JP2001274285A - Lead terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide lead terminals of a high frequency circuit component whereby its parasitic inductances in its earth portion are reduced to obtain good high frequency characteristics, and the spatial coupling generated between its input/output lead terminals is prevented to avoid such unstable states as oscillation. SOLUTION: The lead terminals of a high frequency circuit component 3 provided on a board 1 having a metallic earth plate 2 as its rear metal comprise a ground lead terminal 21 and input/output lead terminals 22, 23. The ground lead terminal 21 has such a shape as to be storable in the surface of a through hole 11 provided in the board 1 and connects the high frequency circuit component 3 with the metallic earth plate 2 by being inserted into the through hole 11. The input/output lead terminals 22, 23 are provided on both sides of the ground led terminal 21 and connect the high frequency circuit component 3 respectively with input/output-oriented conductors 12, 13 provided on the board 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead terminal of a high-frequency circuit component, and more particularly to a method of obtaining a good high-frequency characteristic by reducing an inductance parasitic to a ground portion, and a spatial coupling between input and output lead terminals. The present invention relates to a lead terminal for preventing an unstable state such as oscillation by preventing the above.

[0002]

2. Description of the Related Art For example, due to a shortage of conventionally used frequency resources, in recent years, microwave and millimeter wave band signals which have not been conventionally used have been used for wireless communication and the like. Therefore, application of a system for handling signals in the microwave band or the like is greatly expected.

[0003] Compared with other low frequency signals, microwave band and millimeter wave band signals have a large spatial attenuation and a short radio transmission distance. It has an advantage that it can be used without overlapping (return use of frequency). In addition, since wideband transmission is possible using a microwave band or a millimeter wave band, a high-speed wireless LAN system or a cordless camera system suitable for transmitting large-capacity information at high speed using such a high-frequency band. Practical application of image monitors, image monitor systems, high-speed wireless network systems, and the like is proceeding at a rapid pace.

In realizing a system that handles signals in the high frequency band as described above, high frequency circuit components such as a microwave integrated circuit (MIC) are generally used. Here, as the MIC, a hybrid MIC (H) formed by forming a transmission path on a dielectric substrate made of, for example, alumina and mounting chip components (for example, active elements such as transistors) on the transmission path is used.
MIC (Hybrid MIC) or, for example, gallium arsenide (GaAs)
s) and a monolithic MIC (MMIC: Monolithic MIC) composed of batch production of passive elements and active elements such as transistors on a semiconductor substrate made of silicon (Si).
Etc. are known.

A specific example of a conventional mounting structure of a high-frequency circuit component will be described below. FIG. 5 shows a configuration example of a high frequency integrated circuit unit in a microwave band or a millimeter wave band as an example of a mounting structure of a conventional high frequency circuit component. In this unit, a plurality of dielectric substrates 41 to 44 are provided side by side in a cavity portion of a metal housing 31.
One or a plurality of high-frequency circuit components 45 and 46 are mounted thereon. As the high-frequency circuit component, for example, a package MMIC chip 45 or MMIC chip 46 is mounted.

Although not shown, each dielectric substrate 4
As a method of connecting the signal lines 1 to 44, for example, a method of electrically connecting by wire bonding using a thin metal wire is used. In addition, connectors 32 connected to signal lines and grounds provided on dielectric substrates 41 to 44 are provided on both side walls of metal casing 31, respectively.
a, 32b are provided, and the connectors 32a, 3b
It is configured to be connected to an external circuit via 2b.

Although not shown, there are various known methods for mounting high-frequency circuit components. For example, as a method for mounting the MMIC chip 46, wire bonding using fine metal wires, There are methods such as bonding and flip chip bonding for directly connecting using metal bumps. For example, as a method for mounting the package MMIC chip 45, in addition to the method described above, a conductive adhesive or solder may be used. There is a way to connect using the attachment. In addition, when wire bonding is used, a reduction in loss is generally achieved by bonding a plurality of wires in parallel.

FIG. 6 is an external perspective view of a unit in which one package MMIC chip 54 is mounted on one dielectric substrate 53. FIG. 7 is a side sectional view of a main part of the unit shown in FIG. 6, and this section is a section at the center of the package MMIC chip 54.
In this unit, Kovar (Fe
-Ni-Co alloy), etc., and a conductive metal substrate 52 is fixed with screws, and a dielectric substrate 53 is joined on the metal substrate 52 by brazing or soldering using gold tin (AuSn) or the like. A package MMIC chip 54 having, for example, a low-noise amplifier or a high-output amplifier is mounted on the dielectric substrate 53.

