JP2000271929A - Manufacture of granular sealing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain granular sealing material, with which the clogging of a piping such as a hopper bridge or the like can be suppressed, and execute a continuous treatment for suppressing the clogging of the piping. SOLUTION: Grinds are produced by kneading and grinding a resin component and an inorganic filler. The grinds are continuously charged in a treatment vessel 1, within which air flow circulates. The grinds treated in the treatment vessel are continuously taken out. The grinds of sealing material are processed into spherical shapes. The smooth outer shape of a granular sealing material is realized, resulting in suppressing the catching of the granular sealing materials by each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a granular sealing material for sealing a semiconductor device or the like by transfer molding or the like.

[0002]

2. Description of the Related Art As a method of sealing a semiconductor device or the like, a method of sealing by transfer molding using a sealing material such as an epoxy resin is widely used. As a sealing material used in this transfer molding, a thermosetting resin such as an epoxy resin, a curing agent, an inorganic filler, and the like are blended, and then kneaded while being heated with a roll or an extruder, and the kneaded material is formed into a sheet. After being cooled and pulverized after cooling, the kneaded material is extruded linearly and cut while cooling to form a pulverized material of the sealing material, and after measuring the predetermined weight or volume of the pulverized material, a cylindrical shape In general, a tablet-shaped sealing material which is inserted into a perforated mold and pressurized to form a column while removing air therein to produce a cylinder is used.

When performing transfer molding,
The tablet-shaped sealing material is charged into a pot provided in a mold attached to a transfer molding machine, heated and melted, then pressurized with a plunger, and passed through a runner and a gate provided in the mold. Then, a sealing material is sent to a resin molding cavity in which a semiconductor element and the like are arranged, and the sealing material is cured by heating and sealing is performed.

In order to improve productivity, a runner or the like is formed so as to send a sealing material from one pot to a plurality of cavities, and a portion to be a plurality of semiconductor devices is sealed by one sealing. Conventionally, a method called a one-pot method has been generally performed.

In recent years, in order to improve the reliability of semiconductor devices,
By forming a plurality of pots side by side, the number of cavities connected to one pot is reduced, and a method called a multi-pot method in which the length of a runner through which a molten sealing material is sent is shortened is being studied. . In the case of this multi-pot method, since the length of the runner to which the molten sealing material is sent can be designed to be short, it is possible to stably seal even a high-viscosity sealing material, and a semiconductor device having a stable quality. And it is increasing.

However, a tablet-shaped sealing material used for sealing in a multi-pot method is smaller in size than a conventional one-pot method, and it is difficult to seal the same number of semiconductor devices. It is necessary to increase the number of sealing materials, and there is a problem that the price of the sealing material to be used increases.

[0007] For this reason, a method of using a pulverized material of the sealing material, measuring a predetermined amount, charging the measured amount into a pot, and sealing without using a tablet-shaped sealing material has been studied. But,
Attempts to load a pot using a pulverized sealing material may cause clogging of a pipe such as a hopper bridge, which may cause a variation in measurement, resulting in a defective semiconductor device obtained by sealing.

In Japanese Patent Application Laid-Open No. H10-74779, the surface of a pulverized product obtained by kneading a resin component and an inorganic filler and then pulverizing is heated and melted in a fluidized bed.
By granulating in a substantially non-pressurized state, the fine powder in the pulverized material is taken into another pulverized material to increase the size and reduce the amount of the fine powder. There has been disclosed a technique for preventing a large lump or fine powder from being mixed, and for suppressing clogging of a pipe or the like due to these being caught.

However, in the prior art as described above,
A granular sealing material that does not easily cause pipe clogging can be obtained,
Batch processing in which the pulverized material is put into a processing container such as a mixer or a dryer and processed to obtain a granular sealing material, and then the granular sealing material in the processing container is replaced with an unprocessed pulverized material and the processing is performed again. Therefore, it is difficult to automate the processing and the processing efficiency is low.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a granular sealing material capable of suppressing clogging of a pipe such as a hopper bridge, and a method of suppressing the clogging of the pipe. It is an object of the present invention to provide a method for producing a granular sealing material in which a process for the above can be performed by a continuous process.

