KR910002426B1 - Polyimide resin compositions for ancapsulating semiconductor elements - Google Patents

Abstract

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Description

Polyimide Resin Composition for Semiconductor Device Sealing

The present invention relates to a polyimide resin composition for semiconductor element sealing, and more particularly, to a polyimide resin composition for semiconductor element sealing excellent in fluidity, moldability and thermal stress resistance and moisture resistance.

As a general method for manufacturing a resin encapsulated semiconductor, a method of sealing a semiconductor element with a resin for direct semiconductor encapsulation has been used. The materials used include thermosetting resins such as epoxy, silicon, phenol, and phthalate compounds. have.

The sealing material for semiconductor devices should have good heat resistance, moisture resistance and mechanical strength, and should have a moderate hardness that does not wear molds, and a small difference in thermal expansion coefficient from that for internal sealing during cooling cycle tests, and prevents heat generation of semiconductor devices. In order to do so, it is preferable to have good thermal conductivity.

The conventional resin satisfies general physical properties, but the thermal stress distortion phenomenon is remarkably generated due to the difference in thermal expansion coefficient between the sealing resin and the inner sealing material, there is a problem in that the heat resistance of the resin itself has a limit.

In recent years, as semiconductor devices have been highly integrated, various functional units of the devices have been miniaturized, and device pellets themselves have been rapidly enlarged. Thus, satisfactory results cannot be obtained with conventional sealing resins. For example, the epoxy resin composition cured with a phenol noble epoxy resin used as a semiconductor element sealing resin has been excellent in water absorption, electrical properties and moldability at high temperatures, and thus has been the mainstream of mold resins. When sealing a large element pellet having a fine surface structure using a resin composition, the aluminum (Al) pattern on the surface of the element pellet is caused by thermal stress distortion caused by the difference in thermal expansion coefficient between the inner seal and the sealing resin. Phosphoric acid glass (PSG) film, a silicon nitride (Sin) film, or element pellets, which is a coating material for protecting the film, may occur, and a resin molded product may be separated after the binding wire is disconnected or sealed. In particular, when the cold cycle test is performed, this phenomenon occurs more frequently, and when the pellets are opened, the device characteristics are not good and the protective film is opened, so that the aluminum pattern is corroded.

For this reason, it is necessary to reduce the stress on the sealing material of the sealing resin and to increase the adhesion between the sealing resin and the PSG film or the SiN film glass film of the device. Furthermore, the hardened material is the aluminum pattern formed on the surface of the device. In order to prevent the corrosion as much as possible, it is necessary to lower the concentration of halogen compounds such as chlorine and to maintain the high level of electrical insulation at the time of hygroscopic or high temperature.

On the other hand, in order to reduce the stress on the seal as described above, it is preferable to synthesize a resin having a low elastic modulus and an expansion coefficient, and to prevent the thermal shock resistance or the breaking of the binding wire, it is necessary to make the glass transition point above a certain temperature. . In the case of the epoxy resin which is the mainstream of the conventional sealing resin, the addition of a plasticizing agent in order to have a low elasticity can obtain the effect of low elasticity, but the binding wire open resistance is deteriorated due to the rapid decrease in mechanical properties or glass transition temperature. When the inorganic filler is weighed for low expansion, the coefficient of thermal expansion decreases, but the moldability deteriorates due to the increase in the elastic modulus and the viscosity.

As described above, as a conventional material, a sealing resin having a low elastic modulus and a low thermal expansion coefficient at a high glass transition temperature could not be obtained.

Accordingly, the present inventors satisfy the requirements of the above-mentioned semiconductor sealing resin, and the cured product maintains a high glass transition temperature and has excellent thermal stress resistance, and has excellent moisture resistance and thermal shock resistance than epoxy resins for sealing semiconductor devices. As a result of adding silica powder and silicone oil to the modified bismaleimide resin, which is a novel material for preparing a polyimide resin composition, it has been found that the above disadvantages can be eliminated at once, thereby completing the present invention.

That is, the present invention 1) 20-50 parts by weight of modified bismaleimide resin in which aromatic primary diamine and aromatic secondary diamine are added to bismaleimide having a molecular weight of 600-1600 and a softening point of 40-110 ° C., and 2) silica powder. 50-80 parts by weight, 3) a composition comprising a silicone oil 0.8-25 parts by weight.

