JP2790272B2 - High frequency power amplifier module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-frequency power amplifier module comprising a high-frequency power amplifier circuit using a semiconductor element for power amplification and a chip component.

[0002]

2. Description of the Related Art In recent years, with the spread of communication devices such as mobile phones, demand for microwave band high frequency power amplifier modules has been increasing. The high-frequency power amplification module is, specifically, a power amplification semiconductor element (hereinafter, referred to as “power FET” as an example thereof) and a chip such as a resistor and a capacitor on a printed circuit board on which a microstrip line is formed. A high-frequency power amplifier on which components are mounted.

A high-frequency power amplifier module is used in a transmitting section of a mobile communication device such as a mobile phone, and its performance such as shape and efficiency is a main component for determining the size of the communication device and the length of a talk time. . Furthermore, the high-frequency power amplification module is the component that consumes the most power among components used in communication devices, and it is important to improve the heat dissipation. As a specific method for improving heat dissipation, a configuration is generally adopted in which a printed circuit board constituting a high-frequency power amplification module is soldered on a metal heat dissipation plate, and the entire high-frequency power amplification module is covered with a metal cap. I have.

FIGS. 9A and 9B are a cross-sectional view and an exploded perspective view showing an example of the configuration of a high-frequency power amplifier module according to the prior art. More specifically, FIG.
The cross-sectional structure taken along line 9A-9A 'shown in FIG.

In the illustrated high-frequency power amplifier module, a printed circuit board 106 on which circuit elements are mounted is soldered on a heat sink 101. In particular, among the circuit elements used, the power FET 107 in the output stage having a large output power is directly placed on the heat radiating plate 101 through the through hole 113 provided in the printed circuit board 106 in order to enhance its heat radiation. Soldered. In order to improve the heat radiation characteristics of the high frequency power amplifier module, a heat sink 1
01 needs to be relatively thick.

The heat radiating plate 101 is connected to the printed circuit board 10.
6 is bonded to a metal cap 105 provided so as to cover a circuit element and the like mounted on 6. Specifically, the joining of the metal cap 105 and the heat sink 101 is performed by engaging the hook 123 of the metal cap 105 with the groove 124 provided on the bottom surface of the heat sink 101.

[0007] When the use in the microwave band is considered, the bonding state between the metal cap 105 and the heat sink 101 becomes important. If the bonding between them is poor, not only does the heat dissipation deteriorate, but also the potential of each part of the metal cap 105 is slightly different from the ground potential, which adversely affects the high-frequency operation characteristics of the high-frequency power amplifier module. For this reason, in the configuration of the high-frequency power amplifier module as shown in FIGS. 9A and 9B, high processing accuracy of the heat sink 101 is required.

The processing of the heat radiating plate 101 can be performed, for example, by cutting or pressing. However, in general, cutting is excellent in terms of processing accuracy, but has high production cost and is not suitable for mass production. On the other hand, press working using a mold is excellent in mass productivity but inferior in working accuracy. Therefore, if it is attempted to increase the processing accuracy of the heat sink by pressing, the manufacturing cost becomes extremely high.

FIGS. 10 (a) and 10 (b) are a cross-sectional view and an exploded perspective view showing an example of the configuration of a high-frequency power amplifier module having a medium-level output (specifically, an output of about 1 W class) according to the prior art. . More specifically, FIG.
The cross-sectional structure taken along line 10A-10A ′ shown in FIG.

In the illustrated high-frequency power amplifier module, a printed circuit board 106 on which circuit elements are mounted is soldered on a heat sink 101. In particular, among the circuit elements used, the power FET 107 in the output stage having a large output power is directly placed on the heat radiating plate 101 through the through hole 113 provided in the printed circuit board 106 in order to enhance its heat radiation. Soldered. In order to improve the heat radiation characteristics of the high frequency power amplifier module, a heat sink 1
01 needs to be relatively thick.

The heat radiating plate 101 is connected to the printed circuit board 10.
6 is bonded to a metal cap 105 provided so as to cover a circuit element and the like mounted on 6. Specifically, the joining of the metal cap 105 and the heat radiating plate 101 is performed by engaging the convex portion 112 provided on the bent portion 111 of the metal cap 105 with the concave portion 109 provided on the claw portion 108 of the heat radiating plate 101. ing. Further, the bent portion 111 of the metal cap 105 is
Is in contact with

As the heat radiating plate 101, a plate obtained by processing a thin flat plate having a thickness of about 0.3 mm is typically used. In a high-frequency power amplification module having an output of about 1 W class, a sufficient heat radiation effect can be obtained even with the heat radiation plate 101 having such a thickness. However, in view of the use of the high-frequency power amplifier module at a higher power and the improvement of the component mounting density accompanying the progress of miniaturization, it is required to further improve the heat radiation.

In order to improve heat dissipation, the heat sink 101
It is effective to increase the thickness of the heat radiation plate 101, but it is difficult to increase the heat radiation effect by increasing the thickness of the heat radiation plate 101 in the configuration shown in FIGS. 10 (a) and 10 (b). The first reason is that the thickness of the heat radiating plate 101 is limited because the bending process of the claw portion 108 becomes difficult when the heat radiating plate 101 is thick. Second, even if the thickness is within the range in which the bending can be performed, the thicker the claw portion 108, the larger the overall size of the high-frequency power amplifier module, which contradicts the demand for achieving miniaturization. .

