JPH09129787A - Resin-sealed semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize solder crack resistance and heat cycle crack resistance by making a lead frame of a copper-based metal, and using, as essential element of a sealing material, polyglycidyl ether of polyphenols bonded with phenols with an alicyclic hydrocarbon group as a coupling group, a hardening agent and an inorganic filler. SOLUTION: An electrode portion within a semiconductor element and a lead frame made of a copper-based metal are joined with each other and sealed by a sealing material in such a manner as to fix to semiconductor element and the lead frame. This sealing material contains, as essential elements, polyglycidyl ether of polyphenols having structure bonded with phenols with an alicyclic hydrocarbon group as a coupling group, a hardening agent and an inorganic filler. Thus, excellent solder crack resistance and heat cycle crack resistance, and significantly high heat dissipation property may be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new resin-encapsulated semiconductor which is particularly excellent in heat dissipation and solder crack resistance during surface mounting.

[0002]

2. Description of the Related Art In recent years, measures against heat generation due to an increase in power consumption accompanying the increase in speed and density of semiconductor elements have begun to become a subject, and in the field of plastic packages, there is an urgent need to cope with the problem. In addition, the lead frame is one of the important parts that have a heat dissipation effect in the semiconductor device, but conventionally, a copper-containing alloy is widely used for discrete (individual semiconductor) because of its high thermal conductivity and excellent heat dissipation. In addition, copper-containing alloys having excellent heat dissipation properties have been reviewed in MOS type semiconductors (DRAM and the like) used in personal computer mounted memories.

[0003]

However, since the copper-containing alloy lead frame has a remarkably high linear expansion coefficient, the filling rate of the inorganic filler is 85 to 90 for the purpose of improving solder crack resistance during surface mounting. Since the difference between the linear expansion coefficient and the encapsulating material that has been increased to 10% by weight is very large, the filling rate cannot be sufficiently increased, and problems such as cracks and peeling are likely to occur during the heat cycle. Had. That is, the means for improving the solder crack resistance by increasing the filling rate of the inorganic filler has been extremely difficult to implement in a semiconductor device combined with a copper-containing alloy lead frame.

The problem to be solved by the present invention is that when a copper-based metal typified by a copper-containing alloy is used in a lead frame, solder crack resistance and heat cycle crack resistance are remarkably excellent, and heat resistance It is intended to provide a resin-encapsulated semiconductor which is also excellent in radiation efficiency.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have a semiconductor element and a lead frame joined to an electrode portion in the element, and fix the semiconductor element and the lead frame. In a semiconductor device sealed with a sealing material, a polyphenol having a structure in which a copper-based metal is used as a lead frame, and the sealing material has a structure in which an alicyclic hydrocarbon group is bonded to a phenol as a bonding group. It was found that the above-mentioned problems can be solved by using a polyglycidyl ether containing the above-mentioned polyglycidyl ether, a curing agent thereof, and an inorganic filler, and the present invention has been completed.

That is, the present invention has a semiconductor element and a lead frame joined to an electrode portion in the element, and a semiconductor device sealed with a sealing material so as to fix the semiconductor element and the lead frame. In which the lead frame is made of a copper-based metal, and the sealing material has a structure in which an alicyclic hydrocarbon group is bonded to a phenol as a binding group (polyglycidyl ether (A))
And a hardening agent (B) and an inorganic filler (C) as essential components.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The lead frame used in the present invention is composed of a copper-based metal, and examples thereof include copper and a copper-containing alloy. The latter is preferable from the viewpoint of strength. -Tin alloy, copper-iron alloy, copper-zirconium alloy, copper-silver alloy, copper-chromium-zirconia alloy, copper-
Chromium-tin alloy, copper-iron-magnesium alloy, copper-tin-
Examples thereof include silicon alloys, copper-nickel-tin alloys, oxygen-free copper, and alloys obtained by adding phosphorus or magnesium to them. However, it is not limited to these specific examples.

Further, in the polyglycidyl ether (A) used in the present invention, the lead frame is made of a copper-based metal, and the sealing material is bonded to phenols using an alicyclic hydrocarbon group as a binding group. It is a polyglycidyl ether of polyphenols having the above structure and is usually used as a mixture of various structures and molecular weights.

