JP2007067002A - High frequency module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency module capable of making minimum a gap between a ceiling of a shield case and a packaged component on a printed wiring board and of making the size small and the height low. <P>SOLUTION: The high frequency module 1 comprises: a printed wiring board 10 on which a single or a plurality of electronic components are mounted inclusive of a main electronic component 11b having a flat upper surface; and a shield case 12 having a flat ceiling and electromagnetically shielding at least a part of electronic components including the main electronic component 11b. In the high frequency module 1, the ceiling of the shield case 12 is bonded to the upper surface of the main electronic component 11b with an insulating adhesive agent 13 containing an insulating filler 14, whereby the shield case 12 is mounted on the printed wiring board 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high-frequency module including a shield case used for portable communication devices and the like.

  High-frequency modules used in portable communication devices and the like generally have a character that is sensitive to noise because they handle high frequencies. For this reason, a shield case is used for a high frequency module from the viewpoint of noise countermeasures. In the high frequency module in which this shield case is used, a structure in which the electronic component attached to the substrate is covered with the shield case is employed. For this reason, it is necessary to attach the shield case to a substrate on which electronic components are attached. Various methods have been devised for attaching the shield case to the substrate (see, for example, Patent Documents 1 and 2). .

  6 to 8 show an example of a method of attaching a shield case to a substrate in a conventional high-frequency module. In this example, in FIG. 6 to FIG. 8, after electronic components 101a, 101b, and 101c are mounted on a printed wiring board 100 on which a wiring pattern 100a having a ground potential is formed, these electronic components 101a, 101b, and 101c are covered. In this way, the lower end 102a of the side wall of the metal shield case 102 provided with the ceiling is joined to the ground electrode 100a connected to the wiring pattern of the ground potential of the printed wiring board 100.

  The shield case 102 has an open bottom surface and is provided with protruding portions 102b that protrude downward on opposite side walls. Further, the printed wiring board 100 is provided with concave portions 100b made of metal on the opposite side surfaces, and the protrusions 102b of the metal shield case 102 are soldered to the concave portions 100b of the printed wiring board 100. Thus, the shield case 102 is attached to the printed wiring board 100.

That is, the protrusion 102b of the shield case 102 is soldered to the recess 100b of the printed wiring board 100, so that the lower end 102a of the side wall of the shield case 102 is connected to the wiring pattern of the ground potential of the printed wiring board 100. The shield case 102 is mounted on the printed wiring board 100 in a state of being pressed against the electrode 100a. Similarly, the shield case described in Patent Document 1 is mounted on the printed wiring board. Further, in the shield case described in Patent Document 2, a hole for mounting the shield case is provided in the printed circuit board, and a shield or the like provided in the shield case is fitted into the hole for mounting the shield case. The case is attached to the printed wiring board.
Japanese Patent Laid-Open No. 9-307261 JP 2005-136002 A

  However, in the above-described conventional high-frequency module, if the space between the ceiling part of the shield case and the component mounted on the printed wiring board is not sufficiently secured, the ceiling part of the shield case and the printed wiring board There is a risk of electrical short-circuiting due to contact with components mounted on the board.

  For this reason, it is necessary to provide a sufficient gap between the ceiling part of the shield case and the mounted parts of the printed wiring board so that the ceiling part of the shield case and the parts mounted on the printed wiring board do not come into contact with each other. However, there is a problem that the height of the shield case cannot be reduced and it is difficult to reduce the size and height of the high-frequency module.

  Accordingly, the present invention has been made to solve the above-described problems, and can minimize the gap between the ceiling portion of the shield case and the mounted component of the printed wiring board, and can be downsized and reduced in height. An object of the present invention is to provide a high-frequency module that can be realized.

  The high-frequency module of the present invention includes a printed wiring board to which a single or a plurality of electronic components including a main electronic component having a flat upper surface are attached, and a flat ceiling and at least a part of the electronic components including the main electronic component. And a shield case that electromagnetically shields. This high-frequency module is characterized in that the shield case is attached to the printed circuit board by bonding the ceiling of the shield case to the upper surface of the main electronic component with an insulating adhesive containing an insulating filler.

  According to the above high-frequency module, the ceiling of the shield case used in the high-frequency module is bonded to the upper surface of the main electronic component attached to the printed wiring board with an insulating adhesive containing an insulating filler. ing. Therefore, since the gap between the ceiling of the shield case and the main electronic component that is the mounting component of the printed wiring board is filled with an insulating adhesive containing an insulating filler, the ceiling of the shield case and the main electronic component There is no fear of contact, and sufficient insulation can be ensured between the shield case and the main electronic component. In addition, the height of the gap between the ceiling of the shield case and the upper surface of the main electronic component can be reduced to substantially the same size as the insulating filler contained in the insulating adhesive. Can be reduced in size and height.