[0014]

As communication devices become smaller, it is necessary to reduce the size of the high-frequency power amplifier module contained therein, and it is necessary to improve the heat radiation. However, in the conventional configuration shown in FIGS. 9A and 9B, the processing accuracy of the heat sink 101 greatly affects the high-frequency operation characteristics of the high-frequency power amplifier module, and exhibits stable operation characteristics despite its small size. Mass production of high frequency power amplifier modules is difficult. Further, in the conventional configuration shown in FIGS. 10A and 10B, it is difficult to increase the thickness of the heat radiating plate 101 to enhance the heat radiating effect due to the workability and size of the heat radiating plate 101.

As described above, with the conventional configuration, it is impossible to mass-produce a high-frequency power amplifier module having stable operation characteristics while satisfying all demands such as miniaturization and improvement of heat dissipation.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a mass-producible high-frequency power amplifier module having a small size, excellent heat dissipation, and stable operation characteristics. ,.

[0017]

According to the present invention, there is provided a high-frequency power amplifier module comprising: a heat radiating portion; a printed circuit board fixed to the heat radiating portion; a power amplifying semiconductor element mounted on the printed circuit board; It has. The heat radiating portion is composed of a plurality of heat radiating plates, and the plurality of heat radiating plates include at least a lowermost first heat radiating plate and a second heat radiating plate fixed on the first heat radiating plate. And the first heat sink is bonded to the cap. With these, the above object is achieved.

Preferably, the second radiating plate is provided with the first radiating plate.
Thicker than the heat sink.

Preferably, the first radiator plate is made of a material having a spring property, and the second radiator plate is made of a material having a high thermal conductivity.

In one embodiment, a concave portion is formed on a surface of the second heat sink at a position corresponding to a mounting position of the power amplifying semiconductor element.

In another embodiment, the second radiator plate includes:
A through hole is provided.

In still another embodiment, a groove is formed at an end of the second heat sink.

In still another embodiment, a side portion is chamfered on at least a surface of the second heat radiating plate on a side fixed to the first heat radiating plate.

According to another aspect of the present invention, a high-frequency power amplifier module includes a heat radiating portion including a plurality of heat radiating plates, a printed circuit board fixed to the heat radiating portion, and a power amplifying device mounted on the printed circuit board. A semiconductor element, and the printed board, and a heat sink fixed to the printed board among the plurality of heat sinks are provided with a common through-hole, thereby achieving the above object. Achieved.

According to still another aspect of the present invention, a high-frequency power amplifier module includes a heat radiator, a printed circuit board fixed to the heat radiator, a power amplifying semiconductor element mounted on the printed circuit board, and a cap. And a projection is formed on each of the heat radiating portion and the cap,
The bottom surfaces of the projections are located at the same height as each other, thereby achieving the above object.

Preferably, the heat radiating section includes a plurality of heat radiating plates.

According to still another aspect of the present invention, a high-frequency power amplification module includes a heat radiating portion, a printed circuit board fixed to the heat radiating portion, and a power amplifying semiconductor element mounted on the printed circuit board. The printed circuit board is provided with a through-hole, and a projection used for positioning the semiconductor element for power amplification when mounting is provided toward the through-hole. Is achieved.

Preferably, the heat radiating portion includes a plurality of heat radiating plates.

According to still another aspect of the present invention, a high-frequency power amplifier module includes a heat sink, a printed board fixed to the heat sink, and a power amplifying semiconductor element mounted on the printed board. A concave portion is formed on the surface of the heat sink at a location corresponding to the mounting location of the power amplifying semiconductor element, thereby achieving the above object.

Hereinafter, the operation will be described.

The heat radiating portion included in the high-frequency power amplifier module is constituted by a plurality of heat radiating plates, of which the first radiating plate is formed of a material having a high spring property and is joined to the metal cap. The radiator plate is made of a material having a large specific heat and an excellent thermal conductivity with emphasis on improvement of heat radiation. With this configuration, the first heat sink having high spring properties can be reliably joined to the metal cap, and stable high-frequency operation characteristics can be obtained. Further, by increasing the thickness of the second heat sink, heat radiation can be improved without increasing the overall size of the high-frequency power amplifier module.

Further, according to the present invention, protrusions are formed on the heat sink and the metal cap, and each of the protrusions is soldered to a ground potential when the high-frequency power amplifier module is mounted. With this configuration, the metal cap is reliably grounded, and stable high-frequency operation characteristics can be obtained. Further, the heat conduction from the heat radiating plate to the metal cap is improved, and the heat radiating property is improved.

Further, the heat radiating portion is constituted by a plurality of heat radiating plates, and the heat radiating plate to be soldered to the printed circuit board is provided with a common through hole with the printed circuit board. Solder pool, power FET
Thus, reliable soldering can be obtained between the power amplifying semiconductor element and the heat sink. Thereby, heat dissipation is improved.

Further, when a through hole is provided in a printed circuit board included in the high-frequency power amplifier module, a portion of the printed circuit board corresponding to at least one side of the through hole is removed to form a through hole having at least one open side. As a result, the overall size of the high-frequency power amplifier module can be reduced. Further, by forming the projections at the portion where the printed circuit board has been removed, the positioning of the power FET can be reliably fixed at a predetermined position in the assembly process. This suppresses variations in the high-frequency operation characteristics of the high-frequency power amplifier module.

