Module

Abstract

This module (101) comprises: a substrate (51) having a substrate first surface (51a); an inductor (31) having a winding axis (31x) and mounted on the substrate first surface (51a); and a sealing resin (6a) disposed so as to cover the inductor (31) and the substrate first surface (51a). The sealing resin (6a) has a sealing resin first surface (61) that intersects with an extension line of the winding axis (31x). A metal foil (15) is disposed so as to cover a first region of the sealing resin first surface (61), the first region including a point at which the extension line of the winding axis (31x) intersects the sealing resin first surface (61) and corresponding to a region in which the inductor (31) is projected onto the sealing resin first surface (61). The metal foil (15) is grounded.

Description

Module

[0001] The present invention relates to a module.

[0002] In a module that handles high frequencies, components mounted on a substrate are covered with a sealing resin, and a shield film is formed so as to cover the surface of this sealing resin. The shield film is intended to shield electromagnetic waves. The shield film is formed using a thin film forming technique such as a sputtering method.

[0003] However, when forming a shield film by these methods, the portion of the shield film that covers the upper surface of the sealing resin tends to be thicker than the portion that covers the side surface. If an attempt is made to make the shield film covering the side surface of the sealing resin sufficiently thick, the shield film covering the upper surface of the sealing resin becomes unnecessarily thick, which has hindered the reduction in the height of the module. In order to solve this problem, in addition to the first shield film that covers the upper surface and the side surface of the sealing resin, forming a second shield film that covers the side surface of the sealing resin is described in International Publication WO2016 / 186103A1 (Patent Document 1).

[0004] WO2016 / 186103A1

[0005] When forming a shield film by the sputtering method, the module becomes hot. Also, with this method, it is difficult to form a shield film on only a part of the surface of the sealing resin. Furthermore, even if an attempt is made to thicken the shield film by the sputtering method, the thickness of the obtained shield film is at most about 5 μm, which is not a sufficient thickness.

[0006] Therefore, an object of the present invention is to provide a module that realizes shield performance of a necessary degree at necessary locations.

[0007] To achieve the above objective, a module according to the present invention comprises a substrate having a first substrate surface, an inductor having a winding shaft and mounted on the first substrate surface, and a sealing resin disposed to cover the inductor and the first substrate surface. The sealing resin has a first sealing resin surface where the extensions of the winding shaft intersect. A metal foil is disposed on the first sealing resin surface so as to cover a first region that includes the point where the extensions of the winding shaft intersect the first sealing resin surface and corresponds to the region obtained by projecting the inductor onto the first sealing resin surface. The metal foil is grounded.

[0008] According to the present invention, since the metal foil is arranged to cover a first region which is a part of the surface of the sealing resin, the required degree of shielding performance can be achieved where needed.

[0009] This is a cross-sectional view of the module in Embodiment 1 according to the present invention. This is a plan view of the module in Embodiment 1 according to the present invention. This is a side view of the module in Embodiment 1 according to the present invention. This is a diagram in which the outline of the first region is shown with a thick line in Figure 3. This is a cross-sectional view of the module in Embodiment 2 according to the present invention. This is a plan view of the module in Embodiment 2 according to the present invention. This is a side view of the module in Embodiment 2 according to the present invention. This is a cross-sectional view of the module in Embodiment 3 according to the present invention. This is a plan view of the module in Embodiment 3 according to the present invention. This is a cross-sectional view of the first modified example of the module in Embodiment 3 according to the present invention. This is a cross-sectional view of the second modified example of the module in Embodiment 3 according to the present invention. This is a cross-sectional view of the third modified example of the module in Embodiment 3 according to the present invention. This is a cross-sectional view of the module in Embodiment 4 according to the present invention. This is a cross-sectional view of the first modified example of the module in Embodiment 4 according to the present invention. This is a cross-sectional view of the second modified example of the module in Embodiment 4 according to the present invention.

[0010] The dimensional ratios shown in the drawings do not necessarily accurately reflect reality, and may be exaggerated for illustrative purposes. In the following explanation, the concepts of "up" or "down" do not necessarily refer to absolute up or down, but rather to relative up or down within the illustrated orientation.

