JP3966289B2 - Epoxy resin molding material for electronic component sealing and electronic component - Google Patents

Description

  The present invention is an epoxy resin molding material for semiconductor encapsulation, particularly an epoxy resin molding material for non-halogen electronic components that is required from the viewpoint of environmental friendliness, and is required to have strict reliability such as moisture resistance and reflow crack resistance. The present invention relates to a molding material suitable for sealing VLSI and an electronic component in which an element is sealed with the molding material.

  Conventionally, epoxy resin molding materials have been widely used in the field of sealing electronic device elements such as transistors and ICs. This is because epoxy resins are balanced in various properties such as electrical properties, moisture resistance, heat resistance, mechanical properties, and adhesiveness with inserts. The flame retardant of these epoxy resin molding materials is mainly performed by a combination of a brominated resin such as dibromocidyl ether of tetrabromobisphenol A and antimony oxide.

In recent years, the problem of dioxins originated from the viewpoint of environmental protection, and there is a movement of regulation for halogenated resins including decabromo. Similarly, antimony compounds are also being regulated from the viewpoint of toxicity, and there is a demand for dehalogenation (debromination) and deantimony formation for epoxy resin molding materials for electronic component sealing. In addition, it is known that bromo ions have an adverse effect on the high-temperature standing characteristics of plastic-encapsulated ICs, and from this viewpoint, it is desired to reduce the amount of brominated resin.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide an epoxy resin material for encapsulating electronic components having excellent high-temperature storage characteristics.

  As a result of intensive studies in order to solve the above problems, the inventors have found that the above object can be achieved by blending a specific flame retardant, and the present invention has been completed.

（ｎは３〜５の整数で、Ｒ、Ｒ’は同じでも異なっていてもよい炭素数１〜４のアルキル基またはアリール基を示す。）
（Ｄ）無機充填剤、
を必須成分とする成形材料であって、（Ｃ）成分の含有量は充填剤（Ｄ）を除く配合成分の合計量に対して燐原子の量が０．２〜３．０重量％となる量であり、（Ｄ）成分の含有量が成形材料全体に対して７０重量％以上で、（Ｄ）無機充填剤に難燃効果のある無機充填剤を含む電子部品封止用エポキシ樹脂成形材料、
（２）（Ｄ）無機充填剤に水酸化アルミニウム、水酸化マグネシウム、硼酸亜鉛から選ばれる１種類以上を含む上記（１）記載の電子部品封止用エポキシ樹脂成形材料、
（３）（Ｃ）成分のｎ個のＲ及びｎ個のＲ’が全てフェニル基である上記（１）または（２）記載の電子部品封止用エポキシ樹脂成形材料、
（４）（Ｃ）成分のｎ個のＲとｎ個のＲ’のうち２〜４個がヒドロキシフェニル基であり、他の全てがフェニル基である上記（１）または（２）記載の電子部品封止用エポキシ樹脂成形材料、
（５）（Ｃ）成分のｎ個のＲ及びｎ個のＲ’が全てヒドロキシフェニル基である上記（１）または（２）記載の電子部品封止用エポキシ樹脂成形材料、
（６）（Ａ）成分のエポキシ樹脂が４，４’−ビス（２，３−エポキシプロポキシ）−３，３’，５，５’−テトラメチルビフェニル、
フェノール類とアルデヒド類のノボラック樹脂をエポキシ化したもの、
ビスフェノールＡ、ビスフェノールＦ、ビスフェノールＳ、アルキル置換ビフェノールのジグリシジルエーテル、
グリシジルアミン型エポキシ樹脂、
線状脂肪族エポキシ樹脂及び
脂環族エポキシ樹脂の何れかを少なくとも含む上記（１）〜（５）記載のいずれかの電子部品封止用エポキシ樹脂成形材料、
（７）（Ｂ）成分が、フェノール類又はナフトール類とアルデヒド類とを酸性触媒下で縮合又は共縮合させて得られる樹脂、
ポリパラビニルフェノール樹脂、
フェノール類とジメトキシパラキシレンから合成されるキシリレン基を有するフェノール・アラルキル樹脂
の何れかを少なくとも含む上記（１）〜（６）記載のいずれかの電子部品封止用エポキシ樹脂成形材料、
（８）更にカップリング剤を含む上記（１）〜（７）記載のいずれかの電子部品封止用エポキシ樹脂成形材料、
（９）（Ｃ）成分のｎが３である上記（１）〜（８）記載のいずれかの電子部品封止用エポキシ樹脂成形材料、
（１０）上記（１）〜（９）記載のいずれかの電子部品封止用エポキシ樹脂成形材料により素子を封止して得られる電子部品、
である。 That is, the present invention
(1) (A) an epoxy resin having two or more epoxy groups in one molecule;
(B) a compound having two or more phenolic hydroxyl groups in one molecule;
(C) a cyclic phosphazene compound represented by the following formula (I):

