JP2002158509A - High-frequency circuit module and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-frequency circuit module, with which repair work is enabled by simple operations, and the deterioration of electric characteristics is prevented. SOLUTION: A semiconductor device 1 is flip-chip bonded to a first signal line 22 on a carrier board 20. On a main substrate 50, a second signal line 52 is formed, the first signal line 22 and the second signal line 52 are connected by a connecting part composed of a connecting electrode 251 and a solder 35, provided on the sidewall of the carrier board, and the carrier substrate 20 is mounted secondarily on the main substrate 50.

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 and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, IT represented by the Internet
As high-speed and large-capacity communication means in the field of (Information Technology), in particular, wired communication devices using optical fibers and the like and wireless communication devices using microwaves and millimeter waves have been remarkably popularized. High-frequency transistors and MMICs (Mono
lithic Microwave Integrat
ed Circuit) or the like. Since this type of device operates in a high-frequency region exceeding GHz, a semiconductor device having excellent high-frequency characteristics, especially gallium arsenide (G
aAs) Semiconductors are often selected.

In order to complete the electronic circuit by combining the above semiconductor elements, a plurality of electrodes formed on the surface of a bare semiconductor element called a bare chip are electrically connected to an external circuit. Wiring must be provided. Generally, in a semiconductor element, such a portion is connected by ultrasonic bonding of a metal wire such as a gold wire or an aluminum wire between an electrode pad of the semiconductor element and a corresponding external electrode. . However, especially in the case of an electronic circuit operating in a high-frequency region, mechanically connecting a pad electrode of a semiconductor element and an external electrode with a metal wire increases the parasitic inductance and the parasitic capacitance caused by the wire connection, and the connection portion In this case, impedance mismatching is caused, so that the original performance of the semiconductor element cannot be exhibited. As a result, loss occurs in transmission of a high-frequency signal, resulting in an inefficient electron. It becomes a circuit. As one means for solving the above problem, a flip-chip mounting method, which is a method for connecting semiconductor elements without using metal wires, has been developed.

FIGS. 7 (a) and 7 (b) show Japanese Patent Application Laid-Open No. 3-120.
736 is an explanatory view showing a state in which a semiconductor chip is flip-chip mounted on a substrate, (a) is a cross-sectional view thereof, and (b) is a plan view seen from the semiconductor chip side. 41 is a semiconductor chip, 42 is a ceramic substrate,
43 is a module frame, 44 is a chip wiring, 45 is a bump, and 46 and 47 are substrate wirings. That is, a ceramic substrate 42 on which substrate wirings 46 and 47 are formed is mounted on a metal module frame (semiconductor package) 43. At this time, the substrate wirings 46 and 47 form a coplanar transmission line, the substrate wiring 46 becomes a signal line, and the substrate wiring 47 becomes a ground line. The bumps 45 are formed on the substrate wirings 46 and 47, and the semiconductor chip 41 is mounted with the circuit surface facing the ceramic substrate 42 side. The physical connection between the insulating substrate and the semiconductor chip is made by alloying the bump itself or using a hardening type resin. By mounting as described above, the connection of the semiconductor element without using the metal wire described above is realized, and it is possible to minimize the electric loss of the connection portion between the semiconductor chip and the ceramic substrate. .

[0005] By the way, the amount of information to be transmitted per unit time is dramatically increased with the increase in the speed and capacity of information communication, and in order to cope with this, the installation space is limited as communication equipment. It is necessary to efficiently store a large-scale circuit system inside the system, and further downsizing of system components and the like is required. On the other hand, in a case for housing a high-frequency circuit, a circuit board, a semiconductor package, and the like, a ceramic or metal package having a hermetically sealed structure is employed from the viewpoint of high performance and high reliability. Such packages have the disadvantages of being very large and expensive, because performance and reliability are paramount.
In the era when reliability was the highest priority, there was not much problem even if the size of the equipment and auxiliary equipment was large. However, recently, miniaturization is a very important factor for the reasons described above. Further, in the past, in the era when the system price was expensive, the cost of such a package occupied a small percentage of the cost of the entire system, and cost reduction was not so important. However, recently, in a social environment where it is necessary to provide high-quality and high-performance systems at low prices, cost is an important factor that cannot be ignored and cost must be reduced as much as possible.

The above-mentioned problem of wire connection is not limited to the problem between a semiconductor element and a semiconductor package containing the element, but also applies to the connection between a semiconductor package and an external circuit such as a wiring board on which the package is mounted. It is. Conventionally, high-frequency compatible semiconductor packages and external circuits have been connected by wire bonding or ribbon bonding using a ball bonder or wedge bonder, and almost no gold wire or gold ribbon is used as the material metal except for special cases. Used. These connection operations are performed manually or by automated devices.In the case of manual operations, there is a need to provide a certain margin for smooth operation of the machine due to variations in the proficiency of the work and individual differences. In addition, since it is necessary to reduce the working time, it is generally difficult to realize the mounting in which the wire bonding is performed without variation in the shortest distance where the inductance can be suppressed to the minimum value.

