JPS6331103B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a semiconductor device encapsulated with an epoxy resin composition containing silicon carbide-based sintered body powder as a filler. Related to semiconductor devices. In recent years, resin encapsulation methods, which use thermosetting resin molding materials to encapsulate semiconductor elements, resistors, capacitors, coils, and other electronic circuit components, have been widely adopted, contributing greatly to production efficiency and economy. . As the material, epoxy resin molding materials for low-pressure molding are widely used. Now, for example, these resin-sealed TRS,
Semiconductor devices such as ICs and LSIs are cheaper than hermetically sealed products made of glass, ceramics, metals, etc., but they are slightly inferior in reliability, moisture resistance, high-temperature operation characteristics, etc. Therefore, various studies have been made to improve their reliability. In addition, recently, large output TRS,
As ICs, LSIs, etc. are in demand, it has become especially necessary to improve the thermal conductivity of mold resins. Therefore, the present inventors developed a method with particularly high output.
We have been conducting research to find a sealing resin that has high thermal conductivity and can be applied to TRS, IC, LSI, etc., and also meets the requirements for reliability such as moisture resistance. In order to make the sealing resin highly thermally conductive, a method of blending an inorganic filler with high thermal conductivity is generally adopted. Such fillers include crystalline silica,
Examples include powders of alumina, zirconium silicate, beryllium oxide, magnesium oxide, mullite, silicon carbide, and the like. However, each of them has advantages and disadvantages in practical terms. That is, crystalline silica has a large coefficient of thermal expansion, alumina, zirconium silicate, etc. have empirically shown a tendency to delay the curing of epoxy resins, and magnesium oxide is hygroscopic. For this reason, commercially available sealing resin products that are said to have high thermal conductivity generally use a combination of crystalline silica powder and amorphous silica powder with a small coefficient of linear expansion, so-called quartz glass powder, to achieve thermal conductivity. It seems that a compromise has been made between this and the coefficient of thermal expansion. By discovering a sealing resin with high thermal conductivity and a small coefficient of linear expansion, the present inventors have discovered a resin-sealed semiconductor device that meets the above-mentioned requirements and has excellent moisture resistance and high-temperature operating characteristics. We proceeded with the study with the idea that it would be possible to produce a They focused on silicon carbide, but this material had a resistivity of 10 Ω-cm and was therefore unsuitable as a filler for sealing resins.
However, in another study, it was discovered that a sintered body made of silicon carbide mixed with at least one of beryllium oxide and boron nitride is an insulator with a specific resistance of 10 ¹⁰ Ω-cm or more. It was found that the expected properties could be obtained by adding the powder obtained by crushing this sintered body to an epoxy resin composition as a filler. The present invention has been achieved based on the above-mentioned progress, and an object of the present invention is to provide a highly reliable resin-sealed semiconductor device. Its feature is that it is sealed with an epoxy resin composition containing silicon carbide as a main component and sintered powder containing at least one of beryllium oxide and boron nitride as a filler. It is. The composition of the filler is related to the required specific resistance value and is determined to provide a value of 10 ¹⁰ Ω-cm or more. Specifically, it is desirable that at least 2 parts by weight of at least one of beryllium oxide and boron nitride be contained per 100 parts by weight of silicon carbide. After the compounds are thoroughly mixed, they are pressure sintered under vacuum at about 2000° C., then ground and filled into an epoxy resin composition. In the present invention, the epoxy resin composition contains an epoxy resin and its curing agent as main components, and may further contain a curing accelerator and others as necessary. The epoxy resin is not particularly limited, and a wide variety of known epoxy compounds can be used. For example, glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenol novolak, and cresol novolak, glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol, phthalic acid, isophthalic acid, and tetrahydrocarbon. Glycidyl-type (including methylglycidyl-type) epoxy resins such as glycidyl esters of carboxylic acids such as phthalic acid, aniline, isocyanuric acid, etc. in which the active hydrogen bonded to the nitrogen atom is replaced with a glycidyl group, and olefin bonds within the molecule. vinylcyclohexene diepoxide obtained by epoxidizing with peracid etc., 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3 - So-called alicyclic epoxides such as 4-epoxy) cyclohexane-m-dioxane are used. Also,
As the curing agent, a known curing agent for epoxy resins can be used. To give some examples, for example,
Maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, tetrachlorophthalic anhydride, endodichloromethylenetetraanhydride So-called acid anhydride curing agents such as chlorophthalic acid, tetrabromophthalic anhydride, trimellitic anhydride, cyclopentanetetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, pyromellitic dianhydride, diaminodiphenylmethane , diaminodiphenyl ether, diaminodiphenyl sulfone, benzidine, dianisidine, phenylenediamine, methylenebis(o-chloroaniline),