[0011]

SUMMARY OF THE INVENTION According to the present invention, a hopper bridge is formed by treating a pulverized material of a sealing material into a spherical shape so as to smoothen the outer shape of the granular sealing material and to prevent the granular sealing material from being caught by each other. The above problem is solved by suppressing the clogging of the pipes and the like and performing the spheroidizing process by a continuous process.

That is, in the method for producing a granular sealing material according to claim 1 of the present invention, a resin component and an inorganic filler are kneaded, and then pulverized to generate a pulverized product. The method is characterized in that the pulverized material processed in the processing container 1 is continuously taken out while being continuously charged into the rotating processing container 1.

According to a second aspect of the present invention, there is provided a method for producing a granular sealing material, wherein air is supplied into the processing vessel 1 at an injection pressure of 1 to 5 kg / cm ² in addition to the first aspect. Thus, an airflow swirling in the processing container 1 is generated.

According to a third aspect of the present invention, there is provided a method for producing a granular sealing material, comprising the steps of:
The processing container 1 in which a is formed of ceramic is used.

According to a fourth aspect of the present invention, there is provided a method for producing a granular sealing material, wherein air of 50 to 75 ° C. is supplied into the processing vessel 1 in addition to any one of the first to third aspects. Thus, an airflow swirling in the processing vessel 1 is generated.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a granular sealing material is obtained by kneading a resin component and an inorganic filler, and then subjecting the particles of the pulverized material obtained by the pulverization to a spherical treatment. .

The resin component essentially contains a thermosetting resin, and if necessary, a curing agent, a curing accelerator, a silane coupling agent, a release agent, a coloring agent, a low-stressing agent for the thermosetting resin. , A surfactant and a flame retardant.
Note that a thermosetting resin having a low self-curing property, such as an epoxy resin, must also contain a curing agent for curing the resin.

Examples of the thermosetting resin include an epoxy resin, a polyimide resin, a phenol resin, a silicone resin, and an unsaturated polyester resin. In the case of a resin component using an epoxy resin, the electric properties and the price are well balanced. preferable. The epoxy resin is not particularly limited, for example, orthocresol novolak type epoxy resin, bisphenol A type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin,
Examples thereof include a linear aliphatic epoxy resin, an alicyclic epoxy resin, and a heterocyclic epoxy resin. These may be used alone or in combination of two or more.

Examples of the curing agent contained in the epoxy resin-based resin component include phenol novolak resins and their derivatives, cresol novolak resins and their derivatives, mono- or dihydroxynaphthalene novolak resins and their derivatives, phenols and naphthols. And p
A phenol-based curing agent such as a condensate of xylene, a copolymer of dicyclopentadiene and phenol, an amine-based curing agent, and an acid anhydride. These curing agents may be used alone or in combination of two or more. Note that the use of a phenol novolak resin is preferable because the moisture absorption of the cured resin can be reduced. The compounding amount is usually 0.1 to 10 in an equivalent ratio to the epoxy resin.
It is blended in the range.

Further, as the curing accelerator which can be contained in the epoxy resin-based resin component, for example,
8-diaza-bicyclo (5,4,0) undecene-7,
Tertiary amine compounds such as triethylenediamine and benzyldimethylamine; imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole and 2-phenyl-4-methylimidazole; triphenylphosphine and tributyl Organic phosphine compounds such as phosphine are exemplified.

Examples of the silane coupling agent that can be contained in the resin component include epoxy silanes such as γ-glycidoxypropyltrimethoxysilane and aminosilanes such as N-phenyl-γ-aminopropyltrimethoxysilane. Is mentioned.

