JP2008274041A - Epoxy resin composition for semiconductor encapsulation and resin-encapsulated semiconductor device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition excellent in reliability such as moldability and reflow resistance, having no segregation of an inorganic filler in the internal of a package in a package style of WBGA, and excellent in laser mark characteristics, and a semiconductor device using the same. <P>SOLUTION: The epoxy resin composition includes an epoxy resin (A), a curing agent (B), a curing accelerator (C), and an inorganic filler (D) wherein the inorganic filler (D) has an average particle diameter of not greater than 13 μm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an epoxy resin composition for semiconductor encapsulation and a resin-encapsulated semiconductor device using the same.

  In recent years, high-density mounting of electronic components on printed wiring boards has been progressing. Along with this, semiconductor devices have been mainly surface mount type packages rather than conventional pin insertion type packages, and the form of the packages is more from QFP (Quad Flat Package), SOP (Small Outline Package) and so on. It is shifting to CSP (Chip Size Package) and BGA (Ball Grid Array) that can easily cope with the increase in the number of pins and can be mounted at higher density.

  In the memory field, TSOP (Thin Small Outline Package) using LOC (Lead on Chip) technology has been the mainstream as a package applied to DDR and SDRAM. However, when a package such as a DDR2 SDRAM that requires a higher speed operation is required, even a BGA (Fine pitch BGA) type package is a WBGA (Window BGA) having a BOC (Board on Chip) structure capable of high speed operation at a low cost. The transition is progressing. A typical structure of WBGA is shown in FIG.

Japanese Patent Publication No. 06-68010 Japanese Patent No. 2985864

  WBGA has a flow path in the package as shown in FIGS. 2 and 3 of the sealing resin, and the inventors have found that segregation of the inorganic filler is likely to occur. When such segregation of the inorganic filler occurs, there is a high possibility that the laser mark has a non-uniform color tone at the mark portion.

  The present invention has been made in view of the above, and has excellent reliability such as moldability and reflow resistance, and there is no segregation of the inorganic filler inside the package in the package form of WBGA, and the laser mark property is excellent. Another object of the present invention is to provide an epoxy resin composition and a resin-encapsulated semiconductor device using the same.

  As a result of intensive studies to solve the above-mentioned problems, the inventors compounded an epoxy resin, a curing agent, a curing accelerator and an inorganic filler, and in particular, the average particle size of the inorganic filler should be 13 μm or less. Thus, the present inventors have found that the object can be achieved and have completed the present invention.

  Examples of applications that limit the particle size of the inorganic filler contained in the sealing resin composition include Japanese Patent Publication No. 06-68010 and Japanese Patent No. 2985864. These inventions focus on improving cracks in the soldering process. On the other hand, the present invention pays attention to the special structure of WBGA, finds that segregation of the inorganic filler during the molding of WBGA is greatly related to the particle size, avoids this, and improves the laser mark property. In order to make it possible to regulate the particle size of the inorganic filler

The present invention includes an epoxy resin composition comprising (A) an epoxy resin, (B) a curing agent, (C) a curing accelerator, and (D) an inorganic filler, wherein the inorganic filler has an average particle size of 13 μm or less. About.
Moreover, this invention relates to the said epoxy resin composition whose inorganic filler is 70 weight% or more.
The present invention also relates to a resin-encapsulated semiconductor device having a WBGA package form in which a semiconductor element is encapsulated using the epoxy resin composition.

  According to the present invention, a sealing material excellent in laser mark property and a semiconductor device using the same can be obtained without causing segregation of the inorganic filler in WBGA.

  The (A) epoxy resin of this invention is not specifically limited, The epoxy resin generally used with the epoxy resin molding material for sealing can be used. For example, phenols such as phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, phenols such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F and / or α-naphthol, β-naphthol. Epoxide of novolak resin obtained by condensation or cocondensation of naphthols such as dihydroxynaphthalene and aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde, etc. under an acidic catalyst, bisphenol A, bisphenol AD Epoxidizing bisphenol F, bisphenol S, diglycidyl ethers such as alkyl-substituted or unsubstituted biphenol, and phenol-aralkyl resins Epoxidized adducts or polyadducts of phenols with dicyclopentadiene or terpenes, glycidyl ester type epoxy resins obtained by the reaction of polybasic acids such as phthalic acid and dimer acid with epichlorohydrin, diamino Examples include glycidylamine type epoxy resins obtained by reaction of polyamines such as diphenylmethane and isocyanuric acid with epichlorohydrin, linear aliphatic epoxy resins obtained by oxidizing olefinic bonds with peracids such as peracetic acid, and alicyclic epoxy resins. Any number of these can be used in combination. Among them, biphenyl type epoxy resin, bisphenol F type epoxy resin, stilbene type epoxy resin and sulfur atom-containing epoxy resin are preferable from the viewpoint of fluidity and reflow resistance, and novolac type epoxy resin is preferable from the viewpoint of curability, From the viewpoint of low hygroscopicity, dicyclopentadiene type epoxy resin is preferable. From the viewpoint of heat resistance and low warpage, naphthalene type epoxy resin and triphenylmethane type epoxy resin are preferable. From the viewpoint of flame retardancy, biphenylene type epoxy resin is preferable. Resins and naphthol / aralkyl epoxy resins are preferred. It is preferable to contain at least one of these epoxy resins.