  In the above high frequency module, it is reasonable to use the tallest electronic component among the electronic components electromagnetically shielded by the shield case as the main electronic component.

  In the above high-frequency module, the printed wiring board is preferably provided with a ground electrode on the surface of the printed wiring board, and the shield case is preferably provided with a side wall continuous from the ceiling of the shield case. In this way, by bonding the ceiling of the shield case to the upper surface of the main electronic component, the lower end of the side wall of the shield case can be pressed and electrically connected to the ground electrode of the printed wiring board. Therefore, the shield case and the ground electrode of the printed wiring board can be electrically connected.

  In the above high frequency module, it is preferable that the side wall of the shield case be bent. In this case, since the side wall of the shield case is bent, the side wall is urged to extend. By this urging, the lower end of the side wall of the shield case is pressed against the ground electrode of the printed wiring board. Power can be strengthened. Therefore, the electrical connection between the shield case and the ground electrode of the printed wiring board can be made more reliable.

  In addition, as the above-described high-frequency module, a plurality of different electronic component groups that are composed of some electronic components including the main electronic component and are electromagnetically shielded by the shield case are formed on the printed wiring board. A high-frequency module can also be configured.

  Further, when the above-described high-frequency module is incorporated in an electronic device or the like, it may be mounted on a mother wiring board of the electronic device or the like. In this case, it is preferable that a part of the shield case mounted on the printed wiring board is electrically connected to the ground electrode of the mother wiring board. By doing in this way, the electromagnetic shielding effect in a high frequency module can be improved further.

  According to the present invention, the ceiling of the shield case used in the high-frequency module is bonded to the upper surface of the main electronic component attached to the printed wiring board with the insulating adhesive containing the insulating filler. Therefore, since the gap between the ceiling of the shield case and the main electronic component that is the mounting component of the printed wiring board is filled with an insulating adhesive containing an insulating filler, the ceiling of the shield case and the main electronic component There is no fear of contact, and sufficient insulation can be ensured between the shield case and the main electronic component. In addition, the height of the gap between the ceiling of the shield case and the upper surface of the main electronic component can be reduced to substantially the same size as the insulating filler contained in the insulating adhesive. Can be reduced in size and height.

  Hereinafter, a high frequency module according to an embodiment of the present invention will be described in detail with reference to the drawings.

<Embodiment 1>
FIG. 1 is an exploded perspective view showing the structure of the high-frequency module 1 according to Embodiment 1, and FIG. 2 is a cross-sectional view thereof. 1 and 2, the high-frequency module 1 according to Embodiment 1 includes a printed wiring board 10 on which electronic components are mounted, and a shield case 12 that electromagnetically shields the electronic components mounted on the printed wiring board 10. It is configured.

  The printed wiring board 10 is a multilayer board formed of glass epoxy resin, ceramic, or the like, and conductive wiring patterns are formed on the front and back surfaces and the inner layer surface of the printed wiring board 10. This wiring pattern includes a ground potential wiring pattern and a ground electrode 10a connected to the ground potential wiring pattern. As shown in FIG. 1, the ground electrodes 10 a are formed at the four corners of the surface of the printed wiring board 10.

  On the printed wiring board 10, passive component elements such as capacitors, resistors, and inductors and active elements such as crystal resonators, transistors, and IC chips are mounted as electronic components. In FIG. 1 and FIG. 2, for the sake of clarity, only three electronic components 11a, 11b, and 11c are displayed as these electronic components. Among these three electronic components, the electronic component 11b is the tallest electronic component and corresponds to the main electronic component described above. As the electronic component 11, a molded part such as an IC chip is generally used.

  The shield case 12 is made of metal such as aluminum and has a box shape with an open bottom surface. The shield case 12 includes a ceiling and a side wall, and a leg portion 12a at the lower end of the side wall. The height of the shield case 12 is slightly higher than the height of the electronic component 11b, which is the tallest electronic component mounted on the printed wiring board 10. The shield case 12 is attached to the printed wiring board 10 so as to cover all the electronic components 11a, 11b, and 11c mounted on the surface of the printed wiring board 10. Electromagnetic shielding is applied to all the electronic components. The shield case 12 is attached to the printed wiring board 10 as follows.

