JP3267144B2 - Epoxy resin composition for sealing material and semiconductor device using the same - 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 composition for a sealing material used for sealing a semiconductor or the like, and a semiconductor device using the same.

[0002]

2. Description of the Related Art As a method for sealing electronic components such as semiconductor devices, a method using ceramic or thermosetting resin has been conventionally used. Among them, sealing with an epoxy resin composition is more preferable than the balance between economy and performance,
Widely used. A semiconductor device sealed with the epoxy resin composition for a sealing material (hereinafter referred to as a sealing resin) has, for example, a semiconductor element mounted on a metal for a lead frame, and the semiconductor element and the lead frame are bonded with a bonding wire or the like. They are electrically connected to each other, and are formed by sealing the entire semiconductor element and a part of the lead frame with a sealing resin.

As the above-mentioned lead frame, a lead frame made of a copper alloy from the viewpoint of electric conductivity and a lead frame made of a 42 alloy alloy from the viewpoint of the coefficient of thermal expansion are generally used. Since these lead frames have low adhesion to bonding wires such as gold wires, the parts to be connected to the bonding wires of the lead frame are plated in advance with silver or gold, then connected to the bonding wires, and the connection is made. Methods to improve reliability are being considered.

Further, when a cured product of a sealing resin (hereinafter referred to as a cured resin) absorbs moisture, the moisture absorbed by the soldering at the time of mounting the electronic component on the mother board expands rapidly, and the moisture is expanded. There was a case where cracks were generated inside the cured product and the reliability was reduced. Therefore, as an improvement in the moisture absorption solder heat resistance, by filling the sealing resin with an inorganic filler to reduce the proportion of the epoxy resin, which is a component that is easily absorbed by the sealing resin, to reduce the amount of moisture absorption of the cured resin, A method using an epoxy resin or the like having a low moisture absorption rate, a method using a material obtained by treating the surface of an inorganic filler with a silane coupling agent or the like have been studied.

As a method using an epoxy resin having a low moisture absorption, a method using a dicyclopentadiene type epoxy resin is being studied.

However, when an inorganic filler is contained at a high ratio in the sealing resin and a dicyclopentadiene type epoxy resin is contained at a high ratio in all the epoxy resins to improve the heat resistance to moisture absorption, the moldability is increased. Is reduced and air bubbles remain inside the cured resin, or due to the temperature cycle exposed when actually using the semiconductor device, the joint between the silver plated part of the lead frame etc. and the cured resin It is presumed that the adhesion was low, but cracks sometimes occurred. Therefore, even if a high ratio of inorganic filler is contained in the sealing resin, and a high ratio of dicyclopentadiene-type epoxy resin is contained in all epoxy resins, the moldability is excellent and the lead frame and the resin are cured. There is a demand for a sealing resin capable of sealing with high adhesiveness to an object.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and contains an inorganic filler in a high ratio in a sealing resin and a dicyclopentadiene type epoxy resin. Is a sealing resin in which is contained in a high ratio in all epoxy resins, and an object thereof is to provide a sealing resin excellent in both adhesiveness between a lead frame and a cured resin and moldability. It is another object of the present invention to provide a semiconductor device which is excellent in both adhesiveness and moldability between a lead frame and a cured resin using the sealing resin.

[0008]

The sealing resin (epoxy resin composition for sealing material) according to claim 1 of the present invention comprises an epoxy resin, a curing agent, an inorganic filler and a silane coupling agent. A sealing resin comprising 70 to 95 parts by weight of an inorganic filler in 100 parts by weight of the sealing resin, and 40 to 100 parts by weight of a dicyclopentadiene type epoxy resin in 100 parts by weight of all epoxy resins. In a sealing resin containing parts by weight, the following formula (a) is used as a silane coupling agent.
And a silane compound represented by the following formula (b).

[0009]

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[0010]

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[0011] A sealing resin according to a second aspect of the present invention is the sealing resin according to the first aspect, wherein the inorganic filler contains silica.

According to a third aspect of the present invention, a semiconductor device mounted on a lead frame is sealed by using the sealing resin according to the first or second aspect.

