Wiring board

Abstract

A wiring board 1 is characterized by comprising: a substrate 10 having a first main surface 10a and a second main surface 10b facing each other in the thickness direction; a cavity 20 opened on the first main surface 10a of the substrate 10; a first electronic component 30 accommodated in the cavity 20; and a plurality of second electronic components 40A, 40B mounted on the first-main-surface 10a side of the substrate 10, the plurality of second electronic components 40A, 40B being arranged at positions that partially overlap the cavity 20, the wiring board 1 furthermore being characterized in that the second electronic components 40A, 40B are each electrically connected to the first electronic component 30, and, as seen from the thickness direction, the maximum dimension of an arrangement region where the plurality of second electronic components 40A, 40B are arranged is smaller than the total of maximum dimensions of the plurality of second electronic components 40A, 40B arranged within the arrangement region.

Description

wiring board

[0001] The present invention relates to a wiring board.

[0002] A known method for achieving a low profile and high density mounting of a module is to provide a cavity inside the substrate and accommodate components in the cavity.

[0003] For example, Patent Document 1 discloses a method of accommodating a die that connects semiconductor dies (hereinafter simply referred to as a die) such as ICs, which are a type of electronic component, in a cavity. A die that connects dies is also called a bridge die. In other words, Patent Document 1 discloses a structure in which a die, a bridge die, and another die are aligned in a straight line.

[0004] Similarly, Patent Document 2 discloses a wiring board in which a die, a bridge die, and a die are arranged in a straight line.

[0005] US Patent Application Publication No. 2022 / 0352075 JP 2021-153173 A

[0006] However, when a structure in which the die, bridge die, and die are aligned in a straight line is adopted, as in Patent Documents 1 and 2, the area in which the die and bridge die are arranged becomes longer, which requires the length of the substrate to be increased accordingly. This raises concerns that this will lead to an increase in the size of the substrate. Furthermore, if a long area of ​​the substrate is monopolized by the die, bridge die, and die, the layout of other electronic components will be restricted, which raises concerns that the degree of layout freedom will be reduced.

[0007] The present invention has been made to solve the above problems, and has an object to provide a wiring board that can suppress an increase in the size of the board and a decrease in the degree of freedom in layout.

[0008] The wiring board of the present invention comprises a substrate having a first main surface and a second main surface that are opposite to each other in a thickness direction, a cavity that opens to the first main surface of the substrate, a first electronic component housed in the cavity, and a plurality of second electronic components that are mounted on the first main surface side of the substrate and are arranged in a position where at least a portion of the second electronic components overlap with the cavity when viewed from the thickness direction, wherein the plurality of second electronic components are each electrically connected to the first electronic component, and when viewed from the thickness direction, the maximum dimension of the arrangement area in which the plurality of second electronic components are arranged is smaller than the sum of the maximum dimensions of the plurality of second electronic components arranged within the arrangement area.

[0009] According to the present invention, it is possible to provide a wiring board that can suppress an increase in the size of the board and a decrease in the degree of freedom in layout.

[0010] FIG. 1 is a cross-sectional view schematically showing an example of a wiring board of the present invention. FIG. 2 is a top view of the wiring board shown in FIG. 1. FIG. 3A is a simplified schematic diagram showing the positional relationship between cavities and second electronic components in the wiring board shown in FIG. 2. FIG. 3B is a schematic diagram showing an example in which the maximum dimension of the placement area is equal to the sum of the maximum dimensions of all second electronic components placed in the placement area. FIG. 4 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component constituting another example of a wiring board. FIG. 5 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring board. FIG. 6 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring board. FIG. 7 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring board. FIG. 8 is a top view schematically illustrating the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring board. FIG. 9 is a top view schematically illustrating the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring board. FIG. 10 is a cross-sectional view of the wiring board shown in FIG. 9 taken along line X-X. FIG. 11 is a top view schematically illustrating the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring board. FIG. 12 is a cross-sectional view of the wiring board shown in FIG. 11 taken along line XII-XII. FIG. 13 is a top view schematically illustrating the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring board. FIG. 14 is a cross-sectional view of the wiring board shown in FIG. 13 taken along line XIV-XIV. FIG. 15 is a top view schematically illustrating the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring board. FIG. 16 is a cross-sectional view of the wiring board shown in FIG. 15 taken along line XVI-XVI. FIG. 17 is a cross-sectional view schematically showing still another example of a wiring substrate.

[0011] The wiring board of the present invention will be described below. Note that the present invention is not limited to the following configurations and may be modified as appropriate within the scope of the present invention. In addition, a combination of multiple individual preferred configurations described below also constitutes the present invention.

[0012] The drawings shown below are schematic diagrams, and the dimensions, aspect ratio, and other scales may differ from those of the actual product. In the drawings, the same or equivalent parts will be designated by the same reference numerals. In addition, the same elements will be designated by the same reference numerals in each drawing, and duplicate explanations will be omitted.

[0013] In this specification, terms indicating the relationship between elements (e.g., "opposite," "orthogonal," etc.) and terms indicating the shape of elements not only mean the literal strict form, but also mean a range that is substantially equivalent, for example, a range that includes a difference of about a few percent.

