JPH0575776B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an epoxy resin composition for semiconductor encapsulation that has excellent thermal shock resistance, and more specifically relates to an epoxy resin composition for semiconductor encapsulation that has excellent crack resistance even when subjected to rapid temperature changes. The present invention relates to a stopper epoxy resin composition. [Prior Art] In response to the recent trend toward lighter, thinner, and smaller electronic products, semiconductor assembly manufacturers are shifting from conventional through-hole mounting to surface mounting in order to improve the packaging density of semiconductor devices. On automated surface mounting lines, semiconductor packages are subject to rapid temperature changes when soldering leads, which can cause cracks in the resin molding, deteriorate the interface between lead resins, and reduce moisture resistance as a result. Problems such as doing this may occur. To solve these problems, thermoplastic oligomers are added (Japanese Patent Laid-Open No. 62-115849) and various silicone compounds are added (Japanese Patent Laid-Open No. 62-115850) to alleviate the thermal shock during solder immersion. , 62−
116654, 62-128162) and silicone modification (Japanese Unexamined Patent Publication No. 116654, 62-128162), but all of these techniques cause cracks in the molded part after being dipped in solder, resulting in poor reliability. However, it has not been possible to obtain an excellent resin-sealed semiconductor device.
In particular, the addition of these additives poses the problem of deteriorating workability during molding, and methods have been considered to improve the special production by changing the structure of the resin itself. These methods of changing the structure of the resin itself have various drawbacks, such as complicating the reaction process, and so far no satisfactory product has been obtained. [Problems to be Solved by the Invention] The present invention solves these problems by using phenolic resins represented by the chemical structural formulas of formulas () to () as a phenolic resin curing agent.

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[Means to solve the problem]

The epoxy resin composition of the present invention has extremely superior thermal shock resistance compared to conventional sealing resin compositions.

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[C] (In the formula, k, l, and m represent integers from 0 to 10.) The phenolic resins represented by the above formulas () to () have flexibility and water resistance in the main chain of the molecule, respectively. A flexible curing agent containing bicycloheptane, cyclopentane, and cyclohexane. By using this flexible curing agent, an epoxy resin composition with extremely excellent thermal shock resistance that could not be obtained by conventional methods. can be obtained. Thermal shock resistance can be maximized by adjusting the amount of the phenol resin and mixture thereof used. In order to achieve the effect of thermal shock resistance, at least one type or a mixture of one or more types selected from the phenolic resins represented by formulas () to () should be used in an amount of 30% by weight or more, more preferably 50% by weight of the total phenolic resin. It is desirable to use % or more. In this case, if it is less than 30% by weight, flexibility and water resistance will not improve and thermal shock resistance will be insufficient. Furthermore, the ratio of the mixture of the three types of phenolic resins represented by formulas () to () is preferably equimolar in view of the balance of curability and thermal shock resistance of the epoxy resin composition. Further, the values of k, l, and m in the formula must be in the range of 0 to 10. The values of k, l, m are
When it is larger than 10, fluidity decreases and moldability deteriorates. Other phenolic resin curing agents used here refer to polymers in general that cure and react with epoxy resins, such as phenol novolac resins,
Common names include cresol novolak resin, dicyclopentadiene-modified phenolic resin, and paraxylene-modified phenolic resin acid anhydride. The epoxy resin used in the present invention refers to any resin having an epoxy group. For example, bisphenol type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin,
Refers to epoxy resins containing triazine nuclei, etc.
These may be used alone or in combination. Inorganic fillers used in the present invention include ordinary silica powder such as fused silica, crystalline silica, porous silica, and secondary agglomerated silica, as well as fillers in general such as alumina, calcium carbonate, and carbon fiber. Preference is given to using silica, porous silica, and secondary agglomerated silica. The curing accelerator used in the present invention may be one that promotes the reaction between an epoxy group and a phenolic hydroxyl group, and a wide range of materials commonly used in sealing materials can be used, such as diaza. Bicycloundecene (DBU), triphenylphosphine (TPP), dimethylbenzylamine (BDMA)
and 2-methylimidazole (2MZ) are used alone or in combination of two or more. The epoxy resin composition for sealing of the present invention contains an epoxy resin, a curing agent, an inorganic filler, and a curing accelerator as essential components, but in addition to these, if necessary, a silane coupling agent, a brominated epoxy resin, and a trioxide Various additives such as flame retardants such as antimony and hexabromobenzene, colorants such as carbon black and red iron, mold release agents such as natural wax and synthetic wax, and low stress additives such as silicone oil and rubber are appropriately blended. There is no problem. In addition, in order to produce the epoxy resin composition for sealing of the present invention as a molding material, the epoxy resin, curing agent, curing accelerator, filler, and other additives are sufficiently and uniformly mixed using a mixer or the like. After that, the mixture is further melt-kneaded using a heated roll or a kneader, cooled, and then pulverized to obtain a molding material. These molding materials can be applied to sealing, covering, insulating, etc. electronic or electrical components. [Example] Example 1 The following composition Phenol resin represented by formulas () to ()