  That is, insulation is uniform in size on the upper surface of the electronic component 11b which is the tallest electronic component mounted on the printed circuit board 10 and its periphery (size is 25 μm to 100 μm, size tolerance is about ± 5 μm). An insulating adhesive 13 containing a conductive filler 14 (material is an insulating material such as silica) is applied to cover the electronic component 11b and the like. At this time, the insulating adhesive 13 is applied to the upper surface of the electronic component 11b so that the thickness is uniform. In this state, with the shield case 12 facing down, all the electronic components 11a, 11b, and 11c mounted on the surface of the printed wiring board 10 are covered. As described above, the printed wiring board 10 is covered from above. Then, the shield case 12 is pressed against the printed wiring board 10 so that the lower surface of the leg portion 12a of the shield case 12 overlaps the upper surface of the ground electrode 10a formed at the four corners of the surface of the printed wiring board 10. This state is maintained until the adhesive 13 is cured.

  As the insulating adhesive 13 used above, an adhesive made of a high heat-resistant resin such as an epoxy resin or a polyimide resin that does not deteriorate even at 230 to 260 ° C. is used. Therefore, the insulating adhesive 13 can sufficiently withstand the heat generation of the electronic component 11b to which the insulating adhesive 13 is applied.

  Moreover, since the insulating adhesive 13 used above contains the insulating filler 14 having a uniform size, the viscosity of the insulating adhesive 13 is improved, and the insulating adhesive 13 is insulated when applied. It is possible to prevent the adhesive 13 from dripping or flowing. Accordingly, the shape of the insulating adhesive 13 can be prevented from changing after application, and the shield case 12 can be attached to the printed wiring board 10 with high accuracy.

  Further, as described above, the insulating filler 14 has a size of 25 μm to 100 μm and a size tolerance of about ± 5 μm, so that a gap between the ceiling of the shield case 12 and the upper surface of the electronic component 11b is formed. The insulating filler 14 can be made narrower by aligning the sizes (for example, by setting the size to 25 μm). Therefore, the height of the shield case 12 is formed slightly higher than the height of the electronic component 11b that is the tallest electronic component mounted on the printed wiring board 10. By aligning the sizes of the two, the height of the shield case 12 can be minimized while maintaining insulation.

  When the shield case 12 is attached to the printed circuit board 10, the lower surface of the leg 12 a of the shield case 12 is overlapped with the upper surface of the ground electrode 10 a formed at the four corners of the surface of the printed circuit board 10. Then, the shield case 12 is pressed against the printed wiring board 10 to cure the insulating adhesive 13. Therefore, the contact between the leg portion 12a of the shield case 12 and the ground electrode 10a of the printed wiring board 10 can be made sufficiently sufficiently electrically. Further, since the shield case 12 is electrically connected to the ground electrode 10a connected to the ground potential wiring pattern on the printed wiring board 10, the shield case 12 can be kept at the ground potential.

  According to the high frequency module 1 described above, the ceiling of the shield case 12 used in the high frequency module 1 includes an insulating filler 14 on the upper surface of the electronic component 11b attached to the printed wiring board 10. Bonded with an adhesive 13. Therefore, since the gap between the ceiling of the shield case 12 and the electronic component 11b that is the mounting component of the printed wiring board 10 is filled with the insulating adhesive 13 containing the insulating filler 14, the shield case 12 There is no fear that the ceiling and the electronic component 11b come into contact with each other, and sufficient insulation can be ensured between the shield case 12 and the electronic component 11b. Further, the height of the gap between the ceiling of the shield case 12 and the upper surface of the electronic component 11b can be reduced to substantially the same size as the insulating filler 14 contained in the insulating adhesive 13. Thus, the high-frequency module 1 can be reduced in size and height.

  In the high-frequency module 1 described above, the leg portion 12a of the shield case 12 and the ground electrode 10a of the printed wiring board 10 are simply brought into contact with each other, but the leg of the shield case 12 is strengthened in order to enhance the ground potential. The portion 12a and the ground electrode 10a of the printed wiring board 10 may be soldered.

<Embodiment 2>
FIG. 3 is a cross-sectional view showing the structure of the high-frequency module 2 in the second embodiment. The high-frequency module 2 is almost the same as the high-frequency module 1 in the first embodiment, except that the shape of the shield case 12 is different, and the rest is the same as the high-frequency module 1 in the first embodiment. .

  In the high frequency module 2 described above, the side wall 12b of the shield case 12 is bent in a “<” shape so as to bulge outward as shown in FIG. Since the side wall 12b of the shield case 12 is bent in a "<" shape, the side wall 12b is urged so as to extend. By this urging, the printed wiring board at the lower end of the side wall 12b of the shield case 12 is urged. The pressure contact force with respect to the 10 ground electrodes 10a can be increased. Therefore, the electrical connection between the shield case 12 and the ground electrode 10a of the printed wiring board 10 can be made more reliable.

