetracyanoethylene and/or 7,7,8,8-tetracyanoquinodimethane is 5-95 wt% of the total curing accelerator. Preferably the epoxy resin is a biphenyl epoxy resin represented by the formula 4 (wherein the average of n is 1-7); and the curing agent is a xyloc phenol resin.

Description

Epoxy resin composition for encapsulating semiconductor device and the semiconductor device using

The present invention relates to an epoxy resin composition for sealing semiconductor elements excellent in fluidity and curing properties.

   Epoxy resins are used in various fields such as paints, adhesives, and electrical insulating materials because of excellent heat resistance, moisture resistance, electrical properties, and adhesion. Among them, conventional methods of molding electronic circuit components such as semiconductors include a hermetic molding method using metals and ceramics and a resin molding method using resins such as phenol resins, silicone resins, and epoxy resins. However, the resin molding method using an epoxy resin has been known to be the best from the viewpoint of economy, productivity and physical properties.

   Recently, in the semiconductor package mounting method of a printed circuit board, a surface mounting method of directly soldering a package on a substrate surface has become popular in an insert mounting method for inserting lead pins into a hole in a substrate, which has been used in the past, as density and automation have advanced rapidly. Accordingly, the package is also changed from a conventional dual inline pacakge (DIP) to a thin flat plastic package (FPP) suitable for high density and surface mounting. With the progress of fine processing technology, the degree of integration of semiconductors has dramatically improved, and the occupied area occupied by semiconductor chips in packages has increased, and packages have become larger and more multi-pinned.

   Therefore, if the moldability is not increased in molding such a semiconductor package, mold failure such as unpacking of the package and generation of voids may occur, leading to a decrease in productivity. The semiconductor molding method used in recent years is to make an epoxy resin molding into a tablet state and to mold using a low pressure transfer molding machine. At this time, since the epoxy resin molded article is in a B-stage (B-Stage) state, if left for several days at room temperature or long storage period at low temperature, the curing reaction is performed, resulting in poor moldability. In particular, since aging at room temperature is common before semiconductor molding, moldability is often weakened in this case. In this case, appearance defects (unfilled, voids, pinholes, etc.) and internal defects (gold wire deformation, internal voids, etc.) occur during semiconductor molding, causing problems in the reliability of the semiconductor package such as moisture resistance and soldering heat resistance. The main reason for the aging is that when stored at low temperature and molded directly at room temperature, the surface heat history and the internal heat history of the epoxy resin composition are different, so that many defects occur during molding.

For this reason, various types of curing accelerators have been developed to improve molding characteristics of the resin composition for semiconductor encapsulation (Japanese Patent Laid-Open No. 6-271653, Japanese Patent Laid-Open No. 6-322073, Japanese Patent Laid-Open No. 6-326220). Here, too, the moldability was not improved without lowering the production efficiency. In particular, as the demand for high-density, high heat-resistance, and high moisture resistance of semiconductors requires high-filling technology of inorganic fillers, epoxy resins use biphenyl-type low viscosity epoxy resins in the conventional novolak form. In order to provide an environmentally friendly epoxy resin composition, self-extinguishing resins are used. These biphenyl epoxy resins and self-extinguishing resins have very low reactivity compared to novolak-type epoxy resins and phenolic resins, so that the curing reaction is incomplete when the conventional curing accelerator is used, resulting in incomplete curing reaction. In addition, degradation of curing properties and storage stability appear (WG Kim et al., Journal of Applied Polymer Science, Vol. 96, pp. 2287-2299, 2005).

The present invention is to provide an epoxy resin composition for semiconductor encapsulation, which has excellent reactivity and good storage stability, overcoming the problems of the prior art.

In order to solve the above problems, the present inventors have found that applying a new curing accelerator can provide an epoxy resin composition for sealing semiconductor devices having excellent reactivity and good moldability, curing characteristics, and storage stability, thereby completing the present invention. It became.

Therefore, according to the present invention, in an epoxy resin composition comprising an epoxy resin, a curing agent, a curing accelerator and a filler, the curing accelerator is represented by the following formula (1), tetracyanoethylene or the following formula (2). Provided is an epoxy resin composition for sealing a semiconductor device, comprising 7,7,8,8-tetracyanoquinomethane.

