Substrate

Abstract

The present invention suppresses generation of voids in solder on a pad, and improves heat dissipation of an electronic component connected to the pad. This substrate is provided with: a plate-shaped base part; a pad that is provided on one main surface of the base and contains a metal; and a solder resist provided on a portion of the surface of the pad. A plurality of holes penetrating the pad and the base in the thickness direction of the base are formed at positions on the pad different from the positions where the solder resist is provided. In a plan view in the thickness direction of the base, the solder resist extends between the plurality of holes without overlapping the plurality of holes, and is in contact with the edge of the pad.

Description

Technical Field

[0001] The present disclosure relates to a substrate having pads capable of dissipating heat generated in electronic components. Background Art

[0002] Conventionally, as such a substrate, for example, a printed wiring board described in Patent Document 1 is known. The printed wiring board has pads divided into a plurality of divided pads by a solder resist. The pads can be connected to electronic components via solder. Heat generated in the electronic components is dissipated through the solder and the pads.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2012-099682 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In the printed wiring board of Patent Document 1, there is room for improvement from the viewpoints of suppressing voids in the solder on the pads and improving the heat dissipation of the electronic components connected to the pads.

[0008] Therefore, an object of the present disclosure is to solve the above problems, suppress voids in the solder on the pads, and improve the heat dissipation of the electronic components connected to the pads.

[0009] Means for Solving the Problems

[0010] The substrate of the present disclosure includes: a plate-shaped base; pads provided on one main surface of the base and containing a metal; and a solder resist provided on a part of the surface of the pads. A plurality of holes penetrating the pads and the base in the thickness direction of the base are formed at positions different from the position where the solder resist is provided on the pads. The solder resist is configured to extend between the plurality of holes without overlapping the plurality of holes and to abut on the edges of the pads when viewed from above in the thickness direction of the base.

[0011] Advantages of the Invention

[0012] According to the present disclosure, it is possible to suppress voids in the solder on the pads and improve the heat dissipation of the electronic components connected to the pads. Brief Description of the Drawings

[0013] Figure 1 is a top view of the substrate according to an embodiment of the present disclosure.

[0014] Figure 2 is along Figure 1Cross-sectional view taken along line II-II.

[0015] Figure 3 is a cross-sectional view corresponding to the module showing an embodiment of the present disclosure and Figure 2 corresponding thereto.

[0016] Figure 4 is Figure 1 a flowchart showing the manufacturing process of the substrate and the mounting process of mounting an electronic component on the substrate.

[0017] Figure 5 is Figure 1 an enlarged top view showing a first modification example of a pad in the substrate.

[0018] Figure 6 is a top view of a substrate according to an embodiment of the present disclosure and is a view showing a second modification example of a pad.

[0019] Figure 7 is Figure 6 a top view showing a third modification example of a pad in the substrate.

[0020] Figure 8 is Figure 6 a top view showing a fourth modification example of a pad in the substrate.

[0021] Figure 9 is Figure 6 a top view showing a fifth modification example of a pad in the substrate.

[0022] Figure 10 is Figure 6 a top view showing a sixth modification example of a pad in the substrate. Detailed Description

[0023] <Insight underlying the present disclosure>

[0024] The inventor of the present invention conducted in-depth research in order to suppress the generation of voids in the solder on the pad and improve the heat dissipation of the electronic component connected to the pad, and as a result, obtained the following insights.

[0025] In the printed wiring board described in Patent Document 1, a solder resist is disposed on a part of the pads on one main surface. By this solder resist, the pads are divided into a plurality of divided pads. In the mounting process of mounting an electronic component on the printed wiring board, first, a solder paste containing solder is applied to the pads. Next, the electronic component is mounted on the substrate in contact with the solder paste, and reflow soldering is performed. By the reflow soldering, the solder paste melts. At this time, the solder in the solder paste provided on the solder resist flows onto the divided pads where the solder resist is not provided. As a result, each divided pad of the printed wiring board is connected to the electronic component by solder.

[0026] Heat generated in an electronic component is conducted to a pad via solder. The heat conducted to the pad is dissipated to the other main surface (the surface opposite to the surface on which the pad is provided) of the printed wiring board through a through hole that penetrates the printed wiring board at the position of the pad. That is, the through hole constitutes a heat dissipation path starting from the pad. In a conventional printed wiring board, the through hole is formed in a region where a solder resist is disposed. In this case, since the heat dissipation property of the through hole is low, heat tends to accumulate in the pad. As a result, the heat dissipation property of the electronic component may be reduced.

