KR960007278B1 - Molding mould - Google Patents

Abstract

In a metal mold for molding presser consisting of an upper mold and a lower mold, the upper mold having an upper plate on which an upper chase is installed, an upper fixing plate, and an upper thermal insulating plate, and a lower mold having a lower plate on a lower fixing plate and a lower thermal insulating plate, and a lower chase mating with the upper chase, in which a cam support bar is installed on a lower mold, so that a cam is joined to a cam shaft to seesaw, and a pressure rod, pressing one side of the cam, is vertically installed through the center of the mold, and a lower moving plate is supported by the other side of the cam for up-and-down movement and elastically supported by a compression coil spring. Plungers are equidistantly disposed on the lower moving plate, and inserted into a port, filled with melted resin to be extended to the lower chase. The lower chase is provided with a runner block in which packages are placed. The upper chase and a lower cavity block are coupled to the upper plate on the upper mold mating with the lower mold so the plunger on the lower moving plate elevated to the cam transfers the meltedd resin within the port.

Description

Mold of Molding Press Device for Enclosure Molding

1 is a plan view showing a lead frame in front and in order to explain an example of encapsulation in a semiconductor chip.

2 is a view showing a conventional embodiment of encapsulating the lead frame of FIG.

Figure 3 is an illustration of a conventional molding press apparatus.

4 is an exemplary view of a conventional transfer molding press provided with a plurality of plungers.

5 is an illustration of a conventional molding die improved over FIG.

6 is a conceptual diagram of operating the mold using the hydraulic device of the third.

7 is a front view and a side view of a mold according to the present invention.

8 is a plan view of the lower mold in FIG.

9 is a view showing the configuration of the upper mold from the bottom of FIG.

10 is an enlarged view of the chase, (a) is a plan view of the upper chase, (b) is a bottom view of the lower chase.

* Explanation of symbols for main parts of the drawings

1: Lead Frame 2: Package

3: CULL part 4: Gate

5: runner 6: press moving plate

8: Press Rod 9: Stroke

10: mold seating portion 11: hydraulic cylinder

12: Hydraulic Line 13: Plunger

14: hydraulic block 15: runner block

16: upper mold 17: runner block

16: upper mold 17: lower mold

20: pressure rod

23, 24: Upper and lower cavities block

25, 26: upper and lower chase 28: heater hole

31, 32: upper and lower plate 33: gears (rack and pinion)

34: support rod 35: lower fingerboard

36: cam support rod 37: cam

38, 39: upper and lower signs 40, 41: upper and lower moving plates

42,43: Upper and fixed plate 44,45: Insulation plate

46: upper support block 48: lower limb support

49: stopper 50: port

51: spring block 52: camshaft

53: compression coil spring 54: cushion block

55: spring 56: roller

L: Stroke length

The present invention relates to a mold of a molding press device for encapsulation. Specifically, the resin for encapsulation is pressurized by a cam driving method to improve the quality of a molded plate semiconductor package and to waste the molding resin. The present invention relates to a mold designed to be applied to a conventional molding press apparatus while having a plurality of ports and plungers as close as possible to the cavity (CAVITY) where the semiconductor package is molded so as to minimize the size.

Encapsulation is a molding method in which a processed product is coated with a resin. In the example of FIG. 1 related to the present invention, a semiconductor chip can be cited.

In other words, the semiconductor package is hardly adhered to the upper and lower parts of the lead frame 1 by pressing an epoxy molding compound, which is a thermosetting resin, to prevent damage after attaching the semiconductor chip on the lead frame 1. A lead frame, ie, a strip, is formed to have a plurality of packages (2, PACKAGE) in which the compound is hardened and the compound is coated on the reframe.

In the conventional molding press apparatus for this purpose, as shown in FIG. 2, the compound is first extruded into the curl portion 3 and passes through the runner 5 portion and the gate 4, and thus the groove portion of the package 2 is formed. CAVITY) is pressed by high pressure to reach.