[0014] The following embodiments are merely examples, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible. In the description of each embodiment, descriptions of matters common to the previously described embodiments will be omitted, and only differences will be described. In particular, similar effects resulting from similar configurations will not be mentioned in each embodiment.

[0015] [Wiring Board] The wiring board of the present invention comprises a substrate having a first main surface and a second main surface opposing each other in a thickness direction, a cavity opening to the first main surface of the substrate, a first electronic component accommodated in the cavity, and a plurality of second electronic components mounted on the first main surface side of the substrate and arranged in a position where at least a portion of the second electronic components overlaps with the cavity when viewed from the thickness direction, wherein the plurality of second electronic components are electrically connected to the first electronic components, and the maximum dimension of an arrangement area in which the plurality of second electronic components are arranged is smaller than the sum of the maximum dimensions of the plurality of second electronic components arranged in the arrangement area when viewed from the thickness direction.

[0016] Fig. 1 is a cross-sectional view schematically showing an example of a wiring board of the present invention, and Fig. 2 is a top view of the wiring board shown in Fig. 1. Line II shown in Fig. 2 corresponds to the cross section of Fig. 1.

[0017] The wiring board 1 shown in FIG. 1 includes a substrate 10 , a cavity 20 , a first electronic component 30 , and a second electronic component 40 .

[0018] The substrate 10 has a first main surface 10a and a second main surface 10b that face each other in the thickness direction (the direction indicated by the arrow Z in FIG. 1).

[0019] The substrate 10 may be a printed circuit board (also called a p-board) or a low-temperature co-fired ceramic (LTCC) substrate. Alternatively, the substrate 10 may be a resin multilayer substrate in which copper foil wiring is formed on a thermoplastic resin (e.g., polyetheretherketone (PEEK), polyimide (PI), or liquid crystal polymer (LCP)). The low-temperature co-fired ceramic (LTCC) substrate is a substrate formed by laminating insulating layers made of low-temperature co-fired ceramic (LTCC) material and having wiring (internal wiring) inside.

[0020] Low-temperature co-fired ceramic materials are ceramic materials that can be fired at temperatures of 1000°C or less and can be co-fired with Au, Ag, Cu, etc., which have low resistivity. Specific examples of low-temperature co-fired ceramic materials include glass composite low-temperature co-fired ceramic materials obtained by mixing ceramic powders such as alumina, zirconia, magnesia, and forsterite with borosilicate glass; ZnO-MgO-Al ２ O ３ -SiO ２ Glass-ceramic low-temperature fired ceramic material using BaO-Al ２ O ３ -SiO ２ Ceramic powder and Al ２ O ３ -CaO-SiO ２ -MgO-B ２ O ３ Examples of suitable ceramic materials include non-glass-based low-temperature fired ceramic materials using ceramic powders.

[0021] The internal wiring may be made of Cu, Ag, Au or the like.

[0022] The cavity 20 shown in FIG. 1 is a bottomless cavity that opens to the first main surface 10 a and the second main surface 10 b of the substrate 10 .

[0023] The cavity provided in the wiring board of the present invention may be a bottomless cavity or a bottomed cavity. A bottomless cavity is a cavity that penetrates from the first main surface 10a to the second main surface 10b of the substrate 10. When the cavity 20 is a bottomless cavity, the bottom surface of the first electronic component 30 may be exposed on the second main surface 10b of the substrate 10.

[0024] The bottomed cavity is a non-through cavity that opens to the first main surface 10a of the substrate 10 and has a bottom surface on the second main surface 10b side.

[0025] A metal layer may be provided so as to cover the side surface of the cavity 20. The metal layer may be a part of wiring provided in the substrate that is exposed on the inner surface of the cavity 20. By connecting this metal layer to a GND potential, the metal layer functions as a shield.

[0026] The first electronic component 30 is housed in the cavity 20. The volume of the cavity 20 is larger than the volume of the first electronic component 30. No external electrodes are provided on the side or bottom surfaces of the first electronic component 30. Therefore, the first electronic component 30 is not directly connected to the substrate 10.

[0027] Examples of the first electronic component 30 include a semiconductor chip (die), passive components such as a capacitor or a coil, and a filter.

[0028] Two or more first electronic components 30 may be housed in one cavity 20. The types of the multiple first electronic components 30 housed in the same cavity 20 may be the same or different.

[0029] A plurality of second electronic components 40 are mounted on the first main surface 10a of the substrate 10. The second electronic components 40 are electronic components that are mounted on the first main surface 10a of the substrate 10 and are arranged at positions where at least a portion of the second electronic components 40 overlaps with the cavity 20 when viewed from the thickness direction Z. Each of the plurality of second electronic components 40 is electrically connected to the first electronic component 30.

[0030] By connecting the first electronic component 30 to the second electronic component 40, the position of the first electronic component 30 within the cavity 20 is fixed, and electrical connection with the substrate 10 is ensured. Note that the connection between the first electronic component 30 and the second electronic component 40 may be such that the electrodes of the respective electronic components are directly connected via solder, or such that the electrodes of one of the electronic components have solder bumps and the electrodes are connected via the solder bumps.