In order to solve this problem, a connection method without using a bonding wire has been developed for connection between a semiconductor package and an external circuit.
No. 39 discloses an example of a mounting method using no metal wire. This publication describes a method of connecting a module including a semiconductor element flip-chip mounted on a flexible substrate to an external circuit via a metal bump. FIG. 8 is a cross-sectional view illustrating a state in which a semiconductor element is mounted on a package and is mounted by pressing according to the method described in the above publication. In FIG. Is a high-frequency signal wiring, 64 is a first metal bump, 65 is a second metal bump, 66 is a package, 67 is a high-frequency signal wiring of a package, 68 is a semiconductor element receiving cavity, 69 is a bonding tool, 70 is a bonding tool. It is a semiconductor element.

That is, the first metal bump 64 on the flexible substrate 61 is pressed and heated by using a bonding tool 69 to apply pressure and heat to the metal bump 64 so that the metal bump 64 and the package wiring are connected. It describes a method of bonding with an electrode terminal or wiring of another wiring board 67 or another wiring board. According to the above publication, connection of a flexible wiring board to a package is performed by first attaching a flexible substrate 61 to a package 6.
6 and mounted. Next, the metal bumps of the flexible substrate 61 are pressed and heated by the bonding tool 69 from above the flexible substrate 61, and the metal bumps on the high-frequency signal and the ground wiring are used as the signal wiring of the package, and the ground wiring is used as the ground. The procedure for joining each is used. Although the materials of the metal bumps are not described in detail in these publications, solder is generally used for such a purpose.

[0009]

However, FIG.
The conventional technique shown in FIG. 8 has the following problems. First, in order to connect bumps using solder, align the solder bumps provided on one or both of the electrodes to be connected, or the electrodes with solder supplied by screen printing or plating, and apply heat and pressure. However, in this step, the molten solder is spread laterally by the applied pressure.If the electrode spacing is small, the solder spread from adjacent pads comes into contact with each other, and In this case, a short circuit occurs, and a normal connection cannot be made. The limit value depends on the size of the solder bump, but is considered to be around 120 μm. In general, compound semiconductors have high material costs, so that semiconductor elements having the smallest possible area are manufactured. For this reason, the electrode pitch of the device tends to be narrow, and some devices having a pitch of 100 μm or less have appeared. Therefore, the connection method using solder cannot deal with recent narrow-pitch semiconductor elements.

Further, as shown in FIG. 7, when a large number of semiconductor elements are flip-chip mounted on a substrate,
If even one of the many semiconductor elements has a defective element,
Since local repair work is extremely difficult, there is a problem that the entire mounting substrate must be replaced. That is, the conventional structure shown in FIG. 7 has a drawback that it is extremely difficult to perform a repair operation after being mounted once. Therefore, the yield is extremely reduced in a module in which a plurality of semiconductor elements are mounted. There are issues.

On the other hand, as shown in FIG. 8, when the flip chip is mounted on the flexible board, the electrical test is performed to determine the quality of the module, so that the entire mounting board is replaced. Has solved. However, the flexible wiring board is first positioned and mounted on the package, and then the bonding is performed by pressing and heating the metal bumps of the flexible wiring board with a bonding tool from above the flexible wiring board. Due to the use of this method, when the metal bumps of the carrier substrate and the main substrate are bonded under pressure and heat, it is conceivable that a slight misalignment may occur, resulting in mounting that does not satisfy high-frequency characteristics. , It becomes extremely difficult to perform the repair work. Also, once the bumps of the flexible wiring board that has been joined are melted again and removed, the remaining solder is removed on the flexible wiring board, and then the process of forming the bumps again, and on the board side, Similarly, in addition to the removal of the residual solder, the steps of repositioning, mounting, pressing, and heating must be performed independently of a series of mounting, which is a very complicated operation.

By the way, if a step or a discontinuity occurs on a signal transmission line, mismatching of characteristic impedance occurs, and a reflection phenomenon of a signal caused by the mismatch occurs. Therefore, in a high frequency region such as a microwave, a millimeter wave, or the like. It is known that the signal transmission characteristics deteriorate. As a countermeasure against this, conventionally, as shown in FIG.
Is provided, and the height of the transmission line is aligned on the same plane by accommodating a semiconductor element therein.
However, the method of providing a cavity and mounting a semiconductor element therein requires the provision of an opening on a mounting board in advance, which imposes restrictions on mounting due to the opening and increases the manufacturing cost of the mounting board. There were challenges.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problem, and it is an object of the present invention to provide a high-frequency circuit module which has a high mounting yield, can be repaired (repaired) by a simple operation, and is prevented from deteriorating in electrical characteristics. With the goal. It is another object of the present invention to provide a method of manufacturing a high-frequency circuit module that can easily obtain the high-frequency circuit module at a high yield.

[0014]

A first high-frequency circuit module according to the present invention comprises a semiconductor element, a carrier substrate to which the semiconductor element is bonded, and a connection using the carrier substrate and the side wall of the carrier substrate. And a main substrate connected to the carrier substrate by a portion.

In a second high-frequency circuit module according to the present invention, in the first high-frequency circuit module, the semiconductor element is bonded to the first signal line provided on the main surface of the carrier substrate, and the semiconductor element is provided on the main substrate. The second signal line and the first signal line are connected by a connecting portion using a conductive material that is softened or melted by heat.

A third high-frequency circuit module according to the present invention is the first high-frequency circuit module according to the first high-frequency circuit module, wherein the first ground line provided on the main surface of the carrier substrate and the second ground line provided on the main substrate. Are connected by a connection portion using a conductive material that is softened or melted by heat.