However, since the compound is PRE-HEATING in the first solid state and then heated in the keel portion 3 to become a liquid state and reaches the package 2 portion, the pressure of the first melted portion and the last melted portion is constant. It does not work, and the distance to the coating step is not constant, which causes various problems in encapsulation, which adversely affects the integrated circuit directly or indirectly in the package 2, in which case the molding of the semiconductor package is completed. Even if it is, it becomes unusable and causes a lot of losses.

In addition, only the portion of the package (2), which is actually molded, needs to be coated with the compound. Since the portion of the kernel (3) or the runner (5) plays a role in the production of the product, it is only necessary indirectly and disposed of after the product. In this case, there has been a need to reduce the wasted passageway as this would waste expensive epoxy molding compound.

On the other hand, the conventional molding press apparatus is the most widely used in the market as the third degree, the configuration is fixed to the upper and lower parts after the mold is mounted on the mold seating portion 10, the molding order is After the press moving plate 6 has risen into the stroke length L of the press moving plate and the upper part and the lower part are in close contact with each other, the press rod 8 moves upward to put the compound in the hole centered at the upper part, and then press It moves downward in the stroke 9 of the rod 8, extrudes the compound from the portion 3 of FIG. 2, flows through the runner 5 and the gate 4 to the product, and then solidifies to form the desired encapsulation. The product will be produced.

Therefore, a new type of mold has been developed to solve the non-uniformity and economicality of the above-mentioned conventional molding, which is different from the conventional one press rod 8 forming one epoxy molding compound mass. By having a plurality of plungers (3) to play a role of having a structure for molding molding.

As a result, the cut portion and the runner portion are reduced, thereby reducing the molding material and maintaining a constant pressure between the cavities, thereby enabling high quality molding.

However, as the number of plungers 13 increases, as shown in FIGS. 4 and 5, the method of driving the plunger is changed, so that a separate molding press for molding (molding) using such a mold is required. It became.

But. As the penetration rate of the existing transfer molding presses is remarkable, using a press of such an improved type using such presses, a high quality and low cost molding method is required. Modified methods of use have been devised.

However, the mold apparatus of this type removes the hydraulic line 12 driving the press rod 8 from the hydraulic cylinder 11 to move the plunger 13 using one or two hydraulic blocks 14. Therefore, it is necessary to modify the existing molding press machine as shown in FIG. 3 and also use hydraulic pressure, so there is a risk of leakage of oil when used for a long time even when sealing, and the temperature in the press machine is about 175 ℃ Due to the change in the intrinsic nature of the fluid to maintain a constant value it could not be ignored the concern that adversely affect the operation of the plunger (13).

Therefore, in the present invention, as a principle for encapsulating the resin, using a kinematic structure of the plunger lifting method using a cam, the plunger is not exposed in the port, and the existing transfer molding press (FIG. 3) It is a device designed to bring good molding and manufacturing cost savings by using a new type of mold without modification.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to the upper and lower molds (16) and (17) of the molding press for encapsulation molding, wherein the upper and lower molds (31) and (32) are placed on the upper and lower chases (25) and (26). Lower cavity blocks 23 and 24 are provided, and lead frames 1 are placed in the upper and lower cavity blocks 23 and 24 to be mounted to the upper and lower cavity blocks 23 and 24. The molten resin is pressurized to encapsulate the lead frame 1 along the runner 5 of the runner block 15, but the cam support rod 36 is installed on the lower mold 17 so that the cam shaft 52 The cam 37 is installed so as to perform the shiiso movement, and the pressure rod 20 is vertically installed through the lower mold 17 so as to press one side of the cam 37. The press rod of FIG. A through hole is provided to allow the pressure rod 20 to be pushed down by the lower portion 8, and the other side of the cam 37 is a high copper plate 41 integrally coupled with the plunger 13 on the cushion block 54. Float to the bottom The high copper plate 41 has a configuration in which the rack is supported by a restoring spring on the spring block 51 while the rack is horizontally elevated by a gear 33 composed of a pinion.

