JPH1171445A - Epoxy resin composition and semiconductor device sealed therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-reliability composition giving a package reduced in warpage, having good flowability, excellent moldability, free from the formation of resin crack, having good adhesiveness and excellent humidity resistance after mounting, by using a specified epoxy resin and a specified phenolic resin. SOLUTION: This composition essentially consists of an epoxy resin (A) containing a polyfunctional epoxy resin (a) represented by formula I(wherein R<1> , R<2> and R<3> are each hydrogen or a 1-10C alkyl) and an epoxy-modified polybutadiene (b) in an a/b weight ratio of l-100, a polyfunctional phenolic resin (B) represented by formula II (wherein n is 0 or an integer of 1 or greater), an inorganic filler (C) and a cure accelerator (D) and contains component C in an amount of 25-93 wt.% based on the composition. A semiconductor chip is sealed with a cured product of this composition to form a BGA type sealed semiconductor device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an epoxy resin composition excellent in moisture resistance and solder heat resistance, and a BGA (Ball Grid Array) in which a semiconductor chip is sealed with the composition.
) Type semiconductor sealing device.

[0002]

2. Description of the Related Art In recent years, in the field of semiconductor integrated circuits,
While the size and the number of electrodes are increasing with the increase in the degree of integration of chips, the demand for smaller and lighter package outer diameters is increasing, especially for portable information communication devices.

For this reason, the Q in which the leads are
In the case of FP (Quad Flat Package), the narrowing of the pitch due to the increase in the number of electrodes is accelerating and the current pitch is 0.3 mm, which is the limit of batch reflow soldering.

[0004] Therefore, the BGA type in which the leads are arranged in an area array on the lower surface of the package is shifted to an electrode pitch of 1.
Movement to keep solder at 5 mm to 1.0 mm to facilitate soldering has been active mainly in the United States since several years ago.

However, since the BGA type package is sealed on one side, when the package is sealed with a resin composition comprising a conventional novolak type epoxy resin such as a novolak type epoxy resin, a novolak type phenol resin, and silica powder, the package warp. There was a disadvantage of being large. In addition, there is a disadvantage that the wire flows during molding due to the long loop of the bonding wire.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and has a small package warpage, good fluidity, excellent moldability, and a low heat resistance during mounting. To provide an epoxy resin composition and a BGA-type semiconductor encapsulation device that have excellent resistance, have no resin cracks, have good adhesiveness, have excellent moisture resistance after mounting, and guarantee long-term reliability. Is what you do.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, by using a specific epoxy resin and a specific phenol resin,
The inventors have found that a resin composition having excellent moisture resistance and solder heat resistance can be obtained, and have completed the present invention.

That is, the present invention provides (A) and (a) a polyfunctional epoxy resin represented by the following general formula:

[0009]

Embedded image (Wherein, R ¹ , R ² , and R ³ represent a hydrogen atom or a carbon atom
(Representing an alkyl group of 1 to 10) (b) an epoxy resin containing an epoxy-modified polybutadiene in a weight ratio [(a) / (b)] of 1 to 100, and (B) an epoxy resin represented by the following general formula: Polyfunctional phenolic resin,

[0010]

Embedded image (Wherein, n represents an integer of 0 or 1 or more) (C) An inorganic filler and (D) a curing accelerator are essential components, and the (C) inorganic filler is added to the resin composition in an amount of 25%.
An epoxy resin composition characterized in that it is contained in a proportion of up to 93% by weight. Another embodiment of the present invention is a BGA-type semiconductor encapsulation device, wherein a semiconductor chip is encapsulated with a cured product of the epoxy resin composition.

Hereinafter, the present invention will be described in detail.

Among the (A) epoxy resins used in the present invention, as the polyfunctional epoxy resin of the component (a), those represented by the aforementioned general formula 5 are used, and the epoxy-modified polybutadiene of the component (b) is used. Specific brands include E-1800-6.5 and E-1000-6.5 (trade names, manufactured by Nippon Oil Co., Ltd.). As the epoxy resin (A), (a) a polyfunctional epoxy resin and (b) an epoxy-modified polybutadiene are represented by [(a) component / (b)
Component) in a weight ratio of 1 to 100.

The epoxy resin (A) can be used in combination with a novolak epoxy resin, an epibis epoxy resin, and other generally known epoxy resins.

As the polyfunctional phenol resin (B) used in the present invention, those represented by the aforementioned general formula (6) are used. Specific compounds include, for example,

[0015]

Embedded image

[0016]

Embedded image

[0017]

Embedded image And the like.

