JP2000040708A - Semiconductor sealing resin pellet, manufacture thereof and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve measuring property and to suppress the occurrence of voids in a molded product by specifying the weight of one particle in a semiconductor sealing resin pellet. SOLUTION: A semiconductor sealing resin pellet is manufactured by having a semiconductor sealing resin component, wherein epoxy resin, hardening agent, inorganic filling material and the like are filled is fused and kneaded, thereafter, the component is discharged, cooled and crushed. Then, the product is screened, and the resin is cut out. The epoxy resin is such that it has two or more epoxy bases in one molecule, the blending equivalent ratio of the hardening agent with the epoxy resin is set to 0.7-1.5, and the rate of the inorganic filling material is set to 75% or more of the overall resin component. Furthermore, the weight of one pellet particle is set to 0.1-30 mg. If the weight exceeds 30 mg, the measuring property and resin using efficiency are decreased, and voids occur in molding. If the weight is less than 0.1 mg, defects occur in measuring by the effect of static electricity, and handling and working environment may be impaired.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin pellet for semiconductor encapsulation which is excellent in weighability and has few voids in a molded article, a method for producing the same, and a semiconductor element sealed using the resin pellet for semiconductor encapsulation. The present invention relates to a stopped semiconductor device.

[0002]

2. Description of the Related Art Conventionally, a transfer molding method using a sealing material tablet has been widely used for sealing a semiconductor element with a resin. However, since packages of various sizes have been used in recent years, tablets of various sizes corresponding to the packages are required, and a great deal of labor and cost are spent on the management of the tablets. Therefore, as a means of reducing the tablet size management, a method of forming a tablet corresponding to a plurality of sizes using a tablet of an unnecessarily large size has been adopted, but the use efficiency of the sealing material is poor. There is.

Therefore, a method has been proposed in which a semiconductor element is sealed with a resin by using powder or pellets before tableting. However, when powder or pellets are used, the porosity is larger than that of tablets,
There is a problem that voids are easily generated in the molded product.

[0004]

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.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a resin pellet for semiconductor encapsulation which is excellent in weighability and has few voids in a molded product, a method for producing the same, and a semiconductor element encapsulated by using the resin pellet for semiconductor encapsulation. It is an object of the present invention to provide a semiconductor device comprising:

[0006]

Means for Solving the Problems To solve the above problems, the resin pellet for semiconductor encapsulation of the present invention mainly has the following constitution. That is, the weight of one grain is 0.1 to 30 mg
Is a resin pellet for semiconductor encapsulation.

The method for producing a resin pellet for semiconductor encapsulation of the present invention mainly has the following configuration. That is,
A method for producing a resin pellet for semiconductor encapsulation, comprising cooling, pulverizing, and sieving the resin discharged from an extruder when producing the resin pellet for encapsulating a semiconductor.

The semiconductor device according to the present invention mainly has the following configuration. That is, the present invention is a semiconductor device in which a semiconductor element is sealed using the resin pellet for semiconductor sealing.

[0009]

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

The semiconductor encapsulating resin pellet of the present invention is generally prepared by melt-kneading a semiconductor encapsulating resin composition containing an epoxy resin (A), a curing agent (B), an inorganic filler (C) and the like. Then, it is manufactured by discharging, cooling, pulverizing, sieving, or cutting the resin. Hereinafter, the resin composition for semiconductor encapsulation will be described.

The epoxy resin (A) according to the present invention comprises 1
It is not particularly limited as long as it has two or more epoxy groups in the molecule, and specific examples thereof include, for example, cresol novolak type epoxy resin, phenol novolak type epoxy resin, phenol aralkyl type epoxy resin,
Naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocycle Examples thereof include a formula epoxy resin, a spiro ring-containing epoxy resin, and a halogenated epoxy resin, and two or more of these may be used in combination.