  The purity of the epoxy resin of component (A), especially the amount of hydrolyzable chlorine, is better because it relates to corrosion of aluminum wiring on the IC and other elements. In order to obtain it, it is preferable that it is 500 ppm or less. Here, the amount of hydrolyzable chlorine is a value obtained by dissolving 1 g of an epoxy resin of a sample in 30 ml of dioxane, adding 5 ml of a 1N-KOH methanol solution and refluxing for 30 minutes, and then obtaining by potentiometric titration. is there.

  The (B) curing agent of the present invention is not particularly limited. For example, it is generally used in an epoxy resin molding material for sealing electronic parts, such as phenol, cresol, resorcin, catechol, bisphenol A, bisphenol F and the like. Resins obtained by condensation or cocondensation of phenols or naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene and the like and aldehydes such as formaldehyde under an acidic catalyst, phenol / aralkyl resins, naphthol / aralkyl resins, etc. Yes, it can be used alone or in combination. Among them, a phenol / aralkyl resin is preferable from the viewpoint of improving reflow resistance. These curing agents can be used alone or in combination of two or more.

  The (C) curing accelerator of the present invention is not particularly limited. For example, 1,8-diaza-bicyclo (5,4,0) undecene-7, 1,5-diaza-bicyclo (4,3,0) ) Nonene, tertiary class such as 5,6-dibutylamino-1,8-diaza-bicyclo (5,4,0) undecene-7, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol Amines and their derivatives, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole and their derivatives, tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine Organic phosphines such as these and their phosphines Phosphorus compounds having intramolecular polarization formed by adding a compound having a π bond such as maleic anhydride, benzoquinone, diazophenylmethane, tetraphenylphosphonium tetraphenylborate, triphenylphosphinetetraphenylborate, 2-ethyl-4-methyl Imidazoletetraphenylborate, N-methylmotetraphenylphosphonium-tetraphenylborate, triphenylphosphine, adduct of triphenylphosphine and benzoquinone, adduct of triparatolyphosphine and benzoquinone, 1,8-diazabicyclo (5, 4,0) -undecene-7,2-phenyl-4methyl-imidazole, triphenylphosphonium-triphenylborane, and the like, which can be used alone or in combination.

  Moreover, as a filler, it is necessary to use (D) inorganic filler from a viewpoint of hygroscopic reduction and strength improvement. Examples of inorganic fillers include fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, boron nitride, beryllia, zirconia, or spherical beads of these, potassium titanate, silicon carbide One or more kinds of single crystal fibers such as silicon nitride and alumina, glass fibers, and the like can be blended. Furthermore, examples of the inorganic filler having a flame retardant effect include aluminum hydroxide and zinc borate, and these can be used alone or in combination.

  The blending amount of the inorganic filler is preferably 70% by weight or more from the viewpoints of hygroscopicity, reduction of linear expansion coefficient, strength improvement, and solder heat resistance. In particular, in order to solve the problems of the present invention, the average particle size of the inorganic filler is 13 μm or less. When the particle diameter is 13 μm or less, segregation of the inorganic filler is avoided during the molding of WBGA, and the effect of improving the laser mark property is sufficiently obtained.

  Among the above inorganic fillers, fused silica is preferable from the viewpoint of reducing the linear expansion coefficient, and alumina is preferable from the viewpoint of high thermal conductivity, and the filler shape is spherical from the viewpoint of fluidity and mold wear during molding. Is preferred.

  Other additives include coupling agents, mold release agents, colorants (carbon black, azo dyes, etc.), modifiers (silicone, silicone rubber, etc.), ion trappers (hydrotalcite, antimony-bismuth, if necessary) Based hydrous oxides).

  There is no restriction | limiting in particular about a coupling agent, You may use a conventionally well-known coupling agent together with a silane coupling agent. For example, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyl Trimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ- [bis (β-hydroxyethyl)] aminopropyltriethoxysilane, N-β- (aminoethyl) -Γ-aminopropyltrimethoxysilane, γ- (β-aminoethyl) aminopropyldimethoxymethylsilane, N- (trimethoxysilylpropyl) ethylenediamine, N- (dimethoxymethylsilylisopropyl) ethylenediamine, Tiltrimethoxysilane, methyltriethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, γ-anilinopropyltrimethoxy Silane coupling agents such as silane, vinyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, or isopropyltriisostearoyl titanate, isopropyltris (dioctylpyrophosphate) titanate, isopropyltri (N-aminoethyl-aminoethyl) titanate Tetraoctyl bis (ditridecyl phosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, bis (dio Tylpyrophosphate) oxyacetate titanate, bis (dioctylpyrophosphate) ethylene titanate, isopropyltrioctanoyl titanate, isopropyldimethacrylisostearoyl titanate, isopropyltridodecylbenzenesulfonyl titanate, isopropylisostearoyl diacryl titanate, isopropyltri (dioctylphosphate) One or more titanate coupling agents such as titanate, isopropyl tricumylphenyl titanate, and tetraisopropyl bis (dioctyl phosphite) titanate can be used in combination. Of these, a silane coupling agent having a secondary amino group is preferred from the viewpoint of fluidity and flame retardancy.

