JPH0925330A - Epoxy resin composition and semiconductor device sealed therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition having excellent soldering-heat resistance and mold release and not forming any mold deposits by mixing an epoxy resin with a specified cyclopentadiene/phenolic polymer, an inorganic filler and a cure accelerator as the essential components. SOLUTION: This epoxy resin composition consists essentially of an epoxy resin, a cyclopentadiene/phenol polymer represented by the formula (wherein (n) is 0 or an integer of 1 or greater) and containing previously dispersed polyethylene and ester waxes, 25-90wt.%, based on the resin composition, inorganic filler and a cure accelerator.

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 excellent in solder heat resistance and mold releasability and free from mold stains, and a semiconductor sealing device.

[0002]

2. Description of the Related Art In recent years, in the field of semiconductor integrated circuits,
At the same time as technology development for high integration and high reliability, automation of the mounting process of semiconductor devices is being promoted. For example, when mounting a flat package type semiconductor device on a circuit board,
Conventionally, soldering was performed for each lead pin, but recently, a method of immersing the entire semiconductor device in a solder bath heated to 200 ° C. or higher and performing soldering at once has been adopted.

[0003]

A semiconductor device sealed with a resin composition comprising a conventional epoxy resin such as a novolak type epoxy resin, a novolak type phenol resin and an inorganic filler is subjected to solder bath immersion of the entire device. There is a disadvantage that the moisture resistance is reduced. Especially when a semiconductor device that has absorbed moisture is immersed in a solder bath, peeling occurs between the encapsulating resin and the semiconductor chip, or the encapsulating resin and the lead frame, causing a significant deterioration in moisture resistance, and breaking due to electrode corrosion and leakage due to moisture. There is a drawback in that current is generated and long-term reliability cannot be guaranteed.

From the above, attempts have been made to introduce a hydrophobic and flexible phenol resin curing agent such as cyclopentadiene / phenol resin in order to reduce the moisture absorption of the entire resin composition. As compared with the case where the type phenol resin is used as the curing agent, there is a drawback that the moldability and the mold releasability are inferior. When a small amount of heat-resistant polyethylene wax is blended to improve the mold releasability, the mold releasability is greatly improved, but the polyethylene wax is originally incompatible with the epoxy resin and phenol resin. Since it is a molten metal, it has a drawback that it is gradually deposited on the mold and stains the mold.

The present invention has been made in order to solve the above-mentioned drawbacks, and has high heat resistance and little influence of moisture absorption,
In particular, even if the entire semiconductor device is immersed in a solder bath, there is little deterioration in moisture resistance, excellent solder heat resistance and mold releasability, and there is no peeling between the sealing resin and the semiconductor chip or the sealing resin and the lead frame. The present invention aims to provide an epoxy resin composition and a semiconductor encapsulation device capable of ensuring long-term reliability with good moldability, without causing wire breakage due to electrode corrosion and leak current due to moisture, without causing mold contamination. is there.

[0006]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above object, the present inventor has found that a specific phenol resin in which a polyethylene wax and an ester wax are pre-dispersed in advance is used. , Found that a resin composition that can achieve the above objects is obtained,
The present invention has been completed.

That is, the present invention provides (A) an epoxy resin, (B) a cyclopentadiene / phenol polymer represented by the following formula, in which a polyethylene wax and an ester wax are preliminarily dispersed,

[0008]

Embedded image (However, n represents 0 or an integer of 1 or more in the formula) (C) An inorganic filler and (D) a curing accelerator are essential components, and the above (C) is used for the entire resin composition.
An epoxy resin composition comprising the inorganic filler of 25 to 90% by weight. A semiconductor sealing device is characterized in that a semiconductor chip is sealed with a cured product of the epoxy resin composition.

Hereinafter, the present invention will be described in detail.

As long as the epoxy resin (A) used in the present invention is a compound having at least two epoxy groups in its molecule, it is not particularly limited in molecular weight, structural formula, etc. The used one can be widely used. For example, bisphenol-based epoxy resin, epibis-based epoxy resin, biphenyl-based epoxy resin, novolac-based epoxy resin, and the like,
These epoxy resins can be used alone or in combination of two or more.

As the cyclopentadiene / phenol polymer (B) used in the present invention, the one represented by the above chemical formula 3 is used. This cyclopentadiene / phenol polymer is obtained by preliminarily dispersing a polyethylene wax and an ester wax. Examples of the polyethylene wax to be preliminarily dispersed include linear or branched polyethylene waxes having a carboxy group in the molecule, and these may be used alone or in combination. Examples of ester waxes include natural ester waxes such as carnauba wax (principal component myrisyl cerotate) and synthetic ester waxes such as montanic acid wax, which may be used alone or in combination. What is most important here is that the polyethylene wax and the ester wax are used together and pre-dispersed. For the predispersion, the cyclopentadiene / phenol polymer is melted at 120 to 150 ° C. to disperse the polyethylene wax and the ester wax. The method of dispersion is not particularly limited. In addition to the cyclopentadiene / phenol polymer, a phenol novolac resin, a phenol aralkyl resin, and other resins having two or more phenolic hydroxyl groups in the molecule can be used in combination within the scope of the present invention.

