JP3941634B2 - High frequency module and communication device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency module in which a metal case for high-frequency shielding is mounted on a substrate on which electronic components are mounted, and more particularly to a high-frequency module used in a communication device that is mounted with high density, such as a mobile phone.
[0002]
[Prior art]
Conventionally, as this type of high-frequency module, there are those shown in Japanese Patent Application Laid-Open Nos. 4-328903 and 9-307261. FIG. 4 is a perspective view of a conventional high-frequency module disclosed in Japanese Patent Laid-Open No. 4-328903, and FIG. 5 is an exploded perspective view thereof. In the figure, reference numeral 1 denotes a high-frequency module, which includes a substrate 2 on which an electronic component 4 is mounted, and a metal case 3 for high-frequency shielding that is fixed to the substrate 2 so as to cover the substrate 2 and the electronic component 4. The metal case 3 has a bottom opening type and is provided with protrusions 3a and 3b on side surfaces. On the other hand, the substrate 2 has recesses 2a and 2b corresponding to the protrusions 3a and 3b of the metal case on the side surface, and metallization processing for joining the metal case to the recesses 2a and 2b and the end surfaces 2c and 2d is performed. It has been subjected. Thus, the metal case 3 is formed by fitting the protrusions 3a and 3b to the recesses 2a and 2b of the substrate and soldering them, and soldering the end surfaces 3c and 3d to the end surfaces 2c and 2d of the substrate. The high frequency module 1 is formed.
[0003]
FIG. 6 is an exploded perspective view of a conventional high-frequency module disclosed in Japanese Patent Laid-Open No. 9-307261. In this high-frequency module, the end face of the metal case is not fixed to the end face of the board, but the ground electrodes 2e and 2f are provided at locations adjacent to the end face of the board on the electronic component mounting surface. 3f is soldered. Thereby, the metallization processing of the substrate for fixing the metal case can be performed collectively before the division of the original substrate for mass production of a large number of substrates, so that the manufacturing cost is reduced.
[0004]
[Problems to be solved by the invention]
As described above, the conventional high-frequency module is thin because the end surface of the metal case is solder-bonded to the end surface of the substrate, or the concave portion is provided on the side surface of the substrate, and the protrusion of the metal case is fitted and fixed thereto. In the substrate, it is difficult to fix the side surface and the end surface, and a process such as a metallization process or a recess is required on the side surface or the end surface of the substrate, which increases the manufacturing cost.
[0005]
Therefore, the main object of the present invention can be applied to a thin substrate where it is difficult to fix the metal case on the side surface or the end surface, and the metal case can be joined without performing metallization on the side surface or end surface of the substrate or providing a recess. An object of the present invention is to provide a high-frequency module that is easy to manufacture and capable of high-density mounting, and a communication device using the same.
[0006]
[Means for Solving the Problems]
The high-frequency module of the present invention is provided with solder terminals in a part including the four corners of the metal case, and a land corresponding to the solder terminal of the metal case is provided on the electronic component mounting surface of the substrate, and the metal case is soldered to the substrate. It is a thing.
Since the land is provided on the electronic component mounting surface of the substrate and the metal case is soldered, the metal case can be mounted even on a thin substrate. In addition, since it is not necessary to perform metallization on the side surfaces and end surfaces of the substrate and the metal case can be mounted at the original substrate stage, the production efficiency can be improved and the manufacturing cost can be reduced.
In addition, since the metal case is partially fixed by providing soldering terminals on a part rather than the entire circumference, the stress generated on the substrate is relieved by the warp of the case or the substrate. Also, when the vertical and horizontal lengths of the metal case are not uniform, self-alignment on the long side works strongly with full-surface soldering, so it returns to an appropriate position for misalignment in the short side, but the long side direction Although it is considered that the position does not return to an appropriate position with respect to the deviation, it is expected that uniform self-alignment works in both the long side direction and the short side direction by partially soldering.
[0007]
Further, the high frequency module of the present invention is preferably one in which a solder terminal of a metal case is bent.
Thereby, since it becomes surface bonding, the adhering force is improved, and the position accuracy of the metal case is improved by the self-alignment effect, so that a more reliable product can be obtained.
[0008]
The high-frequency module according to the present invention also includes solder terminals at the middle of the four corners of the metal case, a land corresponding to the solder terminal is provided on the electronic component mounting surface of the substrate, and the solder terminal is provided on the land. More preferably, these are solder bonded.
Thereby, the bonding strength is further improved and the high frequency shielding effect is also improved.