By forming the heat radiating portion with a plurality of heat radiating plates and providing through holes in the heat radiating plate to be soldered to the printed circuit board, the melted solder flows evenly and the soldering of the plural heat radiating plates is ensured. Done in Thereby, the heat radiation of the high frequency power amplifier module is improved.

Further, by forming the heat radiating portion with a plurality of heat radiating plates and providing grooves in the heat radiating plate to be soldered to the printed circuit board, even if the amount of supplied solder is large in the assembly process,
Excess solder does not protrude onto the heat sink joined to the cap. This ensures that the plurality of heat sinks are soldered, thereby improving the heat dissipation of the high-frequency power amplifier module.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the embodiments of the present invention, first, the results of studies conducted by the inventors of the present invention up to the present invention will be described.

FIGS. 11 (a) and 11 (b) are schematic diagrams showing the cross-sectional shape (shape along line 9B-9B 'in FIG. 9 (b)) of the heat sink 101 obtained by cutting and pressing. Shown in Here, the constituent material of the heat sink 101 is copper, and the design value of the thickness t1 of the heat sink 101 is 1.0 m.
m. The thickness t2 of the groove 124 of the heat sink 101
Is 0.7 mm.

In the press working, as shown in FIG. 11B, sufficient working accuracy cannot be obtained, and particularly, the tip of the groove 124 tends to be thin. This tendency is remarkable when the design value of the thickness of the groove 124 is reduced. On the other hand, in cutting,
As shown in FIG. 11A, relatively sufficient processing accuracy is obtained.

Further, a high-frequency power amplifier module is manufactured using two types of heat sinks 101 having the shapes shown in FIGS. 11A and 11B, and their high-frequency operation characteristics are compared. FIG. 12 is a diagram showing a comparison of power gain due to a difference in the shape of the heat sink (that is, a difference in the processing method).

In a high-frequency power amplifier module using a heat sink formed by cutting, a stable power gain can be obtained regardless of the presence or absence of soldering between the metal cap and the heat sink, as shown by a black circle plot. Have been. However, in a high-frequency power module using a heat sink formed by pressing, as shown by a white circle plot, unless the metal cap and the heat sink are soldered (in the case of the dotted line), cutting is used. The power gain is higher than the obtained high frequency power amplifier module by 3 dB or more, and signs of oscillation appear. Although not shown in FIG. 12,
The variation in power gain between samples is also large.

Here, the power gain of the high-frequency power amplifier module obtained by press working by soldering the metal cap and the radiator plate to strengthen the joint therebetween is shown by the solid line in FIG. As shown by a white circle plot, the high-frequency power amplification module obtained by using the cutting process is as stable as the high-frequency power amplification module. From this, first, FIG.
In the configuration of the high-frequency power amplifier module of the related art described with reference to (a) and (b), it was confirmed that the processing accuracy of the heat sink 101 greatly affects the operation characteristics. It is clear that as the size and thickness of the high-frequency power amplification module progress, higher processing accuracy is required for the heat radiation plate 101. In the configuration of the high-frequency power amplification module of the related art, the heat radiation plate included therein is required. It is not preferable to mass-produce 101 by press working from the viewpoint of operating characteristics.

However, even in the configuration of the high-frequency power amplifier module of the prior art described with reference to FIGS. 10A and 10B, the thickness of the heat radiation plate 101 that enables the claw 108 to bend. , Sufficient heat dissipation cannot be obtained.

Hereinafter, several embodiments of the high-frequency power amplifier module of the present invention which overcomes the above-mentioned problems in the prior art will be described with reference to the accompanying drawings.

(First Embodiment) FIGS. 1A and 1B
3A and 3B are a cross-sectional view and an exploded perspective view illustrating a configuration of the high-frequency power amplifier module according to the first embodiment. Specifically, FIG.
(A) shows a cross-sectional structure taken along line 1A-1A 'shown in FIG. 1 (b).

One of the features of the configuration of this embodiment is that two types of heat radiating plates, a first radiating plate 1 and a second radiating plate 2, are used. Each of the heat sinks 1 and 2 is designed for each function. Specifically, in the first radiator plate 1, importance is attached to bonding to the metal cap 5, while in the second radiator plate 2, improvement in heat radiation of the entire high-frequency power amplifier module is emphasized.

In the illustrated high-frequency power amplifier module, the first radiator plate 1 and the second radiator plate 2 mounted thereon constitute a radiator. The printed circuit board 6 on which the circuit elements are mounted is soldered on the second heat sink 2. In particular, among the circuit elements used, the power FET 7 in the output stage having a large output power has a through hole 13 formed in the printed circuit board 6 in order to enhance its heat radiation.
And soldered directly onto the second heat sink 2.

The first radiating plate 1 is typically a thin flat plate having a thickness of about 0.3 mm, and has a claw portion 8 and a concave portion 9 provided therein. . The first heat sink 1 is joined to a metal cap 5 provided so as to cover a circuit element and the like mounted on the printed board 6. Specifically, the metal cap 5 and the first radiator plate 1 are joined by forming the convex portion 12 provided on the bent portion 11 of the metal cap 5 and the concave portion 9 provided on the claw portion 8 of the first heat radiator plate 1. It is done by interlocking. The bent portion 11 of the metal cap 5 is in contact with the projection 10 of the first heat sink 1. Also, the first heat sink 1
Is preferably a material having a spring property so that bonding with the metal cap 5 is maintained. For example,
Nickel white, stainless steel, titanium, a titanium alloy, or the like can be used, and typically nickel white is used.