As the inorganic filler (C) used in the present invention, those generally used are widely used, and among them, those having a low impurity concentration are preferably used. Specific examples include silica powder, alumina powder, antimony trioxide, talc, calcium carbonate,
Titanium white, clay, mica, red iron oxide, glass fiber and the like can be mentioned, and these can be used alone or in combination of two or more kinds. Among these, silica powder and alumina powder are particularly preferably used. The blending ratio of the inorganic filler is preferably 25 to 90% by weight based on the total resin composition. If the proportion is less than 25% by weight, the heat resistance, moisture resistance, solder heat resistance, mechanical properties and moldability will be poor, and if it exceeds 90% by weight, the fluidity will be extremely poor and moldability will be poor, such being undesirable.

As the (D) curing accelerator used in the present invention,
Phosphorus curing accelerator, imidazole curing accelerator, DBU
A wide range of system hardening accelerators and other hardening accelerators can be used. These can be used alone or in combination of two or more. It is desirable that the curing accelerator is blended in an amount of 0.01 to 5% by weight based on the total resin composition. If the proportion is less than 0.01% by weight, the gel time of the resin composition will be long and the curing characteristics will be poor, and if it exceeds 5% by weight, the fluidity will be extremely poor and the moldability will be poor, and the electrical characteristics will be poor and the moisture resistance will be poor. It is inferior in sex and is not preferable.

The epoxy resin composition of the present invention contains an epoxy resin, a wax predispersed cyclopentadiene / phenol polymer, an inorganic filler and a curing accelerator as essential components, but within a range not deviating from the object of the present invention, If necessary, for example, a flame retardant such as chlorinated paraffin, brominated toluene, hexabromobenzene, antimony trioxide and the like, and a colorant such as carbon black and red iron oxide can be appropriately added and blended.

A general method for preparing the epoxy resin composition of the present invention as a molding material is to mix an epoxy resin, a wax predispersed cyclopentadienephenol polymer, an inorganic filler, a curing accelerator and other components with a mixer. Mix thoroughly evenly. Further, a melt mixing treatment with a hot roll or a mixing treatment with a kneader or the like is performed, and then the mixture is cooled and solidified and crushed to an appropriate size to obtain a molding material. The molding material thus obtained is
When applied to sealing, coating, insulating, and the like of electronic components or electric components such as semiconductor devices, excellent characteristics 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. As a semiconductor chip for sealing, for example, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, and the like are not particularly limited. 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. After sealing with a molding material, it is heated and cured, and finally a semiconductor sealing device sealed with this cured product is obtained. The curing by heating is desirably performed by heating to 150 ° C. or more.

[0017]

The epoxy resin composition and the semiconductor encapsulation device of the present invention use a cyclopentadiene / phenol polymer in which a polyethylene wax and an ester wax are predispersed to reduce the moisture absorption of the resin composition, It is possible to improve mechanical properties and low stress, eliminate the occurrence of resin cracks after immersion in a solder bath and solder reflow, reduce mold stains, and obtain good mold releasability.

[0018]

EXAMPLES The present invention will now 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”. [Pre-dispersion of waxes] 8.4% of the cyclopentadiene-phenol polymer shown in Chemical formula 3 above was mixed with 0.1% of a linear polyethylene oxide wax (acid value 20, molecular weight 9,000).
5% of carnauba wax and 0.25% of carnauba wax were melt mixed at a temperature of 120 ° C. for 30 minutes to prepare a cyclopentadiene / phenol polymer [preliminarily dispersed phenol resin] in which waxes were predispersed.

Example o-cresol novolac epoxy resin 9.3%, tetrabromobisphenol A type epoxy resin 1.0%, predispersed phenol resin 8.8%, fused silica powder (maximum particle size 100
78%, triphenylphosphine 0.2%, silane coupling agent 0.4%, carbon black 0.3%, antimony trioxide 2.0% are mixed at room temperature and then 90-100
After kneading and cooling at 0 ° C., it was pulverized to produce a molding material (A).

Comparative Example 1 o-cresol novolac epoxy resin 9.3%, tetrabromobisphenol A type epoxy resin 1.0%, cyclopentadiene / phenol polymer 8.4%, linear type polyethylene oxide wax (acid value 20, molecular weight 9,000) 0.15% ,
Carnauba wax 0.25%, fused silica powder 78%, triphenylphosphine 0.2%, silane coupling agent 0.4
%, Carbon black 0.3%, antimony trioxide 2.0%
After mixing at room temperature and kneading and cooling at 90-100 ° C,
The material was crushed to produce a molding material (B).

