JPH10259292A - Epoxy resin molding material for sealing electronic part and electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize dehalogenation and de-antimony reaction and obtain the subject material capable of developing excellent environmental protection property and high-temperature storage characteristics without impairing flame retardance by compounding an epoxy resin with a specific cyclic phosphazene compound as a flame retardance. SOLUTION: This molding material consists essentially of (A) an epoxy resin having >=2 epoxy groups in the molecule [e.g. 4,4'-bis(2,3- epoxypropoxy)-3,3',5,5'-tetramethylbiphenyl], (B) a compound having >=2 phenolic OH groups in the molecule, (C) a compound of the formula [R and R' are each a 1-4C alkyl or an aryl; (n) is 3-5] and (D) an inorganic filler. The content of the component C is 0.2-3.0wt.% in terms of phosphorus amount based on total amount of compounding components excluding the component D and the content of the component D is >=70wt.% based on total amount of molding material.

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 encapsulating semiconductors, particularly a non-halogen epoxy resin molding material for encapsulating electronic parts required from the viewpoint of environmental friendliness. The present invention relates to a molding material suitable for sealing a VLSI requiring strict reliability and an electronic component in which an element is sealed with the molding material.

[0002]

2. Description of the Related Art Conventionally, epoxy resin molding materials have been widely used in the field of sealing elements for electronic parts 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 insert products. Flame retardation of these epoxy resin molding materials is mainly carried out by a combination of a brominated resin such as diglycidyl ether of tetrabromobisphenol A and antimony oxide.

[0003]

In recent years, the problem of dioxin originated from the viewpoint of environmental protection, and there has been a movement to regulate halogenated resins such as decabrom. Similarly, antimony compounds are being regulated from the viewpoint of toxicity, and there is a demand for dehalogenation (debromination) and deantimony of epoxy resin molding materials for encapsulating electronic components. It is also known that bromide ions have an adverse effect on the high-temperature storage characteristics of plastic-sealed ICs. 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 has as its object to provide an epoxy resin material for electronic component sealing having excellent high-temperature storage characteristics.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the inventors have found that the above object can be achieved by blending a specific cyclic phosphazene compound as a flame retardant. They have found and completed the present invention.

That is, the present invention relates to (1) (A) an epoxy resin having two or more epoxy groups in one molecule;
A compound having two or more phenolic hydroxyl groups in one molecule, (C) a compound represented by the following formula (I):

Embedded image (N is an integer of 3 to 5, R and R ′ each represent an alkyl group or an aryl group having 1 to 4 carbon atoms which may be the same or different), and (D) an inorganic filler. A molding material as an essential component, wherein the content of the component (C) is such that the amount of phosphorus atoms is 0.2 to 3.0% by weight based on the total amount of the components except the filler (D). And
(D) The content of the component is 70% by weight based on the whole molding material.
The epoxy resin molding material for electronic component sealing, characterized in that: (2) The epoxy resin molding material for electronic component sealing according to (1), wherein n of the component (C) is 3.
(3) The epoxy resin molding material for encapsulating electronic parts according to the above (1) or (2), wherein n R and n R ′ of the component (C) are all phenyl groups, (4) (C) The epoxy resin for electronic component encapsulation according to the above (1) or (2), wherein 2 to 4 of n R and n R ′ components are hydroxyphenyl groups, and all others are phenyl groups. Molding materials,
(5) The epoxy resin molding material for encapsulating electronic parts according to the above (1) or (2), wherein n R and n R ′ of the component (C) are all hydroxyphenyl groups, (6) (A (1) The electron according to any one of (1) to (5), wherein the component epoxy resin is 4,4′-bis (2,3-epoxypropoxy) -3,3 ′, 5,5′-tetramethylbiphenyl. Epoxy resin molding material for parts encapsulation, (7) above (1) to
(6) An electronic component obtained by sealing the element with the epoxy resin molding material for electronic component sealing according to any one of (6).

