JPH08264579A - Resin mold method of electronic component and resin mold device - Google Patents

Abstract

PURPOSE: To surely remove unnecessary resin attaching to a lead frame by holding a lead frame at a position wherein a through hole thereof corresponds to a groove part of a connection path and receiving molten resin leaking out to a connection path inside a groove part. CONSTITUTION: A lead frame 1 with a through hole 1a is held by upper and lower molds 3, 2 and a cavity 8 shaped in a fitting surface of the upper and lower molds 3, 4 is filled with molten resin. Simultaneously, air inside the cavity 8 it communicates with an outside of the upper and lower molds 3, 2 and is exhausted to an outside of the upper and lower molds 2, 3 through a communication path 9 with a groove part 10 whose corner part is chamfered in a side near the cavity 8 and a resin mold part is formed covering a semiconductor chip on the lead frame 1. In such a resin mold method of an electronic component, the lead frame 1 is held by the upper and lower molds 3, 2 at a position wherein the through hole 1a corresponds to the groove part 10 of the communication path 9 and molten resin leaking out to the communication path 9 is received inside the groove part 10 in the state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding method for an electronic component such as an IC and a diode, which includes a step of molding a resin molding portion in a cavity formed on the mating surfaces of upper and lower molding dies, and a molding apparatus therefor. In particular, the present invention relates to a resin molding method and a resin molding apparatus for an electronic component, which is characterized by the shape of a communication path for letting air in a cavity escape to the outside of the mold.

[0002]

2. Description of the Related Art Generally, molding of a resin mold portion of an electronic component such as an IC using a metallic lead frame of iron or the like is performed as follows. That is, as shown in FIGS. 6 and 7, a resin pot 33 for accommodating a resin tablet 32 made of epoxy resin or the like, and a runner groove 34 connected to the resin pot 33 and extending along the longitudinal direction of the lead frame 31.
Also, a lower mold 37 having resin molding cavity 36 communicating with a plurality of gate grooves 35 branched from the runner groove 34 formed on the mating surface, and a cavity 38 (see FIG. 6) at a position corresponding to the cavity 36. The strip-shaped lead frame 31 is sandwiched between the upper mold 39 and the upper mold 39, and the heated and melted resin in the resin pot 33 is lifted by a plunger (not shown) from the runner groove 34. By guiding the semiconductor chips (not shown) mounted at regular intervals along the longitudinal direction of the lead frame 31 by introducing the electrons into the cavities 36 and 38 through the gate groove 35, each electronic device is sealed. The resin mold part 40 of the component is molded.

On the mating surface of the lower mold 37, a communication passage 41 for bleeding air in the cavities 36, 38 is carved from the cavities 36, 38 toward the side surface of the lower mold 37. In the communication passage 41, a rectangular parallelepiped groove 42 is formed near the cavity 36. Therefore, the molten resin is filled while removing the air in the cavities 36 and 38 into the communication passage 41, and also enters the communication passage 41 with the removal of the air, and the excess resin flows into the groove portion 42. It is stored. As a result, part of the molten resin
The lead frame 31 is integrally formed with the resin mold portion 40.
It is molded as the unnecessary resin 43 in a state of being attached to the lower surface (see the shaded portion in FIG. 7). It should be noted that a substantially rectangular through hole 31 a formed in the lead frame 31 is located on the groove 42. Therefore, as shown in FIG. 8A, the unnecessary resin 43 is in a state of being attached to the periphery of the through hole 31a on the lower surface of the lead frame 31 (the attached portion is shown by hatching).

After the lead frame 31 is released from the upper and lower molds 37, 39, it is transferred to the next step by a transfer means such as a suction collet. In the next step, the lead frame 31 (not shown here) is placed on the fixed base in a state of being held by the holding means, and in this state, the substantially cylindrical ejection pin is attached to the cylinder or the like. Through the through hole 31a of the lead frame 31 by driving
The undesired resin 43 formed under the through hole 31a is pressed downwards and is peeled off from the lower surface of the lead frame 31.

