JPS623984B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a thin plate body that is closely attached to a base having heat dissipation fins, and a circuit mounted on the thin plate body is covered. Related to electronic devices.

BACKGROUND ART Nowadays, extremely sophisticated and complex functions are being required of electronic devices mounted on automobiles and the like or electronic devices for outdoor equipment. Such consumer electronic devices are subject to severe environmental conditions such as vibration, temperature changes, humidity, etc. in which they are installed. Under the above conditions, in order to downsize and increase the density of electronic devices and improve weather resistance, it is necessary to improve heat dissipation and airtightness.

[Conventional technology]

BACKGROUND ART Conventionally, as an electronic device that operates under the above-mentioned severe conditions, a device as shown in FIG. 1, for example, has been used for power transistors.
In FIG. 1, a power transistor device 1
1 includes a base 11 made of Kovar or the like, a silicon circuit chip 12, and a cap body 1 made of Kovar.
3. It is composed of a connector 14. The circuit chip 12 is die-bonded (Au-Su brazing) as shown at 17 on the base 11, and the cap body 13 is welded to the base as shown at 18. The connector 14 is hermetically sealed (glass sealed) in a hole provided in the base 11. The silicon circuit chip 12 is connected to a connector 14 by a connecting conductor 16.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional techniques cannot sufficiently meet the current demand for higher density devices. That is, in the prior art, the circuit chip 12
are brazed to the base 11 made of Kovar, but if the density is increased, more parts may be mounted on the base 11. However, as the number of components mounted increases, the amount of heat generated from the components also increases, and the temperature of the device itself increases.

Therefore, if brazing is used as a means of joining the base 11 and the chip 12 as in the past, the heat dissipation effect is small, and the electrical and mechanical properties of the mounted components deteriorate due to heat generation. .

In addition, since the back surface of the base 11 is flat as a whole, an effective area for heat dissipation is not secured, and when the density is increased, the temperature rise of the device cannot be prevented, resulting in the same characteristics as described above. is the cause of the decline.

Next, from the viewpoint of airtightness, when increasing the density, brazing, which is a conventional joining method shown in Fig.
7 and welding 18 have low melting points, so there is a risk that they will melt due to heat generation, making them susceptible to external temperature, humidity, etc.

Furthermore, conventionally, the cap body 13 was joined to the surface of the base 11 by welding 18, so the cap body 13 was removed and the chip 12 and connector 1
Even if you try to inspect or replace 4, the above welding 18
It took some time to melt the parts. As the density increases, the opportunities for maintenance and replacement of electronic devices increase proportionally, but maintenance and replacement is not easy with conventional technology.

As described above, the conventional technology has problems in that heat dissipation and airtightness deteriorate when the density is increased, and maintenance and replacement are not easy.

[Means to solve the problem]

The present invention aims to solve the above-mentioned problems and improve all of the heat dissipation, airtightness, and maintenance/replacement of high-density electronic devices. A thin plate body carrying circuit components is bonded to the surface of the base with a heat sink compound, and a through hole for inserting an external drawer connector is formed near the thin plate body on the surface of the base. The connector electrically connected to the circuit component is hermetically sealed on the inner wall of the through-hole, and a cover cap body that covers the thin plate body and the through-hole is attached to the surface of the base via a sealing member. An electronic device characterized in that it is screwed.

[Effect]

The device of the present invention has heat dissipation fins planted on the back surface of the base, and a thin plate body with circuit components bonded to the heat sink compound is mounted on the back surface of the base, and a through hole is formed and an external drawer connector is installed on the inner wall of the device. The hermetically sealed connection improves both heat dissipation and airtightness, and since the thin plate and the cap covering the through hole are screwed to the substrate surface, ease of maintenance and replacement is improved.

〔Example〕

Hereinafter, the present invention will be explained by way of examples with reference to the accompanying drawings.

FIG. 2 is a longitudinal sectional view of the device of the invention. The device shown in FIG. 2 consists of a base 21 made of a material such as molybdenum or Kovar having the same coefficient of thermal expansion as ceramics, a thin plate body 22 made of an insulating layer such as glass ceramics, and a circuit pattern conductive layer, and a base 21. Cap body 2 installed on top
3, and the base 21 is provided with heat dissipation fins 211 on its back surface and a through hole 212 (FIG. 4) for an external drawer connector near the thin plate body 22.

The base 21, the thin plate body 22, and the cap body 23 are formed of materials having substantially the same coefficient of thermal expansion, thereby avoiding the risk that they will be thermally destroyed due to fluctuations in heat generated from the outside or inside. Base 2
1, a plurality of thin heat dissipating fins 211 are formed in a downwardly protruding shape to enhance the heat dissipating effect as described later.