[0009]
The high-frequency module of the present invention is more preferably one in which at least one bending direction is changed among the solder terminals of the metal case.
Thereby, compared with the case where the bending is aligned in one direction, the metal case is less likely to be dragged against the load from above the high-frequency module, and the load resistance strength of the metal case is improved.
[0010]
The high-frequency module of the present invention is more preferably one in which the thermal expansion coefficient of the metal case is smaller than the thermal expansion coefficient of the substrate.
As a result, the center of the board warps to the metal case side (convex upward) when returned to normal temperature after assembly at high temperature, so the center of the board warps to the opposite side (downward convex) of the metal case As compared with the above, stress applied to the terminal portion of the substrate is relieved, and microcracks generated in the terminal portion and the like are prevented, and a more reliable product can be obtained. In addition, in a substrate having electrodes on the peripheral portion of the back surface of the substrate, the center portion of the substrate does not warp so as to protrude downward with respect to the peripheral portion of the substrate, so that the contact property of the electrodes is ensured.
[0011]
Further, the high-frequency module of the present invention more preferably has a difference in thermal expansion coefficient between the metal case and the substrate of 5 ppm or less.
As a result, the flatness of the substrate is improved, and a high-frequency module suitable for high-density mounting requirements such as a mobile phone can be obtained.
[0012]
The communication device of the present invention is obtained by forming at least a high-frequency circuit portion on the high-frequency module of the present invention.
[0013]
The above object, other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the embodiments of the present invention with reference to the drawings.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view of a high-frequency module according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof. In the figure, reference numeral 10 denotes a high-frequency module, which includes a substrate 12 on which an electronic component 16 is mounted, and a metal case 14 for high-frequency shielding that is fixed to the substrate 12 so as to cover the substrate 12 and the electronic component 16. Solder terminals 14 a, 14 b, 14 c and 14 d are provided at the four corners of the metal case 14. In addition, solder lands 12a, 12b, 12c, and 12d are provided at the four corners of the electronic component mounting surface of the substrate 12 corresponding to the soldering terminals 14a, 14b, 14c, and 14d. The metal case 14 is mounted on the substrate 12 by soldering the solder terminals 14 a to 14 d of the metal case 14 to the solder lands 12 a to 12 d of the substrate 12.
[0015]
In this way, the metal case can be mounted even on a thin substrate by providing the solder land on the component mounting surface of the substrate and fixing the metal case. In addition, since it is not necessary to perform metallization on the side surfaces and end surfaces of the substrate and the metal case can be mounted at the original substrate stage, the production efficiency can be improved and the manufacturing cost can be reduced.
[0016]
In the present embodiment, the solder terminals 14a to 14d of the metal case 14 are bent and surface-bonded to the corresponding solder lands 12a to 12d of the substrate 12. As described above, the surface bonding increases the fixing force and improves the position accuracy of the metal case by the effect of self-alignment, so that a more reliable product can be obtained.
[0017]
In the present embodiment, in addition to the soldering terminals 14a to 14d at the four corners of the metal case, the soldering terminals 14e and 14f that are bent in the middle are provided and soldered to the solder lands 12e and 12f of the corresponding substrate. ing. Thereby, the bonding strength is further improved and the high frequency shielding effect is also improved.
[0018]
In the present embodiment, the bending directions of the solder terminals 14a to 14f of the metal case 14 are different by 90 degrees between the four corner solder terminals 14a to 14d and the intermediate solder terminals 14e and 14f. Thereby, compared with the case where the bending is aligned in one direction, the metal case is less likely to be dragged against the load from above the high-frequency module, and the load resistance strength of the metal case is improved.
[0019]
In the present embodiment, a material having a difference in thermal expansion coefficient between the substrate 12 and the metal case 14 of 5 ppm or less is used. Specifically, the material of the substrate 12 is a ceramic substrate that is a dielectric material mainly composed of a mixture of barium oxide and silica oxide, and has a thermal expansion coefficient of 11.6 ppm. On the other hand, the material of the metal case 14 is NiFe50 alloy, and the thermal expansion coefficient is 10.5 ppm.
[0020]
In this way, by using a material having a small difference in thermal expansion coefficient, the stress concentration of the soldered portion of the metal case 14 is reduced, and the flatness of the substrate 12 when the assembly is returned to room temperature after assembly at high temperature is increased. Can be maintained, and a more reliable product can be obtained. In particular, by setting the difference in thermal expansion coefficient between the two to 5 ppm or less, the flatness when a substrate having a length of 20 mm is returned to room temperature after assembling using a high-temperature solder (melting point: 220 ° C. or higher and 250 ° C. or lower), The height of the solder surface can be 0.1 mm or less. As a result, a high-frequency module suitable for high-density mounting requirements such as a mobile phone can be obtained.