On the surface of the dielectric substrate 53 are formed microstrip lines 61 and 62 for input and output and ground patterns 63 and 64 for ground (for grounding), and a solid ground 67 is formed on the back surface. ing. The ground patterns 63 and 64 formed on the front surface of the dielectric substrate 53 and the solid ground 67 formed on the back surface
Through holes 65 and 6 provided in the dielectric substrate 53
6 are connected by embedding a conductor.

The package MMIC chip 54 has input / output lead terminals (input / output lead terminals) 71,
72 and ground lead terminals (ground lead terminals) 73 and 74 are provided. Each of the input / output lead terminals 71 and 72 is electrically connected to each of the microstrip lines 61 and 62 formed on the dielectric substrate 53 by a conductive adhesive or the like. Reference numeral 74 is electrically connected to each of the ground patterns 63 and 64 formed on the dielectric substrate 53.

[0011]

However, in the conventional mounting structure of high-frequency circuit components as shown in FIG. 6, for example, a ground portion (for example, the above-described ground) provided on the upper surface (front surface) of the dielectric substrate 53 is provided. Lead terminal 73,
74 and the above-mentioned ground patterns 63 and 64) are connected to the solid ground 67 on the back surface through the through holes 65 and 66, so that an inductance component of the through holes 65 and 66 is generated, and the package MMIC is formed.
There is a problem that the chip 54 cannot be satisfactorily grounded at a high frequency. For this reason, for example, the amplification factor of the amplifier provided in the package MMIC chip 54 may be reduced.

As a countermeasure for solving the above-mentioned problem, although not shown, for example, a package MMIC is used.
A capacitor is mounted between each of the ground lead terminals 73 and 74 of the chip 54 and each of the through holes 65 and 66, and a series resonance by the inductance component of each capacitor and the inductance component of each through hole 65 and 66 is performed. Ground patterns 63 and 64 formed on the front surface of the dielectric substrate 53 and a solid ground 6 formed on the back surface.
7 can be short-circuited at high frequency. However, in such a countermeasure method, short-circuiting occurs only in a limited frequency band near the resonance frequency, and also near the resonance frequency, the series resistance of the through holes 65 and 66, the loss resistance of the capacitor, and the like are reduced. Due to the existence, there is a problem that the effect of short circuit cannot be sufficiently obtained, and good high-frequency grounding cannot be realized.

In the conventional mounting structure of high-frequency circuit components as shown in FIG. 6, for example, the input / output lead terminals 71 and 72 of the package MMIC chip 54 are spatially connected to each other as shown in FIG. For example, ground lead terminals 73 and 74 from an output lead terminal (for example, the input / output lead terminal 72) to an input lead terminal (for example, the input / output lead terminal 71) in the millimeter wave band because of the possible structure.
There is a problem that spatial coupling is generated by jumping over the signal and signal feedback may occur.

For this reason, for example, the package MM
When the IC chip 54 includes an amplifier having a large amplification factor, there is a problem that an unstable state such as oscillation may occur at a frequency with a large feedback amount. Here, FIG. 8 shows an example of the characteristic of the feedback amount with respect to the frequency. The horizontal axis of the graph in FIG. 8 shows the frequency (GHz), and the vertical axis shows the feedback amount (dB).
Is shown. In the example shown in the figure, an unstable state such as oscillation occurs at 33 GHz.

An unconditional stability condition (for example, a condition for preventing oscillation even if any passive circuit is connected before and after) in a two-terminal circuit is generally expressed by an equation using an S parameter and a stability coefficient K of the circuit. It is shown as 1. As shown in Equation 1, for example, when the gain (S21) is large and the feedback amount (S12) is large, the circuit becomes extremely unstable.

[0016]

(Equation 1)

As described above, the conventional method of mounting high-frequency circuit components or the physical structure of the high-frequency circuit components may cause extremely poor high-frequency characteristics.
For example, in the worst case, there is a serious problem that high-frequency characteristics as originally designed cannot be obtained, for example, oscillation at an unnecessary frequency occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and has as its object to provide a lead terminal of a high-frequency circuit component capable of obtaining good high-frequency characteristics. For example, it is possible to obtain a good high-frequency characteristic by reducing an inductance parasitic to a ground portion, and to prevent an unstable state such as oscillation by preventing a spatial coupling between input and output lead terminals. An object of the present invention is to provide a lead terminal of a high-frequency circuit component that can be used.