According to the present invention, the silane coupling agents represented by the above formulas (a) and (b) are mixed in the sealing resin, so that the inorganic filler is used in 100 parts by weight of the sealing resin. 70 to 95 parts by weight, and total epoxy resin 1
Even if the sealing resin contains 40 to 100 parts by weight of a dicyclopentadiene-type epoxy resin in 00 parts by weight, these silane coupling agents may cause the adhesion between the inorganic filler and the lead frame, and the moldability. In order to improve the sealing property, it is possible to perform sealing with excellent adhesiveness and moldability between the lead frame and the cured resin.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The sealing resin of the present invention comprises at least a dicyclopentadiene type epoxy resin, a curing agent, an inorganic filler and a silane coupling agent, a silane compound represented by the above formula (a) and a silane coupling agent. A silane compound represented by (b) is blended. It is important that the silane compound represented by the above formula (a) and the silane compound represented by the above formula (b) are blended together, and when these silane coupling agents are not blended or only one of them is used. When it is blended, the adhesion to the lead frame is reduced and the formability is reduced. In addition, among the silane compounds represented by the above formula (a), N-phenyl-γ represented by the following formula (c)
When aminopropyltrimethoxysilane is used and γ-mercaptopropyltrimethoxysilane represented by the following formula (d) is used among the silane compounds represented by the formula (b), the adhesiveness and moldability are improved. The effect of improvement is large and preferable.

[0015]

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[0016]

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The silane coupling agent represented by the above formula (a) and the silane coupling agent represented by the above formula (b) are each added in an amount of 0.05 to 1 with respect to 100 parts by weight of the inorganic filler. 0.5 parts by weight, more preferably 0.1-1.
It is preferable to mix 0 parts by weight. When the amount is less than 0.05 part by weight, the effect of improving the adhesiveness and moldability is small, and when the amount exceeds 1.5 parts by weight, the strength of the cured resin is reduced, which is problematic.

The silane coupling agent is not limited to a mixture of only the silane compound represented by the above formula (a) and the silane compound represented by the above formula (b). If necessary, aminosilanes other than the compound represented by the above formula (a), such as γ-ureidopropyltrimethoxysilane, and epoxysilanes, such as γ-glycidoxypropyltrimethoxysilane, may be added. Good. Also, these silane coupling agents,
The inorganic filler may be added directly to the sealing resin, but the inorganic filler may be sprayed directly onto the inorganic filler in advance, or the inorganic filler may be immersed in a solution in which the silane coupling agent has been dissolved. After the treatment, in the case of adding to the sealing resin, the effect of improving the adhesiveness between the cured resin and the lead frame and improving the moldability are surely compared to the case of adding directly to the sealing resin. It is preferable because it can be obtained.

The inorganic filler used in the present invention is not particularly limited. For example, crystalline silica, amorphous silica, alumina, magnesia, titanium oxide, calcium carbonate, magnesium carbonate, silicon nitride, talc, calcium silicate And the like. The inorganic filler may be used alone or in combination of two or more. It is important that the inorganic filler is contained in an amount of 70 to 95 parts by weight based on 100 parts by weight of the sealing resin. When the amount of the inorganic filler is less than 70 parts by weight, the amount of moisture absorption of the cured resin increases, and the moisture absorption solder heat resistance may decrease, and when the amount exceeds 95 parts by weight, the viscosity of the sealing resin increases, There is a problem that the moldability at the time of sealing is reduced. In addition, it is preferable to use silica such as crystalline silica or amorphous silica as the inorganic filler because the coefficient of linear expansion of the cured resin becomes small and approaches the linear expansion coefficient of the semiconductor element.

It is important that the epoxy resin used in the present invention contains 40 to 100 parts by weight of a dicyclopentadiene type epoxy resin per 100 parts by weight of the total epoxy resin. If the amount is less than 40 parts by weight, the moisture absorption rate may increase and the moisture absorption solder heat resistance may decrease. The dicyclopentadiene type epoxy resin includes, for example, compounds represented by the following formulas (e) and (f). In addition, in Formula (e), p represents 0 or a positive number, and q in Formula (f) represents 0 or a positive number. In addition, the epoxy resin represented by the following formula (e) has a large effect of improving the moisture absorption solder heat resistance, and thus is preferable.

[0021]

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[0022]

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The epoxy resin used in the present invention is not limited to the dicyclopentadiene type epoxy resin alone, and the dicyclopentadiene type epoxy resin should be contained in an amount of 40 parts by weight or more per 100 parts by weight of the total epoxy resin. When blended, for example, cresol novolak type epoxy resin, bisphenol A type epoxy resin, phenol novolak type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin and the like can be used in combination. They may be used alone or in combination of two or more. In addition, it is preferable to use a biphenyl-type epoxy resin in combination, since the moisture absorption solder heat resistance is further improved.

The curing agent used in the present invention is not particularly limited as long as it reacts with an epoxy resin and cures. For example, a phenol novolak resin, a cresol novolak resin, a naphthol novolak resin, an aralkyl type phenol resin, etc. Novolak resins, acid anhydrides such as phthalic anhydride and pyrometic anhydride, and aromatic amines such as diaminodiphenylmethane and metaphenylenediamine. The above-mentioned curing agents may be used alone or in combination of two or more kinds. The amount of the curing agent is usually 0.5 to 1.
It is blended in the range of 5. In addition, when an aralkyl-type phenol resin represented by the following formula (g) is used, the moisture absorption of the resin is low, and thus the moisture absorption solder heat resistance is improved, which is preferable. In the formula (g), r represents 0 or a positive integer. The aralkyl type phenol resin is a resin obtained by reacting a phenol such as phenol or cresol with an aralkyl ether.

