JPS6334271Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention relates to the improvement of a molding machine that molds a semiconductor element mounted on a lead frame in a resin-encapsulated manner. It is used in the field of resin encapsulation molding technology industry.

(Prior Art) Conventionally, molding machines for resin-encapsulating semiconductor devices have a basic structure in which a large number of molding cavities and one large pot are arranged in communication with each other via runners and gates. However, this molding machine has the drawback that the resin solidified and formed in the runner section cannot be used effectively, and the runner is relatively long, so The injection time, pressure, viscosity, etc. of the molten resin into each cavity are not uniform, and there are problems in that it is difficult to equalize the quality of the molded products. In order to solve such problems,
First, a multi-plunger type molding machine was developed, in which a plurality of cavities, pots, and plungers were provided, and the cavities and pots were communicated only through gates.
119173 etc.).

In the above-mentioned multi-plunger type molding machine, molding resin materials are charged into each pot, the materials are melted under pressure by each plunger, and the molten resin is introduced into the cavity through only the gate. It can be injected in a short time.

By the way, if the amount of resin put into each pot is uniform, there is no problem in pushing each plunger at the same time, but if there is an excess or deficiency in the amount of resin mentioned above, please adjust the pressure on each resin material. It becomes impossible to maintain the pressure constant, and therefore, differences occur in the pressure and amount of resin injected into each cavity, making it impossible to equalize the quality. Therefore, in the above-mentioned molding machine, each plunger is fitted into a cylinder, and each plunger is configured to be pushed individually using hydraulic pressure or the like.

However, for example, when hydraulic pressure is used as the pushing force for the plunger described above, the overall structure of the molding machine becomes complicated due to the provision of oil supply pipes, etc., and the overall shape becomes larger. In addition, there are problems such as an increase in the manufacturing cost of the molding machine.

(Problems to be Solved by the Invention) The present invention adopts the multi-plunger type described above, has each plunger mounted on a shaft so that it can advance and retreat independently, and applies elastic pushing force such as a spring to each plunger. By improving the pressurizing device for resin materials by configuring them to be added separately,
The purpose is to simplify and downsize the overall structure and shape of a molding machine, increase its handling capacity, and reduce the manufacturing cost of the molding machine.

(Means for Solving the Problems) In order to achieve the above object, the resin encapsulation molding machine for semiconductor elements according to the present invention has an upper mold and a lower mold having a plurality of required resin material injection pots. In a resin encapsulation molding machine for semiconductor devices, which is equipped with a mold and a pressurizing device for the resin material charged into each pot, the pressurizing device fits the upper end into each pot, and also presses the base of the mold. A plunger for pressurizing a resin material whose end portions are individually fitted into the lower reciprocating body; a vertical reciprocating mechanism for the reciprocating body; a seat individually engaged with the lower end surface of each of the plungers; and an elastic pushing member that elastically pushes each of the plungers individually upward through the seat.

(Embodiment 1) Next, the present invention will be explained based on the first embodiment diagrams shown in FIGS. 1 to 4.

FIG. 1 shows the main parts of a resin encapsulation molding machine 1 for semiconductor devices, and the molding machine includes a fixed upper mold 2, a movable lower mold 3 disposed opposite to the upper mold, and a pressurizing device 4 for pressurizing resin material. It is composed of.

Further, the lower mold 3 is fixed to a lower movable platen 8 via a lower mold plate 5 and space blocks 6 and 7, and the movable platen is moved by an appropriate vertical movement mechanism (not shown). It is provided to rise when the mold is closed and to fall when the mold is opened.