[0019]

In order to achieve the above object, in a lead terminal according to the present invention, a lead terminal of a high-frequency circuit component provided on a substrate having a metal ground plate on the back surface is provided on the substrate. A ground lead terminal which is inserted into the through-hole and connects the high-frequency circuit component and the metal ground plate and has a shape that fits within the plane of the through-hole; and a high-frequency circuit component and a board disposed on both sides of the ground lead terminal, respectively. And an input / output lead terminal for connecting to an input / output conductor provided in the above.

Accordingly, in the ground lead terminal having the above-described structure, the parasitic inductance at the ground portion can be made extremely small. Therefore, for example, even in an ultra-high frequency band such as a microwave band or a millimeter wave band, High-frequency grounding of the high-frequency circuit component can be reliably performed, and thereby good high-frequency characteristics can be obtained. Also,
For this reason, for example, it is possible to prevent the amplification factor of the amplifier provided in the package MMIC chip or the like from being reduced due to a grounding defect.

In addition, in the input / output lead terminal having the above structure, the spatial coupling between the input / output lead terminals can be achieved even in an ultra-high frequency band such as a microwave band or a millimeter wave band. Since this can be prevented by the ground lead terminal, an unstable state such as oscillation of the high-frequency circuit component can be avoided, and thereby good high-frequency characteristics can be obtained.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of a unit mounted with a package MMIC chip 3 having lead terminals according to one embodiment of the present invention. FIG. 2 is a side sectional view of a main part of the unit shown in FIG. 1, and this section is a section at the center of the package MMIC chip 3. FIG. 3 is a bottom view of the package MMIC chip 3 shown in FIG.

In this unit, a package MMIC chip 3 composed of, for example, a low noise amplifier is mounted on the surface of a ceramic substrate 1 which is a dielectric substrate. The ceramic substrate 1 is placed on a Kovar (Fe—Ni—Co alloy) plate 2 that is a good conductive metal substrate, and the Kovar plate 2 is brazed or soldered using gold tin (AuSn) or the like. And are integrated. In addition,
The relative permittivity of the ceramic substrate 1 is, for example, 10.0,
The thickness is, for example, 0.25 mm.

The Kovar plate 2 is placed on a metal housing 4 constituting a unit of this embodiment (for example, a high frequency integrated circuit unit for a microwave band or a millimeter wave band) and, for example, four screws 5a to 5d. And is fixedly fixed to the metal housing 4. Specifically, four screw through holes 14
a to 14d are provided on the Kovar plate 2,
Four screw taps 15a to 15d are provided on the upper surface of the metal housing 4, and the screws 5a to 5d are fixed to the screw taps 15a to 15d through the screw through holes 14a to 14d, so that the Kovar plate 2 and the metal housing are connected. 4 are fixed.

Microstrip lines 12 and 13 for input and output are formed on the front surface (upper surface) of the ceramic substrate 1, and a solid ground (not shown) is formed on the back surface (lower surface). The solid earth formed on the back surface of the ceramic substrate 1 is joined to the Kovar plate 2 provided on the back surface as described above. The ceramic substrate 1 includes, for example, a package MMIC chip 3
(In this example, the package MMIC)
A through hole 11 through which a ground lead terminal 21 described later is penetrated is provided at a position directly below the chip 3).

The package MMIC chip 3 includes:
One ground lead terminal (ground lead terminal) 21 is provided on the bottom surface, and two input / output lead terminals (input / output lead terminals) 22 and 23 are provided on both sides of the ground lead terminal 21. ing.

Here, the ground lead terminal 21 has, for example, a thickness substantially equal to the thickness of the ceramic substrate 1 (in this example, a thickness slightly larger than the thickness of the ceramic substrate 1) and is provided on the ceramic substrate 1. Through hole 11
Is formed of a rectangular parallelepiped metal piece having a shape that fits within the plane. The ground lead terminal 21 protrudes downward from the package MMIC chip 3 by the thickness of the ceramic substrate 1 as compared with the input / output lead terminals 22 and 23 on both sides thereof, for example, as shown in FIG. I have.