  Further, from the viewpoint of flame retardancy, various flame retardants may be further added. The flame retardant is generally used for the epoxy resin molding material for sealing and is not particularly limited. For example, a brominated epoxy resin such as a diglycidyl etherified product of tetrabromobisphenol A or a brominated phenol novolac epoxy resin. Phosphorus compounds such as antimony oxide, red phosphorus and phosphate esters, nitrogen-containing compounds such as melamine, melamine cyanurate, melamine-modified phenol resin and guanamine-modified phenol resin, phosphorus / nitrogen-containing compounds such as cyclophosphazene, zinc oxide, iron oxide , Molybdenum oxide, ferrocene, metal compounds such as aluminum hydroxide, magnesium hydroxide and composite metal hydroxides.

  As a general method for producing a molding material using the raw materials as described above, a raw material mixture of a predetermined blending amount is sufficiently mixed by a mixer or the like, then kneaded by a hot roll, an extruder, etc., cooled, pulverized, By doing so, a molding material can be obtained.

  As a method for sealing an electronic component using the epoxy resin composition obtained in the present invention, a low-pressure transfer molding method is the most common, but it can also be performed by a method such as injection molding, compression molding, or casting. .

  The epoxy resin composition produced by using the above means is excellent in laser markability, moldability and reliability in WBGA, and can be suitably used for sealing ICs, LSIs and the like.

Examples of the present invention will be described below, but the present invention is not limited thereto.
(Examples 1-2, Comparative Examples 1-3)
First, as shown in Table 1, inorganic fillers (fused silica) with different average particle diameters are prepared, pre-mixed (dry blended) with various materials, and then biaxial rolls (roll surface temperature of about 80 ° C.) And kneading for 10 minutes, cooling and pulverizing. The average particle size of the inorganic filler (fused silica) was measured with LA920 manufactured by HORIBA.

The raw materials listed in Table 1 are as follows.
Orthocresol novolac type epoxy resin: ESCN-190 manufactured by Sumitomo Chemical
Biphenyl type epoxy resin: YX-4000 made by Japan Epoxy
Phenol aralkyl resin: MEH-7800 made by Meiwa Kasei
Epoxy silane: Nippon Unicar Co., Ltd. trade name A-187
Carnauba wax: Noda Chemical's Carnauba Wax No. 1
Carbon black: MA600 manufactured by Mitsubishi Chemical

  Using this sealing material, each test was performed using a transfer molding machine under conditions of a mold temperature of 180 ° C., a molding pressure of 6.9 MPa, and a curing time of 90 seconds. Spiral flow was measured by EMM11-66. The hot hardness was measured with a shear hardness meter.

  In addition, using this encapsulant, a semiconductor element is molded under the same conditions with a transfer molding machine, post-curing (175 ° C./6 h), solder heat resistance, segregation of inorganic filler due to ultrasonic flaw detection, and laser mark property. evaluated.

  The semiconductor device used for solder heat resistance is a WBGA resin-encapsulated semiconductor device having a chip size of 8.8 × 8.8 mm in a package size of 12 × 12 mm.

  For the resin-encapsulated semiconductor device thus obtained, the resin when the solder heat resistance is baked at 125 ° C./24 h and then absorbed at 85 ° C./85 RH% / 168 h for 260 ° C./10 sec. The determination was made based on the occurrence of peeling and the crack generation rate of the sealed semiconductor device.

  For the evaluation of segregation of the inorganic filler by ultrasonic flaw detection, the presence or absence of segregation was confirmed by observing with an ultrasonic flaw detector using a molded WBGA resin-sealed semiconductor device.

For the laser mark property, the package surface of WBGA, PBGA, TSOP, SOP, QFP, LQFP, and DIP was printed with a YAG laser marking device, and the mark property was visually evaluated.
The conditions of the above YAG laser are shown below.
YAG laser wavelength: 1064 nm
Laser power: 5J
The test results are summarized in Table 2.

  As shown in Examples 1 and 2, the WBGA does not cause segregation of the inorganic filler, and as a result, a sealing material excellent in laser mark property and a semiconductor device using the same can be obtained.

It is sectional drawing which shows the structure of WBGA. It is a top view which shows the flow of the sealing resin inside a package. It is sectional drawing which shows the flow of the sealing resin inside a package.

Claims (3)

  (A) an epoxy resin, (B) a curing agent, (C) a curing accelerator, (D) an inorganic filler, and (D) an average particle size of the inorganic filler is 13 μm or less. Resin composition.   (D) The compounding quantity of an inorganic filler is 70 weight% or more, The epoxy resin composition of Claim 1 characterized by the above-mentioned.   A resin-encapsulated semiconductor device having a package form of WBGA (window ball grid array) obtained by encapsulating a semiconductor element using the epoxy resin composition according to claim 1.

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