[0025]

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The phenol moiety of the aralkyl-type phenolic resin represented by the above formula (g) is α-
When a phenol resin represented by the following formula (h) is contained instead of naphthol, the moisture absorption rate of the resin is low, so that the moisture absorption solder heat resistance is improved, which is preferable. In addition, in Formula (h), s represents 0 or a positive integer.

[0027]

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[0028] The sealing resin of the present invention may contain a curing accelerator, a release agent, a coloring agent, a low stress agent, a flame retardant, and the like, if necessary. As a curing accelerator, for example,
1,8-diaza-bicyclo (5,4,0) undecene-
7, tertiary amine compounds such as triethylenediamine and benzyldimethylamine, imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole and 2-phenyl-4-methylimidazole, triphenylphosphine And organic phosphine compounds such as tributylphosphine.
Examples of the release agent include carnauba wax, stearic acid, montanic acid, and a carboxyl group-containing polyolefin. Examples of the coloring agent include carbon black and titanium oxide. Examples of the low stress agent include silicone gel, silicone rubber, silicone oil and the like. Examples of the flame retardant include antimony trioxide, halogen compounds, phosphorus compounds and the like. Two or more of these curing accelerators, release agents, coloring agents, stress reducing agents, flame retardants and the like can be used in combination.

It is preferable that the sealing resin of the present invention is uniformly mixed and kneaded. As a method of kneading, for example, a sealing resin is manufactured by heating using a roll, a kneader, a mixer, or the like, and then cooling, pulverizing, or the like.

[0030]

【Example】

(Examples 1 to 7, Comparative Examples 1 to 3) As sealing resins, the following three types of epoxy resins, three types of curing agents, three types of silane coupling agents, inorganic fillers, curing accelerators, and coloring agents , A flame retardant and a release agent were blended in the weight ratios shown in Tables 1 and 2.

Epoxy resin a: a dicyclopentadiene type epoxy resin represented by the above formula (e) and having an epoxy equivalent of 260 [HP7200, manufactured by Dainippon Ink Co., Ltd.] Epoxy resin a: an epoxy equivalent of 192 Biphenyl type epoxy resin [YX4000 manufactured by Yuka Shell Co., Ltd.
H] ・ Epoxy resin c: Tetrabromobisphenol A type epoxy resin having an epoxy equivalent of 400 ・ Curing agent f: Hydroxyl equivalent 17 represented by the above formula (g)
0 aralkyl type phenolic resin [Mitsui Toatsu Chemical Co., Ltd.
Trade name: MILEX XL-225-3L] Curing agent: hydroxyl equivalent 21 represented by the above formula (h)
0 phenolic resin [Nippon Steel Chemical Co., Ltd., trade name SN18
0] Curing agent: Phenol novolak resin having a hydroxyl equivalent of 105 [Tamanol 752, manufactured by Arakawa Chemical Co., Ltd.] Silane coupling agent: N represented by the above formula (c)
-Phenyl-γ-aminopropyltrimethoxysilane [manufactured by Shin-Etsu Chemical Co., Ltd., trade name KBM573] • Silane coupling agent: γ represented by the above formula (d)
-Mercaptopropyltrimethoxysilane [manufactured by Toshiba Silicone Co., Ltd., trade name: TSL8380E]-Silane coupling agent: epoxy silane [manufactured by Toray Dow Corning, trade name: SH6040]-Inorganic filler: amorphous silica [Denki Kagaku Kogyo Co., Ltd.] Manufactured and trade name: FB74]-Curing accelerator: triphenylphosphine-Colorant: carbon black-Flame retardant: antimony trioxide-Release agent: carnauba wax

[0032]

[Table 1]

[0033]

[Table 2]

The above-mentioned silane coupling agent was blended after directly spraying it onto an inorganic filler and subjecting it to a surface treatment. After mixing the above respective raw materials, the mixture was kneaded at a temperature of 85 ° C. for 5 minutes using a heating roll, and then cooled. Then, it was pulverized to obtain a sealing resin.

(Evaluation) Using the sealing resins obtained in Examples 1 to 7 and Comparative Examples 1 to 3, an evaluation sample was prepared by the following method, and the evaluation sample was evaluated for adhesion and moldability. ,
The moisture absorption heat resistance and the moisture absorption were measured by the following methods.