[0027] Therefore, the inventors of the present invention conducted in-depth research and came up with the idea of extending the solder resist to the edge of the pad and forming a hole portion that penetrates the pad and the base portion at a position different from the position where the solder resist is provided. Since the hole portion is located at a position different from the position where the solder resist is provided, it is filled with solder in the solder paste during reflow soldering. Thus, the heat generated in the electronic component is dissipated to the other main surface of the substrate via the solder disposed inside the hole portion, and the heat dissipation property of the electronic component is improved. Based on this new insight, the inventors of the present invention completed the following disclosure.

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In addition, this embodiment does not limit the present disclosure. And, in the drawings, the same reference numerals are assigned to substantially the same components.

[0029] And, hereinafter, for the sake of convenience of explanation, terms indicating directions such as "upper" and "lower" are used, but these terms do not limit the usage state of the substrate and the module of the present disclosure.

[0030] <Embodiment>

[0031] Use Figure 1 And Figure 2 to describe the substrate of the embodiment of the present disclosure. Figure 1 is a top view of the substrate of the embodiment of the present disclosure. Figure 2 is a cross-sectional view taken along the Figure 1 II-II line.

[0032] Electronic components such as power semiconductors and large-scale integrated circuits (LSIs) can be mounted on the substrate 1. In this specification, the "substrate" includes both a printed wiring board on which a printed wiring is formed and on which no electronic component is mounted, and a printed circuit board on which an electronic component is mounted on the printed wiring board. That is, in the substrate of this specification, an electronic component may already be mounted, or no electronic component may be mounted.

[0033] As Figure 1 And Figure 2As shown, the substrate 1 of the present embodiment is a printed wiring board. The substrate 1 includes: a plate-shaped base portion 2 having one main surface 2a and another main surface 2b; and metal-containing pads 3 and 4 provided on one main surface 2a. One main surface 2a is covered with a solder resist 5 except for the pads 3 and 4. Among the pads 3 and 4, the pad 3 corresponds to the pad in the present disclosure. A solder resist 6 is provided on a part of the surface 30 of the pad 3. That is, the solder resist 5 is provided on one main surface 2a of the base portion 2, and the solder resist 6 is provided on the pad 3. A plurality of holes 8 penetrating the pad 3 and the base portion 2 are formed at positions on the pad 3 different from the position where the solder resist 6 is provided.

[0034] As Figure 1 shown, when the base portion 2 of the present embodiment is viewed from above along the thickness direction of the base portion 2, it is rectangular. In the following description, the long side direction of the base portion 2 when viewed from above may be referred to as the X direction, the short side direction of the base portion 2 when viewed from above may be referred to as the Y direction, and the thickness direction of the base portion 2 may be referred to as the Z direction. The X direction is orthogonal to the Y direction, and the Z direction is orthogonal to both the X direction and the Y direction.

[0035] As Figure 2 shown, the base portion 2 of the present embodiment is an insulating layer in a copper-clad laminate for a double-sided substrate. That is, the substrate 1 of the present embodiment is a single-layer substrate. The material of this insulating layer is resin, glass, ceramic, etc. The base portion 2 may also have a laminated structure including two or more insulating layers and conductive layers disposed between these insulating layers to form wirings. That is, the substrate 1 may also be a multi-layer substrate.

[0036] Printed wirings may also be provided on one main surface 2a and another main surface 2b of the base portion 2 and on the conductive layers in the case where the substrate 1 is a multi-layer substrate. Through holes, via holes, etc. for connecting printed wirings located at different positions in the Z direction may also be provided in the base portion 2. As Figure 1 shown, the printed wiring provided on one main surface 2a is covered with a solder resist 5.

[0037] As Figure 2 shown, pads 9 containing metal may also be provided on the other main surface 2b. At least a part of the pad 9 of the present embodiment overlaps with the pad 3 provided on one main surface 2a in the Z direction. In the present embodiment, the plating layers 81 of the pad 3, the pad 9, and the holes 8 described later are integrated.

[0038] When an electronic component 10 (refer to Figure 3 ) is mounted on the substrate 1, the pad 3 is connected to the heat dissipation portion 11 of the electronic component 10. The pad 3 may be connected to the wiring provided on the base portion 2 or may be separated from the wiring. That is, the pad 3 may be electrically connected to the circuit formed on the substrate 1 or may not be connected to the circuit formed on the substrate 1.

[0039] AsFigure 1 As shown, the pad 3 in this embodiment is rectangular when viewed from above. Additionally, the shape of the pad 3 when viewed from above can also be circular, elliptical, polygonal, etc.

