JP2003068907A - High-frequency function module and its multi-layered mount structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize the mount size reduction, standardization, automatic mounting, yield improvement, and cost reduction of a high-frequency function module by mounting single-function modules in three dimensions instead of mounting components on the same surface. SOLUTION: A single function module is constituted by mounting function element components such as MMIC (monolithic microwave integrated circuit) 3 or the like in a bottomed cavity 2 formed in a package 1 and electrically connects the components to the package 1 by bonding wires 4. Through FR interfaces 5 and 6 in coaxial structure provided on the top and reverse surfaces of the package 1 and a DC interface 7 penetrating the package vertically, the signals of the MMIC 3 are outputted to the outside through a connecting circuit 8 in the package 1. A cap 9 forms an airtight sealing structure. Such single- function modules are longitudinally stacked and their interfaces are connected to one another by solder fusion by reflow to obtain a multi-layered high-frequency function module structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency circuit module used in a communication device in a microwave band or a millimeter wave band, and more particularly to a single-function module containing a high-frequency function element in a functional block unit and a third-function module of these single-function modules. The present invention relates to a multilayer mounting structure of originally laminated high frequency functional modules.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view showing an example of a typical mounting form of a conventional high frequency functional module MIC (microwave integrated circuit).

In a conventional high frequency circuit module, a plurality of MMIC (monolithic microwave integrated circuit) bare chips 63, which are functional elements, are arranged in a header 62 on a metal package 61, as shown in FIG. A plurality of alumina ceramic substrates 64 on which are formed are arranged, the bonding wires are connected between them, and they are mounted side by side on the same surface of the metal package 61.
The high frequency functional module is configured by covering with a cap 65 as a hermetic seal that prevents external leakage of F signals. The interface with the outside is performed by the glass sealed terminal 66.

In the conventional high-frequency functional module having such a structure, the degree of integration thereof is increasing year by year due to the progress of the MMIC manufacturing technology, and the transmission / reception converter circuit which has conventionally been composed of 2 packages to 4 packages is reduced to one package. It can be aggregated.

[0005]

As described above, the conventional high-frequency functional module has a structure in which a plurality of MMIC bare chips and a plurality of alumina ceramic substrates are mounted side by side on the same surface of the metal package. There is a problem that there is a limit to miniaturization.

Further, since the MMIC is supplied in the form of a bare chip, screening such as burn-in is performed after it is mounted on the package. Therefore, even if only one MMIC has a defect, the entire package becomes a defective product. This is one of the causes of the decrease in yield.

Further, since many parts are to be mounted in the package, it takes a long time to assemble the device, and the device is exposed to a high temperature which causes a decrease in reliability, which results in a decrease in reliability as a whole. There's a problem.

An object of the present invention is to revise the conventional idea of mounting a plurality of components on the same surface of a package, configure a single-function module for each functional block, and mount a plurality of these single-function modules three-dimensionally. SUMMARY OF THE INVENTION It is an object of the present invention to provide a high-frequency functional module and a multi-layer structure thereof that solve the above conventional problems.

[0009]

A high frequency functional module of the present invention is a package having a bottomed cavity hole, a high frequency functional element mounted in the cavity hole, the cavity hole and the high frequency functional element. A metal plate attached to the package so as to seal and seal the above, an RF interface portion provided at at least one each on the upper surface and the lower surface of the package, and a plurality of DCs provided so as to pass through the package from above and below.
Interface section, high-frequency functional element, and RF
An interface section and a connection section for electrically connecting the DC interface section are provided.

In this high frequency functional module, the package is a dielectric substrate, and the high frequency functional element is a monolithic microwave integrated circuit (MM).
IC) is preferred.

In this high frequency functional module,
The dielectric substrate is made of low temperature fired ceramics (LTCC) stacked in multiple layers, or the high temperature fired ceramics (H) in which the dielectric substrates are stacked in multiple layers.
TCC).

Further, in this high frequency functional module, it is preferable that the RF interface section has a coaxial structure and that at least two high frequency functional elements are mounted in the cavity hole.

Another high-frequency functional module of the present invention is a printed wiring board having a cavity hole formed therethrough, and is mounted on the printed wiring board so as to cover the cavity hole made of a material having a high thermal conductivity. A metal plate; a high-frequency functional element mounted on the metal plate in the cavity hole; a metal cap attached to the printed wiring board so as to seal and seal the cavity hole and the high-frequency functional element; and the printed wiring. At least one RF interface section is provided on each of the upper surface and the lower surface of the board, a plurality of DC interface sections are provided so as to penetrate the printed wiring board up and down, the high-frequency functional element, the RF interface section, and the DC interface section. And a connection part that electrically connects between It becomes Te.

