Mounting board

Abstract

To provide an implementation wiring board capable of avoiding holes in side-filled resin.SOLUTION: The implementation wiring board is a printed wiring board mounted with electronic components. The electronic components are mounted on the surface of a printed wiring board and the outer circumference thereof is applied with side-fill resin. A through-hole communicating to a space that is formed by the printed wiring board, the electronic components, and the side fill resin is provided on at least one of the printed wiring board and the electronic component.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a mounting substrate. [Background technology]

[0002] Patent Document 1 discloses a method for reinforcing the connection of a semiconductor component to a substrate by using a side fill, in which resin is applied around the semiconductor component, rather than an underfill, in which resin is applied to the gap between the surface of the substrate and the underside of the semiconductor component, when flip-chip mounting the semiconductor component to the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-118208 Summary of the Invention [Problem to be solved by the invention]

[0004] When applying a side fill, which is a resin applied around an electronic component, the space between the surface of the board and the underside of the electronic component is sealed with the side fill resin. Therefore, when the side fill resin is heated to harden, for example, the air or moisture in the sealed space may expand, causing a hole in the side fill resin.

[0005] An object of the present disclosure is to prevent holes from being formed in the side-fill resin of a mounting board. [Means for solving the problem]

[0006] One aspect of the present disclosure provides a mounting board in which an electronic component is mounted on a printed circuit board, the electronic component being surface-mounted on the printed circuit board and having a side-fill resin applied to its outer periphery, and a through-hole connecting to a space formed by the printed circuit board, the electronic component, and the side-fill resin being provided in at least one of the printed circuit board and the electronic component. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to prevent holes from being formed in the side-fill resin on the mounting board. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view showing an example of a mounting board to which side fill is applied around electronic components. [Figure 2] Cross-sectional view showing an example of a mounting board with side fill applied around a QFN (Quad Flat Non-leaded package) [Figure 3] A cross-sectional view showing an example of a mounting board with side fill applied around a BGA (Ball Grid Array) [Figure 4] FIG. 1 is a cross-sectional view showing an example of a through-hole provided in a mounting substrate to which a side fill is applied around a QFN according to an embodiment of the present invention. [Figure 5] FIG. 1 is a cross-sectional view showing an example of a through-hole provided in a mounting substrate to which a side fill is applied around a BGA according to an embodiment of the present invention. [Figure 6] FIG. 1 is a plan view showing an example of a printed circuit board provided with a through-hole in a mounting board including a QFN according to an embodiment of the present invention; [Figure 7] FIG. 1 is a plan view showing an example of a mounting board including a QFN according to an embodiment of the present invention, in which a board through-hole is provided in a printed circuit board and a component through-hole is provided in the QFN. [Figure 8] FIG. 1 is a plan view showing an example in which a substrate through-hole is provided at a corner of a mounting substrate including a QFN according to an embodiment of the present invention; [Figure 9A]FIG. 10 is a plan view showing an example in which the size of the GND land is reduced and a substrate through-hole is provided in a mounting substrate including a QFN according to the present embodiment. [Figure 9B] FIG. 10 is a cross-sectional view showing an example in which the size of the GND land is reduced and a substrate through-hole is provided in the mounting substrate having the QFN according to the present embodiment. [Figure 10] FIG. 1 is a plan view showing an example in which a portion of a GND land and a GND terminal are cut to provide through holes in a mounting substrate including a QFN according to the present embodiment. [Figure 11A] FIG. 10 is a plan view showing a second example in which the GND lands are divided and a substrate through-hole is provided between the divided GND lands in a mounting substrate having a QFN according to the present embodiment. [Figure 11B] FIG. 10 is a plan view showing a second example in which the GND lands are divided and a substrate through-hole is provided between the divided GND lands in the mounting substrate having the QFN according to the present embodiment. [Figure 11C] FIG. 10 is a cross-sectional view showing an example in which the GND lands are divided and a substrate through-hole is provided between the divided GND lands in a mounting substrate having a QFN according to the present embodiment. [Figure 12] FIG. 1 is a plan view showing an example of a printed circuit board provided with a board through-hole in a mounting board including a BGA according to an embodiment of the present invention; [Figure 13] FIG. 1 is a plan view showing a first example of a printed circuit board and a BGA mounting board having a through hole according to an embodiment of the present invention; [Figure 14A] FIG. 10 is a plan view showing a second example of a mounting board including a BGA according to the present embodiment, in which through holes are provided in the printed circuit board and the BGA; [Figure 14B] FIG. 10 is a cross-sectional view showing a second example of a mounting board including a BGA according to the present embodiment, in which through holes are provided in the printed circuit board and the BGA. [Figure 15] FIG. 1 is a plan view showing a first example of a mounting board including a BGA according to an embodiment of the present invention, in which solder balls are not provided on a portion of the BGA, and substrate through-holes are provided without providing lands on a printed circuit board at a position opposite the portion where the solder balls are not provided. [Figure 16]FIG. 10 is a plan view showing a second example of a mounting board including a BGA according to the present embodiment, in which solder balls are not provided on a portion of the BGA, and substrate through-holes are provided without providing lands on a portion of the printed circuit board opposite the portion where the solder balls are not provided. [Figure 17A] FIG. 1 is a plan view showing an example of a mounting board including a BGA according to the present embodiment, in which a component through-hole is provided without providing a solder ball in a part of the BGA, and a board through-hole is provided without providing a land in a position of the printed circuit board opposite the part without the solder ball. [Figure 17B] FIG. 17B is a cross-sectional view showing an example in which a component through-hole is provided in a part of the BGA in the mounting board shown in FIG. 17A. [Figure 18] FIG. 1 is a plan view showing an example of a mounting substrate including a QFN according to an embodiment of the present invention, in which the corners of the QFN are not covered with a reinforcing resin of a side fill. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with appropriate reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0010] (Embodiment 1) Fig. 1 is a plan view showing an example of a mounting substrate 1 in which a side fill is applied around an electronic component 2. Fig. 2 is a cross-sectional view showing an example of a mounting substrate 1 in which a side fill is applied around a QFN (Quad Flat Non-leaded package) 2A. Fig. 3 is a cross-sectional view showing an example of a mounting substrate 1 in which a side fill is applied around a BGA (Ball Grid Array) 2B.