Further, in the next step, the unnecessary resin 43b formed on the lower surface of the lead frame 31 by the communication passage 41 between the resin mold portion 40 and the unnecessary resin 43 is immersed in a solution such as pyrrolidone. It is peeled off from the lead frame 31 by being melted.

[0006]

However, the conventional resin molding method described above has the following problems. When the unnecessary resin 43 is pressed by a protrusion pin (not shown), a peeling force is applied to a portion where the unnecessary resin 43 is attached to the lower surface of the lead frame 31, but in this case, the lead frame 3
1 In the adhesion portion with the lower surface, the force of peeling from the lead frame 31 becomes weaker as the distance dimension from the peripheral edge of the through hole 31a becomes larger. The force of peeling is smaller than that of other adhered parts. Therefore, a part of the unnecessary resin 43 is, as shown in FIG.
In some cases, the corner portions 43a could not be completely peeled off from the lower surface of the lead frame 31 and remained as resin burrs in the state of being attached to the lead frame 31.

The undesired resin 43, which remains attached in such a state, cannot be completely dissolved by the above solution because of its large thickness. Therefore, the lead frame 31 is transferred to a step of performing punching processing such as lead cutting or lead bending processing while the unnecessary resin 43 remains, and for example, when the lead frame 31 is arranged between the upper and lower molds used for these processing, In some cases, the positioning accuracy may be insufficient due to the unnecessary resin 43 riding on the mounting surface of the mold, and in this case, there is a problem that lead punching failure, bending failure, or the like may occur.

The present invention has been conceived under the circumstances as described above, and it is an object of the present invention to provide a molding method and a molding apparatus for an electronic component capable of reliably removing a predetermined portion of unnecessary resin adhering to a lead frame. To aim.

[0009]

In order to solve this problem, the present invention is designed to sandwich a lead frame having a through hole between upper and lower molds and melt it in a cavity formed in a mating surface of the upper and lower molds. While filling the resin, the air in the cavity is communicated with the outside of the upper and lower dies, and is discharged to the outside of the upper and lower dies through a communication passage having grooves with chamfered corners in the vicinity of the cavity. A resin molding method for an electronic component, wherein a resin molding portion is molded so as to cover a semiconductor chip on a frame, wherein the lead frame is sandwiched by the upper and lower molds at a position where a through hole corresponds to a groove portion of the communication passage. The present invention provides a resin molding method for an electronic component, characterized in that the molten resin leaking to the communication passage in this state is housed in the groove.

Further, according to the present invention, a cavity is formed on the mating surfaces of the upper and lower molds and molds a resin mold portion covering the semiconductor chip on the lead frame, and at least one mating surface of the upper and lower molds is engraved. A resin molding device for an electronic component, comprising: a communication passage that is provided and that communicates the cavity with the outside of the upper and lower dies, wherein the communication passage includes:
There is provided a resin molding device for an electronic component, which has a groove portion in the vicinity of the cavity, and a corner portion of the groove portion is chamfered.

Furthermore, the present invention provides the resin molding apparatus for an electronic component, wherein the corner portion of the groove is chamfered into an R shape in the above resin molding apparatus.

[0012]

According to the present invention, the molten resin discharged from the cavity into the communication path together with the air in the cavity is located below the through hole of the lead frame and has a chamfered corner. As it is stored in the groove,
It is molded as an unnecessary resin in a state where the corners are chamfered so as to follow the shape of the groove. Therefore, even if the unnecessary resin in the groove is molded in a state of adhering to the periphery of the through hole and / or the inside of the through hole on the surface of the lead frame, this unnecessary resin is It is possible to perform molding so that the outer edge and the peripheral edge of the through hole have substantially uniform width dimensions.

That is, when the unnecessary resin is pressed against the through hole by a vertically movable pin, for example, a peeling force is applied almost uniformly to all parts attached to the lead frame surface. Therefore, it is possible to reduce the amount of residual corner burrs remaining as resin burrs. Therefore, according to the present invention, it is possible to reduce the adhesion residue of the unnecessary resin molded in the groove portion to the lead frame, and accordingly, the mounting and transfer of the lead frame in the next step of the resin molding step can be performed. It can be done smoothly.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below by taking an IC as an electronic component as an example with reference to FIGS. 1 to 5, but the present invention is not limited thereto. Figure 1
It is a perspective view showing the important section of the device which molds the resin mold part of IC. Further, FIG. 2 is a cross-sectional view of an essential part showing a state in which the lead frame is sandwiched by the upper mold in the above apparatus.

