JP3262120B2 - Epoxy resin molding material for sealing electronic parts and IC package - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an epoxy resin molding material for electronic component sealing suitable for a C package, and an IC package in which an electronic component is sealed with the epoxy resin molding material.

[0002]

2. Description of the Related Art Epoxy resin molding materials have been widely used in the field of sealing electronic components such as transistors and ICs. The reason for this is that the epoxy resin is balanced in various properties such as electrical properties, moisture resistance, heat resistance, mechanical properties, and adhesiveness to an insert product. In particular, the combination of an ortho-cresol novolak type epoxy resin, a resin and a phenol novolak curing agent has an excellent balance between them, and has become mainstream as a base resin of a molding material for IC encapsulation.

[0003]

In recent years, high-density mounting of electronic components on printed wiring boards has been progressing. Along with this, the electronic component has become the mainstream from the conventional pin insertion type package to the surface mount type package. IC, LS
Surface mount type IC packages such as I have a thin and small package to increase the packaging density and reduce the mounting height. It's getting thinner. Furthermore, these packages are different in mounting method from the conventional pin insertion type. That is, in the pin insertion type package, the pins are inserted into the wiring board and then soldered from the back surface of the wiring board, so that the package is not directly exposed to a high temperature. However, since the surface mount type IC package is temporarily fixed to the surface of the wiring board and processed by a solder bath or a reflow device, it is directly exposed to a soldering temperature. As a result, when the IC package absorbs moisture, the moisture absorbs rapidly expands at the time of soldering, and the package is cracked. At present, this phenomenon is a major problem related to the surface mount type IC package.

[0004] In the case of an IC package sealed with a current base resin composition, the above problems cannot be avoided. Therefore, the IC package is shipped in a moisture-proof package before being mounted on a wiring board.
Are used after being sufficiently dried. However, these methods are laborious and costly.

The present invention has been made in view of such circumstances, and has an epoxy resin molding material for sealing electronic components, which can be soldered without a specific pretreatment when mounting on a wiring board. Thus, an IC package in which an electronic component is sealed is provided.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have formulated a specific epoxy resin having a biphenyl skeleton as a base resin, and have a naphthalene ring in the skeleton. The present inventors have found that the above object can be achieved by using the compound in combination with a compound having not less than% by weight, and have completed the present invention.

That is, the present invention provides (1) (A) an epoxy resin represented by the following general formula (I), and (B) aldehydes of naphthols and phenols.
-Based co-condensation resin, and naphtho having xylylene group
Aralkyl resin, a compound containing at least 20% by weight of a naphthalene ring in a skeleton and having two or more phenolic hydroxyl groups in one molecule (however, represented by the following general formula (II)) And (C) an inorganic filler as an essential component, and the blending amount of the (C) inorganic filler is 60% by volume with respect to the epoxy resin molding material for encapsulating electronic parts.
Epoxy resin molding material for electronic component sealing,

Embedded image

Embedded image (Wherein, l represents an integer of 0 to 5.) (2) electronic component encapsulating epoxy resin molding material according to the softening point of the compound (B) is 100 ° C. or higher (1), ( 3) (after pre-heated mixture of a compound of epoxy resin and (B) in a), a characterized by producing by performing adding, mixing other ingredients of the inorganic filler (C) and its using the above (1) or (2) electronic component encapsulating epoxy resin molding material described in, and (4) above (1) for electronic component encapsulation epoxy resin molding material according to any one of the - (3) And (5) (A) an epoxy resin represented by the general formula (I).
And (B) aldehydes of naphthols and phenols
-Based co-condensation resin, and naphtho having xylylene group
Aralkyl resin, and
Containing at least 20% by weight of phthalene rings and two per molecule
Compounds having the above phenolic hydroxyl group (however,
Excluding the compound represented by the general formula (II))
After heating and mixing, (C) inorganic filler and other composition
Electronic components sealed by adding and kneading
The present invention relates to a method for producing an epoxy resin molding material for use .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin (A) in the present invention has a biphenyl skeleton in the skeleton represented by the following general formula (I), and the purity of the epoxy resin, especially the amount of hydrolyzable chlorine is determined by IC For example, the amount is preferably less than 500 ppm in order to obtain an epoxy resin molding material for sealing electronic components having excellent moisture resistance, but it is not particularly limited. Here, the amount of hydrolyzable chlorine means that 1 g of a sample epoxy resin was dissolved in 30 ml of dioxane, 5 ml of a 1N-KOH methanol solution was added, and after refluxing for 30 minutes,
The value obtained by potentiometric titration is used as a scale.
The epoxy resin (A) can be obtained by epoxidizing 4,4′-bishydroxy 3,3 ′, 5,5-tetramethylbiphenyl using shrimp chlorohydrin.