[0031] Note that "mounting" refers to the state in which an electronic component is fixed to a substrate without any other electronic components in between, thereby enabling the electronic component to perform its function. Therefore, an electronic component fixed in a cavity 20 via a second electronic component 40 mounted on the first main surface 10a of the substrate 10, such as the first electronic component 30 shown in Figures 1 and 2, is not said to be mounted on the substrate 10.

[0032] In other words, among the electronic components mounted on the first main surface 10a of the substrate 10, the second electronic component 40 is the one that is positioned so that at least a portion of it overlaps with the cavity 20 when viewed from the thickness direction Z and is electrically connected to the first electronic component 30.

[0033] Examples of the second electronic component 40 include a semiconductor chip (die), passive components such as a capacitor or a coil, and a filter.

[0034] When the first electronic component 30 (die) connects multiple second electronic components 40 (die) mounted on the first main surface 10a of the substrate 10, the first electronic component 30 is also called a bridge die.

[0035] Examples of combinations of the first electronic component 30 and the second electronic component 40 include a case where both the second electronic component 40 are dies and the first electronic component 30 is a passive element such as a capacitor, and a case where both the first electronic component 30 and the second electronic component 40 are dies. Examples of dies include integrated circuits (ICs) such as power amplifiers (PAs) and low-noise amplifiers (LNAs). Examples of bridge dies include high-density silicon capacitors (DTCs: also known as deep trench capacitors) manufactured using semiconductor MOS processes. A DTC is also a type of capacitor. The second electronic component 40 combined with a DTC may be a chiplet (a portion of a large-area die divided into functional sections).

[0036] Because the DTC allows all electrodes to be drawn out from one surface, it is possible to ensure connection to multiple second electronic components 40 on the same surface. This makes it easy to design the connection between the first electronic component 30 and the second electronic component 40. Furthermore, even if the number of second electronic components 40 connected to the first electronic component 30 increases, it is easy to accommodate an increase in the number of second electronic components 40 because complex electrode routing is not required.

[0037] If both the first electronic component 30 and the second electronic component 40 are ICs, a coil, a capacitor, or the like may be further mounted on the substrate as a third electronic component 50 as an element for an impedance matching circuit corresponding to each IC.

[0038] That is, in addition to the first electronic component 30 and the second electronic component 40, a plurality of third electronic components 50 may be mounted on the first main surface 10a of the substrate 10. The third electronic components 50 refer to electronic components other than the first electronic component 30 and the second electronic component 40, among the electronic components mounted on the substrate 10. The third electronic components 50 may be mounted on the second main surface 10b of the substrate 10.

[0039] The third electronic component 50 may be mounted on the first main surface 10a of the substrate 10, or may be mounted on the second main surface 10b of the substrate 10. When the third electronic component 50 is mounted on the second main surface 10b of the substrate 10, the substrate 10 is also called a double-sided substrate.

[0040] The second electronic component 40 mounted on the first main surface 10a of the substrate 10 may be sealed with a sealing resin 61. The sealing resin 61 may cover the entire first main surface 10a of the substrate 10 and form a resin layer 60.

[0041] A part of the sealing resin 61 may be present inside the cavity 20. The type of resin constituting the sealing resin 61 is not particularly limited, but examples thereof include epoxy resin. In addition to the sealing resin 61, the resin layer 60 may contain an additive such as a filler.

[0042] The sealing resin 61 covering the first main surface 10 a of the substrate 10 is also referred to as the first sealing resin 61 to distinguish it from the sealing resin covering the second main surface 10 b described below. The resin layer 60 formed by the first sealing resin 61 is also referred to as the first resin layer 60.

[0043] A shielding film 70 may be formed on the surfaces (top and side surfaces) of the resin layer 60. When the shielding film 70 is formed on the top surface of the resin layer 60, a through conductor 80 may be provided in the resin layer 60, penetrating the resin layer 60 in the thickness direction Z and connecting the first main surface 10a of the substrate 10 and the shielding film 70. The through conductor 80 allows the internal wiring of the substrate 10 to be connected to the shielding film 70, so that, for example, the GND wiring inside the substrate 10 can be connected to the shielding film 70.

[0044] Shielding films 70 may also be formed on the side surfaces of the substrate 10. In the substrate 10 shown in Figures 1 and 2, the shielding films 70 are formed so as to cover the first side surface 10c, the second side surface 10d, the third side surface 10e, and the fourth side surface 10f. The first side surface 10c and the second side surface 10d of the substrate 10 are side surfaces that face each other in a length direction (direction indicated by arrow X in Figure 1) that faces the thickness direction Z, and the third side surface 10e and the fourth side surface 10f are side surfaces that face each other in a width direction (direction indicated by arrow Y in Figure 2) that is perpendicular to the thickness direction Z and the length direction X.

[0045] In the wiring board of the present invention, the maximum dimension of the placement area in which the plurality of second electronic components are arranged, when viewed from the thickness direction, is smaller than the sum of the maximum dimensions of all the second electronic components arranged in that placement area. In other words, the placement of the plurality of second electronic components is not particularly limited as long as the maximum dimension of the placement area in which the plurality of second electronic components are arranged is smaller than the sum of the maximum dimensions of all the second electronic components arranged in that placement area. This is explained using FIG. 3, which is a simplified version of the wiring board 1 shown in FIG. 2.

