JPH0832003A - Manufacture of electronic component - Google Patents

Abstract

PURPOSE:To prevent damage to a resin mold, by a method wherein either one of an upper die or a lower die is made to abut against the facing surface of a suspension lead, and, in this state, the other is pressed against unnecessary resin, thereby cutting the suspension lead. CONSTITUTION:A lead frame in the state that unnecessary resin is linked with a resin mold 34 and adheres to the lower surface of a suspension lead is transferred to a part between a lower die 1 and an upper die 2, and each resin mold 34 is mounted. The upper die 2 is moved downward to the lower die 1 and clamps the outer frame of a lead frame 31. Further the upper die 2 is moved downward, presses a mounting stand 4, and is lowered by the elastic contraction force of a compression spring 9. Protruding parts 5 in a penetrating hole 10 protrude gradually from the upper surface of the mounting stand 4, and the unnecessary resin is cut off from the resin mold part 34. By applying a shearing force in the pressing direction, the resin mold 34 is separated from the lead frame.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electronic component such as an IC using a lead frame, and more particularly to a method for separating a resin mold portion from the lead frame.

[0002]

2. Description of the Related Art Generally, a band-shaped lead frame made of metal such as iron is used for manufacturing electronic parts such as ICs and diodes. This lead frame has islands for mounting semiconductor chips, a plurality of suspension leads for suspending the islands, and a plurality of lead terminals facing the islands formed at regular intervals along the longitudinal direction. It will be. The suspension leads are connected to the outer frame of the lead frame. An electronic component is conventionally manufactured as follows using such a lead frame.

Taking an IC manufacturing method as an example, a semiconductor chip mounted on each island of a lead frame is connected to each lead terminal through a wire made of gold or the like, and then the semiconductor chip, the wire and the lead are connected. A part of the terminal is sealed by molding a resin mold portion with a thermosetting resin such as an epoxy resin. This resin mold part is molded by injecting the molten resin along the lower surface of the suspension lead into the resin mold part molding cavity in the mating surfaces of the upper and lower molds made of cemented carbide or the like. At this time, as shown in FIG. 4, the unnecessary resin 33 adheres to the lower surface of the suspension lead 32 of the lead frame 31 in a state of being connected to the resin mold portion 34. Next, this lead frame is mounted on the lower mold surface of the upper and lower molds made of cemented carbide in the next step, and further, the upper mold is lowered toward the lower mold to hit the upper surface of the suspension lead. With the outer frame of the lead frame sandwiched between them, the push-up punch made of cemented carbide provided on the lower die side is lifted while pushing up the resin mold part to lift the resin mold part from the suspension lead. Separate it from the lead frame by tearing it off.

[0004]

However, as shown in FIG. 5, the resin mold portion is applied with a tensile force to the suspension lead 32 while being pushed up by the push-up punch 35 by the unnecessary resin 33. Since the reaction force against the tensile force is applied, the surface of the unnecessary resin 33 is separated from the lead frame 31 at the connecting portion with the unnecessary resin 33, so that the unnecessary resin 33 in the resin mold portion 34 is removed. However, there is a problem in that the peeled portion is likely to be chipped and an appearance defect is generated.

The present invention has been conceived under the circumstances as described above, and an object thereof is to provide a method of manufacturing an electronic component that does not cause a chip in a resin mold portion.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a resin mold portion hung on a suspension lead in a connected state with an unnecessary resin attached to a suspension lead formed on a lead frame is removed from the lead frame by using an upper mold and a lower mold. In a method of manufacturing an electronic component including a step of separating, in a state in which one of the upper and lower molds is in contact with an opposing surface of a suspension lead, the other is pressed toward an unnecessary resin, and the suspension lead is cut. A method of manufacturing an electronic component is provided.

The present invention further provides the above-mentioned method of manufacturing an electronic component, characterized in that a protrusion provided on the other of the upper and lower dies is pressed against the unnecessary resin.

[0008]

In this structure, when the unnecessary resin attached to the suspension leads is pressed against the other of the upper and lower molds while one of the upper and lower molds is in contact with the facing surface of the suspension lead, the unnecessary resin is removed from the resin mold portion. The shearing stress along the pressing direction is concentrated and added to the connecting portion, and a crack progresses along the pressing direction, and finally the connecting portion is cut. Immediately after or simultaneously with this, the suspension lead is separated from the resin mold portion by shearing stress in the pressing direction applied thereto and cutting.