Comparative Example 2 o-cresol novolac epoxy resin 9.3%, tetrabromobisphenol A type epoxy resin 1.0%, cyclopentadiene / phenol polymer 8.4%, carnauba wax 0.4%, fused silica powder 78%, triphenylphosphine 0.2% , Silane coupling agent 0.4%, carbon black 0.3%, antimony trioxide 2.0% are mixed at room temperature,
Further, after kneading and cooling at 90 to 100 ° C., it was pulverized to produce a molding material (C).

Comparative Example 3 o-cresol novolac epoxy resin 11.4%, tetrabromobisphenol A type epoxy resin 1.0%, novolac type phenol resin 6.3%, carnauba wax 0.4%,
Fused silica powder 78%, triphenylphosphine 0.2%,
Silane coupling agent 0.4%, carbon black 0.3
%, Antimony trioxide 2.0% are mixed at room temperature and then 90%
After kneading and cooling at -100 ° C, it was pulverized to produce a molding material (D).

Molding materials (A) to (D) produced in this way
Was used to transfer transfer into a mold heated to 170 ° C., and the semiconductor chip was sealed and cured to manufacture a semiconductor sealing device. Various tests were conducted on these semiconductor encapsulation devices, and the results are shown in Table 1. The epoxy resin composition and the semiconductor encapsulation device of the present invention are excellent in various characteristics, and the remarkable features of the present invention. I was able to confirm the effect.

[0024]

[Table 1] * 1: Molded product 4 is molded using the test mold consisting of the three die parts 1, 2, and 3 shown in Fig. 1 (a), and then Fig. 1 (b).
As described above, the load when the molded product 4 was removed from the template 2 immediately after the molding was measured, and the small load was marked with ◯ and the large load was marked with x. * 2: DIP16PIN (mirror surface) after 2000 shots continuous molding was evaluated as ◯ when there was no stain on the mold, Δ when slightly soiled, and X when severely soiled. * 3: A test piece of a molded product 4 in which a copper frame 5 is closely adhered to the lower part is molded by a test mold including the three die parts 1, 2, and 3 shown in FIG. The load in the shearing direction when the molded product 4 was peeled from the frame 5 as in (b) was measured, and a large load was ◯, a medium load was Δ, and a small load was ×. * 4: VQFP (12 x 12 mm) with a 5.3 x 5.3 mm semiconductor chip
X 1.4mm) 175 using a molding material
After transfer molding for 2 minutes at ℃, post-curing was performed at 175 ℃ for 8 hours. The semiconductor sealing device obtained in this way was
Moisture absorption treatment was performed at ℃, 85% for 48 hours, and this was passed through an air reflow machine (Max 240 ℃) to investigate the presence of external and internal cracks.

[0025]

As is clear from the above description and Table 1, the epoxy resin composition and the semiconductor encapsulation device of the present invention are less affected by moisture absorption, and have excellent moisture resistance and solder heat resistance even after immersion in a solder bath. It is excellent, and it is possible to remarkably reduce disconnection due to electrode corrosion and generation of leak current due to moisture, and moreover, reliability can be guaranteed for a long period of time. Further, there was no mold stain after continuous molding, and good mold releasability was exhibited.

[Brief description of drawings]

FIG. 1 (a) is a schematic cross-sectional view of a mold for testing the mold releasability of an epoxy resin composition of the present invention, and FIG. 1 (b) is a template perspective view illustrating a releasability evaluation method. is there.

FIG. 2 (a) is a schematic cross-sectional view of a mold for testing the frame adhesion of the epoxy resin composition of the present invention, FIG. 2 (b).
[Fig. 3] is a perspective view of a test piece for explaining an adhesion evaluation method.

[Explanation of symbols]

 1,2,3 Mold 4 Molded product 5 Copper frame

Claims (2)

[Claims] 1. A cyclopentadiene-phenol polymer represented by the following formula, wherein (A) an epoxy resin, (B) a polyethylene wax and an ester wax are predispersed, and (However, n represents 0 or an integer of 1 or more in the formula) (C) An inorganic filler and (D) a curing accelerator are essential components, and the above (C) is used for the entire resin composition.
An epoxy resin composition, characterized by containing the inorganic filler according to the above in a proportion of 25 to 90% by weight. 2. A cyclopentadiene / phenol polymer represented by the following formula, in which (A) an epoxy resin, (B) a polyethylene wax and an ester wax are pre-dispersed, (However, n represents 0 or an integer of 1 or more in the formula) (C) An inorganic filler and (D) a curing accelerator are essential components, and the above (C) is used for the entire resin composition.
A semiconductor encapsulation device, wherein a semiconductor chip is encapsulated with a cured product of an epoxy resin composition containing the inorganic filler in a proportion of 25 to 90% by weight.