[0011] For ease of explanation, in this embodiment, as shown in Figures 1, 2, and 3, axes parallel to the surface of the printed circuit board 3 are defined as the X-axis and Y-axis, and an axis perpendicular to the surface of the printed circuit board 3 is defined as the Z-axis. For ease of explanation, the positive direction of the Z-axis may be referred to as "up" and the negative direction of the Z-axis may be referred to as "down." These directional expressions are used for ease of explanation and are not intended to limit the orientation of the structure during actual use.

[0012] The plan view (plan view) shown in FIG. 1 corresponds to a view showing the XY plane, and the cross-sectional views shown in FIGS. 2 and 3 correspond to views showing the ZX plane.

[0013] The mounting board 1 includes a printed circuit board 3 and an electronic component 2 surface-mounted on the printed circuit board 3. Examples of the electronic component 2 include a QFN2A (see FIG. 2) and a BGA2B (see FIG. 3). However, the electronic component 2 is not limited to these and may be a CSP (Chip Size Package), an LGA (Land Grid Array), a QFP (Quad Flat Package), or the like. The electronic component 2 may also be referred to by other terms such as a semiconductor device, a semiconductor package, or a surface-mount package.

[0014] When manufacturing the mounting board 1, the electronic component 2 is joined to the printed circuit board 3 by solder. However, in the case of mounting boards 1 used in environments subject to severe vibration and / or temperature changes, such as in vehicles (e.g., automobiles, motorcycles, tractors, ships, airplanes, trains, bicycles, etc.), cracks may occur in the solder (hereinafter referred to as solder joints 7) joining the electronic component 2 to the printed circuit board 3, and further reinforcement is required.

[0015] Therefore, when manufacturing the mounting board 1, a technique called side fill is used, in which a relatively viscous resin (hereinafter referred to as reinforcing resin 4) is applied around the electronic component 2 and heated to harden the reinforcing resin 4 and firmly secure the electronic component 2 to the printed circuit board 3. By applying the side fill, as described above, the electronic component 2 can be more firmly secured to the printed circuit board 3. In addition, by applying the side fill, the gap between the upper surface of the printed circuit board 3 and the lower surface of the electronic component 2 is sealed, thereby improving security performance and tamper resistance. In the following description, the gap formed by the electronic component 2, the printed circuit board 3, and the reinforcing resin 4 of the side fill will be referred to as the under-component space 5.

[0016] In side filling, the reinforcing resin 4 is heated to about 100 to 150 degrees Celsius to harden, but at this time, the air and moisture sealed in the space under the component 5 expand, which may cause a hole in part of the reinforcing resin 4. Furthermore, when the air and moisture in the space under the component 5 expand and break down the reinforcing resin 4 and eject it, there is a risk that the flux residue contained in the reinforcing resin 4 will spread onto the printed circuit board 3. The flux residue will cause quality defects in the mounted board 1.

[0017] Furthermore, in a mounting board 1 mounted on a vehicle or the like, the air and moisture in the sub-component space 5 repeatedly expand and contract due to temperature changes caused by heat generated during operation of the electronic components 2. The expansion and contraction of the air in the sub-component space 5 damages the solder joints 7.

[0018] Therefore, in this embodiment, a configuration of the mounting board 1 that prevents holes from being formed in the reinforcing resin 4 of the side fill will be described.

[0019] Fig. 4 is a cross-sectional view showing an example of a through-hole provided in a mounting substrate 1 in which a side fill is applied around a QFN 2A according to this embodiment. Fig. 5 is a cross-sectional view showing an example of a through-hole provided in a mounting substrate 1 in which a side fill is applied around a BGA 2B according to this embodiment. The cross-sectional views shown in Figs. 4 and 5 correspond to views of the ZX plane.