According to a fourth high-frequency circuit module of the present invention, in the second or third high-frequency circuit module, the signal line of the carrier substrate or the main substrate has a coplanar transmission line structure.

In a fifth high-frequency circuit module according to the present invention, in the first high-frequency circuit module, a notch having a concave cross section is formed on a side wall from the main surface side to the back surface side of the carrier substrate. The connection electrode is provided on the wall surface of the notch.

A sixth high-frequency circuit module according to the present invention is the fifth high-frequency circuit module according to the fifth high-frequency circuit module, wherein a land is formed around the recess formed by the cutout on the back surface of the carrier substrate, and the land is connected to the land. The connection region of the signal line or the ground line on the substrate has a shape that follows the outer peripheral shape of the land.

In a seventh high-frequency circuit module according to the present invention, in the first high-frequency circuit module, the semiconductor element is flip-chip bonded by solid phase diffusion bonding of gold.

An eighth high-frequency circuit module according to the present invention is the above-mentioned first high-frequency circuit module, wherein the thickness of the carrier substrate is 10 to 600 μm.

A ninth high-frequency circuit module according to the present invention is the above-mentioned first high-frequency circuit module, wherein a carrier member or a main substrate is provided with a dam member for stopping a flow of a conductive material.

According to a tenth high-frequency circuit module of the present invention, in the ninth high-frequency circuit module, the dam is formed using a metal film.

In an eleventh high-frequency circuit module according to the present invention, in the ninth high-frequency circuit module, a connection region between the second signal line provided on the main substrate and the carrier substrate is limited by the dam member. Things.

In a first method of manufacturing a high-frequency circuit module according to the present invention, a step of bonding a semiconductor element to a carrier substrate, and connecting the carrier substrate and the main substrate by a connection portion using a side wall of the carrier substrate, In this method, a step of mounting a carrier substrate on a main substrate is performed.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a perspective view of a high-frequency circuit module according to a first embodiment of the present invention, in which 1 is a bare semiconductor element cut out from a wafer, 20 is a carrier substrate, and 22 is a main surface of the carrier substrate. The first signal line formed, 23 is a first ground line formed on the main surface of the carrier substrate, 50 is the carrier substrate 20
, A second signal line 52 provided on the main substrate and transmitting a high-frequency signal, 54 a second ground line provided on the main substrate, and 25 provided on a side wall of the carrier substrate 20. A half through hole, 251, which is a cutout having a concave cross section from the main surface side to the back surface side of the carrier substrate.
252 is a connection electrode provided on the wall surface of the half through hole 25,
Reference numeral 35 denotes a conductive material that is softened or melted by heat, such as solder, for example, and the connection electrodes 251 and 252 and the conductive material 35.
Constitutes a connecting portion for connecting the carrier substrate 20 and the main substrate 50. That is, the first signal line 22 of the carrier substrate 20 and the second signal line 52 of the main substrate 50 via the connection electrode 251, or the first ground line 23 of the carrier substrate and the first signal line 52 of the main substrate 50 via the connection electrode 252. Second ground line 54
Are connected using a conductive material 35 to mount the carrier substrate on the main substrate. Reference numerals 27 and 57 denote resists (weir members) for stopping the flow of the conductive material and preventing the spread of the conductive material.

FIG. 2 is a sectional view taken along the line II in FIG. 1. In FIG. 2, reference numeral 10 denotes a connection electrode with an external circuit formed on the semiconductor element, and reference numeral 15 denotes a bump, which is formed of, for example, gold. Is flip-chip bonded to the first signal line 22 of the carrier substrate 20 by solid-phase diffusion bonding. Since solid-phase diffusion bonding is used, the bonding is strong and is preferable. Reference numeral 29 denotes a ground electrode formed on the back surface of the carrier substrate.

FIGS. 3A and 3B are explanatory views for explaining the structure of the carrier substrate. FIG. 3A shows the surface of the carrier substrate on which the semiconductor elements are mounted, and FIG. 3B shows the surface on which the semiconductor elements are mounted. It is the back of. Reference numeral 30 denotes an electrode pad portion for mounting a semiconductor element on the first signal line 22, and 31 denotes a first signal line.
An electrode pad portion 36 for mounting a semiconductor element on the ground line 23 is a land formed around a recess formed by the through hole 25 on the back surface of the carrier substrate.

As shown in FIGS.
The upper first signal line 22 forms a transmission line together with the first ground line 23, and the carrier substrate 20 and the semiconductor element 1 are flip-chip bonded. Carrier substrate 2
The connection electrodes 251 and 252 corresponding to the transmission line structure on the main surface are provided on the half through-hole wall provided on the side wall of No. 0 so as to be connected to the line on the main surface. On the other hand, a second signal line 22 and a second ground line 54 are provided on the main substrate 50 on which the carrier substrate is mounted on the main substrate 50 for secondary mounting. Here, in the high-frequency circuit module according to the first embodiment of the present invention, the first signal line 22 and the second signal line 52 are connected via the connection electrode 251, but are softened or melted by heat. Since the carrier substrate and the main substrate signal line are connected in the form of a coplanar transmission line at the connection portion using the conductive material 35 on the side wall, even if there is a step between the carrier substrate and the main substrate signal line, the high frequency Signal reflection is suppressed, and deterioration of electrical characteristics is prevented.