Particularly preferred examples of the epoxy resin (A) include 4,4'-bis (2,3-epoxypropoxy) biphenyl and 4,4'-bis (2,3-epoxypropoxy) -3. Biphenyl type epoxy resin such as 1,3 ′, 5,5′-tetramethylbiphenyl;
Di (2,3-epoxypropoxy) naphthalene, 1,6
Naphthalene-type epoxy resins such as -di (2,3-epoxypropoxy) naphthalene, 3-t-butyl-2,4 '
-Bis (2,3-epoxypropoxy) -3 ′, 5 ′,
6-trimethylstilbene, 3-t-butyl-4,4 '
-Bis (2,3-epoxypropoxy) -3 ′, 5 ′,
6-trimethylstilbene, 4,4′-bis (2,3-
Epoxypropoxy) stilbene, 4,4'-bis (2,3-epoxypropoxy) -3,3'-di-t-
Butyl-6,6'-dimethylstilbene, 2,2'-bis (2,3-epoxypropoxy) -3,3'-di-t
-Butyl-6,6'-dimethylstilbene, 2,4'-
Bis (2,3-epoxypropoxy) -3,3'-di-
t-butyl-6,6'-dimethylstilbene, 4,4 '
-Bis (2,3-epoxypropoxy) -3,3'5
Examples include stilbene-type epoxy resins such as 5'-tetramethylstilbene, dicyclopentadiene-type epoxy resins, and cresol novolak-type epoxy resins. It is more preferable to mix these epoxy resins in an amount of 60 to 100% by weight of the total epoxy resin. .

The curing agent (B) in the present invention may be any compound as long as it is a compound that reacts with the epoxy resin. When it is a cured product, it has a low water absorption and is a phenol compound having a hydroxyl group in the molecule. Is preferably used. Specific examples of the phenol compound include a phenol aralkyl resin, a naphtho aralkyl resin, a terpene skeleton-containing phenol compound, a dicyclopentadiene skeleton-containing phenol compound, a phenol novolak resin, a cresol novolak resin, and a naphtho-novolak resin. Lunovolak resin, tris (hydroxyphenyl) methane, 1,1,2-tris (hydroxyphenyl) ethane, 1,1,3-tris (hydroxyphenyl) propane, catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol
And the like. Among them, it is particularly preferable to include at least one selected from a phenol aralkyl resin, a naphtho aralkyl resin, a terpene skeleton-containing phenol compound and a dicyclopentadiene skeleton-containing phenol compound. It is preferable in terms of suppressing generation.

Equivalent ratio of epoxy resin (A) to curing agent (B) (molar ratio of hydroxyl group to epoxy group)
Is usually 0.5 to 2.0, preferably 0.7 to 1.
5 The compounding amount of the epoxy resin (A) and the curing agent (B) is preferably 5 to 20% by weight, more preferably 5 to 15% by weight, for both the epoxy resin (A) and the curing agent (B).
% By weight.

As the inorganic filler (C) in the present invention, amorphous silica, crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, silicon nitride, magnesium aluminum oxide, zirconia, zircon,
Clay, talc, calcium silicate, titanium oxide, antimony oxide, asbestos, glass fiber, calcium sulfate,
Aluminum nitride and the like can be used, and those having an arbitrary shape such as a spherical shape, a crushed shape, and a fibrous shape can be used. Inorganic filler (C)
Preferred specific examples of amorphous silica, crystalline silica,
Alumina.

The proportion of the inorganic filler (C) is preferably at least 75% by weight of the whole resin composition.

In the present invention, it is preferable to mix a coupling agent such as a silane coupling agent from the viewpoint of reliability when sealing a semiconductor device. The coupling agent may be added as it is, or may be added after the surface treatment of the inorganic filler (C). As a coupling agent,
A silane coupling agent in which an organic group having a functional group such as epoxysilane, aminosilane, mercaptosilane, or ureidosilane is bonded to a silicon atom and a hydrolyzable group such as an alkoxy group is directly bonded to the silicon atom is preferably used. More than one species may be used in combination. In addition, the amount of the coupling agent is usually relative to the entire epoxy resin composition,
Preferably it is 0.1 to 2% by weight.

