JP3266138B2 - Microwave integrated circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave integrated circuit (hereinafter referred to as a microwave IC), and more particularly, to a microwave integrated circuit having a plurality of high-frequency circuits mounted in a package.
Regarding C.

[0002]

2. Description of the Related Art FIG. 6 is a perspective view showing a structure of a conventional microwave IC before a metal cap is attached. FIG. 7 is a cross-sectional view showing a structure of a conventional microwave IC after a metal cap is attached.

In FIG. 6, reference numeral 1 denotes a metal carrier on which a plurality of high-frequency components such as a monolithic IC and a semiconductor bare chip are mounted (hereinafter referred to as a monolithic IC as a representative of the high-frequency components), and which has a heat radiation function of these monolithic ICs. Reference numeral 2 denotes a plurality of dielectric substrates using a ceramic material, 3 denotes a plurality of monolithic ICs having a high-frequency circuit function such as an amplifier and a mixer, and 4 denotes a metal carrier 1 which is hermetically sealed with a sealing glass or the like. The plurality of metal pins 5 are through holes through which the metal pins 4 pass through the metal carrier 1.

[0004] The dielectric substrate 2 is electrically connected to a plurality of monolithic ICs 3 mounted on the metal carrier 1 and microstrip lines or the like on the dielectric substrate 2 using bonding wires to form a high-frequency circuit. (Not shown).

As the material of the dielectric substrate 2, ceramic materials such as alumina, aluminum nitride, and glass ceramics and organic / resin materials such as fluororesin are mainly used.

[0006] The ceramic material has a drawback that it is difficult to form a complicated shape because the shape of the ceramic material is roughly determined mainly at the time of firing and the detailed shape processing is performed by cutting. On the other hand, organic / resin-based materials are easier to cut and drill than ceramic-based materials, but have the drawback of permeating and absorbing moisture because they are organic materials. Further, there is a disadvantage that the heat resistance temperature is low.

For this reason, in a conventional microwave IC, a ceramic-based material is used as the material of the dielectric substrate 2 and a plurality of dielectric substrates having a simple shape such as a rectangle as shown in FIG. It was arranged around IC3.

Further, as shown in FIG.
A metal cap 7 with a partition wall for covering the entire monolithic IC 3 is attached to the upper portion with a conductive adhesive to provide an electromagnetic shield between the high-frequency circuits.

Further, the metal cap 6 covering the whole of the metal cap 7 with the partition wall is welded to the metal carrier 1 and is attached to the airtight shield.

[0010]

In the conventional microwave IC described above, since a plurality of circuit functions are provided in one package, there are many connection points between a plurality of monolithic ICs 3 and a large number of dielectric substrates 2 are formed. Necessary and complicated in shape.

For this reason, the dielectric substrate using a ceramic material has a problem that it takes a long time to manufacture and the productivity is low.

On the other hand, it is conceivable to use the above-mentioned relatively easy-to-process organic / resin-based material as the dielectric substrate, but the heat resistance of the organic substrate is at most 200 to 300 ° C.
Therefore, a highly airtight means such as welding cannot be used for joining with the metal cap 6 and the metal carrier 1.
It is inevitable to use bonding with a conductive adhesive.

For this reason, it is impossible to obtain high hermetic sealing of the space in the package.

As described above, in the structure of the conventional microwave IC, it has been difficult to achieve both reduction in productivity and cost and securing of reliability by hermetic sealing.

[0015]

In order to solve the above-mentioned problems, a microwave integrated circuit according to the present invention has a dielectric substrate for transmitting a high frequency signal in a microwave band, and the dielectric substrate and the dielectric A metal carrier for mounting a high-frequency component mounted in a cavity hole formed by cutting a substrate, a first metal cap having a partition wall mounted on an upper portion of the dielectric substrate, and the first metal cap And a second metal cap that covers the second metal cap.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The mounting structure of a microwave IC according to the present invention will be described with reference to the drawings.

