JPH06318597A - Semiconductor device - Google Patents

Abstract

PURPOSE:To realize high speed operation of a circuit, by a method wherein the influence of external noise is reduced by forming one or many layers of conductive films covering a greater part of an element, on the uppermost layer of a semiconductor device, and constituting electrostatic shielding, internal noise is reduced by adding a smoothing capacitor, and the conductive layers are used as power supply wirings. CONSTITUTION:A conductive film 7 and a second conductive film 8 are formed on the uppermost layer part of a substrate 1, and connected with a power supply side lead frame 5 and a ground side lead frame 6. These conductive films are used as a power supply smoothing capacitor, an electrostatic shielding plate, and an electromagnetic shielding plate. By electrically connecting the conductive films with a circuit, the conductive films can be used as the power supply wiring, which stably supply power and reduce the influence of external noise upon internal circuits. When a single layer of the conductive film 7 is formed, it has the effect of electrostatic shielding and that of electromagnetic shielding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to noise prevention and high speed operation technology.

[0002]

2. Description of the Related Art FIG. 2 shows a schematic sectional view of a conventional semiconductor device. In the conventional semiconductor device, as shown in FIG. 2, the semiconductor substrate 1 is protected from mechanical shock and humidity by being enclosed with a protective film 3 and a resin package 4. The power supply side lead frame 5 and the ground side lead frame 6 directly supply power to the semiconductor circuit on the semiconductor substrate 1 via the bonding wires 2. However, in general, when a semiconductor device is used, it is exposed to electrical noise, magnetic noise, and power source noise generated by circuits around the semiconductor device,
The user of the semiconductor device inserts a bypass capacitor in the power input section of the semiconductor device, or provides electrostatic shielding,
In addition, it is necessary to devise the circuit layout to reduce the noise generated by the peripheral circuits, and sufficient knowledge and experience are required.

[0003]

In the conventional semiconductor device, although the electric circuit on the semiconductor substrate is physically protected by using a resin or the like, it is in an electrically exposed state and is not exposed from the outside. There was a problem that there is a high possibility of malfunction due to electrical noise and magnetic noise. Further, in a semiconductor device including a large number of output transistors, the power consumed internally is large, so that the power supply is insufficient inside the semiconductor device, which may cause a malfunction due to noise from the power supply. It was

An object of the present invention is to provide a semiconductor device capable of reducing external noise such as electric noise and magnetic noise generated by a circuit around the semiconductor device, and external noise such as power supply noise, or internal noise, and contributing to high-speed operation of the circuit. To do.

[0005]

The semiconductor device of the present invention comprises:
Conductive film on the protective film to protect the semiconductor circuit 1
By forming a layer or a multi-layered structure and connecting the conductive film to a power source, a ground, or both, electrostatic shielding, electromagnetic shielding or a power smoothing capacitor, power wiring,
Alternatively, it is configured to include and use these.

[0006]

The present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view for explaining an embodiment of the present invention, FIG. 1A is a cross-sectional view of one embodiment in which one conductive film is formed, and FIG. FIG. 1C is a sectional view of another embodiment in which layers are formed, and FIG. 1C is a sectional view of a third embodiment in which power is directly supplied to a circuit that consumes a large amount of power.

First, the first embodiment will be described. Figure 1
As shown in (a), a conductive film 7 is formed on the semiconductor substrate 1 and the protective film 3, and the conductive film is connected to the ground-side lead frame 6 via a bonding wire. or,
The conductive film 7 can be directly connected to the ground pad of the power source of the semiconductor substrate. Thereby, the conductive film 7 can have an effect of shielding the semiconductor substrate 1.

Next, a second embodiment will be described with reference to FIG. In FIG. 1B, the conductive film has two layers,
In a cross-sectional view when used as a smoothing capacitor simultaneously with shielding, a second conductive film 8 insulated from 7 is formed on the conductive film 7 in FIG. It is connected to the lead frame 5 on the power source side through. Since the conductive film 7 and the second conductive film 8 are insulated from each other and have a potential between the power supply and the ground, they operate as a smoothing capacitor. Further, it has a shielding effect at the same time as FIG.

Next, a third embodiment will be described with reference to FIG. FIG. 1C shows an example in which power is directly supplied from the conductive films 7 and 8 to a circuit that consumes a large amount of power, such as the output transistors, in the second embodiment. Power to 11,
The second conductive film 8 is connected to the output transistor source 10 through the conductive film 7. Here, 9 is an output transistor gate. When the above power supply is supplied to a circuit that consumes a large amount of power, the parasitic resistance of the power supply wiring can be reduced and the effect of the smoothing capacitor can be directly reflected in the circuit that consumes a large amount of power. A semiconductor device that does In this embodiment, the first
This embodiment has the features of both the embodiment and the second embodiment.

Although not described in the above description of the embodiments, it is desirable to form a protective film on the uppermost layer from the viewpoint of moisture resistance.

[0011]

As described above, according to the present invention, one or two layers of conductive film are formed on a semiconductor circuit, and when this is used as an electrostatic shield or in the case of two layers, it is used as a power supply smoothing capacitor. In addition, since it is possible to reduce electric noise, magnetic noise, and noise from the power supply, it is possible to realize a semiconductor device that is not easily affected by noise.

Further, when the conductive film is used as the power supply wiring, the parasitic resistance of the power supply wiring can be reduced, so that a faster semiconductor device can be realized.

[Brief description of drawings]

1A and 1B are cross-sectional views of a semiconductor device for explaining an embodiment of the present invention. FIG. 1A is a cross-sectional view of an embodiment in which one conductive film is formed, and FIG. FIG. 1C is a cross-sectional view of another embodiment in which two layers of films are formed, and FIG. 1C is a cross-sectional view of a third embodiment in which a power is directly supplied to a circuit in which a conductive film has two layers and consumes a large amount of power.

FIG. 2 is a cross-sectional view of a conventional semiconductor device.

[Explanation of symbols]

 1 Semiconductor Substrate 2 Bonding Wire 3 Semiconductor Circuit and Protective Film 4 Resin Package 5 Power Lead Frame 6 Ground Lead Frame 7 Conductive Film 8 Second Conductive Film 9 Output Transistor Gate 10 Output Transistor Source 11 Output Transistor Transistor drain

Claims (1)

[Claims] 1. In a semiconductor device in which a desired element is formed on the surface of a semiconductor substrate and an electric circuit is constituted by metal wiring, a conductive film covering most of the element is formed on the uppermost layer of the semiconductor device.
A semiconductor device having a layered or multilayered structure, which is used as an electrostatic shield, an electromagnetic shield, a power supply smoothing capacitor, a power supply wiring, or a combination thereof by holding the conductive film at a constant potential.