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[Chemical formula] However, the phenolic resins of formulas () to () are in equimolar amounts, and k, l, and m in the formula each have a value of 0, 1, or 2, and the ratio is 2:
5:3 mixture. 6 parts by weight phenol novolak resin 4 parts by weight orthocresol novolak epoxy resin
20 parts by weight Fused silica powder 68.8 parts by weight Torphenylphosphine 0.2 parts by weight Carbon black 0.5 parts by weight Carnauba wax 0.5 parts by weight were mixed in a mixer at room temperature, kneaded at 70 to 100°C with a twin-screw roll, and after cooling. It was crushed and used as a molding material. The obtained molding material was made into a tablet, and a 6 x 6 mm chip was sealed in a 52p package for a solder crack test using a low-pressure transfer molding machine at 175°C, 70 kg/cm ² and 120 seconds, and solder moisture resistant. A 3 x 6 mm chip was sealed in a 16 pSOP package for performance testing. The following solder crack test and solder moisture resistance test were conducted on the sealed test device. Solder crack test: 85 times the sealed test element
It was processed for 48 hours and 75 hours in an ambient environment of 85% RH at ℃, and then immersed in a solder bath at 240℃ for 10 seconds, and external cracks were observed with a microscope. Solder moisture resistance test: sealed test element at 85℃
Then, it was treated for 75 hours in an environment of 85% RH, and then
After being immersed in a solder bath at 240°C for 10 seconds, a pressure vacuum test (125°C, 100% RH) was performed to measure open defects in the circuit. Examples 2 and 3 A molding material was obtained in the same manner as in Example 1 by blending according to the recipe in Table 1. A sealed molded article for testing was obtained using this molding material, and a solder crack test and a solder moisture resistance test were conducted in the same manner as in Example 1 using this molded article. The test results are shown in Table 1. Comparative Examples 1 and 2 A molding material was obtained in the same manner as in Example 1 by blending according to the recipe in Table 1. A sealed molded article for testing was obtained using this molding material, and a solder crack test and a solder moisture resistance test were conducted in the same manner as in Example 1 using this molded article. The test results are shown in Table 1.

〔Effect of the invention〕

According to the present invention, it is possible to obtain an epoxy resin composition that has heat resistance, water resistance, and flexibility that could not be obtained using conventional techniques. Because of its excellent crack resistance and good moisture resistance, it is used for sealing electronic and electrical components, coating insulation, etc., especially in highly integrated large chip ICs mounted on surface mount packages. Suitable for products where reliability is very important.

Claims (1)

[Claims] 1 (A) Epoxy resin (B) At least one phenolic resin selected from the phenolic resins represented by the chemical structural formulas () to () in an amount of 30% of the total phenolic resin. ~100% by weight phenolic resin curing agent. [C] [C] [C] (In the formula, k, l, and m represent integers from 0 to 10.) (C) Inorganic heavy filler (D) A curing accelerator is an essential component. An epoxy resin composition for semiconductor encapsulation.