JPH07161858A - Lead protective structure of surface-mount semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the shortcircuit between the adjacent lead terminals and also, enable the replacement of a semiconductor device by fixing a protective plate of such a size that it can cover the lead terminals led out of a semiconductor device onto the semiconductor device so that external force does not act directly on the lead terminals of the semiconductor device. CONSTITUTION:A protective plate 3 of such a size as to cover lead terminals are fixed onto a surface-mount IC2. Therefore, the shoulder, at least, of the lead terminal of the surface-mount IC2 is covered with the protective plate 3, and external force never fall on the lead terminal directly. Moreover, the protective plate 3 is fixed onto the surface-mount IC2, using any of a binder, an adhesive tape, pressure sensitive adhesive an adhesive tape, etc., and the fixing means is selected properly, according to the fixing force required for the protective plate 3, whether or not there is necessity to remove the protective plate 3 for replacement, etc., of the surface-mount IC, etc. Hereby, the surface- mount IC can be removed by removing the protective plate 3 easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective structure for protecting leads of a surface mount semiconductor device, and is particularly suitable for application to a semiconductor device manufactured by a tape carrier method.

[0002]

2. Description of the Related Art A resin encapsulation in which a lead member is connected to a semiconductor chip incorporating an IC (semiconductor integrated circuit), an LSI (large-scale integrated circuit), etc., and the chip and a part of the lead are sealed with a resin body. Stop semiconductor devices have been conventionally known. In such a semiconductor device, a main surface which is an active region of a semiconductor chip is covered with an oxide film, a wiring made of an aluminum film is provided on the oxide film, and a CVD film is further formed on the wiring.
It is in a state of being covered with an insulating film by (vapor-phase chemical reaction deposition method) and a final protective film of a polyimide resin coating film, and the periphery of the semiconductor chip is sealed with a resin body (mainly epoxy resin). The leads are lead-bonded to the terminals of the wiring.

FIG. 4 shows a printed circuit board on which the semiconductor device thus sealed is surface-mounted. (A) of this figure
I sealed on the printed circuit board 100 with epoxy resin or the like
It is a top view in which C101 and IC102 and passive components such as resistors and capacitors are surface-mounted, and it can be seen that IC101 and 102 occupy a considerable area of the surface of the printed circuit board 100. Further, FIG. 2B is a side view of the printed circuit board 100, but the passive components are omitted.

As a method of assembling a resin semiconductor device,
A tape carrier method has been widely adopted for the purpose of simplifying the lead bonding process. This method uses a carrier tape in which frame holes are provided in a long insulating flexible tape and finger-shaped leads are provided in each frame hole as desired, and the peripheral electrodes of the semiconductor chip are opposed to the fingers. The semiconductor chip and the leads are partly sealed with a resin body, and the tape is cut to separate the individual semiconductor devices. The leads are formed in a desired shape in the frame holes by laminating a copper foil on an insulating flexible tape having the frame holes and etching the copper foil.

The semiconductor device thus assembled is
The semiconductor device can be made smaller than the conventional semiconductor device, and the chip can be directly attached to the substrate, so that the heat dissipation can be improved. Therefore, the mounting area can be reduced by mounting the semiconductor device manufactured by the tape carrier method on the printed circuit board. FIG. 5 shows a state in which the semiconductor device manufactured by this tape carrier method is surface-mounted on a printed circuit board. This figure shows an IC 110 manufactured by a tape carrier method on a printed circuit board 100, a resistor,
It is a top view in which passive components, such as a capacitor, are surface-mounted. The lead pitch of this IC110 is 0.5 mm
The pitch is 0.3 mm, and the total number of leads is 208 pins, for example.

[0006]

However, in the semiconductor device manufactured by the tape carrier method, since the leads are formed by etching as described above, since the leads are generally thin and soft, their mechanical strength is low. However, even if some external force is applied to the shoulder of the lead, there is a problem that the shoulder of the lead terminal 111 contacts the shoulder of the adjacent lead terminal 112 as shown in an enlarged view in FIG. It was

In order to solve this, as shown in FIG. 6, the IC 110 is conventionally molded with an insulating mold member. When the IC 110 is molded as described above, external force is not directly applied to the lead terminals, so that it is possible to prevent adjacent lead terminals from contacting each other, but since the IC 110 is molded during manufacturing, the IC 110 is replaced. Needless to say, when even one of the lead terminals of the IC 110 having a large number of lead terminals has a contact failure, it cannot be repaired, and the entire printed circuit board becomes a defective product. There was a problem that it would end up.

Therefore, it is an object of the present invention to provide a lead protection structure for a surface mount semiconductor device, which enables replacement of the semiconductor device and prevents external force from being directly applied to the lead terminals of the semiconductor device. .

[0009]

In order to solve the above-mentioned problems, the present invention has a protective plate fixed to the top of the semiconductor device, the protection plate having a size capable of at least covering the lead terminals drawn from the semiconductor device. It is a thing.

[0010]

According to the present invention, since the external force is not directly applied to the lead terminals by the protection plate fixed on the semiconductor device, it is possible to prevent accidents where adjacent lead terminals contact each other. Further, by removing the protective plate from the semiconductor device, the semiconductor device can be replaced or the lead terminal or the like can be soldered.

[0011]

FIG. 1 shows a first embodiment of the present invention. FIG. 1A is a top view in which the surface-mounted IC 2 manufactured by the tape carrier method and passive components such as resistors and capacitors are surface-mounted on the printed circuit board 1. The pitch of the leads of the surface mount IC 2 is, for example, 0.5 mm, the number of lead terminals is, for example, 208 pins, and the protective plate 3 having a size that covers the lead terminals is fixed on the surface mount IC 2. . FIG. 2B is a side view of a printed circuit board on which the surface mount IC 2 manufactured by the tape carrier method is surface mounted, and the passive components are omitted.

