JP2002299356A - Method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of efficiently manufacturing a semiconductor device which is superior in solar heat resistance, based on superior moldability with small fraction defective, by sealing semiconductor sealing resin equally, and a semiconductor device obtained by that manufacturing method. SOLUTION: An epoxy resin composition is molded to manufacture a semiconductor device by the semiconductor manufacturing method which heats the epoxy resin composition by high-frequency voltage application or electromagnetic waves, when sealing the semiconductor device by pressurizing and injecting the heated epoxy resin composition 4 into a mold 4 installed in a transfer molding machine by a plunger 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for efficiently manufacturing a resin-sealed semiconductor device.

[0002]

2. Description of the Related Art Electronic circuit components such as semiconductor devices are required to be sealed in order to prevent damage from external contaminants and external pressure.

Conventional methods for sealing a semiconductor device include hermetic sealing using metal or ceramics, and resin sealing using an epoxy resin, a silicone resin, or a phenol resin, which is a thermosetting resin. Recently, in addition to the good formability of the package,
Resin encapsulation using an epoxy resin composition that is also excellent in reducing manufacturing costs has become the main focus.

On the other hand, in recent years, there has been a demand for further downsizing, thinning, and cost reduction of electronic devices, and accordingly, electronic components have been mounted on a printed wiring board by surface mounting (SMT). . In this surface mounting method, the entire printed circuit board is heated to a high temperature of 210 to 260 ° C., which is the melting point of the solder, in the soldering process. And
At this time, if the sealing resin composition of the semiconductor device absorbs moisture, the moisture explosively evaporates to generate a peeled portion, and sometimes a crack runs to the outside of the package. The printed circuit board as a whole is defective because it is prone to failure and the reliability is significantly reduced.

At present, these solder heat resistance problems have been solved,
In order to prevent cracks from occurring in the encapsulated semiconductor device, a large amount of inorganic filler is blended into the epoxy resin composition. If the amount is increased unnecessarily, the fluidity is reduced due to an increase in the viscosity of the epoxy resin composition, so that a thin package cannot be molded, and a thick package has a problem of causing internal deformation. . Further, a molding machine for semiconductor encapsulation generally used at present raises the temperature of a semiconductor encapsulant by elevating the temperature of a mold and a plunger. In this method, the temperature of the portion in contact with the mold and the plunger is raised preferentially, and the temperature inside the tablet remains relatively lower than that outside, so that the temperature is unevenly raised and the epoxy resin in the molten state There is a problem that unevenness in viscosity occurs in the composition, and the filling property is affected particularly in a resin composition having a large amount of filler.

In order to solve this problem, molding must be carried out in a state where the viscosity is sufficiently reduced by uniform and rapid temperature rise of the epoxy resin.

[0007]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of studying to solve the problems in the prior art described above.

Accordingly, an object of the present invention is to improve the fluidity of a tablet by uniformly increasing the temperature of the tablet, and to improve the efficiency of a semiconductor device having an excellent soldering heat resistance under an excellent moldability with a low rejection rate. It is an object of the present invention to provide a method of manufacturing a semiconductor device and a semiconductor device manufactured by the manufacturing method.

[0009]

In order to achieve the above object, a method of manufacturing a semiconductor device according to the present invention mainly has the following configuration. That is, "The heated epoxy resin composition is pressurized and injected into a mold provided in a transfer molding machine by a plunger, and when the semiconductor device is sealed, the epoxy resin composition is subjected to high-frequency voltage or electromagnetic wave. Heating, curing and encapsulation by heating ".

Therefore, according to the method of manufacturing a semiconductor device of the present invention, it is possible to efficiently achieve both moldability and solder heat resistance, which have been difficult in the past.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration and effects of the present invention will be described below in detail.

First, the high frequency voltage in the present invention means a voltage having a frequency of 1 MHz to 300 GHz. High-frequency voltage is applied, high-frequency dielectric is generated, and the dielectric material in the material is vibrated, generating heat by friction.
Local heating can be performed by the electrodes.

The electromagnetic wave in the present invention is the electromagnetic wave whose frequency generally used for heating is 300 MHz or more.
Microwaves up to 300 GHz are desirable.

The characteristic of the application of the high-frequency voltage is that the power half-depth is deep, which is advantageous for uniformly heating a thick object. On the other hand, as a characteristic of the microwave, since it is an electromagnetic wave propagating in space, an object can be heated without direct contact of an electrode or a mold. This is advantageous for performing uniform heating even if the shape is complicated. Therefore, in the present invention, it is possible to select a usage method according to the characteristics of the substance according to the shape of the substance.