[0011] (Embodiment 1) A module in Embodiment 1 according to the present invention will be described with reference to Figures 1 to 3. A cross-sectional view of module 101 in this embodiment is shown in Figure 1. A plan view of module 101 is shown in Figure 2. However, for the sake of explanation, Figure 2 shows the state with the sealing resin 6a removed. Therefore, in Figure 2, the group of components that are normally covered and hidden by the sealing resin 6a are visible.

[0012] The module 101 in this embodiment comprises a substrate 51, an inductor 31, and a sealing resin 6a. The substrate 51 has a first substrate surface 51a. The inductor 31 has a winding shaft 31x and is mounted on the first substrate surface 51a. The sealing resin 6a is arranged to cover the inductor 31 and the first substrate surface 51a. The sealing resin 6a has a first sealing resin surface 61 where the extension of the winding shaft 31x intersects. A metal foil 15 is arranged to cover a first region of the first sealing resin surface 61. The first region includes the point where the extension of the winding shaft 31x intersects the first sealing resin surface 61 and corresponds to the region obtained by projecting the inductor 31 onto the first sealing resin surface 61. The metal foil 15 is grounded.

[0013] The inductor 31 incorporates a coil wiring 31c. The shape of the coil wiring 31c determines the direction of the winding axis 31x. In Figure 1, the shape of the coil wiring 31c is shown schematically, and the actual detailed shape of the coil wiring 31c may not be exactly as shown here. In the example shown here, the winding axis 31x of the inductor 31 is parallel to the first surface 51a of the substrate. Therefore, the first surface 61 of the sealing resin where the extension of the winding axis 31x intersects is the side surface of the sealing resin 6a. The metal foil 15 is arranged to cover a part of the side surface of the sealing resin 6a. The metal foil 15 does not cover the entire side surface of the sealing resin 6a, but only the first region of the side surface of the sealing resin 6a. That is, this side surface, which is selected as the first surface 61 of the sealing resin 6a from among several surfaces of the sealing resin 6a, also includes regions other than the first region. To put it another way, the first surface 61 of the sealing resin includes regions not covered by the metal foil 15. The metal foil 15 is attached to the side surface of the sealing resin 6a via a bonding material 16. The metal foil 15 may be manufactured in advance at another location and then brought to this location and attached. In this way, if the metal foil 15 is manufactured in advance at another location, it becomes possible to prepare metal foil 15 with a thickness of, for example, about 10 μm to about 100 μm. Compared to the shield film formed by the conventional sputtering method, where the thickness of the metal film was at most about 5 μm, by adopting the metal foil 15 described here, it is possible to obtain a metal shielding member that is more than twice as thick as conventional ones. By making it possible to apply shielding with such a sufficiently thick member, it becomes possible to strengthen the shield in the desired area. Furthermore, the material of the metal foil 15 may be, for example, copper, aluminum, nickel, gold, or silver, and among these, copper is preferred. That is, the metal foil 15 is preferably copper foil.

[0014] In the example shown in Figure 1, strictly speaking, there are two surfaces on the sealing resin 6a where the extensions of the winding shaft 31x intersect, namely the left end and the right end in Figure 1. When there are two or more surfaces on which the extensions of the winding shaft 31x intersect, it is preferable that the first surface 61 of the sealing resin is the surface closest to the inductor 31 among the two or more surfaces. In other words, as shown in this embodiment, the sealing resin 6a has two or more surfaces on which the extensions of the winding shaft 31x intersect, and it is preferable that the first surface 61 of the sealing resin is the surface closest to the inductor 31 among the two or more surfaces.