Examples of the phenols include phenol and substituted phenols having an alkyl group, an alkenyl group, an allyl group, an aryl group, an aralkyl group or a halogen group bonded thereto. Specific examples include cresol, xylenol, ethylphenol, isopropylphenol, butylphenol, octylphenol, nonylphenol, vinylphenol, isopropenylphenol, allylphenol, phenylphenol, benzylphenol, chlorophenol, and bromophenol (o, m, p, respectively). -Isomer), bisphenol A, naphthol, dihydroxynaphthalene, and the like, but are not limited thereto. Moreover, these may be mixed. Among these, phenol and cresol are particularly preferred from the viewpoint of excellent fluidity and curability.

On the other hand, the alicyclic hydrocarbon group serves as a bonding group of the phenol skeleton portion, and its structure is not particularly limited, but among them, a cyclohexane ring or a cyclohexene ring is contained in the skeleton. It is preferable that the cured product has low water absorption and excellent water resistance. Among them, specifically, dicyclopentadiene, limonene, 3a, 4,7,7a-tetrahydroindene, norbornene, vinylhexene, in terms of coefficient of linear expansion with copper-based metal, water resistance and heat resistance. , A divalent hydrocarbon group based on an unsaturated bond in the molecular skeleton of α-terpinene and β-terpinene is preferable. These compounds may be used alone or in combination of two or more. Further, among these, a divalent hydrocarbon group based on an unsaturated bond in the molecular skeleton of dicyclopentadiene is preferable because the heat resistance and moisture resistance of the cured product can be further improved.

As such polyglycidyl ether (A), more specifically, for example, those represented by the following general formula are preferred.

[0012]

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(In the formula, R is independently an alkyl group or a hydrogen atom, m is an integer of 1 to 4 representing the number of substituents R, X is an aliphatic hydrocarbon group, and m is 1 to n is an integer of 0 to 10 indicating a repeating unit.)

Such polyglycidyl ether (A)
As mentioned above, is a mixture of compounds having various structures and has a molecular weight distribution, but the content of the compound having two glycidyl ether groups per molecule, that is, the binuclear compound, is 40 to It is preferable that it is in the range of 80% by weight from the viewpoint that the fluidity of the sealing material is improved and the moldability is improved, and further, the melt viscosity at 150 ° C. is 7.0 poise or less and the epoxy equivalent is 220 to 300 g. Epoxy resin in the range of / eq makes it possible to further increase the filling of the inorganic filler, and also makes the cured product remarkably good in water resistance, so that it is more resistant to solder cracking and heat cycle cracking. It will be excellent.

Further, the polyglycidyl ether (A) is
Its melt viscosity at 150 ° C. is 7.0 poise or less,
Further, the content of the binuclear component is in the range of 40 to 80% by weight, and the epoxy equivalent thereof is 220 to 300 g /
The range of eq is preferable because it further improves the solder crack resistance and the heat cycle crack resistance.

The content of this binuclear body is a value represented by a weight ratio analyzed by gel permeation chromatography (GPC).

The polyglycidyl ether (A) having such a molecular structure and satisfying the above conditions has a linear expansion between the lead frame and the semiconductor encapsulating material even if the inorganic filler (C) is highly filled. The solder crack resistance is remarkably good without causing a difference in the coefficient, and furthermore, the polyglycidyl ether (A) itself has a low water absorption rate and good adhesion to the copper-based alloy lead frame. Inorganic filler (C)
Even if it is not highly filled, it becomes a cured product of a package having a low water absorption rate and also has good solder crack resistance and heat cycle crack resistance.

On the other hand, the above polyglycidyl ether (A)
Other epoxy resins, such as ortho-cresol novolac type epoxy resin and biphenyl type epoxy resin,
Due to its high water absorption rate, if the inorganic filler is increased to 85% by weight or more for the purpose of improving the solder crack resistance, the linear expansion coefficient (8 to 10 ppm) of the cured product of the package is copper alloy lead frame. Since the coefficient of linear expansion is much lower than (17 ppm), thermal stress is generated at the interface, and defects such as cracks and peeling are likely to occur during the heat cycle.