The principle of high-frequency voltage application or heating by electromagnetic waves will be described below. A dielectric substance in a substance is polarized by application of a high-frequency voltage or an electromagnetic wave, and an alternating (alternating) electric field can oscillate and rotate a polar dipole. At this time, friction acts between the molecules, and the temperature can be increased. Electromagnetic waves can penetrate into a substance, and by utilizing the property of being reflected by a metal, it is possible to uniformly heat the substance from the surrounding by covering the periphery of the substance with a metal. In the case of heating in the dielectric by applying a high-frequency voltage or irradiating an electromagnetic wave, the power per unit volume can be expressed by Equation 1. Where ε
_r × tanδ is called a loss factor and represents the ease of heating. This loss factor preferably lies between 0.01 and 1.

[0016]

(Equation 1) Next, a method for manufacturing a semiconductor device according to the present invention will be described with reference to the drawings.

FIGS. 1 and 2 are schematic views of a main part of a transfer molding machine used in the manufacturing method of the present invention. In FIGS. 1 and 2, reference numeral 2 denotes a mold of a transfer molding machine, into which a heated tablet 5 made of an epoxy resin composition is pressed and injected by a plunger 1. It is configured.

Here, the above-mentioned object is achieved by heating the tablet by applying a high-frequency voltage or an electromagnetic wave.
Specifically, in the case of FIG. 1, a high-frequency voltage is applied to the tablet in the mold 2 by a high-frequency dielectric electrode around the pot to heat the tablet. In the case of FIG. 2, a microwave waveguide is connected to the pot, and the tablet is heated by irradiating the tablet with electromagnetic waves. The frequency of the high frequency is 1 MHz to 300 MHz in the case of a high frequency, and a more preferable frequency is 8 MHz to 80 MHz. When using microwave, its frequency is 300MHZ
z to 300 GHz, more preferably 500M
Hz to 250 GHz. In the present invention, the application of the high-frequency voltage or the output of the electromagnetic wave is not particularly limited, but is preferably 10 to 3000 W, more preferably 100 to 200 W.
0W.

By applying a high-frequency voltage or heating by electromagnetic waves, for example, even if the content of the inorganic filler in the tablet 5 is high and its fluidity is insufficient, the temperature of the resin composition can be raised uniformly and quickly, The cavity 3 can be filled with the resin composition in a low-viscosity state, so that a normal package can be efficiently produced without being affected by the shape of a package such as a thin package or a thick package without generating defective products. It becomes possible to mold.

Next, the epoxy resin composition used in the present invention will be described.

The epoxy resin composition used in the present invention comprises:
Those containing the epoxy resin (A), the curing agent (B) and the inorganic filler (C) as components are preferred.

The epoxy resin (A) is not particularly limited to a resin having an epoxy group in a molecule.
Specific examples thereof include bisphenol A type epoxy resin, bisphenol C type epoxy resin, hydrogenated bisphenol type epoxy resin, bisphenol F type novolak resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, and alicyclic ring such as cyclopentadiene ring. Examples include a structure-containing epoxy resin, a biphenyl-type epoxy resin, and an epoxy-modified organosilicone. These epoxy resin compositions can be used alone or in combination of two or more.

The curing agent (B) can react with the epoxy resin (A) to cure it, and specific examples thereof include phenol novolak resin, cresol novolak resin, and phenol p-xylylene copolymer. Novolak resins synthesized from bisphenol A and resorcinol, various polyphenol compounds, acid anhydrides such as maleic anhydride, phthalic anhydride, and pyromellitic anhydride, and aromatic compounds such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Group amines and the like.

Depending on the application, two or more of these curing agents (B) may be used in combination, and the amount added is such that the chemical equivalent ratio to the epoxy resin (A) is 0.5 to 1.5 (curing agent equivalent /
(Epoxy equivalent) is preferable, and particularly preferably in the range of 0.8 to 1.2.

Specific examples of the inorganic filler (C) include:
Fused silica, crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, metal oxides such as antimony oxide, asbestos, glass fibers and glass spheres, among others. However, fused silica is particularly preferably used because it has a great effect of lowering the coefficient of thermal expansion and is effective in reducing the stress.

The compounding ratio of the inorganic filler (C) may be as high as 84 to 98% by weight based on the whole composition in consideration of solder heat resistance and moldability of the epoxy resin composition. it can.