Further, the lower mold 3 is provided with a plurality of pots 9...9 for inserting resin materials, and each of the pots 9 is arranged on the parting line (P/L) surface with the upper mold 2 side. One or more cavities 10...10 for resin molding are arranged close to the installation position. In addition, on the parting line (P/L) surface of the upper mold 2, at positions opposite to the positions of the respective pots 9...9 and the lower mold cavities 10...10,
Culls 11...11 and upper mold cavities 12...12 are provided, and gates 13 for pressurized injection of molten resin are provided between the culls and the upper mold cavities.
Only 13 are formed in communication. Furthermore, ejector pins 14, 1 are provided at each position of the cull 11, gate 13, and upper mold cavity 12 for extruding a resin molded product (resin-filled molded product of a semiconductor element).
5 and 16 are fitted into each other, and the proximal ends of the respective pins are respectively fixed to ejector plates 18 provided so as to be moved downward by the spring elasticity of the push-down springs 17. Furthermore, ejector pins 19 and 20 for extruding a resin molded product are fitted and arranged at each position on the lower mold 2 side corresponding to the position of each groove 13 and at each position of the lower mold cavity 10, respectively. At the same time, the base end of each pin is fixed to an ejector plate 22 which is provided to be moved downward by a push-down spring 21. In addition, both the ejector plates 18, 2
Return pins 23 and 24 are respectively fixed to 2, and the lower end surface of the upper return pin 23 is in contact with the lower mold 3 side, and the upper end surface of the lower return pin 24 is in contact with the upper mold 2 side. Further, the lower ejector plate 22 is provided so as to be moved up and down by an ejector bar 25 in the up and down movement mechanism. Further, the upper mold 2 is fixed via an upper mold plate 26 and an upper mold space block 27 to an upper fixed platen 28 fixed to a column (not shown). Further, the pressurizing device 4 for the resin material has a reciprocating body 29 disposed below the lower mold 3 so as to be able to reciprocate up and down within the space formed by the space block 7.
, a reciprocating drive mechanism 30 that reciprocates the reciprocating body up and down using power such as hydraulic pressure, and a plurality of required resin materials disposed corresponding to the positions of the respective pots 9...9 disposed on the lower mold 3. Plunger 31...3 for pressurization
1, and elastic pushing members 32...3 such as plate springs or compression coil springs that push each of the plungers separately and equally in the direction of pressurizing the resin material.
It is composed of 2. Further, each of the plungers 31 has its upper end portion 31 ₁ fitted into the pot 9, and its base end portion 31 ₂ is moved upwardly and downwardly into the upper portion of the reciprocating body 29. Furthermore, the elastic pushing member 32, which is separately installed in the reciprocating body, is engaged with the lower end surface of each plunger via a seat 33, as will be described later. There is. Note that the pushing force of each of the elastic pushing members 32 is set equally by, for example, making the spring constant of the compression coil spring constant. Furthermore, as shown in the figure, the same number of elastic pushing members 32 as the number of arranged plungers 31 may be arranged, but under the condition that the above-mentioned equal pushing force is applied to each plunger 31 separately. It may be formed integrally.

Incidentally, between the molds 2 and 3, a protruding strip 34 and an engagement groove 35 that engages with the protruding strip are provided respectively in order to properly match the molds when the molds are clamped.

In order to perform resin encapsulation molding of a semiconductor element with a molding machine having the above configuration, first, the lower mold 3 is moved downward by the vertical movement mechanism to open the mold, and each plunger in the pressurizing device 4 for the resin material is Move 31 downward. Next, with a lead frame having a semiconductor element set between the parting lines (P and L) of both molds 2 and 3, the molds are clamped and a resin material is appropriately supplied into each pot 9. Next, the resin material is heated by both molds 2 and 3, and the reciprocating body 29 and each plunger 31 are moved upward by the reciprocating drive mechanism 30 to pressurize the upper end portion ₃₁₁ . The resin is melted and injected under pressure into the cavities 10 and 12 through the gate 13, thereby molding the semiconductor element on the lead frame in the cavity to be resin-encapsulated. After this resin molding, the mold is opened again, and the ejector plate 22 and ejector pins 19, 20 are moved upward by the ejector bar 25 on the lower mold 3 side, and at the same time, the ejector plate 22 and the ejector pins 19, 20 are moved upward on the ejector bar 25 on the lower mold 3 side. By moving the Ector pins 14, 15, and 16 downward, the resin molded product is transferred to the upper mold cavity 12, the upper mold gate 13, the upper mold cull 11, and the lower mold cavity 10.
All you have to do is push it outside.

