JP2751915B2 - Manufacturing method of high frequency power module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field effect transistor, particularly a field effect transistor having a Schottky junction formed on a semi-insulating GaAs substrate.
It is described as SFET. The present invention also relates to a high-frequency power module including a high-frequency multi-stage power amplifier circuit using a power amplification semiconductor such as a Si bipolar transistor and a chip component, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A power module is used for a transmitter of a mobile communication device such as a transceiver or a mobile phone, and its performance such as shape and efficiency determines the size of the communication device and the length of talk time. Parts. A power module is a high-frequency multi-stage power amplifier circuit in which a plurality of power amplification semiconductors and chip components such as resistors and capacitors are mounted on a printed circuit board on which a microstrip line is formed. For this purpose, it is generally soldered on a metal heat sink and is generally covered with a metal cap.

The heat radiation effect of the power module is an important factor in more stably extracting the characteristics of the high-frequency multi-stage power amplifier circuit. If the heat radiation is insufficient, the power amplification semiconductor is heated and the current becomes difficult to flow, so that the output power is reduced. It is advantageous that the power module be as small as possible because the equipment used is as small as a mobile communication device. However, the smaller the size, the lower the heat radiation efficiency, and it is necessary to improve the heat radiation efficiency.

A semiconductor requiring heat radiation is directly fixed on a metal heat radiation plate through a hole formed in a printed circuit board with solder or the like. If the solder between the power amplification semiconductor and the radiator plate is poor, heat is less likely to be transmitted from the semiconductor to the radiator plate, causing the semiconductor to heat.

FIG. 6A is a configuration diagram of a conventional two-stage power module using two MESFETs. The printed circuit board 6 has a first gate terminal Vg1, a first drain terminal Vd1, a second gate terminal Vg2, a second drain terminal Vd2, a high frequency power input terminal Pin, and a high frequency power output terminal Pout for supplying a DC bias. Are connected to an external circuit. The high-frequency power input from the input terminal Pin is amplified by the first-stage semiconductor 9, further amplified by the second-stage semiconductor 7, and output from the output terminal Pout.

FIG. 6B is a cross-sectional view taken along the line AA 'in FIG. 6A. The first-stage semiconductor 9 is mounted on the printed circuit board 6 because the output power does not require heat radiation as much as it is small. However, the second-stage semiconductor 7 has a large output power and requires heat radiation, so Directly fixed. As shown in the figure, the printed circuit board 6 is covered with a metal cap 8 to prevent unnecessary radiation. FIGS. 6A and 6B
The printed circuit board 6 on which the chip components and the first-stage semiconductor 9 are mounted is fixed to the heat sink 12. The second-stage semiconductor 7 requiring heat radiation is directly fixed to the heat radiation plate 12 through a hole formed in the printed circuit board by soldering or the like. Plate solder is often used as the solder material. The conventional heat radiating plate 12 often uses nickel or the like as a plating material, and the solder coating is poor. Also, the printed circuit board 6 and the second-stage semiconductor 7 have different heat capacities, and the plate solder immediately below the printed circuit board 6 melts first,
Since there is a phenomenon that the plate solder immediately below the second-stage semiconductor 7 is sucked between the printed board 6 and the heat radiating plate 12, the nickel-plated heat radiating plate 12 is further deteriorated in solder coating.

FIGS. 7 (a) and 7 (b) show a three-dimensional configuration of a conventional metal cap 8 and a radiator plate 12. FIG. To join the metal cap 8 and the heat sink 12, the projection 15 of the metal cap 8 is used.
And the concave portion 16 of the heat radiating plate 12 are engaged with each other and pinned. However, these are only point contacts, and the heat conduction from the heat radiating plate 12 to the metal cap 8 is poor, and the heat radiating effect of the metal cap 8 is reduced. Is not obtained enough,
The heat radiating plate 12 and the metal cap 8 may make a rattling sound due to the vibration, and this has been a cause of giving noise to the receiving unit in a mobile phone or the like.

Further, the conventionally used metal cap 8 is formed of a flat plate, cannot have a large surface area, and is not sufficient to enhance the heat radiation effect.

The heat radiation plate 12 has a thickness of 0.2 mm to 0.3 mm.
mm, but the second stage semiconductor 7
The thickness of the heat radiating plate immediately below was also thin, and the heat radiating effect was insufficient.