(N is an integer of 3 to 5, and R and R ′ represent the same or different alkyl group or aryl group having 1 to 4 carbon atoms.)
(D) inorganic filler,
In which the content of the component (C) is such that the amount of phosphorus atoms is 0.2 to 3.0% by weight with respect to the total amount of the blending components excluding the filler (D). An epoxy resin molding material for sealing electronic components, which contains an inorganic filler having a flame retardant effect in the inorganic filler, wherein the content of the component (D) is 70% by weight or more with respect to the whole molding material ,
(2) (D) The epoxy resin molding material for electronic component sealing according to (1), wherein the inorganic filler contains one or more selected from aluminum hydroxide, magnesium hydroxide, and zinc borate,
(3) The epoxy resin molding material for sealing an electronic component according to the above (1) or (2), wherein n R and n R ′ of the component (C) are all phenyl groups,
(4) The electron according to the above (1) or (2), wherein 2 to 4 of n R and n R ′ of the component (C) are hydroxyphenyl groups and all the others are phenyl groups Epoxy resin molding material for component sealing,
(5) The epoxy resin molding material for sealing electronic parts according to the above (1) or (2), wherein n R and n R ′ in the component (C) are all hydroxyphenyl groups,
(6) The epoxy resin of component (A) is 4,4′-bis (2,3-epoxypropoxy) -3,3 ′, 5,5′-tetramethylbiphenyl,
Epoxidized phenol and aldehyde novolak resins,
Bisphenol A, bisphenol F, bisphenol S, diglycidyl ether of alkyl-substituted biphenol,
Glycidylamine type epoxy resin,
The epoxy resin molding material for sealing an electronic component according to any one of the above (1) to (5), comprising at least one of a linear aliphatic epoxy resin and an alicyclic epoxy resin,
(7) (B) component is a resin obtained by condensation or cocondensation of phenols or naphthols and aldehydes under an acidic catalyst,
Polyparavinylphenol resin,
An epoxy resin molding material for sealing an electronic component according to any one of (1) to (6) above, comprising at least one of a phenol / aralkyl resin having a xylylene group synthesized from phenols and dimethoxyparaxylene,
(8) The epoxy resin molding material for electronic component sealing according to any one of (1) to (7), further including a coupling agent,
(9) The epoxy resin molding material for sealing an electronic component according to any one of (1) to (8), wherein n of component (C) is 3.
(10) An electronic component obtained by sealing an element with the epoxy resin molding material for sealing an electronic component according to any one of (1) to (9) above,
It is.

  The epoxy resin molding material for sealing electronic parts obtained by the present invention can achieve flame retardancy with non-halogen and non-antimony, and if this is used to seal electronic parts such as IC, LSI, the moldability is good, Products with excellent reliability such as moisture resistance and high temperature storage properties can be obtained, and their industrial value is great.

