JP3320609B2 - Epoxy resin composition for semiconductor encapsulation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a mold having good moldability,
In particular, the present invention relates to an epoxy resin composition for semiconductor encapsulation having no void in a molded product.

[0002]

2. Description of the Related Art Conventionally, electronic components such as diodes, transistors, and integrated circuits are sealed with a thermosetting resin. In particular, in an integrated circuit, an ortho-cresol novolac epoxy resin and a phenol having excellent heat resistance and moisture resistance are provided. An epoxy resin composition containing a novolak resin and an inorganic filler such as fused silica or crystalline silica as a filler is used. However, in recent years, the size of chips has increased due to the increase in the degree of integration of integrated circuits, and small and thin QFPs, SOPs, SOJs, and TSs that have been packaged on the surface of conventional DIP types have been packaged.
OP and PLCC are changing. These large packages tend to cause molding defects at the time of molding, and in particular, defects called voids tend to appear apparently after molding as compared to thin ones, and thus have a problem of poor appearance. Therefore, development of a void-free resin composition for semiconductor encapsulation suitable for encapsulating these large packages is desired.

[0003]

SUMMARY OF THE INVENTION The present invention solves these problems by including a specific silicone oil in a resin composition, thereby improving the moldability, and in particular, a resin for semiconductor encapsulation having no voids in molded articles. It is an object to provide a composition.

[0004]

The present invention comprises an epoxy resin, a phenolic resin curing agent, a curing accelerator and an inorganic filler as essential components, and comprises 83.1 to 95 of the inorganic filler in the entire epoxy resin composition. % Of a silicone oil having a structure represented by the formula (1) in the total epoxy resin composition.
It is an epoxy resin composition for semiconductor encapsulation characterized by containing about 2% by weight. Here, R ₁ is represented by (Formula 2), R ₂ is represented by (Formula 3), and R is —CH ₃ or —H. Here, M and N are 0 ≦ M ≦ 300, 0 ≦ N ≦ 300,
1 ≦ M + N

The silicone oil represented by the molecular structure of the formula (1) is a polyether-modified silicone oil having a polydimethylsiloxane structure as a main chain. The effect of lowering the surface tension characteristic of polydimethylsiloxane acts on the sealing resin composition, and the defoaming effect is exhibited, which is effective in reducing voids. In the formula (1), the polyether-modified group is a hydrophilic group, and has a structure of a polymer surfactant in combination with an alkyl group of a hydrophobic group. Therefore, it shows good compatibility with the epoxy resin. If the surfactant is well compatible with the epoxy resin, uniformity inside the resin composition,
Dispersibility is improved, which is effective in reducing voids. Furthermore, it is necessary to satisfy the relationship of 10 ≦ X / Y ≦ 30 in order to reduce voids. When X / Y is less than 10, the ratio of the polyether-modified group is increased, so that the hydrophilicity is enhanced, and water absorption that is fatal to solder crack resistance is brought about. When X / Y exceeds 30, the viscosity of the silicone oil itself increases, and the viscosity of the encapsulating resin composition using the same increases, which causes a problem in moldability. N and M are not particularly limited, but those not exceeding 300 are desirable. If it exceeds 300, the viscosity of the silicone oil itself increases, which causes a problem in the moldability of the sealing resin composition.

By adjusting the amount of the silicone oil used, voids can be reduced with little effect on other characteristics. In order to achieve the maximum void reduction effect, the content of the silicone oil represented by the formula (1) is preferably set to 0.01 to 2% by weight in the entire epoxy resin composition. If it exceeds 2% by weight, the moldability is adversely affected, and if it is less than 0.01% by weight, no effect is seen.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin used in the present invention is:
Monomers, oligomers, and polymers having an epoxy group are generally referred to, for example, biphenyl type epoxy compounds, bisphenol type epoxy compounds, phenol novolak type epoxy resins, cresol novolak type epoxy resins,
Examples thereof include a triphenolmethane-type epoxy compound, an alkyl-modified triphenolmethane-type epoxy resin, and a triazine nucleus-containing epoxy resin, which are used alone or in combination.

Examples of the phenol resin curing agent used in the present invention include phenol novolak resin, cresol novolak resin, dicyclopentadiene-modified phenol resin, phenol aralkyl resin, terpene-modified phenol resin, and triphenolmethane compound. Preferred are resins, dicyclopentadiene-modified phenolic resins, phenol aralkyl resins, terpene-modified phenolic resins, and mixtures thereof. or,
It is desirable to mix these curing agents so that the number of epoxy groups of the epoxy resin and the number of hydroxyl groups of the curing agent match.

The curing accelerator used in the present invention may be any as long as it promotes a curing reaction between an epoxy group and a hydroxyl group.
What is generally used for a sealing material can be widely used. For example, triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tris-2,6-dimethoxyphenylphosphine, 2-methylimidazole and the like are used, and these are used alone or in combination.