[0040] When an electronic component 10 (refer to Figure 3 ) is mounted on the substrate 1, the pad 4 is connected to the terminal portion 12 of the electronic component 10. Thus, the terminal portion 12 of the electronic component 10 is electrically connected to the circuit formed on the substrate 1. In this embodiment, eight pads 4 are arranged adjacent to the pad 3 in the X direction.

[0041] The materials of the pads 3, 4, and 9 are, for example, copper, gold, silver, palladium, nickel, platinum, or their alloys. The pads 3, 4, and 9 in this embodiment are copper foils of a copper-clad laminate.

[0042] A solder resist 6 is provided on a part of the surface 30 of the pad 3. The solder resist 6 among the solder resists 5 and 6 corresponds to the solder resist of the present disclosure. Molten solder hardly adheres to the solder resist 6.

[0043] As Figure 1 shown, the solder resist 6 extends between the plurality of hole portions 8 without overlapping the plurality of hole portions 8 when viewed from above, and abuts on the edge 31 of the pad 3 at at least one place. The solder resist 6 in this embodiment has two extended solder resists 61 and 62 that extend without crossing each other in one direction when viewed from above. The extended solder resist 61 and the extended solder resist 62 are in a straight line shape extending in the Y direction and are parallel to each other when viewed from above. Both end portions of each of the extended solder resists 61 and 62 abut on the edge 31 of the pad 3 when viewed from above. That is, each of the extended solder resists 61 and 62 extends to the edge 31 of the pad 3 at both end portions.

[0044] The number of the extended solder resists is not limited to two, and may be one or three or more. Also, as long as each of the extended solder resists extends as a whole in one direction, it may be, for example, a wavy line shape or a curved line shape. And, in the case where a plurality of extended solder resists are provided, as long as these extended solder resists each extend in one direction, they may not be parallel to each other.

[0045] As Figure 2 shown, a marking layer 7 is provided above the extended solder resist 62. The marking layer 7 constitutes at least a part of the marking shown when viewed from above. This marking can be a line, a graphic, a character, a number, a symbol, a dot-like identification code, a barcode, a two-dimensional code, a logo, etc.

[0046] The marking layer 7 can be provided in the entire area of the extended solder resist 62 when viewed from above, or can be provided only in a part of the area. As Figure 1As shown, the marking layer 7 of the present embodiment is provided in a linear shape over the entire length in the Y direction of the extended solder resist 62. That is, the two end portions of the marking layer 7 are in contact with the edges 31 of the pad 3 in a top view. The width of the marking layer 7 of the present embodiment in the X direction is shorter than the width of the extended solder resist 62 in the X direction.

[0047] The material of the marking layer 7 is a resin, ceramic, etc. that repels molten solder. The marking layer 7 of the present embodiment is a screen pattern.

[0048] The regions in the surface 30 of the pad 3 where the solder resist 6 is not disposed are divided by the solder resist 6 into a plurality of non-solder-resist regions 30A to 30C. In the present embodiment, the regions where the solder resist 6 is not disposed are divided by two extended solder resists 61 and 62 into three non-solder-resist regions 30A to 30C. In the present embodiment, the total area of the non-solder-resist regions 30A to 30C in a top view is larger than the total area of the solder resist 6 in a top view.

[0049] Each of the extended solder resists 61 and 62 extends along the Y direction. Therefore, each of the non-solder-resist regions 30A to 30C is not divided by the solder resist 6 in the Y direction. Thus, in each of the non-solder-resist regions 30A to 30C, heat can be conducted in the Y direction over the entire length of the pad 3 in the Y direction.

[0050] When the pad 3 is viewed from above, the two extended solder resists 61 and 62 and the three non-solder-resist regions 30A to 30C are alternately arranged in a direction crossing the extending direction of the extended solder resists 61 and 62, for example, the Y direction.

[0051] A plurality of hole portions 8 are formed at positions on the pad 3 different from the positions where the solder resist 6 is provided. The plurality of hole portions 8 are formed in at least two of the non-solder-resist regions 30A to 30C. As Figure 2 shown, each of the hole portions 8 penetrates the pad 3 and the base portion 2 in the Z direction. The hole portion 8 of the present embodiment also penetrates the pad 9 provided on the other main surface 2b.

[0052] As Figure 1 shown, the hole portion 8 of the present embodiment is a through hole that is circular in a top view, and three are formed in each of the non-solder-resist regions 30A to 30C. As Figure 2 shown, a plating layer 81 is provided on the inner surface of the hole portion 8.

[0053] As Figure 1 shown, the hole portions 8 of the present embodiment are arranged in the X direction and the Y direction. It should be noted that the plurality of hole portions 8 are not limited to the above situation, and may be arranged only in either the X direction or the Y direction, or may not be arranged.