The method for producing the polyglycidyl ether (A) detailed above is not particularly limited, but, for example, after the polyaddition reaction between the above-mentioned phenols and the unsaturated alicyclic compound is carried out, , And a method of reacting epihalohydrin.

The unsaturated alicyclic compound used here is a raw material component for forming an alicyclic hydrocarbon group, and is an aliphatic cyclic hydrocarbon compound having two or more unsaturated double bonds in one molecule. If it is, it is not particularly limited, but if it is exemplified, dicyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, 5-vinylnorborna-2-ene,
Examples include α-terpinene, β-terpinene and limonene. Among these, dicyclopentadiene is preferred from the viewpoint of the property balance, particularly the heat resistance and the hygroscopicity. Further, since dicyclopentadiene is contained in the petroleum fraction, industrial dicyclopentadiene may contain other aliphatic or aromatic dienes as impurities,
Considering heat resistance, curability, moldability, etc., it is desirable to use a product having a purity of 90% by weight or more of dicyclopentadiene.

Polyphenols obtained by polyaddition reaction of phenols and unsaturated alicyclic compounds (hereinafter,
The abbreviated as "intermediate") is not particularly limited in its production conditions, but the melt viscosity of polyglycidyl ether (A) at 150 ° C. is 7.0 poise or less, and 2
In order to set the content of the core component in the range of 40 to 80% by weight, it is preferable to adjust the molar ratio of the phenols and the unsaturated alicyclic compound during the reaction. It is preferable to use 4 mol or more of phenols per mol. Among them, when synthesized within the range of phenols / unsaturated alicyclic compound = 2.5 / 1 to 15/1 (molar ratio), a preferable intermediate can be obtained for obtaining the above polyglycidyl ether (A).

More specifically, the method for producing the above-mentioned intermediate will be described in detail. A polyaddition catalyst is added to a molten or solution phenol, and an unsaturated alicyclic compound is appropriately added thereto, followed by heating with stirring. Then, the polyaddition reaction is allowed to proceed, and then excess phenols are distilled and recovered to obtain a polyaddition reaction product. Examples of the polyaddition catalyst include inorganic acids such as hydrochloric acid and sulfuric acid, organic acids such as paratoluenesulfonic acid, and Lewis acids such as AlCl3 and BF3.

Then, the desired polyglycidyl ether (A) can be obtained by reacting the intermediate thus obtained with epihalohydrin. This reaction may be carried out by a known method, for example, The reaction of is mentioned.

First, the hydroxyl group in the intermediate is 2 to 15
From the viewpoint of being excellent in the effect of reducing the melt viscosity among them, preferably 3 to 10 equivalents of epihalohydrin are added and dissolved, and then 0.8 to 1.2 relative to the hydroxyl group in the intermediate.
An equivalent amount of 10 to 50% NaOH aqueous solution is applied at a temperature of 50 to 80 ° C. for 3 to 5 hours. After being properly adjusted to 0.
Continue stirring for about 5 to 2 hours, and after standing, discard the lower layer saline. Next, the excess epihalohydrin is recovered by distillation to obtain a crude resin. To this, an organic solvent such as toluene or MIBK is added, and the desired resin can be obtained through a water washing-dehydration-filtration-desolvation step. In addition, a solvent such as dioxane or DMSO may be used in the reaction for the purpose of reducing the amount of impurity chlorine.

The epihalohydrin used here is
Epichlorohydrin is the most common, but epiiodohydrin, epibromohydrin, β-methylepichlorohydrin and the like can also be used.