As the inorganic filler used in the present invention, those generally used as sealing materials can be widely used. For example, silica, alumina, silicon nitride, and aluminum nitride may be mentioned. In particular, spherical silica powder and a mixture of fused silica powder and spherical silica powder are desirable. The amount of the inorganic filler is preferably 83.1 to 95% by weight in the whole resin composition from the viewpoint of solder crack resistance. If it is less than 83.1 % by weight, the solder crack resistance is disadvantageous. If it exceeds 95% by weight, the fluidity is insufficient.

The epoxy resin composition of the present invention contains an epoxy resin, a phenolic resin curing agent, a curing accelerator, an inorganic filler and a silicone oil as essential components. Various additives such as a flame retardant such as a functionalized epoxy resin, antimony trioxide, and hexabromobenzene, and a low stress additive such as a rubber may be appropriately compounded. In order to produce the encapsulating epoxy resin composition of the present invention as a molding material, epoxy resin,
After sufficiently uniformly mixing the phenolic resin curing agent, curing accelerator, inorganic filler, silicone oil and other additives with a mixer or the like, further heat roll or kneader,
It can be kneaded with a twin-screw kneader, cooled and pulverized to obtain a molding material for sealing.

[0012]

EXAMPLES The present invention will be specifically described with reference to Examples. << Example 1 >> The following composition-Biphenyl type epoxy resin (E-1) 7.6 parts by weight-Phenol novolak resin (P-1) 5.4 parts by weight-Spherical silica powder (average particle size 15 m) 85.0 Parts by weight-carbon black 0.3 parts by weight-silane coupling agent 1.4 parts by weight-carnauba wax 0.5 parts by weight-triphenylphosphine 0.2 parts by weight-silicone oil represented by the formula (1) (11) 1.0 part by weight was mixed at room temperature with a mixer, kneaded with a roll at 70 to 110 ° C., cooled and pulverized to obtain a molding material. This was evaluated by the following evaluation methods, and the results are shown in Table 1. still,
Silicone oil (11) means X / Y = 11 in (Equation 1)
And the same applies hereinafter .

Examples 2 to 7 Molding materials were obtained in the same manner as in Example 1 with the formulations shown in Table 1, and evaluated in the same manner. << Comparative Examples 1 to 14 >> Molding materials were obtained in the same manner as in Example 1 with the formulations shown in Table 2, and evaluated in the same manner.

<< Evaluation Method >> Spiral flow: A flow when molding is performed at 175 ° C. under a pressure of 70 kgf / cm ² for 120 seconds using a mold conforming to EMMI-I-66. Moldability: by 16pDIP low pressure transfer molding. Molding is performed at a molding temperature of 180 ° C., a pressure of 100 kgf / cm ² , an injection time of 15 seconds, a curing time of 60 seconds (excluding the injection time), and a preheating temperature of 80 ° C., and the releasability of the cull and the runner portion is visually determined. Bacol hardness: The hardness of the runner part 10 seconds after the mold opening in the 16pDIP low-pressure transfer molding is measured with a Bacol hardness meter (# 935). Water absorption: After post-curing a 50φ disk (3mm thick)
The treatment was performed at 85 ° C./85% for 168 hours in a thermo-hygrostat, and the weight change rate (%) before and after the treatment was determined. Solder crack resistance evaluation: 52pQFP (14 × 14 ×
(2 mm thick), and after post-curing, it is treated in a thermo-hygrostat at 85 ° C./85% for 172 hours. Immediately after processing, IR
After the treatment at 240 ° C. for 10 seconds in a reflow furnace, after the reflow treatment, external cracks are visually observed to evaluate how many of the eight packages have cracks. Solder PCT: 52pQFP (14x14x2mm thickness)
After post-curing, 85 ° C / 8 in a thermo-hygrostat
Treat at 5% for 168 hours. Immediately after the treatment, a treatment at 240 ° C. for 10 seconds is performed by an IR reflow furnace, and after the reflow treatment, a PCT treatment (125 ° C., 2.4 atm saturation) is performed. For measurement, remove the package from the pot in a certain time,
A dedicated tester that does not cause conduction failure is returned to the shuttle again, and continues until 500 hours. Void: 160pQFP (28 × 28 × 3.7mm
t) a molding temperature of 180 ° C., an injection time of 15 seconds, and a curing time of 6
Molding was performed for 0 seconds (excluding the injection time) and at a preheating temperature of 80 ° C. NO molding conditions. The number of internal voids in the molded product was confirmed by an ultrasonic flaw detector. The total number of internal voids in the four packages is defined as the number of voids.

