JPS58102545A - Hybrid integrated circuit - Google Patents

Abstract

PURPOSE:To obtain a structure resistant to external noises with high reliability, by forming a part or the whole of a hybrid IC in a structure coated with conductive metal. CONSTITUTION:On an alumina substrate 10 wherein a circuit is formed of a thin film of a thick film, electronic parts 11 of a transistor, an IC, etc. are mounted and soldered to the circuit, and a Cu foil 13 is adhered on the back surface of the substrate 10. A lead frame 12 is connected to the circuit at one side end part of the substrate 10, and the entire body is protected by coating with the resin 14 such as epoxy resin. When the magnetic field is applied to the Cu foil 13 and inversed at a high frequency, the electromagnetic induction from a noise source which exists in the right direction, because of being erased by the magnetic field generated by the eddy current on the Cu foil 13 generated according to the Lenz's law, is not passed through the Cu foil, and accordingly the influence given to the hybrid IC is cut off or reduced. In a static aspect, the hybrid IC is shielded by the Cu foil 13 and becomes difficult to be subjected to noise hindrances.

Description

[Detailed description of the invention] The present invention relates to the structure of hybrid integrated circuits.

Conventionally, hybrid integrated circuits are manufactured by attaching electrical components and external lead frames to an alumina substrate on which a circuit is formed using a thin film or thick film, and then protecting the entire board with epoxy resin.
- A common structure is to attach the device to a protrusion or to place it in a molded case and pot it with silicone resin.

When the above-described conventional hybrid integrated circuit is placed near an electric component such as a transformer that generates a high electric field, it is easily affected by the electric field generated by the electric component and may malfunction. That is, it has the disadvantage of being weak against external electric field noise.

Furthermore, when a conventional hybrid integrated circuit is incorporated into a device, the above-mentioned drawbacks impose severe constraints on power distribution, making it difficult to downsize the device.

SUMMARY OF THE INVENTION An object of the present invention is to overcome the above-mentioned drawbacks of the prior art and to provide a hybrid integrated circuit tube that is less susceptible to external noise.

The hybrid integrated circuit of the present invention achieves the above object by covering all or part of its periphery with a conductive metal film or foil.

In order to eliminate the influence of external noise, electromagnetic shielding and electrostatic shielding must generally be performed.

Since electromagnetic shielding generally requires a sufficiently thick shield using a magnetic material with high magnetic permeability, it is difficult and uneconomical to apply it to minute objects such as hybrid integrated circuits. on the other hand,
The hybrid integrated circuit #i generally does not malfunction due to induction of low frequency noise, but many malfunction due to high frequency noise.

The present invention has been made with attention to this point, and the method of simply covering with a conductive metal film or foil does not only provide electrostatic conduction but also generates an electromagnetic shielding effect and reduces external noise. This is to prevent the effects of

Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view showing one embodiment of the present invention, which is applied to a single in-line hybrid integrated circuit.

That is, a transistor is formed on an alumina substrate 10 on which a circuit is formed using a thin film or a thick film.

Electrical components 11f such as ICs are mounted, soldered to circuits at required points, and copper foil 13 is pasted on the back surface of the board 1O. Further, the lead frame 12 is connected to the required portions of the circuit at one end of the substrate 10. The entire structure is coated with epoxy resin 14. In this example, the electromagnetic induction from the noise source present in the right direction in the figure is caused by the eddy current on the copper foil 13 caused by Lenz's law when the magnetic flux penetrates the copper foil 13 and reverses at a high frequency. Because it is canceled by the magnetic flux generated by the magnetic flux, it does not penetrate the steel foil and has no effect on the hybrid integrated circuit.
Reduced. Of course, it is electrostatically shielded by the copper foil lO. In other words, there is an effect that the hybrid integrated circuit is less susceptible to noise interference.

FIG. 2 shows an example in which the present invention is applied to a dual-line hybrid integrated circuit. In this case, the lead frame 21 is led out from both ends of the substrate 21. The substrate 21 is covered with a molded case 22 and potted with a resin 23 such as silicon, as in the conventional case, but a copper plating film 24 is formed on the inner surface of the case 220 by electroless plating. This case also has the same effect as described above.

Instead of the above-mentioned copper foil or copper plating film, a metal with high electrical conductivity such as aluminum may be used. The copper foil shown in Figure 1111 is good even if it is placed on the outside of the epoxy resin.
The plating shown in the figure may be applied to the outside of the case or to the entire case. Of course, it is desirable to surround the entire circuit.

As described above, in the present invention, since the hybrid integrated circuit has a structure in which part or all of it is covered with conductive metal,
This has the effect of making the circuit resistant to external noise and highly reliable, as it is shielded from high-frequency interference noise that could cause circuit malfunction.

41111F+0Simplified JIIIL 1111 is a sectional view showing one embodiment of the present invention, No. 2II
FIG. 2 is a sectional view showing an embodiment of the central office 110;

In WJ, 10.21... alumina substrate, 11.
- Electrical component, 12... Lead frame, 13- Copper foil,
! 4--Epoxy resin, 22--Case, 23-Silicon resin, 24--Steel plating film.

Agent: Patent attorney: 1) Sou Toshi Figure 1 Figure 2

Claims (1)

[Claims] A hybrid integrated circuit that is entirely or partially covered with a conductive metal film or foil is considered to be 1%.