[0046] FIG. 3A is a simplified schematic diagram showing the positional relationship between the cavity and the second electronic component in the wiring board shown in FIG. 2. FIG.

[0047] 3A , when the second electronic components 40A and 40B are arranged on the wiring board 1, the longitudinal directions of the two second electronic components 40A and 40B both extend along the width direction Y and are substantially parallel to each other. The two second electronic components 40A and 40B are also arranged side by side along the short side direction.

[0048] The placement region M1 is defined as a rectangle with the minimum area in which all the second electronic components 40 (in this case, the second electronic components 40A and 40B) can be placed. In Fig. 3, the region indicated by the dashed line is the placement region M1.

[0049] The length of the second electronic components 40A and 40B in the longitudinal direction of the portion where the second electronic components 40A and 40B are aligned with each other in the lateral direction, i.e., the portion where the second electronic components 40A and 40B are overlapped in the lateral direction, is the maximum dimension L of the second electronic component 40A. Ａ and the maximum dimension L of the second electronic component 40B Ｂ Therefore, the maximum size of the placement area M1 (shown by the double-headed arrow L in FIG. 3) is Ｍ１ The length indicated by is the maximum dimension L of the second electronic component 40A. Ａ and the maximum dimension L of the second electronic component 40B Ｂ The sum of (L Ａ +L Ｂ ) to find the length of the overlapping part (L Ａ or L Ｂ ) is the length excluding the maximum dimension L Ｍ１is the maximum dimension L of the second electronic component 40A. Ａ or the maximum dimension L of the second electronic component 40B Ｂ Therefore, the maximum dimension L of the arrangement region M1 in which the plurality of second electronic components 40 are arranged is equal to Ｍ１ (L Ａ or L Ｂ ) is the sum of the maximum dimensions of the second electronic components 40 placed in the placement region M1 (L Ａ +L Ｂ ) is smaller than

[0050] This means that the area in which the second electronic components are arranged does not extend long in one direction. This will be explained with reference to Fig. 3B. Fig. 3B is a diagram schematically showing an example in which the maximum dimension of the arrangement area is equal to the sum of the maximum dimensions of all the second electronic components arranged in the arrangement area. As shown in Fig. 3B, when a plurality of second electronic components 40A, 40B are arranged in a straight line along their longitudinal direction with no gaps between them, the maximum dimension L of the arrangement area M0 in which all the second electronic components 40A, 40B are arranged is Ｍ０ is the sum of the maximum dimensions of all the second electronic components 40A, 40B placed in the placement area M0 (L Ａ +L Ｂ In such an arrangement, the area required for arranging the second electronic component becomes long, which may lead to an increase in the size of the board and a decrease in the degree of freedom in layout.

[0051] In contrast, if the second electronic components are arranged so that the maximum dimension of the placement area is smaller than the sum of the maximum dimensions of all second electronic components placed in the placement area, the maximum length of the area for placing the second electronic components can be shortened, thereby preventing the board from becoming larger and reducing the freedom of layout.

[0052] When viewed from the thickness direction, the cavity may be exposed on one, two, or three sides of the outer shape of the substrate. When a cavity is provided in a substrate, an area is created around the cavity where internal wiring or electronic components cannot be installed, taking into account manufacturing errors, etc. This area is called a dead area (also called a margin area). If the cavity is exposed on one, two, or three sides of the outer shape of the substrate, the dead area can be reduced. In addition, since a shielding film can be used on the exposed surface of the substrate, the area in which the compartment shield is formed can be reduced.

[0053] The greater the number of exposed sides of the cavity, the greater the effect of reducing the dead area and the area where the compartment shield is formed.

[0054] The sides of the external shape of the board are determined by the positional relationship between the side surfaces of the board constituting the wiring board, the side surfaces of the resin layer, and the electronic components mounted on the board. Specifically, if the board is exposed on the side surface of the wiring board excluding the shielding film, the sides formed by the board are considered to be the sides of the external shape of the board. Also, if there is a notch on the side surface of the board, the side surface of the board as if the notch did not exist is considered to be the side of the external shape of the board.

[0055] On the other hand, when the resin layer, not the substrate, is exposed on the side surface of the wiring board excluding the shielding film (i.e., when the side surface of the resin layer protrudes outward from the side surface of the substrate), the side surface of the resin layer is considered to be the side of the outer shape of the board. Therefore, in wiring board 1D shown in Figure 7 (described later), the sides of the outer shape of board 10 are 10c, 10d, 10e, and 10f, and it can be said that cavity 20 is exposed on three sides (10c, 10e, and 10f) of the outer shape of board 10.

[0056] 4 to 8, another example of the arrangement of the second electronic components is shown.

[0057] FIG. 4 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component that constitute another example of a wiring substrate.

[0058] In the wiring board 1A shown in FIG. 4, the cavity 20 is exposed on one side (10c) of the outer shape of the substrate 10.