[0015] In addition to the inductor 31, components 32, 33, 34, etc. may also be mounted on the first surface 51a of the substrate. The first surface 51a of the substrate has a recess 12. The recess 12 can also be understood as a locally lowered portion of the first surface 51a of the substrate. The recess 12 is not necessarily located away from the outer periphery of the first surface 51a of the substrate. As shown in Figures 1 and 2, the recess 12 may be located in contact with the edge of the substrate 51. In this case, a part of the outer periphery of the recess 12 is adjacent to a raised portion, and the other part forms the edge of the substrate 51. In this embodiment, as shown in Figure 2, the recess 12 is located at the corner of the substrate 51. The inductor 31 is mounted on the first surface 51a of the substrate inside the recess 12. An electrode 24 is placed on the bottom surface of the recess 12. The external terminals of the inductor 31 are electrically connected to the electrode 24. On the other hand, an electrode 23 is provided on the side surface of the substrate 51. The electrode 23 is a ground electrode. The metal foil 15 is electrically connected to the electrode 23 via a conductive bonding material 26. The conductive bonding material 26 may be, for example, solder. In this example, the conductive bonding material 26 is electrically connected to one end of the metal foil 15.

[0016] Inductors are typically the tallest components among those mounted on a circuit board. As illustrated here, to reduce the overall height of the module, a stepped area can be created on the surface of the circuit board, resulting in a locally lowered region, where the inductor is mounted.

[0017] The group of components arranged on the first surface 51a of the circuit board includes three groups: common devices, transmitting devices, and receiving devices. Common devices include, for example, antennas and switches. Transmitting devices include, for example, power amplifiers (PAs) and matching circuits. Receiving devices include, for example, low noise amplifiers (LNAs) and matching circuits. Components belonging to these three groups are each mounted in a separate area.

[0018] As shown in Figure 1, the substrate 51 has a second substrate surface 51b, which is the surface opposite to the first substrate surface 51a. Components 35 and the like are mounted on the second substrate surface 51b. A sealing resin 6b is arranged to cover the second substrate surface 51b and the sides of the components 35. In this example, the side of the component 35 furthest from the second substrate surface 51b is exposed from the sealing resin 6b. Here, an example is shown where the side of the component 35 furthest from the second substrate surface 51b is exposed from the sealing resin 6b, but the side of the component 35 furthest from the second substrate surface 51b may also be covered by the sealing resin 6b.

[0019] Multiple connecting conductors 7 are electrically connected to the second surface 51b of the substrate. The connecting conductors 7 are, for example, columnar conductors. The connecting conductors 7 are arranged to penetrate the sealing resin 6b. The side of the connecting conductors 7 that is farther from the second surface 51b of the substrate is exposed from the sealing resin 6b.

[0020] Figure 3 shows the view from the side indicated by arrow 91 in Figure 2. When viewed from this orientation, if the inductor 31 is represented by a dashed line, other components to the left of the inductor 31 should also be represented by dashed lines, but these components are omitted from the illustration. The entire front surface of the sealing resin 6a is the first sealing resin surface 61. The area of ​​the first sealing resin surface 61 covered by the metal foil 15 is the first region. Figure 4 shows the outline of the first region, indicated by a thick line. The first region 61z corresponds to the area obtained by projecting the inductor 31 onto the first sealing resin surface 61. Here, "corresponds" does not necessarily mean that it is the same as the area onto which the inductor 31 is projected. The first region 61z may be a region slightly larger than the area obtained by projecting the inductor 31 onto the first sealing resin surface 61. As shown in this example, a part of the metal foil 15 may extend into an area that does not correspond to the first region 61z.

[0021] In this embodiment, the metal foil 15 is arranged to cover a first region 61z, which is a part of the surface of the sealing resin 6a, so that the required level of shielding performance can be achieved where needed. The metal foil 15 may be manufactured elsewhere in advance and then brought to this location and attached, so that it can be made to a desired thickness, and the required level of shielding performance can be easily achieved.

[0022] In conventional modules, a configuration in which a shielding film is formed to surround and cover the entire outer surface of the encapsulating resin was considered. However, in such a configuration, parasitic capacitance occurs between the components mounted on the substrate surface and the shielding film formed on the outer surface of the encapsulating resin. To avoid this problem, components had to be mounted on the substrate surface at a certain distance from the outer surface of the encapsulating resin. However, in this embodiment, instead of forming a shielding film to cover the entire outer surface of the encapsulating resin, metal foil of the required thickness can be placed only where necessary as a shielding film. This avoids the formation of a shielding film in unnecessary areas, thus reducing the problem of parasitic capacitance and increasing the freedom of component mounting positions on the substrate surface. As a result, it becomes possible to reduce the height and area of ​​the module.

