JP2000256439A - Resin composition for sealing and apparatus for sealing semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition excellence in moisture resistance, anti- reflowability, formability and long-term reliability by mixing an epoxy resin having a dicyclopentadienyl skeleton, a phenol resin having a methylcyclohexane skeleton and a specific amount of an inorganic filler. SOLUTION: An epoxy resin and a phenol resin to be used in the present invention are represented by formulas II and III, respectively and an inorganic filler is mixed with the resins, the amount of the filler being 25-95 wt.% of the total weight of a composition (wherein in formula I n is an integer of 0 or not less than 1; and in formula II R is represented by formula III). The inorganic filler preferably has a low content of impurities, the maximum particle diameter of not more than 100 μm and an average particle diameter of not more than 30 μm. Such example includes silica powder, alumina powder, silicon nitride powder, antimony trioxide, tale, calcium carbonate, titanium white, clay, mica, red iron oxide, glass fiber and the like among which silica powder and alumina powder are particularly preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to moldability, workability,
The present invention relates to a sealing resin composition and a semiconductor sealing device having excellent reflow resistance and reliability.

[0002]

2. Description of the Related Art In recent years, in the field of semiconductor integrated circuits,
At the same time as the development of high integration and high reliability technologies, automation of the mounting process of semiconductor devices has been promoted. For example, when a flat package type semiconductor device is mounted on a circuit board, soldering has conventionally been performed for each lead pin. Recently, however, the entire semiconductor device has been passed through an infrared (IR) reflow furnace heated to a maximum of 240 ° C. A method of performing solder pickling has been adopted.

[0003]

A semiconductor device encapsulated 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 requires surface mounting of the entire device by IR reflow. There is a drawback that the moisture resistance is reduced when performing.
In particular, when the semiconductor device that has absorbed moisture is subjected to IR reflow, peeling between the sealing resin and the semiconductor chip, or between the sealing resin and the lead frame, and internal cracking of the resin occur, causing significant deterioration of moisture resistance, causing disconnection due to electrode corrosion and disconnection. Leakage current occurs due to moisture, and as a result, the semiconductor device has a drawback that long-term reliability cannot be guaranteed.
For this reason, there has been a strong demand for the development of a material which has little influence on moisture resistance and has good moldability with little moisture resistance deterioration even if surface mounting by IR reflow of a semiconductor device is performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages, and has a small influence of moisture absorption. In particular, it has excellent moisture resistance, reflow resistance, and moldability after surface mounting by IR reflow, and has excellent sealing resin. There is no peeling between the semiconductor chip or the sealing resin and the lead frame, no internal resin cracks, no disconnection due to electrode corrosion, no leakage current due to moisture, and a sealing resin that can guarantee long-term reliability It is an object to provide a composition and a semiconductor sealing device.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that by using a specific epoxy resin and a specific phenol resin, moisture resistance, IR reflow resistance, The inventors have found that a resin composition excellent in moldability, workability and the like can be obtained, and have completed the present invention.

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

Embedded image (Where n represents an integer of 0 or 1 or more) (B) a phenolic resin represented by the following general formula:

Embedded image (C) an inorganic filler, which is an essential component, and contains the inorganic filler (C) in a proportion of 25 to 95% by weight based on the entire resin composition. Things. Further, there is provided a semiconductor sealing device wherein a semiconductor chip is sealed with a cured product of the sealing resin composition.

Hereinafter, the present invention will be described in detail.

The epoxy resin (A) used in the present invention comprises:
An epoxy resin having a skeleton containing dicyclopentadiene represented by the general formula 5 is used. In addition, a novolak epoxy resin, an epibis epoxy resin, and other commonly known epoxy resins can be used in combination with the epoxy resin.

As the phenolic resin (B) used in the present invention, a phenolic resin having a skeleton of methylcyclohexane represented by the above general formula 6 can be used. As the phenol resin (B), a known phenol resin having two or more phenolic hydroxyl groups in a molecule that can react with an epoxy group of the epoxy resin can be used in combination, as long as the properties are not impaired.