In the present invention, a curing accelerator can be further added. The curing accelerator used is not particularly limited as long as it promotes the reaction between the epoxy resin and the curing agent. Specific examples thereof include phosphine compounds such as triphenylphosphine, tributylphosphine, and tri (p-methylphenyl) phosphine. , 2-methylimidazo-
, Imidazole compounds such as 2-phenylimidazole, 2-phenyl-4-methylimidazole and 2-heptadecylimidazole; tertiary amines such as triethylamine, benzyldimethylamine and α-methylbenzylamine Compound, 1,8-diazabicyclo (5,4,0) undecene-7,1,5-diazabicyclo (4,3,0)
Nonene-5,7-methyl-1,5,7-triazabicyclo (4,4,0) decene-5 and the like.

In the present invention, a bromo compound may be blended. The bromo compound is usually added as a flame retardant to the epoxy resin composition for semiconductor encapsulation, and is not particularly limited. Preferred specific examples are brominated bisphenol A type epoxy resin, brominated epoxy resin such as brominated phenol novolak type epoxy resin, brominated polycarbonate resin, brominated polystyrene resin,
Brominated polyphenylene oxide resin, tetrabromobisphenol A, decabromodiphenyl ether and the like can be mentioned. Above all, brominated epoxy resins such as brominated bisphenol A type epoxy resin and brominated phenol novolak type epoxy resin have excellent moldability. Is preferred.

In the present invention, an antimony compound can be blended. This is usually added as a flame retardant aid to the epoxy resin composition for semiconductor encapsulation, and is not particularly limited, and a known one can be used. Preferred specific examples of the antimony compound include antimony trioxide, antimony tetroxide, and antimony pentoxide.

In the present invention, elastomers such as silicone rubber, olefin copolymer, modified nitrile rubber, modified polybutadiene rubber, and modified silicone oil, long chain fatty acids, metal salts of long chain fatty acids, esters of long chain fatty acids, A release agent such as an amide of a long-chain fatty acid or paraffin wax can also be blended.

In the present invention, other additives such as colorants such as carbon black and iron oxide, hydrotalcites,
An ion scavenger such as bismuth, a thermoplastic resin such as polyethylene and polypropylene, and a crosslinking agent such as an organic peroxide can be optionally added.

The resin pellet for semiconductor encapsulation of the present invention is usually used as an aggregate composed of a plurality of pellets, and when encapsulating a semiconductor with resin, a plurality of, preferably 10 or more, per pot are formed in one molding cycle. Molding is performed using more than one piece.

The weight of one pellet is 30 mg or less, preferably 15 mg or less. The weight of one pellet is 3
If it exceeds 0 mg, the weighing property and the resin use efficiency will be poor, and it will be difficult to reduce the voids when molding with a plurality of pieces, and voids will easily occur in the molded article. The weight of one pellet is 0.1 mg or more, preferably 3 m
g or more. If the weight of one pellet is less than 0.1 mg, a problem occurs at the time of weighing due to the influence of static electricity or the like, and there is a problem that the handling and working environment are impaired.

The shape of the pellets is not particularly limited, and includes, for example, a spherical shape, a rugby ball shape, a cylindrical shape, a prismatic shape, and the like. Classification is less likely to occur and the bulk density is constant, so that it is easy to stably supply the molding machine with a constant volume or a constant weight, which is preferable from the viewpoint of weighability. In addition, heat is easily transmitted uniformly, there is no occurrence of uneven flow during molding, and problems such as stage displacement, wire flow, and voids are unlikely to occur.

The viscosity behavior of a thermosetting resin sealing material under a high-temperature atmosphere is generally as follows. When the thermosetting resin sealing material is placed in a high-temperature atmosphere, melting starts immediately thereafter, and the viscosity gradually decreases to reach the minimum viscosity η. However, the time during which the viscosity stays at the minimum viscosity η is short, after which the viscosity of the resin gradually increases due to the curing reaction of the resin, and finally the resin is cured. In the present invention, the time from immediately after being placed in the 175 ° C. atmosphere until it reaches 1.2 times the minimum viscosity η for the first time means the behavior of the viscosity change at 175 ° C. immediately after the pellet is placed in the 175 ° C. atmosphere. Means the time required to reach 1.2 times the minimum viscosity η at the stage where the viscosity is lowered. In the present invention, the minimum viscosity η of 1.2
It is preferable that the time to reach the doubling time is 15 seconds or less from the viewpoint of suppressing generation of voids and improving the molding cycle property.