[0006]

DETAILED DESCRIPTION OF THE INVENTION (A) used in the present invention
The epoxy resin of the component is not particularly limited as it is generally used in an epoxy resin molding material for sealing electronic components, and examples thereof include phenols such as phenol novolak epoxy resins and orthocresol novolac epoxy resins. Glycidylamine epoxy resin obtained by the reaction of epichlorohydrin with polyamines such as diglycidyl ethers such as bisphenol A, bisphenol F, bisphenol S, and alkyl-substituted biphenols, diaminodiphenylmethane, isocyanuric acid, etc. And linear aliphatic epoxy resins and alicyclic epoxy resins obtained by oxidizing olefin bonds with a peracid such as peracetic acid. Any of these may be used in combination.

Among the epoxy resins shown above, 4,
4'-bis (2,3-epoxypropoxy) -3,
When an alkyl-substituted biphenol type diepoxy resin such as 3 ′, 5,5′-tetramethylbiphenyl is used, the adhesiveness and the hygroscopicity are good, whereby a molding material having excellent reflow crack resistance and moisture resistance is obtained. Can be 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 epoxy resin has low moisture absorption,
The high adhesiveness is not exhibited, and the effect of the present invention on the solder resistance is small. Examples of the epoxy resin include those obtained by epoxidizing 4,4′-bishydroxy 3,3 ′, 5,5′-tetramethylbiphenyl using epichlorohydrin.

[0008] One of the components (B) used in the present invention
Compounds having two or more phenolic hydroxyl groups in the molecule include phenols such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, and naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene and the like. Resin obtained by condensing or co-condensing aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde with an acidic catalyst, polyparavinylphenol resin, xylylene group synthesized from phenols and dimethoxyparaxylene And a phenol-aralkyl resin having the following formula. These may be used alone or in combination of two or more.

The equivalent ratio of the epoxy resin (A) to the phenol compound (B) (the number of hydroxyl groups in (B) / (A))
Is not particularly limited, but is preferably set in the range of 0.7 to 1.3 in order to reduce the amount of each unreacted component.

[0010] A curing accelerator for accelerating the curing reaction between the epoxy resin and the phenol resin can be used as required. As this curing accelerator, for example, 1,8
-Diazabicycloalkenes and derivatives thereof such as diazabicyclo (5,4,0) undecene-7 and tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol and tris (dimethylaminomethyl) phenol Imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole and 2-heptadecylimidazole; organic phosphines such as tributylphosphine, methyldiphenylphosphine and triphenylphosphine; and tetraphenylphosphonium. Tetra-substituted phosphonium / tetra-substituted borate such as tetraphenyl borate, 2-ethyl-4-methylimidazole / tetraphenyl borate, N-methylmorpholine / tetraf And the like tetraphenyl boron salts such as Niruboreto.

The cyclic phosphazene compound (C) used as a flame retardant in the present invention is represented by the following formula (I):

Embedded image (N is an integer of 3 to 5, and R and R ′ each represent an alkyl group or an aryl group having 1 to 4 carbon atoms which may be the same or different), a 6-membered trimer ring, A tetramer 8-membered ring and a pentamer 10-membered ring can be used alone or as a mixture. It is preferable to use a trimer as a main component from the fluidity of the epoxy resin molding material.

In the above formula (I), n R's and R ''s may be the same or different and are an alkyl group or an aryl group having 1 to 4 carbon atoms. In such a case, R and R 'are 6 substituents, which may be the same or different. An aryl group is preferable from the viewpoint of heat resistance and moisture resistance of the epoxy resin molding material. Particularly, it is preferably a phenyl group, and more preferably a hydroxyphenyl group. When a hydroxyphenyl group is introduced, n R and n R ′ may all be hydroxyphenyl groups, but preferably 2 to 4 introductions. When the number of hydroxyphenyl groups is 5 or more, the epoxy resin cured product is apt to become brittle, and when the number is less than 2, components that are not taken into the crosslinked structure of the epoxy resin appear, so that the heat resistance tends to decrease.

Preferred structures of the cyclic phosphazene compound (C) used in the present invention include, for example, the following formulas (II) to (IV)

Embedded image

Embedded image

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

The amount of the cyclic phosphazene compound to be added is 0.2 to 0.2% based on all the other components except the filler.
It must be within the range of 3.0% by weight. 0.2
If the amount is less than 3.0% by weight, the flame retardant effect is not exhibited, and
If the content is more than 10% by weight, the moisture resistance is reduced.