[0054] The number of holes 8 in each of the non-solder resist areas 30A to 30C may be one or more and different from each other. As long as the holes 8 are formed in at least two non-solder resist areas, there may also be non-solder resist areas in which the holes 8 are not formed.

[0055] <Method for manufacturing a substrate>

[0056] Using Figure 4 , an example of the method for manufacturing the substrate of the present disclosure will be described. Figure 4 Is a diagram showing Figure 1 Flowcharts of the manufacturing process of the substrate and the mounting process of mounting an electronic component on the substrate.

[0057] First, a base 2 is prepared (step S11). The base 2 is, for example, a copper-clad laminate for a double-sided substrate having copper foils provided on the entire surfaces of one main surface 2a and the other main surface 2b. The copper foils constitute the pads 3, 4, 9 and the printed wiring on one main surface 2a and the other main surface 2b.

[0058] Next, holes 8 are formed in the base 2 (step S12). The holes 8 are formed, for example, by grinding with a drill or laser processing.

[0059] Next, a plating layer 81 is formed inside the holes 8 (step S13). The plating layer 81 is formed, for example, by electroless copper plating.

[0060] Next, the copper foils on one main surface 2a and the other main surface 2b are etched to form conductor patterns constituting the printed wiring (step S14). This etching is performed, for example, by pasting a dry film on one main surface 2a and the other main surface 2b, curing the areas other than the conductor pattern of the dry film, and then exposing the base 2 to an etching solution. At this time, the cured dry film is removed after etching.

[0061] Next, solder resists 5 and 6 are provided on one main surface 2a and the other main surface 2b, except for the non-solder resist areas 30A to 30C and the areas of the pads 4 and 9 (step S15). The solder resists 5 and 6 are provided, for example, by screen printing, spraying, or curtain coating.

[0062] Next, a marking layer 7 is laminated on the extended solder resist 62 (step S16). The marking layer 7 is printed, for example, by screen printing.

[0063] <Method for mounting an electronic component>

[0064] Next, using Figure 3 And Figure 4 , an example of the process of mounting the electronic component 10 on the substrate 1 will be described. Figure 3 Is a cross-sectional view showing the module of the embodiment of the present disclosure, corresponding to Figure 2 As Figure 3As shown, the electronic component 10 mounted on the substrate 1 has a heat dissipation portion 11 provided on the surface and a terminal portion 12. The heat dissipation portion 11 can be connected to the pad 3, and the terminal portion 12 can be connected to the pad 4.

[0065] In the mounting process of the electronic component 10, first, a solder paste containing solder is applied to the pads 3 and 4 (step S21). In this example, the solder paste is applied to the entire surface of the pad 3. That is, the solder paste is applied to the non-solder mask areas 30A to 30C, the solder mask 6, and the marking layer 7. This application is performed by, for example, screen printing.

[0066] Next, in the state where the electronic component 10 is mounted on the substrate 1, reflow soldering is performed (step S22). The solder contained in the solder paste melts by reflow soldering. Since the solder mask 6 and the marking layer 7 repel the molten solder, the solder contained in the solder paste on the solder mask 6 and the marking layer 7 flows toward the non-solder mask areas 30A to 30C. Also, the flux, moisture, etc. contained in the solder paste volatilize during reflow soldering. As a result, spaces 101 and 102 are formed between the heat dissipation portion 11 and the solder mask 6.

[0067] A part of the molten solder on the non-solder mask areas 30A to 30C enters the hole portion 8. The remaining part of the molten solder remains on the non-solder mask areas 30A to 30C. The gas generated due to the volatilization of the flux, moisture, etc. contained in the solder paste is discharged to the outside of the pad 3 through the spaces 101 and 102.

[0068] When the solder paste is applied to the non-solder mask areas 30A to 30C and the solder mask 6, in each of the non-solder mask areas 30A to 30C, in addition to the solder in the solder paste applied thereon, the solder in the solder paste applied on the solder mask 6 also flows in. As a result, the amount of the molten solder on the non-solder mask areas 30A to 30C increases, so that the possibility of solder shortage on the non-solder mask areas 30A to 30C due to the solder entering the hole portion 8 can be reduced. Also, compared with the structure without the solder mask 6, the filling rate of the solder in the plurality of hole portions 8 can be improved.

[0069] In this specification, "filling" means disposing an object (e.g., solder) in all or part of a certain space (e.g., the internal cavity of a hole portion). And the filling rate is, for example, the ratio obtained by dividing the total volume of the solder disposed in the internal cavity of the hole portion 8 by the total volume of the internal cavity of the hole portion 8.