Aromatic amines such as 3,3'-dicarboxylbenzidine, 3,3'-dicarboxyldiaminodiphenylmethane, phenol novolak, cresol novolak, condensates of phenol, cresol, etc., and paraxylylene dimethoxide, There are so-called polyhydric phenol curing agents having a phenolic hydroxyl group, such as condensates of phenol, cresol, etc., and diphenyl ether, formaldehyde, and the like. Furthermore, isocyanates that react with epoxy resins to produce oxadoridone rings and harden, and also trimerize and polymerize themselves;
Examples include tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, hexane-1,6-diisocyanate, naphthalene diisocyanate, polymethylene polyphenylene polyisocyanate, and dimerized or trimerized products of the above isocyanates. . In addition, maleimides synthesized from amines such as diaminodiphenylmethane and polymethylene polyphenylene polyamine and maleic anhydride not only polymerize themselves, but also react with the amic acid remaining in the molecule with the epoxy resin. It hardens and can be used as a curing agent for epoxy resins. Furthermore, adducts of the above maleimides and polyamines can also be used as curing agents for epoxy resins. As the curing accelerator, all known ones useful for epoxy resins can be used. In particular, compounds with excellent latent properties include tetra-substituted phosphonium/tetra-substituted borate, tetra-substituted arsonium/tetra-substituted borate, tetra-substituted ammonium/tetra-substituted borate, borate compounds of various imidazole compounds, and reaction products of dimethylaminoethanol and anhydride. It is preferable to use In addition, various imidazole compounds and their derivatives are also effective. Furthermore, two or more of these curing accelerators may be used in combination. Furthermore, in order to transfer mold semiconductor devices such as transistors, ICs, and LSIs, other inorganic fillers can be used in the epoxy resin composition of the present invention, such as calcium carbonate and silica powder. , zirconium silicate, calcium silicate, quartz glass powder, talc, clay, mica, glass fiber powder, etc. are useful, and two or more of these may be used in combination as necessary. Further, as other additives, a mold release agent, a coloring agent, a surface coupling agent, a flame retardant aid, etc. may be added. In preparing a molding material for encapsulating a semiconductor device made of an epoxy resin composition containing a filler containing silicon carbide as a main component, each of the solid component materials is pulverized and then sufficiently mixed in the desired ratio. Mix. For mixing, conventional mixing equipment such as a mixing roll machine, kneader, ribbon mixer, ball mill, etc. can be used. By directly applying the obtained mixture to transfer molding, a highly reliable resin-sealed semiconductor device can be manufactured. Next, the present invention will be explained with reference to Examples. Example 1 Preparation of filler. 100 parts by weight of 98% pure silicon carbide powder (average particle size 2 μm) and 3 parts by weight beryllium oxide powder (average particle size 2 μm) were carefully mixed and then temporarily formed into a disk with a diameter of 50 mm. This temporary molded product was placed in a graphite jig, and using a vacuum hot press device, it was heated under a reduced pressure of 10 ^-3 to 10 ^-5 Torr and at a pressure of 200 Kg/cm ² .
It was sintered at a temperature of 2000℃. The sintered body was coarsely pulverized and then finely pulverized (average particle size: 10 μm) using an alumina ball mill. Example 2 Phenol novolac epoxy resin (epoxy equivalent weight 225), tetrahydrophthalic anhydride as a curing agent, phenol novolac (molecular weight approximately 800) or diaminodiphenylmethane, 2-undecylimidazole as a curing accelerator, mold release agent as Stearic acid or Montana wax, carbon black as a colorant, silicon carbide-based sintered body powder described in Example 1 as a filler, crystalline silica, amorphous silica,
Alumina or zirconium silicate powder was blended according to the composition shown in Table 1 (expressed in parts by weight) and kneaded using hot rolls (70 to 80°C). After cooling, the kneaded material was pulverized to prepare a molding material. Regarding the molding material, 180℃, 70Kg/cm ² pressure, 2.5
In addition to measuring the formability (spiral flow) under the conditions of 10 minutes, the test piece was molded and the hardness at the time of heating (Barcol No.
935, 2.5 minute value), linear expansion coefficient, and thermal conductivity were measured.
Their values are shown in Table 1. Using the compositions of Example Samples No. 2, 4, and 5 and Comparative Example Samples 1 and 4, MOS and LSI were sealed by transfer molding according to the molding conditions described above. The moisture resistance and high temperature operating characteristics of the sealed product were examined using the following method. Moisture resistance test After being left in water vapor at 120°C and 2 atm for 1000 hours, the corrosion status of the aluminum wiring of the element is examined and evaluated based on the corrosion incidence rate. High-temperature operating characteristics A performance test is performed after being left at a temperature of 180°C for 1000 hours, and the rate of malfunctioning elements that occur due to the leaving is evaluated. The results are shown in Table 2. As is clear from Tables 1 and 2, the cured products of the epoxy resin compositions of Examples have high thermal conductivity and low coefficient of linear thermal expansion, and MOS and LSI products sealed using the cured products have high thermal conductivity and low coefficient of linear thermal expansion. has excellent reliability.