[0010]

In the conventional metal case for a power module shown in FIGS. 6 and 7, when the printed circuit board and the semiconductor are fixed to the heat radiating plate by using solder or the like, the semiconductor and the heat radiating plate are connected to each other. Since the state of fixation is poor and the heat conduction from the semiconductor to the heat radiating plate is poor, the semiconductor is liable to be heated and a problem that a predetermined power cannot be obtained has occurred. Further, the heat radiating plate used is formed by processing a thin metal flat plate, and the metal thickness immediately below the semiconductor requiring heat radiation is also thin, and the heat radiating effect is not sufficient.

In the conventional metal case for a power module shown in FIG. 1, the heat sink and the metal cap are only pinned, and are merely held in point contact. Was poor in heat conduction, and the metal cap could not contribute to heat release. Furthermore, if vibration is applied due to insufficient bonding, the heat sink and the metal cap may make a rattling sound, which causes noise when applied to a mobile phone with a receiving unit nearby. Had become. Furthermore, since the metal cap is made of flat metal, the surface area of the metal cap cannot be increased, and thus the metal cap is not suitable as a heat dissipation structure.

The present invention has been made in view of the above, and an object of the present invention is to provide a method of manufacturing a high-frequency power module having an excellent heat radiation effect and having earthquake resistance in a high- frequency multistage power amplifier circuit.

[0013]

In order to solve the above-mentioned problems, the present invention provides a power module of a high-frequency multi-stage power amplifier circuit, in which a printed circuit board and a heat radiating plate for fixing a semiconductor which needs heat radiation by soldering are plated with solder. Configuration.

According to another aspect of the present invention, there is provided a power module for a high-frequency multi-stage power amplifier circuit, wherein a heat radiating plate for fixing a printed board and a semiconductor requiring heat radiation by soldering is provided immediately below the semiconductor requiring heat radiation. The thickness of the heat sink is thicker than that of the other heat sinks.

Further, in order to solve the above-mentioned problems, the present invention provides a power module of a high-frequency multi-stage power amplifier circuit in which a metal cap covering a printed circuit board and a surface of a heat sink are plated with solder.

[0016]

As described above, according to the present invention, as a power module of a high-frequency multi-stage power amplifier circuit, a surface of a heat radiating plate for fixing a printed circuit board and a semiconductor requiring heat radiation by soldering is plated with solder. The wettability of the solder is improved, the heat transfer efficiency from the semiconductor to the heat sink is improved, and the heating of the semiconductor is suppressed.

As described above, according to the present invention, as a power module of a high-frequency multi-stage power amplifier circuit, a heat radiating plate for fixing a printed board and a semiconductor requiring heat dissipation by soldering is provided by a heat radiating portion immediately below the semiconductor requiring heat dissipation. By adopting a configuration in which the thickness of the plate is thicker than that of the other portions of the heatsink, the heat dissipation efficiency of the heatsink is improved, which is effective in suppressing semiconductor heating.

Further, as described above, the present invention provides a power module of a high-frequency multi-stage power amplifier circuit in which a metal cap for covering a printed circuit board and a surface of a radiator plate are plated with solder, so that the metal cap is printed. The heat radiating plate and the metal cap can be joined by soldering simply by covering the heat radiating plate on which the substrate and the semiconductor are fixed and heating by reflow or the like. Thereby, the efficiency of heat conduction from the heat radiating plate to the metal cap is improved, and the heat radiating effect of the metal cap is obtained. Furthermore, since the heat sink and the metal cap are joined by solder, the seismic resistance increases compared to conventional pinning, so that the heat sink and the metal cap do not make vibration noise due to the vibration of the metal case. When used in a mobile phone or the like having a near, the adverse effect of noise is eliminated.

[0020]

[0021]

FIG. 1 shows the structure of a radiator plate of a metal case for a power module of a high-frequency multi-stage power amplifier circuit according to a first embodiment. Hereinafter, parts equivalent to those in FIGS. 6 and 7 which have already been described in the description of the present invention are denoted by the same reference numerals.

In the first embodiment shown in FIG.
(A) is a plan view of a heat sink whose surface is plated with solder. FIG. 1B is a cross-sectional view taken along line AA ′ of FIG. The radiator plate 1 includes a metal part 2, a plating part 3,
It is composed of three layers of the solder plating part 4. FIG. 1C shows a cross-sectional view of the power module. The printed circuit board 6 on which the solder chip components and the power semiconductor are mounted is fixed to the radiator plate 1 whose surface is plated with solder by soldering or the like.
The second-stage semiconductor 7 requiring heat radiation is directly fixed to the heat-radiating plate 1 whose surface is plated with solder through a hole formed in the printed circuit board 6 with solder or the like. Compared with the conventional nickel-plated heatsink, the heat-dissipation plate 1 whose surface is solder-plated has better solderability, so that the state of fixation of the second-stage semiconductor 7 is greatly improved, and the heat transfer efficiency is improved. Heating of the semiconductor 7 was suppressed, and a decrease in output power was avoided. The same effect was obtained only by adopting a configuration in which the heat radiating plate 1 had the plated portion 4 as a surface.