In this device, a resin mold portion is formed on a strip-shaped lead frame 1 to cover semiconductor chips (not shown) mounted at regular intervals in the longitudinal direction, and the lead frame 1 is vertically moved. It is composed of a lower mold 2 and an upper mold 3 which are made of cemented carbide and are sandwiched between the two. The lower mold 2 is fixed on a base (not shown),
Further, on a mating surface with the mold 3, a resin pot 5 for accommodating a cylindrical resin tablet 4 made of an epoxy resin as a molding resin material, and connected to this, extends along the longitudinal direction of the lead frame 1. Runner groove 6, a plurality of gate grooves 7 branched from this runner groove 6, and each gate groove 7
A cavity 8 for molding a resin mold portion, which communicates with the above, and a communication passage 9 having a concave shape in cross section (a cross section taken along arrow A in FIG. 1) which communicates with the cavity 8 to the outside of the mold are engraved.

As shown in FIG. 3, the communication passage 9 is provided with a substantially rectangular parallelepiped groove portion 10 in the vicinity of the cavity 8. The four corners 10a of the groove 10 are chamfered. As shown in FIG. 2 (FIG. 2 is a cross-sectional view of the main parts when the upper and lower molds 2 and 3 are clamped), the upper mold 3 is lowered by the expansion and contraction movement of a hydraulic cylinder (not shown). It moves up and down with respect to the mold 2, and on the mating surface with the lower mold 2, a cavity 12 facing the cavity 8 and a circular concave portion 11 facing the resin pot 5.
And are engraved.

The resin mold portion of the IC is molded as follows using the apparatus having such a configuration (FIGS. 1 and 2).
reference). First, in a state where the lead frame 1 is suction-held by a suction collet (not shown), the lower mold 2 opened.
And the upper die 3 are transferred. Next, the semiconductor chips (not shown) mounted on the island of the lead frame 1 are located on the cavities 8, respectively, and the substantially rectangular through holes 1a formed in the lead frame 1 are formed into the lower mold. It is placed so as to be located on the groove portion 10 of 2. Then, the lead frame 1 is sandwiched between the upper mold 3 and the lower mold 2 as the upper mold 3 moves downward toward the lower mold 2 by the extension of the hydraulic cylinder (not shown). At this time, each semiconductor chip on the lead frame 1 is in a state of being surrounded by the cavities 8 and 12 (hereinafter, the space surrounded by the cavities 8 and 12 is referred to as a cavity 13). Thereafter, a heater (not shown) provided inside the lower mold 2 with the resin tablet 4 stored in the resin pot 5 in advance by the conventional suction conveyance method.
The molten resin is melted by heating, and the molten resin is pressed by the rise of a plunger (not shown) fitted in the resin pot 5 to be pressed into the cavity 13 through the runner groove 6 and the gate groove 7 and then into the lead frame 1. Fill so as to cover the upper semiconductor chip.

At this time, in the cavity 13,
The molten resin is filled so as to push air into the communication passage 9, and a part of the molten resin enters the communication passage 9 so as to be drawn into the air and is stored in the groove portion 10 provided in the communication passage 9. The molten resin stored in the groove 10 is shown in FIG.
As shown in FIG. 4 (FIG. 4 is a bottom view of the main part of the lead frame 1), the corners 14 a are attached to the inside of the through hole 1 a on the bottom surface of the lead frame 1 and the periphery thereof, and the corners 14 a of the groove 10 are formed. The unnecessary resin 14 is molded so as to have an R chamfered shape following the shape of 10a.

The unnecessary resin 14 is molded so that the width dimension from the outer edge to the peripheral edge of the through hole 1a is substantially uniform in the portion (hatched portion in FIG. 4) attached to the surface of the lead frame 1. At the same time as the molding of the unnecessary resin 14, the resin mold portion 15 is molded in the cavity 13 so as to be connected to the unnecessary resin 14. In this state, the lead frame 1 is released from the upper and lower molds 2 and 3 and transferred to the next step by a conventional suction transfer method (not shown).