On the other hand, a thin plate body 22 on which a circuit component 26 is mounted is adhered to the surface of the base 21 with a heat sink compound 222 (FIG. 3), as will be described later. The circuit components 26 mounted on the thin plate body 22 are components constituting a desired electronic circuit, such as transistors, thyristors, and LSIs.

As shown in FIG. 3, the heat sink compound 222 for bonding the thin plate body 22 onto the base is
It surrounds the side and bottom surfaces of the thin plate body 22 and is interposed between the entire bottom surface of the thin plate body 22 and the surface of the base 21 over a wider area.

A recess 223 for mounting a circuit component is formed in the center of the upper surface of the thin plate body 22 bonded to the base with the heat sink compound, and circuit structure layers 221 are formed on both sides of the recess 223.

The circuit component 26 is placed in the recess 223 using the adhesive 2.
24. The circuit component 26 includes
Connection conductors 261 and 262 are provided on the surface opposite to the surface to be bonded to the thin plate body 22, and the connection conductors 26
1,262 are connected to the circuit configuration layer 221. Therefore, the heat generated in the circuit component 26 is transferred to the adhesive 224, the thin plate body 22, the heat sink compound 222, and the base 2 as shown by the arrow.
1 and the heat radiation fins 211 to the outside.

As a result, despite the high density of the device 2,
The heat dissipation effect is further enhanced than before.

As shown in FIG. 4, the external drawer connector through-hole 212 has an inner wall formed in a stepped shape, and a connector 25 having a shape corresponding to the inner wall is seated.
The connector 25 is composed of an insulating member 251 made of ceramic or plastic and a lead-out conductor 525, and is hermetically sealed to the stepped portion of the through hole 212 provided in the upper base 21 insulated with glass or the like. A lead-out conductor 252 that passes through an insulating member 251 forming the connector 25 projects downward toward the outside of the device so that it can be fitted into a mating connector, and also extends toward the inside of the device and connects it with solder 225. It is connected to the surface pattern 226 of the thin plate body 22 via the conductor 28.

Further, an enveloping cap body 23 is closely fixed to the surface of the base 21 with screws 27 via an O-ring 24 so as to completely cover the connector and circuit components 26 (FIG. 2).

The O-ring 24 is inserted into a rectangular groove 241 formed on the surface of the base 24, and enhances the sealing effect between the enveloping cap 23 and the base 21 to prevent dust from entering from outside the device. (Figure 2).

In addition, since the cap body 23 is attached to the base 21 with screws 27, it is easier to remove the circuit component 26 during maintenance and inspection compared to the conventional welding 18 (FIG. 1), and it is possible to remove the malfunctioning circuit component 26. 26 is easier and faster to replace.

The electronic device shown in FIG. 2 having the above configuration is manufactured by the following method. In this manufacturing method, first, a dielectric paste such as glass-based ceramics is printed on the flat surface of the base 21 provided with heat dissipation fins using a screen printing method. Form an insulating layer. Next, a conductive paste is printed on this insulating layer to form a circuit pattern conductive layer. When the circuit patterns cross, it is also possible to form a multilayer circuit structure layer by repeating the printing of the insulating layer and conductive layer. The thin plate body 22 made of an insulating layer and a conductive layer formed on the base 21 in this way is
After printing, it is dried and then fired and completed.

Next, the connector 25 created in advance is attached to the base 21.
It is inserted into a hole provided in the hole and hermetically sealed with glass-based ceramics or the like. next,
The circuit component 26 is mounted on the thin plate body 22 and soldered to complete the circuit unit on the base. Finally, use the O-ring to close the cap body 23.
is airtightly mounted on the base 21.

When the thin plate body is formed by printing as described above, the base and the thin plate body are constructed as an integrated body, so that the heat dissipation effect is improved.

〔Effect of the invention〕

According to the present invention, it is possible to improve the heat dissipation, airtightness, and maintainability of electronic devices used under harsh conditions, thereby realizing miniaturization and higher density of electronic devices. .

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a conventional electronic device, FIG. 2 is a sectional view showing the configuration of an electronic device as an embodiment of the present invention, and FIGS. It is a partial detailed view. 2... Electronic device, 21... Base, 211... Heat dissipation fin, 212... Through hole for external drawer connector, 22... Thin plate body, 221... Circuit configuration layer, 2
22...Heat sink compound, 23...Enveloping cap body, 24...O ring, 25...External drawer connector, 251...Insulating member, 252...
...Output conductor, 26...Circuit component, 27...Screw, 28...Connection conductor.

Claims (1)

[Claims] 1 A heat dissipation fin is formed on the back surface of the base, and a thin plate body carrying circuit components is bonded to the surface of the base with a heat sink compound, and an external drawer connector is inserted on the surface near the thin plate body. A through hole is formed in the inner wall of the through hole to seal and seal the connector electrically connected to the circuit component, and the base surface further covers the thin plate body and the through hole. An electronic device characterized in that a covering cap body is screwed through a sealing member.