From this view (b), it can be understood that at least the shoulders of the lead terminals of the surface-mounting IC 2 are covered with the protective plate 3, and external force is not directly applied to the lead terminals. The protective plate 3 is fixed on the surface-mounted IC 2 using any one of an adhesive, an adhesive tape, an adhesive material, an adhesive tape, etc. The fixing means is selected such that the required fixing strength of the protective plate 3 and the surface are used. It should be decided as appropriate depending on whether it is necessary to remove the protective plate for replacement of the mounted IC. The protection plate 3 may be attached to the IC 2 before or after the surface mount IC is mounted on the substrate.

A second embodiment of the present invention is shown in FIG. FIG. 1A shows a surface mount IC 11 and a surface mount IC 12 manufactured by a tape carrier method on a printed circuit board 10, passive components such as resistors and capacitors, and other surface mount ICs.
FIG. 3 is a top view in which is surface-mounted. This surface mount IC
The lead pitch of 11, 11 is, for example, 0.3 mm, and the number of lead terminals is, for example, 208 pins. On the surface-mounting IC 11 and the surface-mounting IC 12, a single protective plate 13 having a size that covers at least the lead terminals is fixed in common. FIG. 1B is a side view of the printed circuit board 10 on which the surface-mounting IC 11 and the surface-mounting IC 12 manufactured by the tape carrier method are surface-mounted, and the passive components are omitted.

From this view (b), it can be understood that the lead terminals are covered with the protective plate 13 and the external force is not directly applied to the shoulders of the lead terminals of the surface-mounting IC 11 and the surface-mounting IC 12. The protective plate 13 is fixed on the surface-mounting IC 11 and the surface-mounting IC 12 by using any one of an adhesive, an adhesive tape, an adhesive material, an adhesive tape, and the like. Strength,
Protective plate 13 for surface mounting IC11, IC12 replacement, etc.
Make an appropriate decision according to whether or not it needs to be removed.

FIG. 3 shows a modification of the second embodiment of the present invention. This figure shows the surface mount IC 31 and the surface mount IC manufactured by the tape carrier method on the printed circuit board 10.
32, the surface mount IC 33, and a resistor (not shown),
It is a top view in which passive components, such as a capacitor, are surface-mounted. The pitch of the lead terminals of the surface mount ICs 31, IC 32, and IC 33 is, for example, 0.3 mm pitch or 0.5 mm, and each IC is provided with a large number of lead terminals. On the surface-mounting IC 31, the surface-mounting IC 32, and the surface-mounting IC 33, one protective plate 34 having a shape that covers at least the lead terminals thereof is commonly fixed.

With this protective plate 34, the surface mount IC 31,
It can be understood that the lead terminals of the IC32 and IC33 are covered and the external force is not directly applied to the shoulders of the lead terminals of the surface-mounting IC31, IC32, and IC33. This protective plate 3
4 is a surface mount IC31, IC32, IC33 using any one of an adhesive, an adhesive tape, an adhesive material, an adhesive tape, etc.
Although it is fixed on the upper side, the fixing means is appropriately selected depending on the required fixing strength of the protective plate 34 and whether or not the protective plate 34 needs to be removed for replacement of the surface mounting ICs 31, 32 and 33. To do so.

As shown in FIGS. 2 and 3, when a protective plate is provided commonly to adjacent semiconductor devices so as to protect the lead terminals of each semiconductor device, a protective plate is provided for each semiconductor device. The work can be greatly simplified compared to. The protective plate is usually formed by cutting a sheet of plastic or the like into a required shape. However, if the protective plate is made of a transparent sheet, it is convenient to understand the state under the protective plate. Also, the thickness of the protective plate may be selected in consideration of the material of the protective plate so as to satisfy the necessary fixing strength, but if it is thick, it may interfere with other components mounted on the printed circuit board. Therefore, it is desirable to set the thickness to the minimum necessary.

[0018]

Since the present invention is constructed as described above, it is possible to effectively protect the shoulder portion of the lead terminal of the surface mounted IC which has been conventionally exposed. Also, surface mounting I
Even when it is desired to remove C, the surface mounting IC can be easily removed by removing the protective plate by appropriately selecting the means for fixing the protective plate. Further, it is less laborious than the lead protection structure by molding, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a surface mount IC lead protection structure of the present invention.

FIG. 2 is a diagram showing a second embodiment of the surface mount IC lead protection structure of the present invention.

FIG. 3 is a diagram showing a modification of the second embodiment of the surface mount IC lead protection structure of the present invention.

FIG. 4 is a diagram in which a conventional surface mount IC is mounted on a printed circuit board.

FIG. 5 is a diagram in which a surface mount IC manufactured by a conventional tape carrier method is mounted on a printed circuit board.

FIG. 6 is a diagram showing a conventional surface mount IC lead protection structure.

[Explanation of symbols]

1, 10, 100 substrate 2, 11, 12, 31, 32, 33, 101, 102,
110 surface mount IC 3,13,34 protective plate 111,112 lead terminal 120 mold part

Claims (3)

[Claims] 1. In a semiconductor device surface-mounted on a substrate, an insulating protective plate having a size capable of covering at least leads extending from the periphery of the semiconductor device is fixed to the semiconductor device. Characteristic Lead protection structure for surface mount semiconductor devices. 2. An insulating protective plate, which comprises at least two semiconductor devices surface-mounted on a substrate, and has a size capable of covering at least the leads drawn from the periphery of the semiconductor device. A lead protection structure for a surface mount semiconductor device, which is commonly fixed on a semiconductor device. 3. The lead protection structure for a surface mount semiconductor device according to claim 1, wherein the insulating protection plate is made of a transparent sheet.