In the present invention, the time within the range of the minimum viscosity η to η × 1.2 at 175 ° C. means that the viscosity decreases immediately after the pellet is placed in an atmosphere at 175 ° C.
It refers to the time from when the value becomes × 1.2, the value passes through the minimum viscosity, and reaches η × 1.2 again due to the increase in viscosity. 175 ° C
The time during which the viscosity under the atmosphere is in the range of the minimum viscosity η to η × 1.2 is preferably 4 seconds or more from the viewpoint of suppressing the generation of voids. If the time is less than 4 seconds, voids are likely to be generated due to a rapid change in viscosity, which is not preferable.

The time corresponding to the above-mentioned change in the viscosity of the pellet is as follows: the set temperature is 175 ° C., and the nozzle diameter / length is 0.5 /
Using a Koka type flow tester (manufactured by Shimadzu Corporation) set to 1.0 mm and a load of 10 kg, about 2.5
After the pellets of g are supplied to the apparatus, the pressure can be promptly applied by a plunger, and the viscosity change with respect to time can be determined.

The viscosity of the pellet is not particularly limited as long as the semiconductor element can be sealed. However, the minimum viscosity at 175 ° C. is 40 Pa · s from the viewpoint of generation of voids and load on a molding machine.
sec or less is preferable.

The method for producing the resin pellet for semiconductor encapsulation of the present invention is not particularly limited, but the epoxy resin (A), the curing agent (B), the inorganic filler (C) and the like are melt-kneaded in a melt-kneading apparatus. After cooling and pulverizing, a method of sieving, a method of extruding in a gut shape from a melt kneading device, a method of cutting,
A method of hot-cutting the resin discharged from the melt-kneading apparatus is preferable. From the viewpoint of heat history, a method of sieving and a method of extruding in a gut shape and then cutting are particularly preferred.

The kneading temperature of the resin composition for semiconductor encapsulation is 60.
To 140 ° C, more preferably 60 ° C to 120 ° C. As the melt kneading device, a known kneading machine such as a Banbury mixer, a kneader, a roll, a single screw or a twin screw extruder can be used. The melt kneading apparatus is preferably provided with a vent device so as not to leave voids in the melt discharge. In the screw arrangement, it is preferable to use a kneading screw or a dalmage screw in order to uniformly knead the resin or the inorganic filler.

In the method of sieving the pulverized resin, as long as the weight of the pellets is 0.1 to 30 mg, there is no limitation on the size of the sieve to be used.
What is necessary is just to sieve it so that an opening may be 0.25 mm.

In the method of cutting the gut-like material extruded from the melt-kneading apparatus, it can be cut into pellets by a known method such as a cutter. Further, if necessary, the gut-like material may be cooled by a known method such as cold air or a cooling belt.

In the method of hot cutting the discharged resin, the cut pellets may be cooled if necessary.

As a method for manufacturing a semiconductor device by sealing a semiconductor element using the resin pellet for semiconductor sealing of the present invention, a known method such as a low-pressure transfer molding method, an injection molding method, and a compression molding method can be used. It is. As molding conditions, for example, a resin pellet for semiconductor encapsulation is molded at a molding temperature of 150 to 200 ° C., a pressure of 5 to 15 MPa, and a molding time of 3
A semiconductor device is manufactured by molding in 0 to 300 seconds to obtain a cured product of the sealing resin composition.

[0036] If necessary, the above-mentioned molded product may be 100-
Additional heat treatment can be performed at 200 ° C. for 2 to 15 hours.

[0037]

The present invention will be described below in detail with reference to examples. In Tables 2 and 3, the composition is shown by weight%.

Examples 1 to 7, Comparative Example 1 The components shown in Table 1 were blended in a powder state by a mixer at the composition ratios shown in Tables 2 and 3. This is barrel temperature 90
The mixture was melt-kneaded using a twin-screw extruder at ℃, extruded in a molten state into a gut shape, and cut with a cutter. The weight of the pellets shown in Tables 2 and 3 was obtained by adjusting the speed of the cutter.

The weight of the pellets was determined by measuring the weight of 100 pellets and determining the distribution.