[0059] When viewed from the thickness direction Z, the longitudinal directions of the second electronic components 40A, 40B are all substantially parallel, and some of the second electronic components are arranged side by side along the lateral direction.

[0060] Maximum dimension L of placement area M2 Ｍ２ is the maximum dimension L of the second electronic component 40A. Ａ and the maximum dimension L of the second electronic component 40B. Ｂ From the sum of these, the length L of the portion where the second electronic component 40A and the second electronic component 40B are aligned in the short direction, i.e., the overlapping portion, is obtained. ＯＲ Therefore, the maximum dimension L of the placement area M2 is Ｍ２ (L Ａ +L Ｂ -L ＯＲ ) is the maximum dimension L of the second electronic component 40A. Ａ and the maximum dimension L of the second electronic component 40B. Ｂ The sum of (L Ａ +L Ｂ ) is smaller than

[0061] FIG. 5 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component that constitute yet another example of a wiring substrate.

[0062] In the wiring board 1B shown in FIG. 5, the cavity 20 is exposed on two sides (10c, 10f) of the outer shape of the substrate 10.

[0063] The arrangement of the second electronic components 40A and 40B is the same as that of the wiring board 1 shown in FIGS. Ｍ３ is the maximum dimension L of the second electronic component 40A. Ａ and the maximum dimension L of the second electronic component 40B. Ｂ The sum of (L Ａ +L Ｂ ) is smaller than

[0064] FIG. 6 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component that constitute yet another example of a wiring substrate.

[0065] In the wiring board 1C shown in FIG. 6, the cavity 20 is exposed on two sides (10c, 10f) of the outer shape of the substrate 10.

[0066] When viewed from the thickness direction Z, the longitudinal directions of the second electronic components 40A, 40B are perpendicular to each other and are not parallel to each other.

[0067] Maximum dimension L of placement area M4 Ｍ４ is the maximum dimension L of the second electronic component 40A. Ａ and the dimension S in the short side direction of the second electronic component 40B. Ｂ and the distance between the second electronic component 40A and the second electronic component 40B (the length indicated by the double-headed arrow G in FIG. 6).

[0068] The dimension S in the short side direction of the second electronic component 40B Ｂ is the longitudinal dimension (maximum dimension) L of the second electronic component 40B. Ｂ smaller than dimension S Ｂ Even if the distance G between the second electronic components 40A and 40B is added to the above, the maximum dimension L of the second electronic component 40B is Ｂ Therefore, the maximum dimension L of the placement area M4 is Ｍ４ (S Ｂ +G+L Ａ ) is the maximum dimension L of the second electronic component 40A. Ａ and the maximum dimension L of the second electronic component 40B. Ｂ The sum of (L Ａ +L Ｂ ) is smaller than

[0069] FIG. 7 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component that constitute yet another example of a wiring substrate.

[0070] In the wiring board 1D shown in FIG. 7, the cavity 20 is exposed on three sides (10c, 10e, 10f) of the outer shape of the substrate 10.

[0071] When viewed from the thickness direction Z, the longitudinal directions of the second electronic components 40A, 40B are all substantially parallel, and some of the second electronic components 40 are arranged side by side along the lateral direction.

[0072] Maximum dimension L of placement area M5 Ｍ５ is the dimension S in the short side direction of the second electronic component 40AＡ and the dimension S in the short side direction of the second electronic component 40B. Ｂ and the distance G between the second electronic component 40A and the second electronic component 40B in the width direction Y. Ａ is the maximum dimension L of the second electronic component 40A Ａ and the dimension S in the short side direction of the second electronic component 40B is smaller than Ｂ is the maximum dimension L of the second electronic component 40B Ｂ On the other hand, the distance G between the second electronic component 40A and the second electronic component 40B in the width direction Y is small. Therefore, the maximum dimension L of the placement region M5 is Ｍ５ (S Ｂ +G+S Ａ ) is the maximum dimension L of the second electronic component 40A. Ａ and the maximum dimension L of the second electronic component 40B. Ｂ The sum of (L Ａ +L Ｂ ) is smaller than

[0073] FIG. 8 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component that constitute yet another example of a wiring substrate.

[0074] 8, the cavity 20 is exposed on one side (10f) of the outer shape of the substrate 10. Three second electronic components 40A, 40B, and 40C are mounted on the first main surface 10a of the substrate 10 at positions overlapping the cavity 20.

[0075] When viewed from the thickness direction Z, the longitudinal directions of the multiple second electronic components 40A, 40B, and 40C are all approximately parallel, and the second electronic components 40A and portions of the second electronic components 40C, and the second electronic components 40B and portions of the second electronic components 40C are arranged so as to be aligned along the short side direction.

[0076] Therefore, the maximum dimension L of the placement area M6 Ｍ６ is the maximum dimension L of the second electronic component 40A. Ａ and the maximum dimension L of the second electronic component 40B. Ｂand the distance between the second electronic component 40A and the second electronic component 40B (the length indicated by the double-headed arrow G in FIG. 8). The length of the distance G between the second electronic component 40A and the second electronic component 40B is the maximum dimension L of the second electronic component 40C. Ｃ Since it is small compared with the maximum dimension L of the placement area M6 Ｍ６ (L Ａ +G+L Ｂ ) is the maximum dimension L of the second electronic component 40A. Ａ and the maximum dimension L of the second electronic component 40B. Ｂ and the maximum dimension L of the second electronic component 40C. Ｃ The sum of (L Ａ +L Ｂ +L Ｃ ) is smaller than

[0077] In the wiring board of the present invention, the second electronic component may overlap in the thickness direction with a cavity different from the cavity in which the first electronic component is housed.