The modified bismaleimide resin of component 1) used in the present invention is a component used only in the present invention, and Michael addition reaction of bismaleimide with aromatic primary diamine and aromatic secondary diamine ( The resin obtained by Michael addition reaction) has a molecular weight of 600-1600, a softening point of 40-110 占 폚, preferably a molecular weight of 800-1000, and a softening point of 50-70 占 폚.

Its amount is preferably 20 to 50 parts by weight with respect to the precursor composition.

If the softening point is 40 ℃ or less, the generation of fresh during the molding is significantly increased, if the temperature is 110 ℃ or more it is difficult to seal due to the deterioration of fluidity.

Bismaleimide used for the synthesis | combination of the modified bismaleimide resin which is l) component in the composition of this invention is a substance represented with the following general formula (I).

Wherein Ar is an aromatic group.

Examples of the compound of the general formula (I) include N, N'-1,3-phenylene bismaleimide, N, N'-4,4'-diphenylmethane bismaleimide, N, N'-4 , 4'-diphenylether bismaleimide, N, N'-4,4'-diphenylsulfone bismaleimide, N, N'-3,4-diphenylsulfone bismaleimide, N, N'-4 , 4'-dicyclohexyl methane bismaleimide, N, N'-4,4'-dimethylene cyclohexane bismaleimide, N, N'-4,4'-diphenyl cyclohexane bismaleimide, N, N'-1, 3- xylide bismaleide, 2, 4-bismaleimide toluene, 2, 6-bis maleimide toluene, etc. are mentioned.

In addition, the aromatic secondary diamine used for the synthesis | combination of modified bismaleimide of this invention is a substance represented with the following general formula (II).

Wherein Ar 'is an aromatic group and R is an aliphatic group. Examples of the compound of formula (II) include N, N'-dimethyl-4,4'-diamino diphenylmethane, N, N'-methylethyl-4,4'-diamino diphenylmethane, N, N '-Diethyl-4,4'-diamino diphenylmethane, N, N'-dimethyl-4,4'-diamino diphenylsulfone, N, N'-diphenyl-4,4'-diamino di Phenylether, N- (1,3-dimethylbutyl) -N'-phenyl-paraphenylenediamine, N-isopropyl-N'-phenyl-paraphenylenediamine, N, N'-diphenyl-paraphenylene Diamine, N, N'-dimethyl-2,4-diazino toluene, N, N'-dimethyl-2,6-diaminotoluene, N, N'-dicyclohexyl-4,4'-diamino diphenyl Methane etc. are mentioned.

Aromatic primary diamines use methylene dianiline.

In the synthesis of the modified bismaleimide, the molar ratio of bismaleimide and diamine is used at 1.2: 1 -4.0: 1, preferably 2: 1: 1: 1. In addition, the molar ratio of primary diamine and secondary diamine in the aromatic diamines used is preferably 9: 1-1: 9, preferably 4: 1-1: 4. When the ratio of the aromatic primary diamine and secondary diamine is greater than 9: 1, the fluidity is poor, and molding is difficult. If the ratio is less than 1: 9, the moldability and water absorption resistance are good, but mechanical strength is inferior. The modified bismaleimide resin is superior in moisture resistance to conventional epoxy resins and bismaleimide resins and has a good wet ability with silica powder.

On the other hand, the silica powder of component 2) used in the present invention is a fused silica and crystalline silica having a median particle size of 5-30 μm, 50 to 80 parts by weight of the total composition is used. When using 50 parts by weight or less, the coefficient of thermal expansion increases, and in case of a sealing device, physical properties such as heat resistance, crack resistance, and moisture resistance decrease. When is cut or severe, sealing becomes impossible.

Further, the silicone oil of component 3) used in the present invention may be a liquid compound at room temperature while the unit structure of (Si-O) is formed in a repeated structure, for example, dimethyl silicone oil or methylphenyl. Silicone oil etc. are mentioned, The characteristics of these silicone oils may be changed somewhat.

That is, polydiorgano siloxane oil, fluoro silicone oil, silicone polyether copolymer oil, alkyl modified silicone oil, fatty acid modified silicone oil, amino modified silicone oil, epoxy modified silicone oil, etc. can also be used.

