JP2534841B2 - Envelope for 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 an envelope of a microwave integrated circuit which accommodates a semiconductor device used in a microwave band frequency.

[0002]

2. Description of the Related Art As a semiconductor device used in a microwave band frequency, a monolithic microwave integrated circuit (hereinafter referred to as a monolithic microwave integrated circuit in which a matching circuit, a bias circuit, or a semiconductor element such as an FET is integrated on a semi-insulating semiconductor substrate such as GaAs. M
MIC) is attracting attention because of its small size, light weight, and low price during mass production. From the viewpoint of reliability, this MMIC needs to be incorporated in an airtight envelope. Generally, as an envelope used in a microwave circuit, an input / output lead portion forms a microstrip line and a side wall portion. Many have a three-layer structure. However, this envelope has the advantage that the parasitic reactance in the high frequency input / output section is small, but has the disadvantage of being extremely expensive. Therefore, as a low-cost package, there is a package currently widely used in digital integrated circuits and the like.
A structure incorporating a C chip is shown in FIG.

3 (a) is a plan view, FIG. 3 (b) is a rear view, FIG. 3 (c) is a sectional view taken along line AA ', and FIG. 3 (d) is a side view. A plurality of connecting terminal portions are symmetrically provided in the peripheral portion of the ceramic substrate 1, and the side wall of the ceramic substrate 1 has the same shape as the outer shape of the ceramic substrate 1 so as to surround the central portion thereof. 2 is provided. Further, a lid 3 for closing the upper portion of the ceramic side wall 2 is provided. Here, in the central portion of the ceramic substrate 1, the ground conductor 4
Is provided, and the MMIC 5 is mounted on the ground conductor 4.

Further, the high frequency input / output terminal and the bias terminal of the MMIC 5 are connected to a predetermined input / output terminal 7 of a plurality of connection terminal portions provided on the surface of the ceramic substrate 1 by a bonding wire 6, respectively. Meanwhile, MM
The ground electrode of the IC 5 is connected to the ground conductor 4 by a through hole or the like in the MMIC 5, and the ground conductor 4 is connected by a bonding wire 6 to a predetermined ground terminal 8 on the surface of the ceramic substrate.

Here, the input / output terminal 7 and the grounding terminal 8 of the envelope are sandwiched by the metal film 9 and the grounding metal film 10 provided around the ceramic substrate 1, respectively.
Is connected to an external connection terminal 11 and an external ground terminal 12 provided on the back surface of the.

When the MMIC 5 is incorporated in the envelope as described above, the bonding wire 6, the ground terminal 8 and the grounding metal film 10 are provided between the ground electrode of the MMIC 5 and the external ground terminal 12 of the envelope. Since the inductance is connected, the ground inductance becomes large, especially MMIC.
In the case where 5 is an amplifier using an FET, there is a drawback that the gain is lowered.

Further, since the bonding wire 6, the input / output terminal 7 and the metal film 9 are interposed between the high frequency input / output terminal or the bias terminal of the MMIC 5 and the external connection terminal 11, the inductance is increased similarly to the above, and thus the MM is obtained.
There is a drawback that the gain of the IC is lowered. Further, when the envelope is connected to an external circuit, in the high frequency input / output unit, the connection terminal 7 and the metal film 9 and the ground terminal 8 and the ground metal film 10 have a large interval, so that the connection terminal 7 and the metal film 9 are parasitic. Since the impedances are connected to each other, a path having a predetermined impedance is not formed, and the impedance at the input / output portion of the envelope greatly changes, which deteriorates the characteristics of the MMIC.

[0008]

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned drawbacks, and improves the MMI by improving the conductor and the ground conductor on the dielectric substrate of the envelope for a microwave integrated circuit.
An object of the present invention is to provide an envelope for a microwave integrated circuit that does not deteriorate the characteristics of C.

[0009]

According to the present invention, a dielectric substrate, at least one input / output terminal provided in the peripheral portion on the surface of the dielectric substrate, and a constant number along the input / output terminal are provided. A grounding conductor, which is surrounded by a distance and is provided on the entire surface of the dielectric substrate, on which a microwave integrated circuit is mounted and to which a ground electrode of the mounted microwave integrated circuit is connected, and the grounding conductor. A connector for connecting the input / output unit of the microwave integrated circuit attached to the conductor and the input / output terminal, an external connection terminal and an external ground terminal provided in the peripheral portion on the back surface of the dielectric substrate, and the external connection. Connection conductors for connecting the terminals and external ground terminals to the input / output terminals and the ground conductor, respectively, and a side wall portion provided on the peripheral portion on the surface of the dielectric substrate so as to surround the central portion of the dielectric substrate. When It is characterized in that it has and a lid for closing the upper portion of the side wall portion.

[0010]

In the microwave integrated circuit enclosure required as described above, it is possible to suppress the change in impedance at the input / output portion of the enclosure and prevent the deterioration of the characteristics of the MMIC in the enclosure.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram in which an MMIC is attached to an envelope according to the present invention, FIG. 1 (a) is a plan view, FIG. 1 (b) is a rear view,
FIG. 1 (c) is a sectional view taken along the line AA ', and FIG. 1 (d) is a side view.

In FIG. 1, input / output terminals 7 are symmetrically provided on the periphery of the ceramic substrate 1, and the ground conductor 4 is surrounded along the input / output terminal 7 with a certain distance so that the ceramic substrate 1 is surrounded. Is provided on the entire surface of. That is, the gap 13 is formed between the input / output terminal 7 and the ground conductor 4.