The ground lead terminal 21 of the present embodiment having the above-described configuration is inserted into the through-hole 11 provided in the ceramic substrate 1 so that the package MMIC chip 3
(For example, a conductor portion for ground in the package MMIC chip 3) and the Kovar plate 2 are connected. The electrical connection between the ground lead terminal 21 and the Kovar plate 2 is performed by, for example, applying solder, cream solder, a conductive adhesive, or the like to the through-hole 11 provided in the ceramic substrate 1, and performing the connection. The processing is performed, for example, after the ceramic substrate 1 and the Kovar plate 2 are joined and integrated.

The input / output lead terminals 22 and 23 are
As described above, it is composed of, for example, metal terminals arranged on both sides of the ground lead terminal 21, and each of the package MMIC chips 3 (for example, the package MMI)
It has a function of connecting input / output conductor portions in the C chip 3) to input / output microstrip lines 12 and 13 provided on the surface of the ceramic substrate 1. Specifically, in this example, one input / output lead terminal 22 is electrically connected to one microstrip line 12 by a conductive adhesive or the like, and similarly, the other input / output lead terminal 23 is connected to the other input / output lead terminal 23. Are electrically connected to the microstrip line 13.

As described above, the package MMIC of this embodiment
In the lead terminals (ground terminal 21 and input / output lead terminals 22 and 23) of the chip 3, for example, the ground lead terminal 21 is directly grounded to the Kovar plate 2, and a pair of conductor patterns sandwiching the ceramic substrate 1 is formed. Therefore, the inductance parasitic to the ground portion can be significantly reduced, for example, as compared with the related art. For this reason, in the lead terminal of this example, the package MMI is used even in an ultra-high frequency band such as a microwave band or a millimeter wave band.
The high frequency grounding of the C chip 3 can be reliably performed, and thereby, a good high frequency characteristic can be obtained. Also,
For this reason, for example, the package MMIC chip 3
It is also possible to prevent the amplification factor of the amplifier provided in the device from being lowered due to the grounding failure.

The package MMIC chip 3 of this embodiment
For example, since the ground lead terminal 21 has a three-dimensional shape that completely separates the input / output terminals 22 and 33 from each other, for example, an ultra-high frequency band such as a microwave band or a millimeter wave band is used. In this case, the spatial coupling between the input / output lead terminals 22 and 23 can be reduced. For this reason, in the lead terminal of this example, it is possible to avoid an unstable state in which, for example, the amplifier provided in the package MMIC chip 3 abnormally oscillates at an unnecessary frequency. High frequency characteristics can be obtained.

The package MMIC chip 3 of this embodiment
For example, the ground terminals 63 and 64 and the through holes 65 and 6 as shown in FIG.
It is also possible to obtain an effect that it is not necessary to provide 6 on the ceramic substrate 1.

Here, for example, the package MMIC having the lead terminal according to the embodiment of the present invention shown in FIG.
Characteristics of feedback amount with respect to frequency obtained for chip 3 (hereinafter, referred to as “feedback amount characteristics according to“ the present embodiment ”)”
Is, for example, the characteristic of the feedback amount with respect to the frequency obtained with respect to the conventional packaged MMIC chip having the lead terminals shown in FIG. 6 of the conventional example (hereinafter, referred to as “the feedback amount characteristic according to the“ conventional example ”)”. Compare with Note that the feedback amount referred to here means, for example, as described in the above-mentioned problem, from the output lead terminal (for example, the input / output lead terminal 23 in this example) to the input lead terminal (for example, the input / output lead terminal 2 in this example).
2) This is the amount of signal feedback that occurs when jumping over the ground lead terminal (ground lead terminal 21 in this example).

FIG. 4 shows an example of the feedback amount characteristic according to the above-mentioned "this embodiment" by a solid line as (a), and shows an example of the feedback amount characteristic according to the above-mentioned "conventional example" by (b). ) Is indicated by a dotted line, and the horizontal axis of the graph in the figure indicates the frequency (GHz), and the vertical axis indicates the feedback amount (d).
B) is shown. Here, the feedback amount characteristic according to the "conventional example" shown in FIG. 8 is the same as the characteristic shown in FIG.

