JP2694293B2 - High compression molding resin tablet molding method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a molding method of a resin tablet used for sealing and molding electronic parts such as ICs, diodes and capacitors.

[Conventional technology]

2. Description of the Related Art A transfer resin molding (molding) method has heretofore been adopted for sealing and molding an electronic component with a thermoplastic or thermosetting resin material.

In an apparatus for carrying out this resin molding method, for example, as shown in FIG. 4, an upper mold A, a lower mold B opposed to the upper mold A, and a lower mold B are arranged. A pot C for supplying the resin material, a plunger D for pressurizing the resin material to be fitted into the pot C, and an electronic component provided opposite to the PL (parting line) surface of both molds (A and B). Molten resin material consisting of a cavity E for resin encapsulation molding and a cull part (F ₁ ), a runner part (F ₂ ), and a gate part (F ₃ ) arranged between the pot C and the upper mold cavity E. The transfer passage F and the like are provided. The resin encapsulation molding of the electronic component by this apparatus is performed as follows.

First, when both molds (A and B) are opened, the electronic component G
The lead frame H on which is mounted is fitted at a predetermined position of the setting groove portion I formed on the PL surface of the lower mold B, and the resin material R is supplied into the pot C, and the lower mold B is moved upward in this state. Then, both molds (A and B) are clamped. At this time,
The resin material R in the pot C is heated and melted by the heater J provided in both molds (A and B). Therefore, when the resin material R is pressurized by the plunger D, the molten resin material is transferred from the pot C to the passage. It will be injected under pressure into both cavities E through F and filled. Next, after the required carry time, the lower mold B is moved downward to open the molds (A and B) again, and the inside of the transfer passage F and both cavities E are opened.
The resin moldings (R ₁ and R ₂ ) inside are released from both upper and lower ejector pins K. Next, the unnecessary portion R _{1 of the} resin molded body
By removing unnecessary parts of the lead frame H, it is possible to obtain a product in which the electronic component G is encapsulated and molded in the resin molding R ₂ corresponding to the shapes of the cavities E.

[Problems to be solved by the invention]

By the way, as the above-mentioned resin material R, a tablet in which a certain amount of resin powder is compressed and formed into a shaft shape having a required length has been used.

Conventional resin tablets are required to have a shape-retaining property such that they are not easily damaged during handling. As a means for imparting this shape-retaining property, for example, a predetermined amount is stored in a required accommodation hole (cylinder). The resin powder is stored and the resin powder is pressure-molded by a piston.

In the conventional resin tablet pressure-molded by this shape-retaining means, usually about 77-80% (density)
Therefore, the conventional object described above can be achieved.

However, since a large number of fine pores are present inside the above-mentioned resin tablet, the resin tablet usually contains about 10 to 20% by volume of air. Also, this type of resin tablet easily absorbs moisture,
Therefore, it may contain water after compression molding.

From the above, the conventional resin tablet has the following problems in resin molding.

That is, when the above-mentioned resin tablet containing air and water is supplied into the pot C and heated and melted, a large amount of air is mixed into the molten resin material. Since this mixed air will form voids on the surface or inside of the resin-sealed molded body (R ₂ ), it may impair the moisture resistance and mechanical strength of the product or its appearance. It is said to be a factor that causes harmful effects. Furthermore, the resin-sealed molded body (R ₂ ) described above tends to be molded with a smaller size and wall thickness, and the void is a defective portion composed of bubbles generated from the mixed air. Therefore, there is a serious problem that impairing the moisture resistance and the mechanical strength described above significantly deteriorates the quality and reliability of this type of product.

In the compression molding experiment of the resin powder by the above-mentioned conventional shape-retaining means, the compression density could be increased to about 96%.

However, particularly in the case of a resin material in which about 70% (weight ratio) of silica is mixed as a filler in the resin powder, the degree of wear of the accommodating hole (cylinder) and piston due to this silica is extremely large, Therefore, in forming a high-density resin tablet whose compressed density is always about 94%, there are many problems in terms of quality equalization, productivity, and overall economy. Therefore, in consideration of these points, in the conventional shape-retaining means, the limit is set to about 93 to 94%, preferably about 90%. After all, the compression density of resin powder that can be molded and produced is about 77
It was about 94%.