In addition to the polyfunctional phenol resin, a novolak-type phenol resin obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde, and modified resins thereof can be used in combination.

As the inorganic filler (C) used in the present invention, those generally used are widely used. Among them, silica powder having a low impurity concentration and an average particle diameter of 30 μm or less is preferably used. Can be. If the average particle size exceeds 30 μm, the moisture resistance and the moldability are poor, which is not preferable. The inorganic filler is desirably contained in a proportion of 25 to 93% by weight based on the whole resin composition.
If the proportion is less than 25% by weight, the resin composition has a large hygroscopicity and is inferior in moisture resistance after immersion in solder, and if it exceeds 93% by weight, the fluidity becomes extremely poor and the moldability is inferior.

The (D) curing accelerator used in the present invention includes a phosphorus-based curing accelerator, an imidazole-based curing accelerator,
BU-based curing accelerators and other curing accelerators are widely used. These can be used alone or in combination of two or more. The compounding ratio of the curing accelerator is 0.01% with respect to the resin composition.
It is desirable to mix them so as to contain up to 5% by weight. If the proportion is less than 0.01% by weight, the gel time of the resin composition is long and the curing property is deteriorated. If it exceeds 5% by weight, the fluidity is extremely deteriorated, the moldability is deteriorated, and the electric properties are also deteriorated, and the moisture resistance is deteriorated. Inferior in properties and not preferred.

The epoxy resin composition of the present invention contains the above-mentioned specific epoxy resin, specific phenol resin, inorganic filler and curing accelerator as essential components. Depending on, for example, natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, release agents such as paraffins, flame retardants such as antimony trioxide, carbon black,
A coloring agent such as redwood, a silane coupling agent, a rubber-based or silicone-based low-stress imparting agent, and the like can be appropriately added and blended.

As a general method for preparing the epoxy resin composition of the present invention as a molding material, a specific epoxy resin, a specific phenol resin, an inorganic filler, a curing accelerator, and other components described above are mixed with a predetermined component. After blending the raw material components selected in the composition ratio and mixing sufficiently uniformly with a mixer or the like, further perform a melt mixing treatment with a hot roll or a mixing treatment with a kneader or the like, then solidify by cooling, and pulverize to an appropriate size. It can be a molding material. If the molding material thus obtained is applied to sealing, coating, insulating, etc. of electronic parts or electric parts such as semiconductor devices, excellent properties and reliability can be imparted.

The semiconductor encapsulation device of the present invention can be easily manufactured by encapsulating a semiconductor chip using the above-mentioned molding material. The semiconductor chip to be sealed is not particularly limited to, for example, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, and the like. The most common sealing method is a low-pressure transfer molding method, but sealing by injection molding, compression molding, casting or the like is also possible. The molding material is heated and cured at the time of sealing, and finally a semiconductor sealing device sealed with the cured product is obtained. 150 ° C for curing by heating
It is desirable to cure by heating as described above.

[0024]

The epoxy resin composition and the BGA type semiconductor encapsulation device of the present invention use the specific epoxy resin and the specific phenol resin described above to reduce the water absorption of the resin composition and to improve the thermomechanical properties. Improved low stress properties, eliminates solder cracks after solder immersion and solder reflow,
Deterioration in moisture resistance is reduced.

[0025]

Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, “%” means “% by weight”.

Example 1 6.2% of the epoxy resin of the above formula 5, 0.5% of epoxy-modified polybutadiene, and 4.8 of the phenol resin of the above formula 7
%, Silica powder 88%, curing accelerator 0.3%, ester wax 0.3% and silane coupling agent 0.4% are mixed at room temperature, kneaded at 90-95 ° C, and cooled and pulverized to form a molding material (A). Was manufactured.

Example 2 6.6% of the epoxy resin of Chemical formula 5 used in Example 1, 0.5% of epoxy-modified polybutadiene, 3.1% of the phenol resin of Chemical formula 7 used in Example 1, and 1.3 of phenol novolak resin
%, Silica powder 88%, curing accelerator 0.3%, ester wax 0.3% and silane coupling agent 0.4% are mixed at room temperature, further kneaded at 90-95 ° C, and cooled and pulverized to form a molding material (B). Was manufactured.

Comparative Example 1 7% of o-cresol novolak type epoxy resin, 4% of novolak type phenol resin, 88% of silica powder, 0.3% of curing accelerator, 0.3% of ester wax and 0.4% of silane coupling agent were mixed. The mixture was kneaded at 90 to 95 ° C and cooled and pulverized to produce a molding material (C).