화학식(1)

Formula (1)

화학식(2)

Formula (2)

   Tetracyanoethylene and 7,7,8,8-tetracyanoquinomethane are used together as said hardening accelerator, The epoxy resin composition for semiconductor element sealing is provided.

   The curing accelerator is characterized in that 0.1 to 10% by weight based on the total epoxy resin composition.

   Tetracyanoethylene or 7,7,8,8-tetracyanoquinomethane in the curing accelerator is characterized in that 5 to 95% by weight of the total curing accelerator.

   It characterized in that it comprises an adduct made by pre-reacting the tetracyanoethylene or 7,7,8,8-tetracyanoquinodimethane with the curing agent.

   It is characterized by using a biphenyl type epoxy resin represented by the following formula (4) as the epoxy resin.

화학식(4)

Formula (4)

(In the above formula, the average value of n is 1 to 7.)

   The biphenyl type epoxy resin is characterized by using more than 40% by weight relative to the total epoxy resin.

   The biphenyl type epoxy resin is characterized by using more than 70% by weight relative to the total epoxy resin.

   It is characterized by using a xylol-type phenol resin represented by the following formula (5) as the curing agent.

화학식 (5)

Formula (5)

(In the above formula, the average value of n is 1 to 7.)

   The xylox phenolic resin is characterized by using at least 30% by weight relative to the total curing agent.

   The xylox phenolic resin is characterized by using at least 50% by weight relative to the total curing agent.

   As the filler, a silica containing 50 to 99% by weight of spherical fused silica having an average particle diameter of 5 µm or more and 30 µm or less and 1 to 50% by weight of spherical molten silica having an average particle diameter of 1 µm or less is used.

The filler is characterized by containing 70 to 95% by weight based on the total epoxy resin composition.

The filler is characterized by containing 80 to 95% by weight based on the total epoxy resin composition.

   In this invention, the semiconductor element using the said epoxy resin composition for semiconductor element sealing is provided.

   Hereinafter, the present invention will be described in more detail.

   The present invention relates to an epoxy resin composition for sealing semiconductor elements that can be used in semiconductor devices such as copper lead frames, iron lead frames, and organic laminate frames.

   The epoxy resin composition for sealing a semiconductor device of the present invention is an epoxy resin composition comprising an epoxy resin, a curing agent, a curing accelerator, and a filler, wherein as the curing accelerator, tetracyanoethylene represented by the following formula (1) or the following formula (2): Provided is an epoxy resin composition for sealing a semiconductor device, comprising 7,7,8,8-tetracyanoquinomethane represented by).

화학식(1)

Formula (1)

화학식(2)

Formula (2)

   Examples of the epoxy resin of the present invention include cresol novolac epoxy resins, phenol novolac epoxy resins, biphenyl epoxy resins, bisphenol A epoxy resins, bisphenol F epoxy resins, linear aliphatic epoxy resins, and alicyclic epoxy resins. Resins, heterocyclic epoxy resins, epoxy resins including spiro rings and xylox epoxy resins, phenol aralkyl type epoxy resins, and the like, and two or more of them may be used. For example, the phenol aralkyl type epoxy resin represented by General formula (3) and the biphenyl type epoxy resin represented by General formula (4) are mentioned.

화학식(3)

Formula (3)

(In the above formula, the average value of n is 1 to 7.)

                                                        Formula (4)

 (In the above formula, the average value of n is 1 to 7.)

   Preferred epoxy resins include biphenyl type epoxy resins represented by the above formula (4), and it is preferable to use them at 40 wt% or more, particularly 70 wt% or more, based on the total epoxy resin. The said biphenyl type epoxy resin can exhibit sufficient effect even if it is single or a mixture, and can also be used as an addition compound which made partial reaction to the said biphenyl type epoxy resin. The total epoxy resin used in the present invention is preferably 3 to 15% by weight, more preferably 3 to 12% by weight based on the total epoxy resin composition.

   The curing agent used in the present invention is a substance capable of reacting with an epoxy resin to form a cured product. Specific examples include phenol novolak resins, cresol novolak resins, various novolak resins synthesized from bisphenol A and resol, and tris (hydroxyphenyl). And various polyhydric phenol compounds such as methane and dihydroxybiphenyl, acid anhydrides such as maleic anhydride and phthalic anhydride, and aromatic amines such as metaphenylenediamine, diaminoimphenylmethane and diaminoimphenylsulfone. Phenol-based curing agents are widely used in terms of heat resistance, moisture resistance, and storage properties for semiconductor molding, and two or more kinds of curing agents may be used in parallel depending on the use. For example, a xylox phenol resin represented by General formula (5) and the phenol aralkyl type phenol resin represented by General formula (6) are mentioned.