[0070] The shorter the distance between the solder mask 6 and the hole portion 8 in a top view, the easier it is for the solder contained in the solder paste on the solder mask 6 to enter the hole portion 8 due to the flow of the solder. On the other hand, when the solder mask 6 and the hole portion 8 are in contact with each other in a top view, there is a possibility that the solder mask 6 may hinder the solder from entering the hole portion 8. Therefore, in the embodiment of the present disclosure, each hole portion 8 is separated from the solder mask 6 in a top view, that is, not in contact.

[0071] Use Figure 3 The module 100 with the electronic component 10 mounted on the substrate 1 will be described. The module 100 may also include a heat sink 21 provided on the pad 9 on the other main surface 2b and a heat radiator 22 connected to the heat sink 21.

[0072] The electronic component 10 is mounted on the substrate 1, for example, by the mounting process as described above. In the module 100, the heat dissipation part 11 of the electronic component 10 and the pad 3 of the substrate 1 sandwich solder 13A to 13C and solder resist 6 in the Z direction.

[0073] The heat dissipation part 11 of the electronic component 10 is connected to the non-solder resist regions 30A to 30C of the pad 3 by the solidified solder 13A to 13C. Each of the solders 13A to 13C is disposed between the pad 3 and the heat dissipation part 11 and extends inside the hole part 8. That is, the hole part 8 is filled with the solder 13A to 13C.

[0074] The heat generated in the electronic component 10 is conducted to the other main surface 2b of the base part 2 via the heat dissipation part 11, the solder 13A to 13C, the pad 3, and the plating 81 of the hole part 8. In addition, in Figure 3 the example shown, the amount of solder filled in each hole part 8 is the same, but they may also be different. And if at least one of the plurality of hole parts 8 is filled with solder, there may also be hole parts 8 that are not filled with solder.

[0075] The terminal part 12 and the pad 4 are connected by the solder 14 from the solder paste applied to the pad 4. Thus, the electronic component 10 is electrically connected to the circuit of the substrate 1.

[0076] The heat sink 21 of the present embodiment has one main surface 21a in contact with the pad 9 and another main surface 21b opposite to the one main surface 21a. The heat radiator 22 is in contact with the another main surface 21b. Thus, the heat generated in the electronic component 10 is conducted to the heat radiator 22 via the heat dissipation part 11, the solder 13A to 13C, the pad 3, the plating 81 of the hole part 8, the pad 9, and the heat sink 21, and is dissipated to the outside of the module 100.

[0077] In the substrate 1 according to the present embodiment, a solder paste containing solder is applied on the solder resist 6. When the solder is melted by reflow soldering, the solder flows from the position on the solder resist 6 to the non-solder resist regions 30A to 30C. A part of the solder that has flowed into the non-solder resist regions 30A to 30C enters the plurality of hole parts 8 and solidifies inside the plurality of hole parts 8. The heat dissipation property of the hole part 8 filled with the solder 13A to 13C is higher than that of the hole part not filled with solder. Therefore, the amount of heat conducted from the one main surface 2a of the base part 2 to the other main surface 2b via the hole part 8 increases, and thus, the heat dissipation property of the electronic component can be improved.

[0078] Further, according to this structure, molten solder flows out from the solder resist 6, whereby spaces 101 and 102 are formed between the electronic component 10 connected to the pad 3 and the solder resist 6. Since the solder resist 6 extends to the edge 31 of the pad 3, the spaces 101 and 102 communicate with the outside of the pad 3. Through the spaces 101 and 102, the gas generated when the solder melts can be discharged to the outside of the pad 3. Therefore, it is possible to suppress the generation of voids in the solder 13A to 13C on the pad 3 and improve the heat dissipation of the electronic component 10 connected to the pad 3.

[0079] In the case where the plurality of hole portions 8 are formed only in one non-solder-resist region, since the molten solder enters the plurality of hole portions 8, there may be insufficient solder on this one non-solder-resist region. The insufficient solder on this one non-solder-resist region leads to the generation of voids. On the other hand, according to the substrate 1 of the present embodiment, since the plurality of hole portions 8 are dispersedly formed in the plurality of non-solder-resist regions 30A to 30C, the number of hole portions 8 formed in one non-solder-resist region can be reduced. Thereby, the possibility of insufficient solder on each of the non-solder-resist regions 30A to 30C can be reduced. Therefore, it is possible to further suppress the generation of voids in the solder 13A to 13C.