FIG. 2 shows a configuration of a metal case for a power module of a high-frequency multi-stage power amplifier circuit according to a second embodiment. FIG. 2A shows a plan view of the module. FIG. 2 (b)
FIG. 3 shows a cross-sectional view taken along line AA ′ of FIG. FIG.
As shown in (b), a heat radiating plate 5 was used in which the thickness of the heat radiating plate immediately below the semiconductor requiring heat radiation was thicker than the others. As a result, the heat radiation efficiency of the heat radiating plate 5 is improved, and the suppression of the heating of the second-stage semiconductor 7, which requires heat radiation, has been found effective in avoiding a decrease in output power.

FIG. 3 shows the structure of the metal cap of the metal case for the power module of the high-frequency multi-stage power amplifier circuit of the third embodiment. FIG. 3A is a plan view of the metal cap 10 whose surface is plated with solder. FIG.
FIG. 3A is a cross-sectional view taken along line AA ′. The metal cap 10 whose surface is plated with solder is composed of three layers: a metal part 2, a plating part 3, and a solder plating part 4.

FIG. 4 shows the configuration of a metal case for a power module according to the third embodiment. FIG. 4A is a front view of a metal case for a power module of a high-frequency multi-stage power amplifier circuit.
FIG. 4B is a cross-sectional view taken along line AA ′ of FIG. Metal cap 1 whose surface is plated with solder
In the final step of the assembly after covering the heat sink 1 with the solder plating on the surface, the solder plating is melted just by heating through reflow or the like, and the gap between the two is joined by the solder 11. Since the heat radiating plate 1 and the metal cap 10 are joined by soldering, the heat conduction efficiency of the two is improved as compared with the conventional pinning only, and the heat radiating effect of the metal cap 10 is enhanced. Further, since the heat radiating plate 1 and the metal cap 10 are joined by soldering, the quake resistance is increased as compared with the conventional pin-fixed type, and the heat radiating plate 1 and the metal cap 10 make a vibration sound due to the vibration of the metal case. When used in a mobile phone having a receiving unit nearby, the adverse effect of noise could be eliminated. Note that the metal cap 10 and the heat radiating plate 1 had the same effect only by adopting a configuration in which the plated portion 4 was the surface.

FIG. 5 shows the configuration of a metal case for a power module of a high-frequency multistage power amplifier circuit according to a fourth embodiment. FIG. 4A is a front view of a metal case for a power module. FIG. 4B is a cross-sectional view taken along line AA ′ of FIG. By using the metal cap 13 with the radiating fins, the heat from the heat radiating plate 1 can be efficiently released to the atmosphere as compared with the metal cap made of a conventional flat metal, and the output of 1 W can be achieved with a small power module of 18 mm × 13 mm or less. Despite the above, a decrease in output power was prevented.

[0027]

As described above, the present invention has the following effects.

1) As a power module of a high-frequency multi-stage power amplifier circuit, the surface of a printed board and a heat radiating plate for fixing a semiconductor which needs heat radiation by soldering is plated with solder, so that solderability is improved. However, the efficiency of heat conduction from the semiconductor to the heat sink was improved, and the heating of the semiconductor was suppressed.

2) As the power module of the high-frequency multi-stage power amplifier circuit, the heat radiating plate for fixing the printed board and the semiconductor which needs heat radiation by soldering has the thickness of the heat radiating plate immediately below the semiconductor requiring heat radiation. It has been found that by making the structure thicker than the others, the heat radiation efficiency of the radiator plate is improved, which is effective in suppressing the heating of the semiconductor.

3) As the power module of the high-frequency multi-stage power amplifier circuit, the metal cap for covering the printed circuit board and the surface of the heat sink are solder-plated.
In the final step of assembly, the heat sink and the metal cap can be joined by soldering simply by placing the metal cap on the heat sink to which the printed circuit board and the semiconductor are fixed and heating through reflow or the like. As a result, the heat conduction efficiency of the two is improved as compared with the conventional pinning only, and the heat dissipation effect of the metal cap is enhanced. Furthermore, compared to the conventional pin-only type, the shock resistance is increased, and the heat radiation plate and the metal cap do not make vibration noise due to the vibration of the metal case, so it is used for mobile phones etc. with a receiving unit nearby When this was done, the adverse effects of noise could be eliminated.

