JPH0753672A - Epoxy resin composition and sealed semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the subject composition, excellent in heat and solder heat resistances, hardly being influenced due to moisture absorption, and useful as sealed semiconductor devices by modifying a specific epoxy resin and a phenol resin as a curing agent with a specific polyimide resin. CONSTITUTION:This resin composition contains (A) an epoxy resin expressed by formula I[R<1> is CjH2j+1; R<2> is CkH2k+1; R<3> is C1H21+1; R<4> is CmH2m+1; (j), (k), (l), (m) and (n) are 0 or integers of >=1[, e.g. a compound expressed by formula II (t-Bu is tert-butyl), (B) a phenol resin, (C) a polyimide resin expressed by formula III (R<5> is C1H21+1; R<6> is CmH2m+1), e.g. a compound expressed by formula IV and (D) an inorganic filler, e.g. silica powder having <=30mum average particle diametr as essential components. The component (D) is contained in an amount of 25-90wt.% based on the resin composition.

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 having excellent moisture resistance and solder heat resistance, and a semiconductor encapsulation device in which a semiconductor chip is encapsulated with the composition.

[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, each lead pin has been soldered, but recently, a solder dipping method or a solder reflow method has been adopted.

A conventional semiconductor device sealed with a resin composition comprising an epoxy resin such as a novolac type epoxy resin, a novolac type phenol resin and silica powder has a drawback that the moisture resistance is lowered when the entire device is immersed in a solder bath. was there. Especially when a semiconductor device that has absorbed moisture is immersed, peeling between the encapsulating resin and the semiconductor chip, or the encapsulating resin and the lead frame, and internal resin cracking cause significant moisture resistance deterioration, which may cause wire breakage or moisture due to corrosion of the electrodes. A leak current is generated, and as a result, the semiconductor device has a drawback that it cannot guarantee long-term reliability.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks and has little influence of moisture absorption, and particularly excellent moisture resistance and solder heat resistance after immersion in a solder bath, and a sealing resin. Epoxy resin composition and semiconductor capable of ensuring long-term reliability without peeling between the semiconductor chip or the encapsulating resin and the lead frame and the occurrence of internal resin cracks, and without the occurrence of wire breakage due to electrode corrosion or leak current due to moisture. It is intended to provide a sealing device.

[0005]

As a result of intensive studies aimed at achieving the above-mentioned object, the present inventors have used a phenol resin as a curing agent for a specific epoxy resin and modified it with a specific polyimide resin. Moisture resistance,
The present invention has been completed by finding that a resin composition having excellent solder heat resistance can be obtained.

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

[0007]

[Chemical 5] (However, in the formula, R ¹ is a C _j H _{2j + 1} group, and R ² is C _k H _{2k + 1.}
R ³ represents a C ₁ H _{2l + 1} group, R ⁴ represents a C _m H _{2m + 1} group, and j, k, l, m and n in each group are 0.
Or represents an integer of 1 or more) (B) Phenolic resin (C) Polyimide resin represented by the following general formula and

[0008]

[Chemical 6] (However, in the formula, R ⁵ is a C ₁ H _{2l + 1} group, and R ⁶ is a C _m H _{2m + 1 group.}
Each represents a group, and l and m in each group represent 0 or an integer of 1 or more) (D) The inorganic filler is an essential component, and the resin composition contains 25 to 90 parts by weight of the (D) inorganic filler. % Of the epoxy resin composition. A semiconductor encapsulation device is obtained by encapsulating a semiconductor chip with a cured product of this epoxy resin composition.

The present invention will be described in detail below.

As the epoxy resin (A) used in the present invention, the one represented by the above-mentioned formula 5 is used, and it can be used without any particular limitation on the molecular weight and the like.
As a specific compound, for example,

[0011]

[Chemical 7] (However, in the formula, t-Bu is a tert-butyl group, and n is 0 or 1
Represents the above integers)

[0012]

[Chemical 8] (However, in the formula, n represents 0 or an integer of 1 or more)

[0013]

[Chemical 9] (However, in the formula, t-Bu is a tert-butyl group, and n is 0 or 1
Represents the above integers), etc., and these may be used alone or
Two or more kinds can be mixed and used. Further, a novolac type epoxy resin, an epibis type epoxy resin, and other generally known epoxy resins can be used in combination with these epoxy resins.