Further, the multilayer mounting structure of the high-frequency functional module of the present invention is formed by stacking a plurality of the high-frequency functional modules as described above in the vertical direction and connecting the RF interface parts to each other and the DC interface parts to each other. .

According to the high-frequency functional module and the multilayer mounting structure thereof of the present invention as described above, the following features can be obtained.

(1) Each of the functional blocks constituting the characteristic module of the mounting structure is put in one package to prepare a single-function module, and these single-function modules are vertically stacked to have a predetermined function. A high frequency module (three-dimensional mounting) can be realized.

(1a) Structure of a single-function module A cavity in which functional element parts such as MMIC are mounted is formed in the package, and the functional element parts are mounted in the cavity, and the upper part of the cavity can be sealed with a thin metal. To do.

At least one RF interface section is owned in the upper part of the package, and at least one RF interface section is also owned in the lower part of the package.
Further, a plurality of DC interfaces are mounted so as to penetrate between the top and bottom of the package. By supplying solder to each of these interfaces and melting them at the time of stacking, it is possible to electrically connect the single-function modules.

(1b) Structure of high-frequency functional module A plurality of single-functional modules may be vertically stacked and the solder supplied to the terminals may be melted in advance to connect the modules to each other.

(1) Characteristics of mounting material As the mounting material constituting the single-function module, not only inorganic materials such as HTCC (high temperature firing ceramics) and LTCC (low temperature firing ceramics) but also packages of organic materials can be selected. . In addition, along with this, there is a possibility that optimum material selection can be performed according to the characteristics of each functional module.

(1) Other Features The RF interface can have a waveguide type interface structure as well as a coaxial structure.

As means for laminating a plurality of functional modules, it is possible to use soldering as well as bonding with a conductive adhesive.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

1 (a) and 1 (b) are a longitudinal sectional view and a plan view of a single function module constituting the high frequency function module according to the first embodiment of the present invention.
1B shows a state in which a plurality of single-function modules according to the first embodiment are vertically stacked, each of which is taken along the line AA in FIG.
FIG. 3 is a vertical cross-sectional view taken along line B-B and line B-B, and FIGS. 3A and 3B are a circuit block diagram and a configuration diagram showing an example of such a multilayer mounting structure.

In the high frequency single-function module of the first embodiment, as shown in FIGS. 1A and 1B, a cavity 2 having a bottom is formed and punched inside the package 1, and the cavity 2 is formed in the cavity 2. Is mounted with functional element parts such as MMIC (monolithic microwave integrated circuit) 3.

The package 1 is a dielectric substrate laminated in multiple layers, and its material is a multilayer LTCC having a low coefficient of thermal expansion.
(Low temperature firing ceramics) is used.

As for the method of mounting the functional element component, that is, the MMIC 3 inside the cavity 2, the normal soldering using a high temperature brazing material is used. In addition to this soldering mounting, it is also possible to use means such as component mounting using a conductive adhesive or face-down mounting using bumps.
The MMIC 3 mounted inside the cavity 2 in this way
For example, the component and the package 1 are electrically connected by the bonding wire 4 or the like.

At least one RF interface 5 is provided on the upper surface of the package 1, and at least one RF interface 6 is provided on the lower surface of the package 1. In addition, this RF interface 5
The RF interface 6 and the RF interface 6 are preferably formed in a coaxial structure.

A plurality of DC interfaces 7 are provided on the surface of the package 1 in the longitudinal direction. D
The C interface 7 is mounted so as to penetrate between the upper and lower sides of the package 1, and has a role of taking out the wiring inside the package 1 to the outside.

Solder is supplied to each of these interfaces (RF interfaces 5 and 6 and DC interface 7) and melts when a plurality of single-function modules to be described later are laminated to electrically connect the single-function modules. You can

Inside the package 1, the mounted MM
A connection circuit 8 for electrically connecting the IC 3 to the RF interfaces 5 and 6 and the DC interface 7 is provided.