화학식 (5)

Formula (5)

(In the above formula, the average value of n is 1 to 7.)

화학식 (6)

Formula (6)

(In the above formula, the average value of n is 1 to 7.)

   Preferred phenolic resins include xylol-type phenolic resins such as the formula (5), which is preferably used at least 30% by weight, in particular at least 50% by weight, based on the total phenolic resin. The total curing agent used in the present invention is preferably 0.1 to 10% by weight, more preferably 0.5 to 7% by weight based on the total epoxy resin composition. The ratio of the epoxy resin and the curing agent is preferably used in the chemical equivalence ratio of the curing agent in the range of 0.5 to 1.5, in particular 0.8 to 1.2, depending on the requirements of mechanical properties and moisture resistance reliability.

   The curing accelerator used in the present invention is a substance that promotes the reaction of the epoxy resin and the curing agent. In general, tertiary amines, organometallic compounds, organophosphorus compounds, imidazoles, boron compounds and the like can be used. Tertiary amines include benzyldimethylamine, 2-2- (dimethylaminomethyl) phenol, salts of 2,4,6-tris (diaminomethyl) phenol and tri-2-ethylhexyl acid. Organometallic compounds include chromium acetylacetonate, zinc acetyl acetonate, nickel acetylacetonate and the like. Organophosphorus compounds include tris-4-methoxy phosphine, tetrabutylphosphonium bromide, butyltriphenylphosphonium bromide, triphenylphosphine, triphenylphosphine triphenylborane, triphenylphosphine-1,4-benzoquinone Additives and the like. The imidazoles include 2-methylimidazole, 2-aminoimidazole, 2methyl-1-vinylimidazole, 2-ethyl-4-methylimidazole, 2-heptadecylimidazole and the like. Examples of the boron compound include trifluoroborane-n-hexylamine, trifluoroborane monoethylamine, tetrafluoroborane triethylamine, tetrafluoroboraneamine and the like. In addition, 1, 8- diazabicyclo undecene (DBU), a phenol novolak resin salt, etc. are mentioned.

   However, since the curing properties and moldability of the epoxy resin composition using the low viscosity resin are not improved as such a general curing accelerator, in this study, in order to improve the moldability, storage stability and curing properties of the epoxy resin composition, Tetracyanoethylene or 7,7,8,8-tetracyanoquinomethane of formula (2) is used, and tetracyanoethylene and 7,7,8,8-tetracyanoquinodimethane You may use together. In particular, as a curing accelerator, it is preferable to use a curing accelerator added with tetracyanoethylene or 7,7,8,8-tetracyanoquinomethane to a triphenylphosphine derivative exhibiting excellent properties in flowability of the epoxy resin composition. . Triphenylphosphine derivatives include triphenylphosphine, triphenylphosphine oxide, butyl triphenylphosphine bromide, triphenylphosphine triphenylborate, and especially tricyanoethylene or 7,7 to triphenylphosphine. It is more effective to use an adduct made by pre-reacting a curing accelerator with, 8,8-tetracyanoquinodimethane with a curing agent.

In the epoxy resin composition for sealing semiconductor elements of the present invention, the curing accelerator is preferably contained in an amount of 0.1 to 10% by weight based on the total epoxy resin composition, and the compound represented by the formula (1) is 5 to 95 weight in the total curing accelerator. It is preferable to contain%.

   The filler used in the present invention is a material that effectively improves the mechanical properties and low stress of the epoxy resin composition. Examples generally used include fused silica, crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, antimony oxide, glass fibers and the like. In order to reduce the stress, it is preferable to use molten silica having a low linear window coefficient. The fused silica refers to amorphous silica having a specific gravity of 2.3 or less, and includes crystalline silica made by melting crystalline silica or synthesized from various raw materials. Although the shape and particle diameter of a fused silica are not specifically limited, Silica containing 50-99 weight% of spherical molten silica of 5 micrometers-30 micrometers of average particle diameters, and 1-50 weight% of spherical molten silica of 1 micrometer or less of average particle diameters are used. It is preferably contained at least 40% by weight, preferably at least 60% by weight relative to the total filler. The proportion of the filler in the present invention depends on the physical properties such as moldability, low stress, high temperature strength, etc., preferably 70 to 95% by weight, more preferably 80 to 95% by weight relative to the total epoxy resin composition do.