In the above configuration, the claw portions 8 of the first heat sink 1
Since the contact area between the metal cap 5 and the bent portion 11 of the metal cap 5 can be made sufficiently large, the joining between the first heat sink 1 and the metal cap 5 can be made extremely good. For this reason, the high-frequency operation characteristics of the high-frequency power amplification module are stabilized, and variations can be suppressed.

Further, a second heat radiating plate 2 having a thickness of about 0.7 mm is placed on the first heat radiating plate 1 in order to enhance heat radiation. In this configuration, the thickness of the second heat radiating plate 2 can be arbitrarily increased to enhance heat radiation. Second
Is preferably a material having excellent thermal conductivity, for example, copper, aluminum, molybdenum, tungsten, or an alloy of these materials can be used. Is used. Alternatively, when weight reduction is required, it is effective to configure the second heat sink 2 with a material mainly made of aluminum. Here, since the second heat radiating plate 2 is used as a flat plate, high processing accuracy is not required.

The configuration of the present embodiment is also suitable for downsizing the high-frequency power amplifier module. This is shown in FIG.
This will be described with reference to FIG. Specifically, consider a high-frequency power amplifier module on which a printed circuit board having a length of about 10 mm and a width of about 15 mm is mounted.

FIGS. 2A and 2B are a cross-sectional view of the high-frequency power amplifier module of the present embodiment and a plan view of the first radiator plate 1 included therein. 2 (c) and 2 (d) show a cross-sectional view of a conventional high-frequency power amplifier module and a plan view of a heat sink 1 included therein. Further, FIG. 2E shows a comparison of the area of the high-frequency power amplification module covered with the metal cap 5 or 105.

As shown in FIGS. 2C and 2D, in a conventional high-frequency power amplifier module in which the heat radiating plate 101 is formed of a single metal plate, the thickness of the heat radiating plate 101 is improved in order to improve heat radiation. When the height is increased from about 0.3 mm to about 1.0 mm, the size of the entire high-frequency power amplification module increases by about 1.4 mm in both the vertical and horizontal directions. At this time, the occupied area of the high-frequency power amplification module including the metal cap 105 is changed from about 180 mm ² to about 220 mm ² , and is increased about 1.2 times.

On the other hand, in the configuration of this embodiment shown in FIGS. 2A and 2B, the first heatsink 1 has a thickness of about 0.1 mm.
If a 7 mm second heat radiating plate 2 is additionally used, a heat radiating effect equivalent to that of the related art can be obtained. At this time, since the size of the high-frequency power amplifier module is determined by the size of the first heat sink 1, the external area of the high-frequency power amplifier module does not increase.

Further, in the configuration of the present embodiment, assembly can be performed simply and accurately. Specifically, when mounting the second radiator plate 2 and the printed circuit board 6, both can be positioned by the claw portions 8 of the first radiator plate 1. For this reason,
The positioning of the second heat sink 2 and the printed circuit board 6 can be accurately performed without using an assembly jig for positioning. Further, by using the claw portion 8 of the first heat sink 1, the second heat sink 2 and the printed board 6 do not move even in a state where the solder is melted in the reflow furnace.

Further, in the configuration of the present embodiment, even if the number of heat radiation plates increases, the number of assembly steps does not become any complicated.
Specifically, in assembling the conventional high-frequency power amplification module, a plate solder is placed on the heat sink 101, a printed circuit board on which a matching circuit is formed, and a power FET are mounted thereon, and the reflow furnace is used. While they are fixed, the assembly of the high-frequency power amplifier module of the present embodiment only requires an additional step of sandwiching the plate solder between the first radiator plate 1 and the second radiator plate 2. By passing through the reflow furnace, the first radiator plate 1, the second radiator plate 2, the printed circuit board 6, and the power FET 7 can be simultaneously fixed. Therefore, in the present embodiment, there is no increase in cost due to an increase in the number of assembling steps, although the number of heat radiation plates 1 and 2 is increased.

Further, by applying solder plating to the first heat radiating plate 1 and the second heat radiating plate 2, the wettability of the solder is improved, and the fixing of the heat radiating plates 1 and 2 becomes stronger.

Further, in the configuration of the present embodiment, it is easy to mount the high-frequency power amplification module on a motherboard such as a communication device.

When mounting the high-frequency power amplification module on the motherboard, only the protrusion provided on the heatsink, not the entire surface of the heatsink, should be fixed to the ground of the motherboard by soldering in consideration of removal after mounting. There is. At this time, in the conventional configuration, since the heat radiation plate 101 is thick and has good heat conduction, reliable soldering cannot be realized unless the entire high-frequency power amplification module is heated. On the contrary,
In the present embodiment, since the protrusion 10 of the first heat sink 1 can be made thin, soldering can be performed by local heating. Also, soldering can be performed by local heating using a laser.

