JPH04329657A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a small-sized, low-cost semiconductor device that has a large electromagnetic shielding effect and has such a structure that it is easily mounted. CONSTITUTION:A shield plate 31 covers the surface of a semiconductor device 1 at a minimum distance from the device 1. The shield plate is kept at a predetermined potential to remove effects of external electromagnetic disturbance on the operation of the device, thus obtaining stable operation. The shield plate has electrical connection with specified electrodes 22 of a first lead frame. Therefore, the number of process steps is reduced in mounting devices on a wiring board.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a structure for shielding a semiconductor element from electromagnetic disturbance signals and a method for manufacturing the same.

0002

BACKGROUND OF THE INVENTION In recent years, electronic technology has made remarkable progress, and its application fields are expanding to both consumer and industrial fields, and it is being used in a variety of devices. In addition, the environments in which they are used vary; some environments contain electromagnetic disturbance signals that have an extremely negative effect on the operation of electronic equipment and the semiconductor devices that make up it; on the other hand, electronic equipment itself is the source of the disturbance. There are many cases where this is possible. One measure to prevent the influence of electromagnetic disturbance signals is to shield and protect the electronic equipment itself or each semiconductor device individually from electromagnetic disturbance signals using conductive materials.

[0003] Conventionally, this type of shield uses a structure different from that of the object to be shielded, and is generally attached together with the object to be shielded when mounted on electronic equipment. This will be explained with reference to FIG. FIG. 9 is an external perspective view showing the structure of a conventional semiconductor device, and FIG. 10 is a side sectional view showing the internal structure of the semiconductor device.

As shown in the figure, in the conventional semiconductor device, a semiconductor element 1 is mounted on a semiconductor element mounting part 2 of a lead frame, and an electrode body of the semiconductor element 1 is electrically connected to an electrode part 5 of the lead frame by a thin metal wire 3. After the electrical connections are made, a shield 9 made of a conductive material is enclosed in the envelope 4 and covered around it. This shielder 9 has the function of shielding electromagnetic disturbance signals only when a predetermined potential is applied to it, but with the above configuration, the shielder 9 is electrically insulated from both. ,
It does not function as the intended shield at all. In order to provide a predetermined potential, it is possible to selectively electrically connect a predetermined electrode body of the semiconductor element 1 and maintain the shield 9 at a predetermined potential.This is the simplest method, but it This is the most effective connection method because it minimizes the distance between the shield and the shield.

Specifically, when mounting a semiconductor device on a circuit board or the like, a predetermined electrode portion 5 of a lead frame and a shield electrode portion 10 are electrically connected using a metal brazing material or the like. The shield 9 is given the same potential as the predetermined electrode portion 5 to which it is connected, and fulfills its original function of shielding electromagnetic disturbance signals.

[0006]

[Problems to be Solved by the Invention] In such a conventional semiconductor device, in order to make the shield 9 function, electrical connection is required at the time of mounting, which increases the number of assembly steps and the number of parts. Furthermore, since the shielding device 9 is provided outside the envelope 4, it is difficult to miniaturize the device, making it unsuitable for high-density packaging. In addition, the semiconductor element 1
is separated from the shield 9 via the envelope 4, and the distance d' is regulated by the thickness of the envelope from the surface of the semiconductor element 1. In order to further enhance the effect, it is essential to make this distance d' as small as possible,
When the envelope thickness (distance d') becomes large, there is also the problem that a sufficient shielding effect against electromagnetic disturbance signals cannot be exhibited.

An object of the present invention is to solve the above-mentioned problems, and to provide a semiconductor device that has a simple mounting process, is inexpensive and small, and has a high shielding effect against electromagnetic disturbance signals, and a method for manufacturing the same. be.

[0008]

A semiconductor device according to a first aspect of the present invention includes a semiconductor element and a shielding plate that covers a major surface area of the semiconductor element, which are integrally enclosed in one envelope. A semiconductor device according to a second aspect of the invention is characterized in that, in the semiconductor device according to the first aspect, the shielding flat plate and a predetermined electrode body of the semiconductor element are electrically connected.

