JPH01291415A - Semiconductor device - Google Patents

Abstract

PURPOSE:To easily and effectively cope with high power noise by engaging varistor through-type capacitors with input/output terminals passing a shielding case, and electrically connecting the outer terminal of the capacitor to the case. CONSTITUTION:Varistor through-type capacitors 10 are respectively provided on the way of the lines of input terminal 12, output terminal 13 and ground terminal 14 of a semiconductor pressure sensor, and the outer terminal of the capacitor 10 is electrically connected to a shell 7 and a metal vessel 9 to become a shielding case. Accordingly, an IC pressure sensor element 1 is protected to an erroneous operation by the shell 7 and the vessel 9 against an electromagnetic wave directly invading through the air. A large power noise such as an ignition pulse or the like is protected by the capacitor and varistor functions of the capacitor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a semiconductor device in which a detection element and an amplifier circuit are arranged within a shield case.

[Prior art] In recent years, with the electronicization of automobiles, electromagnetic interference (EMI) of electronic devices has been increasing.
neti-c 1 interference) has become a problem. Therefore, in order to protect electronic equipment, such as a semiconductor pressure sensing element and an amplifier circuit that amplifies the output signal of the sensing element, from the electromagnetic environment, the sensing element and the amplifier circuit are covered with a metal container, or with an EMI filter. Protecting.

A device with such EMI countermeasures is disclosed in Japanese Utility Model Application Laid-Open No. 61-50240.

In this device, a detection element and an amplifier circuit are hermetically sealed in a metal container (shield case), and a through-type Contin 4 is fitted to the input/output terminals that are insulated and pass through the metal container. , the outer terminal of this capacitor is electrically connected to the metal container.

[Problems to be Solved by the Invention] However, although the device disclosed in the above publication is effective against electromagnetic waves propagating in the air, the device is effective against electromagnetic waves propagating in the air, but it is effective against ignition pulses from an automobile spark plug via a harness due to its noise. In order to prevent this, it was necessary to use a large-capacity feed-through capacitor. Furthermore, if a capacitor is installed separately from the feedthrough capacitor to prevent ignition pulses from entering through the harness, it will hinder miniaturization and cost reduction, and in particular, it will be difficult to make the detection element and amplifier circuit monolithic. It was difficult to mount a multilayer chip capacitor in such equipment.

An object of the present invention is to provide a semiconductor device that can easily and reliably take measures against high power noise such as ignition pulses input directly through a harness.

[Means for Solving the Problems] A semiconductor device in which a detection element and an amplifier circuit for amplifying an output signal of the detection element are arranged in a shield case, the semiconductor device being insulated by the shield case, and including the shield case. The gist of the present invention is a semiconductor device characterized in that a varistor feedthrough capacitor is fitted into a penetrating input/output terminal, and an outer terminal of the varistor feedthrough capacitor is electrically connected to a shield case.

[Operation: This varistor feedthrough capacitor eliminates high power noise such as ignition pulses that are input directly through the harness.

[Example] Hereinafter, an example in which the present invention is embodied in a semiconductor pressure sensor will be described with reference to the drawings.

As shown in FIG. 1, a monolithic IC sensor element 1
consists of a pressure detection element and an amplification temperature compensation circuit for amplifying and temperature compensating the output signal of the pressure detection element. More specifically, a plurality of piezoresistive layers are formed on a silicon diaphragm 2 made of single crystal silicon, and an amplification temperature compensation circuit is formed in a thick part around the diaphragm 2 using bipolar IC or MO8IC manufacturing technology. has been done. Then, the change in resistance value of the piezoresistive layer on the diaphragm 2 due to pressure is detected as an electrical signal,
The signal is amplified, temperature compensated, and output to the outside.

This IC sensor probe 1 is arranged on a stage 3 made of silicon or Pyrex glass (for example, Corning Co., Ltd. W size 7740), and the stage 3 is placed on a metal base 4. Further, a hermetic terminal 5 in which the outside of the conductor is insulated with an insulating material is supported by glass sealing on the metal base 4, and the input/output terminal and ground terminal of the IC sensor element 10 are bonded to the hermetic terminal 5. Electrical connection is made by wire 6. In addition, in Figure 1,
Only two hermetic terminals 5 for input and output terminals are shown, and the hermetic terminals for grounding and bonding wires are not shown.