  The epoxy resin of the component (A) used in the present invention is not particularly limited as it is generally used in an epoxy resin molding material for encapsulating electronic parts. For example, phenol novolak type epoxy resin, orthocresol novolak type Reaction of epichlorhydrin with epoxidized novolak resin of phenols and aldehydes such as epoxy resin, diglycidyl ether such as bisphenol A, bisphenol F, bisphenol S, alkyl-substituted biphenol, diaminodiphenylmethane, isocyanuric acid and the like There are glycidylamine type epoxy resins obtained by oxidization, linear aliphatic epoxy resins obtained by oxidizing olefinic bonds with peracids such as peracetic acid, and alicyclic epoxy resins. It is possible to use.

  Among the epoxy resins shown above, when an alkyl-substituted biphenol type diepoxy resin such as 4,4′-bis (2,3-epoxypropoxy) -3,3 ′, 5,5′-tetramethylbiphenyl is used Adhesiveness and hygroscopicity are good, whereby a molding material having excellent reflow crack resistance and moisture resistance can be obtained. The alkyl-substituted biphenol type diepoxy resin is preferably used in an amount of 60% by weight or more based on the total amount of the epoxy resin. If it is less than 60% by weight, the low hygroscopicity and high adhesive properties of the epoxy resin are not exhibited, and the effect on the solder resistance which is the object of the present invention is small. Examples of the epoxy resin include those obtained by epoxidizing 4,4'-bishydroxy 3,3 ', 5,5'-tetramethylbiphenyl with epichlorohydrin.

  As the compound having two or more phenolic hydroxyl groups in one molecule of the component (B) used in the present invention, phenols such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, or α-naphthol , Resins obtained by condensation or cocondensation of naphthols such as β-naphthol and dihydroxynaphthalene with aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde and salicylaldehyde under an acidic catalyst, polyparavinylphenol resin, phenol Phenol and aralkyl resins having a xylylene group synthesized from dimethoxyparaxylene, and may be used alone or in combination of two or more.

  The equivalent ratio of the (A) component epoxy resin and the (B) component phenolic compound (number of hydroxyl groups in (B) / number of epoxy groups in (A)) is not particularly limited, but to keep each unreacted component small. It is preferable to set in the range of 0.7 to 1.3.

  Moreover, the hardening accelerator which accelerates | stimulates hardening reaction of an epoxy resin and a phenol resin can be used as needed. Examples of the curing accelerator include diazabicycloalkenes such as 1,8-diazabicyclo (5,4,0) undecene-7 and derivatives thereof, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris. Tertiary amines such as (dimethylaminomethyl) phenol, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, tributylphosphine, methyldiphenylphosphine, tri Organic phosphines such as phenylphosphine, tetrasubstituted phosphonium / tetrasubstituted borates such as tetraphenylphosphonium / tetraphenylborate, 2-ethyl-4-methylimidazole / tetraphenylborate Over bets, and the like tetraphenyl boron salts such as N- methylmorpholine tetraphenylborate.

（ｎは３〜５の整数で、Ｒ、Ｒ’は同じでも異なっていてもよい炭素数１〜４のアルキル基またはアリール基を示す。）で示される化合物で、３量体の６員環、４量体の８員環、５量体の１０員環を単独あるいは混合して用いることができる。エポキシ樹脂成形材料の流動性からは３量体を主成分として用いることが好ましい。 The cyclic phosphazene compound of component (C) used as a flame retardant in the present invention has the following formula (I)

(Wherein n is an integer of 3 to 5 and R and R ′ are the same or different and each represents an alkyl group or aryl group having 1 to 4 carbon atoms), and a trimer 6-membered ring A tetramer 8-membered ring or a pentamer 10-membered ring can be used alone or in combination. In view of the fluidity of the epoxy resin molding material, it is preferable to use a trimer as a main component.

