JPS6320447B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an epoxy resin composition for semiconductor encapsulation that has excellent compatibility, excellent moisture resistance after curing, and low internal stress. [Prior art] Currently, resin encapsulation methods are widely used to encapsulate semiconductor elements such as ICs and LSIs using silicone resin or epoxy resin. Of these, epoxy resin has relatively excellent airtightness. Since it is also inexpensive, it is widely used as a resin for semiconductor encapsulation. However, there remain unresolved problems with conventional epoxy resin compositions for semiconductor encapsulation. 1st
Furthermore, internal stress caused by hardening of the resin causes deformation, misalignment, and disconnection of semiconductor element wiring and bonding wires. Second, efforts to reduce this internal stress, such as blending flexible resins, blending fibrous substances, and increasing the amount of inorganic fillers, lower the glass transition point, reduce moisture resistance, and deform wiring. or lead to disconnection. Although this method has been studied in Japanese Patent Laid-Open No. 55-3412, etc., it has not yet been possible to obtain a resin suitable for use as a sealing resin for ICs and LSIs, which are becoming increasingly larger and more highly integrated in recent years. For example, silicon compounds that can reduce internal stress are incompatible with epoxy resins, so secondary amines that are compatible with epoxy resins and silicon compounds are simply added to epoxy resins and silicon compounds. The resin composition obtained also undergoes phase separation. [Summary of the invention] This invention was made in order to eliminate the drawbacks of the above-mentioned conventional products.
This curing agent (b) and the reaction product of the silicon compound shown below and the secondary amine shown below 50
The silicon compound has the general formula (In the formula, R ₁ contains an epoxy group, R is a phenyl group, a vinyl group, or an alkyl group having 1 to 3 carbon atoms, R ₂ is hydrogen, and x and y are positive integers, and the molecular weight is as shown below. The molecular weight is in the range of 300 to 12,000. The secondary amine is at least one of imidazole compounds, piperazine, piperidine and morpholine. Another invention of this invention is epoxy resin 100
Part by weight (a), its curing agent (b), and 50 parts by weight or less (c) of a reaction product of the silicon compound shown below and the secondary amine shown below,
Silicon compounds have the general formula (In the formula, R ₁ includes an epoxy group, R is a phenyl group, a vinyl group, or an alkyl group having 1 to 3 carbon atoms, and z is a positive integer that sets the molecular weight as described below.) Molecular weight indicated by 300-6500
It is within the range of . The secondary amine is at least one of imidazole compounds, piperazine, piperidine and morpholine. By using the above, an epoxy resin composition for semiconductor encapsulation that has excellent compatibility, has excellent moisture resistance without deterioration of resin physical properties such as a decrease in glass transition point after curing, and has low internal stress. The purpose is to provide [Embodiments of the Invention] Epoxy resins used in an embodiment of the present invention include various types such as novolak epoxy resins, bisphenol A epoxy resins, and alicyclic epoxy resins. The resins can be used alone or in combination of two or more. In addition to these epoxy resins, a brominated bisphenol A-based epoxy resin can also be used if necessary. Among them, it is preferable to use a novolac type epoxy resin which has excellent high-temperature properties. As the curing agent for the epoxy resin used in one embodiment of the present invention, for example, commonly known amines, acid anhydrides, and phenols can be used. As a stopper, it is preferable to use, for example, acid anhydrides and phenols. Examples of acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride,
Methylhexahydrophthalic anhydride, maleic anhydride, hexachloroendomethylenetetrahydrophthalic anhydride, and the like can be used. but,
It is preferable to use hexahydrophthalic anhydride and tetrahydrophthalic anhydride, which have excellent high temperature properties and normal pressure injection properties. These acid anhydrides can be used alone or in combination of two or more, and the amount used is usually in the range of 0.4 to 1.2 equivalents, preferably 0.6 to 1.0 equivalents, per equivalent of the epoxy resin. If the amount is less than 0.4 equivalent, it will not be cured sufficiently and its mechanical properties will be poor, resulting in a decrease in heat distortion temperature and moisture resistance. Moreover, when the amount exceeds 1.2 equivalents, the excess acid anhydride reduces moisture resistance. Phenols include bisphenol A, trimethylolallyloxyphenol, phenol novolac resins with a low degree of polymerization, epoxidized and butylated phenolic resins, and "Supper".