   In the composition of the present invention, release agents such as higher fatty acids, higher fatty acid metal salts, ester waxes, colorants such as carbon black, organic dyes and inorganic dyes, epoxysilanes, aminosilanes, alkylsilanes, and the like, without departing from the object of the present invention. Coupling agents, modified silicone oils, silicone powders, stress relieving agents such as silicone resins and the like may be used as necessary. At this time, the modified silicone oil is preferably a silicone polymer having excellent heat resistance, and the total epoxy resin composition by mixing one or two or more kinds of a silicone oil having an epoxy functional group, a silicone oil having an amine functional group, and a silicone oil having a carboxyl functional group. 0.05 to 1.5% by weight can be used. However, when the silicon oil exceeds 1.5% by weight or more, surface contamination is likely to occur and the resin bleed may be long, and when used at less than 0.05% by weight, there may be a problem that a sufficient low modulus of elasticity cannot be obtained.

   As a general method for producing an epoxy resin composition using the raw materials described above, a predetermined content is uniformly sufficiently mixed using a Henschel mixer or a Rodige mixer, melt-kneaded with a roll mill or a kneader, and cooled and pulverized. A method of obtaining the final powder product is used. In general, a semiconductor device can be manufactured using the epoxy resin composition obtained in the present invention by using a low pressure transfer molding method or an injection molding method or a casting method.

  Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to Examples.

[Examples 1 to 4]

   Next, the mixture was uniformly mixed using a Henschel mixer according to the composition of Table 1, followed by melt kneading in a range of 100 to 120 ° C. using a continuous kneader, followed by cooling and grinding to prepare an epoxy resin composition for semiconductor molding. Various physical properties were evaluated by the following method. The results are shown in Table 2.

(Fluidity / spiral flow): It measured using the transfer molding press at 175 degreeC using the evaluation mold according to EMMI-1-66.

(Storage stability): at 25 ℃ and 55% RH based on the value of spiral flow before storage

The reduction rate of spiral flow after 96 hours storage was measured. The lower the reduction rate, the better the storage stability.

(Bending strength): A standard specimen was prepared according to ASTM D-790, and then cured for 4 hours at 175 ° C and measured using UTM.

[Comparative Examples 1 to 3]

Next, according to the composition of Table 1 and carried out in the same manner as in the above Example and evaluated the properties are shown in Table 2 the results.

ingredient Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Epoxy Resin I ¹ 7.91 6.63 7.88 6.61 7.94 7.93 7.94 Epoxy Resin II ² - 1.33 - 1.32 - - - Curing Agent ³ 7.31 7.26 7.29 7.24 7.33 7.32 7.33 TPP ⁴ -TCE ⁵ Addendum 0.20 0.20 - - - TPP-TCNQ ⁶ Addendum 0.25 0.25 TPP - - - - 0.15 - - 2MI ⁷ - - - - - - 0.15 DBU ⁸ - - - - - 0.17 - Filler I ⁹ 58.10 58.10 58.10 58.10 58.10 58.10 58.10 Filler II ¹⁰ 16.60 16.60 16.60 16.60 16.60 16.60 16.60 Filler III ¹¹ 8.30 8.30 8.30 8.30 8.30 8.30 8.30 Silane 0.83 0.83 0.83 0.83 0.83 0.83 0.83 Carnauba wax 0.45 0.45 0.45 0.45 0.45 0.45 0.45 Carbon black 0.30 0.30 0.30 0.30 0.30 0.30 0.30

(Unit: weight%)

(week)

  1) Epoxy Resin I: Biphenyl Epoxy Resin (YX-4000H, JER, Epoxy Equivalent = 190)

  2) Epoxy Resin II: Phenolic Aralkyl Type Epoxy Resin (NC-3000, Nippon Kayaku, Epoxy

Equivalent to 270)

  3) Curing agent: Xylox type phenolic resin (MEH-7800-4S, Meihwa Chem., Hydroxyl equivalent = 175)

