JPH0818002A - Inversion mounting type passive element mounting structure - Google Patents

Abstract

PURPOSE:To enable replacing of passive elements on a line farmed on a coplanar line, relating to a compound microwave circuit module and a microwave integrated circuit. CONSTITUTION:An inversion mounting type passive element structure is applied to a compound microwave circuit module and a microwave integrated circuit. In this counting structure, a pattern of an area on a coplanar line 6 on which an inversion mounting type passive element 3 is mounted is removed. Only an overlap width 10, however, far soldering is left. The area an which the inversion mounting type passive element 3 is mounted is where a characteristics of the passive element needs to be changed, and a passive element built in in the process for manufacturing a substrate is replaced with an inversion mounting type passive element. The conductor side of the inversion mounting type passive element 3 is reversed to face the overlap width 10, for soldering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a composite microwave circuit module (hereinafter sometimes abbreviated as MMCM).
The present invention relates to a microwave circuit mounting structure such as the above, and particularly to a mounting structure in which a passive element is reversely mounted on a circuit configured by a coplanar line or the like.

[0002]

2. Description of the Related Art Recently, in order to improve high frequency characteristics, a composite microwave circuit module (for example, Japanese Patent Laid-Open No. 4-2910).
(Publication No. 3), mounting structures such as microwave integrated circuits are touted.

An example of the composite microwave circuit module is shown in FIG. 5 as an overall view and in FIG. 6 as a sectional perspective view. In the composite microwave circuit module, as shown in FIGS. 5 and 6, ground planes are formed in the upper layer (upper layer ground 54) and the lower layer (lower layer ground 53) of the dielectric substrates that are stacked in multiple layers, and the ground plane is formed. A signal circuit (RF signal layer 55) composed of a conductor layer for forming is formed in the middle layer portion. A cavity is formed from the surface layer to the RF signal layer 55, and various elements such as an active element 56 and a passive element are mounted on the cavity. When these elements are mounted, the cavity is covered with a metal seal 52 to protect the elements from dust and moisture.

The RF signal layer 55 is realized by a strip line, a microstrip line, a coplanar line, etc., and a passive element is formed of these lines and is manufactured simultaneously with the RF signal line by large-scale integration at the time of manufacturing a substrate. . The composite microwave circuit module has the above characteristics.

As described above, in the mounting structure of the composite microwave circuit module and the microwave integrated circuit, the passive elements such as the attenuator, the filter, the coupler, etc.
It is built on the same substrate together with the pattern of signal lines.

Also, as a technique for facilitating the component replacement of surface mount components, there is JP-A-4-212440, in which a sub-dielectric substrate which can be easily removed is connected to a main dielectric substrate via a strip line. A part of the circuit having surface-mounted elements of the high-frequency circuit is formed on the sub-dielectric substrate, which is mounted on the main dielectric substrate to be integrated to realize a high-frequency circuit.

[0007]

However, in the mounting structure of the conventional composite microwave circuit module and microwave circuit integrated circuit mentioned above, passive elements such as attenuators, filters, couplers, and the like are used as the RF signal line at the time of manufacturing the substrate. Since they are built together, it is impossible to change the characteristics of these passive elements.

Further, in Japanese Patent Laid-Open No. 4-212440 mentioned above as a technique for facilitating the exchange of surface mount components, since it is a technique for exchanging surface mount components via a strip line, a composite microwave circuit module and It is not suitable as a technique used for a coplanar line which is often used when mounting an active element on a bare chip in a microwave circuit integrated circuit.

The object of the present invention is to solve the above-mentioned problems by mounting the passive element in reverse after the substrate of the composite microwave circuit module or the microwave integrated circuit is manufactured. It is to propose the mounting structure of the element.

[0010]

In order to solve such a problem, according to the first aspect of the invention, a pattern is formed only in a region of the coplanar line in the cavity of the composite microwave circuit module where the reverse mounting passive element is mounted. delete. The region in which the reverse mounting type passive device is mounted is a place where the characteristics of the passive device need to be changed, and thus the passive device built at the time of manufacturing the substrate is replaced with the reverse mounting type passive device. In the part where the pattern is deleted, a soldering margin is left for soldering the reverse mounting type passive element and the composite micro circuit module, and the reverse mounting type passive element is a coplanar line of the composite microwave circuit module. When,
Solder by reversing so that the conductor surfaces face each other. If the reverse mounting type passive element is manufactured with different characteristics according to function, it is possible to select and mount a passive element having appropriate characteristics.