FIG. 1 is an exploded perspective view showing the structure of a microwave IC package. FIG. 2 is an exploded perspective view showing the structure of the metal carrier 1 and the dielectric substrate 10 of the microwave IC package shown in FIG. FIG.
FIG. 2 is a perspective view showing a structure of a metal cap 11 with a partition wall. FIG. 4 is a diagram showing a cross-sectional view of the microwave IC. FIG. 5 is a cross-sectional view showing each of the metal cap 1, the metal cap with partition wall 11, the monolithic IC 3, the dielectric substrate 10, and the metal carrier 1 of FIG.

In FIG. 1, 1 is a metal carrier, 3 is a monolithic IC, 4 is a metal pin, 5 is a through hole, 6 is a metal cap, 10 is a dielectric substrate, and 11 is a metal cap with a partition wall.

The metal carrier 1 is a metal carrier, on which a dielectric substrate 10 and a monolithic IC 3 are mounted using a conductive adhesive.

Note that the surface of the metal carrier 1 has a structure without protrusions for attaching the dielectric substrate 10 and the monolithic IC 3 with a conductive adhesive such as an epoxy resin material. However, the projection is a projection made intentionally, and does not include a projection due to unintended irregularities or roughness based on a material manufacturing process.

The through holes 5 provided at a plurality of locations inside the metal carrier 1 are holes through which metal pins 4 connecting the upper and lower surfaces of the metal carrier 1 pass, as shown in FIGS. The metal pins 4 are fixed by filling the metal sealing glass 8 in the through holes 5. The sealing glass 8 fills a gap between the inner wall of the through hole 5 and the metal pin 4 and hermetically seals it. With such a structure, the metal pins 4 are inserted between the upper and lower sides of the metal carrier 1 to eliminate the gas flow through the through holes 5.

The dielectric substrate 10, like the conventional dielectric substrate 2, is used for connecting a plurality of high-frequency signals contained in a microwave IC package and for forming a passive circuit. However, as shown in FIG. 2, the dielectric substrate 10 of the present invention is formed of a single dielectric substrate, unlike the conventional dielectric substrate 2 formed of a plurality of substrates. In addition, a structure in which a plurality of cavity holes 14 are provided in a portion where a plurality of monolithic ICs 3 are mounted.

As a material of the dielectric substrate 10, for example, an organic substrate material such as Teflon glass, polyimide, fluororesin, ABS resin, and epoxy resin is used. For this reason, since complicated shape processing can be performed on one substrate, a structure in which a cavity hole 14 is formed by hollowing out a portion of the monolithic IC 3 is also possible.

Further, as shown in FIG. 2, the back surface of the dielectric substrate 10 is mainly a ground conductor, and the microstrip conductor 21 is formed on the front surface.
A high-frequency signal between C3 can be transmitted through a high-frequency transmission line such as a microstrip line.

Next, the dielectric substrate 10 and the monolithic IC
3 are joined to the metal carrier 1 by a conductive adhesive 13 as shown in FIG.

The monolithic IC 3 and the dielectric substrate 1
The microstrip line on 0 is connected by a bonding wire (not shown). Further, the dielectric substrate 1
In order to apply high frequency input / output and bias (DC current) between the microstrip line on 0 and the outside of the package,
The microstrip conductor 21 on the substrate and the metal pin 4 are connected by a bonding wire (not shown).

As shown in FIGS. 2, 4, and 5, between different high-frequency circuits arranged at adjacent positions on the dielectric substrate 10, there are provided conductive holes 12 arranged in a row through the substrate.
And a ground conductor 22.

As shown in FIG. 3, the metal cap 11 with a partition wall is a cavity-shaped metal cap which escapes the area where the monolithic IC 3 is mounted. As shown in FIG. 5, the mounting of the metal cap 11 with a partition wall on the dielectric substrate 10 is performed by connecting the lower part of the metal cap 11 with the partition wall and the ground conductor on the surface of the dielectric substrate 10 to a conductive adhesive 1
3 are joined.

The metal cap 6 is directly welded to the metal carrier 1 without passing through the dielectric substrate 10. As described above, since the metal cap 6 is directly joined to the metal carrier 1 by welding, the joint is hermetically sealed, and the inside of the package is protected from intrusion of moisture from the outside.