When one or more of the carrier substrates 20 shown in the figure are mounted on the main substrate 50 by connecting portions using a conductive material which is softened or melted by heat such as solder, a high frequency circuit module is formed by heating. Repair work after mounting is easy, and production can be performed with high productivity while maintaining a high mounting yield.

Although the figure shows an example in which the carrier line structure of the carrier substrate or the main substrate is a coplanar transmission line structure, a microstrip transmission line structure often used as a transmission line of a high-frequency signal may be employed.

Further, as shown in the figure, a first ground line 23 provided on the carrier substrate and a second ground line 54 provided on the main substrate are provided on the side wall of the carrier substrate.
The connection using the conductive material 35 through the connection electrode 252 connected to the first ground line has an effect that the mounting of the carrier substrate on the main substrate becomes more robust.

Further, as shown in the figure, by providing a dam member (for example, a solder resist) for stopping the flow of the conductive material on the carrier substrate or the main substrate, the conductive material flows on the surface of the carrier substrate or the main substrate. In addition, the amount of the conductive material at the connection portion becomes insufficient due to the spread of the wetted portion, and the strength of the connection portion is reduced, and the electrical characteristics can be prevented from being reduced by flowing into the lower surface of the semiconductor element. When the dam member is formed using a metal film, it is possible to prevent the signal transmissivity of the transmission line from being impaired. In addition, when the connection region of the main substrate with the carrier substrate is limited by a damping material such as a solder resist, there is an effect that highly accurate mounting is possible.

In the figure, the connection electrodes are formed on the half through-holes of the carrier substrate.
The one used for the connection of the ground line is distinguished from 252. Further, the connection area of the second signal line of the main board with the carrier board is preferably formed in accordance with the outer peripheral shape of the land 36 so that electric loss due to connection can be reduced to a minimum. It is formed as a semicircular signal electrode pad corresponding to the outer shape of the land 36 of the split through hole 25.

The thickness of the carrier substrate is 10 to 600 μm
However, even if there is a step between the main substrate and the carrier substrate, the high frequency characteristics are not impaired. If it is less than 10 μm, it is too thin to handle, and if it exceeds 600 μm, the reflection loss of the line increases and the high frequency characteristics deteriorate. . LTCC (low temperature fired glass ceramic substrate) as carrier substrate
The conductive material on the carrier substrate using copper, silver, silver-palladium, silver-platinum low-conductivity metal is used, and those whose surfaces of these conductive materials are plated with gold, Alternatively, a printed wiring board using an organic material is used as the carrier substrate, and the conductor material on the substrate is made of copper and the surface thereof may be plated with gold. As compared with the conductor wiring using a metal material to be obtained, a conductor loss is reduced and a low loss carrier substrate is obtained. Also, for example, as a carrier substrate, a polyimide substrate-based flexible wiring board,
A thin wiring board structure based on a glass epoxy base can also be used. As the main substrate, a ceramic substrate is used, but a printed wiring board using an organic material can also be used as long as the value shows no problem with loss or the like.

Embodiment 2 FIG. 4 is an explanatory view for explaining a method of manufacturing the high-frequency circuit module according to the second embodiment of the present invention. In the figure, reference numeral 53 denotes a second signal line 52 provided on the main substrate 50. The electrode pad portion 55 used for connection to the first signal line 22 is the first ground line 23 of the second ground line 54 provided on the main substrate.
This is an electrode pad portion used for connection with the electrode pad.

That is, the semiconductor element 1 is, for example, flip-chip bonded to the first signal line 22 provided on the main surface of the carrier substrate 20. On the other hand, a second signal line 52 is provided on the main substrate. The carrier substrate is mounted on the main substrate with the connection region between the first signal line 22 and the first signal electrode of the second signal line 52 facing each other. In addition, connection electrodes 251 and 252 are provided on the side wall. A conductive material that is softened or melted by heat is supplied, and the carrier substrate or the main substrate is heated and cooled to manufacture the high-frequency circuit module according to the present embodiment. In addition, since the carrier substrate is mounted on the main substrate using the side wall, deterioration of electric characteristics is small and manufacture is easy. The above manufacturing method has a good yield and is easy to manufacture. Further, when a material that is softened or melted by heat is used as the conductive material, it can be manufactured with higher yield. Further, as shown in the following embodiment, the conductive material may be provided on the signal electrode pad 53 or the ground electrode pad 55 in advance.

[0038]

[Embodiment 1] Hereinafter, description will be made with reference to FIGS. (1) Ga having a frequency band up to about 30 GHz
An As-made FET (field effect transistor) 1 is prepared, and a gold bump 15 is provided on the pad electrode 10. That is, the outer dimensions of the GaAs FET are 0.4 × 0.
It is a 5 mm rectangle with a thickness of 0.1 mm. A plurality of gold pad electrodes 10 having a thickness of about 1 μm are provided on the circuit surface.
As a first step, a bump 15 made of gold is provided on the pad electrode 10. The projecting bumps 15 are formed by using an ultrasonic wire bonding apparatus commonly called a ball bonder. The condition for forming the projecting bumps 15 is a diameter of 20.
Using a gold wire of μm, the ultrasonic energy was set to 0.
At 2 W, the bonding time is 25 milliseconds. GaAs FET
Is maintained on the stage at a set temperature of 250 ° C. As a result, a gold bump 15 having a diameter of 70 μm and an average height of 65 μm can be formed. The protruding bumps 15 are formed by vertically breaking the gold wire that has been joined by the ultrasonic bonding apparatus.