[0023] (Embodiment 2) A module in Embodiment 2 based on the present invention will be described with reference to Figures 5 to 7. A cross-sectional view of module 102 in this embodiment is shown in Figure 5. A plan view of module 102 is shown in Figure 6. However, Figure 6 is the same as Figure 2 shown in Embodiment 1 in that it shows the state with the sealing resin 6a removed for the sake of explanation.

[0024] Many of the basic configurations of module 102 are the same as those of module 101 shown in Embodiment 1. In module 101, the winding axis 31x of the inductor 31 was parallel to the first surface 51a of the substrate, but in module 102, the winding axis 31x of the inductor 31 is perpendicular to the first surface 51a of the substrate. Due to this difference, the metal foil 15 in module 102 is different from that in module 101.

[0025] In this embodiment, the first sealing resin surface 61 is the surface of the sealing resin 6a that is furthest from the first substrate surface 51a. In the orientation shown in Figure 5, the first sealing resin surface 61 is the upper surface of the sealing resin 6a. Figure 7 shows the view in the direction of arrow 92 in Figure 6. When viewed in this orientation, if the inductor 31 is represented by a dashed line, other components to the left of the inductor 31 should also be represented by dashed lines, but in Figure 7, components other than the inductor 31 are omitted from the illustration.

[0026] The metal foil 15 is bonded to the surface of the sealing resin 6a via a bonding material 16. The metal foil 15 includes a main body and a wiring portion. The main body covers a part of the upper surface of the sealing resin 6a, which is the first sealing resin surface 61, i.e., a first region. The first region includes the point where the extension of the winding shaft 31x intersects the first sealing resin surface 61, and corresponds to the region obtained by projecting the inductor 31 onto the first sealing resin surface 61. In Figure 6, the first region is the area of ​​the first sealing resin surface 61 that is covered by the metal foil 15.

[0027] On the other hand, the wiring section extends from the end of the main body. The wiring section is linear and is arranged along the side surface of the sealing resin 6a. An electrode 23 is provided on the side surface of the substrate 51. The electrode 23 is a ground electrode. The end of the wiring section furthest from the main body is electrically connected to the electrode 23 via a conductive bonding material 26.

[0028] In this embodiment, the metal foil 15 is arranged to cover a first region, which is a part of the surface of the sealing resin 6a, so that the required degree of shielding performance can be achieved where needed. As is clear from Figures 5 and 6, in this embodiment, the upper surface of the sealing resin 6a includes regions other than the first region. That is, the first surface 61 of the sealing resin includes regions not covered by the metal foil 15.

[0029] As shown in Embodiments 1 and 2, the first sealing resin surface 61 is preferably the surface of the sealing resin 6a that is farther from the first substrate surface 51a, or it is a side surface of the sealing resin 6a.

[0030] (Embodiment 3) A module in Embodiment 3 according to the present invention will be described with reference to Figures 8 to 9. A cross-sectional view of module 103 in this embodiment is shown in Figure 8. A plan view of module 103 is shown in Figure 9.

[0031] In module 103, the winding axis 31x of the inductor 31 is parallel to the first surface 51a of the substrate. Therefore, the side surface of the sealing resin 6a is the first surface 61 of the sealing resin. Module 103 includes a shielding film 8 that covers the surface and side of the sealing resin 6a that is farther from the first surface 51a of the substrate. The metal foil 15 covers a portion of the shielding film 8. The shielding film 8 may further cover the side surface of the substrate 51. The shielding film 8 may further cover the side surface of the sealing resin 6b. An electrode 25 is provided on the side surface of the substrate 51. The electrode 25 is a ground electrode. The shielding film 8 is electrically connected to the electrode 25. The shielding film 8 is a metal film formed, for example, by sputtering.