Further, in the invention of claim 4, in the microwave integrated circuit in which the surface layer line is formed of a coplanar line, the pattern is deleted in the portion where the characteristic of the passive element needs to be changed as in the case of claim 1. . In order to solder the reverse mounting type passive element and the microwave integrated circuit, a soldering margin is made, and the reverse mounting type passive element is inverted so that the conductor surfaces of both sides face each other and soldering is performed. Reverse mounting type passive elements are selected and mounted with appropriate characteristics.

[0012]

FIG. 1 is a diagram showing a first embodiment of the present invention.
(A) is a perspective view of a composite microwave circuit module including a reverse mounting type passive element mounting structure, (b) is a partially enlarged view of a cavity including the same mounting structure, (c) is a perspective view of a reverse mounting type passive element, (D) shows a pattern of a region in which the reverse mounting passive element is mounted.

As shown in FIG. 1, the reverse mounting passive element mounting structure of this embodiment comprises a composite microwave circuit module and a reverse mounting passive element 3. A high-frequency signal line is provided in an inner layer of a composite microwave circuit module made of a multilayer ceramic substrate, and a cavity 4 for mounting an active element 2 such as a transistor or a diode is provided in a part of the high-frequency signal line (for example, Japanese Unexamined Patent Publication No. Hei 4- 2910
No. 3 public information). The line in the cavity 4 is the active element 2
In order to mount the above as a bare chip, it must be a coplanar line 6 having a ground on the same surface as the high-frequency signal line. The bare chip active element 2 is soldered to this ground plane. Therefore, the reverse mounting passive element 3 is a coplanar line because it is mounted on the coplanar line.

FIG. 1 (c) is a perspective view showing a reversing / reversing type passive element. The substrate of this reverse mounting passive element is an alumina ceramic substrate of a size that fits inside the cavity of the composite microwave circuit module, and the external dimensions are several [mm].
~ Several + [mm], and the thickness is several hundred [μm]. A high frequency signal line is formed on this ceramic substrate by thin film technology.
When designing the reverse mounting passive device, consider that the reverse mounting passive device (ceramic substrate) with another permittivity is reverse mounted on the composite microwave circuit module substrate with a certain permittivity. , Design the line width of the coplanar line of the reverse mounting passive device. By designing in this way, the impedance discontinuity in the reverse mounting passive element is eliminated, so the return loss is good. The reverse mounting passive element of FIG. 1 showing the present embodiment is a π-type attenuator. In order to improve the high frequency characteristics of the π-type attenuator, the low antibody 9 is made small within the range where accuracy is allowed. Since the reverse mounting passive device is manufactured by the thin film technology as described above, the low antibody can be formed with an accuracy of the order of several [μm]. Since the conductor high-frequency line can be formed with the same accuracy, desired characteristics can be easily obtained. Further, the resistance value of the low antibody can be adjusted by trimming during production.

FIG. 1D is a perspective view showing a reverse mounting type passive element mounting region in the cavity 4. In this region, the conductor of the portion for mounting the reverse mounting type passive device on the coplanar line is deleted. However, in order to invert and solder the reverse mounting passive element on the composite microwave module substrate, the soldering margin 10 has a width of several hundred [μm] as shown by the broken line in FIG. Be provided in.

In the area shown in FIG. 1D, FIG.
The reverse mounting passive element shown in (c) is mounted by soldering. The a ′ surface of the reverse mounting passive element of FIG. 1C is faced to the area of FIG. 1D. That is, the a'plane of FIG. 1C faces the a plane of FIG. 1D, and the ground planes and coplanar lines on both sides are aligned and soldered so that they are connected to each other. . As a result, a reverse mounting type passive element structure as shown in FIG. 1B is realized. As shown in FIG. 1B, by mounting the passive elements in reverse on the coplanar line, a wide band and low loss connection is possible. As shown in this figure, active elements such as transistors and diodes are soldered to the ground surface in the cavity by bare chips and electrically connected by wire bonds 8. When the mounting of these elements is completed, the cavity 4 is covered with a metal seal 5 to protect the active elements from dust and moisture.

A mounting procedure of the reverse mounting passive element when a part of the frequency negative feedback circuit (hereinafter referred to as a PLL circuit) is specifically mounted on the composite microwave circuit module will be described. FIG. 2 is a block diagram of the PLL circuit. PLL
The circuit basically has a voltage controlled oscillator 11 (hereinafter referred to as VCO) buffer amplifier 12, a prescaler 14, a program counter 15, a phase comparator 16, and a low-pass filter 17 (hereinafter referred to as LPF). Load 18
Is connected. Among these, the VCO 11, the buffer amplifier 12, the prescaler 14, and the element shown by the broken line 19 in the figure of the load 18 are mounted in the MMCM.