(2) A carrier substrate on which a GaAs FET is mounted is prepared. That is, the carrier substrate 20 is an alumina substrate having conductor wiring, and the substrate material is high-grade alumina having a purity of 99.5%. The outer dimensions of the carrier substrate 20 are a rectangle of 3.5 × 2.5 mm and a thickness of 0.4.
mm. The substrate having an average roughness of 0.1 μm or less was used. On the upper surface of the carrier substrate 20, the first signal line is provided with an electrode pad 3 for mounting the semiconductor element 1.
0, an electrode pad 31 is provided on the first ground line.

On the side wall of the carrier substrate 20, the following electrodes used for connecting the carrier substrate 20 and the main substrate 50 are formed. First, the main substrate 50 is connected to the connection electrodes 251 formed on the wall surfaces of the plurality of half-through holes 25.
The second signal line 52 of the coplanar transmission line for the high frequency signal is connected to the signal line 22 on the carrier substrate.
Further, the connection electrodes 252 formed on the wall surfaces of the plurality of half-through holes 25 form the second ground line 54 of the coplanar transmission line for the high frequency signal of the main substrate 50 and the first ground line 23 on the carrier substrate. Are connected using a conductive material, and are used as ground electrodes for forming an electrically strong ground. On the rear surface of the carrier substrate, a ground electrode 29 called back metallization is provided on almost the entire surface. The above conductor wiring is the minimum line and space 6
It is formed with an accuracy of 0 μm / 60 μm. The conductor wiring has a multi-layer structure made of metal, and the structure is Ti
/ Pd / Au. The thicknesses of the conductors are respectively 700 ° / 1300 ° / 1 μm.

(3) GaAs F on the carrier substrate 20
ET1 is flip-chip bonded. At the time of joining the carrier substrate 20 and the GaAs FET, an alignment function by image processing is required to accurately align the electrode pad portions 30 and 31 on the carrier substrate with the gold protruding electrodes 15 on the GaAs FET. A flip chip bonder (mounting device) provided with Carrier substrate and GaAs FE
T is bonded by a gold-gold solid phase diffusion bonding method. The heating and pressing tool attached to the flip chip bonder has a vacuum suction hole, and the GaAs FET is directly suctioned to the tool and heated and pressed. The maximum applied load per bump is 11
0 g. The temperature at the time of pressurization is 290 ° C. on the carrier substrate side and 290 ° C. on the GaAs FET side.
The pressurization time was 12 seconds. Carrier substrate and GaAs
Since the FET is firmly bonded only by gold-gold solid phase diffusion bonding, reinforcement (underfill) with resin or the like is not required.

(4) A main substrate 50 on which a carrier substrate on which a GaAs FET is mounted is prepared. That is, the main substrate 50 is an alumina substrate having conductor wiring, the substrate material is high-grade alumina having a purity of 99.5%, the outer dimensions are a rectangle of 50 × 70 mm, and the thickness is 0.6 mm. . The following electrodes for mounting a carrier substrate on which a GaAs FET is mounted are formed on the surface of the main substrate. That is, the first signal line 52 of the carrier substrate of the second signal line 52 of the main substrate, which is a coplanar transmission line for high-frequency signals.
A signal electrode pad 53 that is a connection region with the signal line of
A plurality of ground electrode pads 55 used as ground electrodes of the second ground line 54. The plurality of ground electrode pads 55 are formed in the openings of the main substrate solder resist on the main substrate ground line to form an electrically strong ground conductor. A ground electrode called back metallization is provided on almost the entire back surface of the main substrate 50, and is connected to the main substrate ground line by a plurality of through-holes (not shown). The conductor wiring of the main board is formed with a minimum line and space accuracy of 60 μm / 60 μm. The conductor wiring has a multi-layered structure made of metal, and its configuration is laminated in the order of Ti / Pd / Au from the bottom layer. Conductor thickness is 700 は / 1300Å / 1μ respectively
m.

On the upper surface of the main substrate, a carrier substrate on which a GaAs FET is mounted is precisely solder-mounted.
Although the solder resist 57 is formed, the following operation is required for the solder resist. That is, in the high-frequency circuit module of the present invention, the solder is melted and G
A carrier substrate on which an aAs FET is mounted is mounted on a main substrate. That is, since the soldering is performed on the gold electrode and the gold-plated wiring, there is a problem of a wet spreading phenomenon in which the molten solder flows along the electrode and the wiring. In order to prevent the flow of the molten solder, it is necessary to provide a dam (a kind of dam) called a solder resist. As a material that achieves such a purpose, there is a method of forming a dam using a dielectric such as a resin. However, when the target is a high-frequency signal, it is not preferable in terms of electrical characteristics to use a dielectric solder resist made of resin or the like, and it is advantageous to attenuate the high-frequency signal by seeking a thin metal film to prevent the flow of solder. Work on. The reason is that in the case of a dielectric, power loss called dielectric loss occurs. This loss is caused by the relative permittivity (εr) and the dielectric loss tangent (tan) of the dielectric.
δ), and this problem can be avoided by using a metal. As described above, by using a dam member (solder resist) made of a metal film, even when the electrodes are placed very close to each other,
This is useful for high-density mounting because there is no possibility that molten metal such as solder flows out and short-circuits occur between adjacent electrodes.