Comparative Example 2 Epibis epoxy resin 9%, novolak phenol resin 2%, silica powder 88%, curing accelerator 0.3%, ester wax 0.3% and silane coupling agent 0.4%
Were mixed and kneaded at 90 to 95 ° C., and the mixture was cooled and pulverized to produce a molding material (D).

The molding materials (A) to (D) thus produced
Was used to transfer and inject into a mold heated to 175 ° C. and cured to seal the semiconductor chip, thereby producing a semiconductor sealing device. Various tests were performed on these semiconductor sealing devices, and the results are shown in Table 1. The epoxy resin composition and the semiconductor sealing device of the present invention are excellent in moisture resistance and solder heat resistance. The remarkable effect of the invention could be confirmed.

[0031]

[Table 1] * 1: A molded product with a diameter of 50 mm and a thickness of 3 mm was prepared by transfer molding, left in saturated steam at 127 ° C. and 2.5 atm for 24 hours, and measured by the increased weight. * 2: A molded product similar to that in the case of water absorption was prepared, post-cured at 175 ° C for 8 hours, and a test piece of appropriate size was measured using a thermomechanical analyzer. * 3: Tested according to JIS-K-6911. * 4: Using a molding material, a silicon chip with two aluminum wires is bonded to a normal 42 alloy frame, transfer molded at 175 ° C for 2 minutes, and post-cured at 175 ° C for 8 hours. Was. The molded article thus obtained was previously subjected to a moisture absorption treatment at 40 ° C., 90% RH and 100 hours, and then immersed in a solder bath at 250 ° C. for 10 seconds. After that, a humidity resistance test was performed in saturated steam at 127 ° C and 2.5 atm to evaluate the time at which 50% disconnection (defect occurrence) due to aluminum corrosion occurred. * 5: An 8 × 8 mm dummy chip is placed in a BGA (27 × 27 × 1.2 mm) package, transfer molded at 175 ° C for 2 minutes using molding materials, and post-cured at 175 ° C for 8 hours. Was. The semiconductor sealing device thus manufactured was subjected to a moisture absorption treatment at 85 ° C. and 85% for 24 hours, and then immersed in a solder bath at 240 ° C. for 1 minute. Then, the surface of the package was oversold with a stereoscopic microscope, and the presence or absence of external resin cracks was evaluated. * 6: A 10 × 10 mm dummy chip was placed in a BGA (30 × 30 × 1.2 mm) package, transfer-molded using a molding material at 175 ° C. for 2 minutes, and post-cured at 175 ° C. for 8 hours. . The amount of warpage of the semiconductor sealing device manufactured in this manner was measured by a non-contact laser measuring machine.

[0032]

As is apparent from the above description and Table 1, the epoxy resin composition and the BGA type semiconductor encapsulation device of the present invention have a small package warpage, good flowability, and excellent moldability. In addition, it has excellent solder heat resistance during mounting, has no resin cracks, has good adhesiveness, and has excellent moisture resistance after mounting, and can guarantee reliability for a long period of time.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C08K 3/36 H01L 23/30 R 7/18

Claims (2)

[Claims] (A) (a) a polyfunctional epoxy resin represented by the following general formula: (Wherein, R ¹ , R ² , and R ³ represent a hydrogen atom or a carbon atom
(Representing an alkyl group of 1 to 10) (b) an epoxy resin containing an epoxy-modified polybutadiene in a weight ratio [(a) / (b)] of 1 to 100, and (B) an epoxy resin represented by the following general formula: Polyfunctional phenolic resin, (Wherein, n represents an integer of 0 or 1 or more) (C) An inorganic filler and (D) a curing accelerator are essential components, and the (C) inorganic filler is added to the resin composition in an amount of 25%.
An epoxy resin composition characterized in that it is contained in a proportion of up to 93% by weight. (A) (a) a polyfunctional epoxy resin represented by the following general formula: (Wherein, R ¹ , R ² , and R ³ represent a hydrogen atom or a carbon atom
(Representing an alkyl group of 1 to 10) (b) an epoxy resin containing an epoxy-modified polybutadiene in a weight ratio [(a) / (b)] of 1 to 100, and (B) an epoxy resin represented by the following general formula: Polyfunctional phenolic resin, (Wherein, n represents an integer of 0 or 1 or more) (C) An inorganic filler and (D) a curing accelerator are essential components, and the (C) inorganic filler is added to the resin composition in an amount of 25%.
BG characterized in that a semiconductor chip is sealed with a cured product of an epoxy resin composition containing at a ratio of up to 93% by weight.
A-type semiconductor sealing device.