[0020] 4 or 5, in the mounting board 1, at least one of the printed circuit board 3 and the electronic component 2 is provided with a through hole 6 that connects to an under-component space 5 formed by the electronic component 2, the printed circuit board 3, and the side-fill reinforcing resin 4. One or more through holes 6 may be provided only in the printed circuit board 3, one or more through holes 6 may be provided only in the electronic component 2, or one or more through holes 6 may be provided each in the printed circuit board 3 and the electronic component 2.

[0021] This allows air and moisture in the sub-component space 5 to enter and exit through the through holes 6, so that even if the air and moisture in the sub-component space 5 expand due to heating, holes will not be formed in the reinforcing resin 4 of the side fill. Hereinafter, the through holes 6 formed in the printed circuit board 3 may be referred to as board through holes 6A, and the through holes 6 formed in the electronic components 2 may be referred to as component through holes 6B. The diameter of the through holes 6 may be 0.3 mm or more. However, the diameter of the through holes 6 may be smaller than 0.3 mm. Furthermore, the diameter of the board through holes 6A and the diameter of the component through holes 6B may be the same or different from each other.

[0022] The through holes 6 may be provided at positions different from the positions where the solder joints 7 are present (i.e., avoiding the solder joints 7). This makes it possible to prevent the through holes 6 from being blocked by solder melted by reflow, for example.

[0023] The through holes 6 may be located inside the area where the reinforcing resin 4 of the side fill penetrates into the space under the component 5. For example, if the electronic component 2 is a BGA2B, CSP, or LGA, the through holes 6 may be located inside the connection terminals 22 (e.g., solder balls 23) located on the outermost periphery of the electronic component 2. For example, if the electronic component 2 is a QFN2A, the through holes 6 may be located inside the connection terminals 22 located on the outer periphery of the electronic component 2. The reinforcing resin 4 used in the side fill has a higher viscosity than the resin used in the underfill, and therefore does not penetrate into the space under the component 5 as much as the underfill. Therefore, the reinforcing resin 4 of the side fill that penetrates into the space under the component 5 does not reach the through holes 6 located at the above-mentioned positions and does not block the through holes 6.

[0024] A plurality of through holes 6 may be provided. This allows air and moisture in the under-component space 5 to pass through the other unblocked through holes 6 even if one through hole 6 is blocked by the reinforcing resin 4 of the side fill.

[0025] Furthermore, the solder resist in the printed circuit board 3 does not need to be provided on the board through-hole 6A, which makes it possible to prevent the solder resist from blocking the board through-hole 6A.

[0026] The inner surface of the substrate through hole 6A may be plated. This makes it easier for flux residue to be discharged through the through hole 6. Alternatively, the inner surface of the substrate through hole 6A may not be plated. This prevents solder from adhering to the inner surface of the through hole 6.

[0027] Next, some examples of providing the through-holes 6 in the mounting substrate 1 will be shown.

[0028] FIG. 6 is a plan view showing an example in which a board through-hole 6A is provided in a printed circuit board 3 in a mounting board 1 including a QFN 2A according to this embodiment.

[0029] 6, the QFN 2A has a square GND terminal 21 in the center and a plurality of connection terminals 22 on the periphery. The printed circuit board 3, in the portion where the QFN 2A is mounted, has a GND land 31 to which the GND terminal 21 is joined, and a land 32 to which the connection terminal 22 is joined. The GND terminal 21 is joined to the GND land 31 by solder. The connection terminal 22 is joined to the land 32 by solder.

[0030] The substrate through-hole 6A may be provided in an area R1 between the GND land 31 and the land 32 (hereinafter referred to as a non-land area).

[0031] Two substrate through-holes 6A may be provided on either side of the GND land 31. For example, as shown in FIG. 6, the two substrate through-holes 6A may be provided on an extension of a diagonal line E1 of the GND land 31, with the GND land 31 in between.

[0032] This allows the two substrate through holes 6A to be positioned sufficiently apart from each other, thereby preventing the two substrate through holes 6A from being blocked by the side-fill reinforcing resin 4. The number of substrate through holes 6A is not limited to two, and may be one, or three or more.

[0033] FIG. 7 is a plan view showing an example in which a board through-hole 6A is provided in a printed circuit board 3 and a component through-hole 6B is provided in a QFN 2A in a mounting board 1 including a QFN 2A according to this embodiment.

[0034] Two board through holes 6A may be provided in the non-land area R1 of the printed circuit board 3, with the GND land 31 sandwiched between them. For example, the two board through holes 6A may be provided at positions on a first line L1 that passes through the center point P of the GND land 31 and is perpendicular to one side of the GND land 31, with the GND land 31 sandwiched between them. The number of board through holes 6A is not limited to two, and may be one, or three or more.