Examples of the release agent that can be contained in the resin component include fatty acids such as stearic acid, montanic acid, palmitic acid, oleic acid and linoleic acid, and calcium, magnesium, aluminum and zinc salts of the fatty acids. Salts such as salts, amides and phosphates of fatty acids thereof, polyethylene, bisamide, carboxyl group-containing polyolefin, and natural carnauba. When a release agent is contained in the epoxy resin-based resin component, even when an epoxy resin having high adhesion to a semiconductor element or a lead frame to be encapsulated is used, a resin cured product may be obtained during transfer molding. It is preferable because workability is improved because of excellent releasability between the mold and a plunger or a mold.

The coloring agent which can be contained in the resin component includes, for example, carbon black, titanium oxide and the like. Examples of the low-stress agent that can be contained in the resin component include silicone gel, silicone rubber, and silicone oil. Also,
Examples of surfactants that can be contained in the resin component include polyethylene glycol fatty acid esters, sorbitan fatty acid esters, and fatty acid monoglycerides. Further, as a flame retardant that can be contained in the resin component, for example, antimony trioxide, a halogen compound,
Phosphorus compounds and the like.

Two or more of these curing accelerators, silane coupling agents, release agents, coloring agents, low stress agents, surfactants, and flame retardants can be used in combination.

The inorganic filler used in the present invention is not particularly limited. For example, crystalline silica, fused silica, alumina, magnesia, titanium oxide, calcium carbonate, magnesium carbonate, silicon nitride, talc, calcium silicate And the like. The inorganic filler may be used alone or in combination of two or more. In addition, it is preferable to use silica such as crystalline silica or fused silica as the inorganic filler because the coefficient of linear expansion of the cured resin becomes small and approaches the coefficient of linear expansion of the semiconductor element. In addition, when the inorganic filler is contained in an amount of 60 to 95 parts by weight based on 100 parts by weight of the total of the resin component and the inorganic filler, the amount of moisture absorption of the cured resin is reduced, and the moisture absorption solder heat resistance is preferably excellent. In addition,
Inorganic filler used in the present invention, the granular sealing material obtained in the present invention, when sealing the resin using a mold, so as not to clog the molding die gate, and the sealing target In order not to damage the resulting semiconductor chip or the like, it is preferable to use one having a particle size of 0.5 to 50 μm.

In producing the granular sealing material, the above-mentioned resin component and inorganic filler are blended, kneaded, and then pulverized to produce a pulverized material. Conditions for the kneading and pulverization are not particularly limited.For example, after preliminarily mixing a resin component and an inorganic filler with a Henschel mixer or the like, the degree to which the resin component is softened by a hot roll, a twin-screw kneader, an extruder, or the like. Is kneaded while heating. The kneading time is such that the hardening of the resin component does not proceed so much and that the resin component and the inorganic filler are well blended. Then, while cooling, the kneaded material is stretched into a sheet, or after the kneaded material is extruded in a linear shape, pulverized using a rotary cutter, a roller mill, a hammer mill, or the like, and more preferably a 10- to 42-mesh sieve. After classification, a pulverized product having a particle size of 0.35 to 1.68 mm is produced.

The pulverized material thus obtained is continuously charged into the processing vessel 1 in which the air flow is swirling, and the pulverized material processed in the processing vessel 1 is continuously taken out. Thereby, the particles of the pulverized material are caused to collide with each other in the processing container 1 so that the corners of the particles of the pulverized material are dropped to form a sphere.