As the curing agent (B) used in the present invention, all compounds which are commonly used as curing agents for epoxy resins can be used and are not particularly limited. For example, phenol novolac is used. Resin, orthocresol novolac resin, bisphenol A novolac resin, bisphenol F novolac resin, phenols-dicyclopentadiene polyaddition type resin, dihydroxynaphthalene novolac resin, polyhydric phenols having a xylidene group as a bonding group, phenol-aralkyl resin , Naphthol resins Diaminetriamine, triethylenetetramine and other aliphatic amines, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone and other aromatic amines, polyamide resins and modified products thereof Maleic anhydride, phthalic anhydride,
Acid anhydride curing agents such as hexahydrophthalic anhydride, pyromellitic anhydride, dicyandiamide, imidazole,
Latent curing agents such as BF3 -amine complexes and guanidine derivatives. Above all, for semiconductor encapsulants, aromatic hydrocarbon-formaldehyde resins such as the above-mentioned phenol novolak resins have excellent curability, moldability and heat resistance, and phenol-aralkyl resins have curability, moldability and low water absorption. It is preferable because it is excellent. The amount of these curing agents used may be any amount as long as it cures the epoxy resin, and is not particularly limited, but preferably the number of epoxy groups contained in one molecule of the epoxy resin used and the activity in the curing agent. This is the amount at which the number of hydrogen is close to the equivalent.

When each of the above compounds is used as a curing agent, a curing accelerator can be appropriately used. As the curing accelerator, any known and commonly used curing accelerators can be used, and examples thereof include phosphorus compounds, tertiary amines, imidazoles, organic acid metal salts, Lewis acids, amine complex salts, and the like. In addition, two or more kinds can be used in combination.

The inorganic filler (C) used in the present invention is essential not only for enhancing the mechanical strength and hardness of the cured product, but also for achieving low water absorption and low linear expansion coefficient and enhancing solder crack resistance. It is an ingredient. The blending amount thereof is not particularly limited, but when used in a range of 75 to 95% by weight in the composition, those characteristics become particularly remarkable,
In particular, it is preferable in the application of semiconductor encapsulant because the solder crack resistance is very excellent.

Examples of such an inorganic filler (C) include, but are not limited to, fused silica, crystalline silica, alumina, talc, clay and glass fiber. Among these, fused silica, especially in semiconductor encapsulating material applications,
Crystalline silica is generally used, and fused silica is particularly preferable because it has excellent fluidity. Further, spherical silica, crushed silica and the like can be used.

In the present invention, in addition to the above-mentioned polyglycidyl ether (A) which is an essential component, other epoxy resin (D) may be used in combination. As the epoxy resin (D) used at this time, any known and commonly used epoxy resin can be used. For example, bisphenol A diglycidyl ether type epoxy resin, phenol novolak type epoxy resin, orthocresol novolak type epoxy resin, bisphenol A novolak type Examples include, but are not limited to, epoxy resins, bisphenol F novolak type epoxy resins, brominated phenol novolak type epoxy resins, naphthol novolak type epoxy resins, and biphenyl type bifunctional epoxy resins. Of these, orthocresol novolak epoxy resin is particularly preferable from the viewpoint of excellent heat resistance, and biphenyl type bifunctional epoxy resin is preferable from the viewpoint of excellent fluidity.

If necessary, various known and commonly used additive components such as a coloring agent, a flame retardant, a release agent, and a coupling agent can be appropriately blended. Further, in order to prepare a molding material from the epoxy resin composition of the present invention, the epoxy resin, the curing agent, the curing accelerator, and other additives are sufficiently and uniformly mixed with a mixer or the like, and then further heated roll or kneader. It can be obtained by melt-kneading with, for example, pulverizing after injection or cooling.

In the semiconductor encapsulating material of the present invention, in addition to the above-mentioned components of the epoxy resin composition, tetrabromobisphenol A type epoxy resin, brominated epoxy resin such as brominated phenol novolac type epoxy resin, antimony trioxide, etc. , Flame retardants such as hexabromobenzene, colorants such as carbon black and red iron oxide, release agents such as natural wax and synthetic wax, and low-stress additives such as silicone oil, synthetic rubber and silicone rubber. You may mix | blend an agent suitably.

In order to prepare a molding material using the semiconductor encapsulating material of the present invention, the above components are sufficiently uniformly mixed by a mixer or the like, and then further melt-kneaded by a hot roll or a kneader, and then injection or It can be obtained by crushing after cooling and tableting.