According to the present invention, it is preferable that the viscosity is 500-1,000,000 CPS at 25 ° C. in the silicone oil, and in particular, amino-modified silicone oil having an amine function has the best thermal shock resistance. The blending ratio of the silicone oil 3) is generally 0.8-25 parts by weight, preferably 1.3-5.0 parts by weight. If the blending ratio is less than 0.8 parts by weight, the improvement effect of moisture resistance, thermal stress resistance, thermal shock resistance, etc. is not sufficient, on the contrary, when 25 parts by weight or more, the processing molding is lowered.

The polyimide resin composition for sealing a semiconductor device of the present invention contains the above-mentioned 1), 2) and 3) components as essential components and dicumyl peroxide and di-tert- for the purpose of promoting the curing rate during molding. Butyl peroxide, α, α'-bis (tert-butylperoxyisopropyl) benzene, 4,4'-di-tert-butylperoxy-n-butylvaleride, 1,1'-di-tert-butyl Peroxides such as peroxy-3, 3, 5-trimethyl cyclohexane, amidazole, 2-methylimidazole, 1,2-dimethylimidazole, 2-phenylimidazole, 2-ethyl imidazole, Imidazoles such as 2-ethyl-4-methylimidazole and organic phosphine such as triphenylphosphine, tributylphosphine, dimethylphosphine, triethylamine, diethylene triamine, triethylene tetraamine, N Amine compounds such as amino-ethyl piperazine and mexylenediamine may be used alone or in combination of two or more thereof. According to the present invention, the blending ratio of such a curing accelerator is generally preferably 0.1 to 5 parts by weight, and most preferably 0.3 to 2 parts by weight based on the precursor. If the blending ratio is less than 0.1 parts by weight, the curing rate is slow, and when more than 5 parts by weight, moisture resistance may deteriorate.

In the composition of the present invention, release agents such as natural waxes, higher fatty acids and metal salts or paraffins thereof, epoxysilanes, vinylsilanes, inosilanes, borane compounds, alkoxy titarate compounds, aluminum chelate compounds, and the like. It is preferable to mix | blend and use a coupling agent, coloring agents, such as carbon black, in 10 weight part or less.

On the other hand, the manufacturing method of the polyimide resin composition for semiconductor element sealing of this invention is demonstrated in detail as follows.

In the composition of the present invention, each of the above-mentioned compositions is pulverized and mixed uniformly using a mixer such as a Henschel mixer, and melted and kneaded with a heating roller, a heating kneader, a heat extruder, etc. to cool the B-staged resin again. Afterwards, it can be finely pulverized and mixed with a special mixer, or prepared by combining each of these methods as appropriate.

When sealing various semiconductors by the transfer molding molding method using the polyimide resin composition of the present invention, it satisfies general characteristics such as heat resistance, thermal conductivity, and mechanical strength, and obtains excellent thermal stress resistance, moisture resistance, and optimum fluidity. Can be.

Hereinafter, the present invention will be described in more detail with reference to Preparation Examples, Examples and Comparative Examples. In the production examples, examples and comparative examples, all parts represent parts by weight.

[Production Example 1]

11.3 g of N, N'-dimethyl-4,4'-diamino diphenylmethane (0.05 mol), 9.9 g of methylene dianiline (0.05 mol) and 89.5 g of N in a three-necked flask with stirrer and thermometer .N'-4,4'-diphenylmethane bismaleimide (0.25 mole) is added. Subsequently, the mixture was kept at 130 ° C. and continuously stirred with a stirrer to confirm that the solution became a clear solution. It was poured into an aluminum dish, cooled to room temperature, and then pulverized in a mortar to obtain a yellowish brown glossy powder. Hereinafter, this powder is called modified bismaleimide resin A.

The softening point and molecular weight of the resin powder were measured using a thermal analyzer and GPC, and the results are shown in Table 1.

[Production Example 2]

The same procedure as in Preparation Example 1 was repeated except that 5.65 g (0.025 mol) of N, N'-dimethyl-4,4'-diamino diphenylmethane and 14.85 g (0.075 mol) of methylene dianiline were used. Powder was obtained and this powder is called modified bismaleimide resin B below, and it tested similarly to manufacture example 1, and the result is shown in Table 2.