Embedded image

The epoxy resin used in the present invention includes, in addition to (A) the epoxy resin represented by the general formula (I), other epoxy resins generally used in epoxy resin molding materials for sealing electronic parts. Resins may be used in combination. In the present invention, examples of other epoxy resins that can be used in combination with the epoxy resin (A) represented by the general formula (I) include phenols such as phenol novolak epoxy resins and orthocresol novolak epoxy resins. Epoxidized novolak resins of aldehydes, glycidyl ester type epoxy resins obtained by the reaction of epichlorohydrin with polybasic acids such as diglycidyl ethers such as bisphenol A, bisphenol B, phenol F and bisphenol S, phthalic acid and dimer acid Glycidylamine-type epoxy resins obtained by the reaction of epichlorohydrin with polyamines such as diaminodiphenylmethane and isocyanuric acid; linear aliphatic compounds obtained by oxidizing olefin bonds with peracids such as peracetic acid Epoxy resins, include an alicyclic epoxy resin, it can be used together even these at an appropriate number of types.

When these epoxy resins are used in combination, there is no particular limitation on the (A) general formula (I) of the present invention.
Is preferably 30% by weight or more, more preferably 50% by weight or more of the entire epoxy resin. The reason for this is that less than 30% by weight has little effect on the reflow resistance, which is the object of the present invention,
This is because 50% by weight or more is required to exhibit a particularly effective effect.

The compound (B) used in the present invention includes naphthols and aldehydes of phenols
-Based co-condensation resin, and naphtho having xylylene group
Aralkyl resin, which is a compound containing at least 20% by weight of a naphthalene ring in a skeleton and having two or more phenolic hydroxyl groups in one molecule and represented by the following general formula (II) The compound may be a compound, and is not particularly limited . In here, the case of using a resin having a naphthalene ring in the skeleton, greatly influence the ratio of naphthalene ring on reflow resistance, in particular to exhibit the effect of the present invention are included in the compounds of (B) The proportion of naphthalene rings must be at least 20% by weight and not 100% .

Embedded image (Here, 1 represents an integer of 0 to 5.)

The epoxy resin (A) of the present invention is crystalline and therefore solid at room temperature by itself, but has a low viscosity when it is compatible with other compounds such as a curing agent. Are likely to be in a semi-solid state or easily blocked. Therefore, in order to avoid such inconvenience, it is preferable to use the compound (B) having a high softening point. In this case, the softening point is preferably 100 ° C. or higher. However, if the softening point is too high, the fluidity at the time of molding is hindered. Therefore, the upper limit is preferably 150 ° C. or lower. Further, when the compound (B) having a high softening point and the epoxy resin (A) are mixed and kneaded, a uniform molding material is difficult to obtain because the viscosities of both resin systems are greatly different in a kneading apparatus. . Therefore, although not particularly limited, after the epoxy resin of (A) and the compound of (B) are mixed in advance by heating,
(C) It is preferable to manufacture by adding other compounding components such as an inorganic filler and a curing accelerator and kneading. The heating and mixing conditions are preferably 80 ° C. or higher at which the viscosity of the epoxy resin (A) is sufficiently low and 140 ° C. or lower at which the reaction between the epoxy group and the phenol group is relatively mild. , And (B) are preferably the minimum necessary to uniformly dissolve the resins.