[0034]

EXAMPLES Next, the present invention will be specifically described with reference to production examples, examples and comparative examples of the epoxy resin. In the examples, all parts are by weight unless otherwise specified.

The melt viscosity is R at 50 Hz.
eseach equipment LTD. "ICI"
CONE & PLATE VISCOMETER ". The content of the binuclear component is determined by a gel permeation chromatography (GP) manufactured by Tosoh Corporation.
C) "(measurement conditions: flow rate = 1.0 ml / min, pressure = 92)
Kg / cm2, column = G4,3,2,2HXL, detector = RI 32 × 10 −6 RIUFS). The softening point is "Softening Point Measuring Instrument" manufactured by Meifou Seisakusho Co., Ltd. (Heating device:
HU-MK, detector ASP-M2) measured.

Production Example 1 (Polyglycidyl ether (A)
Production example) Stirrer, thermometer, four-necked flask with 940 g of phenol
(10 mol) was added with 21 g of BF3 / phenol complex and mixed thoroughly. Then dicyclopentadiene 204g
(1.5 mol) was added over 2 hours while keeping the system temperature at 90 to 95 ° C. After that, the temperature in the system was kept at 95 ° C., and the mixture was heated and stirred for 2 hours, and the resulting reaction product solution had a magnesium compound “KW-1000” (trade name; Kyowa Chemical Industry Co., Ltd.
43 g (manufactured by Co., Ltd.) was added, the mixture was stirred for 30 minutes to deactivate the catalyst, and then the reaction solution was filtered. Excess phenol was distilled and recovered from the obtained transparent solution to obtain a brown solid resin 40.
3 g were obtained. This resin had a softening point of 95 ° C. and a hydroxyl equivalent of 171 g / eq.

Epichlorohydrin 9 was added to 342 g of this resin.
Add 25 g (10 mol) and dissolve. 2 at 80 ℃
440 g (2.2 mol) of 0% NaOH was added dropwise with stirring over 3 hours, the stirring was continued for another 30 minutes, and then the mixture was allowed to stand. After discarding the saline solution in the lower layer and distilling and collecting epichlorohydrin at 150 ° C, MIBK600 was added to the crude resin.
g, and then 250 g of water was added and the mixture was washed with water at 80 ° C. After discarding the lower layer washing water, MIBK was desolvated at 150 ° C. through dehydration and filtration to obtain 409 g of the target epoxy resin (I). This resin was a brown solid and had a softening point of 61 ° C., a melt viscosity at 150 ° C. of 0.6 poise, a binuclear component content of 55% by weight, and an epoxy equivalent of 260 g / eq.

Production Example 2 (Polyglycidyl ether (A))
Production Example of Example 1) Example 1 was repeated except that the intermediate obtained in Production Example 1 was used and epichlorohydrin was changed to 1110 g (12 mol).
In the same manner as in (4), 418 g of epoxy resin (II) was obtained. This resin was a brown solid and had a melt viscosity of 58 poise at a softening point of 58 ° C. and 150 ° C., a binuclear component content of 58% by weight, and an epoxy equivalent of 242 g / eq.

Production Example 3 (Polyglycidyl ether (A))
Production Example of) 272 g of dicyclopentadiene used in producing the intermediate
389 g of an epoxy resin (III) was obtained in the same manner as in Production Example 1 except that the amount was changed to (2 mol). This resin is a brown solid and has a melting point of 84 ° C., a melt viscosity of 4.5 poise at 150 ° C., a dinuclear component content of 44% by weight, and an epoxy equivalent of 28.
It was 3 g / eq.

Examples 1 to 3 and Comparative Examples 1 to 3 Mixtures prepared according to the formulations shown in Table 1 were mixed at room temperature with a mixer and 70 to 100 with a biaxial hot roll.
The mixture was kneaded at ℃, cooled and pulverized to obtain a molding material. The molding material obtained by crushing was made into a tablet, which was then 175 ° C., 70 kg / cm ² , 12 using a low-pressure transfer molding machine.
A 6 mm × 6 mm silicon chip was sealed with a 52-pin copper-containing alloy lead frame for various tests under the condition of 0 seconds, and then cured at 180 ° C. for 5 hours.