[0032] In this embodiment, the first sealing resin surface 61 is the side surface of the sealing resin 6a. The first region is the area of ​​the side surface of the sealing resin 6a that is covered by the metal foil 15.

[0033] The metal foil 15 is bonded to the shield film 8 via a bonding material 16. A conductive bonding material 26i is positioned adjacent to the bonding material 16. The metal foil 15 is electrically connected to the shield film 8 via the conductive bonding material 26i.

[0034] In this embodiment as well, the same effects as those described in Embodiment 1 can be obtained. While obtaining the shielding effect of the shielding film 8 that covers the entire structure, the inclusion of the metal foil 15 further enables the realization of the required level of shielding performance in the necessary locations.

[0035] When the winding axis 31x of the inductor 31 is perpendicular to the first surface 51a of the substrate, a configuration like the module 104 shown in Figure 10 can be considered. The module 104 covers a part of the shield film 8 on the upper surface of the sealing resin 6a. In this case, the first surface 61 of the sealing resin is the upper surface of the sealing resin 6a. The region of the upper surface of the sealing resin 6a, which is the first surface 61 of the sealing resin, that is covered by the metal foil 15 is the first region.

[0036] Furthermore, in order to further reduce the profile, a configuration such as module 105 shown in Figure 11 can also be considered. In module 105, the sealing resin 6a has a recess 27 on the side furthest from the first substrate surface 51a, and the metal foil 15 is placed inside the recess 27. By adopting this configuration, the profile can be reduced.

[0037] Alternatively, a configuration like the module 106 shown in Figure 12 is also possible. In module 106, the sealing resin 6a has an inclined portion 28 on at least a part of the surface furthest from the first substrate surface 51a, and the metal foil 15 is placed on the inclined portion 28. By adopting this configuration, a lower profile can be achieved.

[0038] (Embodiment 4) A module in Embodiment 4 according to the present invention will be described with reference to Figure 13. A cross-sectional view of module 107 in this embodiment is shown in Figure 13.

[0039] Module 107 includes a shielding film 8 that covers the surface and sides of the sealing resin 6a that are far from the first substrate surface 51a. The metal foil 15 is covered by the shielding film 8. The other configurations are the same as those described for module 103 in Embodiment 3.

[0040] In this embodiment, the first region is the area of ​​the side surface of the sealing resin 6a, which serves as the first sealing resin surface 61, that is covered by the metal foil 15.

[0041] The metal foil 15 is bonded to the sealing resin 6a via a bonding material 16. In this embodiment, the shield film 8 is placed on the outside of the metal foil 15, and the shield film 8 covers the metal foil 15 in contact with it, so it is not necessary to place a conductive bonding material 26i as described in Embodiment 3. Electrical connection can be established between the shield film 8 and the metal foil 15 over the entire surface in contact with the metal foil 15.

[0042] In this embodiment as well, the same effects as those described in Embodiment 1 can be obtained. While obtaining the shielding effect of the shielding film 8 that covers the entire structure, the inclusion of the metal foil 15 further enables the realization of the required level of shielding performance in the necessary locations.

[0043] When the winding axis 31x of the inductor 31 is perpendicular to the first surface 51a of the substrate, a configuration like the module 108 shown in Figure 14 can be considered. The module 108 covers a part of the shield film 8 on the upper surface of the sealing resin 6a. In this case, the first surface 61 of the sealing resin is the upper surface of the sealing resin 6a. The region of the upper surface of the sealing resin 6a, which is the first surface 61 of the sealing resin, that is covered by the metal foil 15 is the first region.

[0044] Furthermore, in order to reduce the height, a configuration such as the module 109 shown in FIG. 15 can also be considered. In the module 109, the encapsulation resin 6a has a recess 27 on the surface farther from the first surface 51a of the substrate, and the metal foil 15 is disposed in the recess 27. By adopting this configuration, the height can be reduced. The shield film 8 may cover a portion of the inside of the recess 27 that is not covered by the metal foil 15.