The epoxy resin composition may further contain the following additives as required, in addition to the epoxy resin (A), the curing agent (B) and the inorganic filler (C). .

Various waxes such as polyethylene wax, carbana wax, montanic acid wax and magnesium stearate, fatty acid metal salts, long-chain fatty acids,
Various release agents such as metal salts of long-chain fatty acids, esters or amides of long-chain fatty acids and various modified silicone compounds,
Glycidyl ether of brominated bisphenol A, halogenated epoxy resin such as brominated cresol novolak,
Flame retardants such as organic halogen compounds and phosphorus compounds, various flame retardant aids such as antimony trioxide, diantimony tetroxide and antimony pentoxide, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, γ-glycide Xypropyltrimethoxysilane, γ-glycidoxypropylvinylethoxysilane,
γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, aminopropyltrimethoxysilane, amino Propyltriethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltriethoxysilane, γ-
Anilinopropyltrimethoxysilane, γ-anilinopropyltriethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane and N-β- (N-vinylbenzylaminoethyl)- Various silane coupling agents such as γ-aminopropyltriethoxysilane, triphenylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tri-a-tolylphosphine, tris- (2,6-
Various phosphine compounds such as dimethoxyenol) phosphine, various phosphonium salts such as tetraphenylphosphonium bromide, tetraethylphosphonium bromide, tetrabutylphosphonium bromide, tetraphenylphosphonium tetraphenylborate, tetraethylphosphonium tetraphenylborate and tetrabutylphosphonium tetraphenylborate, And imidazole, 1-methylimidazole, 2-methylimidazole, 1,2-dimethylimidazole, 1-phenylimidazole, 2-phenylimidazole, 1-benzylimidazole, 1,8-diaza-bicyclo- (5,4,
0) Undecene-7 (DBU), phenol of DBU,
DBU phenol novolak salt, DBU octyl salt, D
BUp-toluenesulfonate and 1,5-diaza-
Various curing accelerators such as various amine compounds such as bicyclo (4,3,0) nonene-5 (DBN); various coloring agents and pigments such as carbon black and iron oxide; silicone rubber; Nitrile rubber,
Various elastomers such as modified polybutadiene rubber, various thermoplastic resins such as polyethylene, and crosslinking agents such as organic peroxides.

The epoxy resin composition is prepared by mixing an epoxy resin (A), a curing agent (B), an inorganic filler (C) and other additives with, for example, a Banbury mixer or the like, and then mixing the mixture with a monoaxial or biaxial resin. It can be manufactured by melt-kneading using various kneaders such as an extruder, a kneader and a hot roll, and cooling and pulverizing or tableting.

Then, using the epoxy resin composition,
The semiconductor device obtained by sealing by the transfer molding method of the present invention has both excellent moldability and solder heat resistance,
It has ideal performance as a semiconductor device.

[0031]

EXAMPLES The effects of the present invention will be described more specifically with reference to examples and comparative examples. First, it will be shown that a tablet made of an epoxy resin composition can be uniformly heated by application of a high-frequency voltage or electromagnetic wave heating. In a tablet having the composition of Example 1 in Table 2, thermometers of a thermocouple made of alumel-chromel were arranged at the positions (two places) shown in FIG. Next, the change in the temperature of the tablet with and without the use of electromagnetic waves in the heated mold was examined. The results are shown in FIG. 4 and the comparative example is shown in FIG. Thus, it can be seen that the inside and outside of the tablet are uniformly heated by application of a high-frequency voltage or heating using electromagnetic waves. Irradiation of electromagnetic waves is performed using a magnetron with an initial output of 20
00W, from a direction 60 ° above the horizontal direction of the tablet. The mold temperature was set at 175 ° C.

Examples 1 to 12 and Comparative Examples 1 to 6 Dry blending was carried out using the raw materials shown in Table 1 at a composition ratio shown in Tables 2 to 5 using a mixer. This was melt-kneaded for 4 minutes in an extruder, cooled and pulverized to prepare an epoxy resin composition.

Table 1 shows the results of evaluating the performance of semiconductor devices obtained by molding each of the above epoxy resin compositions using the transfer molding machine shown in FIG. 1 according to the following evaluation criteria. Show.

The application of a high-frequency voltage or electromagnetic waves
A high frequency of MHz or a microwave of 2450 GHz was introduced into the pot portion to heat the resin composition. The output at this time was 2000W. In the comparative example, sealing was performed by a method in which a normal mold was maintained at a resin curing temperature of 175 ° C. without using high-frequency dielectric or microwave.