[0078] A cavity other than the cavity that accommodates the first electronic component provided on the substrate is also referred to as a second cavity. In this case, the cavity that accommodates the first electronic component is also referred to as a first cavity.

[0079] That is, the second electronic component may be disposed at a position where a portion of the second electronic component overlaps with the second cavity when viewed in the thickness direction.

[0080] Since the second electronic component is mounted on the first main surface 10a of the substrate 10, the second cavity is a bottomed cavity.

[0081] The second electronic component overlapping the second cavity may be partially or completely present within the second cavity.

[0082] An example of a wiring board in which the second electronic component is disposed at a position overlapping the second bottomed cavity will be described with reference to FIGS. 9 and 10. FIG.

[0083] Fig. 9 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring substrate, Fig. 10 is a cross-sectional view of the wiring substrate shown in Fig. 9 taken along line XX.

[0084] In the wiring substrate 2 shown in FIGS. 9 and 10, the substrate 10 has a first cavity 20 which is a bottomless cavity and a second cavity 21 which is a bottomed cavity.

[0085] The first cavity 20 accommodates a first electronic component 30 .

[0086] The second electronic components 40A, 40B are each arranged at a position overlapping both the first cavity 20 and the second cavity 21 when viewed from the thickness direction. Specifically, a portion of each of the second electronic components 40A, 40B is arranged at a position overlapping with the first cavity 20 when viewed from the thickness direction, and another portion is arranged at a position overlapping with the second cavity 21 when viewed from the thickness direction.

[0087] The second electronic components 40A, 40B are electrically connected to the first electronic components 30 at positions that overlap the first cavity 20 when viewed in the thickness direction.

[0088] The second electronic components 40A, 40B are connected to the substrate 10 at positions that overlap the second cavities 21 when viewed in the thickness direction. In other words, the second electronic components 40A, 40B are connected to the substrate 10 at the bottom surfaces of the second cavities 21.

[0089] 9 and 10, since the second cavity 21 opens to the first main surface 10a of the substrate 10, the second electronic components 40A, 40B mounted in the second cavity 21 can be said to be mounted on the first main surface 10a of the substrate 10.

[0090] A third electronic component 51 is provided on the second main surface 10b of the substrate 10. The third electronic component 51 mounted on the second main surface 10b of the substrate 10 may be covered with a sealing resin 66. A layer made of the sealing resin 66 that covers the second main surface 10b of the substrate 10 is also referred to as a resin layer 65. The resin layer 65 that covers the second main surface 10b of the substrate 10 is also referred to as a second resin layer 65 to distinguish it from the resin layer 60 that covers the first main surface 10a of the substrate 10. The sealing resin 66 that constitutes the second resin layer 65 is also referred to as a second sealing resin 66 to distinguish it from the first sealing resin 61 that constitutes the first resin layer 60.

[0091] A through conductor 81 may be provided so as to penetrate the resin layer 65 in the thickness direction Z. The through conductor 81 is exposed on the surface of the second resin layer 65 (the surface farther from the second main surface 10b), extends the second main surface 10b of the substrate 10 to the surface of the second resin layer 65, and functions as a terminal for mounting the wiring board 2.

[0092] In the wiring board of the present invention, the size of the connection conductor between the second electronic component and the substrate may vary for each second electronic component, or may vary depending on the distance from the substrate. Examples of the connection conductor between the second electronic component and the substrate include solder bumps and metal pins. Note that the size of the connection conductor here refers to the volume of the connection conductor.

[0093] Fig. 11 is a top view schematically illustrating the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring substrate, Fig. 12 is a cross-sectional view of the wiring substrate shown in Fig. 11 taken along line XII-XII.

[0094] 11 and 12 , the substrate 10 constituting the wiring board 3 is provided with a first cavity 20, which is a bottomless cavity, and a second cavity 21, which is a bottomed cavity. Second electronic components 40A and 40B are mounted on the first main surface 10a of the substrate 10. When viewed in the thickness direction, the second electronic component 40B is disposed in a position overlapping the second cavity 21, but the second electronic component 40A does not overlap the second cavity 21. Focusing on the connection conductors between the second electronic components 40A and 40B and the substrate 10, the size of the bump 92, which is a connection conductor connecting the substrate 10 and the second electronic component 40B, is larger than the size of the bump 91, which is a connection conductor connecting the substrate 10 and the second electronic component 40A.