The (B) phenolic resin used in the present invention is not particularly limited, and a novolac type phenolic resin obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde and their modifications. Resins or other generally known phenolic resins can be used.

As the (C) polyimide resin used in the present invention, those represented by the above general formula can be used. Specific compounds include, for example:

[0016]

[Chemical 10] Etc. can be mentioned.

As the inorganic filler (D) 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. You can If the average particle size exceeds 30 μm, the moisture resistance and moldability are poor, which is not preferable. The blending ratio of the inorganic filler is based on the resin composition.
It is desirable that the content is 25 to 90% by weight. If the proportion is less than 25% by weight, the hygroscopicity of the resin composition is large,
Moisture resistance after immersion in solder is poor, and when it exceeds 90% by weight, fluidity is extremely deteriorated and moldability is poor, which is not preferable.

The epoxy resin composition of the present invention contains the above-mentioned specific epoxy resin, phenolic resin, specific polyimide resin and inorganic filler as essential components, but it is also necessary as long as it does not defeat the purpose of the present invention. Accordingly, 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 colorant such as red iron oxide, a silane coupling agent, various curing accelerators, 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, the above-mentioned specific epoxy resin, phenol resin, specific polyimide resin, inorganic filler and other components are prescribed. After blending the selected raw material components to the composition ratio of 1 and mixing them sufficiently uniformly with a mixer or the like, further performing melt mixing treatment with a hot roll or mixing treatment with a kneader, etc., then cooling and solidifying, and pulverizing to an appropriate size. Can be used as a molding material. When the molding material thus obtained is applied to sealing, coating, insulation, 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 molding material described above. 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 general method of sealing 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 this cured product is obtained. Curing by heating is 150 ° C
It is desirable to heat and cure the above.

[0021]

The epoxy resin composition of the present invention uses the above-mentioned specific epoxy resin, phenol resin, and specific polyimide resin to increase the glass transition temperature of the resin composition, resulting in thermomechanical properties and low stress. Improves the solderability and eliminates the occurrence of resin cracks after solder immersion and solder reflow.
The moisture resistance is less deteriorated.

[0022]

EXAMPLES 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 8.7% of the epoxy resin shown in Chemical formula 7 and 4.3% of the phenol resin shown in Chemical formula 11

[0024]

[Chemical 11] (However, in the formula, n represents 0 or an integer of 1 or more.) 5% of the polyimide resin shown in Chemical formula 10 above, silica powder
81%, curing accelerator 0.3%, ester wax 0.3% and silane coupling agent 0.4% are mixed at room temperature.
Molding material (A) by kneading at 90-95 ℃ and cooling and pulverizing this
Was manufactured.

Example 2 6.7% of the epoxy resin of Chemical formula 7 used in Example 1 and Chemical formula 1
2.3% of phenol resin of No. 1, 10% of polyimide resin of Chemical formula 10 used in Example 1, 80% of silica powder, 0.3% of curing accelerator
%, Ester wax 0.3%, and silane coupling agent 0.4% were mixed at room temperature, further kneaded at 90 to 95 ° C., and cooled and ground to prepare a molding material (B).

Comparative Example 1 Orthocresol Novolak type epoxy resin 17% was mixed with novolac type phenol resin 8%, silica powder 74%, curing accelerator 0.3%, ester wax 0.3% and silane coupling agent 0.4%. A molding material (C) was produced in the same manner as in Example 1.

Comparative Example 2 20% of epibis type epoxy resin (epoxy equivalent 450), 5% of novolac type phenol resin, 74% of silica powder, 0.3% of curing accelerator, 0.3% of ester wax and 0.4% of silane coupling agent were mixed. Further, the mixture was kneaded at 90 to 95 ° C. and cooled and pulverized to produce a molding material (D).