<Embodiment 3>
FIG. 4 is a side view showing the structure of the high-frequency module 3 in the third embodiment. In the high frequency module 3, for example, an electronic circuit constituting the high frequency module 3 is divided into a plurality of blocks on a single printed wiring board 10, and an independent shield is provided for each of the plurality of blocks. The case is electromagnetically shielded.

  That is, in FIG. 4, the high frequency module 3 according to the third embodiment is configured with an electronic component including at least an electronic component to which the insulating adhesive 13 containing the insulating filler 14 is applied and the ceiling of the shield case 12 is bonded. A plurality of different electronic component groups electromagnetically shielded by the shield case 12 bonded to the electronic component is a high-frequency module formed on one printed wiring board 10. As described above, a high-frequency module including a plurality of shield cases 12 can be configured on one printed wiring board 10.

<Embodiment 4>
FIG. 5 is a cross-sectional view showing the structure of high-frequency module 4 in the fourth embodiment. The high-frequency module 4 is obtained by mounting the high-frequency module 1 in the first embodiment described above on a mother wiring board 15 such as an electronic device in which the high-frequency module 1 is incorporated. In the high-frequency module 4, a part of the shield case 12 attached to the printed wiring board 10 is electrically connected to the ground electrode 15 a of the mother wiring board 15. By doing in this way, the electromagnetic shielding effect in the high frequency module 4 can be improved further.

  In each of the above embodiments, the high-frequency module is configured such that all the electronic components mounted on the printed wiring board 10 are electromagnetically shielded by the shield case 12 attached to the printed wiring board 10. Of the electronic components mounted on the printed wiring board 10, only some of the electronic components may be electromagnetically shielded.

FIG. 3 is an exploded perspective view showing the structure of the high frequency module in the first embodiment. 2 is a cross-sectional view showing the structure of the high-frequency module in Embodiment 1. FIG. 6 is a cross-sectional view showing a structure of a high-frequency module according to Embodiment 2. FIG. FIG. 5 is a side view showing the structure of a high frequency module in a third embodiment. FIG. 6 is a cross-sectional view showing a structure of a high frequency module in a fourth embodiment. It is the disassembled perspective view which showed the structure of the high frequency module in a prior art example. It is a side view of the high frequency module in a prior art example. It is sectional drawing which showed the structure of the high frequency module in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High frequency module 2 High frequency module 3 High frequency module 4 High frequency module 10 Printed wiring board 10a Ground electrode 11a Electronic component 11b Electronic component 11c Electronic component 12 Shield case 12a Leg part 12b Side wall 13 Insulating adhesive 14 Filler 15 Mother wiring board 15a Ground electrode DESCRIPTION OF SYMBOLS 100 Printed wiring board 100a Ground electrode 100b Concave part 101a Electronic component 101b Electronic component 101c Electronic component 102 Shield case 102a Side wall lower end 102b Protrusion part

Claims (6)

A printed wiring board on which one or a plurality of electronic components including a main electronic component having a flat upper surface are mounted, and a shield having a flat ceiling and electromagnetically shielding at least a part of the electronic components including the main electronic component A high frequency module comprising a case,
The shield case is mounted on the printed circuit board by bonding a ceiling of the shield case to an upper surface of the main electronic component with an insulating adhesive containing an insulating filler. module.   The high-frequency module according to claim 1, wherein the main electronic component is the tallest electronic component among the electronic components electromagnetically shielded by the shield case. The printed wiring board includes a ground electrode on the surface of the printed wiring board, and the shield case includes a side wall that extends from the ceiling of the shield case.
3. The lower end of the side wall of the shield case is electrically connected to the ground electrode of the printed wiring board by pressing the ceiling of the shield case to the upper surface of the main electronic component. The high-frequency module described.   The side wall of the shield case is bent, and the side wall of the shield case is urged to be extended by the bending, and the bias of the printed wiring board at the lower end of the side wall of the shield case is urged by the urging. The high frequency module according to claim 3, wherein the pressure contact force with respect to the ground electrode is enhanced.   5. The plurality of different electronic component groups that are configured by a part of the electronic components including the main electronic component and are electromagnetically shielded by the shield case are formed on the printed wiring board. The high frequency module of any one of Claims.   2. The printed wiring board is mounted on a mother wiring board, and a part of the shield case attached to the printed wiring board is electrically connected to a ground electrode of the mother wiring board. The high frequency module of any one of -5.

Images