[0035] Two component through-holes 6B may be provided in a region Q1 (hereinafter referred to as non-contact region Q1) of the QFN 2A facing the non-land region R1, with the GND terminal 21 sandwiched between them. For example, the two component through-holes 6B may be provided on a second line L2 that passes through the center point P of the GND terminal 21 and is perpendicular to the first line L1, with the GND terminal 21 sandwiched between them. The number of component through-holes 6B is not limited to two, and may be one, or three or more.

[0036] This positions the two substrate through holes 6A and the two component through holes 6B sufficiently apart from each other, thereby avoiding the risk of all of the two substrate through holes 6A and the two component through holes 6B being blocked by the side fill reinforcing resin 4.

[0037] FIG. 8 is a plan view showing an example in which a substrate through-hole 6A is provided at a corner of a mounting substrate 1 including a QFN 2A according to this embodiment.

[0038] 8, if the non-land area R1 is narrow and it is difficult to provide the substrate through-holes 6A in the non-land area R1 as shown in FIG. 6 or 7, the substrate through-holes 6A may be provided in areas near the corners of the QFN 2A where there are no lands 32. The substrate through-holes 6A may be provided in all four corners or in any of the four corners. The number of substrate through-holes 6A may be any number from one to four.

[0039] This allows the four substrate through-holes 6A to be positioned sufficiently apart from one another, thereby preventing all of the four substrate through-holes 6A from being blocked by the reinforcing resin 4 of the side fill.

[0040] Fig. 9A is a plan view showing an example in which the size of GND land 31 is reduced and substrate through-hole 6A is provided in mounting substrate 1 including QFN 2A according to this embodiment. Fig. 9B is a cross-sectional view showing an example in which the size of GND land 31 is reduced and substrate through-hole 6A is provided in mounting substrate 1 including QFN 2A according to this embodiment. The cross-sectional view shown in Fig. 9B is a cross-sectional view taken along line AA in the plan view shown in Fig. 9A.

[0041] If the non-contact area Q1 between the GND terminal 21 and the connection terminal 22 of the QFN 2A is narrow, as shown in Figures 9A and 9B, the GND land 31 of the printed circuit board 3 may be made slightly smaller than the GND terminal 21 to widen the non-land area R1, and a board through-hole 6A may be provided in the non-land area R1.

[0042] 9B, a resin 41 such as solder resist may be provided to surround the solder joints 7 that join the GND lands 31 to the GND terminals 21. The resin provided to surround the solder joints 7 is called protective resin 41. This protective resin 41 prevents the board through-holes 6A from being blocked by flux residue at the solder joints 7 that join the GND lands 31 to the GND terminals 21. In addition, the protective resin 41 prevents the QFN 2A from sinking in the direction approaching the printed circuit board 3, thereby preventing the board through-holes 6A from being blocked by sinking of the QFN 2A.

[0043] FIG. 10 is a plan view showing an example in which a through hole 6 is provided by cutting a part of the GND land 31 and the GND terminal 21 in the mounting substrate 1 including the QFN 2A according to this embodiment.

[0044] When the non-contact area Q1 between the GND terminal 21 and the connection terminal 22 of the QFN 2A is narrow, a portion of the GND land 31 and the GND terminal 21 may be cut, and a substrate through-hole 6A and / or a component through-hole 6B may be provided in the cut area (hereinafter referred to as a cut area) 42. For example, as shown in Fig. 10, two cut areas 42 may be provided on a first line L1 that passes through the center point P of the GND land 31 and is perpendicular to one side of the GND land 31, with the GND land 31 sandwiched between them, and two more cut areas 42 may be provided on a second line L2 that passes through the center point P of the GND terminal 21 and is perpendicular to the first line L1, with the GND terminal 21 sandwiched between them. This makes it possible to provide the substrate through-hole 6A and / or the component through-hole 6B even when the non-contact area Q1 is narrow.

[0045] FIG. 11A is a plan view showing a first example in which GND lands 31 are divided in mounting substrate 1 including QFN 2A according to this embodiment, and substrate through-holes 6A are provided between the divided GND lands 31. FIG. Fig. 11B is a plan view showing a second example in which GND lands 31 are divided in mounting substrate 1 including QFN 2A according to the present embodiment and substrate through-holes 6A are provided between the divided GND lands 31. Fig. 11C is a cross-sectional view showing an example in which GND lands 31 are divided in mounting substrate 1 including QFN 2A according to the present embodiment and substrate through-holes 6A are provided between the divided GND lands 31. The cross-sectional view shown in Fig. 11C is a cross-sectional view taken along line BB in the plan view shown in Fig. 11B.

[0046] If the non-contact area Q1 between the GND terminal 21 and the connection terminal 22 of the QFN 2A is narrow, the GND land 31 of the printed circuit board 3 may be divided, and a substrate through-hole 6A may be provided in the non-land area R1 between each divided GND land (hereinafter referred to as divided GND land 43), as shown in FIG. 11A or 11B.