Using the molding materials A) to (D) manufactured in this way, transfer injection was performed into a mold heated to 170 ° C. and cured to seal a semiconductor chip 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 moisture resistance and solder heat resistance. The remarkable effect of the invention could be confirmed.

[0029]

[Table 1] * 1: Diameter 50 mm, thickness 3 mm by transfer molding
The molded product of No. 1 was prepared, and it was left in saturated steam at 127 ° C. and 2.5 atm for 24 hours and measured by the increased weight. * 2: Make a molded product similar to the case of water absorption rate and
After post-curing for a certain time, a test piece of an appropriate size was prepared and measured using a thermomechanical analyzer. * 3: Tested according to JIS-K-6911. * 4: Using a molding material, a silicon chip with two aluminum wirings is bonded to a normal 42 alloy frame and transfer molded at 175 ° C for 2 minutes.
Post curing was carried out at 8 ° C for 8 hours. The molded product thus obtained was previously subjected to moisture absorption treatment at 40 ° C., 95% RH for 100 hours, and then subjected to 250
It was soaked in a solder bath at ℃ for 10 seconds. After that, a humidity resistance test was conducted in saturated steam at 127 ° C and 2.5 atm to evaluate the time for 50% disconnection (defect occurrence) due to aluminum corrosion. * 5: QFP (14 x 14 x 1.4 m) with 8 x 8 mm dummy chip
m) Package and use molding compound for 2 at 175 ° C
After transfer molding for 1 minute, post-curing was performed at 175 ° C. for 8 hours. The semiconductor encapsulation device manufactured in this way is
After absorbing moisture for 85% for 24 hours, put it in a solder bath at 240 ℃ 1
Soaked for a minute. Then, the package surface was observed with a stereoscopic microscope to evaluate the presence or absence of external resin cracks.

[0030]

As is clear from the above description and Table 1, the epoxy resin composition and the semiconductor encapsulation device of the present invention have excellent moisture resistance and solder heat resistance, are less affected by moisture absorption, and are less susceptible to electrode corrosion. It is possible to remarkably reduce the occurrence of leakage current due to disconnection and moisture, and it is possible to guarantee the reliability for a long time.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C08L 63/00 NKT H01L 23/29 23/31

Claims (2)

[Claims] 1. An epoxy resin represented by the following general formula (A): (However, in the formula, R ¹ is a C _j H _{2j + 1} group, and R ² is C _k H _{2k + 1.}
R ³ represents a C ₁ H _{2l + 1} group, R ⁴ represents a C _m H _{2m + 1} group, and j, k, l, m and n in each group are 0.
Or represents an integer of 1 or more) (B) Phenolic resin, (C) Polyimide resin represented by the following general formula, and (However, in the formula, R ⁵ is a C ₁ H _{2l + 1} group, and R ⁶ is a C _m H _{2m + 1 group.}
Each represents a group, and l and m in each group represent 0 or an integer of 1 or more) (D) The inorganic filler is an essential component, and the resin composition contains 25 to 90 parts by weight of the (D) inorganic filler. % Of epoxy resin composition. 2. An epoxy resin represented by the following general formula (A): (However, in the formula, R ¹ is a C _j H _{2j + 1} group, and R ² is C _k H _{2k + 1.}
R ³ represents a C ₁ H _{2l + 1} group, R ⁴ represents a C _m H _{2m + 1} group, and j, k, l, m and n in each group are 0.
Or represents an integer of 1 or more) (B) a phenol resin, (C) a polyimide resin represented by the following general formula, and (However, in the formula, R ⁵ is a C ₁ H _{2l + 1} group, and R ⁶ is a C _m H _{2m + 1 group.}
Each represents a group, and l and m in each group represent 0 or an integer of 1 or more) (D) The inorganic filler is an essential component, and the resin composition contains 25 to 90 parts by weight of the (D) inorganic filler. A semiconductor encapsulation device, which is obtained by encapsulating a semiconductor chip with a cured product of an epoxy resin composition contained in a ratio of%.