In the present invention, in addition to the component (B), other compounds having two or more phenolic hydroxyl groups in one molecule (phenolic resins) can be used in combination. Here, other phenol resins that can be used in combination are those generally used in epoxy resin molding materials for electronic component encapsulation and are not particularly limited. For example, phenol, cresol, xylenol, resorcin, catechol, bisphenol A Phenolic resins such as bisphenol F and aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde and salicylaldehyde in the presence of an acidic catalyst in a novolak-type phenolic resin, polyparavinylphenol resin and the like. One type may be used alone, or two or more types may be used in combination as long as the effects of the present invention can be obtained.

The equivalent ratio of the epoxy resin containing the component (A) and the compound having a phenolic hydroxyl group containing the component (B) used in the present invention is not particularly limited, but it is preferable from the viewpoints of curability and heat resistance. , 0.6 to 1.4.

Further, the epoxy resin molding material for encapsulating electronic parts of the present invention can use a curing accelerator for accelerating the curing reaction between the epoxy resin and the compound having a phenolic hydroxyl group. As the curing accelerator, for example,
1,8-diazabicyclo (5,4,0) undecene-
7, triethylenediamine, benzyldimethylamine,
Tertiary amines such as triethanolamine, dimethylaminoethanol and tris (dimethylaminomethyl) phenol; imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole and the like , Organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, phenylphosphine and phenylphosphine; tetraphenylphosphonium / tetraphenylborate, tetraphenylphosphonium / ethyltriphenylborate and tetrabutylphosphonium / rate Substituted phosphonium tetra-substituted borate, 2-ethyl-4-methylimidazole
And tetraphenylboron salts such as tetraphenylborate and N-methylmorpholine / tetraphenylborate. Here, as a result of intensive studies on cracks during reflow, which is the object of the present invention, it was found that 1,8-diaza-bicyclo (5,4,0) undecene-7, its phenol derivative or tetra-substituted phosphonium-tetra-substituted compound. It has been found that the use of borates as a curing accelerator is particularly effective. Further, as the tetra-substituted phosphonium / tetra-substituted borate, tetraphenyl phosphonium / tetraphenyl borate is preferable. The reason for this is that the effect of the curing accelerator on the properties of the cured product is so great that 1,8-diaza-bicyclo (5,4,
0) When undecene-7, its phenol derivative or tetra-substituted phosphonium / tetra-substituted borate is used, Tg (glass transition temperature), which is an index of heat resistance, is relatively high and the water absorption is small, so that it is constant. It can be inferred that cracks did not occur even when soldering the IC package that was humidified for a long time. Therefore, in order to effectively exhibit the effects of the resin system of the present invention, a combination with the above-mentioned curing accelerator is preferable, but not particularly limited.

In the epoxy resin molding material for encapsulating electronic parts of the present invention, it is necessary to use (C) an inorganic filler as a filler from the viewpoint of reducing hygroscopicity and improving strength. (C) The inorganic filler is not particularly limited. For example, crystalline silica, fused silica, alumina, zircon,
Powders of calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, etc., or spherical beads thereof, etc. They may be used alone or in combination of two or more. (C) For the same reason, the blending amount of the inorganic filler is required to be 60% by volume or more based on the epoxy resin molding material for sealing electronic parts, and further, 65% by volume.
The above is preferred.

The epoxy resin molding material for encapsulating electronic parts of the present invention contains, as other additives, release agents such as higher fatty acids, metal salts of higher fatty acids, ester waxes, coloring agents such as carbon black, epoxyquinosilane, aminosilane. ,
Coupling agents such as ureido silane, vinyl silane, alkyl silane, organic titanate, aluminum alcohol and the like, flame retardants and the like can be used as required.

As a general method for producing an epoxy resin molding material for electronic component encapsulation using the above-mentioned raw materials, a raw material having a predetermined compounding amount is sufficiently mixed by a mixer or the like, and then mixed with a mixing roll, an extruder. The molding material can be obtained by kneading, cooling, and pulverizing by the method described above.