[0047] 11A, the GND land 31 is divided into four parts in a cross shape, and a substrate through-hole 6A is provided in the center of a cross-shaped non-land area R1 formed between the four divided GND lands 43. Alternatively, as shown in Fig. 11B, the GND land 31 is divided into two parts in the X-axis direction, and a substrate through-hole 6A is provided in the center of a horizontally elongated non-land area R1 formed between the two divided GND lands 43. This makes it possible to provide the substrate through-hole 6A even when the non-contact area Q1 is narrow.

[0048] 11C , protective resin 41 may be provided to surround solder joint 7 that joins split GND land 43 of printed circuit board 3 to GND terminal 21 of QFN 2A. This protective resin 41 prevents flux residue from solder joint 7 that joins split GND land 43 to GND terminal 21 from blocking substrate through-hole 6A. In addition, protective resin 41 prevents QFN 2A from sinking in the direction approaching printed circuit board 3, thereby preventing substrate through-hole 6A from being blocked by sinking of QFN 2A.

[0049] 11A, the substrate through-hole 6A may be provided at the end of a cross-shaped non-land area R1. Alternatively, as shown in Fig. 11B, the substrate through-hole 6A may be provided at the end of a horizontally elongated non-land area R1. The number of substrate through-holes 6A may be one or more.

[0050] FIG. 12 is a plan view showing an example in which a board through-hole 6A is provided in a printed circuit board 3 in a mounting board 1 including a BGA 2B according to this embodiment.

[0051] As shown in Figure 12, the BGA 2B has solder balls 23 as multiple connection terminals 22. The printed circuit board 3 has lands 32 to which the solder balls 23 of the BGA 2B are bonded in the portion where the BGA 2B is mounted. The printed circuit board 3 does not have lands 32 in an area opposite an area of ​​the BGA 2B where no solder balls 23 are provided. This area without lands 32 is referred to as a non-land area R1. Furthermore, in the BGA 2B, the area where multiple solder balls 23 are provided is referred to as a contact area Q2, and the area where no solder balls 23 are provided is referred to as a non-contact area Q1.

[0052] 12, a BGA 2B may have a contact area Q2 in which multiple solder balls 23 are provided in a rectangular central area (e.g., the area where a die 44 is present), a non-contact area Q1 surrounding the central contact area Q2, and a contact area Q2 in which multiple solder balls 23 are provided surrounding the non-contact area Q1. In this case, the area of ​​the printed circuit board 3 facing the non-contact area Q1 is a non-land area R1. The die 44 may be interpreted as other terms such as a silicon die or an IC chip.

[0053] The substrate through holes 6A may be provided in the non-land region R1. For example, as shown in Fig. 12, two substrate through holes 6A are provided at opposing corner positions of the non-land region R1. This allows the two substrate through holes 6A to be positioned sufficiently apart from each other, thereby preventing both substrate through holes 6A from being blocked by the reinforcing resin 4 of the side fill. The number of substrate through holes 6A is not limited to two, and may be one, or three or more.

[0054] FIG. 13 is a plan view showing a first example of a mounting board 1 including a BGA 2B according to this embodiment, in which through holes 6 are provided in the printed circuit board 3 and the BGA 2B.

[0055] Two board through-holes 6A may be provided at opposing corners of the non-land area R1 of the printed circuit board 3. Two component through-holes 6B may be provided at opposing corners of the non-contact area Q1 of the BGA 2B.

[0056] The substrate through holes 6A and the component through holes 6B may be positioned differently from each other. That is, the substrate through holes 6A and the component through holes 6B may not be aligned in a straight line in the Z-axis direction. For example, as shown in FIG. 13 , the two substrate through holes 6A and the two component through holes 6B may be positioned so that a third line L3 connecting the two substrate through holes 6A and a fourth line L4 connecting the two component through holes 6B intersect with each other. This prevents both the substrate through holes 6A and the component through holes 6B from being blocked by the reinforcing resin 4 of the side fill. The number of substrate through holes 6A is not limited to two and may be one, three, or more. The number of component through holes 6B is not limited to two and may be one, three, or more.

[0057] Fig. 14A is a plan view showing a second example in which through holes 6 are provided in the printed circuit board 3 and the BGA 2B in the mounting board 1 including the BGA 2B according to this embodiment. Fig. 14B is a cross-sectional view showing a second example in which through holes 6 are provided in the printed circuit board 3 and the BGA 2B in the mounting board 1 including the BGA 2B according to this embodiment.

[0058] 14A, the BGA 2B has a contact area Q2 in the center and a non-contact area Q1 surrounding the contact area Q2. In this case, the area of ​​the printed circuit board 3 facing the non-contact area Q1 (i.e., the area near the periphery of the BGA 2B) becomes the non-land area R1.

[0059] Two substrate through-holes 6A may be provided near opposing corners of the non-land area R1, and two component through-holes 6B may be provided near opposing corners of the non-contact area Q1.

[0060] The board through holes 6A and the component through holes 6B may be provided at different positions. That is, the board through holes 6A and the component through holes 6B may be provided so as not to be aligned in a straight line in the Z-axis direction. For example, as shown in Fig. 14A, the two board through holes 6A and the two component through holes 6B may be provided so that a fifth line L5 connecting the two board through holes 6A and a sixth line L6 connecting the two component through holes 6B intersect with each other.