A cap 9 made of a thin metal plate is attached to the upper surface of the package 1 by brazing. The cap 9 includes the cavity 2 in the package 1 and the mounted M
The MIC 3 is hermetically sealed to form a metal closed space in the package 1. The cap 9 is
The thickness of the package 1 is determined so that it does not protrude from the upper surface of the package 1 when attached (usually about 0.1 mm). The cap 9 may be attached not only by brazing but also by using a conductive adhesive for hermetic sealing.

In the above-mentioned state, solder is supplied to the RF interfaces 5 and 6 and the DC interface 7 by means such as solder printing or ball supply.

A plurality of the single-function modules of the first embodiment thus configured are vertically stacked. This state is shown in FIG.

In FIG. 2, four single-function modules formed in the package 1 as described with reference to FIG. 1, that is, high-frequency single-function modules 11, 12, 13, and 14 are vertically stacked.

FIG. 2A shows a laminated state in the same sectional state as FIG. 1A, and the high frequency single-function modules 11, 12, 13, 14 provided in the longitudinal direction are provided respectively. The RF interface 5 and the RF interface 6 are connected to each other.

In FIG. 2B, BB in FIG.
The laminated state in the cross section taken along the line is shown, and each high frequency single-function module 11, 12, 1 is laminated in the longitudinal direction.
The parts 3 and 14 are connected by the DC interface 7 provided in each part.

The stacking work of a plurality of single-function modules can be carried out manually, or can be carried out by using a surface mount component mounter whose height can be controlled.

The plurality of single-function modules stacked in the state shown in FIG. 2 are then passed through a reflow furnace to melt the solder that has been supplied to the terminals of each interface portion in advance, and the single-function modules are loaded by the weight of the package itself. The upper and lower sides of the are connected to form a multilayer high frequency module structure having a predetermined function.

FIG. 3 shows an example of such a multi-layered high frequency module. FIG. 3A is a circuit block diagram of the frequency conversion / amplification circuit, and FIG. 3B is a configuration diagram of the multilayer stack mounting.

As shown in FIG. 3 (a), this circuit changes from the modulated intermediate frequency (IF) to the transmission frequency (R).
It is a circuit whose purpose is to perform frequency conversion into F) and to perform power amplification necessary for transmission.

A frequency signal necessary for conversion is generated by an oscillator (LO-
Oscillator 21 oscillates, amplifier (AMP) 22 amplifies, mixer (MIX) 24 mixes with the intermediate frequency, only RF is taken out, and the signal is output to driver amplifier (Drive) 25 and power amplifier ( PA) 27
The power is amplified to the power required for transmission and supplied to the antenna. The LO-OSC 21 is connected to a prescaler (PSC) 23 that divides the oscillation frequency necessary for controlling the oscillation frequency and supplies the divided frequency to the PLL circuit. Further, transmission power is provided between the driver stage and the PA stage. A variable power attenuator (Atten) 26 necessary to keep constant is inserted. DET 28 is a detector.

Each of these functional blocks is assembled and adjusted as a single functional module, and as shown in FIG. 3B, the (OSC + PSC) functional module 31, the AMP functional module 32, the MIX functional module 33, and the Dri.
ve function module 34, Atten function module 3
5 and the (PA + DET) function module 36, all of them are vertically stacked and the interface portions of the respective modules are interconnected to realize the multi-layer high-frequency function module 30 having the above-described purposes and functions.

FIG. 4 is a plan view showing a high frequency single function module using a plurality of chips according to the second embodiment of the present invention.

The single-function module of the second embodiment shows that the high-frequency functional element to be used is not limited to a single chip, but can be composed of a plurality of chips (high-frequency functional element). Driver as an example
FIG. 4 shows a configuration example of the unit.

As shown in FIG. 4, the multi-chip single-function module 40 includes a plurality of MMICs (Amp), that is, MMIC 43 and MMIC 44, in one package 41.
A single-function module is constructed by incorporating and mounting in a cavity 42 inside, and connecting between them by a chip connection substrate 45. Since the other components such as the RF interface, DC interface, bonding wire, and hermetically sealing cap are the same as those shown in FIGS. 1A and 1B of the above-described first embodiment,
The description is omitted.

Needless to say, the multi-chip single-function module 40 of the second embodiment can be vertically stacked in the same manner as that shown in FIG. 2 of the first embodiment.

By forming a multi-chip single-function module as described above, the number of laminated modules can be reduced, leading to cost reduction. Further, even if the performance (gain, distortion, etc.) required of the single-function module is changed due to the specification change, the element configuration can be changed without making a large change in the design.