According to the present invention, there is provided a non-halogen, non-antimony non-flammable epoxy resin molding material for sealing electronic parts having excellent reliability and moldability by using a specific cyclic phosphazene compound as the component (C). Things. It is generally known that the combined use of a phosphorus compound and a nitrogen compound is good for flame retardancy. However, the present invention uses phosphorus atom as a flame retardant component of an epoxy resin molding material for semiconductor encapsulation capable of exhibiting excellent reliability. And a nitrogen atom in the structure.

Further, it is necessary to use an inorganic filler as the filler from the viewpoint of reducing the hygroscopicity and improving the strength.
As the inorganic filler of the component (D) in the present invention, powders of fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, boron nitride, beryllia, zirconia, and the like, or spherical powders thereof One or more kinds of beads, single crystal fibers such as potassium titanate, silicon carbide, silicon nitride, and alumina, and glass fibers can be used. Further, 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 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-mentioned inorganic fillers, fused silica is preferred from the viewpoint of reducing the coefficient of linear expansion, and alumina is preferred from the viewpoint of high thermal conductivity, and the filler shape is spherical from the viewpoint of fluidity during molding and mold abrasion. Is preferred.

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

The molding material in the present invention can be prepared by any method as long as the various raw materials can be uniformly dispersed and mixed. As a general method, the raw materials having a predetermined blending amount are sufficiently mixed by a mixer or the like. After mixing, melt-kneading with a mixing roll, extruder, etc., cooling,
A pulverizing method can be used.

On a supporting member such as a lead frame, a wired tape carrier, a wiring board, glass, or a silicon wafer, active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils are provided. An electronic component can be manufactured by mounting the element and sealing a necessary portion with the molding material for sealing of the present invention. An example of such an electronic component is 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. Also, active elements such as semiconductor chips, transistors, diodes, thyristors, and / or passive elements such as capacitors, resistors, and coils are connected to wiring formed on a wiring board or glass by wire bonding, flip chip bonding, soldering, or the like. , A COB module, a hybrid IC, a multi-chip module, and the like, which are sealed with the molding material of the present invention. As a method of sealing the electronic component, a low-pressure transfer molding method is the most common, but an injection molding method, a compression molding method, or the like may be used.

[0020]

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

Examples 1 to 6 Cresol novolak type epoxy resin having an epoxy equivalent of 200 and a softening point of 67 ° C., an epoxy equivalent of 188 and a melting point of 106
C. biphenyl skeleton type epoxy resin (4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'
Phenol novolak resin having a hydroxyl equivalent of 106 and a softening point of 83 ° C., a hydroxyl equivalent of 16
7, a phenol-aralkyl resin having 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 as a flame retardant, compound 1 to compound 3 which are component (C) of the present invention and are represented by the following structural formula:

Embedded image

Embedded image

Embedded image (Three of R _{1 to} R ₆ represent hydroxyl groups and the other three represent hydrogen) at a weight ratio shown in Table 1 and a kneading temperature of 80 to 9
Roll kneading was performed under the conditions of 0 ° C. and a kneading time of 10 minutes to produce molding materials of Examples 1 to 6.

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

[0023]

[Table 1]