[0061] Furthermore, the board through hole 6A may be provided so that the distance d1 between the board through hole 6A and the outer periphery of the BGA 2B is longer than the distance d2 between the bottom surface of the BGA 2B and the top surface of the printed circuit board 3 (i.e., so that the board through hole 6A is located on the inside). This prevents the side-fill reinforcing resin 4 that has infiltrated into the under-component space 5 from reaching the board through hole 6A. This prevents the board through hole 6A from being blocked by the side-fill reinforcing resin 4.

[0062] FIG. 15 is a plan view showing a first example in which, in a mounting substrate 1 having a BGA2B according to this embodiment, solder balls 23 are not provided on a portion of the BGA2B, and a substrate through-hole 6A is provided without providing a land 32 at a position on the printed circuit board 3 opposite the portion where the solder balls 23 are not provided.

[0063] 15, solder balls 23 may not be provided in the central portion of a BGA 2B (for example, the central portion of a die 44) where the influence of land leads is small, and lands 32 may not be provided in a position on the printed circuit board 3 opposite the portion where solder balls 23 are not provided. Then, a substrate through-hole 6A may be provided in the portion of the printed circuit board 3 where lands 32 are not provided. This allows the substrate through-hole 6A to be provided while minimizing the influence on the BGA 2B, even in a BGA 2B that does not have sufficient non-contact areas Q1 and non-land areas R1 as shown in FIG.

[0064] FIG. 16 is a plan view showing a second example in which, in a mounting substrate 1 having a BGA2B according to this embodiment, solder balls 23 are not provided on a portion of the BGA2B, and a substrate through-hole 6A is provided without providing a land 32 at a position on the printed circuit board 3 opposite the portion where the solder balls 23 are not provided.

[0065] As shown in FIG. 16 , solder balls 23 are not provided at positions outside the die 44 near the corners of the die 44 where durability damage is applied, and lands 32 are not provided at positions on the printed circuit board 3 facing the portions where the solder balls 23 are not provided. Then, substrate through holes 6A are provided in the portions of the printed circuit board 3 where the lands 32 are not provided. For example, two substrate through holes 6A may be provided on either side of the die 44, at positions outside the die 44 on the extension of the diagonal line E2 of the die 44. This prevents the two substrate through holes 6A from being blocked by the side-fill reinforcing resin 4. The number of substrate through holes 6A is not limited to two, and may be one, or three or more.

[0066] Fig. 17A is a plan view showing an example in which, in mounting board 1 including BGA 2B according to the present embodiment, component through-holes 6B are provided in part of the BGA 2B without providing solder balls 23, and substrate through-holes 6A are provided in positions on printed circuit board 3 facing the parts without solder balls 23 without providing lands 32. Fig. 17B is a cross-sectional view showing an example in which component through-holes 6B are provided in part of BGA 2B in mounting board 1 shown in Fig. 17A.

[0067] 17A and 17B, solder balls 23 are not provided near the corners of die 44 where durable damage is likely to occur, and lands 32 are not provided at positions on printed circuit board 3 facing the portions where solder balls 23 are not provided. Board through-holes 6A are provided at positions on printed circuit board 3 where lands 32 are not provided. Component through-holes 6B are provided at positions on BGA 2B where solder balls 23 are not provided.

[0068] The substrate through holes 6A and the component through holes 6B may be positioned differently from each other. That is, the substrate through holes 6A and the component through holes 6B may not be aligned in a straight line in the Z-axis direction. For example, the two substrate through holes 6A and the two component through holes 6B may be positioned so that a seventh line L7 connecting the two substrate through holes 6A and an eighth line L8 connecting the two component through holes 6B intersect with each other. This prevents both the substrate through holes 6A and the component through holes 6B from being blocked by the reinforcing resin 4 of the side fill. The number of substrate through holes 6A is not limited to two and may be one, three, or more. The number of component through holes 6B is not limited to two and may be one, three, or more.

[0069] FIG. 18 is a plan view showing an example in which the corners of the QFN 2A are not covered with the reinforcing resin 4 of the side fill in the mounting substrate 1 including the QFN 2A according to this embodiment.

[0070] When the non-contact area Q1 between the GND terminal 21 and the connection terminal 22 of the QFN 2A is narrow, a side-fill reinforcing resin 4 may be applied so as not to block at least one of the corners of the QFN 2A, as shown in FIG.

[0071] Furthermore, substrate through-holes 6A may be provided near the corners of the QFN 2A. This allows the reinforcing resin 4 to flow slightly when heated, as the fluidized reinforcing resin 4 flows down through the substrate through-holes 6A, preventing the reinforcing resin 4 from blocking the substrate through-holes 6A. At least one corner of the QFN 2A may be chamfered. At least one corner of the QFN 2A may be formed in the shape of a quarter-circle hole.