Also, by supplying resin into the shape memory alloy molding die,
By heating the mold at a shape memory temperature set to a temperature lower than the melting point of the resin, the resin in the mold is compression-molded, and then the mold is cooled to a predetermined temperature. In this way, a molding method has been proposed in which the compression molding resin in the mold is taken out.
No. 196006). Therefore, according to this method, the resin can be compression-molded by heating and cooling the mold to a predetermined temperature. However, there is a problem that productivity is low when the above-mentioned means for changing the shape of the mold by heating and cooling the mold is adopted.

An object of the present invention is to reliably eliminate the above-mentioned conventional problems by providing a molding method capable of efficiently producing a high compression molded resin tablet from which internal air has been removed. Is.

The invention of this application is based on the method and apparatus of resin encapsulation molding for electronic parts disclosed in the original patent application (Japanese Patent Application No. 63-326559) dated December 24, 1988. And a method for molding a high compression molded resin tablet used in the apparatus.

[Means for solving the problem]

A method for molding a high compression molded resin tablet according to the present invention includes accommodating a predetermined amount of resin powder in an elastic mold for high compression molding including an opening / closing lid and a molding rubber mold, and deforming the molding rubber mold. By applying a uniform high compressive force to the resin powder in the elastic mold, the resin tablet from which the air inside the pressure-molded body is removed is molded.

Further, the molding method of the high compression molded resin tablet according to the present invention is to deform the molding rubber mold described above to apply a high compression force by the uniform fluid pressure of 1000 kgf / cm ² or more to the resin powder in the elastic mold. It is a feature.

(Operation)

ADVANTAGE OF THE INVENTION According to this invention, the high compression molding resin tablet from which the internal air was removed can be efficiently and reliably molded.

Furthermore, by using the high compression molded resin tablet, it is possible to reliably prevent a large amount of air from being mixed into the molten resin material during resin encapsulation molding of the electronic component. It is possible to efficiently and surely prevent the formation of voids inside or on the surface of the molded body to be sealed.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 shows an example of each step of resin encapsulation molding of electronic parts, FIG. 2 shows an example of the constitution of a molding apparatus for a high compression molded resin tablet used in the present invention, and FIG. Each example of the structure of the mold for resin sealing molding of electronic parts is shown.

Further, (1) and (2) of FIG. 1 show a molding process of the high compression molded resin tablet according to the method of the present invention, and (3) and (4) of FIG. In the transfer and supply process, the electronic part is shown in (5) in the figure.
The step of clamping the mold after supplying and setting it at a predetermined position on the PL surface is also shown in FIGS. 6 (7) and 6 (7). The resin encapsulation molding process of the parts is shown respectively.

In the molding process of the high compression molding resin tablet shown in FIGS. 1 (1) and (2), for example, a predetermined amount of thermosetting resin powder such as epoxy resin is stored in an elastic mold for high compression molding, and By applying a required high compression force to the resin powder inside through the elastic mold, a high density, ie, high compression molded resin tablet from which air has been removed is molded.

Molding apparatus of a high compression molding resin tablet used in order to carry out this process, FIG. 1 (1) (2) and as shown in FIG. 2, 2 _2-closing lid 2 _1-molded rubber mold an elastic type 2 for compression molding comprising a pressurized rubber mold 2 _3-pressure cylinder 2 _4, etc., through the elastic type 2, the required high compression resin powder 1 of a predetermined amount that is housed inside the elastic mold And a high compression molding means for applying a force.

In order to mold a high compression molded resin tablet using the molding device, first, a predetermined amount of resin powder 1 is placed in the elastic mold 2.
A high compression molding means for appropriately supplying and accommodating it inside, and then applying a high compression force to the resin powder 1 inside through the elastic mold ^{2 by} a uniform fluid pressure 3 of, for example, 1000 kgf / cm ² or more ( (Not shown) may be compression molded into a desired tablet shape. At this time, compression molded resin tablet 4
_{No. 1} has no pores formed inside. That is, it is formed as a highly compressed molded body in an extremely high density state in which the air inside is removed. It should be noted that the extremely high density state in which the air inside is removed is, for example, about 95-
It means 100% high density. That is, if it is within the range of about 95 to 100%, even if air is contained in the pressure-molded body, the amount thereof is extremely small, so this should be kept during resin encapsulation molding of electronic parts. Because it can be ignored.