In the above-described first and second embodiments, the packages 1 and 41 are dielectric substrates laminated in multiple layers, and the material thereof is a multilayer LTCC (low temperature firing ceramics) having a low coefficient of thermal expansion. However, the present invention is not limited to this, and multilayer HT such as alumina ceramics or aluminum nitride is used as a package material.
It is also possible to use it by changing it to a CC (high temperature fired ceramic) material. In this case, the thermal resistance of the package can be reduced, and improvement of heat dissipation characteristics can be expected.

Next, a third embodiment of the present invention will be described.

FIG. 5 is a vertical sectional view of a single function module which constitutes the high frequency function module of the third embodiment.

In the third embodiment, a printed wiring board 51 is used instead of the packages 1 and 41 described above. A cavity 52 is formed penetrating the printed wiring board 51, and a heat dissipation plate 54 is attached to the printed wiring board 51 so as to close the cavity 52. The heat dissipation plate 54 is formed of a thin metal plate made of a material such as copper having high thermal conductivity.

Functional element parts such as an MMIC (monolithic microwave integrated circuit) 53 are mounted on the heat sink 54 in the cavity 52. As the mounting and mounting method of the MMIC 53, a method such as brazing with a normal high-temperature brazing material, mounting of a component with a conductive adhesive, or face-down mounting with bumps is used. Thus, the M mounted on the heat sink 54 inside the cavity 52
With respect to the MIC 53, the component and the printed wiring board 51 are electrically connected by a bonding wire 60 or the like.

On the upper surface and the lower surface of the printed wiring board 51, one or more RF interfaces 55 and 56 are provided as in the above-described embodiment. It is preferable that the RF interface 55 and the RF interface 56 have a coaxial structure.

On the surface of the printed wiring board 51, a plurality of DC interfaces 57 are mounted in the longitudinal direction of the printed wiring board 51 so as to penetrate between the upper and lower sides of the printed wiring board 51, as in the above-described embodiment. It has a role to take out the internal wiring to the outside.

Solder is supplied to each of these interfaces (RF interfaces 55 and 56 and DC interface 57) and melts when a plurality of single-function modules are laminated, whereby the single-function modules can be electrically connected. .

Inside the printed wiring board 51, a connection circuit 58 for electrically connecting the mounted MMIC 53 to the RF interfaces 55 and 56 and the DC interface 57 is provided.

A cap 59 made of a thin metal plate is attached to the upper surface of the printed wiring board 51 by brazing, and the cavity 52 and the mounted MMIC 53 are hermetically sealed so that the printed wiring board 51 has a metal closed space. To form a structure.

In the above-mentioned state, the solder is supplied to the RF interfaces 55 and 56 and the DC interface 57 by means of solder printing or ball supply. It is possible to stack a plurality of single-function modules of the third embodiment having such a configuration in the vertical direction,
This is similar to the case shown in FIG. 2 in the first embodiment.

According to the single function module of the third embodiment, the MMIC 5 which is a high frequency functional element component.
Since the heat generation amount of 3 is large in many cases, the MM is directly attached to the heat dissipation plate 54 made of a thin metal plate having a high thermal conductivity.
By adopting the configuration in which the IC 53 is mounted, the thermal resistance of the printed wiring board 51 can be reduced to enhance the heat dissipation effect, and the package can be provided at a lower cost than the ceramic material as described above.

In each of the above-mentioned embodiments, R
Although the F interface is illustrated as being formed in a coaxial structure, the present invention is not limited to this, and a waveguide type interface structure may be used.

As for the package material forming the single-function module, not only inorganic materials such as HTCC and LTCC but also organic material packages can be selected. As a result, it is possible to select the optimum material according to the characteristics of each functional module.

[0063]

According to the high-frequency functional module and the multilayer mounting structure thereof of the present invention described above, the functional blocks constituting the module are housed in one package to form a single-functional module, and the single-functional modules are vertically arranged. By stacking a plurality of layers in the direction, a high-frequency module (three-dimensional mounting) having a predetermined function can be realized.