[0095] Increasing the cross-sectional area (area as viewed from the thickness direction Z) of the connecting conductor connecting the substrate and the second electronic component to accommodate large currents or improve connectivity generally requires increasing the size of the connecting conductor, which generally results in an increase in the thickness of the connecting conductor. In other words, increasing the size of the connecting conductor between the substrate and the second electronic component increases the height of the second electronic component by the amount of the increased thickness of the connecting conductor. This can lead to problems such as the second electronic component becoming unlevel with respect to the substrate or being misaligned in height with other second electronic components. In contrast, by placing the larger connecting conductor (bump 92) in the second cavity 21, as in the wiring substrate 2 shown in FIGS. 11 and 12 , the size of the connecting conductor can be increased while maintaining the second electronic component 40B level with respect to the substrate 10 and at the same height as the second electronic component 40A.

[0096] Fig. 13 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring substrate, Fig. 14 is a cross-sectional view of the wiring substrate shown in Fig. 13 taken along line XIV-XIV.

[0097] 13 and 14 , a substrate 10 constituting a wiring board 4 is provided with a first cavity 20, which is a bottomless cavity, and a second cavity 21, which is a bottomed cavity. Second electronic components 40A and 40B are mounted on a first main surface 10a of the substrate 10. When viewed in the thickness direction, the second electronic component 40B is disposed in a position overlapping with the second cavity 21, but the second electronic component 40A does not overlap with the second cavity 21. The arrangement of the second electronic components 40A and 40B in the wiring board 4 is the same as that of the wiring board 3 shown in FIGS. 11 and 12 .

[0098] Focusing on the connection conductors between the second electronic components 40A, 40B and the substrate 10, the size (height) of the metal pillar 93 connected to the second electronic component 40B is larger than the size (height) of the bump 91 connected to the second electronic component 40A.

[0099] In addition to the cavity for accommodating the first electronic component, the substrate may be provided with two or more cavities of different depths. In this case, the second cavity, the third cavity, and so on are defined in order of shallowest depth. Also, when viewed from the thickness direction Z, different second electronic components may be overlapped in the second cavity and the third cavity, respectively.

[0100] Since the second electronic component is mounted on the first main surface of the substrate, the third cavity is also a bottomed cavity like the second cavity.

[0101] By accommodating a plurality of second electronic components so that they overlap in cavities of different depths, it is possible to change the size of the bumps without changing the mounting height of the second electronic components.

[0102] Fig. 15 is a top view schematically showing the arrangement of a substrate, a cavity, and a second electronic component constituting yet another example of a wiring substrate, Fig. 16 is a cross-sectional view of the wiring substrate shown in Fig. 15 taken along line XVI-XVI.

[0103] The substrate 10 constituting the wiring board 5 has a first cavity 20, which is a bottomless cavity, and a second cavity 21 and a third cavity 22, which are bottomed cavities. Second electronic components 40A and 40B are mounted on the first main surface 10a of the substrate 10. When viewed in the thickness direction, the second electronic component 40A is disposed in a position overlapping the second cavity 21, and the second electronic component 40B is disposed in a position overlapping the third cavity 22. As shown in FIG. 15 , the second cavity 21 and the third cavity 22 are adjacent to each other when viewed in the thickness direction Z, but have different depths as shown in FIG. 16 .

[0104] The arrangement of the second electronic components 40A and 40B on the wiring board 5 is the same as that on the wiring board 1D shown in FIG.

[0105] The connection conductor between the second electronic component 40A overlapping the second cavity 21 and the substrate 10 is a bump 91, and the connection conductor between the second electronic component 40B overlapping the third cavity and the substrate 10 is a metal pillar 93. Note that the metal pillar 93 is typically a copper pillar (Cu pillar). As with the wiring substrate 5, the sizes of the connection conductors can be adjusted by arranging the second electronic components 40A and 40B at positions that overlap cavities of different depths.

[0106] The wiring board of the present invention may have a second substrate provided on the second main surface side of the substrate, spaced apart from the second main surface. In this case, the substrate is also referred to as a first substrate to distinguish it from the second substrate. An example of a wiring board having a second substrate will be described with reference to FIG.

[0107] FIG. 17 is a cross-sectional view schematically showing still another example of a wiring substrate.

[0108] 17 , a second substrate 15 is further provided on the second main surface 10b side of the substrate (first substrate) 10. The second substrate 15 has a first main surface 15a and a second main surface 15b that face each other in the thickness direction Z, and is spaced apart from the first substrate 10. A third electronic component 50 may be mounted on the second substrate 15.

[0109] The first substrate 10 and the second substrate 15 may be electrically connected by a through conductor 81 .

[0110] A sealing resin 66 may be filled between the first substrate 10 and the second substrate 15. A resin layer 65 made of this sealing resin 66 is a resin layer that covers the second main surface 10b of the first substrate 10, and is therefore the second resin layer 65.

[0111] This specification describes the following:

[0112] The present disclosure (1) is a wiring board comprising: a substrate having a first main surface and a second main surface opposing each other in a thickness direction; a cavity opening to the first main surface of the substrate; a first electronic component housed in the cavity; and a plurality of second electronic components mounted on the first main surface side of the substrate and arranged in a position where at least a portion of the second electronic components overlaps with the cavity when viewed from the thickness direction, wherein the second electronic components are each electrically connected to the first electronic component; and wherein, when viewed from the thickness direction, the maximum dimension of a placement area in which the second electronic components are arranged is smaller than the sum of the maximum dimensions of the second electronic components arranged within the placement area.