Further, in the step of transferring and supplying the high compression molded resin tablet shown in FIGS. 3 (4) and (4), the high compression molded resin tablet housed in the elastic mold for high compression molding is sucked and adsorbed and taken out. Is transferred to the mold pot side of the resin encapsulation molding apparatus and supplied into the pot.
That is, high compression molding resin tablet 4 _1, which is by and housed molded by the above-described high compression within molding elastic die 2, together with the sucking suction by the suction suction means 5 ₁ at the transfer feed mechanism 5, in this state, it is intended to put in the pot by transferring the resin tablet 4 ₁ in a mold pot side of the resin-seal-molding apparatus.

In the mold clamping step shown in FIG. 5 (5), a lead frame having electronic components mounted is fitted and set at a predetermined position on the lower mold PL surface of the mold of the resin encapsulation molding apparatus, and The upper and lower dies are clamped together by moving up.

In addition, in the resin encapsulation molding step of electronic parts shown in FIGS. 6 (7) and 7 (7), the resin material supplied into the mold pot is heated and melted, and the molten resin material is passed through the transfer passage. It is injected under pressure into the cavity.

Further, the above-mentioned mold is a resin sealing molding device, for example,
So-called, with a required number of pots and plungers,
The multi-plunger mold device 7 is installed and used.

In this multi-plunger molding apparatus, as shown in FIG. 3, an upper mold 8 on the fixed side, a lower mold 9 on the movable side opposed to the upper mold 8, and a lower mold 9 were arranged. A plurality of required pots 10 (arranged in the figure at a predetermined distance in the front-rear direction), a plunger 11 that is constantly fitted in each pot 10, and upper and lower molds (8. 9) Cull portion 13 ₁ , runner portion 13 ₂ disposed between the resin molding cavities 12 opposed to the PL surface and each pot 10 and a required number of cavities 12 disposed at predetermined positions around the pots 10. flume 13 and the like of the molten resin material consisting of gate 13 ₃ is provided. Also,
In the above-mentioned transfer passage 13 part and both cavity 12 parts,
An ejector pin 16 for releasing the resin molded bodies 14 and 15 solidified and molded in the transfer passage 13 and both cavities 12 is fitted, and further, on the PL surface of the lower mold 9,
A groove portion 19 for fitting and setting the lead frame 18 on which the electronic component 17 is mounted is formed.

In addition, a space portion serving as a resin material supply portion or a molten resin material filling portion configured when the upper and lower molds (8, 9) are clamped, that is, the above-mentioned pot 10 portion, transfer passage 13 portion, and An intake passage 21 composed of an intake hole 21 ₁ , an intake hose 21 _{2 and the} like is provided in communication between both cavities 12 and a required vacuum source 20 side. Therefore, both upper and lower types (8, 9)
When the mold is clamped, by operating the vacuum source 20, it is possible to perform a vacuum process for forcibly sucking and removing the residual accumulated air in these space parts (10, 13, 12) to the outside. Has been done. That is, high compression molding resin tablet 4 _first supply process to the above-described mold pot, and, after the setting process of the electronic component 17 to the mold PL surface has been performed, the both types of (8.9) A mold clamping process and a vacuum process can be performed.

The molding apparatus for the high compression molded resin tablet used in the present invention and each apparatus for performing the other steps shown in FIG. 1 are integrally provided in the vicinity of the resin sealing molding apparatus described above, respectively. Alternatively, it can be detachably arranged.

The resin encapsulation molding of the electronic component using the resin encapsulation molding apparatus is performed in the same manner as the conventional one described above. That is, the resin tablet 4 ₁ mold pot 10 upper and lower mold sections (8
- 9) to be heated and melted by the heater 22 of, when pressed by the molten resin material 4 ₂ plunger 11, the molten resin material is injected under pressure into the respective cavity 12 through transfer path 13 The electronic parts 17 on the lead frame 18 set in the respective cavities can be respectively resin-sealed and molded.

However, resin tablet 4 ₁ described above, as described above, since the inside of the air is highly compressed molding is removed, and heating and melting of the resin tablets, the molten resin material 4 _second pressure transfer, and can be at the time of molding resin to seal action called its pressure injection into the cavity 12, air is reliably prevented from being mixed into the molten resin material 4 _2. Therefore, it is possible to prevent the conventional adverse effect that a void is formed inside or on the surface of the resin molded body that seals the electronic component with the resin due to the large amount of air mixed in the molten resin material. It is a thing.