The inorganic filler (C) used in the present invention has a low impurity concentration, a maximum particle size of 100 μm or less,
An inorganic filler having an average particle size of 30 μm or less is preferably used. If the average particle size exceeds 30 μm, the moisture resistance and the moldability are poor, which is not preferable. Specific examples of the inorganic filler include, for example, silica powder, alumina powder, silicon nitride powder, antimony trioxide, talc, calcium carbonate, titanium white, clay, mica, red iron oxide, glass fiber, and the like. They can be used alone or in combination of two or more. Among these, silica powder and alumina powder are particularly preferable and are often used. The mixing ratio of the inorganic filler is 25 to the entire resin composition.
It is desirable to contain it at a ratio of about 95% by weight. If the proportion is less than 25% by weight, heat resistance, moisture resistance, solder heat resistance,
Poor mechanical properties and moldability, and 95% by weight
If it exceeds, the burrs become large and the moldability is inferior and is not suitable for practical use.

The encapsulating resin composition of the present invention contains the above-mentioned specific epoxy resin, specific phenol resin and inorganic filler as essential components. Release agents such as natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, paraffins, chlorinated paraffins, brominated toluene, hexabromobenzene, antimony trioxide, etc. Flame retardants, coloring agents such as carbon black and red iron, rubber-based and silicone-based low-stress imparting agents, and the like can be appropriately added and blended.

A general method for preparing the encapsulating resin composition of the present invention as a molding material is to mix the specific epoxy resin, the specific phenol resin, the inorganic filler and other components described above, and mix them with a mixer or the like. After sufficient uniform mixing, the mixture is further subjected to a melt-mixing treatment using a hot roll, and then cooled and solidified, and pulverized to an appropriate size to obtain 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.

Further, the semiconductor encapsulating apparatus 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. After sealing with a molding material, it is heated and cured, and finally a semiconductor sealing device sealed with a cured product of this composition is obtained. Curing by heating is 1
It is desirable to cure by heating to 50 ° C. or higher.

[0014]

The resin composition for encapsulation and the semiconductor encapsulation device of the present invention use the above-mentioned specific epoxy resin containing dicyclopentadiene in the skeleton and the specific phenol resin containing methylcyclohexane in the skeleton. In addition, the moldability of the resin composition and the adhesive strength with the frame were improved, and the reflow resistance was able to be significantly improved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described specifically 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 Epoxy resin represented by the above formula (epoxy equivalent: 265)
7.6%, 5.4% of the phenol resin shown in Chemical formula 6 (phenol equivalent: 155) and 0.1% of triphenylphosphine.
1%, fused silica powder 85% and ester waxes 1.9% were mixed at room temperature, kneaded and cooled at 90 to 95 ° C, and then pulverized to produce a molding material (A).

Example 2 Epoxy resin represented by the above formula (epoxy equivalent: 265)
5.9%, 4.1% of the phenol resin shown in Chemical formula 6 (phenol equivalent: 155), 0.1% of triphenylphosphine.
1%, 87% of fused silica powder and 1.9% of ester waxes were mixed at room temperature, kneaded and cooled at 90 to 95 ° C, and then pulverized to produce a molding material (B).

Comparative Example 1 8.4% of o-cresol novolak epoxy resin (epoxy equivalent: 195), 4.6% of novolak type phenol resin (phenol equivalent: 107), 85% of fused silica powder,
0.1% triphenylphosphine, 0.3% ester-based wax and 0.4% silane-based coupling agent are mixed at room temperature, kneaded and cooled at 90 to 95 ° C, and then pulverized to form a molding material (C ) Manufactured.

Comparative Example 2 Biphenyl type epoxy resin (epoxy equivalent: 193) 5.
3%, aralkyl phenol resin (phenol equivalent 17
5) 4.7%, fused silica powder 88%, triphenylphosphine 0.1% and ester waxes 1.1%
Was mixed at room temperature, kneaded and cooled at 90 to 95 ° C., and then pulverized to produce a molding material (D).