[0045] In Embodiments 3 and 4, in a partial region of the shield film 8, the metal foil 15 is positioned so as to overlap the inside or the outside of the shield film 8, so that the total thickness of the conductors that can act as a shield member is locally increased. The metal foil 15 can be a sheet having a desired thickness attached thereto. Thereby, the shielding performance can be enhanced to a necessary degree in the partial region. In other regions, only the shield film 8 acts as a shield member, while in the partial region where the metal foil 15 is disposed, both the shield film 8 and the metal foil 15 can act as shield members. In the partial region, a configuration can be considered in which the total thickness of the conductors that can act as a shield member is more than twice that of an adjacent other region. A module having such a structure can also be expressed as follows.

[0046] The module includes a shield film 8 that covers the surface and side surfaces of the encapsulation resin 6a on the side farther from the first surface 51a of the substrate. The metal foil 15 overlaps a part of the shield film 8. In the region where the metal foil 15 and a part of the shield film 8 overlap, the sum of the thickness of the metal foil 15 and the thickness of the shield film 8 is more than twice the thickness of the shield film 8. By adopting this configuration, by disposing the metal foil so as to overlap a part of the shield film, the shielding performance of the necessary degree can be realized at the necessary locations.

[0047] Furthermore, multiple embodiments of the above-described embodiments may be used in appropriate combinations. The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, including all modifications within the meaning and scope of equivalences to the claims.

[0048] 6a, 6b Encapsulating resin, 7 Connecting conductor, 8 Shielding film, 12 Recess, 15 Metal foil, 16 Bonding material, 23, 24, 25 Electrodes, 26, 26i Conductive bonding material, 27 Recess (of the encapsulating resin), 28 Inclined portion (of the encapsulating resin), 31 Inductor, 31c Coil wiring, 31x Winding shaft, 32, 33, 34, 35 Components, 51 Substrate, 51a First surface of the substrate, 51b Second surface of the substrate, 61 First surface of the encapsulating resin, 61z First region, 91, 92 Arrows, 101, 102, 103, 104, 105, 106, 107, 108, 109 Module.

Claims

1. A module comprising: a substrate having a first substrate surface; an inductor having a winding shaft and mounted on the first substrate surface; and a sealing resin disposed to cover the inductor and the first substrate surface, wherein the sealing resin has a first sealing resin surface where the extensions of the winding shaft intersect, and a metal foil is disposed to cover a first region of the first sealing resin surface that includes the point where the extensions of the winding shaft intersect the first sealing resin surface and corresponds to the region obtained by projecting the inductor onto the first sealing resin surface, and the metal foil is grounded.

2. The module according to claim 1, wherein the first surface of the sealing resin is the surface of the sealing resin furthest from the first surface of the substrate, or is the side surface of the sealing resin.

3. The module according to claim 1 or 2, comprising a shielding film covering the surface and sides of the encapsulating resin that are furthest from the first surface of the substrate, wherein the metal foil is covered by the shielding film.

4. The module according to claim 1 or 2, comprising a shielding film that covers the surface and side of the sealing resin that is farther from the first surface of the substrate, wherein the metal foil covers a portion of the shielding film.

5. The module according to claim 1 or 2, comprising a shielding film that covers the surface and sides of the encapsulating resin that are furthest from the first surface of the substrate, wherein the metal foil overlaps with a portion of the shielding film, and in the region where the metal foil and a portion of the shielding film overlap, the sum of the thickness of the metal foil and the thickness of the shielding film is at least twice the thickness of the shielding film.

6. The module according to any one of claims 1 to 5, wherein the sealing resin has a recess on the side furthest from the first surface of the substrate, and the metal foil is disposed in the recess.

7. The module according to any one of claims 1 to 5, wherein the sealing resin has an inclined portion on at least a portion of the surface furthest from the first surface of the substrate, and the metal foil is arranged on the inclined portion.

8. The module according to any one of claims 1 to 7, wherein the first surface of the sealing resin includes an area not covered by the metal foil.

9. The module according to any one of claims 1 to 8, wherein the sealing resin has two or more surfaces on which the extensions of the winding shaft intersect, and the first surface of the sealing resin is the surface closest to the inductor among the two or more surfaces.

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