[0113] The present disclosure (2) is a wiring board according to the present disclosure (1), in which the cavity is exposed to one, two or three sides of the outer shape of the board when viewed in the thickness direction.

[0114] The present disclosure (3) is the wiring board according to the present disclosure (1) or (2), in which the shapes of the second electronic components when viewed from the thickness direction are all rectangular shapes having a longitudinal direction and a lateral direction, the longitudinal directions of the plurality of second electronic components are all approximately parallel when viewed from the thickness direction, and at least some of the plurality of second electronic components are arranged so as to be aligned with each other along the lateral direction.

[0115] The present disclosure (4) is the wiring board according to the present disclosure (1) or (2), in which the shapes of the second electronic components when viewed in the thickness direction are all rectangular shapes having a longitudinal direction and a lateral direction, and the longitudinal direction of at least one of the second electronic components is not parallel to the longitudinal directions of the other second electronic components.

[0116] The present disclosure (5) is a wiring board that is an arbitrary combination of any of the present disclosures (1) to (4), in which, among the plurality of second electronic components, the size of a connection conductor connecting one of the second electronic components to the substrate is larger than the size of a connection conductor connecting the other of the second electronic components to the substrate.

[0117] The present disclosure (6) is a wiring board in any combination with any of the present disclosures (1) to (5), wherein the substrate has a second cavity that opens to the first main surface and has a bottom surface on the second main surface side, a part of the second electronic component is arranged in a position that overlaps with the second cavity when viewed from the thickness direction, and the second electronic component is connected to the substrate at the bottom surface of the second cavity.

[0118] The present disclosure (7) is a wiring board in any combination with any of the present disclosures (1) to (6), in which a second substrate spaced apart from the second main surface is provided on the second main surface side of the substrate.

[0119] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C, 1D, 1E, 2, 3, 4, 5, 6 Wiring board 10 Substrate (first substrate) 10a First main surface 10b Second main surface 10c First side surface 10d Second side surface 10e Third side surface 10f Fourth side surface 15 Substrate (second substrate) 15a First main surface 15b Second main surface 20 Cavity (first cavity) 21 Second cavity 22 Third cavity 30 First electronic component 40, 40A, 40B, 40C Second electronic component 50, 51 Third electronic component 60 Resin layer (first resin layer) 61 Sealing resin (first sealing resin) 65 Resin layer (second resin layer) 66 Sealing resin (second sealing resin) 70 Shielding layer 80, 81 Through conductor 91, 92 Bump (connecting conductor) 93 Metal pillar (connecting conductor) M0, M1, M2, M3, M4, M5, M6 Arrangement area LＭ０ , L Ｍ１ , L Ｍ２ , L Ｍ３ , L Ｍ４ , L Ｍ５ , L Ｍ６ Maximum size of placement area L Ａ , L Ｂ , L Ｃ Maximum dimension of second electronic component S Ａ , S Ｂ Short side dimension L of the second electronic component ＯＲ Length of overlapping part G Distance between second electronic components

Claims

1. A wiring board comprising: a substrate having a first main surface and a second main surface opposing each other in a thickness direction; a cavity opening to the first main surface of the substrate; a first electronic component housed in the cavity; and a plurality of second electronic components mounted on the first main surface side of the substrate and arranged in a position where at least a portion of the second electronic components overlaps with the cavity when viewed in the thickness direction, wherein the second electronic components are each electrically connected to the first electronic component; and wherein, when viewed in the thickness direction, the maximum dimension of a placement area in which the second electronic components are arranged is smaller than the sum of the maximum dimensions of the second electronic components arranged in the placement area.

2. The wiring board according to claim 1, wherein the cavity is exposed on one, two or three sides of the outer shape of the board when viewed in the thickness direction.

3. The wiring board according to claim 1 or 2, wherein the shape of each of the second electronic components when viewed in the thickness direction is a rectangle having a longitudinal direction and a lateral direction, the longitudinal directions of the plurality of second electronic components are all approximately parallel when viewed in the thickness direction, and at least some of the plurality of second electronic components are arranged so as to be aligned with each other along the lateral direction.

4. The wiring board according to claim 1 or 2, wherein the shape of each of the second electronic components when viewed in the thickness direction is a rectangle having a longitudinal direction and a lateral direction, and the longitudinal direction of at least one of the second electronic components is not parallel to the longitudinal directions of the other second electronic components.

5. A wiring board according to any one of claims 1 to 4, wherein, among the plurality of second electronic components, the size of the connection conductor connecting one of the second electronic components to the substrate is larger than the size of the connection conductor connecting the other of the second electronic components to the substrate.

6. The wiring board according to any one of claims 1 to 5, wherein the substrate has a second cavity that opens to the first main surface and has a bottom surface on the second main surface side, when viewed from the thickness direction, a part of the second electronic component is arranged in a position that overlaps with the second cavity, and the second electronic component is connected to the substrate at the bottom surface of the second cavity.

7. The wiring board according to any one of claims 1 to 6, wherein a second substrate is provided on the second main surface side of the substrate, spaced apart from the second main surface.

Images