FIG. 1 shows a processing apparatus having a processing vessel 1.
The following can be used. This processing container 1 is formed in a hollow disk shape. At a substantially central portion of the bottom of the processing container 1, there is provided an outlet 1 c communicating the processing container 1 and the product discharge pipe 7. This product discharge pipe 7 is used for the processing container 1
Is extended downward from the lower part. A substantially central portion of the inner upper surface of the processing container 1 is formed as a protruding portion 1b protruding downward toward the discharge port 1c.
The gap between b and the inner periphery of the discharge port 1c is a passage through which the processed pulverized material is sent from the processing container 1 to the product discharge pipe 7. In addition, a supply port 1d is provided in an upper part of the processing container 1,
One end of a supply pipe 4b for supplying unprocessed pulverized material into the processing container 1 is connected to the supply port 1d by communicating with one end. At the other end of the supply pipe 4b, there is provided a hopper 3 to which untreated pulverized material is supplied, and at the lower part of the hopper 3, the untreated pulverized substance in the hopper 3 is processed through the supply pipe 4b into the processing vessel 1. There is provided a supply air nozzle 4a for injecting an air flow for sending the air into the inside. A plurality of air nozzles 2 for jetting air for generating an air flow in the processing container 1 are provided on the outer circumference of the processing container 1 over the entire outer circumference. The air nozzle 2 is provided so that its jetting direction is shifted from the center direction of the processing container 1 by a certain angle in the horizontal direction. Therefore, by jetting air from the air nozzle 2 into the processing container 1, A swirling airflow is generated inside. An air communication pipe 5 connected to an air supply source (not shown) such as an air pump installed outside is provided in a donut shape below the processing container 1 so as to surround the product discharge pipe 7. One end of a plurality of air supply pipes 6 is connected to the air communication pipe 5, and the other end of the plurality of air supply pipes 6 is connected to the air nozzle 2 for air flow generation and the supply air nozzle 4 a. I have. Here, the illustration of the air supply pipe connecting the supply air nozzle 4a and the air communication pipe 5 is omitted in FIG. That is, air supplied from an external air supply source is sent to a plurality of air supply pipes 6 via an air communication pipe 5 and is ejected from an air nozzle 2 for air flow generation and an air nozzle 4a for supply. The air communication pipe 5 serves as a common passage for air jetted from the air nozzle 2 for generating air flow and the air nozzle 4a for supply.

The inner wall 1a of the processing vessel 1 is made of alumina,
It is preferable to use a ceramic such as silicon nitride. The pulverized product containing the inorganic filler may collide with the inner wall 1a of the processing container 1 while moving at a high speed in the processing container 1 and wear the inside of the processing container 1. However, the inner wall 1a is made of ceramic. When it is formed, abrasion of the processing container 1 due to impact from the pulverized material can be suppressed.

When processing the pulverized material in the processing container 1 of such a processing apparatus, the pulverized material is supplied into the hopper 3 and, on the other hand, air is jetted from an air nozzle 2 for generating an air flow to process the pulverized material. An airflow that swirls inside the processing container 1 is generated in the container 1. Here, as conceptually shown in FIG. 2A, an air flow 10 generated by air 9 injected from a plurality of air nozzles 2 provided on the outer periphery of the processing container 1.
Is directed toward the discharge port 1c substantially at the center of the bottom surface of the processing container 1 while rotating inside the processing container 1.

In this state, air is injected from the supply air nozzle 4a, and the pulverized material in the hopper 3 is continuously supplied into the processing container 1 from the supply port 1d. As conceptually shown in FIGS. 2A and 2B, the pulverized material 11 supplied into the processing container 1 is swirled in the processing container 1 due to the airflow 10 in the processing container 1, and the discharge port 1c is rotated. At this time, the pulverized material 11 has a spherical shape due to the interaction due to the collision of the particles of the pulverized material 11 with the particle surface angle falling and the spherical shape of the pulverized material 11 being substantially maintained in the particle size or in a finely divided state. Become The pulverized material 11 thus spherical is supplied from the outlet 1c to the product discharge pipe 7.
Then, the crushed material 11 is discharged to the outside of the processing apparatus and collected, and the spherical pulverized material 11 is obtained as a granular sealing material.

The air injection pressure from the air nozzle 2 for where airflow generating is preferably in a 1-5 kg / cm ^2, the interaction between ground product in process and less than 1 kg / cm ² When the particle size exceeds 5 kg / cm ² , the pulverized material breaks down during processing and conversely forms a corner of the pulverized material. May be difficult.

In the granular sealing material thus obtained, the external shape of the particles becomes smooth, and the particles of the granular sealing material are prevented from being caught by each other. In performing resin sealing of a semiconductor device or the like, it is possible to suppress clogging of a pipe such as a hopper bridge and improve work efficiency. Further, the process for suppressing such pipe clogging is performed by a continuous process, thereby facilitating automation of the process, improving the process efficiency, and improving the production efficiency of the granular sealing material.