The PLL circuit will be briefly described below.
The PLL circuit is a circuit configured to always keep the output signal frequency constant with respect to the load. VCO11 is f
_Suppose that it oscillates at a frequency called _VCO . Buffer amplifier 1
2 amplifies the amplitude without changing the oscillation frequency f _VCO . This signal is led to the load 18, but part of it is the prescaler 1
4 is input. The prescaler 14 has a function of dividing a high frequency (for example, ten and several [GHz]) into 1 / M (the frequency of the input signal becomes 1 / M). Then, the program counter 15 similarly divides the frequency of the input signal into 1 / N. However, the frequency division ratio N of the program counter 15 is variable. The phase comparator 16 has a reference frequency f _r
And a pulse signal corresponding to the phase difference between the comparison frequency f _P and.
The output of the program counter 15 is this comparison frequency f _P. This pulse signal is converted into L. P. It is converted to a DC voltage by F17 and fed back to the VCO 11. At this time VCO1
1 of the output frequency f _VCO becomes _{f VCO = N × M × f} r. In this way, the output frequency of the PLL circuit is always kept constant. In this PLL circuit, the input signal level of the prescaler 14 must be a constant value. However, in reality, it is difficult to keep the input level of the prescaler 14 constant due to characteristic variations and temperature characteristics of the active elements used in the VCO 11 and the buffer amplifier 12. Therefore, the output level of the buffer amplifier 12 is measured, the attenuation amount of the attenuator 13 is determined so as to match the input of the prescaler 14, and the attenuator 13 is mounted before the prescaler input to keep the prescaler input level constant. Is possible. This attenuator 13 is realized by a reverse mounting passive element structure.

FIG. 3 is a diagram showing a modified example of the mounting example of FIG.

The embodiment of FIG. 3 (a) is an application of the first embodiment of the composite circuit module of FIG. 1, and the dimension between the walls of the cavity 21 (inner dimension) is the same as the outer dimension of the reverse mounting passive element 20. And the structure facilitates alignment during soldering.

The high frequency signal line of the composite microwave circuit module is provided in the inner layer, and the high frequency signal line in the cavity 22 for mounting the bare chip of the active element is formed by a coplanar line, which mounts the reverse mounting type passive element. It is connected to the cavity 21. When the reverse mounting passive element 20 is mounted in this cavity 21,
The high-frequency signal line in the cavity 21 becomes a coplanar line. However, until the reverse mounting passive element 20 is mounted, the cavity 21 has only the soldering margin 28 for mounting the reverse mounting passive element (FIG. 3B).

By constructing the structure in which the relationship between the internal dimensions in the cavity and the external dimensions of the reverse mounting passive element is matched as described above, it is only necessary to reverse and drop the reverse mounting passive element in the cavity. Positioning is possible,
Manufacturability is improved. This cavity does not necessarily need to be covered with a metal seal because it is a passive element only.

FIG. 4 is a perspective view of the second embodiment of the present invention. This embodiment is different from the first embodiment and is applied to a microwave integrated circuit. The microwave integrated circuit board 32 mounted on the metallic pedestal 31 is a coplanar line 34.
The bare chip of the active element 36 is mounted on the surface of the ground 38 and is electrically connected to the coplanar line 34 by the bonding wire 35. The coplanar line in the portion where the reverse mounting passive element 33 is mounted is deleted, and the portion surrounded by the broken line serves as a soldering margin 39 when the reverse mounting passive element is inverted and soldered. In the structure of FIG. 4, the reverse mounting passive element 33 is the substrate 3
Since it is directly soldered to 2, the wide band and low loss connection is possible, and since the reverse mounting type passive element 33 can be connected to the coplanar line, it can be mounted on the same surface as the bare chip active element, It is further improved in the direction of loss and wide band. After these elements are mounted, the metal cap 37 covers the elements to protect the active elements from dust and moisture.

[0024]

As described above, according to the inventions of claims 1 and 4, the composite microwave circuit module,
Alternatively, in the microwave integrated circuit, the passive element can be replaced with one having a desired characteristic, so that the passive element can be mounted corresponding to the characteristic variation of the active element. In particular, in the present invention, since the reverse mounting type passive element is mounted by the coplanar line, it is possible to perform the mounting by utilizing the feature that the ground surface and the high frequency signal line are on the same surface. The feature is that the ground plane is near the high-frequency signal line when the active element is mounted on the bare chip, so it is stable at high frequencies,
The reverse mounting passive element can be mounted near the same surface as the active element.

Further, in the present invention, as the reverse mounting type passive element, it is possible to replace the passive element with one having different characteristics, so that the flexibility of the composite microwave circuit module and the microwave integrated circuit is improved. Since the connection structure is simple, broadband and low-loss connection can be made, and the assembling property can be improved.