  In the above formula (I), n R and R ′ may be the same or different and each is an alkyl group or aryl group having 1 to 4 carbon atoms. For example, when n is a trimeric 6-membered ring, R and R ′ are 6 substituents, which may all be the same or different. From the viewpoint of heat resistance and moisture resistance of the epoxy resin molding material, an aryl group is preferred. Particularly preferred is a phenyl group, and more preferred is a hydroxyphenyl group. When a hydroxyphenyl group is introduced, all of n R and n R ′ may be a hydroxyphenyl group, but 2 to 4 are preferably introduced. When the number of hydroxyphenyl groups is 5 or more, the cured epoxy resin is likely to be brittle, and when it is less than 2, a component that is not taken into the crosslinked structure of the epoxy resin appears, so that the heat resistance tends to decrease.

（Ｒ₁〜Ｒ₆のうち２〜４個は水酸基で、他の４〜２個は水素を示す。）などがあげられる。 Preferred structures of the cyclic phosphazene compound of component (C) used in the present invention include, for example, the following formulas (II) to (IV)

(2 to 4 of R _{1 to} R ₆ are hydroxyl groups, and the other 4 to 2 represent hydrogen).

  The addition amount of these cyclic phosphazene compounds needs to be within the range of 0.2 to 3.0% by weight of the phosphorus atom with respect to all other ingredients except the filler. If it is less than 0.2% by weight, the flame retardant effect is not exhibited, and if it exceeds 3.0% by weight, the moisture resistance is lowered.

  In the present invention, by using a specific cyclic phosphazene compound as the component (C), a non-halogen, non-antimony epoxy resin molding material for sealing flame-retardant electronic components having excellent reliability and moldability is provided. . Although it is generally known that the combined use of a phosphorus compound and a nitrogen compound is good for flame retardancy, the present invention provides a phosphorus atom as a flame retardant component of an epoxy resin molding material for semiconductor encapsulation that can exhibit excellent reliability. And a compound containing both nitrogen atoms in the structure.

  Moreover, as a filler, it is necessary to use an inorganic filler from a viewpoint of hygroscopic reduction and strength improvement. As the inorganic filler of the component (D) in the present invention, powders such as fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, boron nitride, beryllia, zirconia, or spheres thereof are used. One or more kinds of single crystal fibers such as beads, potassium titanate, silicon carbide, silicon nitride, and alumina, and glass fibers can be blended and used. Furthermore, examples of the inorganic filler having a flame retardant effect include aluminum hydroxide, magnesium hydroxide, zinc borate and the like, 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, and improvement of strength. 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 during molding and mold wear. Is preferred.

  Other additives include higher fatty acids, higher fatty acid metal salts, release agents such as ester wax and polyolefin wax, colorants such as carbon black, epoxy silane, amino silane, ureido silane, vinyl silane, alkyl silane, organic titanate, aluminum A coupling agent such as alcoholate can be used.

  The molding material in the present invention can be prepared by any method as long as various raw materials can be uniformly dispersed and mixed, but as a general method, after sufficiently mixing raw materials of a predetermined blending amount with a mixer or the like, A method of cooling and pulverizing after melt-kneading with a mixing roll, an extruder or the like can be mentioned.

Mounting elements such as semiconductor chips, transistors, diodes, thyristors and other active elements, capacitors, resistors, passive elements such as coils, etc. on support members such as lead frames, wired tape carriers, wiring boards, glass and silicon wafers And an electronic component can be manufactured by sealing a necessary part with the molding material for sealing of the present invention. As such an electronic component, for example, a TCP in which a semiconductor chip connected to a tape carrier by a bump is sealed with the molding material of the present invention can be cited. Also, active elements such as semiconductor chips, transistors, diodes, thyristors and / or passive elements such as capacitors, resistors, coils, etc. connected to wiring formed on wiring boards or glass by wire bonding, flip chip bonding, solder, etc. Can be mentioned COB modules, hybrid ICs, multichip modules and the like sealed with the molding material of the present invention.
As the method for sealing the electronic component, the low pressure transfer molding method is the most common, but an injection molding method, a compression molding method, or the like may be used.

  EXAMPLES Next, although an Example demonstrates this invention, the scope of the present invention is not limited to these Examples.