As described above, according to the present embodiment, the second
By arbitrarily increasing the thickness of the heat radiating plate 2, a high-frequency power amplifier module that is small and excellent in heat radiation can be realized. Further, even if a simple press working is used, the high-frequency bonding between the first heat sink 1 and the metal cap 5 can be improved, and the variation in the operating characteristics of the high-frequency power amplifier module can be suppressed. Further, the assembly process is the same as the conventional one, and the alignment accuracy of the printed circuit board 6 can be improved. Furthermore, mounting on a motherboard becomes easy, soldering by local heating is possible, and thermal stress applied to the high-frequency power amplifier module can be reduced.

For this reason, according to the present embodiment, it is possible to realize a high-frequency power amplifier module that is small, has excellent heat dissipation, is low in cost, has high mass productivity, and has stable high-frequency operation characteristics.

(Second Embodiment) FIG. 3A shows a metal cap 5 of a high-frequency power amplifier module according to a second embodiment.
FIG.

In the first embodiment, the projection 10 is provided only on the first radiator plate 1, but in the second embodiment,
The metal cap 5 is also provided with a protrusion 5a. In addition,
In the configuration of the present embodiment, the same reference numerals are given to the same components as those in the previous embodiment, and description thereof will be omitted here.

In mounting on the motherboard, the projection 10 of the first heat sink 1 and the projection 5a of the metal cap 5 are simultaneously soldered to the ground of the motherboard. By directly soldering the ground portion of the motherboard and the metal cap 5, heat conduction to the metal cap 5 is improved, heat dissipation is further improved, and high-frequency grounding is strengthened. This further improves the shield of the high-frequency power amplifier module, and extremely effectively acts to suppress abnormal oscillation due to unnecessary sneak of high-frequency signals and to reduce unnecessary radiation.

FIGS. 3 (b), (c), (d) and (e)
3 is various plan views of the high-frequency power amplifier module according to the present embodiment, and shows an example of the arrangement of the protrusions 10 and 5a according to the present embodiment. Although the potential of the metal cap 5 is reliably grounded in each of the arrangements shown,
In particular, as shown in FIG. 3C, if the protrusion 10 of the first heat sink 1 and the protrusion 5a of the metal cap 5 are arranged diagonally, the shield of the metal cap 5 can be reinforced most efficiently. .

In this embodiment, since the metal cap 5 is directly soldered to the ground together with the first heat radiating plate 1, not only the improvement of the heat radiation property but also the reliable grounding of the electric potential is realized. The earthquake resistance is also improved.

When the first heat sink 1 and the metal cap 5 are different in material and thickness when mounted on a motherboard, the timing at which solder begins to melt differs due to the difference in heat conduction, and high-frequency power amplification is performed. There was a problem that the module was mounted at an angle. However, by using a plurality of heat sinks, the material and thickness of the first heat sink 1 and the metal cap 5 can be made the same, and this problem can be solved.

As described above, according to the present embodiment, since the metal cap 5 is soldered directly to the ground together with the first heat sink 1, good heat conduction from the heat sink 1 to the metal cap 5 is achieved. And the heat dissipation is improved. Further, the shield of the metal cap 5 is strengthened, so that variations in operation characteristics and unnecessary radiation are suppressed. In addition, it is possible to reduce defective mounting on the motherboard and improve the earthquake resistance.

(Third Embodiment) FIGS. 4A and 4B
FIG. 4 is a cross-sectional view and an exploded perspective view illustrating a configuration of a high-frequency power amplifier module according to a third embodiment. Specifically, FIG.
(A) shows a cross-sectional structure taken along line 4A-4A 'shown in FIG. 4 (b).

One of the features of the configuration of the present embodiment is that a third radiator plate 3 is used in addition to the first radiator plate 1 and the second radiator plate 2. In the configuration of the present embodiment, the same reference numerals are given to the same components as those in the previous embodiment, and the description thereof will not be repeated.

The third heat radiating plate 3 is made of a material such as copper for improving the heat radiating property, similarly to the second heat radiating plate 2. Third
Is different from the second radiator plate 2 in that the thickness of the radiator plate 3 is smaller than that of the second radiator plate 2.
Is provided. The power FET 7 includes a printed circuit board 6 and a third heat sink 3 for improving heat dissipation.
Is soldered directly onto the second heat sink 2 through the through hole 13 provided in the second heat sink.

FIGS. 4C and 4D show the power FET 7.
FIG. In the conventional configuration, FIG.
As shown in FIG. 7, since the heat sink 2 under the printed circuit board 6 is flat, the solder melted during reflow is
Under the power FET 7 and the heat sink 2
May not be reliably performed. here,
If a concave portion (shallow concave portion) is provided on the surface of the heat sink 2 below the printed board 6 at a position corresponding to the region where the power FET 7 is mounted by soldering, a solder pool is formed in the concave portion. As a result, the power FET 7
, A large amount of molten solder is present around the periphery of the substrate, so that soldering can be performed more firmly. However, heat sink 2
In order to form a concave portion having a desired size and shape at a desired position, high processing accuracy is required, and the manufacturing cost of the heat sink 2 increases.

Therefore, in the present embodiment, as shown in FIG. 4D, the power FET 7 is mounted by soldering by combining the second heat sink 2 with the third heat sink 3 having the through hole 13. A recess is formed in the region to be formed. As a result, a solder pool is formed in the portion of the through hole 13 of the third heat radiating plate 3, and the soldering between the power FET 7 and the second heat radiating plate 2 becomes stronger, and the second heat radiating plate 2 is formed. Thermal conductivity to the substrate. In addition, assembly failure of the semiconductor package due to insufficient soldering can be reduced.