The time required for the pellet to reach 1.2 times the minimum viscosity η when the pellet is at 175 ° C.
During the time in the range of × 1.2, the test temperature was set at 175 ° C., the nozzle diameter / length was 0.5 / 1.0 mm, and the load was 10 kg, and the test was performed with a Koka type flow tester (manufactured by Shimadzu Corporation). The pellet was supplied in an amount of 2.5 g and measured and determined.

The weight of the supplied pellets was measured using a vibrating feeder set to measure 5 g. This test was performed 10 times, and the distribution was obtained.

In the measurement of voids, a semiconductor device was obtained by sealing and molding a semiconductor element at 175 ° C. × 2 minutes using the pellets by a low pressure transfer molding method. 40-pin DIP device (outer size: 13.5 x 51.7 x 3.8m)
m) were molded, and the cross section was observed with an ultrasonic flaw detector, the number of voids having a diameter of 0.3 mm or more was measured, and the average per package was obtained.

Example 8 In the same manner as in Examples 1 to 7, the raw materials after blending were melt-kneaded, and the discharged resin was cooled and pulverized. The obtained pulverized product was sieved to obtain pellets with a mesh opening of 1.75 mm and a pass of 1.0 mm. The evaluation was performed in the same manner as in Examples 1 to 7.

Example 9 After melting and kneading the raw materials in the same manner as in Examples 1 to 7, the discharged resin was cut by a hot cut method to obtain pellets having the weight shown in Table 3. The evaluation was performed in the same manner as in Examples 1 to 7.

[0045]

[Table 1]

[0046]

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[0047]

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[0048]

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[0049]

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[0050]

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[0051]

[Table 2]

[0052]

[Table 3] As can be seen from Tables 2 and 3, it can be seen that the pellets of Examples 1 to 9 are excellent in weighability and have few voids.

On the other hand, in the pellets of Comparative Example 1 in Table 3, since the weight of the pellets is large, it takes a long time to reach 1.2 times the minimum viscosity η, the weighability is poor, and there are many voids.

[0054]

According to the present invention, it is possible to provide a resin pellet for semiconductor encapsulation which is excellent in weighability and has few voids in a molded product. The semiconductor device formed from the pellets has less voids.

Claims (10)

[Claims] 1. A resin pellet for semiconductor encapsulation, wherein the weight of one particle is 0.1 to 30 mg. 2. A resin pellet for semiconductor encapsulation, wherein the weight of one particle is 3 to 30 mg. 3. It takes 15 minutes until the minimum viscosity η reaches 1.2 times for the first time immediately after being placed in an atmosphere at 175 ° C.
The resin pellet for semiconductor encapsulation according to claim 1, wherein the time is not more than seconds. 4. At 175 ° C., the minimum viscosity η to η × 1.
The resin pellet for semiconductor encapsulation according to any one of claims 1 to 3, wherein the time in the range of 2 is 4 seconds or more. 5. A phenol aralkyl resin as a curing agent,
The resin pellet for semiconductor encapsulation according to any one of claims 1 to 4, comprising at least one selected from a naphthol aralkyl resin, a terpene skeleton-containing phenol compound, and a dicyclopentadiene skeleton-containing phenol compound. 6. A semiconductor according to claim 1, wherein the resin discharged from the extruder is cooled, pulverized, and then sieved in producing the resin pellet for semiconductor encapsulation according to claim 1. A method for producing a resin pellet for sealing. 7. A resin for semiconductor encapsulation, wherein the resin pellet for semiconductor encapsulation according to any one of claims 1 to 5 is ejected in a gut shape from an extruder and then cut. Method for producing pellets. 8. A semiconductor sealing resin pellet according to claim 1, wherein the resin discharged from the extruder is cut by a hot cut method in producing the semiconductor sealing resin pellet according to claim 1. Method for producing resin pellets. 9. A semiconductor device in which a semiconductor element is sealed using the resin pellet for semiconductor sealing according to claim 1. 10. A semiconductor device in which a semiconductor element is sealed using a resin pellet for semiconductor sealing manufactured by the manufacturing method according to any one of claims 6 to 8.