(5) GaAs is formed on the main substrate 50 made of alumina.
The carrier substrate 20 on which the FET 1 manufactured is mounted is aligned. First, the carrier substrate 20 is positioned so that the connection electrodes of the carrier substrate are located on the signal electrode pads on the main substrate 50. In order to accurately align the carrier substrate on which the GaAs FET is mounted with the main substrate, a flip chip bonder (mounting device) having the above-described alignment function by image processing is used. Since the upper surface of the carrier substrate on which the GaAs FET is mounted is not flat due to the presence of the GaAs FET, a special gripping jig different from the above-described heating and pressing tool having a vacuum suction hole is used for handling the carrier substrate. Was used. In this gripping jig,
This is a tool of the type that sandwiches the side surface of the carrier substrate on which the GaAs FET is mounted. The tool incorporates a ceramic heater capable of rapidly increasing the temperature.

(6) The carrier substrate 20 and the main substrate 50 are joined by a conductive material. Solder is used as a conductive material, and a lead-tin eutectic solder paste is supplied on the main substrate in advance by a screen printing method. For heating the main substrate, a heating mechanism attached to the flip chip bonder was used. This heating mechanism is a heater that is maintained at a set temperature called a constant heat method, and is used to give a temperature at which solder does not melt (base temperature) to the main substrate. At the time of solder joining, by applying transient heat supplied from the gripping jig to this base temperature, a temperature environment exceeding the melting temperature (183 ° C.) was given to the solder. The set temperature on the main substrate side was 150 ° C., and the heating time was 15 seconds. Cooling after the completion of the solder joining was performed by air blowing. According to this mounting method, since the solder does not melt only at the base temperature for heating the main substrate, the GaAs FET
By applying local heating only to the carrier substrate on which is mounted, solder bonding at a desired portion can be performed. In addition, in a carrier substrate on which a GaAs FET already mounted with solder is mounted, there is no displacement due to re-melting of the solder. As described above, it is possible to mount a carrier substrate on which a plurality of GaAs FETs are mounted on one main substrate. After the completion of the soldering, the flux at the time of the soldering is washed as necessary to complete the high-frequency circuit module. As described above, the solder is supplied to the main board in advance, but after the alignment, the thread solder or the pellet solder may be supplied, so that the solder can be prevented from leaking.

The high-frequency electrical characteristics of the high-frequency circuit module manufactured as described above were measured and evaluated. FIG.
Is a characteristic diagram showing a conventional method of directly mounting a flip chip on an alumina main substrate and a high-frequency electric characteristic of the high-frequency circuit module of the present embodiment. The horizontal axis represents frequency, and the vertical axis represents line reflection loss ( S11) and the passage loss (S21).
In the figure, S11 and S21 are the reflection loss and the passage loss of the high-frequency circuit module of the present embodiment, respectively, and S11h and S21h are the reflection loss and the passage loss of the frequency circuit module obtained by the conventional mounting method, respectively. As shown in the figure,
Compared with the conventional methods S11h and S21h in which flip-chip mounting is directly performed on the main substrate made of alumina, the high-frequency circuit modules S11 and S21 of the present embodiment slightly deteriorate in characteristics, but there is a remarkable difference up to 30 GHz. Not
It has been clarified that the high-frequency characteristics do not significantly deteriorate even when the mounting method according to the present invention is adopted. The reason for this is that, in the present invention, the carrier substrate on which the GaAs FET is mounted is connected using the side wall even though the carrier substrate is mounted with a step between itself and the main substrate signal line. Is suppressed, and the electrical characteristics are not degraded. In other words, even if there is a physical step in the signal transmission line, it is possible to provide practical use if a design that can suppress the mismatch of the characteristic impedance to a practically negligible level is performed. As a result of repeated experiments, it was found that if the value of this step is 600 μm or less in terms of the thickness of the carrier substrate, it can be practically used in the frequency range of FIG.

According to the present invention, a carrier substrate on which a GaAs FET is mounted is surface-mounted on a main substrate by using a conductive material which is softened or melted by heat. The use of a tin-based eutectic solder makes it easy to repair after mounting. Further, as the conductive material, a thermoplastic resin containing a metal filler such as silver or a thermoplastic anisotropic conductive film can be used. Further, in the present invention, since the above-mentioned conductive material is used, the GaAs F
If it becomes necessary to replace the ET,
The solder connection part of the carrier substrate on which the
By performing local heating with a soldering iron, heat tool, hot air, etc., other GaAs FE
Only the defective portion can be independently removed from the carrier substrate on which the T is mounted, and repair can be performed by mounting the carrier substrate on which a new GaAs FET is mounted. This allows
Even if a high-frequency circuit module shows nonstandard electrical characteristics, it can be easily repaired and treated as a new high-frequency circuit module, improving production yield and reducing product cost. Become.

In the embodiment described above, the GaAs F
ET was flip-chip mounted using gold-gold solid-state diffusion bonding, and the structure without underfill was explained. However, if the high-frequency characteristics are not so important, the underfill can be used to improve moisture resistance and mechanical properties. The improvement of the target strength can be expected. As a material for the underfill, a thermosetting or photocuring or thermoplastic resin material can be used.