Further, similarly to the first embodiment, the heat radiating plates 1, 2, and 3, the printed circuit board 6, and the power FET 7 are simultaneously fixed in the same process by passing through a reflow furnace using a plate solder. be able to. Also, by applying solder plating to the third heat radiating plate 3 as well, the fixation of these is further strengthened.

As described above, according to this embodiment, the third heat sink 3 provided with the through hole 13 common to the printed circuit board 6 is provided.
Is formed below the power FET 7. Since the recess functions as a solder pool, soldering between the power FET 7 and the second radiator plate 2 becomes stronger, so that heat dissipation can be improved and defective assembly can be reduced.

(Fourth Embodiment) FIG. 5A is an external view of a printed circuit board 6 included in a high-frequency power amplifier module according to a fourth embodiment.

The characteristic configuration of this embodiment is shown in FIG.
The power FET (FIG. 5) is inserted into the through hole 20 formed in the printed circuit
(A) is provided with a projection 18 for positioning (not shown).

In order to improve the heat radiation of the high-frequency power amplifier module, it is very effective to provide a through hole 20 in the printed circuit board 6 and directly solder the power FET to the heat radiation plate. Here, the through hole is not limited to a hole whose periphery is completely surrounded by the printed circuit board 6 like the through hole 19 in FIG. Some of the printed circuit boards 6 have been removed and some of them are open.

FIG. 5B is an external view of the printed circuit board 6 for a high-frequency power amplifier module in which two types of through holes 19 and 20 of large and small sizes are arranged.

The four sides around the through hole 19 are surrounded by the printed circuit board 6. However, in the case of arranging two or more power FETs for high output or layout reasons, the size of the through hole becomes large, which limits the miniaturization of the high-frequency power amplifier module. More specifically, in the case of the layout as shown in FIG. 5B, the size of the through hole controls the size of the printed circuit board 6 in the vertical direction.

On the other hand, in order to reduce the size of the printed circuit board 6, it is only necessary to cut the upper part like a through hole 20 in FIG. However, it should be noted here that the size of the through hole must never be smaller than the size of the power FET. When considering the size in the vertical direction, if the through-hole 20 becomes smaller than the power FET, the power FET protrudes from the upper portion of the through-hole 20 and cannot be attached to the metal cap. Considering the manufacturing variation of the printed circuit board 6 and the package of the power FET, the size of the through-hole is as shown in FIG.
It is necessary to take a margin as shown by the dotted line in FIG.

However, when one side of the through hole is open, it is more difficult to position the power FET at the time of assembling than when the periphery of the through hole is surrounded by a printed circuit board. Further, during the reflow process, the power FET that has not been fixed may move and be shifted from a predetermined position. If the position of the power FET shifts, the line length changes by that amount, and the shift from the design increases, and the operating characteristics of the high-frequency power amplifier module deteriorate. Therefore, an assembling jig for positioning is required at the time of assembling. Therefore, in order to eliminate the need for such a positioning jig, a configuration in which the printed circuit board 6 is slightly left at a portion corresponding to the dotted line portion above the through hole 20 in FIG. .

However, here, the width of the printed circuit board 6 above the through hole 20 is restricted as follows.

The printed circuit board 6 for the high-frequency power amplifier module is generally manufactured in the form of a multi-piece collective board as shown in FIG. 5C, and is divided into individual pieces by the dividing lines 21 after mounting the chip parts. Is done. At this time, if the width of the printed board 6 above the through-hole 20 is narrow, the strength at that portion is insufficient, so that the printed board 6 above the through-hole 20 may be broken due to division. Considering the required strength of the printed circuit board 6 when divided into individual pieces, a printed circuit board 6 having a width of at least about 2 mm is required around the through hole 20. Therefore, the size of the printed circuit board 6 becomes unnecessarily large, and it is not possible to reduce the size of the high-frequency power amplification module.

Therefore, in the present embodiment, the position of the semiconductor package can be fixed by providing a configuration in which the projection 18 is provided above the through hole 20 as shown in FIG. At this time, the extra area at the top is about 0.2 m wide
m, and sufficient strength can be maintained even when divided into individual pieces. As a result, it is possible to realize a miniaturized high-frequency power amplifier module without breaking the printed circuit board 6 when dividing into individual pieces.

Further, since the projections 18 are formed, the positioning can be performed accurately without the need for an assembly jig for positioning when mounting the power FET.
As a result, it is possible to suppress variations in the operation characteristics of the high-frequency power amplification module.

In FIG. 5A, the projection 18 has a triangular shape, but the same effect can be obtained with any other shape such as a square or an arc.

As described above, according to the present embodiment, one side of the through hole 20 formed in the printed circuit board 6 is opened to improve heat dissipation, and the minute projections 18 are formed there. 6 can be reduced in size. In addition, the positioning of the power FET at the time of mounting can be performed accurately without requiring a special jig, and variation in the operating characteristics of the high-frequency power amplifier module can be suppressed.

(Fifth Embodiment) FIG. 6 is an exploded perspective view showing the configuration of a high-frequency power amplifier module according to a fifth embodiment. The basic configuration is the same as that of the first embodiment, but in this embodiment, a through hole 25 is provided in the second heat sink 2.