The silicone oil used in Comparative Examples 12 to 14 is FZ-3730 [manufactured by Nippon Unicar Co., Ltd., containing an epoxy group and a polyoxyalkylene having a terminal methyl in the side chain]. The structural formulas of the epoxy resin (E-1) and phenol novolak resin (P-1) used for the following are shown below.

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Table 1 Example 1 2 3 4 5 6 7 Blended (parts by weight) E-1 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.6 P-1 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 Spherical silica powder 83.6 84.1 83.1 83.6 83.6 84.1 83.1 Carbon black 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Silane coupling agent 1.4 1.4 1.4 1.4 1.4 1.4 1.4 Carnauba wax 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Triphenylphosphine 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Silicone oil (11) 1.0 0.5 1.5 Silicone oil (22) 1.0 Silicone oil (28) 1.0 0.5 1.5 Characteristics Spiral flow 121 109 134 107 99 87 102 Formability ○ ○ ○ ○ ○ ○ ○ Bacol hardness 87 88 86 86 86 88 85 Water absorption 0.27 0.27 0.28 0.26 0.25 0.24 0.25 Solder crack 0 0 0 0 0 0 0 solder PCT 100hr 0 0 0 0 0 0 0 200hr 0 0 0 0 0 0 0 300hr 0 0 0 0 0 0 0 500hr 2 1 1 1 0 0 1 void 0 1 0 0 0 0

Table 2 Comparative Example 1 2 3 4 5 6 7 Blended (parts by weight) E-1 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.6 P-1 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 Spherical silica powder 83.6 82.1 84.6 82.1 84.6 82.1 84.6 Carbon black 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Silane coupling agent 1.4 1.4 1.4 1.4 1.4 1.4 1.4 Carnauba wax 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Triphenylphosphine 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Silicone oil (9) 1.0 2.5 Silicone oil (11) .005 2.5 Silicone Oil (22) .005 2.5 Silicone oil (28) .005 Characteristics Spiral flow 135 141 95 139 89 122 80 Moldability ○ × ○ × ○ × ○ Bacoal hardness 85 77 87 75 88 77 86 Water absorption 0.29 0.31 0.27 0.30 0.27 0.30 0.26 solder cracking 1 2 0 2 0 2 0 solder PCT 100hr 0 4 0 0 0 0 0 200hr 1 7 0 0 0 0 0 300hr 4 8 0 0 0 0 0 500hr 8 over 0 1 0 1 0 Bo De 2 0 22 0 38 0 26

Table 3 Comparative Example 8 9 10 11 12 13 14 blending (parts by weight) E-1 7.6 7.6 7.6 7.6 7.6 7.6 7.6 P-1 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 Spherical silica powder 82.1 83.6 82.1 84.6 Carbon black 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Silane coupling agent 1.4 1.4 1.4 1.4 1.4 1.4 1.4 Carnauba wax 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Triphenylphosphine 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Silicone oil (28) 2.5 Silicone oil (31) 1.0 2.5 Silicone oil 1.0 1.5 0.5 Spiral flow 115 61 53 91 101 111 97 Formability × ○ × ○ ○ ○ ○ Bacoal hardness 72 81 66 88 80 79 81 Water absorption 0.29 0.28 0.30 0.26 0.29 0.30 0.27 Solder crack 1 6 2 0 2 3 1 Solder PCT 100 hr 10 200 000 200 hr 3140 000 300 hr 7 280 000 500 hr 87-0 1 210 Void 0 0 0 58 8 5 11

[0019]

According to the present invention, it is possible to eliminate voids in a molded package.

──────────────────────────────────────────────────続 き Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI (C08L 63/00 H01L 23/30 R 83:10) (56) References JP-A-1-272622 (JP, A) JP JP-A-4-363316 (JP, A) JP-A-4-85358 (JP, A) JP-A-2-166116 (JP, A) JP-A-2-129220 (JP, A) JP-A-4-224819 (JP) JP-A-5-105861 (JP, A) JP-A-5-210883 (JP, A) JP-A-6-216281 (JP, A) JP-A-7-300517 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 63/00-63/10 C08L 83/10 C08G 59/62 H01L 23/29

Claims (1)

(57) [Claims] An epoxy resin, a phenol resin curing agent,
An epoxy resin composition comprising a curing accelerator and an inorganic filler as essential components, a silicone oil containing 83.1 to 95% by weight of the inorganic filler in the entire epoxy resin composition, and having a structure of the following (formula 1) Containing 0.01 to 2% by weight, and 1
An epoxy resin composition for semiconductor encapsulation, wherein 0 ≦ X / Y ≦ 30 is satisfied. Here, R ₁ is represented by (Formula 2), R ₂ is represented by (Formula 3), and R is —CH ₃ or —H. Here, M and N are 0 ≦ M ≦ 300, 0 ≦ N ≦ 300,
1 ≦ M + N