（Ｒ₁〜Ｒ₆のうち３個は水酸基で他の３個は水素を示す）、を表１に示す重量比で配合し、混練温度８０〜９０℃、混練時間１０分の条件でロール混練を行い、実施例１〜６の成形材料を作製した。 Examples 1-6
Cresol novolak type epoxy resin having an epoxy equivalent of 200 and a softening point of 67 ° C., biphenyl skeleton type epoxy resin having an epoxy equivalent of 188 and a melting point of 106 ° C. (4,4′-bis (2,3-epoxypropoxy) -3,3 ′, 5 , 5′-tetramethylbiphenyl), a phenol novolak resin having a hydroxyl group equivalent of 106 and a softening point of 83 ° C., a phenol aralkyl resin having a hydroxyl group equivalent of 167 and a softening point of 70 ° C. (Mitsui Toatsu; Millex XL-225), triphenylphosphine , Carnauba wax, carbon black, γ-glycidoxypropyltrimethoxysilane as a coupling agent, fused silica, and flame retardant as component (C) of the present invention, which are represented by the following structural formulas 1 to 3

(3 of R _{1 to} R ₆ are hydroxyl groups and the other 3 are hydrogen) are mixed at a weight ratio shown in Table 1 and roll kneaded under conditions of a kneading temperature of 80 to 90 ° C. and a kneading time of 10 minutes. The molding materials of Examples 1 to 6 were produced.

Comparative Examples 1 and 2
Comparative Example 1 with the formulation shown in Table 1 as in Example, except that brominated bisphenol A type epoxy resin and antimony trioxide having an epoxy equivalent of 375, a softening point of 80 ° C. and a bromine content of 48% by weight were used as flame retardants. 2 molding materials were produced.

The properties of the molding materials obtained in Examples and Comparative Examples were evaluated by the following methods.
(1) Hardness when heated Using a mold that molds a disc with a diameter of 100 mm and a thickness of 3 mm, the molding material is molded under conditions of 180 ± 3 ° C, 6.9 ± 0.17 MPa, 90 seconds by transfer press. The hot hardness of the molded product immediately after molding was determined using a Shore hardness meter (D type).
In addition, it is evaluated that the higher the numerical value of the hot hardness, the better.
(2) Water absorption rate A disc having a diameter of 50 mm and a thickness of 3 mm in accordance with JIS-K-6911 was prepared, humidified under conditions of 85 ° C. and 85% RH, and obtained from a change in weight after a predetermined time.
(3) Adhesive The molding material was molded on a 30 μm aluminum foil with a transfer press at 180 ± 3 ° C., 6.9 ± 0.17 MPa for 90 seconds, and then the aluminum foil peeled in the 90 ° direction. The strength was measured.
(4) Flame retardance Using a mold that molds a 1/16 inch thick test piece, the molding material is molded by transfer press under conditions of 180 ± 3 ° C, 6.9 ± 0.17 MPa, 90 seconds. Then, post-curing was performed at 180 ± 5 ° C. for 5 hours. Evaluation followed the UL94-V0 test method.
(5) High temperature storage characteristics Partial silver plating was performed using a test element in which an aluminum wiring with a line / space of 10 μm was formed on a silicon substrate having an outer size of 5 × 9 (mm) and a 5 μm oxide film. A 42 alloy lead frame was connected with silver paste, and a bonding pad and an inner lead of the element were connected with Au wire at 200 ° C. using a thermosonic wire bonder. Thereafter, a 16-pin DIP (Dual Inline Package) was produced by transfer molding, the obtained test IC was stored in a high-temperature bath at 200 ° C., taken out every predetermined time, a continuity test was performed, and the number of defects was examined. .
The evaluation IC package was molded by molding a molding material at 180 ± 3 ° C., 6.9 ± 0.17 MPa, 90 seconds using a transfer press, and then post-cured at 180 ± 5 ° C. for 5 hours. .

The obtained evaluation results are shown in Table 2.