In order to improve heat dissipation, a plurality of heat sinks must be more firmly soldered. For that purpose, it is sufficient to increase the supply amount of solder in the assembly process,
This alone does not improve soldering. That is, it is important that the molten solder spreads evenly. For that purpose, it is effective to raise the processing temperature or lengthen the processing time when passing through a reflow furnace in the assembly process,
It is not preferable from the viewpoint of reliability. When the supply amount of the solder is increased, the excess solder is
When the metal cap 5 is attached, the cap 5 may float and the joining between the convex portion 12 and the concave portion 9 may not be engaged. In such a situation, the operation characteristics of the high-frequency power amplification module become unstable.

Therefore, in the present embodiment, the second heat sink 2 is provided with a through hole 25. The through-hole 25 is provided in the through-hole 13 for the power FET provided on the printed circuit board 6.
In contrast to this, it is provided for flowing solder. Since the solder spreads uniformly on both surfaces of the second heat radiating plate 2 through the through holes 25, there is no gap between the heat radiating plates 1 and 2 and the soldering becomes stronger. In addition, excess solder protrusion can be reduced.

It is preferable that the position of the through hole 25 is outside the FET mounting area. Because FET
In the mounting area, the direction in which the solder does not flow out from the mounting area and the pooling of the solder is conversely strengthens the fixing of the power FET,
In addition, heat dissipation can be improved.

As described above, according to the present embodiment, the second
By providing the through holes 25 in the heat radiating plate 2, the plurality of heat radiating plates are more firmly fixed, the heat radiation property is improved, and the solder can be prevented from protruding from the heat radiating plate. As a result, stable operation characteristics can be obtained in the high-frequency power amplifier module.

(Sixth Embodiment) FIG. 7A is an exploded perspective view showing a configuration of a high-frequency power amplifier module according to a sixth embodiment. Although the basic configuration is the same as that of the first embodiment, in this embodiment, the groove 2 is formed at the end of the second heat sink 2.
6 are provided.

As described in the fifth embodiment, in order to improve the heat radiation of the high-frequency power amplifier module, a plurality of heat radiating plates must be more firmly soldered. It is important that while the quantity of solder is supplied, the excess solder does not run off where it is not desired. Thus, in the present embodiment, the configuration is such that the groove 26 is provided at the end of the second heat sink 2. As a result, excess solder flows through the groove 26 and spreads uniformly on both surfaces of the second heat sink 2. In addition, it is possible to reduce the amount of the excessive solder protruding into the first heat sink 1.

FIG. 7B is an enlarged perspective view of a portion circled in FIG. 7A, and FIG. 7C is a cross-sectional view taken along line 7A-7A 'of FIG. 7B. FIG. The groove 26 is preferably formed along the projection 10 of the heat sink 1 as shown in these figures. If the groove 26 is formed in the portion of the projection 10, even if the solder overflows, the metal cap 5
The mounting yield is not affected, and the assembly yield can be further improved.

As described above, according to the present embodiment, the second
By providing the groove 26 in the heat radiating plate 2, the plurality of heat radiating plates are more firmly fixed and the heat radiation property is improved, and assembling failure due to the protrusion of the solder can be reduced.

(Seventh Embodiment) FIG. 8A is an exploded perspective view showing the configuration of a high-frequency power amplifier module according to a seventh embodiment. Although the basic configuration is the same as that of the first embodiment, in this embodiment, the side of the second heat sink 2 is chamfered.

The second heat radiating plate 2 preferably has as large an area as possible in order to improve heat radiation. Therefore, the second heat radiating plate 2 is designed with a value as close as possible to an allowable value determined by the inner size of the claw portion 8 of the first heat radiating plate 1. However, in the bending process of the claw portion 8, the root of the claw portion 8 does not become a right angle as shown in FIG. 8B, so that the design margin between the second heat sink 2 and the claw portion 8 is small. Therefore, a gap is formed between the first heat sink 1 and the second heat sink 2.

Thus, in the present embodiment, the second heat sink 2
In at least the surface on the side fixed to the first heat radiating plate 1, the sides are cut and chamfering is performed. This allows
As shown in FIG. 8C, the first and second heat radiating plates 1 and 2 are firmly fixed to each other without being affected by the bent shape of the claw portion 8. Thereby, a stable heat radiation effect can be obtained.

The same effect can be obtained regardless of whether the chamfered cut is flat or curved. Further, in the present invention, since the printed board 6 is fixed on the second heat sink 2, the design margin can be reduced without being affected by the bent shape of the claw portion 8. Therefore, variation in positioning by the claw portions 8 is reduced, and stable operation characteristics can be obtained.

As described above, according to the present embodiment, the second
By chamfering the sides of the heat sink 2, the first and second heat sinks 1 are not affected by the bent shape of the claw portion 8 even if a slight variation occurs in the processing of the package. And 2 can be brought into close contact with each other without a gap, and a high-frequency power amplifier module can be supplied stably.

[0103]

As described above, according to the present invention, it is possible to reduce the size of the power amplifying module and to improve the heat dissipation. This can suppress the heating of the power FET and improve the operation characteristics of the high-frequency power amplifier module.

Further, according to the present invention, the shield of the metal cap is strengthened, the variation in the operation characteristics can be reduced, the defective assembly can be reduced, and the mass productivity can be improved.