Various test methods are as follows. Water absorption rate: The sealed semiconductor was treated under an environment of 85 ° C. and 85% 168 hours for 168 hours, and then the weight increase rate was measured to obtain the water absorption rate.・ Solder crack resistance: sealed semiconductor is 85 ℃ ・ 85
The sample was treated in an environment of% RH for 168 hours and then immersed in a solder bath at 260 ° C. for 10 seconds, and then external cracks were observed with a microscope to measure the crack generation rate.・ Heat cycle crack resistance: -1 for sealed semiconductor
The heat cycle of 96 ° C. × 1 minute to 260 ° C. × 30 seconds was repeated, and after 20 cycles, external cracks were observed with a microscope to measure the crack generation rate.

The following epoxy resins were used for comparative evaluation.・ Orthocresol novolac type epoxy resin (EC
N) (trade name: EPI, manufactured by Dainippon Ink and Chemicals, Inc.)
CLON N-665, softening point 68 ° C, epoxy equivalent 2
08g / eq) ・ Biphenyl type epoxy resin (Okaka Shell Epoxy Resin Co., Ltd. trade name: Epicoat YX-4000H, melting point 1
05 ℃, Epoxy equivalent 195g / eq) In addition, as a flame retardant epoxy resin, EPICLON 1
53 (Tetrabromobisphenol A type epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc., bromine content 48% by weight, softening point 70 ° C., epoxy equivalent 401 g / eq), Phenolite TD-2131 (phenol A novolak resin (manufactured by Dainippon Ink and Chemicals, Inc., softening point 80 ° C., hydroxyl equivalent 104 g / eq) was used.

[0043]

[Table 1]

[0044]

The problem to be solved by the present invention is that when a copper-based metal typified by a copper-containing alloy is used for a lead frame, solder crack resistance and heat cycle crack resistance are remarkably excellent. Another object of the present invention is to provide a resin-encapsulated semiconductor excellent in heat dissipation.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C08L 63/00 NKX H01L 23/48 V H01L 23/48

Claims (7)

[Claims] 1. A semiconductor device comprising a semiconductor element and a lead frame joined to an electrode portion in the element, and a semiconductor device sealed with a sealing material so that the semiconductor element and the lead frame are fixed to each other. A polyglycidyl ether (A) of a polyphenol having a structure in which the frame is composed of a copper-based metal, and the sealing material has a structure in which an alicyclic hydrocarbon group is bonded to a phenol as a binding group, and a curing agent A resin-sealed semiconductor device comprising (B) and an inorganic filler (C) as essential components. 2. The resin-encapsulated semiconductor device according to claim 1, wherein the content of the inorganic filler (C) in the encapsulating material is 75 to 95% by weight. 3. A polyglycidyl ether (A) is a compound having two glycidyl ether groups per molecule (hereinafter, abbreviated as “dinuclear compound”) in the component (A) 4
The resin-encapsulated semiconductor device according to claim 1, wherein the resin-encapsulated semiconductor device is contained in a proportion of 0 to 80% by weight. 4. The polyglycidyl ether (A) is 15
The resin-encapsulated semiconductor device according to claim 1, 2 or 3, which has a melt viscosity at 0 ° C of 7.0 poise or less. 5. The resin-encapsulated semiconductor device according to claim 1, wherein the polyglycidyl ether (A) has an epoxy equivalent of 220 to 300 g / eq. 6. The resin encapsulation according to claim 1, 2, 3, 4, or 5, wherein the polyglycidyl ether (A) is an epoxy resin obtained by reacting a polyaddition reaction product of dicyclopentadiene and phenol with epihalohydrin. Static semiconductor device. 7. The polyglycidyl ether (A) is an epoxy resin obtained by reacting a polyaddition reaction product of dicyclopentadiene and phenol with epihalohydrin,
And the content of the binuclear body is 45 to 65% by weight, and 1
The resin-encapsulated semiconductor device according to claim 1, wherein the melt viscosity at 50 ° C. is 2.0 poise or less, and the epoxy equivalent is 235 to 280 g / eq.