Therefore, according to the present invention, when the electronic component is manufactured, the unnecessary resin is pressed so that the suspension lead is cut at the connecting portion between the unnecessary resin and the resin mold portion substantially along the pressing direction. Since it is possible to cut the resin mold, the surface of the resin mold portion is hardly chipped, and the occurrence of defective appearance is significantly reduced.

[0010]

EXAMPLE An example of the present invention will be described below, taking an IC manufacturing method as an example, and the unnecessary resin 3 as described above and shown in FIG.
1 to FIG. 3 focusing on the step of separating the resin mold portion 34 from the lead frame 31 in the case where the lead frame 31 is connected to the resin mold portion 34 and attached to the lower surface of the suspension lead 32. However, the present invention is not limited to this.

FIG. 1 is a perspective view of essential parts showing a molding apparatus for cutting the suspension leads 32 when the resin mold portion 34 is separated from the lead frame 31. This molding apparatus comprises a lower mold 1 and an upper mold 2. The lower mold 1 is composed of a fixed base 3 made of cemented carbide that is fixedly mounted on a base not shown, and a mounting base made of cemented carbide that can be moved downward toward the fixed base 3 by pressing from above. 4 is provided.

On the upper surface of the fixed base 3, a set of two protrusions 5 having a convex shape, which are protruded at a predetermined interval, are provided in a row at regular intervals, and the protrusions 5 of each set are provided. Through-holes 6 are formed in the respective spaces. A cylindrical push-up punch 7 is provided in the through hole 6 so as to be movable up and down by expansion and contraction of a hydraulic cylinder (not shown) mounted on a base. Further, columnar slide shafts 8 made of iron are erected on the square portions on the upper surface of the fixed base 3, and compression springs 9 are attached to the slide shafts 8.

The mounting table 4 has a lead frame 3 on its upper surface.
1 is for mounting. Further, on the upper surface of the mounting table 4, substantially rectangular through holes 10 are formed at positions corresponding to the resin mold portions 34 of the lead frame 31, respectively. Further, the mounting table 4 has circular through holes 11 formed in the square portions, and these through holes 8 are formed.
The slide shaft 8 is loosely fitted to the fixed base 3 and is held on the compression spring 9 in a state of being separated from the fixed base 3 by a predetermined distance.
At this time, a pair of protrusions 5 and push-up punches 7 are in the respective through holes 10.

The upper die 2 moves up and down with respect to the lower die 1 by the expansion and contraction of a hydraulic cylinder (not shown), and the mating surface with the lower die 1 has a substantially rectangular through hole. 12 are drilled at positions corresponding to the through holes 10 of the lower mold 1, respectively. Using the molding apparatus having such a configuration, the resin mold portion 34 is separated from the lead frame 31 in the following procedure.

First, while holding the lead frame 31 by a chuck mechanism (not shown), the lead frame 31 is transferred between the upper and lower molds 1 and 2 in the mold open state so that the resin mold portions 34 are respectively positioned in the through holes 10. Then, it is mounted on the mounting table 4. Next, the upper die 2 is moved downward toward the lower die 1, the outer frame of the lead frame 31 is sandwiched, and further, the upper die 2 is moved down in this state to press the mounting table 4. As a result, the mounting table 4 is lowered by the elastic contraction force of the compression spring 9. At this time, as the mounting table 4 descends, the projections 5 in the through holes 10 gradually come to a state of protruding from the upper surface of the mounting table 4.

At this time, as shown in FIG. 2, the unnecessary resin 33 attached to the suspension leads 32 is directly pressed by the protrusions 5 and pushed up together with the suspension leads 32. Since the shear stress along the pressing direction is concentrated and applied to the connecting portion between 33 and the resin mold portion 34, as the unnecessary resin 33 is pushed up, a crack progresses along this pressing direction, and finally, The unnecessary resin 33 and the resin mold portion 34 are cut. Further, even after the unnecessary resin is cut, the suspension lead 32 is cut by applying shearing stress to the hanging lead 32 in the pressing direction, thereby separating the resin mold portion 34 from the lead frame 31.