Using the molding materials prepared in Examples 1 and 2 and Comparative Examples 1 and 2, transfer molding was performed at 175 ° C. for 2 minutes, and after-curing was performed at 175 ° C. for 8 hours to prepare test pieces. For these molding materials and test specimens, moldability, spiral flow, melt viscosity by Koka type flow tester, water absorption (under PCT conditions), glass transition temperature, bond strength with 42 alloy and copper alloy as frame materials The PCT and the reflow resistance were measured. The results of the above measurements are shown in Table 1, and a remarkable effect of the present invention could be confirmed.

[0021]

[Table 1] * 1: Measurement temperature of spiral and melt viscosity is 175 ° C.

* 2: The molding material was transfer-molded at 175 ° C. for 2 minutes, and after-cured at 175 ° C. for 8 hours to produce a molded product. This was allowed to stand in saturated steam at 127 ° C. and 2 atm for 24 hours, and the weight was increased.

* 3: From the same molded article as in the test for water absorption,
2.5mm × 2.5mm × 15.0mm-20.0mm
A sample with the dimensions of
00H (trade name, manufactured by Vacuum Riko Co., Ltd.) at a heating rate of 5 ° C.
/ Min.

* 4: Using a molding material, a silicon chip having two or more aluminum wires
After bonding to an alloy frame and transfer molding at 175 ° C. for 2 minutes, post-curing was performed at 175 ° C. for 8 hours.
The molded product thus obtained was previously prepared at 40 ° C., 90% RH, 10
After the moisture absorption treatment for 0 hour, the substrate was immersed in a solder bath at 250 ° C. for 10 seconds. Thereafter, a moisture resistance test is performed in saturated steam at 127 ° C. and 2.5 atm.
The time at which disconnection (occurrence of a defect) occurred was evaluated.

* 5: The molding material was sealed at 175 ° C. for 2 minutes to seal a 15 mm × 15 mm element for evaluation.
After-curing was performed at 8 ° C. for 8 hours. Next, the package was left in an atmosphere at 85 ° C. and a relative humidity of 60% for 168 hours to perform a moisture absorption treatment.
Passed through an IR reflow oven at 3 ° C. three times. At this point, the occurrence of cracks in the package was examined. Further, the package after the IR reflow was left in a saturated steam atmosphere at 127 ° C. for 100 to 1000 hours in a pressure cooker, and the occurrence rate of defects was examined.

[0026]

As apparent from the above description and Table 1, the encapsulating resin composition and the semiconductor encapsulating apparatus of the present invention are excellent in reflow resistance and moisture resistance, and are affected by moisture absorption even after IR reflow. In addition, disconnection due to electrode corrosion and occurrence of leakage current due to moisture can be significantly reduced, and reliability can be guaranteed for a long period of time.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08K 3/36 C08K 3/36 7/14 7/14 C08L 63/00 C08L 63/00 Z H01L 23/29 H01L 23 / 30 R 23/31 F term (reference) 4J002 CD001 CD041 DE117 DE127 DE137 DE147 DE237 DJ007 DJ017 DJ037 DJ047 DJ057 DL007 EJ046 FA047 FD017 FD146 GQ05 4J036 AD11 AE07 DB10 FA05 FA06 JA07 4M109 AA01 CA21 EA04 EB03 EC03 EC03 EC03 EC05

Claims (2)

[Claims] (A) an epoxy resin represented by the following general formula: (Wherein, n represents 0 or an integer of 1 or more). (B) A phenol resin represented by the following general formula: (C) an inorganic filler, which is an essential component, and contains the inorganic filler (C) in a proportion of 25 to 95% by weight based on the entire resin composition. object. (A) an epoxy resin represented by the following general formula: (Wherein, n represents 0 or an integer of 1 or more). (B) A phenol resin represented by the following general formula: (C) Inorganic filler is an essential component, and the cured product of the encapsulating resin composition containing the inorganic filler of (C) at a ratio of 25 to 95% by weight based on the whole resin composition is used to obtain a semiconductor. A semiconductor sealing device, wherein a chip is sealed.