Further, according to the present invention, the earthquake resistance can be improved, and the mounting on the motherboard becomes easy, so that the reliability can be improved.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a high-frequency power amplifier module according to a first embodiment of the present invention, and FIG.
It is an exploded perspective view of the high frequency power amplification module of (a).

FIGS. 2 (a) to 2 (e) are a cross-sectional view and a plan view for comparing the size and shape of a radiator plate between the high-frequency power amplifier module of FIG.

FIG. 3A is a perspective view showing a part of a high-frequency power amplifier module according to a second embodiment of the present invention;
(B)-(e) is a top view in various variations of the high frequency power amplifier module of (a).

FIG. 4A is a cross-sectional view of a high-frequency power amplifier module according to a third embodiment of the present invention, and FIG.
It is an exploded perspective view of the high frequency power amplifier module of (a), and (c) and (d) are partial sectional views for explaining the composition near the power FET of the high frequency power amplifier module of (a).

FIGS. 5A to 5C are plan views illustrating the shape of a printed circuit board included in a high-frequency power amplifier module according to a fourth embodiment of the present invention.

FIG. 6 is an exploded perspective view of a high-frequency power amplifier module according to a fifth embodiment of the present invention.

FIG. 7A is an exploded perspective view of a high-frequency power amplifier module according to a sixth embodiment of the present invention, and FIGS. 7B and 7C are partial perspective views of the high-frequency power amplifier module of FIG. FIG.

FIG. 8A is an exploded perspective view of a high-frequency power amplifier module according to a seventh embodiment of the present invention, and FIGS. 8B and 8C illustrate the configuration of the high-frequency power amplifier module of FIG. FIG.

9A is a cross-sectional view of a high-frequency power amplifier module according to the related art, and FIG. 9B is an exploded perspective view of the high-frequency power amplifier module of FIG.

FIG. 10A is a cross-sectional view of another conventional high-frequency power amplifier module, and FIG. 10B is an exploded perspective view of the high-frequency power amplifier module of FIG.

11 (a) and (b) are cross-sectional views respectively showing shapes when a heat sink included in the high-frequency power amplifier module of FIG. 9 is formed by cutting and pressing.

FIG. 12 is a diagram showing a difference in power gain due to a difference in a method of processing a heat sink in the conventional high-frequency power amplifier module of FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st heat sink 2 2nd heat sink 3 3rd heat sink 5 Metal cap 5a Projection 6 Printed circuit board 7 Power FET 8 Claw 9 Depression 10 Projection 11 Bending part 12 Convex part 13 Through hole 18 Projection 19, 20 Through-hole 21 Dividing line 22 Solder 25 Through-hole 26 Groove 101 Heat sink 105 Metal cap 106 Printed circuit board 107 Power FET 108 Claw 109 Depression 110 Projection 111 Bend 112 Projection 113 Through-hole 123 Hook 124 Groove

Claims (13)

(57) [Claims] 1. A heat radiator, a printed circuit board fixed to the heat radiator, a power amplifying semiconductor element mounted on the printed circuit board, and a cap, wherein the heat radiator comprises a plurality of heat radiating plates. The plurality of radiators include at least a lowermost first radiator plate and a second radiator plate fixed on the first radiator plate. High-frequency power amplification module bonded to the cap. 2. The high-frequency power amplifier module according to claim 1, wherein the second heat sink is thicker than the first heat sink. 3. The high frequency power according to claim 1, wherein the first radiator plate is made of a material having a spring property, and the second radiator plate is made of a material having a high thermal conductivity. Amplification module. 4. The high-frequency power amplifier module according to claim 1, wherein a concave portion is formed on a surface of the second heat sink at a position corresponding to a mounting position of the power amplifying semiconductor element. 5. The high frequency power amplifier module according to claim 1, wherein a through hole is provided in said second heat sink. 6. The high-frequency power amplifier module according to claim 1, wherein a groove is formed at an end of said second heat sink. 7. At least the first of the second heat sinks
The high-frequency power amplification module according to claim 1, wherein a side portion is chamfered on a surface fixed to the heat sink. 8. A radiator including a plurality of radiators, a printed circuit board fixed to the radiator, and a power amplifying semiconductor element mounted on the printed circuit board. A high-frequency power amplifier module, wherein a common through hole is provided in a heat radiation plate fixed to the printed circuit board among the heat radiation plates. 9. A radiator, a printed circuit board fixed to the radiator, a power amplifying semiconductor element mounted on the printed circuit board, and a cap, wherein the radiator and the cap have protrusions. Are formed, and the bottom surfaces of the protrusions are located at the same height as each other. 10. The high-frequency power amplification module according to claim 9, wherein the heat radiating section includes a plurality of heat radiating plates. 11. A heat radiator, a printed circuit board fixed to the heat radiator, a power amplifying semiconductor element mounted on the printed circuit board,
A high-frequency power amplifier module, comprising: a through hole provided in the printed circuit board; and a projection used for positioning when mounting the power amplifying semiconductor element, provided toward the through hole. 12. The high frequency power amplifier module according to claim 11, wherein said heat radiating section includes a plurality of heat radiating plates. 13. A radiator plate, a printed circuit board fixed to the radiator plate, a power amplifying semiconductor element mounted on the printed circuit board,
A high-frequency power amplifier module, comprising: a concave portion formed at a position corresponding to a mounting position of the power amplifying semiconductor element on a surface of the heat sink.