[0072] Summary of the Disclosure The contents of the present disclosure can be expressed as follows:

[0073] <Appendix 1> In a mounting board 1 in which an electronic component 2 is mounted on a printed circuit board 3, the electronic component 2 is surface-mounted on the printed circuit board 3, and a side-fill resin 4 is applied to the outer periphery thereof, and a through-hole 6 that connects to the space formed by the printed circuit board 3, the electronic component 2, and the side-fill resin 4 (i.e., the space under the component 5) is provided in at least one of the printed circuit board 3 and the electronic component 2. As a result, air and moisture in the under-component space 5 that expands due to heating are discharged to the outside through the through-holes 6, so that holes in the side-fill resin 4 can be prevented.

[0074] <Appendix 2> In the mounting board 1 described in Supplementary Note 1, the through-hole 6 may be provided inside the outer periphery of the electronic component 2 by a predetermined distance or more. As a result, even if the side-fill resin 4 penetrates into the space 5 in the gap between the electronic component 2 and the printed circuit board, the side-fill resin 4 does not reach the through-hole 6. Therefore, it is possible to prevent the through-hole 6 from being blocked by the side-fill resin 4.

[0075] <Appendix 3> In the mounting board 1 described in Supplementary Note 1 or 2, the through-holes 6 may be provided in both the printed circuit board 3 and the electronic component 2. This makes it possible to prevent all of the through holes 6 from being blocked.

[0076] <Appendix 4> In the mounting board 1 described in Supplementary Note 3, the through-hole 6 of the printed circuit board 3 (that is, the board through-hole 6A) and the through-hole 6 of the electronic component 2 (that is, the component through-hole 6B) may be provided at different positions in a plan view. This makes it possible to prevent the board through-hole 6A and the component through-hole 6B from being blocked at the same time.

[0077] <Appendix 5> In the mounting board 1 described in any one of Supplementary Notes 1 to 4, the electronic component 2 is a QFN (Quad Flat Non-leaded package) 2A, and the through-hole 6A in the printed circuit board 3 may be provided so as to avoid the GND land 31 of the QFN 2A. As a result, the substrate through-hole 6A is connected to the sub-component space 5 without being obstructed by the GND land 31.

[0078] <Appendix 6> In the mounting board 1 described in Supplementary Note 5, at least two through holes 6A may be provided in the printed circuit board 3 with the GND land 31 sandwiched between them. As a result, at least two substrate through holes 6A are positioned sufficiently apart from each other, and therefore, the possibility that both of the two substrate through holes 6A will be blocked by the side-fill resin 4 can be avoided.

[0079] <Appendix 7> In the mounting board 1 described in Supplementary Note 5, the through-holes 6A of the printed circuit board 3 may be provided between a plurality of divided GND lands 43 obtained by dividing the GND land 31. This allows the substrate through-hole 6A to be provided even when the non-contact area Q1 between the GND terminal 21 and the connection terminal 22 of the QFN 2A is narrow.

[0080] <Appendix 8> In the mounting board 1 described in Supplementary Note 5, the size of the GND land 31 may be smaller than the size of the GND terminal 21 of the QFN 2A joined to the GND land 31 by solder (for example, solder joint 7). As a result, the non-land area R1 where the GND land 31 does not exist becomes wider by the amount that the size of the GND land 31 is reduced, so that the substrate through-hole 6A can be provided only when the non-contact area Q1 between the GND terminal 21 and the connection terminal 22 of the QFN 2A is narrow.

[0081] <Appendix 9> In the mounting board 1 described in Supplementary Note 8, the outer periphery of the solder (for example, the solder joint 7) that joins the GND land 31 and the GND terminal 21 may be surrounded by resin 41. Providing this resin 41 can prevent board through-hole 6A from being blocked by flux residue of the solder (for example, solder joint 7) that joins GND land 31 to GND terminal 21. In addition, providing this resin 41 prevents QFN 2A from sinking in the direction approaching printed circuit board 3, thereby preventing board through-hole 6A from being blocked by sinking of QFN 2A.

[0082] <Appendix 10> In the mounting board 1 described in any one of Supplementary Notes 1 to 4, the electronic component 2 is a BGA (Ball Grid Array) 2B, and the through-hole 6A in the printed circuit board 3 may be provided so as to avoid the solder balls 23 arranged on the BGA 2B. As a result, the substrate through-hole 6A is connected to the sub-component space 5 without being obstructed by the solder balls 23.

[0083] <Appendix 11> In the mounting board 1 described in Appendix 10, the solder ball 23 is not provided at the center position of the die 44 placed on the BGA 2B, and the through hole 6A of the printed circuit board 3 may be provided at a position where the solder ball 23 at the center of the die 44 is not provided. This allows the substrate through-hole 6A to be provided while minimizing the effect on the BGA 2B.

[0084] <Appendix 12> In the mounting board 1 described in Appendix 10, solder balls 23 are not provided at positions outside the corners of the die 44 placed on the BGA 2B, and the through holes 6A of the printed circuit board 3 may be provided at positions outside the corners of the die 44 where solder balls 23 are not provided. This allows the substrate through-hole 6A to be provided while minimizing the effect on the BGA 2B.