Beekacite”1001 (Japan Reichhold Chemical Industry Co., Ltd.
(manufactured by Hitachi, Ltd.), "Hitanol" 4010 (manufactured by Hitachi, Ltd.),
Scado form2.9 (manufactured by Scado Zwoll in the Netherlands),
There are phenolic resins known under trade names such as Methylor 75108 (manufactured by General Electric Company, USA). The amount used is the same as for acid anhydrides. Although phenolic curing systems are superior to acid anhydride curing systems in terms of moisture resistance, they cause an increase in the viscosity of the resin composition. In order to obtain high moisture resistance, low internal stress, and high workability, it is also possible to use a composite curing system with acid anhydrides. The silicon compound used in one embodiment of this invention has the general formula (In the formula, R ₁ contains an epoxy group, R is a phenyl group, a vinyl group, or an alkyl group having 1 to 3 carbon atoms, R ₂ is hydrogen, and x and y are positive integers, and the molecular weight is as shown below. For example, silicone oil or silicone rubber has a molecular weight in the range of 300 to 12,000. Further, as a silicon compound used in an embodiment of another invention of this invention, the general formula (In the formula, R ₁ contains an epoxy group, R is a phenyl group, a vinyl group, or an alkyl group having 1 to 3 carbon atoms, R ₂ is hydrogen, and z is a positive integer, and the molecular weight is set as shown below. For example, silicone oil or silicone rubber has a molecular weight in the range of 300 to 6,500. As the secondary amine used in one embodiment of the present invention, imidazole compounds such as 2-ethyl-4-methylimidazole, 2-methyl-imidazole, benzimidazole and N-alkyl-imidazole are preferred, and N-methylpiperazine , hydroxyethylpiperazine, piperidine and morpholine. Note that the silicon compound according to the present invention is
By pre-reacting with a secondary amine, which is a curing accelerator, it is possible to uniformly and stably disperse the silicone compound in the epoxy resin, and this reaction can be easily carried out at relatively low temperatures from room temperature to 100°C. The reaction can be controlled with toluene or other organic solvents. In addition, the amount of secondary amine and silicon compound used is
Epoxy group of silicon compound 0.6 to 1 mol
1.5 mol is preferable, and 0.8 to 1.2 is more preferable. If the epoxy group is 0.6 mol or less, the moisture resistance after curing will decrease, and if the epoxy group is 1.5 mol or more, the dispersibility will decrease. Furthermore, the above-mentioned secondary amine is the above-mentioned epoxy resin.
It is preferably 10% by weight or less based on 100 parts by weight. Ten
If the amount exceeds % by weight, moisture resistance decreases. Next, the reaction product of the silicon compound and secondary amine obtained as described above is preferably 50 parts by weight or less, especially 3 to 30 parts by weight, based on 100 parts by weight of the epoxy resin.
Weight percent is preferred. If it exceeds 50% by weight, the mechanical strength after curing will decrease. The composition of the present invention may optionally contain inorganic fillers such as crystalline silica, fused silica, alumina, and antimony trioxide, colorants such as carbon black, carnauba wax, polyethylene wax, etc. Mold release agents and flame retardants may also be included. The composition of the present invention can be easily prepared by using a known mixing device, such as a roll, kneader, or mixer, which is used in the preparation of conventional epoxy resins and silicone resins. This invention will be explained below with reference to Examples and Comparative Examples. In Examples 1 to 9 and Comparative Examples 3 to 10, a curing accelerator and a silicon compound (Table 1 below) were stirred and reacted at 60°C. Examples 1 to 9 and Comparative Example 1
~10 is a mixture of an epoxy resin, a curing agent, a curing accelerator, a silicone compound, an inorganic filler, a coloring agent, and a mold release agent in the proportions shown in Table 2 (later) and Table 3 (later), and using a kneader. The mixture was mixed under vacuum for 10 minutes at a temperature of 40°C to obtain an epoxy resin composition. The stability, crack resistance and moisture resistance after curing at 180° C. for 16 hours of the composition obtained as described above were investigated, and the results are shown in Tables 4 and 5. That is, the stability was evaluated by standing at 40° C. and visually observing the presence or absence of phase separation. Crack resistance was evaluated based on the temperature at which cracks occur when the orifice washer is embedded. For evaluation of moisture resistance and low stress, the semiconductor element for moisture resistance evaluation was vacuum cast molded, and the temperature was 121℃, 2 atmospheres, and relative humidity 100℃.