As shown in FIG. 4, the input / output lead terminals 22, 2
Since the spatial coupling between the three is smaller than that of the related art (“conventional example”), the feedback amount is reduced over a wide frequency band as compared with the related art (“conventional example”). . As shown in the figure, an unstable state such as oscillation occurs at 33 GHz in the conventional (“conventional example”) lead terminal, but in the present example (“this example”), No steep increase in feedback amount causing abnormal oscillation at a specific frequency occurs, and good high-frequency characteristics are obtained.

In this embodiment, the above-mentioned Kovar plate 2 corresponds to the metal ground plate of the present invention, the above-mentioned ceramic substrate 1 corresponds to the substrate of the present invention, and the above-mentioned package MMIC chip 3 corresponds to the present invention. And the microstrip lines 12 and 13 described above.
Corresponds to the input / output conductor according to the present invention.

Here, the configuration of the lead terminal according to the present invention is not necessarily limited to the configuration described above, and various configurations may be used. For example, in this example, a case where a packaged MMIC chip is used as the high-frequency circuit component has been described. However, various types of high-frequency circuit components according to the present invention may be used.
(MIC bare chip), an HMIC chip, or the like may be used. In addition, various types may be used as the substrate according to the present invention and the metal ground plate according to the present invention, and various methods may be used to connect the conductors.

The ground lead terminal according to the present invention and the through hole according to the present invention may have various shapes. In the present embodiment, as a preferred embodiment, the lower surface of the ground lead terminal (the surface connected to the metal ground plate) is made flat to facilitate the connection between the ground lead terminal and the metal ground plate. In addition, various shapes and arrangements of the input / output lead terminals according to the present invention may be used.

In this embodiment, the case where the ground lead terminal according to the present invention and the input / output lead terminal according to the present invention are provided on the high-frequency circuit component is shown. It can be provided on the board side, and for example, a part or all of the input / output lead terminals can be provided on the board side. As an example, when part or all of the ground lead terminals are provided on the metal ground plate, for example, the metal ground plate can be etched to form a protruding metal portion on the metal ground plate.

Further, in this example, for the sake of simplicity, an example in which one high-frequency circuit component is mounted has been described with reference to FIG. 1 and the like. Also in this case, by using the structure of the lead terminal as shown in this example, the same effect as in this example can be obtained.

[0041]

As described above, according to the lead terminal according to the present invention, the lead terminal of the high-frequency circuit component provided on the substrate provided with the metal ground plate on the back surface is inserted into the through hole provided on the substrate. A ground lead terminal having a shape that fits within the plane of the through hole that connects the high-frequency circuit component and the metal ground plate, and is disposed on both sides of the ground lead terminal and provided on the high-frequency circuit component and the substrate, respectively. Since the input / output conductor and the input / output lead terminal for connecting the input / output conductor are used, for example, even in a super high frequency band such as a microwave band or a millimeter wave band, the high frequency circuit components can be reliably grounded at a high frequency, An unstable state such as oscillation of the high-frequency circuit component can be avoided, and thereby good high-frequency characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a unit mounting a package MMIC chip according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a unit mounted with a package MMIC chip according to one embodiment of the present invention.

FIG. 3 is a bottom view of the package MMIC chip according to one embodiment of the present invention.

FIG. 4 is a diagram comparing the feedback amount with respect to frequency between the embodiment of the present invention and the conventional example.

FIG. 5 is a diagram illustrating an example of a high-frequency integrated circuit unit.

FIG. 6 is a perspective view of a unit on which a packaged MMIC chip according to a conventional example is mounted.

FIG. 7 is a sectional view of a unit on which a packaged MMIC chip according to a conventional example is mounted.

FIG. 8 is a diagram illustrating an example of a feedback amount with respect to a frequency according to a conventional example.

[Explanation of symbols]

1. Ceramic substrate, 2. Kovar plate, 3. Package MMIC chip, 4. Metal housing, 5a ~
5c screw, 11 through hole, 12, 13 microstrip line, 14a to 14d screw through hole, 15a to 15d screw tap, 21 ground lead terminal, 22, 23 input / output Lead terminal,

Claims (1)

[Claims] 1. A lead terminal of a high-frequency circuit component provided on a substrate having a metal ground plate on the back surface, wherein the lead terminal is inserted into a through hole provided in the substrate and connects the high-frequency circuit component and the metal ground plate. A ground lead terminal having a shape that fits in the plane of the hole, and input / output lead terminals arranged on both sides of the ground lead terminal to connect high-frequency circuit components and input / output conductors provided on the substrate, respectively. A lead terminal characterized by being constituted.