In addition, in the pressurizing action of the resin material mentioned above,
Each plunger 31 in the pressurizing device 4 is
As mentioned above, each pot 9 can be moved upward in response to the amount of resin material supplied in each pot 9, and an equal pressing force can be applied to each supplied resin material. Even if the amount of resin material supplied in each cavity is different,
Pressurized injection of molten resin material into 0.0 and 12 parts is carried out simultaneously under the same conditions. In other words, even if the amount of resin material supplied in each pot is different, it is possible to apply equal pressure to them, thereby preventing the formation of voids (air holes) in the resin molded product due to insufficient pressure, etc. This molding method is suitable for high-quality and high-efficiency production, as it is possible to reliably prevent this and improve the quality of this type of product, and also to stabilize the quality of molded products by stabilizing the injection pressure of molten resin. It is possible to provide a machine. In addition, since equal pushing force is applied to each of the above plungers by the elastic pushing member, the resin material is pressurized by the elastic pushing force of the elastic pushing member, but the pressing force is insufficient. In such a case, it is sufficient to further raise the reciprocating body 29 using the reciprocating drive mechanism 30.

Furthermore, the plunger is actually fitted with a required clearance between the base end 31 ₂ and the reciprocating body 29.

Thus, during resin molding, a difference in temperature between the upper end 31 ₁ and the base end 31 ₂ of the plunger is generated based on the mold temperature. That is, the upper end portion 31 ₁ fitted into the pot 9 becomes difficult to slide due to thermal expansion. However, even in such a case, the above-mentioned required clearance is secured because the base end 31 ₂ is at a low temperature, so the upper end 31 ₁ of the plunger may be difficult to slide during resin molding. However, the proximal end portion 31 ₂ can maintain flexibility (freely fitted state).

Plunger 31, elastic pushing member 32 and seat 33
To explain the relationship in more detail based on the drawings, the plunger 31 and the elastic pushing member 32 are configured to be separated via a seat 33. That is, as shown in FIG. 1, the seat 33 is interposed between the plunger 31 and the elastic pushing member 32. Therefore, the elastic pushing force (upward force) of the elastic pushing member 32 is applied to the plunger 31 via the seat 33. However, the elastic pushing member 32 and the seat 33 are fitted into a mounting hole formed in the reciprocating body 29, and in this state, the elastic pushing force of the elastic pushing member 32 is applied to the seat 33. has been added. Therefore, the seat 33 is normally elastically pressed against the upper end surface of the mounting hole, as shown in FIGS. 1 and 2 (the right side portion indicated by the solid line). Therefore, the elastic pushing force of the elastic pushing member 32 described above is not directly applied to the plunger 31 under normal conditions, and therefore, the elastic pushing force is not applied as a force to push the plunger 31. It is configured such that it cannot be substantially and effectively added.

In addition, as mentioned above, each plunger 31
is moved upward in accordance with the amount of resin material supplied when the resin material in each pot 9 is pressurized during resin encapsulation molding. That is, the plunger 31 is moved upward by the reciprocating drive mechanism 30, but the relationship with the reciprocating body 29 that supports the plunger 31 is as shown in FIG. 2 (left side indicated by solid line). In this case, each part is lowered in accordance with the amount of resin material supplied. The purpose of this downward movement is to pressurize the resin material in each pot 9 evenly, but such a plunger 31
When the downward movement of the plunger 31 is started, the plunger 31
The elastic pushing force of the elastic pushing member 32 described above is substantially and effectively applied to the above-described elastic pushing member 32. However, until the downward movement of the plunger 31 starts, the plunger 31
is maintained at the normal state described above. Therefore, the flexibility of each plunger base end 31 ₂ (freely fitted state)
In addition, even if there is a misalignment between the axis of the plunger 31 and the radial center of the elastic pushing member 32, the seat 33 interposed between the two can substantially and reliably absorb the misalignment. , and plunger 31
The replacement work, etc. becomes easier.

(Embodiment 2) The configuration of the pressurizing device 4 in the previous embodiment may be improved and the device may be configured as in the second embodiment (FIG. 5).

That is _, in the configuration of the second embodiment, as shown in _{FIG .}
The push-up plate 3 has its lower end individually locked.
A dedicated push-up shaft body 37 for fitting and arranging the push-up plate 6 and pushing it up to the bottom side of the push-up plate.
is mounted on a shaft, and the push-up plate 3
6 (one end is not shown) and the reciprocating body 29 ₁ are dovetail-fitted 38 in order to smoothly reciprocate the up and down movement of the push-up plate. Note that the other basic configurations are the same as those of the previous embodiment, and therefore are given the same reference numerals.