The adhesion was determined by forming a pudding-type evaluation sample on one side of a 0.5 mm-thick copper plate having silver plating applied over the entire surface at a temperature of 170 ° C. for 90 seconds using a transfer molding machine. It was made by post-curing at a temperature of ° C for 6 hours. Next, this evaluation sample was pulled in the shearing direction using a push-pull gauge, and the strength at the time of breaking was determined.

The moldability was determined by bonding a 9.6 × 9.6 × 0.4 mm semiconductor element to a 150 μm thick silver plated copper alloy lead frame with a silver paste,
A 19 × 1.8 mm 60-pin QFP type evaluation sample (semiconductor device) was prepared in the same manner as the adhesion evaluation sample. Next, the residual air bubbles inside the ten evaluation samples were measured using an ultrasonic probe (M-70, manufactured by Canon Inc.).
0II) was observed, and those in which bubbles having a diameter of 0.3 mm or more remained were determined as defective.

As for the moisture absorption solder heat resistance, a 60-pin QFP type evaluation sample similar to the moldability evaluation sample was prepared in the same manner. Next, 10 samples for evaluation were subjected to 85 ° C /
After being treated under the condition of 85% RH for 72 hours, it was immersed in 250 ° C. solder for 10 seconds. Next, the evaluation sample was cut in half, and the cut surface was polished, and then the size of cracks was observed with a microscope. Cracks having a size of 75 μm or more were determined to be defective.

The moisture absorption was determined by preparing a disk-shaped evaluation sample having a diameter of 50 mm and a thickness of 3 mm in the same manner as the adhesion evaluation sample, drying at 125 ° C. for 16 hours, and then heating at 85 ° C./85% RH. After processing for 72 hours under the conditions of
The difference from the weight immediately after drying at a temperature of 125 ° C. for 16 hours was measured to calculate the increase rate.

(Results) As shown in Tables 1 and 2, each Example had better adhesion than Comparative Example 1 and each Example had better adhesion than Comparative Examples 2 and 3. In comparison, it was confirmed that the moldability was good. That is, it was confirmed that each of the examples had good adhesion and moldability. In addition, it was confirmed that each example had the same or slightly better moisture absorption solder heat resistance and moisture absorption rate than the comparative examples.

[0041]

According to the first and second aspects of the present invention, the sealing resin contains the silane coupling agents represented by the above formulas (a) and (b). Therefore, even if the sealing resin contains a high ratio of the inorganic filler in the sealing resin, and contains a high ratio of the dicyclopentadiene-type epoxy resin in all the epoxy resins, When sealing is performed using the resin, a sealed product excellent in both the adhesiveness between the lead frame and the cured resin and the moldability can be obtained.

The semiconductor device according to the third aspect of the present invention is a semiconductor device excellent in both adhesiveness and moldability between the lead frame and the cured resin.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H01L 23/31 (56) References JP-A-5-32867 (JP, A) JP-A-7-82341 (JP, A) JP-A-8-20673 (JP, A) JP-A-6-69380 (JP, A) JP-A-5-86265 (JP, A) JP-A-7-242732 (JP, A) JP-A-3-62845 (JP JP, A) JP-A-9-169891 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 63/00-63/10 C08K 3/36 C08K 5/544 C08K 5 / 58 H01L 23/29

Claims (3)

(57) [Claims] 1. An epoxy resin composition for a sealing material comprising an epoxy resin, a curing agent, an inorganic filler and a silane coupling agent, wherein the epoxy resin composition for a sealing material is
In 0 parts by weight, 70 to 95 parts by weight of an inorganic filler is contained,
In addition, an epoxy resin composition for a sealing material containing 40 to 100 parts by weight of a dicyclopentadiene type epoxy resin in 100 parts by weight of all epoxy resins is represented by the following formula (a) as a silane coupling agent. An epoxy resin composition for a sealing material, comprising a silane compound and a silane compound represented by the following formula (b). Embedded image (Wherein R ¹ , R ³ and R ⁴ are hydrogen or a monovalent hydrocarbon group having 1 to 12 carbon atoms, R ² is a divalent hydrocarbon group having 1 to 12 carbon atoms, and n is an integer of 1 to 3) Represents the following.) (Wherein R ⁵ is a divalent hydrocarbon group having 1 to 12 carbon atoms,
R ⁶ and R ⁷ are hydrogen or a monovalent hydrocarbon group having 1 to 12 carbon atoms, and m represents an integer of 1 to 3. ) 2. The epoxy resin composition for a sealing material according to claim 1, wherein the inorganic filler contains silica. 3. A semiconductor device obtained by sealing a semiconductor element mounted on a lead frame using the epoxy resin composition for a sealing material according to claim 1.