Embodiment 2 FIG. As the semiconductor element, a GaAs FET having a frequency band of about 30 GHz, which is the same as that used in the first embodiment, is used. An LTCC substrate (low-temperature fired glass ceramic substrate) is used instead of the alumina carrier substrate used as the carrier substrate in the first embodiment. The feature of the LTCC substrate is that the firing temperature of the ceramic can be lowered, so the conductive material on the carrier substrate is copper,
It is possible to use a metal having low conductivity such as silver, silver-palladium, and silver-platinum. As a result, there is an effect that a low-loss carrier substrate with reduced conductor loss can be realized as compared with a conductor wiring using a high-resistance metal material used for an ordinary alumina substrate.

That is, the carrier substrate and the main substrate are LTCC substrates having conductor wiring. The outer dimensions of the carrier substrate are 3.5 × 2.5 mm rectangles and the thickness is 0.28 mm
It is. The outer dimensions of the main board are a rectangle of 50 × 70 mm, and the thickness is 0.56 mm. The above conductor wiring is formed with a minimum line and space accuracy of 60 μm / 60 μm. The conductor wiring has a multi-layered structure made of metal, and its configuration is laminated in the order of AgPd / Ni / Au from the bottom layer. The thickness of each conductor is 10 μm / 3 μm / 1
μm.

The carrier substrate and the main substrate were prepared, mounted in the same manner as in Example 1, a high-frequency circuit module was manufactured, and high-frequency electric characteristics were measured. FIG. 6 is a characteristic diagram showing high-frequency electrical characteristics of the high-frequency circuit module of the present embodiment. The horizontal axis represents frequency, and the vertical axis represents reflection loss (S11) and transmission loss (S21) of the line. In the figure, S11a and S21a are reflection loss and passage loss of a high-frequency circuit module obtained by solder mounting an alumina carrier substrate flip-chip mounted on an alumina main substrate, respectively.
S21b is the reflection loss and the passage loss of the frequency circuit module obtained by soldering the flip-chip mounted LTCC carrier board to the LTCC main board. As shown in the figure, the loss was not changed as compared with the alumina substrate, and it was found that the LTCC substrate can be sufficiently used as the carrier substrate of the present invention.

Embodiment 3 FIG. As the semiconductor element, a GaAs FET having a frequency band of about 30 GHz, which is the same as that used in the above embodiment, is used. On the carrier substrate,
Instead of the alumina carrier substrate used as the carrier substrate in the first embodiment, a substrate using an organic printed wiring board is used. As a substrate material, a substrate made of a BT resin (bismaleimide / triazine resin) having low dielectric loss and excellent high frequency characteristics is used.

The carrier substrate has a rectangular shape of 5 mm × 5 mm, has an electrolytic copper foil of 12 μm in thickness, and has a substrate thickness of 6 mm.
00 μm. Minimum line and space 6 on board
A conductor wiring pattern of 0 μm / 60 μm is formed. The conductor wiring and the electrode pads are electrolessly plated by nickel plating of 4 μm thickness and then gold plating of 0.8 μm thickness. The carrier substrate and the same alumina main substrate as in Example 1 were prepared, mounted in the same manner as in Example 1, a high-frequency circuit module was manufactured, and high-frequency electrical characteristics were measured. The results are shown in FIG. In the figure, S11c, S2
1c is a reflection loss and a transmission loss of a high-frequency circuit module obtained by solder-mounting a carrier substrate made of an organic printed wiring board, each of which is flip-chip mounted, on an alumina main substrate. S11b, S21b are LTCC carrier substrates, each of which is flip-chip mounted. Is a reflection loss and a transmission loss of the frequency circuit module obtained by soldering the frequency circuit module to the LTCC main board. As shown in the figure, although the loss is increased as compared with the ceramic substrates described in Examples 1 and 2, it can be seen that if the use is limited, it can be sufficiently used as a carrier substrate.

[0054]

According to the first high-frequency circuit module of the present invention, a semiconductor device, a carrier substrate to which the semiconductor device is bonded, and the carrier substrate are mounted, and the carrier substrate is connected by a connecting portion using a side wall of the carrier substrate. The main substrate connected to the substrate has an effect that deterioration of electrical characteristics is prevented and the yield is high.

A second high-frequency circuit module according to the present invention comprises:
In the first high-frequency circuit module, the semiconductor element is joined to a first signal line provided on the main surface of the carrier substrate, and the second signal line provided on the main substrate and the first signal line are: It is connected by a connecting portion using a conductive material that is softened or melted by heat, and has an effect that repair work is easy.

A third high-frequency circuit module according to the present invention comprises:
In the first high-frequency circuit module, the first ground line provided on the main surface of the carrier substrate and the second ground line provided on the main substrate are connected using a conductive material softened or melted by heat. The parts are connected by the unit, and there is an effect that the mounting is robust.

A fourth high-frequency circuit module according to the present invention comprises:
In the second or third high-frequency circuit module,
The signal line of the carrier substrate or the main substrate has a coplanar transmission line structure, and has an effect that deterioration of electrical characteristics can be prevented.

The fifth high-frequency circuit module according to the present invention comprises:
In the first high-frequency circuit module, the side wall includes:
A cutout having a concave section is formed from the main surface side to the rear surface side of the carrier substrate, and a connection electrode is provided on the cutout wall surface. This has an effect that high-density mounting is possible.