In the configuration of the second embodiment, the push-up shaft 3
Since the pushing-up operation 7 can be performed arbitrarily, the following different effects can be obtained compared to the previous embodiment.

For example, in the configuration of the previous embodiment, when each plunger 31 pressurizes the resin material in each pot 9, corresponding to the amount of input and supply of each resin material,
Despite the pushing (elastic push-up) force of the elastic pushing member 32, each member moves downward separately. This is because the reciprocating body 29 moves relatively downward as it rises to a predetermined height position, and in reality, the pushing force of each elastic pushing member 32 is equally applied to each plunger 31. The pressing force on the resin material does not decrease. In such a state, in order to increase the pushing force of the elastic pushing member 32, the reciprocating body 29 may be further raised.

On the other hand, in the configuration of the second embodiment,
In order to further increase the pushing force of the elastic pushing member 32 ₁ ,
It is sufficient to raise the push-up plate 36 using the push-up shaft 37 without further raising the reciprocating body 29 ₁ . Therefore, it is possible to shorten the stroke required for the reciprocating motion of the reciprocating body 29 ₁ , and the overall shape of the molding machine can be further downsized.

(Effects of the present invention) According to the molding machine of the present invention, even if the amount of resin material supplied into the pot is different, the molten resin material can be injected under pressure into each cavity at the same time under the same conditions. Therefore, it is possible to reliably achieve constant quality of resin molded products.

In addition, in the molding machine of the present invention, by improving the pressurizing mechanism for the resin material, it is possible to downsize the structure and shape of the entire molding machine, making it easier to handle. This has excellent practical effects such as being able to reduce manufacturing costs. Furthermore, since it is easy to arrange and replace the elastic pushing member that pushes the plunger, the elastic pushing force can be selected as appropriate.
This has the effect of being able to appropriately and easily handle a variety of resin encapsulation molding operations.

Furthermore, based on the above-described configuration, the upper end of the plunger fitted into the pot thermally expands due to the temperature difference between the upper end and the base end of the plunger due to the temperature of the mold. Even if it becomes difficult to slide smoothly, the proximal end will not undergo thermal expansion, so it can maintain its flexibility (freely fitted state), contributing to improving the sliding action of the plunger. .

In addition, since the plunger and the elastic pushing member are configured to be separated via the seat, flexibility of the proximal end of the plunger (freely fitted state) can be ensured, and the axis of the plunger and the elastic pushing member can be secured. Even if there is a deviation in the center of the diameter, the seat interposed between the two will allow
It has the advantage that the displacement can be substantially and reliably absorbed, and the plunger can be easily replaced.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a partially cutaway vertical front view showing the main parts of a resin encapsulation molding machine for semiconductor devices, and FIG. This is a partially cutaway longitudinal side view showing the main parts of the machine, showing the pressurizing device when it is ascending and when it is descending, respectively. FIG. 3 is a partially cutaway plan view of the lower mold used in the molding machine, and FIG. 4 is a partially cutaway bottom view of the upper mold. FIG. 5 shows a second embodiment of the present invention.
FIG. 2 is a partially cutaway longitudinal sectional front view of the pressurizing device portion of the molding machine. 1... Molding machine, 4... Pressure device, 9... Pot, 29, 29 ₁ ... Reciprocating body, 30... Reciprocating drive mechanism, 31... Plunger, 31 ₁ ... Upper end, 31 ₂ ... Base end portion, 32, 32 ₁ ... elastic pressing member, 33 ... seat.

Claims (1)

[Scope of utility model registration request] In a resin encapsulation molding machine for semiconductor elements, which is equipped with an upper mold, a lower mold provided with a required plurality of resin material charging pots, and a pressurizing device for the resin material charged into each of the pots, The device includes: a plunger for pressurizing a resin material whose upper end is fitted into each pot, and whose base end is fitted into a lower reciprocating body separately; a vertical reciprocating drive mechanism for the reciprocating body; It is characterized by being composed of a seat that is individually engaged with the lower end surface of each of the plungers, and an elastic pushing member that elastically pushes each of the plungers upward separately through the seats. Resin encapsulation molding machine for semiconductor elements.