Further, according to such a configuration of the present invention,
The following various effects that solve the conventional problems can be obtained. (A) The projected area of the package is reduced, and the device in which this module is mounted can be downsized. (B) Since the single-function modules can be combined after being inspected and screened, the overall yield is improved. (C) Since the number of parts to be incorporated into the single-function module is small and the time required for assembly is short, the heat load at the time of assembly that reduces the reliability of the MMIC is small, and the reliability of the module can be improved. (D) It is possible to standardize the package, reduce the types of inspection jigs required for processes such as inspection and burn-in, and reduce the amount of capital investment. (E) Optimum material selection is possible by using a single-function module, and cost reduction is easy. (F) Since each functional block is packaged, interference between circuits is less likely to occur due to electromagnetic wave wraparound. (G) Only the failed single-function module can be replaced for repair.

[Brief description of drawings]

FIG. 1A is a vertical sectional view and FIG. 1B is a plan view showing a single-function module that constitutes a high-frequency function module according to a first embodiment of the present invention.

FIG. 2 shows a state in which a plurality of single-function modules according to the first embodiment are vertically stacked, and (a) shows A- of FIG. 1 (b).
1B is a vertical cross-sectional view taken along the line A-B in FIG. 1B.

FIG. 3 shows an example of a high-frequency module in which the single-function module according to the first embodiment is vertically multi-layered, (a)
Is a circuit block diagram, and (b) is a configuration diagram of the multi-layer stack mounting.

FIG. 4 is a plan view showing a high frequency single function module using a plurality of chips according to a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view showing a single function module that constitutes a high frequency function module according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing an example of a typical mounting form of a conventional high-frequency functional module.

[Explanation of symbols]

1,41 package 2,42,52 cavity 3,43,44,53 MMIC 4,60 Bonding wire 5, 6, 55, 56 RF interface 7,57 DC interface 8,58 connection circuit 9,59,65 cap 11, 12, 13, 14 High frequency single function module 21 Oscillator (LO-OSC) 22 Amplifier (AMP) 23 Prescaler (PSC) 24 Mixer (MIX) 25 Driver Amplifier (Drive) 26 Variable Power Attenuator (Atten) 27 Power Amplifier (PA) 28 Detector (DET) 30 Multi-layer high frequency function module 31 (OSC + PSC) function module 32 AMP function module 33 MIX function module 34 Drive Function Module 35 Atten function module 36 (PA + DET) function module 40 multi-chip single function module 45 Chip connection substrate 51 printed wiring board 54 Heat sink 61 metal package 62 header 63 MMIC bare chip 64 Alumina ceramic substrate 66 Glass sealed terminal

Claims (9)

[Claims] 1. A package having a bottomed cavity hole, a high-frequency functional element mounted in the cavity hole, and attached to the package so as to seal and seal the cavity hole and the high-frequency functional element. A metal plate, at least one RF interface portion on each of the upper surface and the lower surface of the package, and a plurality of D interface portions that penetrate the package from above and below.
C interface section, the high-frequency functional element, and the R
A high-frequency functional module comprising: an F interface unit and a connection unit electrically connecting the DC interface unit. 2. The high frequency functional module according to claim 1, wherein the package is a dielectric substrate. 3. The high frequency functional module according to claim 1, wherein the high frequency functional element is a monolithic microwave integrated circuit (MMIC). 4. The high frequency functional module according to claim 1, wherein the dielectric substrate is made of low temperature co-fired ceramics (LTCC) laminated in multiple layers. 5. The high frequency functional module according to claim 1, wherein the dielectric substrate is made of high temperature fired ceramics (HTCC) laminated in multiple layers. 6. The high frequency functional module according to claim 1, wherein the RF interface unit has a coaxial structure. 7. The at least two high-frequency functional elements are mounted in the cavity hole.
7. The high-frequency functional module according to any one of 1 to 6. 8. A printed wiring board having a cavity hole formed therethrough, a metal plate made of a material having a high thermal conductivity and attached to the printed wiring board so as to close the cavity hole, and inside the cavity hole. A high-frequency functional element mounted on the metal plate, a metal cap attached to the printed wiring board so as to seal and seal the cavity hole and the high-frequency functional element, and at least an upper surface and a lower surface of the printed wiring board, respectively. 1
An RF interface part provided at each location, a plurality of DC interface parts provided so as to pass through the printed wiring board from above and below, and the high-frequency functional element, the RF interface part, and the DC interface part are electrically connected. A high-frequency functional module comprising: a connection part. 9. A plurality of the high-frequency functional modules according to claim 1 are vertically stacked to form the R
A multilayer mounting structure of a high-frequency functional module, characterized in that F interface parts are connected to each other and the DC interface parts are connected to each other.