The method for manufacturing a semiconductor device according to claim 3 comprises:
The present invention is characterized in that a semiconductor element is mounted on a first lead frame, and a second lead frame having a shielding flat plate and the first lead frame are aligned and sealed with resin.

0010

[Operation] According to the structure of the present invention, since the semiconductor element and the shielding flat plate covering the main surface area of the semiconductor element are integrally formed inside the envelope, the shielding flat plate can be placed close to the semiconductor element. By keeping the shielding plate at a predetermined potential,
The influence of electromagnetic disturbance signals related to the operation of the semiconductor device is eliminated, and stable and good operation can be obtained.

[0011]

Embodiments [First Embodiment] A first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, and 4. FIG. 1 is an external perspective view showing the structure of a semiconductor device according to a first embodiment of the present invention, and FIG. 2 is a side sectional view showing the internal structure of the semiconductor device.

In this semiconductor device, a semiconductor element 1 is mounted on a semiconductor element mounting portion 2 of a first lead frame using a conductive adhesive or the like, and an electrode body of the semiconductor element 1 is attached to an electrode of the first lead frame using a thin metal wire 3. After making an electrical connection with the part 5, the second lead frame having the shielding flat plate (conductive material) 11 is integrally enclosed in an envelope 4 made of resin, and from each lead frame, the lower crosspiece part 7, the middle part Pier 6,
The upper crosspiece 13 (see FIGS. 3 and 4) is cut and removed to separate into individual pieces. Here, the envelope 4 is formed using a transfer molding method.

FIGS. 3 and 4 are perspective views showing the structure of the assembly process of the semiconductor device. The second lead frame faces the semiconductor element 1 mounted on the first lead frame so that the surface of the semiconductor element 1 is covered with a shielding flat plate 11, and the second lead frame is arranged in a direction opposite to the extending direction of the electrode portion 5 of the first lead frame. The lead frame is inserted into the mold so that the shielding plate electrode portion 12 is positioned, but this positioning is determined by guide pins protruding from the mold and provided on the lower crosspiece 7 and upper crosspiece 13 of each lead frame. This is done through the alignment holes 8, 14. Further, the second lead frame is subjected to a compression bending process in advance, and the tip portion including the shielding flat plate 11 is bent and shaped so as to be separated from the surface of the semiconductor element 1 by a predetermined distance d (FIG. 2). . However, the distance d must be the minimum in order to avoid contact with the thin metal wire 3 and to obtain a high shielding effect.

The semiconductor device constructed in this manner is mounted on a circuit board, a predetermined potential is applied to the shield plate 11, and it functions as a shield. Here, the shielding flat plate 11 is connected via the shielding flat plate electrode part 12 to the first lead frame electrode part 5 having the semiconductor element mounting part 2 on which the semiconductor element 1 is mounted. Therefore, there is a shielding flat plate maintained at a predetermined potential so as to sandwich and cover the semiconductor element 1 from the front and back, and the effect becomes even higher.

As described above, according to the first embodiment of the present invention, the shield plate 11 is integrally formed inside the envelope 4 of the semiconductor device, covers the entire surface area of the semiconductor element 1, and The influence of electromagnetic disturbance signals related to the operation of the semiconductor device is eliminated by the shielding plate 11, which is disposed at the minimum physically possible distance d from the surface of the shielding plate 11 and maintained at a predetermined potential. Good operation can be obtained.

[Second Embodiment] A second embodiment of the present invention will be described with reference to FIGS. 5, 6, 7, and 8. FIG. 5 is an external perspective view showing the structure of a semiconductor device according to a second embodiment of the present invention, and FIG. 6 is a side sectional view showing the internal structure of the semiconductor device.