Here, a heater 8 is provided in an air supply pipe 6 connected to the air nozzle 2 for generating air flow, and air supplied from the air nozzle 2 for generating air flow is supplied to the heater 8.
When heated in the range of 50 to 75 ° C. in the processing container 1, the surface of the pulverized material is melted in the processing container 1, and the surface of the obtained granular sealing material can be further smoothed. In addition, the fine powder generated by the spheroidization of the granular sealing material adheres to the melted surface layer of the particles of the granular sealing material and is integrated with the particles, and the surface is smoothed. Since the chipping of the fine powder is suppressed from the granular sealing material,
Generation of fine particles when transferring the granular sealing material can be suppressed. Therefore, the obtained granular sealing material is transported more smoothly in the pipe, and the clogging of the pipe such as the hopper bridge can be further suppressed.

[0035]

The present invention will be described below in detail with reference to examples.

(Production of pulverized sealing material) A mixture containing the following components was dry-blended with a Henschel mixer, melt-kneaded at 95 ° C with a mixing roll, cooled, and then sealed with an epoxy resin. The material was obtained. -Cresol novolak type epoxy resin [manufactured by Nippon Kayaku Co., Ltd., product number: EOCN1020] 118 g-Brominated epoxy resin [manufactured by Nippon Kayaku Co., Ltd., product number:
BREN-S] 14 g ・ Novolak phenol resin [manufactured by Arakawa Chemical Co., Ltd., product number: Tanomar 759] 68 g ・ Triphenylphosphine 1.5 g ・ Carnauba wax 3 g ・ Antimony trioxide 21 g ・ Carbon black 2.5 g ・ Fused silica powder 772 g After crushing the epoxy resin sealing material with a crusher, 10
Classify with a sieve of mesh ~ 42 mesh, particle size 0.3
A crushed product of the sealing material having a size of 5 to 1.68 mm was obtained.

(Examples 1 to 7) Using a processing apparatus as shown in FIG. 1 [jet pulverizer manufactured by Nippon Pneumatic Co., Ltd., product number PJM200SP], the pulverized material was processed under the conditions shown in Table 1. A granular sealing material was obtained. Here, in the column of the material in the table, the product number of the resin composition used to prepare the pulverized material, the total amount of the pulverized material subjected to the treatment in the column of the supply amount, and the pulverization in the column of the supply time. Processing container 1 for all things
In the column of the supply speed, the time required to supply the pulverized material into the processing container 1 is shown, and in the column of the supply pressure, the ejection of the air ejected from the air nozzle 2 for generating the air flow is shown. The column of the pressure and the temperature of the air jetted from the air nozzle 2 for generating the airflow are described in the columns of the supply air temperature.

(Comparative Example 1) A pulverized product not subjected to a spheroidizing treatment was used as a granular sealing material as it was.

(Evaluation Test) Measurement of Recovered Amount In Examples 1 to 7, the recovered amounts of the granular sealing material recovered through the product discharge pipe 7 and the pulverized material remaining in the processing container 1 were measured.

-Yield measurement-In Examples 1 to 7, the treated granular sealing material recovered through the product discharge pipe 7 was sieved with a 42-mesh sieve to remove fine powder, and the remaining granular material was not passed through the sieve. The proportion of the sealing material was measured.

-Measurement of Smoothness- For Examples 1 to 7 and Comparative Examples 1 and 2, the apparent density of the obtained granular encapsulating material was measured. It was evaluated as having been dropped and smoothed. The evaluation criteria are shown below. ◎: 1.016 g / ml or more in apparent density ○: 0.980 g / ml or more in apparent density
×: less than 016 g / milliliter ×: apparent density: less than 0.980 g / milliliter —Evaluation of glossiness— For Examples 1 to 7 and Comparative Examples 1 and 2, the obtained granular encapsulating material was visually observed, and The presence or absence of gloss on the particle surface was evaluated.