Here, as shown in FIG. 4, the spacing a between the rows of the conductive holes 12 of the dielectric substrate 10 and the inner width b of the partition of the metal cap with partition wall 11 both use a high-frequency circuit. The frequency is made smaller than half the wavelength of the electromagnetic wave. The conduction hole 12 has an effect that an electromagnetic wave of a used frequency does not propagate in a waveguide mode in an inner space of the metal cap 11 with the partition wall, the conduction hole 12 and the metal carrier 1.

The metal pin 4 is supplied with a DC bias current from the outside, and the internal monolithic IC operates. Further, an intermediate frequency signal and a high frequency signal are also input and output via the metal pin 4.

[0032]

As described above, in the microwave IC of the present invention, the dielectric substrate is connected to one sheet,
Since the work of joining the substrate to the metal carrier only needs to be done once,
Cost reduction and productivity improvement can be brought about.

In addition, the propagation of unnecessary electromagnetic waves in the waveguide mode can be prevented in the space in the package formed by the conductive hole provided in the dielectric substrate, the partition wall of the metal cap with the partition wall, and the metal carrier. As a result, unnecessary feedback or unnecessary oscillation can be prevented from being applied to the high-frequency amplifier.

The partition wall of the metal cap and the conduction hole are
Electromagnetic isolation between different adjacent circuits arranged on a monolithic IC can also be taken.

In addition, hermetic sealing requires sufficient characteristics to protect the semiconductor chip from moisture (MIL-STD).
-883). Although the metal cap of the present invention is not sufficiently hermetically sealed only by enclosing the cap with the partition wall and the dielectric substrate with the conductive adhesive, the metal cap is welded to the metal carrier, so that the package structure has a high airtightness. There is an effect that a hermetic seal can be obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a microwave IC package according to the present invention.

FIG. 2 is an exploded perspective view showing a structure of a metal carrier 1 and a dielectric substrate 10 of FIG.

FIG. 3 is a perspective view showing a structure of a metal cap with a partition wall 11 of FIG.

FIG. 4 is a diagram showing a cross-sectional view of the microwave IC of FIG. 1;

5 is a sectional view showing each of the metal cap 6, the metal cap with partition wall 11, the monolithic IC 3, the dielectric substrate 10, and the metal carrier 1 of FIG.

FIG. 6 is an exploded perspective view of a conventional microwave IC package before a metal cap is mounted.

FIG. 7 is a cross-sectional view of a package after mounting a metal cap of a conventional microwave IC.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 metal carrier 2 dielectric substrate 3 monolithic IC 4 metal pin 5 through hole 6 metal cap 7 metal cap with partition 8 sealing glass 10 dielectric substrate 11 metal cap with partition 12 conductive hole 13 conductive adhesive 14 cavity hole

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-11-135661 (JP, A) JP-A-2000-188497 (JP, A) JP-A-10-41421 (JP, A) JP-A-10-92963 (JP, A) JP-A-10-189869 (JP, A) JP-A-6-181266 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 23/00-23 / 10 H01L 23/16-23/26

Claims (8)

(57) [Claims] 1. A metal carrier for mounting a dielectric substrate for transmitting a microwave band high frequency signal, and a high frequency component mounted in a cavity hole formed by cutting the dielectric substrate and the dielectric substrate on the dielectric substrate. And a first metal cap having a partition wall attached to an upper part of the dielectric substrate, and a second metal cap covering the first metal cap. 2. The microwave integrated circuit according to claim 1, wherein the metal carrier is attached to the dielectric substrate and the high-frequency component using a conductive adhesive. 3. The microwave integrated circuit according to claim 1, wherein said dielectric substrate and said first metal cap are attached using a conductive adhesive. 4. The microwave integrated circuit according to claim 1, wherein the dielectric substrate has a plurality of conductive holes arranged in a row between the adjacent high-frequency components. 5. The microwave integrated circuit according to claim 4, wherein said conductive hole is formed in a ground conductor on said dielectric substrate. 6. An interval between each row of said conductive holes is determined by a frequency used.
Claim, characterized in that one half wavelength or less 4 or 5
The microwave integrated circuit as described in the above. 7. The microwave integrated circuit according to claim 1, wherein an inner width of the partition of the first metal cap is equal to or less than a half wavelength of a used frequency. 8. The microwave integrated circuit according to claim 1, wherein the attachment between the second metal cap and the metal carrier is hermetically sealed by welding.