Further, when the vacuum process described above is used in combination, it is possible to maintain a vacuum state in the space portion serving as the resin material supply portion configured when the upper and lower molds are clamped, or the molten resin material filling portion, Since air in the space, or air and water can be removed, it is possible to more reliably prevent them from being mixed in the molten resin material.

It should be noted that the present invention is not limited to the above-described embodiments, and can be arbitrarily and appropriately changed and selected and adopted within a range not departing from the spirit of the present invention.

For example, the examples mainly described a thermosetting resin material such as an epoxy resin containing about 10% of a curing agent in the resin powder, but a resin powder not containing this curing agent, that is, It is obvious that the same can be applied to the molding method of the high compression molding resin tablet using the thermoplastic resin material.

Further, as a configuration mode of the molding method / apparatus of the high compression molded resin tablet described above, a single molding die for molding a single high compression molded resin tablet, or a plurality of required high compression molded resin tablets at the same time. Any of the methods and configurations using a plurality of molding dies for molding may be adopted. For example, a method or configuration using a single molding die for molding a single high compression molding resin tablet may be adopted corresponding to the case of using a single pot plunger molding device, or a multipot plan. It is also possible to adopt a method / structure that uses a plurality of molding dies that are configured to correspond to the arrangement positions and the number of the required plurality of pots provided in the jar molding apparatus. Further, a single molding die or a plurality of molding dies can be arbitrarily adopted irrespective of such a constitution on the molding apparatus side.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY According to the present invention, there is an excellent practical effect that highly compressed molded resin tablets in a very high density state from which internal air is removed can be produced with high efficiency.

Furthermore, when the high compression molded resin tablet molded according to the present invention is used, it is possible to efficiently and reliably prevent air from being mixed into the molten resin material during resin sealing molding of electronic parts. It is possible to prevent the conventional adverse effect that a void is formed inside or on the surface of the resin-molded resin molded product of the electronic component due to a large amount of air mixed in the molten resin material, in advance and reliably. . In addition, the conventional problems such as the moisture resistance, mechanical strength or appearance of this kind of product can be surely solved, which greatly contributes to the production of this kind of product with high reliability and high quality. It has excellent practical effects that can be achieved.

[Brief description of the drawings]

(1) to (7) of FIG. 1 are schematic explanatory views showing an example of each step of resin sealing molding of an electronic component. FIG. 2 is a partially cutaway vertical sectional view schematically showing a main part of a molding apparatus for a high compression molded resin tablet used in the present invention. FIG. 3 is a partially cutaway vertical front view schematically showing a main part of a resin sealing molding die for an electronic component. FIG. 4 is a partially cutaway vertical front view showing a mold configuration example in the transfer resin molding apparatus. [Explanation of symbols] 1 …… Resin powder 2 …… High compression molding elastic mold 2 ₁ …… Opening / closing lid 2 ₂ …… Molding rubber mold 2 ₃ …… Pressing rubber mold 2 ₄ …… High pressure cylinder 3 …… Fluid pressure 4 …… Resin tablet 4 ₁ …… Resin tablet 4 ₂ …… Melted resin material 5 …… Transfer supply mechanism 7 …… Multi-plunger mold device 8 …… Upper mold 9 …… Lower mold 10 …… Pot 13… … Plunger 12 …… Cavity 13 …… Transport passage 15 …… Resin molding 17 …… Electronic parts 18 …… Lead frame 19 …… Groove 20 …… Vacuum source 21 …… Intake passage

Claims (2)

(57) [Claims] 1. A predetermined amount of resin powder is contained in an elastic mold for high compression molding provided with an opening / closing lid and a molding rubber mold, and the molding rubber mold is deformed to become resin powder in the elastic mold. A method for molding a high compression molded resin tablet, which comprises molding a resin tablet from which air inside the pressure molded body is removed by applying a uniform high compression force. 2. The high compression molding resin according to claim 1, wherein the molding rubber mold is deformed to apply a high compression force to the resin powder in the elastic mold by a uniform fluid pressure of 1000 kgf / cm ² or more. Tablet molding method.