As a method for sealing an electronic component using the epoxy resin molding material for sealing an electronic component obtained by the present invention, a low-pressure transfer molding method is most commonly used.
Injection molding and compression molding are also possible. The IC package in which the electronic component is encapsulated with the epoxy resin molding material for encapsulating the electronic component of the present invention is not particularly limited, and supports a lead frame, a wired tape carrier, a wiring board, glass, a silicon wafer, and the like. Electronic components, such as active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils, are mounted on members, and transfer molding is performed using epoxy resin molding materials for electronic component sealing. A typical IC package or the like formed by sealing is used.

[0020]

The damage to the IC package during reflow is caused by the rapid expansion of the moisture absorbed during storage of the IC during reflow, which results in cracks in the package and separation of the interface between the element and the lead frame and the resin. . Therefore, a resin that is resistant to reflow is required to have a low water absorption, a high strength at a high temperature, and a high adhesive strength. The epoxy resin that is the main component of the present invention is a diepoxy resin based on tetramethylbiphenol, and the curing agent has a naphthalene ring in the skeleton.
It can be inferred that a composition having excellent moisture absorption properties and adhesiveness could be obtained. It is considered that the reflow crack resistance was improved by this effect.

[0021]

EXAMPLES The present invention will be described below with reference to examples, but the scope of the present invention is not limited to these examples.

Examples 1-3, Comparative Examples 1-2 Epoxy resins represented by the following general formula (I)

Embedded image An epoxy resin 80 having an epoxy equivalent of 188 and containing as a main component
Parts by weight and the following general formula (III)

Embedded image (N: m = 35: 65, weight average molecular weight 750) A hydroxyl group equivalent of 127, a softening point of 110 ° C and a β-naphthol / phenol cocondensation novolak resin (59 parts by weight)
The mixture was melt-mixed at 30 ° C. for 30 minutes, and the solid resin obtained after cooling was mixed with a bromine ratio of 50% by weight and an epoxy equivalent of 37.
5, 20 parts by weight of a brominated bisphenol A type epoxy resin, 1,8-diazabicyclo (5,4,0) undecene-7 (3 parts by weight), carnauba wax (2 parts by weight), carbon black (1 part by weight), γ-glycidoxypropyltrimethoxysilane (2 parts by weight), quartz glass powder (7
5% by weight), and a 10-inch diameter heating roll was used to produce the epoxy resin molding material of Example 1 at a kneading temperature of 80 to 90 ° C. and a kneading time of 7 to 10 minutes.

Example 2 The β-naphthol / phenol co-condensed novolak resin of Example 1 was converted to a phenol resin represented by the following general formula (IV).

Embedded image The epoxy resin molding material of Example 2 was produced in the same manner as in Example 1, except that the resin was replaced with 65 parts by weight of a resin having a hydroxyl equivalent of 140 and a softening point of 115 ° C.

Example 3 The β-naphthol / phenol co-condensed novolak resin of Example 1 was converted to the following general formula (V)

Embedded image Resin 1 having a hydroxyl equivalent of 220 and a softening point of 108 ° C.
An epoxy resin molding material of Example 3 was produced in the same manner as in Example 1 except that the composition was replaced with 02 parts by weight.

Comparative Example 1 In place of the β-naphthol / phenol co-condensed novolak resin of Example 1, the hydroxyl equivalent was 106 and the weight average molecular weight was 66.
An epoxy resin molding material of Comparative Example 1 was produced in the same manner as in Example 1 except that 63 parts by weight of a phenol novolak resin having a softening point of 85 ° C. was used as a base resin without previously melting and mixing.

Comparative Example 2 Comparative Example 2 was repeated in the same manner as in Comparative Example 1 except that the biphenyl skeleton diepoxy resin of Comparative Example 1 was replaced with 80 parts by weight of an orthocresol novolac type epoxy resin having an epoxy equivalent of 200 and a softening point of 73 ° C. An epoxy resin molding material was produced.

Table 1 shows the characteristics of Examples 1 to 3 and Comparative Examples 1 and 2, and Table 2 shows details of the test method. It can be seen that the examples have a smaller water absorption and are superior in adhesive strength as compared with the comparative examples.