In addition, the lower chase 26 is coupled to the runner block 15 so that each plunger 13 is lifted and the package 2 is double-arranged around the port 50 filled with a resin (compound). The molten resin pressurized from (50) is enclosed in the package (2) via the runner (5), so that the amount and pressure of the molten resin pressurized at any port (50) is designed to be uniform so that the molding package (2) is uniform. To be completed.

7 is a configuration diagram of the present invention, which is viewed from the front side on the left side and from the right side on the basis of the center vertical line.

Therefore, each part has a pair of left and right symmetrically installed, 16 is the upper mold, 17 is the lower mold. An upper chase 25, an upper cavity block 23, and a runner block 15 are coupled to the upper mold plate 31 of the upper mold 16, and a heater is built in the heater hole 28 to maintain a molten state of the resin. It is coupled to the upper fixing plate 42 through the upper support bar (34), the reference numeral 40 in the figure is a phase shift plate, 44 is the upper hot plate, 49 is the stopper, 55 is the spring.

In addition, the plunger 13 is operated like a piston in the ports 50 arranged at equal intervals, and the molten resin is filled in the port 50 so that the plunger 13 is pumped when the plunger 13 is raised, and one end of the high copper plate 41 is Combining integrally with the rack to form a gear 33 to be elevated in the horizontal state with the pinion, the lower side of the high copper plate 41 is supported by one side of the cam (37), the lifting action of the cam (37) Movement), the high copper plate 41 is lifted together.

In the contact surface between the high copper plate 41 and the cam 37, a medium such as a roller 56 is provided in the cam 37 to prevent friction and scratching.

In particular, the cam 37 is supported by the center of the cam shaft 52 to support the high copper plate 41, but the other side is in contact with the pressure rod 20 and the roller 56 to maintain a horizontal state While, as described in the operation description described below, the pressing action of the pressure rod 20 raises and lowers the plunger 13 on the high copper plate 41 while moving the cam 37.

In the drawings, reference numeral 43 denotes a fixed plate, and 45 denotes a lower hot plate.

8 is a plan view of the lower mold 17 of the mold according to the present invention, wherein the cam 37 driving pressure rod 20 has four sets of packages 2 (chase) centered on an operating position. The arranged example is shown.

That is, the pressure rod 20 is for elevating the high copper plate 41 in FIG. 7, and a plunger 13 is disposed for each port 50 of the runnable shock 15, and the port 50 and Each package 2 is encapsulated with resin along the associated runner 5 and the gate 4. In particular, the high copper plate 41 is a gear consisting of racks and pinions in the upper, lower, left and right sides. Supported by (33), the lifting and lowering of the high copper plate 41 in the horizontal state to prevent the tilting, so that the up and down movement of each plunger 13 is kept the same, so that a constant resin in any package (2) Supplied.

10 shows the structure of the upper chase 25, a shows the upper chase 25, and b shows the lower chase 26. The runner 5 and the collar 3 are connected to each other. A constant pressure is applied to each molded product (package 2) when the plunger 13 is elevated.

Next, the operation of the present invention according to the above configuration will be described.

The present invention of FIGS. 7 to 10 is set in the mold seating portion 10 in a conventional molding press apparatus (FIG. 3), and the lower part of the mold is lifted by the press moving plate 6 to be seated in position. When the press rod 8 is lowered by the hydraulic cylinder 11 and the pressure rod 20 is pressed, one side of the cam 37 is pressed.

At this time, since the cam 37 is supported by the camshaft 52, the other side holding the high copper plate 41 is raised, so that the plunger 13 provided on the high copper plate 41 is raised in the port 50. At this pressure, the compound (resin) starts extrusion through the keel portion 3 and the runner 5.