【table】

【table】

[Table] Example 6 (1) Preparation of filler. After carefully mixing 100 parts by weight of 98% pure silicon carbide powder (average particle size 2 μm) and 3 parts by weight of 95% pure nitrogen boron powder (average particle size 0.5 μm), they were temporarily formed into a disk shape with a diameter of 50 mm. did. Place this temporary molded product in a graphite jig and heat it to 10 ^-3 ~
Under reduced pressure of 10 ^-5 Torr, pressure 200Kg/cm ² , temperature approx.
Sintered at 2000℃. After cooling, the sintered body was coarsely pulverized, and further finely pulverized (average particle size: 16 μm) using an alumina ball mill. (2) Adjustment of molding materials. Similar to Examples 2, 4 and 5, phenol novolak resin (epoxy equivalent
225) 100 parts by weight, 55 parts by weight of phenol novolac resin (molecular weight approximately 800) as a curing agent, 3 parts by weight of 2-undecylimidazole as a curing accelerator, and 2 parts by weight each of stearic acid and Montana wax as mold release agents. , using 1 part by weight of carbon black as a coloring agent and 430 parts by weight of the above silicon carbide sintered body powder as a filler,
After premixing each material, further heat roll (70
~80°C). After cooling, the kneaded material was pulverized to prepare a molding material. (3) Characteristics of molding materials. Regarding the above molding material, mold temperature 180℃, molding pressure 70Kg/cm ² , curing time 2.5
In addition to measuring the moldability (spiral flow) under the conditions of 30 minutes, we also measured the hot hardness of the molded product (Barcol No.
935), linear expansion coefficient, and thermal conductivity were measured. (4) Characteristics of sealed products. Using the above molding material,
MOSLSI was sealed by transfer molding under the same conditions as above, and the moisture resistance and high temperature operating characteristics of the sealed product were evaluated in the same manner as in Example 2. The results are shown in Table 3.

[Table] As is clear from Table 3, by using the epoxy resin composition of the present invention, a resin-sealed semiconductor device with excellent reliability can be provided.

Claims (1)

[Scope of Claims] 1. Sealing using an epoxy resin composition containing silicon carbide as a main component and containing powder of a sintered body containing at least one of beryllium oxide and boron nitride as a filler. A resin-sealed semiconductor device characterized by: 2. The semiconductor device according to claim 1, wherein the filler is a sintered powder containing at least 2 parts by weight of at least one of beryllium oxide and boron nitride based on 100 parts by weight of silicon carbide.