[0085] <Appendix 13> In the mounting board 1 described in Supplementary Note 12, at least two through holes 6A may be provided in the printed circuit board 3, with the die 44 sandwiched between them. As a result, at least two substrate through holes 6A are positioned sufficiently apart from each other, and therefore, the possibility that both of the two substrate through holes 6A will be blocked by the side-fill resin 4 can be avoided.

[0086] <Appendix 14> In the mounting board 1 described in Supplementary Note 10, the distance d1 between the through hole 6A of the printed circuit board 3 and the outer periphery of the BGA 2B may be longer than the distance d2 between the bottom surface of the BGA 2B and the top surface of the printed circuit board 3. This prevents the side-fill resin 4 that has entered the under-component space 5 from reaching the board through-hole 6A, thereby preventing the board through-hole 6A from being blocked by the side-fill resin 4.

[0087] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications, alterations, substitutions, additions, deletions, and equivalents within the scope of the claims, and it is understood that these also fall within the technical scope of the present disclosure. Furthermore, the components in the above-described embodiments may be combined in any manner without departing from the spirit of the invention. [Industrial Applicability]

[0088] The technology of the present disclosure is useful for mounting substrates that are reinforced by side-fill resin. [Explanation of symbols]

[0089] 1 Mounting board 2. Electronic Components 2A QFN 2B BGA 3 Printed circuit board 4 Reinforcing resin 6 through holes 6A PCB through hole 6B Parts through hole 7 Solder joints 21 GND terminal 22 Connection terminal 23 Solder balls 31 GND land 32 rand 41 Protective resin 42 Cut Area 43 Split GND land 44 Die Q1 Non-contact area Q2 Contact area R1 Non-land area

Claims

1. A mounting board on which electronic components are mounted, The electronic component is surface-mounted on the printed circuit board, and a side-fill resin is applied to the outer periphery thereof. a through hole communicating with a space formed by the printed circuit board, the electronic component, and the side fill resin is provided in at least one of the printed circuit board and the electronic component; The through holes are provided in the printed circuit board and the electronic component, respectively. Mounting board.

2. The through hole is provided at a position inside the outer periphery of the electronic component by a predetermined distance or more. The mounting board according to claim 1 .

3. the through hole of the printed circuit board and the through hole of the electronic component are provided at different positions from each other in a plan view; The mounting board according to claim 1 .

4. the electronic component is a QFN (Quad Flat Non-leaded package), the through-holes in the printed circuit board are provided so as to avoid the GND lands of the QFN; The mounting board according to claim 1 .

5. A printed circuit board on which electronic components are mounted, comprising: The electronic component is surface-mounted on the printed circuit board, and a side-fill resin is applied to the outer periphery thereof. a through hole communicating with a space formed by the printed circuit board, the electronic component, and the side fill resin is provided in at least one of the printed circuit board and the electronic component; the electronic component is a QFN (Quad Flat Non-leaded package), the through-hole of the printed circuit board is provided so as to avoid the GND land of the QFN; At least two through holes are provided in the printed circuit board, with the GND land sandwiched between them. Mounting board.

6. the through holes of the printed circuit board are provided between a plurality of divided GND lands obtained by dividing the GND land; The mounting board according to claim 5 .

7. the size of the GND land is smaller than the size of the GND terminal of the QFN to be joined to the GND land by soldering; The mounting board according to claim 5 .

8. The outer periphery of the solder that joins the GND land and the GND terminal is surrounded by resin. The mounting board according to claim 7 .

9. the electronic component is a BGA (Ball Grid Array), the through holes of the printed circuit board are provided so as to avoid the solder balls arranged on the BGA; The mounting board according to claim 1 .

10. The solder balls are not provided at the center of the die arranged on the BGA, the through-hole of the printed circuit board is provided at a position in the center of the die where the solder balls are not provided; The mounting board according to claim 9 .

11. A mounting board on which electronic components are mounted, comprising: The electronic component is surface-mounted on the printed circuit board, and a side-fill resin is applied to the outer periphery thereof. a through hole communicating with a space formed by the printed circuit board, the electronic component, and the side fill resin is provided in at least one of the printed circuit board and the electronic component; the electronic component is a BGA (Ball Grid Array), the through holes of the printed circuit board are provided so as to avoid the solder balls arranged on the BGA; The solder balls are not provided at corners of the die arranged on the BGA at positions outside the die, the through-holes of the printed circuit board are provided at corners of the die at positions outside the die where the solder balls are not provided; Mounting board.

12. At least two through holes are provided in the printed circuit board, with the die sandwiched between them. The mounting board according to claim 11 .

13. the distance between the through-hole of the printed circuit board and the outer periphery of the BGA is longer than the distance between the bottom surface of the BGA and the top surface of the printed circuit board; The mounting board according to claim 11 .

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