At this time, the high copper plate 41 is raised while being leveled by the gear 33, and thus, ultimately, the sealing pressure of the compound and the supply amount thereof uniformly act on any package.

Here, the compound is pumped along the runner 5 in the runner block 15 to the upper and lower cavity blocks 23 and 24. At this time, the temperature is increased to prevent solidification. Since the heater is built in 28, the upper and lower chases 25 and 26 and the upper and lower cavity blocks 23 and 24 are heated, and the enclosed compound is solidified after a predetermined time in the groove.

Then, the normal ejector pin (not shown) is operated in the reverse order, and the upper intermediate plate 38 is moved by the compression coil spring 53, and the movable plate 40 is moved so that the molded package 2 ), The end of one cycle of work process for sealing molding.

Here, the cushion block 54 allows the plunger 13 pressure applied in each cavity block 24 to act equally, and the high copper plate 41 is provided by the compression coil spring 53 in the spring block 51. When it moves downward, it is installed so that it can move to an upward direction and a circular direction again.

On the other hand, in Figure 8 and 9 has a structure having four chases, it is obvious that the number of chases can be increased or decreased as needed, even if there are some structural changes for this purpose is the scope of the present invention It belongs to.

In addition, in FIG. 10, one chase shown in FIG. 8 and FIG. 9 is divided into upper and lower parts. The plunger 13 can be extruded by connecting the runner 5 and the collar 3 to each other. The pressure is then made constant on each molded package 2.

As described above, the present invention has a great advantage that it can be used as it is in a conventional molding press device, which is widely used, and there is no fear of incomplete molding because it is arranged at equal intervals from the runner to the package. Since uniform pressure acts, there is almost no wire sweeping, and there is no internal and external void (INTRNAL, EXTERNAL VOID) generated as a result of non-uniform molding inside the semiconductor package during molding. '

In addition, since the compound conveying distance is short, there is no unnecessary compound consumption than the conventional mold, and since the plunger is always located in the port, there is no temperature drop due to contact with air, thereby extending the life of the device.

Claims (4)

The upper mold 16 and the lower mold 17, the upper mold 16 is composed of the upper plate 31, the upper fixing plate 42 and the upper hot plate 44, the upper chase 25 is installed, The lower mold 17 has a lower mold 32 on the fixing plate 43 and the lower heat plate 45, and the lower chase 26 is formed to mate with the upper chase 25. In the mold of the molding press apparatus, a cam support rod 36 is provided on the lower mold 16 so that the cam 37 is assembled on the cam shaft 52 so as to perform a seesaw operation, and one side of the cam 37 is mounted. The pressing pressure rod 20 is installed vertically by penetrating the center of the mold, and the high copper plate 41 supported by the other side of the cam 37 is lifted and supported by the compression coil spring 53. The plunger 13 is disposed on the copper plate 41 at equal intervals, and the plunger 13 has a piston function in the port 50 filled with the molten resin. It is inserted so as to extend to the lower chase 26, the runner block 15 is installed in the lower chase 26, the package 2 is placed, the upper mold 16 and the lower mold 17 and The pair of lower chases 26 and the upper chase 25 and the lower cavity block 24 of the structure capable of sealing molding are coupled to the upper plate 31, and the high copper plate 41 is elevated by the cam 37. The mold of the sealing press molding press device, characterized in that the upper plunger 13 is configured to pressurize the molten resin in the pot 50. The method of claim 1, wherein the high copper plate 41 is supported by a gear 33 consisting of a rack and pinion coupled to the upper, lower, left, right, so as to maintain the horizontal, the lifting molding cap Mold of the wooling press device. 2. The mold of the molding press apparatus for sealing molding according to claim 1, wherein the upper mold (16) and the lower mold (17) are provided with a plurality of upper and lower chases (25) (26). The mold according to claim 1, wherein the cam (37) driven by the pressure rod (20) is restored by the force of the compression coil spring (53) in the spring block (51).