  4) TPP: Triphenylphosphine

  5) TCE: Tetracyanoethylene

  6) TCNQ: Tetracyanoquinodimethane

  7) 2MI: 2-methyl imidazole

  8) DBU: 1,8-diazabicycloundecene (1,8-diazabicycloundecene)

  9) Filler I: spherical fused silica with an average particle diameter of 28 μm

 10) Filler II: spherical fused silica with an average particle diameter of 6 μm

 11) Filler III: spherical molten silica with an average particle diameter of 1 μm

Evaluation item Spiral Flow (inch) Storage stability (%) Flexural Strength (kgf / ㎡) Example 1 49 8.5 15.4 Example 2 48 9.4 15.8 Example 3 48 8.2 15.6 Example 4 48 8.7 15.7 Comparative Example 1 42 20.3 13.3 Comparative Example 2 40 24.5 13.1 Comparative Example 3 38 25.2 12.8

As described above, the epoxy resin composition according to the present invention is a catalyst for the conventional catalyst of tetracyanoethylene of formula (1) or 7,7,8,8-tetracyanoquinomethane of formula (2) as a curing accelerator. In addition to the system, it was found that the flowability, storage stability and mechanical properties of the epoxy resin composition were very excellent. Therefore, by using the epoxy resin composition for semiconductors according to the present invention, it is possible to manufacture a semiconductor device having excellent moldability and high reliability in forming a semiconductor device.

Claims (15)

In the epoxy resin composition comprising an epoxy resin, a curing agent, a curing accelerator and a filler, the curing accelerator is 7,7,8,8 represented by tetracyanoethylene represented by the following formula (1) or represented by the following formula (2) -An epoxy resin composition for sealing a semiconductor device, comprising tetracyanoquinomimethane.

Formula (1)

Formula (2)    The epoxy resin composition for semiconductor element sealing according to claim 1, wherein tetracyanoethylene and 7,7,8,8-tetracyanoquinomimethane are used in combination as the curing accelerator.    The epoxy resin composition for semiconductor element sealing according to claim 1, wherein the curing accelerator is contained in an amount of 0.1 to 10 wt% based on the total epoxy resin composition.    The epoxy resin composition for sealing a semiconductor device according to claim 1, wherein the tetracyanoethylene or 7,7,8,8-tetracyanoquinodimethane is contained in an amount of 5 to 95% by weight in the total curing accelerator.    The epoxy resin composition for sealing a semiconductor device according to claim 1, further comprising an adduct formed by linearly reacting the tetracyanoethylene or 7,7,8,8-tetracyanoquinomethane with the curing agent.    The epoxy resin composition for sealing a semiconductor device according to claim 1, wherein a biphenyl type epoxy resin represented by the following general formula (4) is used as the epoxy resin.

Formula (4) (In the above formula, the average value of n is 1 to 7.)    The epoxy resin composition for sealing a semiconductor device according to claim 6, wherein the biphenyl epoxy resin is used in an amount of 40 wt% or more based on the total epoxy resin.    The epoxy resin composition for semiconductor element sealing according to claim 6, wherein the biphenyl type epoxy resin is used in an amount of 70% by weight or more based on the total epoxy resin.    The epoxy resin composition for semiconductor element sealing according to claim 1, wherein a xylox phenol resin represented by the following general formula (5) is used as the curing agent.

Formula (5) (In the above formula, the average value of n is 1 to 7.)    10. The epoxy resin composition for semiconductor element sealing according to claim 9, wherein the xylox phenol resin is used in an amount of 30 wt% or more based on the total curing agent.    The epoxy resin composition for sealing a semiconductor device according to claim 9, wherein the xylox phenol resin is used in an amount of 50% by weight or more based on the total curing agent.    The method of claim 1, wherein the filler comprises silica containing 50 to 99% by weight of spherical molten silica having an average particle diameter of 5 µm or more and 30 µm or less and 1 to 50% by weight of spherical molten silica having an average particle diameter of 1 µm or less. An epoxy resin composition for sealing semiconductor elements. The epoxy resin composition for semiconductor element sealing according to claim 1, wherein the filler is contained in an amount of 70 to 95% by weight based on the total epoxy resin composition. The epoxy resin composition for semiconductor element sealing according to claim 1, wherein the filler is contained in an amount of 80 to 95% by weight based on the total epoxy resin composition.    The semiconductor element using the epoxy resin composition for semiconductor element sealing as described in any one of Claims 1-14.