[0080] Further, according to the substrate 1 of the present embodiment, the plurality of extended solder resists 61 and 62 extend along one direction (for example, the Y direction) on the pad 3 without crossing each other. Therefore, each of the non-solder-resist regions 30A to 30C is not divided in the extending direction of the extended solder resist. Therefore, in each of the non-solder-resist regions 30A to 30C and the solder 13A to 13C disposed thereon, heat is dispersed in this extending direction. Therefore, in each of the non-solder-resist regions 30A to 30C, it is possible to suppress the reduction in the heat dissipation of the electronic component 10 caused by heat concentration in a part.

[0081] Further, according to the substrate 1 of the present embodiment, the solder paste coated on the marking layer 7 is disposed at a position higher than the solder paste coated on the solder resist 6 in the thickness direction (for example, the Z direction) of the base 2. Therefore, when the solder in the solder paste coated on the marking layer 7 flows toward the non-solder-resist regions 30A to 30C, it flows more greatly than the solder in the solder paste coated on the solder resist 6. Through this large flow, the molten solder easily enters the plurality of hole portions 8.

[0082] <Modified Example>

[0083] Use Figure 5 A first modified example of the pad 3 of the foregoing embodiment will be described. Figure 5 Is a top view enlarged view showing a first modified example of the pad in the substrate of Figure 1 . In Figure 5 The pad 3A shown and Figure 1In the pad 3 shown, the configuration of the solder resist 6 is different. Regarding the other parts, since they are the same as or similar to the aforementioned pad 3, the description may sometimes be omitted.

[0084] In Figure 5 In the pad 3 shown, the solder resist 6 has two first extended solder resists 61 and 62 and two second extended solder resists 63 and 64. The first extended solder resists 61 and 62 in this modified example are the same as or similar to the extended solder resists 61 and 62 in the aforementioned embodiment. The first extended solder resists 61 and 62 extend without crossing each other along the first direction in a top view, and are connected to the edge 31 of the pad 3 at both ends. The first extended solder resists 61 and 62 in this modified example extend parallel to each other along the Y direction. That is, in this modified example, the Y direction corresponds to the first direction.

[0085] The second extended solder resists 63 and 64 extend without crossing each other along a second direction different from the first direction in a top view, and are connected to the edge 31 of the pad 3 at both ends. The second extended solder resists 63 and 64 in this modified example extend parallel to each other along the X direction orthogonal to the Y direction. That is, in this modified example, the X direction corresponds to the second direction. The two first extended solder resists 61 and 62 cross the two second extended solder resists 63 and 64. That is, the solder resist 6 is arranged in a grid pattern on the pad 3.

[0086] The regions on the surface 30 of the pad 3 where the solder resist 6 is not arranged are divided into nine non-solder resist regions 30D to 30L by the first extended solder resists 61 and 62 and the second extended solder resists 63 and 64. One hole 8 is formed in each of the non-solder resist regions 30D to 30L. In addition, the number of holes 8 formed in each of the non-solder resist regions 30D to 30L is not limited to one.

[0087] In addition, the first extended solder resists 61 and 62 and the second extended solder resists 63 and 64 only need to extend along the first direction or the second direction, and they may not be parallel to each other respectively. Also, the first extended solder resists 61 and 62 and the second extended solder resists 63 and 64 only need to extend in different directions, and they may not be orthogonal.

[0088] In the substrate 1 with the pad 3A having the first modification example, compared with the structure having only one of the first extension solder resistants 61 and 62 and the second extension solder resistants 63 and 64, solder flows into each hole portion 8 from more directions. For example, in the case of the structure without the second extension solder resistants 63 and 64, in the hole portion 8 sandwiched by the two first extension solder resistants 61 and 62, solder flows in from the two first extension solder resistants 61 and 62 located on both sides of the hole portion 8, that is, from two directions. On the other hand, in the hole portion 8 surrounded by the two first extension solder resistants 61 and 62 and the two second extension solder resistants 63 and 64, solder flows in from the two first extension solder resistants 61 and 62 and the two second extension solder resistants 63 and 64 surrounding the hole portion 8, that is, from four directions. Thus, the molten solder easily enters the plurality of hole portions 8.

[0089] Figure 6 is a top view of the substrate according to an embodiment of the present disclosure and is a view showing a second modification example of the pad. In Figure 6 the shown substrate 1, eight pads 4 are arranged adjacent to the pad 3B in the Y direction.