  Examples 1 to 6 of the present invention have markedly improved high-temperature storage characteristics as compared with Comparative Examples 1 and 2 containing a brominated resin and an antimony compound. In particular, since Examples 4 to 6 use a biphenyl skeleton type epoxy resin, the adhesiveness is also good. Although all the examples using the flame retardant of the present invention have good high-temperature storage characteristics and excellent flame retardancy, since Compound 1 does not have a functional group capable of reacting with an epoxy group, this is used as a flame retardant. As shown in Examples 1 and 4, the hot hardness is slightly reduced. Moreover, since all the 6 substituents are hydroxyphenyl groups which can react with an epoxy group in the compound 2, Examples 2 and 5 using this have good curability, but the adhesiveness is slightly lowered. Examples 3 and 6 using Compound 3 in which three of the substituents are hydroxyphenyl groups are particularly excellent in the balance between hot hardness and adhesiveness.

Claims (7)

(A) an epoxy resin having two or more epoxy groups in one molecule;
(B) a compound having two or more phenolic hydroxyl groups in one molecule;
(C) a cyclic phosphazene compound represented by the following formula (I):

(N is an integer of 3 to 5, and R and R ′ represent the same or different alkyl group or aryl group having 1 to 4 carbon atoms.)
(D) inorganic filler,
In which the content of the component (C) is such that the amount of phosphorus atoms is 0.2 to 3.0% by weight with respect to the total amount of the blending components excluding the filler (D). (C) 2 to 4 of n R and n R ′ of component (C) are hydroxyphenyl groups, all others are phenyl groups, (D) component content is molded 70% by weight or more based on the whole material, and (D) the inorganic filler contains one or more selected from aluminum hydroxide, magnesium hydroxide and zinc borate as an inorganic filler having a flame-retardant effect. Epoxy resin molding material for sealing electronic parts. (A) an epoxy resin having two or more epoxy groups in one molecule;
(B) a compound having two or more phenolic hydroxyl groups in one molecule;
(C) a cyclic phosphazene compound represented by the following formula (I):

(N is an integer of 3 to 5, and R and R ′ represent the same or different alkyl group or aryl group having 1 to 4 carbon atoms.)
(D) inorganic filler,
In which the content of the component (C) is such that the amount of phosphorus atoms is 0.2 to 3.0% by weight with respect to the total amount of the blending components excluding the filler (D). an amount, (C) an n-number of R and n number of R 'are all hydroxyphenyl groups of component, (D) in a content of components 70% by weight or more relative to the entire molding material, (D) An epoxy resin molding material for encapsulating electronic parts, comprising at least one selected from aluminum hydroxide, magnesium hydroxide and zinc borate as an inorganic filler having a flame-retardant effect in the inorganic filler. The epoxy resin as component (A) is 4,4′-bis (2,3-epoxypropoxy) -3,3 ′, 5,5′-tetramethylbiphenyl,
Epoxidized phenol and aldehyde novolak resins,
Bisphenol A, bisphenol F, bisphenol S, diglycidyl ether of alkyl-substituted biphenol,
Glycidylamine type epoxy resin,
The epoxy resin molding material for electronic component sealing according to any one of claims 1 to 2, comprising at least one of a linear aliphatic epoxy resin and an alicyclic epoxy resin. (B) resin obtained by condensing or co-condensing phenols or naphthols and aldehydes under an acidic catalyst,
Polyparavinylphenol resin,
The epoxy resin molding material for electronic component sealing according to any one of claims 1 to 3, comprising at least one of a phenol-aralkyl resin having a xylylene group synthesized from phenols and dimethoxyparaxylene. Furthermore, the epoxy resin molding material for electronic component sealing in any one of Claims 1-4 containing a coupling agent. (C) n of a component is 3, The epoxy resin molding material for electronic component sealing in any one of Claims 1-5 . The electronic component obtained by sealing an element with the epoxy resin molding material for electronic component sealing in any one of Claims 1-6 .