[0021]
Moreover, in this Embodiment, the thermal expansion coefficient of a metal case is made smaller than the thermal expansion coefficient of a board | substrate. This is because the thermal expansion coefficient of the metal case is made smaller than the thermal expansion coefficient of the board, so that the center part of the board warps to the metal case side when returned to room temperature after assembly at high temperature. Concentration is relaxed, and microcracks generated in the terminal portion and the like are prevented, and a more reliable product can be obtained. Furthermore, when the electrode on the back surface of the substrate is in the peripheral portion of the substrate, the contact property of the electrode is ensured.
[0022]
Here, the result of having measured the difference of the maximum principal stress concerning the soldering terminal part of a board | substrate when changing the thermal expansion coefficient of a metal case is shown below. The substrate to be joined is a ceramic substrate having a size of 14 mm × 9.7 mm, a thickness of 0.6 mm, and a material mainly composed of a mixture of barium oxide and silica oxide as described above, and has a thermal expansion. The coefficient is 11.6 ppm.
1. Metal case 1
(Material: phosphor bronze, thermal expansion coefficient: 17.8 ppm)
Maximum principal stress: 120 N / m ²
2. Metal case 2
(Material: NiFe50 alloy, coefficient of thermal expansion: 10.5 ppm)
Maximum principal stress: 10 N / m ²
[0023]
In this way, it can be seen that by reducing the difference in thermal expansion coefficient between the board and the metal case, naturally the stress concentration on the soldering terminals of the board can be greatly relieved, but it is considered from the difference in the absolute value of the thermal expansion coefficient. Thus, it is considered that the stress concentration applied to the soldering terminal portion of the substrate can be further alleviated by reducing the thermal expansion coefficient of the metal case relative to the thermal expansion coefficient of the substrate. Thereby, the microcrack which generate | occur | produces in a terminal part etc. is prevented, and a more reliable product is obtained.
[0024]
In the above embodiment, the difference between the thermal expansion coefficient of the substrate and the metal case is 5 ppm or less, but the present invention is not limited to this, and the object of the present invention is not limited to this. Is achieved.
[0025]
In the above embodiment, among the solder terminals of the metal case, the bending direction of the solder terminal at the middle part is different by 90 degrees. However, the present invention is not limited to this. Some bending directions may be changed. Further, the change in direction is not necessarily 90 degrees, and it may be bent in an arbitrary direction.
[0026]
Further, in the above embodiment, the bending direction of the solder terminal of the metal case is made to be different by 90 degrees. However, the present invention is not limited to this, and it is not necessary to provide a soldering terminal having a different bending direction of 90 degrees. The object of the present invention is achieved.
[0027]
In the above embodiment, the solder terminals are provided at two locations near the center of the side surface of the metal case. However, the present invention is not limited to this, and an appropriate length is provided at an appropriate portion on each side as necessary. Therefore, an appropriate number may be provided. Thereby, it is possible to obtain a necessary high frequency shielding effect while avoiding a conflict with components mounted on the substrate.
[0028]
In the above embodiment, solder terminals are provided in the middle of the four corners of the metal case, and lands corresponding to the component mounting surface of the board are provided and soldered. However, the present invention is not limited to this. Instead, the object of the present invention can be achieved without fixing the intermediate portion.
[0029]
In the above embodiment, the solder terminal of the metal case is bent outward, but may be bent inward. In this way, the board space can be utilized more effectively.
[0030]
Moreover, in the said embodiment, although the soldering terminal of a metal case is bent, it is not limited to this, The objective of this invention is achieved even if it does not bend a soldering terminal.
[0031]
In the above embodiment, the solder terminals are provided at both ends of the side surface of the metal case, but it goes without saying that the same effect can be obtained even if they are provided in the four corners in an L shape.
[0032]
FIG. 3 is a block diagram of a communication apparatus according to an embodiment of the present invention. This is one in which the high-frequency module of the present invention is used in a high-frequency circuit portion of a mobile phone. In the figure, reference numeral 20 denotes a high frequency module of the present invention, which includes a duplexer DPX, amplifiers AMPa, AMPb, AMPc, bandpass filters BPFa, BPFb, mixers MIXa, MIXb, an intermediate frequency filter IF, and a PLL synthesizer. A high frequency circuit portion including a modulator and a demodulator is formed.