[0090] A plurality of hole portions 8 are formed in the pad 3B, and the plurality of hole portions 8 form a plurality of columns extending along the Y direction and arranged in the X direction. In each column, the hole portions 8 are arranged at equal intervals. The plurality of columns are formed by arranging groups of two columns in the X direction. In the two columns, the hole portions 8 in one column are offset from the hole portions 8 in the other column in the Y direction. The hole portions 8 in one column of each group are arranged along the X direction with respect to each other, and the hole portions 8 in the other column of each group are also arranged along the X direction with respect to each other. That is, the plurality of hole portions 8 also form a plurality of columns arranged along the Y direction.

[0091] One non-solder resist region 30M extending along the X direction and a non-solder resist region 30N extending along the Y direction are provided in the pad 3B. One column of the plurality of columns arranged along the Y direction is arranged in the non-solder resist region 30M. That is, the width of the non-solder resist region 30M in the Y direction is larger than the diameter of the hole portion 8. In the present embodiment, one non-solder resist region 30M extends in the central portion of the pad 3B in the Y direction. Thirteen non-solder resist regions 30N intersect the non-solder resist region 30M respectively and extend along the columns of the hole portions 8 arranged in the X direction. The hole portions 8 constituting each column arranged in the X direction are included in each non-solder resist region 30N in a top view.

[0092] The surface 30 of the pad 3B is covered with the solder resist 6 except for the non-solder resist regions 30M and 30N. That is, all the hole portions 8 are arranged in the region of the surface 30 not covered by the solder resist 6.

[0093] Figure 7 is a top view showing Figure 6 the third modification example of the pad in the substrate of. AsFigure 7 As shown, three non-solder mask areas 30M and a plurality of non-solder mask areas 30N intersecting each non-solder mask area 30M are provided in the pad 3C. In the present embodiment, two of the plurality of hole portions 8 forming columns arranged in the X direction are arranged in each non-solder mask area 30N.

[0094] Figure 8 It is Figure 6 a top view of a fourth modified example of a pad in a substrate of. As Figure 8 shown, two non-solder mask areas 30M and a plurality of non-solder mask areas 30N extending in one direction along the Y direction from each non-solder mask area 30M are provided in the pad 3D. In addition, a non-solder mask area 30P extending in the X direction and a non-solder mask area 30Q extending in the Y direction from the non-solder mask area 30P are provided in the pad 3D.

[0095] The width of the non-solder mask area 30P in the Y direction is smaller than the diameter of the hole portion 8. That is, the non-solder mask area 30P does not include the hole portion 8 in a top view. The hole portions 8 sandwiched between the non-solder mask area 30M and the non-solder mask area 30P in the Y direction are alternately arranged in the non-solder mask area 30N or the non-solder mask area 30Q in the X direction.

[0096] Figure 9 It is Figure 6 a top view of a fifth modified example of a pad in a substrate of. As Figure 9 shown, in the pad 3E, in addition to one non-solder mask area 30M and one non-solder mask area 30N, a plurality of non-solder mask areas 30R are also provided. The non-solder mask area 30N intersects one end portion ( Figure 9 the right end portion in) of the non-solder mask area 30M. The non-solder mask area 30R extends from either the non-solder mask area 30M or 30N in such a manner that it moves away from the non-solder mask area 30M in the Y direction as it moves away from the non-solder mask area 30N in the X direction. In the present embodiment, the plurality of non-solder mask areas 30R extend parallel to each other.

[0097] Figure 10 It is Figure 6 a top view of a sixth modified example of a pad in a substrate of. As Figure 10 shown, a plurality of non-solder mask areas 30S surrounding each hole portion 8 are provided in the pad 3F. The non-solder mask area 30S has the same shape as the hole portion 8 in a top view.

[0098] In addition, the present disclosure is not limited to the foregoing embodiments and can be implemented in various other ways. For example, in the above, the hole portion 8 is a circular through-hole, but the present disclosure is not limited thereto. The shape of the hole portion 8 in plan view may also be an ellipse, a polygon, etc. For example, the shape of the hole portion 8 in plan view may also be a rectangle extending in the extending direction of each non-solder resist region 30A to 30C.

[0099] The present disclosure has been fully described with reference to the accompanying drawings in connection with preferred embodiments, but various modifications and corrections will be apparent to those skilled in the art. Such modifications and corrections should be understood to be included therein as long as they do not depart from the scope of the present disclosure of the appended claims.

[0100] <Summary of the Embodiment>

[0101] According to a first aspect of the present disclosure, there is provided a substrate including: a plate-shaped base; pads provided on one main surface of the base and including metal; and a solder resist provided on a part of the surface of the pads, and a plurality of hole portions penetrating the pads and the base in the thickness direction of the base are formed at positions different from the positions where the solder resist is provided. In plan view when viewed along the thickness direction of the base, the solder resist extends between the plurality of hole portions without overlapping the plurality of hole portions and abuts on the edge of the pads.

