JPH02102594A - Hybrid integrated circuit substrate - Google Patents

Abstract

PURPOSE:To prevent an external lead-out electrode from being shortcircuited by a solder penetrating into the gap between an insulating substrate and a printed substrate by a method wherein one of the external lead-out electrodes, which are composed of a part of a film conductor formed on the substrate, formed on the side opposed to the printed substrate is covered with an insulating film. CONSTITUTION:A hybrid integrated circuit substrate is mounted on a printed substrate 11 on which a conductor pattern has been formed, and the hybrid integrated circuit substrate is connected to the conductor pattern 11 with solder 13 at a through-hole provided to the side of the hybrid substrate. In this case, as a film conductor 3 constituting the external lead-out electrode is covered with an insulating film 6 at the rear side of the hybrid integrated circuit substrate opposed to the printed substrate 11, the solder 13 is prevented from penetrating into the gap between the printed substrate 11 and the hybrid semiconductor integrated substrate, and even if penetrates, the solder 13 is prevented from touching the conductor 3 on the rear side. By this setup, even if the space between the adjacent film conductors is very small, a short circuit between them can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hybrid integrated circuit board, and more particularly to a leadless hybrid integrated circuit board that can be directly soldered to a printed circuit board or the like.

[Conventional technology]

In recent years, as electrical equipment has become lighter and thinner, hybrid integrated circuit devices used in these equipment have also been required to be smaller and thinner. For this reason, the method of mounting a hybrid integrated circuit board has changed from a structure in which a lead frame for external terminals is attached to the board and mounted on a printed circuit board, etc., to a structure in which electrode lands on the hybrid integrated circuit board are directly mounted on a printed circuit board, etc. A so-called leadless structure is used.

For example, FIG. 4 shows an example, in which the surface of the insulating substrate 1,
The film conductors 2 and 3 formed on the back surface constitute a required circuit together with the resistor 5, and are electrically connected to each other through a through hole 4 provided at the end of the insulating substrate 1. The front and back surfaces of the insulating substrate 1 are each covered with an insulating film 6.
At a location near the end, each film conductor 2.3 is exposed except for the insulating film 6, and is configured as an external lead electrode.

The hybrid integrated circuit board constructed in this way is constructed by placing the hybrid integrated circuit board on the conductor pattern 12 provided on the printed circuit board 11 as shown in FIG. Mounting is performed by connecting the membrane conductors 2 and 3 and through holes 4 of the .

[Problem to be solved by the invention]

In the conventional hybrid integrated circuit board described above, the film conductor 3 exposed on the back surface of the insulating substrate 1 is placed close to the surface of the printed circuit board 11, so the solder 13 for mounting is applied to the insulating substrate. There is a problem in that the gap between the film conductor 1 and the printed circuit board 11 expands laterally due to capillary action, shorting out adjacent film conductors 3. In particular, as the arrangement pitch of membrane conductors 3 as external lead-out electrodes becomes smaller due to the recent increase in the number of pins in hybrid integrated circuits, the number of solder short circuits between adjacent membrane conductors 3 increases significantly, and the assembly yield of electronic devices decreases. and cause a decrease in reliability.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hybrid integrated circuit board that prevents short circuits caused by solder between adjacent electrode lands.

[Means to solve the problem]

In the hybrid integrated circuit board of the present invention, the external lead electrodes formed on the surface facing the printed circuit board among the external lead electrodes formed of part of the film conductor on the front and back surfaces of the insulating substrate, respectively, are connected to the insulating film. The structure is coated with

[Effect]

In the above configuration, the external lead electrode formed on the surface of the insulating board facing the mounting printed circuit board is covered with an insulating film, so that the external lead electrode is covered by the solder that enters between the insulating board and the printed circuit board. This can prevent short circuits.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention.

'I7 of alumina ceramic with a thickness of 1.0-! Film conductors 2 and 3 are formed in required patterns on the front and back surfaces of the A-edge substrate 1, respectively, and a thick film resistor 5 is arranged to form a thick film circuit. These film conductors 2 and 3 on the front and back surfaces are electrically connected to each other through a through hole 4 with a diameter of 0.3 mm provided on the side surface of the insulating substrate 1.

The film conductors 2, 3 and the thick film resistor 5 are covered with an insulating film 6 made of an insulating cover glass, and the insulating film 6 is partially removed at the ends thereof to form external extraction electrodes. There is. However, here, the insulating substrate 1
Although part of the insulating film 6 on the side surface and the front surface is removed to expose the film conductor 2 and the through hole 4, the insulating film 6 on the back side is not removed, and the film conductor 3 on the back side is exposed. It is configured so that it does not.

The hybrid integrated circuit board thus constructed is placed on a printed circuit board 11 on which a conductive pattern 12 is formed as shown in FIG. Connected. In this configuration, on the back side of the hybrid integrated circuit board facing the printed circuit board 11, the film conductor 3 constituting the external lead electrode is covered with the insulating film 6, so that the solder 13 is connected to the printed circuit board 11. It does not enter the gap, and even if it does, it does not come into contact with the membrane conductor 3 on the back surface. Thereby, even if the distance between adjacent film conductors 3 is minute, short circuits between them can be prevented.

FIG. 3 is a longitudinal sectional view of another embodiment of the present invention, in which the same or equivalent parts as in FIG. 1 are given the same reference numerals. In this embodiment, film conductors 2.3 formed on the front and back surfaces of an insulating substrate 1 are connected to each other through a through hole 4 or a through hole 7, and these are covered with an insulating solder resist film 6A. . In this case as well, a portion of the resist film 6A is removed from the side surface and the front surface, but the resist film 6A is not removed from the back surface, and the film conductor 3 serving as the external extraction electrode is covered.

In this configuration as well, short circuits between adjacent film conductors due to solder can be prevented as in FIGS. 1 and 2.

〔Effect of the invention〕

As explained above, the present invention covers the external lead electrode on the side facing the printed circuit board with an insulating film, among the external lead electrodes formed of a part of the film conductor provided on the insulated substrate. When mounting a hybrid integrated circuit board on a printed circuit board, it is possible to prevent solder from entering between the insulating board and the printed circuit board and short-circuiting adjacent external lead-out electrodes, making it possible to obtain a highly reliable mounting structure. can.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing the mounting state, FIG. 3 is a longitudinal sectional view of another embodiment of the invention, and FIG. 4 is a conventional hybrid FIG. 5 is a vertical cross-sectional view of the integrated circuit board showing a conventional mounting state. DESCRIPTION OF SYMBOLS 1... Insulating substrate, 2... Surface film conductor, 3... Back film conductor, 4... Through hole, 5... Thick film resistor, 6
...Insulating film, 6A...Solder resist, 7...Through hole, 11...Printed circuit board, 12...Conductor pattern, 13...Solder. 2nd 3rd

Claims (1)

[Claims] 1. In a hybrid integrated circuit board in which part of the film conductor formed on the front and back surfaces of an insulating substrate is configured as an external lead-out electrode, and this external lead-out electrode is soldered to a printed circuit board for mounting, the surface facing the printed board What is claimed is: 1. A hybrid integrated circuit board, characterized in that an external lead-out electrode configured in the following manner is covered with an insulating film.