[Evaluation Criteria] Formability of Package: Exposed stage and unfilled package were visually observed for 50 packages each of 54-pin TSOP and 160-pin QFP, and the exposed stage and unfilled package were observed. The package was determined to be defective, and the defect rate was determined.
The internal voids of both packages were observed with an ultrasonic flaw detector, and the external voids were visually observed. The total was divided by 50, and the number of voids per package was shown as the number of voids.

Further, both packages were cut, the inclination of the stage was observed, and the average of each of the 50 packages was determined to determine the stage displacement.

Solder heat resistance: 54-pin TSOP and 160
85 ° C, 8 for 50 pin QFP packages
After humidification at 5% for 168 hours, the sample was heated in an IR reflow furnace at a maximum temperature of 245 ° C. Thereafter, the presence or absence of external cracks was examined by observation using an ultrasonic flaw detector, and the package containing the crack was determined as a defective package, and the ratio was defined as the solder heat resistance defective rate.

The details of the package used in this experiment are shown below. 54-pin TSOP: outer dimensions 10 × 22 × 1.0 mm, chip size 5 × 10 mm, die pad size 6 × 11 mm 160-pin QFP: outer dimensions 28 × 28 × 3.4 mm, chip size 12 × 12 mm, die pad size 13 × 13 mm

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

As is clear from the results of Tables 2 to 4, the semiconductor device obtained by the method of the present invention (Examples 1 to 12)
Comparative Example 1 not heated by high-frequency voltage application or electromagnetic wave
Compared with No. 6, even when the blending amount of the inorganic filler is high, the epoxy resin composition can be filled at a high density, and as a result, there is no void, stage displacement, chip, frame exposure, etc. With excellent moldability with less
A semiconductor device having excellent solder heat resistance can be obtained.

[0044]

As described above, according to the method of manufacturing a semiconductor device of the present invention, even if the amount of the inorganic filler is large and the fluidity of the epoxy resin composition is insufficient, the mold in the mold is not affected. The resin composition can be filled at a high density, and a normal package can be efficiently formed without generating defective products in common with the thin package and the thick package.

Further, since the content of the inorganic filler in the epoxy resin composition can be set high, a semiconductor device having excellent solder heat resistance can be obtained.

Therefore, according to the method of manufacturing a semiconductor device of the present invention, it is possible to efficiently achieve both the moldability and the soldering heat resistance, which were conventionally difficult.

[Brief description of the drawings] [Explanation of symbols]

 1. Plunger 2. Sealing mold 3. Cavity 4. Pot 5. Epoxy resin composition 6. 6. Frame and semiconductor element 7. High frequency voltage electrode Magnetron

FIG. 1 is a schematic cross-sectional view of a main part of an example of a transfer molding machine used in a production method of the present invention.

FIG. 2 is a schematic sectional view of a main part of a transfer molding machine used in an embodiment of the present invention.

FIG. 3 is a schematic sectional view of a tablet used in an experiment showing uniform heating by application of a high-frequency voltage or electromagnetic waves.

FIG. 4 is a graph of experimental results showing uniform heating by electromagnetic waves.

FIG. 5 is a graph of experimental results showing non-uniform heating by a conventional heating method.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29C 45/76 B29C 45/76 H01L 23/29 B29K 63:00 23/31 B29L 31:34 // B29K 63 : 00 H01L 23/30 RB29L 31:34 F term (reference) 4F206 AA39 AD18 AH37 AK10 AK11 AR16 AR20 JA02 JB12 JB17 JD04 JE06 JM04 JM16 JN43 4M109 AA01 CA21 EA03 EB02 EB04 EB06 EB07 EB07 EB09 EB09

Claims (4)

[Claims] An epoxy resin composition is heated and injected into a mold provided in a transfer molding apparatus with a plunger to seal a semiconductor device. Alternatively, a method for manufacturing a semiconductor device, wherein heating is performed by electromagnetic waves. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the epoxy resin composition is heated, cured and sealed by a high frequency voltage or an electromagnetic wave in a mold pot. 3. The power supply frequency of the high-frequency voltage is 1 MHz to 3 MHz.
3. The method for manufacturing a semiconductor device according to claim 1, wherein the frequency is 00 MHz. 4. The electromagnetic wave has a frequency of 300 MHz to 300 MHz.
The method according to claim 1, wherein the frequency is GHz.