[0028]

[Table 1]

[0029]

[Table 2]

In order to clarify the effects of the present invention, Table 3 shows the results of crack resistance during reflow and moisture resistance after reflow using the IC package for evaluation. The external shape of the IC package used for the evaluation of crack resistance was 19 × 14 × 2.
0 (mm) flat package, 8 × 10 ×
This is an 80-pin, 42-alloy lead mounted with a 0.4 (mm) element. The test conditions were as follows: after humidification at 85 ° C. and 85% RH for a predetermined time, heating was performed in a vapor phase reflow furnace at 215 ° C. for 90 seconds. The evaluation was performed by observing the appearance under a microscope and determining the presence or absence of a package crack. The IC package used for the evaluation of moisture resistance was a small outline package of 350 mil width and 28 pins, and was provided with aluminum wiring of 10 μm width.
Equipped with × 10 × 0.4 (mm) test element, 25μm
The wire bonding is performed using the gold wire of FIG. The test conditions were humidification at 85 ° C. and 85% RH for 72 hours, followed by 215
After heating in a vapor phase reflow furnace at 90 ° C for 90 seconds,
The test was conducted by humidifying under the conditions of 2 atm, 121 ° C., and 100% RH for a predetermined period of time, and examined for disconnection failure due to corrosion of aluminum wiring. The IC package was molded at 180 ° C for 90 seconds.
The molding was performed under the conditions of 70 kgf / cm ² (6.9 MPa), and post-curing was performed at 180 ° C. for 5 hours after molding.

[0031]

[Table 3]

As shown in Examples 1 to 3 in Table 3, by using the epoxy resin (A) of the present invention and the compound (B), the resistance to reflow during the reflow process was higher than that of the conventional resin system of the comparative example. Cracking properties and moisture resistance after reflow can be significantly improved.

[0033]

The epoxy resin molding material for encapsulating electronic parts according to the present invention can significantly improve crack resistance during reflow and moisture resistance after reflow as compared with the conventional one. Electronic components, especially FP (flat package), SOP
In an IC package such as a (small outline package), the package becomes thinner and smaller, and the package crack resistance is strongly required in combination with the increase in the size of the element. Since resin molding materials can be widely applied to these products, their industrial value is great.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-218735 (JP, A) JP-A-2-91966 (JP, A) JP-A-2-91965 (JP, A) JP-A-1- 268711 (JP, A) JP-A-64-87616 (JP, A) JP-A-62-167318 (JP, A) JP-A-4-173829 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 59/62 C08L 3/00 C08L 63/00-63/10 H01L 23/29

Claims (5)

(57) [Claims] 1. Use of (A) an epoxy resin represented by the following general formula (I), and (B) aldehydes of naphthols and phenols.
Co-condensation resin and naphthol having xylylene group
A aralkyl resin, a compound containing at least 20% by weight of a naphthalene ring in a skeleton and having two or more phenolic hydroxyl groups in one molecule (however, a compound represented by the following general formula (II)) And (C) an inorganic filler as an essential component, and (C) an epoxy resin for electronic component encapsulation wherein the blending amount of the inorganic filler is 60% by volume or more based on the epoxy resin molding material for electronic component encapsulation. Molding material. Embedded image Embedded image (Here, 1 represents an integer of 0 to 5.) 2. The epoxy resin molding material for sealing electronic parts according to claim 1, wherein the compound (B) has a softening point of 100 ° C. or higher. 3. After pre-heated mixture of a compound of epoxy resin and (B) of (A), was added <br/> other ingredients of the inorganic filler (C) and its, by performing the kneading The epoxy resin molding material for electronic component sealing according to claim 1 or 2, which is manufactured. 4. An IC package in which an electronic component is sealed using the epoxy resin molding material for sealing electronic components according to claim 1. 5. An epoxy resin represented by the general formula (I):
Resin and (B) Using naphthols and aldehydes of phenols
Co-condensation resin and naphthol having xylylene group
・ Any of aralkyl resins, naphtha in the skeleton
Contains at least 20% by weight of a ren ring, and two or more per molecule
Compounds having a phenolic hydroxyl group of
Excluding the compound represented by formula (II))
After mixing, (C) inorganic filler and other compounding ingredients
Adding and kneading the mixture.
Manufacturing method of epoxy resin molding material.