Table 1 shows the results.

[0043]

[Table 1]

As is clear from Table 1, in each embodiment,
It was confirmed that the particle surface of the granular sealing material was smoother than in the case of Comparative Example 1 and was spherical. Further, in Examples 6 and 7, the particle surface of the granular sealing material had a gloss, and the smoothness was improved and the yield was higher than that of Example 5 treated under the same conditions as in Examples 6 and 7, except for the supply air temperature. It was confirmed that the ratio was improved and the generation amount of the fine powder was reduced, and it was confirmed that the generation of the fine powder was suppressed by melting the particle surface.

[0045]

According to the method for producing a granular sealing material according to the first aspect of the present invention, a resin component and an inorganic filler are kneaded, and then pulverized to produce a pulverized product. Is continuously introduced into the rotating processing vessel, and the pulverized material processed in the processing vessel is continuously taken out. The granular sealing material thus obtained has a smooth outer shape. Therefore, the clogging between the granular sealing materials is suppressed, and therefore, when resin sealing of the semiconductor device is performed using the granular sealing material, the clogging of pipes such as a hopper bridge is suppressed to reduce the work efficiency. It can be improved. Further, the process for suppressing such pipe clogging is performed by a continuous process, thereby facilitating automation of the process, improving the process efficiency, and improving the production efficiency of the granular sealing material.

According to a second aspect of the present invention, there is provided a method for producing a granular sealing material, wherein air is supplied into the processing vessel at an injection pressure of 1 to 5 kg / cm ² in addition to the first aspect. This generates an airflow that swirls in the processing vessel, and can efficiently perform the spheroidization of the granular sealing material, and can also prevent the crushed material from being crushed during the processing, and the spheroidized crushed material can be formed. It can be achieved sufficiently.

According to a third aspect of the present invention, there is provided a method for producing a granular sealing material, wherein a processing container having an inner wall formed of ceramic is used in addition to the first or second aspect.
It is possible to suppress abrasion of the processing container due to impact from a crushed material moving at a high speed in the processing container.

According to a fourth aspect of the present invention, there is provided a method for producing a granular sealing material, comprising supplying air at 50 to 75 ° C. into a processing container in addition to any one of the first to third aspects. This is to generate an airflow that swirls in the processing vessel, melts the surface of the granular sealing material during processing, further smoothes the surface of the obtained granular sealing material, and generates fine powder from the granular sealing material. The generation can be suppressed, and the clogging of a pipe such as a hopper bridge can be further suppressed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a processing apparatus that can be used in the present invention.

FIGS. 2A and 2B are conceptual diagrams illustrating an air flow and a flow of a pulverized material in a processing container, where FIG. 2A is a plan view and FIG. 2B is a perspective view.

[Explanation of symbols]

 1 Processing vessel 1a Inner wall

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F201 AB11 AB16 AH37 AJ06 AJ09 AR02 BA02 BC01 BC12 BC17 BC19 BL01 BL05 BL21 BL25 BQ02 BQ45 4M109 AA01 BA01 BA03 CA21 EA01 EA02 EA07 EA10 EB02 EB03 EB04 EB06 EB07 EB08 EB07 EB08 AA01 BA01 BA03 CA21 DE02 DE04

Claims (4)

[Claims] 1. After kneading a resin component and an inorganic filler,
Pulverizing to produce a pulverized product, continuously pour the pulverized product into a processing vessel in which an air current is swirling, and continuously take out the pulverized product processed in the processing container. Of producing a granular sealing material. 2. The granular sealing according to claim 1, wherein air is supplied into the processing vessel at an injection pressure of 1 to 5 kg / cm ² to generate an airflow circling in the processing vessel. Material manufacturing method. 3. The method for producing a granular sealing material according to claim 1, wherein a processing container having an inner wall formed of ceramic is used. 4. The granular sealing material according to claim 1, wherein an airflow swirling in the processing container is generated by supplying air at 50 to 75 ° C. into the processing container. Manufacturing method.