According to the third aspect of the present invention, the positioning when mounting the reverse mounting element is facilitated, and the assemblability is further improved.

Cost reduction can be achieved by using the reverse mounting type passive element commonly for various composite microwave circuit modules and microwave integrated circuits.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention, in which (a) is a perspective view of an MMCM including a reverse mounting passive element mounting structure;
(B) is a partially enlarged view of a cavity including a reverse mounting type passive element mounting structure, (c) is a perspective view of the reverse mounting type passive element,
(D) is a pattern diagram of a region in which the reverse mounting passive element is mounted.

FIG. 2 is a basic configuration diagram of a PLL circuit.

FIG. 3 is a perspective view (a) of a modification of the first embodiment shown in FIG. 1 and a top view (b) of a reverse mounting type passive element mounting cavity in this modification.

FIG. 4 is a perspective view showing a second embodiment of the present invention.

FIG. 5 is an overall view of a conventional composite microwave circuit module.

6 is a detailed cross-sectional view of the composite microwave circuit module shown in FIG.

[Explanation of symbols]

 1 Composite Micro Module 2 Active Element (Bare Chip) 3 Reverse Mounting Type Passive Element 4 Cavity 5 Metal Seal 6 Coplanar Line 7 GND 8 Wire Bonding 9 Resistor 10 Solder Allowance 11 Voltage Controlled Oscillator 12 Buffer Amplifier 13 Attenuator by Reverse Mounting Type Passive Element 14 Prescaler 15 Program Counter 16 Phase Comparator 17 Low Pass Filter (LPF) 19 Part of PLL Circuit Mounted on MMCM 20 Reverse-Mounting Passive Element 21 Reverse-Mounting Passive Practical Cavity 22 Active Device Mounting Kyobi 23 wire bonding 24 composite microwave circuit module 25 active element 26 bonding wire 27 coplanar line 28 soldering margin 29 input / output terminal 30 power supply terminal 31 pedestal 32 wiring board 33 reverse Mounted passive element 34 Coplanar line 35 Bonding wire 36 Active element 37 Metal cap 38 GND 39 Solder allowance 40 Multilayer dielectric substrate (SVB) 41 Base plate 42 Voltage controlled oscillator (VCO) 43 Amplifier (AMP) 44 Prescaler (PSC) 45 Mixer (MIX) 46 Variable attenuator (ATT) 47 Power amplifier (AMP) 48 Detector (DET) 49 Directional coupler (DC) 50 Band pass filter (BPF) 51 Low pass filter 52 Metal seal (CAP) 53 Lower Ground Layer 54 Upper Ground Layer 55 RF Signal Layer 56 Active Element 57 Via 58 Bonding Wire 59 Signal Pattern 60 Power Supply Pattern

Claims (4)

[Claims] 1. A composite microwave circuit module in which a cavity is formed by scribing from a high-frequency signal line in the inner layer of a multilayer structure to a surface layer, and the high-frequency signal line exposed at the bottom of this cavity is a coplanar line in a reverse mounting passive type. In a structure for mounting an element, at least a part of a conductor in an area for mounting the reverse mounting passive element in the cavity is removed to block a part of the coplanar line, and the reverse mounting passive The coplanar line and the ground surface necessary for making an electrical connection between the element and the composite microwave circuit module are left in the cavity as a soldering margin so that the conductor surface of the reverse mounting passive element rides on the soldering margin. The reverse mounting type passive element and the composite microwave circuit module. Reverse-mounted passive element mounting structure, wherein the lines and the ground are soldered to one another. 2. The reverse mounting type passive element is an attenuator,
It has a function of a filter, a coupler, etc., and is manufactured by using thin film technology using ceramics as a substrate material, and when it is reversely mounted on the substrate of the composite microwave circuit module, The reverse mounting passive element mounting structure according to claim 1, wherein the impedance of the coplanar line is substantially equal to the impedance of the coplanar line in the composite microwave circuit module. 3. The planar shape of the substrate of the reverse mounting passive element and the planar shape of a cavity in which the reverse mounting passive element is mounted are matched with each other. Reverse mounting type passive device mounting structure. 4. In a structure in which a reverse mounting type passive element is mounted on a microwave integrated circuit in which a high-frequency signal line of a surface layer is formed by a coplanar line, in a region of the coplanar line where the reverse mounting type passive element is mounted. At least a part of the conductor is deleted, and a conductor as a soldering margin is left for making electrical connection between the reverse mounting passive element and the microwave integrated circuit, and the reverse mounting passive element is A reverse mounting type passive element mounting structure, wherein the conductor surface is reversed so as to ride on the soldering margin and is soldered to the soldering margin.