Similar to the first embodiment, this semiconductor device has the following features.
It is made of the same parts and materials, and has the same effect in terms of its assembly method and structure for shielding electromagnetic disturbance signals. However, the difference from the first embodiment is that the second lead is already connected to the second lead in its structure. The shielding flat plate (conductive material) 31 of the frame is connected to the predetermined electrode part 22 of the first lead frame (the electrode part having the semiconductor element mounting part 21 on which the semiconductor element 1 is mounted) via the shielding flat plate electrode part 32 of the frame. ) is selectively electrically connected to the Points different from the first embodiment will be explained with reference to FIGS. 7 and 8.

FIGS. 7 and 8 are perspective views showing the structure of the assembly process of the semiconductor device. The arrangement state of each of the first and second lead frames is different from that in the first embodiment, and the electrode portion 32 of the second lead frame is positioned in a direction that matches the direction in which the electrode portion 22 of the first lead frame extends. Therefore, after the envelope 4 is formed, each of them overlaps. However, in this state, they only make surface contact, and in the remaining assembly process, after cutting and removing the lower crosspieces 24, 35 and middle crosspieces 23, 34 of the first and second lead frames, the outer Each electrode part 2 exposed from the enclosure 4
When surfaces 2 and 32 are subjected to surface treatment so as to be coated with metal brazing material, they will inevitably be electrically connected to each other. Additionally, this surface treatment has traditionally been carried out for the purpose of increasing product value, such as preventing oxidation of electrode members and improving brazing properties during mounting. It does not increase the Finally, the upper rail portions 25 and 36 of each lead frame are cut and separated into individual pieces. In addition, 26a and 26b are alignment holes of the first lead frame, 33 is an incomplete electrode, and 37a and 37
b is an alignment hole of the second lead frame.

As described above, according to the second embodiment of the present invention, it goes without saying that the same effects as the first embodiment can be obtained. Since the shielding flat plate 31 is selectively electrically connected to the predetermined electrode portion 22 of the first lead frame, there is no need to electrically connect these when mounting on a circuit board, etc., reducing the number of man-hours. Also possible.

Note that in each embodiment, the type of semiconductor device 1 is not limited in any way, but the invention can be applied to all semiconductor devices.

[0021]

Effects of the Invention According to the semiconductor device and its manufacturing method of the present invention, a shielding plate that covers the surface area of the semiconductor element and is maintained at a predetermined potential is placed close to the semiconductor element, and By integrally forming the device, the mounting process can be simplified, the device can have an inexpensive and compact structure, it can also have a high shielding effect against electromagnetic disturbance signals, and stable and good operation can be obtained.

[Brief explanation of drawings]

FIG. 1 is an external perspective view showing the structure of a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a side cross-sectional view showing the internal structure of the semiconductor device.

FIG. 3 is a perspective view showing the configuration of an assembly process of the semiconductor device.

FIG. 4 is a perspective view showing the configuration of an assembly process of the semiconductor device.

FIG. 5 is an external perspective view showing the structure of a semiconductor device according to a second embodiment of the invention.

FIG. 6 is a side cross-sectional view showing the internal structure of the semiconductor device.

FIG. 7 is a perspective view showing the configuration of an assembly process of the semiconductor device.

FIG. 8 is a perspective view showing the configuration of an assembly process of the semiconductor device.

FIG. 9 is an external perspective view showing the structure of a conventional semiconductor device.

FIG. 10 is a side cross-sectional view showing the internal structure of the semiconductor device.

[Explanation of symbols]

1 Semiconductor element 2 First lead frame semiconductor element mounting section 3
Fine metal wire 4 Envelope 5 First lead frame electrode part

Claims (3)

[Claims] 1. A semiconductor device in which a semiconductor element and a shielding plate covering a major surface area of the semiconductor element are integrally enclosed in one envelope. 2. The semiconductor device according to claim 1, wherein the shielding flat plate and a predetermined electrode body of the semiconductor element are electrically connected. 3. A method for manufacturing a semiconductor device in which a semiconductor element is encapsulated with resin, the semiconductor element being mounted on a first lead frame, a second lead frame having a shielding flat plate and the first lead. A method of manufacturing a semiconductor device, which comprises aligning a frame with a frame and sealing the semiconductor device with a resin.