The properties of the molding materials obtained in Examples and Comparative Examples were evaluated by the following methods. (1) Hot hardness Using a mold for forming a disk having a diameter of 100 mm and a thickness of 3 mm, using a transfer press at 180 ± 3 ° C and 6.9 ±.
A molding material is molded under the conditions of 0.17 MPa and 90 seconds, and the hardness of the molded product immediately after molding is measured by a Shore hardness tester (D type).
Determined by In addition, it is evaluated that the higher the value of the hardness at the time of heating, the better. (2) Water absorption 50 mm in diameter and 3 in thickness according to JIS-K-6911
A disk having a thickness of mm was prepared, humidified under the conditions of 85 ° C. and 85% RH, and determined from a change in weight after a predetermined time. (3) Adhesiveness A molding material is formed on a 30 μm aluminum foil by a transfer press under the conditions of 180 ± 3 ° C., 6.9 ± 0.17 MPa, 90 seconds, and then the aluminum foil is peeled in a 90 ° direction. The strength was measured. (4) Flame retardancy Using a mold for molding a test piece 1/16 inch thick,
180 ± 3 ° C, 6.9 ± 0.1 with transfer press
The molding material is molded under the conditions of 7 MPa and 90 seconds.
Post-curing was performed at 80 ± 5 ° C. for 5 hours. Evaluation is UL94-
The V0 test method was followed. (5) High temperature storage characteristics Line / space is 10 μm on a silicon substrate having an outer size of 5 × 9 (mm) and a 5 μm oxide film.
Using a test element having aluminum wiring formed thereon, it was connected to a 42-alloy lead frame partially silver-plated with silver paste, and a thermosonic wire bonder was used to connect the alloy to the lead frame.
At 0 ° C, the bonding pads and inner leads of the device are Au
Connected by wire. After that, transfer molding
Pin type DIP (Dual Inline Package)
e) was prepared, and the obtained test IC was stored in a high-temperature bath at 200 ° C., taken out every predetermined time and subjected to a continuity test, and the number of defects was examined. The IC package for evaluation was molded by a transfer press at 180 ± 3 ° C. and 6.9 ± 0.17.
The molding material was molded under the conditions of 90 MPa for 90 seconds.
After 5 hours at 0 ± 5 ° C., curing was performed.

Table 2 shows the obtained evaluation results.

[Table 2]

In Examples 1 to 6 of the present invention, the high-temperature storage characteristics are remarkably improved as compared with Comparative Examples 1 and 2 containing a brominated resin and an antimony compound. Particularly, in Examples 4 to 6, the biphenyl skeleton type epoxy resin is used, so that the adhesiveness is also good. All of the examples using the flame retardant of the present invention have good high-temperature storage characteristics and excellent flame retardancy, but since Compound 1 does not have a functional group capable of reacting with an epoxy group,
When this is used as a flame retardant, the hardness when heated is slightly reduced as shown in Examples 1 and 4. In addition, since all of the six substituents of the compound 2 are hydroxyphenyl groups capable of reacting with an epoxy group, Examples 2 and 5 using the compound have good curability, but have a slight decrease in adhesiveness. Examples 3 and 6 using compound 3 in which three of the substituents are hydroxyphenyl groups are particularly excellent in the balance between the hardness when heated and the adhesiveness.

[0027]

The epoxy resin molding material for encapsulating electronic parts obtained by the present invention can achieve flame retardancy with non-halogen and non-antimony as shown in the examples, and is used for electronic parts such as ICs and LSIs. Is sealed, the product is excellent in moldability, and a product having excellent reliability such as moisture resistance and high-temperature storage characteristics can be obtained, and its industrial value is great.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 23/31

Claims (7)

[Claims] (1) 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 compound having the following formula (I): Formula 1 (N is an integer of 3 to 5, R and R 'each represent an alkyl group or an aryl group having 1 to 4 carbon atoms which may be the same or different), (D) an inorganic filler, Wherein the content of the component (C) is 0.2 to 3.0% by weight based on the total amount of the components except the filler (D). An epoxy resin molding material for encapsulating electronic components, wherein the content of the component (D) is 70% by weight or more based on the whole molding material. 2. The epoxy resin molding material according to claim 1, wherein n of component (C) is 3. 3. The epoxy resin molding material for sealing electronic parts according to claim 1, wherein n R and n R ′ of the component (C) are all phenyl groups. 4. The method according to claim 1, wherein 2 to 4 of n R and n R ′ of the component (C) are hydroxyphenyl groups, and all others are phenyl groups. Epoxy resin molding material for sealing electronic components. 5. The method according to claim 1, wherein n R and n R ′ of the component (C) are all hydroxyphenyl groups.
The epoxy resin molding material for sealing electronic parts according to the above. 6. The epoxy resin as component (A) is 4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5.
The epoxy resin molding material for sealing electronic parts according to any one of claims 1 to 5, which is 5'-tetramethylbiphenyl. 7. An electronic component obtained by sealing an element with the epoxy resin molding material for electronic component sealing according to any one of claims 1 to 6.