After that, the push-up punch 7 is lifted by the extension of the hydraulic cylinder to push up the resin mold parts 34 which have already been separated by a predetermined height, and then a suction pad (not shown) is passed through the through hole 12 of the upper die. The resin mold part 34 is inserted into the inside and is transferred to the next step in a state where the upper surface of the resin mold part 34 is suction-held. The pressing on the unnecessary resin 33 in the present invention means
This means that the unnecessary resin 33 is directly pressed.

In this embodiment, with the lead frame 31 on the mounting table 4 being sandwiched between the upper and lower molds 1 and 2, the mounting table 4 is moved downward with respect to the fixed table 3 so that the protrusions 5 are formed. Although the suspension lead 32 is cut by pressing it against the suspension lead 32, the present invention is not limited to this. As shown in FIG. 3, the lower mold 1 is fixed to the base and both side portions of the upper surface ( It is also possible to press and cut the suspension lead 32 by elevating the cut punch 13 having the protruding portion 12 on the left and right sides in the drawing with a hydraulic cylinder (not shown) or the like. Further, in this case, the cut punch 13 and the push-up punch 14 are integrally formed, and the hanging lead 3
The resin mold portion 34 may be pushed up while pressing and cutting 2.

Further, in this embodiment, the unnecessary resin 33
Although the case where the lead frame 31 attached to the lower surface of the suspension lead 32 is used has been described, the present invention is not limited to this, and the unnecessary resin 33 is attached to the lead frame attached to the upper surface of the lead frame 31. However, in this case, the protrusion 5 may be provided on the upper mold 2 side.

Further, in this embodiment, the lower mold 1 is fixed and the upper mold 2 is movable, but the lower mold may be movable and the upper mold 2 may be fixed. In addition, in the present embodiment, all the suspension leads 32 are simultaneously pressed and cut by the protrusions 5, but the present invention is not limited to this, and only the suspension leads 32 to which the unnecessary resin 33 adheres are pressed and cut. After that, even if the resin mold portion 34 is pushed up by the push-up punch 7, the effect of the present invention can be obtained.

Further, in this embodiment, the suspension lead 3 is used.
Although a mold is used for cutting 2, the mold is not limited to this, and a mold made of ceramic or the like may be used.

[Brief description of drawings]

FIG. 1 is a perspective view of essential parts showing a suspension lead forming apparatus used in a method for manufacturing an electronic component of the present invention.

FIG. 2 is an explanatory view illustrating a manner of cutting a suspension lead by a suspension lead molding apparatus used in the method for manufacturing an electronic component of the present invention.

FIG. 3 is a side view of essential parts showing a modified example of the suspension lead forming apparatus using the method for manufacturing an electronic component of the present invention.

FIG. 4 is an explanatory diagram illustrating a state in which unnecessary resin is attached to the lower surface of the suspension lead of a lead frame used when manufacturing an IC.

FIG. 5 is an explanatory diagram illustrating a state in which a resin mold portion is chipped when a suspension lead is cut by a conventional cutting method.

[Explanation of symbols]

 1 Lower mold 2 Upper mold 3 Fixing table 4 Mounting table 5 Projection part 6 Through hole 7 Push up punch 8 Slide shaft 9 Compression spring 10 Through hole 11 Through hole 12 Projection part 13 Cut punch 14 Push up punch 31 Lead frame 32 Suspension lead 33 Unnecessary resin 34 Resin mold part

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[Procedure amendment]

[Submission date] July 28, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (2)

[Claims] 1. An electronic device including a step of separating a resin mold part suspended from the suspension lead from the lead frame in a connected state with an unnecessary resin attached to the suspension lead formed on the lead frame using an upper mold and a lower mold. In the method of manufacturing a component, in a state in which one of the upper and lower molds is in contact with the facing surface of the suspension lead, the other is pressed toward the unnecessary resin,
A method of manufacturing an electronic component, comprising cutting the suspension lead. 2. The protrusion provided on the other of the upper and lower molds is pressed toward the unnecessary resin.
A method of manufacturing an electronic component as described in.