A sixth high-frequency circuit module according to the present invention comprises:
In the fifth high-frequency circuit module, a land is formed around the concave portion formed by the cutout on the back surface of the carrier substrate, and the shape of the connection area of the signal line or the ground line of the main substrate connected to the land is as described above. It has a shape that follows the outer peripheral shape of the land, and has the effect of minimizing electrical loss due to connection.

The seventh high-frequency circuit module according to the present invention comprises:
In the first high-frequency circuit module, the semiconductor element is flip-chip bonded by solid-state diffusion bonding of gold, and has an effect that bonding is strong and excellent in high-frequency characteristics.

An eighth high-frequency circuit module according to the present invention comprises:
In the first high-frequency circuit module, the thickness of the carrier substrate is 10 to 600 μm, and there is an effect that high-frequency characteristics are not impaired.

A ninth high-frequency circuit module according to the present invention comprises:
In the first high-frequency circuit module, the carrier substrate or the main substrate is provided with a dam member for stopping the flow of the conductive material, and there is an effect that high-density and high-precision mounting can be performed.

According to a tenth high-frequency circuit module of the present invention, in the ninth high-frequency circuit module described above, the dam member is formed using a metal film, so that it is possible to prevent signal impairment from being impaired. There is.

An eleventh high-frequency circuit module according to the present invention is the ninth high-frequency circuit module according to the above-mentioned ninth high-frequency circuit module, wherein a connection region of the second signal line provided on the main substrate with the carrier substrate is limited by the dam member. Therefore, there is an effect that high-density and high-precision mounting can be performed.

In a first method of manufacturing a high-frequency circuit module according to the present invention, a step of bonding a semiconductor element to a carrier substrate, and connecting the carrier substrate and the main substrate by a connecting portion using a side wall of the carrier substrate, The method of performing the step of mounting the carrier substrate on the main substrate has an effect that the yield is high and the manufacturing is easy.

[Brief description of the drawings]

FIG. 1 is a perspective view of a high-frequency circuit module according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II in FIG.

FIG. 3 is an explanatory diagram illustrating a structure of a carrier substrate according to the high-frequency circuit module according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram illustrating a method for manufacturing a high-frequency circuit module according to a second embodiment of the present invention.

FIG. 5 is a characteristic diagram showing high-frequency electrical characteristics of the conventional system and the high-frequency circuit module of the present embodiment.

FIG. 6 is a characteristic diagram illustrating high-frequency electrical characteristics of the high-frequency circuit module according to the present embodiment.

FIG. 7 is an explanatory view showing a state in which a conventional semiconductor chip is flip-chip mounted on a substrate.

FIG. 8 is a cross-sectional view illustrating a state in which a conventional semiconductor element is mounted on a package and mounted by pressing.

[Explanation of symbols]

Reference Signs List 1 semiconductor element, 20 carrier substrate, 22 first signal line, 23 first ground line, 36 land, 50
Main board, 52 second signal line, 54 second ground line, 25 notch (half through hole), 251,
252 connection electrode, 35 conductive material, 53 electrode pad portion used for connection to the first signal line, 55 electrode pad portion used for connection to the first ground line.

Claims (12)

[Claims] 1. A high-frequency circuit comprising: a semiconductor element; a carrier substrate to which the semiconductor element is bonded; and a main substrate mounted with the carrier substrate and connected to the carrier substrate by a connection portion using a side wall of the carrier substrate. module. 2. The semiconductor device is joined to a first signal line provided on a main surface of a carrier substrate, and the second signal line provided on the main substrate and the first signal line are softened or damaged by heat. The high-frequency circuit module according to claim 1, wherein the high-frequency circuit module is connected by a connection portion using a conductive material that melts. 3. A first ground line provided on a main surface of a carrier substrate and a second ground line provided on a main substrate are connected by a connection portion using a conductive material softened or melted by heat. The high-frequency circuit module according to claim 1, wherein: 4. The high-frequency circuit module according to claim 2, wherein the signal line of the carrier substrate or the main substrate has a coplanar transmission line structure. 5. A notch having a concave cross section from a main surface side to a back surface side of a carrier substrate is formed on a side wall, and a connection electrode is provided on a wall surface of the notch portion. Item 2. The high-frequency circuit module according to Item 1. 6. A land is formed on the back surface of the carrier substrate around a recess formed by the notch, and a shape of a connection area of the signal line or the ground line of the main substrate connected to the land is an outer peripheral shape of the land. The high-frequency circuit module according to claim 5, wherein the high-frequency circuit module has a shape that conforms to the shape of the high-frequency circuit module. 7. The semiconductor device according to claim 1, wherein the semiconductor elements are flip-chip bonded by solid phase diffusion bonding of gold.
2. The high-frequency circuit module according to item 1. 8. The carrier substrate has a thickness of 10 to 600 μm.
The high-frequency circuit module according to claim 1, wherein 9. The high-frequency circuit module according to claim 1, wherein the carrier substrate or the main substrate is provided with a dam member for stopping a flow of the conductive material. 10. The high-frequency circuit module according to claim 9, wherein the dam member is formed using a metal film. 11. The high-frequency circuit module according to claim 9, wherein the connection region of the second signal line provided on the main substrate with the carrier substrate is limited by the dam member. 12. A high-frequency circuit for performing a step of joining a semiconductor element to a carrier substrate and a step of connecting the carrier substrate and the main substrate by a connection portion using a side wall of the carrier substrate and mounting the carrier substrate on the main substrate. Module manufacturing method.