[0033]
Next, the operation will be described. The signal received from the antenna is amplified by the amplifier AMPb via the duplexer DPX, and then only the signal in the necessary band is extracted by the bandpass filter BPFb, and mixed with the signal from the PLL synthesizer by the mixer MIXb. An intermediate frequency band is extracted from the mixed signal by an intermediate frequency filter IF, amplified by an amplifier AMPc, a received signal is demodulated by a demodulator, and output to a multiplexing control circuit outside the high frequency module. On the other hand, the transmission signal input from the multiplexing control circuit is modulated by the modulator and mixed with the signal from the PLL synthesizer by the mixer MIXa. Only the high-frequency band signal is extracted from the mixed signal by the bandpass filter BPFa, amplified by the amplifier AMPa, and sent to the antenna via the duplexer DPX.
[0034]
In addition to the high frequency module, the communication device includes a multiplexing control circuit, a voice codec, a CPU, a microphone, a speaker, a display, a key switch, and a vibrator. The audio codec encodes the signal from the microphone, sends it to the multiplexing control circuit, converts the demodulated signal from the multiplexing control circuit into an audio signal, and gives it to the speaker. The CPU controls the multiplexing control circuit, reads the state of the key switch, outputs a display signal to the display, and gives a drive signal to the vibrator.
[0035]
As described above, since the high-frequency circuit portion of the communication device is formed in the high-frequency module of the present invention, high-density mounting is possible, and a small and lightweight communication device can be obtained.
[0036]
In the above embodiment, the portion formed in the high-frequency module of the present invention is only the high-frequency circuit portion of the communication device, but is not limited to this, and may include other portions, for example, the entire circuit May be formed integrally with the high-frequency module of the present invention, and a metal case may be attached only to a portion that requires metal shielding. As a result, higher-density mounting becomes possible, contributing to a reduction in size and weight and cost.
[0037]
In the above-described embodiment, the case where the high-frequency module is used in a mobile phone has been described. However, the present invention is not limited to this and can be applied to all communication devices having a high-frequency circuit portion. .
[0038]
【The invention's effect】
As described above, the high frequency module of the present invention is provided with soldering terminals in a part including the four corners of the metal case, solder lands corresponding to the electronic component mounting surface of the board, and soldering the metal case to the board. The metal case can be fixed even on a thin substrate, and the metal case can be joined to the side surface and end surface of the substrate without bonding, or the metal case can be joined without providing a recess, so that the production efficiency can be improved and the manufacturing cost can be reduced. effective.
[0039]
In addition, since the communication device of the present invention has at least the high-frequency circuit portion formed in the high-frequency module of the present invention, high-density mounting is possible, and a small and lightweight communication device can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view of a high-frequency module according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view of a high-frequency module according to an embodiment of the present invention.
FIG. 3 is a block configuration diagram of a communication apparatus according to an embodiment of the present invention.
FIG. 4 is a perspective view showing an example of a conventional high-frequency module.
FIG. 5 is an exploded perspective view showing an example of a conventional high-frequency module.
FIG. 6 is an exploded perspective view showing another example of a conventional high-frequency module.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 High frequency module 12 Board | substrate 14 Metal case 16 Electronic component 12a, 12b, 12c, 12d, 12e, 12f Solder land 14a, 14b, 14c, 14d, 14e, 14f Soldering terminal 20 High frequency module mounted in the communication apparatus

Claims (6)

In a high-frequency module comprising a substrate on which an electronic component is mounted and a metal case attached to the substrate so as to cover the electronic component, an incision is provided in a part including four corners of the metal case. And a soldering terminal formed in an L shape, provided with a land corresponding to the soldering terminal on the electronic component mounting surface of the board, and soldering the soldering terminal to the land. A high-frequency module. A soldering terminal is also provided in the middle part of the four corners of the metal case, a land corresponding to the soldering terminal is provided on the electronic component mounting surface of the substrate, and the soldering terminal is soldered to the land. The high-frequency module according to claim 1. The high frequency module according to claim 1 or 2, wherein at least one bending direction of the solder terminals of the metal case is changed. The thermal expansion coefficient of the metal case may be smaller than the thermal expansion coefficient of the substrate, a high frequency module according to any one of claims 1 to 3. The high-frequency module according to claim 4 , wherein a difference in coefficient of thermal expansion between the metal case and the substrate is 5 ppm or less. A communication device having a high-frequency circuit portion, wherein at least the high-frequency circuit portion is formed in the high-frequency module according to any one of claims 1 to 5 .

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