A PCT (Pressure Cooker Test) was conducted under the conditions of % to investigate the failure occurrence time. A similar test was also conducted after immersion in a 260°C solder bath. The results are shown in Table 4 (described later) and Table 5 (described later). According to this, all the resin compositions of one example of the present invention are stable. Furthermore, the failure occurrence time of the semiconductor element for moisture resistance evaluation of the resin composition of one example of the present invention is similarly slow both when not immersed in solder and after immersed in a 260° C. solder bath, and the difference between them is small. On the other hand, the failure occurrence time of the semiconductor element for moisture resistance evaluation of the resin composition of the comparative example is fast even without immersion in solder, and the time becomes even faster after immersion in a 260°C solder bath, and the difference is also small. growing. From this, it can be seen that the resin composition of one example of the present invention has excellent moisture resistance and low internal stress. Furthermore, it can be seen that the crack generation temperature of the resin composition of one example of the present invention is low, and the resin composition has excellent crack resistance. Note that some of the resin compositions of comparative examples had excellent crack resistance, but in those cases, the other physical properties mentioned above were inferior. In addition, the glass transition point of Example 6 was 153°C.
No decrease in the glass transition point was observed due to the addition of silicon compounds, and there were no problems compared to conventional products.

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〔Effect of the invention〕

As explained above, this invention is based on epoxy resin.
100 parts by weight (a), its curing agent (b), and 50 parts by weight or less (c) of a reaction product of the silicon compound shown below and the secondary amine shown below. is a general formula (In the formula, R ₁ contains an epoxy group, R is a phenyl group, a vinyl group, or an alkyl group having 1 to 3 carbon atoms, R ₂ is hydrogen, and x and y are positive integers, and the molecular weight is as shown below. The molecular weight is in the range of 300 to 12,000. The secondary amine is at least one of imidazole compounds, piperazine, piperidine and morpholine. In addition, another invention of this invention is epoxy resin 100
Part by weight (a), its curing agent (b), and 50 parts by weight or less (c) of a reaction product of the silicon compound shown below and the secondary amine shown below,
Silicon compounds have the general formula (In the formula, R ₁ includes an epoxy group, R is a phenyl group, a vinyl group, or an alkyl group having 1 to 3 carbon atoms, and z is a positive integer that sets the molecular weight as described below.) Molecular weight indicated by 300-6500
It is within the range of . The secondary amine is at least one of imidazole compounds, piperazine, piperidine and morpholine. By using the above, an epoxy resin composition for semiconductor encapsulation that has excellent compatibility, has excellent moisture resistance, and has low internal stress without deterioration of resin physical properties such as a decrease in glass transition point after curing. It is extremely useful as a sealing resin for LSI and VLSI, for example.

Claims (1)

[Claims] 1. 100 parts by weight of epoxy resin (a), a curing agent for this (b),
and an epoxy resin composition for semiconductor encapsulation containing 50 parts by weight or less (c) of a reactant of a silicon compound shown below and a secondary amine shown below. Silicon compounds have the general formula (In the formula, R ₁ contains an epoxy group, R is a phenyl group, a vinyl group, or an alkyl group having 1 to 3 carbon atoms, R ₂ is hydrogen, and x and y are positive integers, and the molecular weight is as shown below. The molecular weight is in the range of 300 to 12,000. The secondary amine is at least one of imidazole compounds, piperazine, piperidine and morpholine. 2 100 parts by weight of epoxy resin (a), its curing agent (b),
and an epoxy resin composition for semiconductor encapsulation containing 50 parts by weight or less (c) of a reactant of a silicon compound shown below and a secondary amine shown below. Silicon compounds have the general formula (In the formula, R ₁ includes an epoxy group, R is a phenyl group, a vinyl group, or an alkyl group having 1 to 3 carbon atoms, and z is a positive integer that sets the molecular weight as described below.) Molecular weight indicated by 300-6500
It is within the range of . The secondary amine is at least one of imidazole compounds, piperazine, piperidine and morpholine.