In the next step, as shown in FIG. 5, a fixed base 16 is provided, and the lead frame 1 is placed on this base 16. Then, by lowering the protruding pin 17 made of substantially cylindrical aluminum that can move up and down by the cylinder drive with respect to the base 16,
The unnecessary resin 14 on the lead frame 1 is pressed. At this time, the unnecessary resin 14 is applied with a uniform peeling force to all the parts attached to the surface of the lead frame 1, so that the corners 14a are less likely to remain as resin burrs. It becomes possible.

Therefore, according to the present invention, it is possible to reduce the adhesion residue of the unnecessary resin 14 on the lead frame 1. Regarding the groove portion 10 in the present invention, the corner portion 10
The chamfered shape of a may be a C-chamfered shape, but is not limited thereto. Further, in the present embodiment, the communication passage connected from the cavity is engraved only in the lower mold, but the invention is not limited to this.
The effect of the present invention can be obtained by providing only the upper die or both the upper die and the lower die.

Further, the groove 10 is preferably provided in the vicinity of the cavity, but the distance from the cavity 14 is not limited to this. In addition, although the upper mold is movable in the present embodiment, it is also applicable to a mold in which the lower mold is movable or both the upper and lower molds are movable. When the communication passage is provided only in the upper mold, it becomes easy to surely remove the unnecessary resin formed in the groove.

[Brief description of drawings]

FIG. 1 is a main part perspective view showing an apparatus for molding a resin mold portion of an IC in this embodiment.

FIG. 2 is a cross-sectional view of essential parts showing an apparatus for molding a resin mold portion of an IC in this embodiment.

FIG. 3 is an enlarged perspective view of an essential part showing a groove formed in a communication passage in the present embodiment.

FIG. 4 is a bottom view of essential parts showing a lead frame molded with an unnecessary resin in the present embodiment.

FIG. 5 is an explanatory view for explaining a manner of peeling unnecessary resin from the lead frame in the present embodiment.

FIG. 6 is an explanatory diagram illustrating a method of molding a resin mold portion of a conventional IC.

FIG. 7 is an explanatory diagram illustrating a method for molding a resin mold portion of a conventional IC.

FIG. 8 is an explanatory diagram for explaining a state in which a part of the unnecessary resin remains attached to the lead frame in the conventional method of molding the resin mold portion of the IC.

[Explanation of symbols]

 1 Lead Frame 2 Lower Mold 3 Upper Mold 4 Resin Tablet 5 Resin Pot 6 Runner Groove 7 Gate Groove 8 Cavity 9 Communication Passage 10 Recess 11 Through Hole 12 Extrusion Pin 13 Cavity 14 Recess 15 Through Hole 16 Extrusion Pin 17 Cavity Tee 18 unnecessary resin

Claims (3)

[Claims] 1. A lead frame having a through hole is sandwiched by upper and lower dies, and a molten resin is filled in a cavity engraved on a mating surface of the upper and lower dies, while air in the cavity is moved upward and downward. It is discharged to the outside of the upper and lower molds through a communication passage that communicates with the outside of the mold and has a chamfered groove in the vicinity of the cavity, and a resin mold portion is molded so as to cover the semiconductor chip on the lead frame. A method of resin molding an electronic component, wherein the lead frame is sandwiched by the upper and lower molds at a position where the through hole corresponds to the groove portion of the communication passage, and molten resin leaking to the communication passage in this state is A resin molding method for an electronic component, characterized by housing in a groove. 2. A cavity formed in a mating surface of the upper and lower molds and molding a resin mold portion covering the semiconductor chip on the lead frame; and a cavity formed in at least one mating surface of the upper and lower molds. And a communication path for communicating the upper and lower molds with each other, wherein the communication path has a groove in the vicinity of the cavity, and a corner portion of the groove has a chamfered shape. A resin molding device for electronic parts, characterized in that 3. The resin molding apparatus for an electronic component according to claim 2, wherein the corners of the groove are chamfered into an R shape.