A shell (metal container) 7 serving as a shield case is arranged on the upper surface of the metal base 4 so as to cover the IC sensor cable 1 and the like, and both 4 and 7 are hermetically joined by projection welding. The space sealed by the metal base 4 and the shell is used as the pressure reference chamber of the sensor.

Furthermore, communication holes 3a and 4''a are formed in the stage 3 and the metal base 4, respectively, and a conduit 8 is provided on the lower surface of the metal base 4, and the communication hole 3a is connected to the diaphragm 2.
, 4a, a measuring pressure is applied via conduit 8. A metal container 9 serving as a shield case is joined to the lower surface of the metal base 4 by welding. The penetration position of the three-wood hermetic terminal 5 with respect to the metal container 9 is as follows.
A varistor type feedthrough capacitor 10 is fitted respectively.

As shown in FIG. 2, this varistor type feedthrough capacitor 10 is made of a cylindrical member 11 having a protrusion 11a on the outer periphery of the lower end, and the cylindrical member 11 is made of sulfur titanate to rontium. Then, the opening 9al of the metal container 9: the cylindrical material 11
is inserted, and the hermetic terminal 5 is inserted through the inside of the cylindrical member 11, and the outer peripheral surface of the cylindrical member 11 and the opening 9a of the metal container 9, and the inner peripheral surface of the cylindrical member 11 and the hermetic terminal 5 are soldered. There is. That is, the input/output terminal and ground terminal of the semiconductor pressure sensor are insulated from the metal container 9 by the hermetic terminal 5, and the external terminal of the capacitor 10 is electrically connected to the metal container 9.

The equivalent circuit of this varistor conductive capacitor part is shown in the third diagram.
As shown in the figure. As shown in the figure, the input terminal 12, output terminal 13, and ground terminal 14 of the semiconductor pressure sensor each have a varistor type feedthrough capacitor 10 installed in the middle of the line.
The external terminal of the varistor type feedthrough capacitor 10 is electrically connected to a shelf and a metal container 9 serving as a shield case.

With this configuration, the IC pressure sensor element 1 is protected from malfunction by the shelf and the metal container 9 (shield case) against electromagnetic waves that directly enter through the air, and the wiring is protected through the air. For weak electromagnetic waves that enter the input/output terminals 12 and 13 from the cable (harness), use a varistor feedthrough capacitor 10.
IC pressure sensor cord 1 is protected by the capacitor function of , and high-power noise such as ignition pulses input via the wiring cable (harness) is protected by the capacitor function and varistor function of the varistor feedthrough capacitor 10. protected. More specifically, E
It was confirmed that the MI shield level was within 1% FS at an electric field strength of 100 V/m.

Furthermore, instead of providing a noise filter inside the shelf and metal container 9 (shield case) to protect from ignition pulses input through the harness,
Since the feed-through capacitor has a varistor function, there is no need to separately prepare a noise filter, making it possible to reduce the size and cost. In particular, high-power noise can be easily and reliably prevented without installing a stacked chip content, which is difficult to mount in a monolithic device like the semiconductor pressure sensor of this embodiment. can.

Note that the present invention is not limited to the above embodiments, but can be applied to the fourth embodiment.
As shown in the figure, the ground terminal 14 may be directly connected to the metal base 4 or the metal container 9.

In addition to the semiconductor pressure sensor, the present invention may be embodied in a semiconductor acceleration sensor υ, a sensor using an electromagnetic resistance element, and the like. That is, it can be applied to semiconductor devices that handle weak signals.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to exhibit an excellent effect of easily and reliably counteracting high-power noise such as ignition pulses input directly through the harness. .

[Brief Description of the Drawings] Fig. 1 is a cross-sectional view of a semiconductor pressure sensor that embodies the present invention, Fig. 2 is a cross-sectional view of a varistor feedthrough capacitor, Fig. 3 is an equivalent circuit diagram, FIG. 4 is a circuit diagram of another example. 1 is an IC sensor detection element, 7 is a shell as a shield case, 9 is a metal container as a shield case, 10 is a varistor feedthrough capacitor, 12 is an input terminal, and 13 is an output terminal.

Claims (1)

[Claims] 1. In a semiconductor device in which a detection element and an amplifier circuit for amplifying an output signal of the detection element are disposed in a shield case, an input/output terminal insulated from the shield case and passing through the shield case has a varistor property. A semiconductor device comprising a feedthrough capacitor fitted therein and an outer terminal of the varistor feedthrough capacitor electrically connected to a shield case.