An MMIC 5 is attached to the ground conductor 4, and a high frequency input / output terminal and a bias terminal of the MMIC 5 are connected to an input / output terminal 7 on the ceramic substrate 1 by a bonding wire 6, respectively. On the other hand, the ground electrode of the MMIC 5 is connected to the ground conductor 4 by the MMIC 5
It is directly connected by a through hole inside.

The input / output terminals 7 and the ground conductor 4 of the envelope are connected to the external connection terminal 11 and the external ground terminal 12 provided on the back surface of the ceramic substrate 1 through the metal film 9 and the ground metal film 10, respectively. It is connected. further,
A ceramic side wall 2 having the same shape as the outer shape of the ceramic substrate 1 is provided in the peripheral portion of the ceramic substrate 1 so as to surround the central portion thereof. Further, a lid 3 for closing the upper portion of the ceramic side wall 2 is provided.

It is considered that the input / output terminal 7 constitutes one transmission line (coplanar line) by the gap 13 and the ground conductor 4, and the wider the input / output terminal 7 is,
Further, the smaller the width of the gap (the smaller the distance between the input / output terminal 7 and the ground conductor 4), the smaller the impedance.

According to the above structure, since the ground conductor 4 is formed over almost the entire area of the ceramic substrate 1, the ground inductance can be made sufficiently small. Also, MM
For each input / output terminal 7 of the IC 5, the width of each input / output terminal 7 and the width of the gap 13 are optimally selected, so that the input / output portion (coplanar line, metal film 9 and grounding metal film 10) of the envelope is selected. , The external connection terminal 11 and the external ground terminal 12 are included), and the performance of the MMIC 5 can be prevented from decreasing.

2 (a) to 2 (c) show another embodiment in which the shape of each input / output terminal 7 forming the coplanar line of the MMIC 5 is changed in the envelope described in the embodiment of FIG. Here is an example. FIG. 2A shows a structure in which the plurality of input / output terminals 7 are formed such that the width of the portion to which the bonding wire 6 is connected is wider than the width of the portion to which the metal film 9 is connected. That is, the shape of the input / output terminal 7 becomes large, and the peripheral length of each input / output terminal 7 and the gap 13 becomes long.

With such a structure, the capacitance between the input / output terminal 7 and the ground conductor 4 can be increased. Therefore, M due to the inductance of the bonding wire 6, the input / output terminal 7 and the metal film 9
A change in the characteristic impedance of the MIC 5 can be prevented by increasing the capacitance.

Even if the distance between the input / output terminal 7 and the ground conductor 4 is narrowed as shown in FIG. 2B, the same effect as that of the embodiment shown in FIG. 2A can be obtained.

Further, FIG. 2C shows that the facing portions of the respective input / output terminals 7 and the ground conductor 4 are formed in a comb shape and are combined with each other. With such a structure, the peripheral length of the gap 13 between the input / output terminal 7 and the ground conductor 4 becomes long, and the equivalent capacitance between the input / output terminal 7 and the ground conductor 4 is shown in FIG. 2 and the embodiment shown in FIG. 2 (b), the characteristic impedance of the MMIC 5 can be prevented from changing, and each input / output unit can be made small, so that the envelope can be reduced. It can be miniaturized.

[0021]

According to the present invention, on the dielectric substrate in the envelope for a microwave integrated circuit, the ground conductor is surrounded along the input / output terminals with a certain distance, and the entire surface of the dielectric substrate is covered. By forming the structure in the microwave integrated circuit package, it is possible to suppress the impedance variation caused by the generation of parasitic impedance in the input / output part of the microwave integrated circuit package and to bring out the original performance of the microwave integrated circuit. An enclosure can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the present invention.

FIG. 3 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Dielectric substrate 4 ... Ground conductor 7 ... Input / output terminal 8 ... Ground terminal 9 ... Metal film 10 ... Metal film for ground 11 ... External connection terminal 12 ... External ground terminal

Claims (3)

(57) [Claims] 1. A dielectric substrate, and at least one input / output terminal provided in a peripheral portion on a surface of the dielectric substrate,
It is provided along the input / output terminal with a certain distance and is provided on the entire surface of the dielectric substrate. Further, the microwave integrated circuit is mounted and the ground electrode of the mounted microwave integrated circuit is A grounding conductor to be connected, a connecting body for connecting the input / output terminal of the microwave integrated circuit attached to the grounding conductor and the input / output terminal, and an external connecting terminal provided in the peripheral portion on the back surface of the dielectric substrate. And an external ground terminal, connection conductors for connecting the external connection terminal and the external ground terminal to the input / output terminal and the ground conductor, respectively, and a central portion of the dielectric substrate on a peripheral portion on a surface of the dielectric substrate. An envelope for a microwave integrated circuit, comprising: a side wall portion provided so as to surround the side wall; and a lid closing an upper portion of the side wall portion. 2. The envelope for a microwave integrated circuit according to claim 1, wherein the facing portions of the plurality of input / output terminals and the ground conductor each have a comb shape and are combined with each other. 3. The microwave integrated circuit envelope according to claim 1, wherein a width of a portion of the plurality of input / output terminals for connecting the connecting body is wider than a width of a portion for connecting the connecting conductor. vessel.