[0102] According to a second aspect of the present disclosure, there is provided the substrate according to the first aspect, wherein the solder resist abuts on the edge of the pads at two or more positions in the plan view, and the regions of the surface of the pads where the solder resist is not disposed are divided into a plurality of non-solder resist regions by the solder resist, and the plurality of hole portions are formed in at least two of the plurality of non-solder resist regions.

[0103] According to a third aspect of the present disclosure, there is provided the substrate according to the second aspect, wherein the solder resist has a plurality of extending solder resists that extend without crossing each other in one direction in the plan view and abut on the edge of the pads at both ends, and the plurality of extending solder resists and the plurality of non-solder resist regions are alternately arranged in the plan view.

[0104] According to a fourth aspect of the present disclosure, there is provided the substrate according to the second aspect, wherein the solder resist includes: a plurality of first extending solder resists that extend without crossing each other in a first direction in the plan view and abut on the edge of the pads at both ends; and a plurality of second extending solder resists that extend without crossing each other in a second direction different from the first direction in the plan view and abut on the edge of the pads at both ends, and the plurality of first extending solder resists cross the plurality of second extending solder resists.

[0105] According to a fifth aspect of the present disclosure, there is provided a substrate according to any one of the first to fourth aspects, wherein a marking layer constituting a mark is provided on the solder resist.

[0106] According to a sixth aspect of the present disclosure, there is provided a module including: a substrate according to any one of the first to fifth aspects; an electronic component mounted on the substrate and having a heat dissipation portion opposed to the pad; and solder disposed between the heat dissipation portion of the electronic component and the pad of the substrate and inside at least one of the plurality of hole portions to connect the heat dissipation portion and the pad.

[0107] [Industrial Applicability]

[0108] The substrate of the present disclosure can suppress the generation of voids in the solder on the pad and improve the heat dissipation of the electronic component connected to the pad. Therefore, it is useful for substrates on which electronic components such as power semiconductors and LSIs are mounted.

[0109] Description of Reference Numerals

[0110] 1 Substrate

[0111] 2 Base

[0112] 2a One main surface

[0113] 3, 3A to 3F Pads

[0114] 30 Surface

[0115] 30A to 30S Non-solder resist regions

[0116] 31 Edge

[0117] 6 Solder resist

[0118] 61, 62 Extended solder resist (first extended solder resist)

[0119] 63, 64 Second extended solder resist

[0120] 7 Marking layer

[0121] 8 Hole portion

[0122] 10 Electronic component

[0123] 11 Heat dissipation portion

[0124] 13A to 13C Solder

[0125] 100 Module

Claims

1. A substrate, comprising: A plate - shaped base; A pad, which is provided on one main surface of the base and contains metal; and A solder resist, which is provided on a part of the surface of the pad, A plurality of holes that penetrate the pad and the base in the thickness direction of the base are formed at positions different from the position where the solder resist is provided on the pad, When viewed from above along the thickness direction of the base, the solder resist extends between the plurality of holes without overlapping with the plurality of holes and abuts against the edge of the pad.

2. The substrate according to claim 1, wherein The solder resist abuts against the edge of the pad at two or more positions when viewed from above, The area of the surface of the pad where the solder resist is not disposed is divided into a plurality of non - solder - resist areas by the solder resist, The plurality of holes are formed in at least two of the plurality of non - solder - resist areas.

3. The substrate according to claim 2, wherein The solder resist has a plurality of extended solder resists, and the plurality of extended solder resists extend without crossing each other in one direction when viewed from above and abut against the edge of the pad at both ends, The plurality of extended solder resists and the plurality of non - solder - resist areas are alternately arranged when viewed from above.

4. The substrate according to claim 2, wherein The solder resist includes: A plurality of first extended solder resists, which extend without crossing each other in a first direction when viewed from above and abut against the edge of the pad at both ends; And A plurality of second extended solder resists, which extend without crossing each other in a second direction different from the first direction when viewed from above and abut against the edge of the pad at both ends, The plurality of first extended solder resists cross the plurality of second extended solder resists.

5. The substrate according to any one of claims 1 to 4, wherein A marking layer forming a mark is provided on the solder resist.

6. A module, comprising: The substrate according to any one of claims 1 to 5; An electronic component, which is mounted on the substrate and has a heat - dissipation part opposed to the pad; and Solder, which is disposed between the heat - dissipation part of the electronic component and the pad of the substrate and inside at least one of the plurality of holes, and connects the heat - dissipation part and the pad.

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