Production Example 3

Tan-brown powder was prepared in the same manner as in Preparation Example 1, except that 16.95 g (0.075 mol) of N, N'-dimethyl-4,4'-diamino diphenyl methane and 4.95 g (0.025 mol) of methylene dianiline were used. This powder was referred to as modified bismaleimide resin C below, and was tested in the same manner as in Production Example 1, and the results are shown in Table 2.

[Production Example 4]

Except for using 19.8 g (0.1 mol) of methylenedianiline as the primary amine, the same procedure as in Preparation Example 1 was carried out to obtain a yellowish-brown powder, hereinafter referred to as modified bismaleimide resin D, The same test was performed and the results are shown in Table 1.

TABLE 1

Example 1

95 parts of modified bismaleimide resin A, 233.3 parts of melted silica as an inorganic filler, 5 parts of amino-modified dimethyl silicone oil (viscosity 10,000 CPS at 25 ° C), 1 part of dicumyl peroxide and 0.5 parts of imidazole as a curing accelerator, and silica powder 2 parts of an aminosilane-based coupling agent for surface treatment of 1, 1.5 parts of canuba wax as a release agent, and 0.5 parts of carbon black as a colorant were uniformly blended in a mixer, kneaded with two shafted rollers at 80-110 ° C., and then cooled. It grind | pulverizes and tablets, and manufactures the polyimide resin composition for semiconductor element sealing of this invention.

The characteristics of the composition obtained as described above were measured after the spiral, and a specimen for evaluation of physical properties was prepared using a low pressure transfer molding machine, and after curing for 8 hours at 200 ° C., the physical properties were measured and the properties thereof are shown in Table 2.

Spiral after measurement method is a known measurement method using a spiral mold measured in accordance with EMMI-1-66 (Epoxy Molding Material Institute: ASTM D-790), the coefficient of thermal expansion and glass transition temperature TMA (Thermomechanical) Analysis) was used.

Example 2

In Example 1, the composition of the present invention was prepared in the same manner as in Example 1, except that 5 parts of epoxy-modified dimethyl silicone oil was used instead of 5 parts of the amino-modified dimethyl silicone oil, and the evaluation test was carried out in the same manner as in Example 1. The results are shown in Table 2.

Example 3

In Example 1, the composition of the present invention was prepared in the same manner as in Example 1 except that 95 parts of the modified bismaleimide resin B was used instead of 95 parts of the modified bismaleimide resin A, and evaluated in the same manner as in Example 1. The test was conducted and the results are shown in Table 2.

Example 4

In Example 1, the composition of the present invention was prepared in the same manner as in Example 1 except that 95 parts of the modified bismaleimide resin C were used instead of 95 parts of the modified bismaleimide resin A, and evaluated in the same manner as in Example 1. The test was conducted and the results are shown in Table 2.

Comparative Example 1

A comparative composition was prepared in the same manner as in Example 1, except that 95 parts of the modified bismaleimide resin D were used instead of 95 parts of the modified bismaleimide resin A in Example 1, and an evaluation test was carried out in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 2

A comparative composition was prepared in the same manner as in Example 1, except that 95 parts of the modified bismaleimide resin A and 100 parts of the modified bismaleimide resin D were used instead of 5 parts of the amino modified dimethyl silicone oil in Example 1. The evaluation test was carried out in the same manner as in Example 1, and the results are shown in Table 2.

TABLE 2

Claims (6)

20-50 parts by weight of modified bismaleimide resin having an aromatic primary diamine and an aromatic secondary diamine added to bismaleimide having a molecular weight of 600-1600 and a softening point of 40-110 ° C., 50-80 parts by weight of silica powder, and silicone oil 0.8- A polyimide resin composition for semiconductor element sealing, comprising 25 parts by weight. The composition of claim 1, wherein the modified bismaleimide resin is Michael addition reaction of the modified bismaleimide with an aromatic primary diamine light aromatic secondary diamine in a molar ratio of 1.2: 1 to 4.0: 1. The composition according to claim 1, wherein the aromatic diamine added to the modified bismaleimide resin has a molar ratio of aromatic primary diamine and aromatic secondary diamine of 9: 1-1: 1. The composition of claim 1, wherein the silica powder is fused silica having a median particle size of 5-30 µm and crystalline silica. The composition of claim 1 wherein the silicone oil has an amine functional group or an epoxy functional group. The composition of claim 1 wherein the silicone oil has a viscosity of 500-1,000,000 CPS at 25 ° C.