4) As a power module of a high-frequency multi-stage power amplifier circuit, a heat dissipation fin is provided on a metal cap covering a printed circuit board, so that the heat dissipation efficiency of the power module can be increased and the semiconductor module can be effectively prevented from being heated. I found that there was.

[Brief description of the drawings]

1A is a plan view of a radiator plate of a metal case for a power module of the present invention. FIG. 1B is a cross-sectional view of a radiator plate of a metal case of a power module of the present invention. Cross section of heat sink

2A is a plan view of a metal case for a power module of the present invention. FIG. 2B is a cross-sectional view of a metal case for a power module of the present invention.

3A is a plan view of a metal cap of the power module metal case of the present invention. FIG. 3B is a cross-sectional view of the metal cap of the power module metal case of the present invention.

4A is a plan view of a metal case for a power module of the present invention. FIG. 4B is a cross-sectional view of a metal case for a power module of the present invention.

5A is a plan view of a metal case for a power module of the present invention. FIG. 5B is a cross-sectional view of a metal case for a power module of the present invention.

6A is a plan view of a conventional metal case for a power module. FIG. 6B is a cross-sectional view of a conventional metal case for a power module.

7A is a perspective view of a metal cap of a conventional metal case for a power module. FIG. 7B is a perspective view of a radiator plate of a metal case of a conventional power module.

[Description of Reference Numerals] 1 Heat sink having a surface plated with solder 2 Metal part 3 Plated part 4 Solder plated part 5 Thick heat sink just below semiconductor 6 Printed circuit board 7 Second stage semiconductor 8 Metal cap 9 First stage semiconductor 10 Metal cap having a surface plated with solder 11 Solder 12 Heat sink 13 Metal cap with heat radiation fins 15 Convex part 16 Concave part

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsunori Nishi 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Chinatsu Higashi 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-4-302196 (JP, A) (58) Fields investigated (Int. ⁶ , DB name) H05K 7/20

Claims (8)

(57) [Claims] 1. A step of fixing a printed board and a power amplification semiconductor on a heat sink using solder or the like, and a step of covering the printed board with a metal cap, wherein the step is connected to the metal cap of the heat sink. A method for manufacturing a high-frequency power module, comprising: 2. A method for fixing a printed circuit board and a power amplification semiconductor on a heat sink using solder or the like, and a step of covering the printed circuit board with a metal cap. A method of manufacturing a high-frequency power module, wherein a thickness of a plate is thicker than other radiator plates, and a portion of the radiator plate to which the semiconductor is fixed is plated with solder. 3. A step of fixing a printed board and a power amplification semiconductor on a heat sink using solder or the like, a step of covering the printed board with a metal cap, and a portion of the heat sink connected to the metal cap. Is solder plated,
Bonding the metal cap and the heat sink by melting the solder plating. 4. 請, characterized in that be solder-plated portion connected to the heat radiating plate of the metal cap
The method for manufacturing a high-frequency power module according to claim 3 . 5. A radiator plate, wherein the radiator plate is formed by using solder or the like.
The printed circuit board and the semiconductor for power amplification,
A metal cap covering the printed circuit board;
The part of the plate connected to the metal cap is plated with solder.
A mobile phone comprising: a high-frequency power module according to claim 1; and a receiving unit disposed near the module. 6. A radiator plate, wherein the radiator plate is formed by using solder or the like.
The fixed printed circuit board and the semiconductor for power amplification;
A metal cap covering the lint substrate,
The surfaces of the cap and the heat sink are plated with solder,
The metal cap and the radiator plate melt solder plating.
A mobile phone comprising: a high-frequency power module that is more bonded; and a receiving unit that is disposed near the module. 7. A heat radiating plate, wherein the heat radiating plate is formed by using solder or the like.
The printed circuit board and the semiconductor for power amplification,
A metal cap covering the printed circuit board;
The part of the plate connected to the metal cap is plated with solder.
A communication device having a high-frequency power module as described above , wherein the high-frequency power module is used as a transmission unit. 8. A radiator plate, wherein the radiator plate is formed by using solder or the like.
The fixed printed circuit board and the semiconductor for power amplification;
A metal cap covering the lint substrate,
The surfaces of the cap and the heat sink are plated with solder,
The metal cap and the radiator plate melt solder plating.
A communication device having a high-frequency power module adhered thereto, wherein the high-frequency power module is used as a transmission unit.